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Sample records for estimate tuberculosis transmission

  1. A Novel Tool Improves Existing Estimates of Recent Tuberculosis Transmission in Settings of Sparse Data Collection.

    PubMed

    Kasaie, Parastu; Mathema, Barun; Kelton, W David; Azman, Andrew S; Pennington, Jeff; Dowdy, David W

    2015-01-01

    In any setting, a proportion of incident active tuberculosis (TB) reflects recent transmission ("recent transmission proportion"), whereas the remainder represents reactivation. Appropriately estimating the recent transmission proportion has important implications for local TB control, but existing approaches have known biases, especially where data are incomplete. We constructed a stochastic individual-based model of a TB epidemic and designed a set of simulations (derivation set) to develop two regression-based tools for estimating the recent transmission proportion from five inputs: underlying TB incidence, sampling coverage, study duration, clustered proportion of observed cases, and proportion of observed clusters in the sample. We tested these tools on a set of unrelated simulations (validation set), and compared their performance against that of the traditional 'n-1' approach. In the validation set, the regression tools reduced the absolute estimation bias (difference between estimated and true recent transmission proportion) in the 'n-1' technique by a median [interquartile range] of 60% [9%, 82%] and 69% [30%, 87%]. The bias in the 'n-1' model was highly sensitive to underlying levels of study coverage and duration, and substantially underestimated the recent transmission proportion in settings of incomplete data coverage. By contrast, the regression models' performance was more consistent across different epidemiological settings and study characteristics. We provide one of these regression models as a user-friendly, web-based tool. Novel tools can improve our ability to estimate the recent TB transmission proportion from data that are observable (or estimable) by public health practitioners with limited available molecular data. PMID:26679499

  2. A Novel Tool Improves Existing Estimates of Recent Tuberculosis Transmission in Settings of Sparse Data Collection

    PubMed Central

    Kasaie, Parastu; Mathema, Barun; Kelton, W. David; Azman, Andrew S.; Pennington, Jeff; Dowdy, David W.

    2015-01-01

    In any setting, a proportion of incident active tuberculosis (TB) reflects recent transmission (“recent transmission proportion”), whereas the remainder represents reactivation. Appropriately estimating the recent transmission proportion has important implications for local TB control, but existing approaches have known biases, especially where data are incomplete. We constructed a stochastic individual-based model of a TB epidemic and designed a set of simulations (derivation set) to develop two regression-based tools for estimating the recent transmission proportion from five inputs: underlying TB incidence, sampling coverage, study duration, clustered proportion of observed cases, and proportion of observed clusters in the sample. We tested these tools on a set of unrelated simulations (validation set), and compared their performance against that of the traditional ‘n-1’ approach. In the validation set, the regression tools reduced the absolute estimation bias (difference between estimated and true recent transmission proportion) in the ‘n-1’ technique by a median [interquartile range] of 60% [9%, 82%] and 69% [30%, 87%]. The bias in the ‘n-1’ model was highly sensitive to underlying levels of study coverage and duration, and substantially underestimated the recent transmission proportion in settings of incomplete data coverage. By contrast, the regression models’ performance was more consistent across different epidemiological settings and study characteristics. We provide one of these regression models as a user-friendly, web-based tool. Novel tools can improve our ability to estimate the recent TB transmission proportion from data that are observable (or estimable) by public health practitioners with limited available molecular data. PMID:26679499

  3. The transmission of Mycobacterium tuberculosis in high burden settings.

    PubMed

    Yates, Tom A; Khan, Palwasha Y; Knight, Gwenan M; Taylor, Jonathon G; McHugh, Timothy D; Lipman, Marc; White, Richard G; Cohen, Ted; Cobelens, Frank G; Wood, Robin; Moore, David A J; Abubakar, Ibrahim

    2016-02-01

    Unacceptable levels of Mycobacterium tuberculosis transmission are noted in high burden settings and a renewed focus on reducing person-to-person transmission in these communities is needed. We review recent developments in the understanding of airborne transmission. We outline approaches to measure transmission in populations and trials and describe the Wells-Riley equation, which is used to estimate transmission risk in indoor spaces. Present research priorities include the identification of effective strategies for tuberculosis infection control, improved understanding of where transmission occurs and the transmissibility of drug-resistant strains, and estimates of the effect of HIV and antiretroviral therapy on transmission dynamics. When research is planned and interventions are designed to interrupt transmission, resource constraints that are common in high burden settings-including shortages of health-care workers-must be considered. PMID:26867464

  4. Tuberculosis transmission in a large urban jail.

    PubMed

    King, L; Geis, G

    1977-02-21

    Following diagnosis of moderately advanced tuberculosis in an inmate of Cook County Jail, tuberculin testing was performed to assess the degree of transmission of tuberculosis within the jail. Twenty-three percent of inmates exposed to the index patient were initially found to be tuberculin positive. Subsequent tuberculin testing three months later demonstrated a 71% rate of skin-test conversion in previously tuberculin-negative inmates exposed to the index patient. The rate of infectivity of tuberculosis within a jail is analogous to a household situation. Despite major obstacles, modern programs of tuberculosis screening and treatment are essential in correctional institutions. PMID:576316

  5. Recent Transmission of Tuberculosis — United States, 2011–2014

    PubMed Central

    Yuen, Courtney M.; Kammerer, J. Steve; Marks, Kala; Navin, Thomas R.; France, Anne Marie

    2016-01-01

    Tuberculosis is an infectious disease that may result from recent transmission or from an infection acquired many years in the past; there is no diagnostic test to distinguish the two causes. Cases resulting from recent transmission are particularly concerning from a public health standpoint. To describe recent tuberculosis transmission in the United States, we used a field-validated plausible source-case method to estimate cases likely resulting from recent transmission during January 2011–September 2014. We classified cases as resulting from either limited or extensive recent transmission based on transmission cluster size. We used logistic regression to analyze patient characteristics associated with recent transmission. Of 26,586 genotyped cases, 14% were attributable to recent transmission, 39% of which were attributable to extensive recent transmission. The burden of cases attributed to recent transmission was geographically heterogeneous and poorly predicted by tuberculosis incidence. Extensive recent transmission was positively associated with American Indian/Alaska Native (adjusted prevalence ratio [aPR] = 3.6 (95% confidence interval [CI] 2.9–4.4), Native Hawaiian/Pacific Islander (aPR = 3.2, 95% CI 2.3–4.5), and black (aPR = 3.0, 95% CI 2.6–3.5) race, and homelessness (aPR = 2.3, 95% CI 2.0–2.5). Extensive recent transmission was negatively associated with foreign birth (aPR = 0.2, 95% CI 0.2–0.2). Tuberculosis control efforts should prioritize reducing transmission among higher-risk populations. PMID:27082644

  6. Recent Transmission of Tuberculosis - United States, 2011-2014.

    PubMed

    Yuen, Courtney M; Kammerer, J Steve; Marks, Kala; Navin, Thomas R; France, Anne Marie

    2016-01-01

    Tuberculosis is an infectious disease that may result from recent transmission or from an infection acquired many years in the past; there is no diagnostic test to distinguish the two causes. Cases resulting from recent transmission are particularly concerning from a public health standpoint. To describe recent tuberculosis transmission in the United States, we used a field-validated plausible source-case method to estimate cases likely resulting from recent transmission during January 2011-September 2014. We classified cases as resulting from either limited or extensive recent transmission based on transmission cluster size. We used logistic regression to analyze patient characteristics associated with recent transmission. Of 26,586 genotyped cases, 14% were attributable to recent transmission, 39% of which were attributable to extensive recent transmission. The burden of cases attributed to recent transmission was geographically heterogeneous and poorly predicted by tuberculosis incidence. Extensive recent transmission was positively associated with American Indian/Alaska Native (adjusted prevalence ratio [aPR] = 3.6 (95% confidence interval [CI] 2.9-4.4), Native Hawaiian/Pacific Islander (aPR = 3.2, 95% CI 2.3-4.5), and black (aPR = 3.0, 95% CI 2.6-3.5) race, and homelessness (aPR = 2.3, 95% CI 2.0-2.5). Extensive recent transmission was negatively associated with foreign birth (aPR = 0.2, 95% CI 0.2-0.2). Tuberculosis control efforts should prioritize reducing transmission among higher-risk populations. PMID:27082644

  7. Congenital Transmission of Multidrug-Resistant Tuberculosis

    PubMed Central

    Espiritu, Nora; Aguirre, Lino; Jave, Oswaldo; Sanchez, Luis; Kirwan, Daniela E.; Gilman, Robert H.

    2014-01-01

    This article presents a case of multidrug-resistant tuberculosis (TB) in a Peruvian infant. His mother was diagnosed with disseminated TB, and treatment commenced 11 days postpartum. The infant was diagnosed with TB after 40 days and died at 2 months and 2 days of age. Congenital transmission of TB to the infant was suspected, because direct postpartum transmission was considered unlikely; also, thorough screening of contacts for TB was negative. Spoligotyping confirmed that both mother and baby were infected with identical strains of the Beijing family (SIT1). PMID:24821847

  8. Transforming the Fight Against Tuberculosis: Targeting Catalysts of Transmission

    PubMed Central

    Dowdy, David W.; Azman, Andrew S.; Kendall, Emily A.; Mathema, Barun

    2014-01-01

    The global tuberculosis control community has committed itself to ambitious 10-year targets. To meet these targets, biomedical advances alone will be insufficient; a more targeted public health tuberculosis strategy is also needed. We highlight the role of “tuberculosis transmission catalysts,” defined as variabilities in human behavior, bacillary properties, and host physiology that fuel the propagation of active tuberculosis at the local level. These catalysts can be categorized as factors that increase contact rates, infectiousness, or host susceptibility. Different catalysts predominate in different epidemiological and sociopolitical settings, and public health approaches are likely to succeed only if they are tailored to target the major catalysts driving transmission in the corresponding community. We argue that global tuberculosis policy should move from a country-level focus to a strategy that prioritizes collection of data on key transmission catalysts at the local level followed by deployment of “catalyst-targeted” interventions, supported by strengthened health systems. PMID:24982034

  9. Is Early Tuberculosis Death Associated with Increased Tuberculosis Transmission?

    PubMed Central

    Parhar, Anu; Gao, Zhiwei; Heffernan, Courtney; Ahmed, Rabia; Egedahl, Mary Lou; Long, Richard

    2015-01-01

    Introduction Tuberculosis (TB) is now a relatively uncommon disease in high income countries. As such, its diagnosis may be missed or delayed resulting in death before or shortly after the introduction of treatment. Whether early TB death is associated with increased TB transmission is unknown. To determine the transmission risk attributable to early TB death we undertook a case-control study. Methods All adults who were: (1) diagnosed with culture-positive pulmonary TB in the Province of Alberta, Canada between 1996 and 2012, and (2) died a TB-related death before or within the first 60 days of treatment, were identified. For each of these “cases” two sets of “controls” were randomly selected from among culture-positive pulmonary TB cases that survived beyond 60 days of treatment. “Controls” were matched by age, sex, population group, +/- smear status. Secondary cases of “cases” and “controls” were identified using conventional and molecular epidemiologic tools and compared. In addition, new infections were identified and compared in contacts of “cases” that died before treatment and contacts of their smear-matched “controls”. Conditional logistic regression was used to find associations in both univariate and multivariate analysis. Results “Cases” were as, but not more, likely than “controls” to transmit. This was so whether transmission was measured in terms of the number of “cases” and smear-unmatched or -matched “controls” that had a secondary case, the number of secondary cases that they had or the number of new infections found in contacts of “cases” that died before treatment and their smear-matched “controls”. Conclusion In a low TB incidence/low HIV prevalence country, pulmonary TB patients that die a TB-related death before or in the initial phase of treatment and pulmonary TB patients that survive beyond the initial phase of treatment are equally likely to transmit. PMID:25622038

  10. Evaluation of large genotypic Mycobacterium tuberculosis clusters: contributions from remote and recent transmission.

    PubMed

    Teeter, Larry D; Ha, Ngan P; Ma, Xin; Wenger, Jane; Cronin, Wendy A; Musser, James M; Graviss, Edward A

    2013-12-01

    Tuberculosis genotypic clustering is used as a proxy for recent transmission. The association between clustering and recent transmission becomes problematic when the genotyping method lacks specificity in defining a cluster, as well as for clusters with extensive jurisdictional histories and/or common genotypes. We investigated the four largest spoligotype/12 loci MIRU-VNTR-defined clusters in Harris County, Texas from 2006-2012 to determine their historical contribution to tuberculosis morbidity, estimate the contributions from recent and remote transmission, and determine the impact of secondary genotyping on cluster definition. The clusters contained 189, 64, 51 and 38 cases. Each cluster was linked to cluster(s) previously identified by Houston Tuberculosis Initiative; 3 since 1995 and the fourth in 2002. Among cases for which timing of Mycobacterium tuberculosis transmission relative to tuberculosis disease could be ascertained, nearly equal proportions were associated with recent and remote transmission. The extent to which genotyping with an additional 12 MIRU-VNTR loci modified the cluster definition varied from little or no impact for the two smaller clusters to moderate impact for the larger clusters. Tuberculosis control measures to reduce morbidity associated with large clusters must involve strategies to identify and treat individuals who recently acquired infection, as well as persons infected for years. PMID:24388648

  11. Interventions to reduce tuberculosis mortality and transmission in low- and middle-income countries.

    PubMed Central

    Borgdorff, Martien W.; Floyd, Katherine; Broekmans, Jaap F.

    2002-01-01

    Tuberculosis is among the top ten causes of global mortality and affects low-income countries in particular. This paper examines, through a literature review, the impact of tuberculosis control measures on tuberculosis mortality and transmission, and constraints to scaling-up. It also provides estimates of the effectiveness of various interventions using a model proposed by Styblo. It concludes that treatment of smear-positive tuberculosis using the WHO directly observed treatment, short-course (DOTS) strategy has by far the highest impact. While BCG immunization reduces childhood tuberculosis mortality, its impact on tuberculosis transmission is probably minimal. Under specific conditions, an additional impact on mortality and transmission can be expected through treatment of smear-negative cases, intensification of case-finding for smear-positive tuberculosis, and preventive therapy among individuals with dual tuberculosis-HIV infection. Of these interventions, DOTS is the most cost-effective at around US$ 5-40 per disability-adjusted life year (DALY) gained. The cost for BCG immunization is likely to be under US$ 50 per DALY gained. Treatment of smear-negative patients has a cost per DALY gained of up to US$ 100 in low-income countries, and up to US$ 400 in middle-income settings. Other interventions, such as preventive therapy for HIV-positive individuals, appear to be less cost-effective. The major constraint to scaling up DOTS is lack of political commitment, resulting in shortages of funding and human resources for tuberculosis control. However, in recent years there have been encouraging signs of increasing political commitment. Other constraints are related to involvement of the private sector, health sector reform, management capacity of tuberculosis programmes, treatment delivery, and drug supply. Global tuberculosis control could benefit strongly from technical innovation, including the development of a vaccine giving good protection against smear

  12. Elephant-to-Human Transmission of Tuberculosis, 2009

    PubMed Central

    Warkentin, Jon V.; Dunn, John R.; Schaffner, William; Jones, Timothy F.

    2011-01-01

    In 2009, the Tennessee Department of Health received reports of 5 tuberculin skin test (TST) conversions among employees of an elephant refuge and isolation of Mycobacterium tuberculosis from a resident elephant. To determine the extent of the outbreak and identify risk factors for TST conversion, we conducted a cohort study and onsite assessment. Risk for conversion was increased for elephant caregivers and administrative employees working in the barn housing the M. tuberculosis–infected elephant or in offices connected to the barn (risk ratio 20.3, 95% confidence interval 2.8–146.7). Indirect exposure to aerosolized M. tuberculosis and delayed or inadequate infection control practices likely contributed to transmission. The following factors are needed to reduce risk for M. tuberculosis transmission in the captive elephant industry: increased knowledge about M. tuberculosis infection in elephants, improved infection control practices, and specific occupational health programs. PMID:21392425

  13. A probabilistic transmission model to assess infection risk from Mycobacterium tuberculosis in commercial passenger trains.

    PubMed

    Chen, Szu-Chieh; Liao, Chung-Min; Li, Sih-syuan; You, Shu-Han

    2011-06-01

    The objective of this article is to characterize the risk of infection from airborne Mycobacterium tuberculosis bacilli exposure in commercial passenger trains based on a risk-based probabilistic transmission modeling. We investigated the tuberculosis (TB) infection risks among commercial passengers by inhaled aerosol M. tuberculosis bacilli and quantify the patterns of TB transmission in Taiwan High Speed Rail (THSR). A deterministic Wells-Riley mathematical model was used to account for the probability of infection risk from M. tuberculosis bacilli by linking the cough-generated aerosol M. tuberculosis bacilli concentration and particle size distribution. We found that (i) the quantum generation rate of TB was estimated with a lognormal distribution of geometric mean (GM) of 54.29 and geometric standard deviation (GSD) of 3.05 quantum/h at particle size ≤ 5 μm and (ii) the basic reproduction numbers (R(0) ) were estimated to be 0.69 (0.06-6.79), 2.82 (0.32-20.97), and 2.31 (0.25-17.69) for business, standard, and nonreserved cabins, respectively. The results indicate that commercial passengers taking standard and nonreserved cabins had higher transmission risk than those in business cabins based on conservatism. Our results also reveal that even a brief exposure, as in the bronchoscopy cases, can also result in a transmission when the quantum generation rate is high. This study could contribute to a better understanding of the dynamics of TB transmission in commercial passenger trains by assessing the relationship between TB infectiousness, passenger mobility, and key model parameters such as seat occupancy, ventilation rate, and exposure duration. PMID:21175727

  14. Transmission of Multidrug-Resistant and Drug-Susceptible Tuberculosis within Households: A Prospective Cohort Study

    PubMed Central

    Grandjean, Louis; Gilman, Robert H.; Martin, Laura; Soto, Esther; Castro, Beatriz; Lopez, Sonia; Coronel, Jorge; Castillo, Edith; Alarcon, Valentina; Lopez, Virginia; San Miguel, Angela; Quispe, Neyda; Asencios, Luis; Dye, Christopher; Moore, David A. J.

    2015-01-01

    Background The “fitness” of an infectious pathogen is defined as the ability of the pathogen to survive, reproduce, be transmitted, and cause disease. The fitness of multidrug-resistant tuberculosis (MDRTB) relative to drug-susceptible tuberculosis is cited as one of the most important determinants of MDRTB spread and epidemic size. To estimate the relative fitness of drug-resistant tuberculosis cases, we compared the incidence of tuberculosis disease among the household contacts of MDRTB index patients to that among the contacts of drug-susceptible index patients. Methods and Findings This 3-y (2010–2013) prospective cohort household follow-up study in South Lima and Callao, Peru, measured the incidence of tuberculosis disease among 1,055 household contacts of 213 MDRTB index cases and 2,362 household contacts of 487 drug-susceptible index cases. A total of 35/1,055 (3.3%) household contacts of 213 MDRTB index cases developed tuberculosis disease, while 114/2,362 (4.8%) household contacts of 487 drug-susceptible index patients developed tuberculosis disease. The total follow-up time for drug-susceptible tuberculosis contacts was 2,620 person-years, while the total follow-up time for MDRTB contacts was 1,425 person-years. Using multivariate Cox regression to adjust for confounding variables including contact HIV status, contact age, socio-economic status, and index case sputum smear grade, the hazard ratio for tuberculosis disease among MDRTB household contacts was found to be half that for drug-susceptible contacts (hazard ratio 0.56, 95% CI 0.34–0.90, p = 0.017). The inference of transmission in this study was limited by the lack of genotyping data for household contacts. Capturing incident disease only among household contacts may also limit the extrapolation of these findings to the community setting. Conclusions The low relative fitness of MDRTB estimated by this study improves the chances of controlling drug-resistant tuberculosis. However, fitter

  15. Transmissibility of Tuberculosis among School Contacts: An Outbreak Investigation in a Boarding Middle School, China

    PubMed Central

    Ma, Mai-Juan; Yang, Yang; Wang, Hai-Bin; Zhu, Yi-Fan; Fang, Li-Qun; An, Xiao-Ping; Wan, Kang-Lin; Whalen, Christopher C.; Yang, Xiao-Xian; Lauzardo, Michael; Zhang, Zhi-Yi; Cao, Jin-Feng; Tong, Yi-Gang; Dai, Er-Hei; Cao, Wu-Chun

    2015-01-01

    Tuberculosis (TB) outbreak occurred in a boarding middle school of China. We explored its probable sources and quantified the transmissibility and pathogenicity of TB. Clinical evaluation, tuberculin skin testing and chest radiography were conducted to identify TB cases. Mycobacterium tuberculosis isolates underwent genotyping analysis to identify the outbreak source. A chain-binomial transmission model was used to evaluate transmissibility and pathogenicity of TB. A total of 46 active cases were ascertained among 258 students and 15 teachers/staff, an attack rate of 16.8%. Genetic analyses revealed two groups of M. tuberculosis cocirculating during the outbreak and possible importation from local communities. Secondary attack rates among students were 4.1% (2.9%, 5.3%) within grade and 7.9% (4.9%, 11%) within class. An active TB case was estimated to infect 8.4 (7.2, 9.6) susceptible people on average. The smear-positive cases were 28 (8, 101) times as infective as smear-negative cases. Previous BCG vaccination could reduce the probability of developing symptoms after infection by 70% (1.4%, 91%). The integration of clinical evaluation, genetic sequencing, and statistical modeling greatly enhanced our understanding of TB transmission dynamics. Timely diagnosis of smear-positive cases, especially in the early phase of the outbreak, is the key to preventing further spread among close contacts. PMID:25757905

  16. Four decades of transmission of a multidrug-resistant Mycobacterium tuberculosis outbreak strain

    PubMed Central

    Eldholm, Vegard; Monteserin, Johana; Rieux, Adrien; Lopez, Beatriz; Sobkowiak, Benjamin; Ritacco, Viviana; Balloux, Francois

    2015-01-01

    The rise of drug-resistant strains is a major challenge to containing the tuberculosis (TB) pandemic. Yet, little is known about the extent of resistance in early years of chemotherapy and when transmission of resistant strains on a larger scale became a major public health issue. Here we reconstruct the timeline of the acquisition of antimicrobial resistance during a major ongoing outbreak of multidrug-resistant TB in Argentina. We estimate that the progenitor of the outbreak strain acquired resistance to isoniazid, streptomycin and rifampicin by around 1973, indicating continuous circulation of a multidrug-resistant TB strain for four decades. By around 1979 the strain had acquired additional resistance to three more drugs. Our results indicate that Mycobacterium tuberculosis (Mtb) with extensive resistance profiles circulated 15 years before the outbreak was detected, and about one decade before the earliest documented transmission of Mtb strains with such extensive resistance profiles globally. PMID:25960343

  17. A Missed Tuberculosis Diagnosis Resulting in Hospital Transmission

    PubMed Central

    Medrano, Belinda A.; Salinas, Gloria; Sanchez, Connie; Miramontes, Roque; Restrepo, Blanca I.; Haddad, Maryam B.; Lambert, Lauren A.

    2016-01-01

    OBJECTIVE To find the source of tuberculin skin test conversions among 38 hospital employees on 1 floor during routine testing January–February 2010. METHODS Record review of patients at a private hospital during September–December 2009 and interviews with hospital employees. Names of patients from the state tuberculosis (TB) registry were cross-referenced with hospital records for admissions. Mycobacterium tuberculosis genotype results in the county and adjacent counties were examined, and contacts were evaluated for TB infection and disease. RESULTS One of the 38 employees, a nurse, was diagnosed with pulmonary TB with a matching M. tuberculosis genotype and drug resistance pattern (isoniazid monoresistant) to those of a county jail inmate also recently diagnosed with pulmonary TB. The nurse had no known contact with that inmate; however, another inmate in his 20’s from the same jail had been hospitalized under that nurse’s care in October 2009. That young man died, and a postmortem examination result subsequently confirmed TB, which had not been suspected. Exposure to this man with undiagnosed TB could explain the transmission: 87 (27%) of the 318 hospital-based contacts without previous positive tuberculin skin test results were infected, and 9 contacts had active TB. CONCLUSIONS This investigation demonstrated M. tuberculosis transmission in a hospital due to a missed diagnosis and nonadherence to national TB infection control guidelines. Routine TB screening of employees allowed early detection of this missed TB diagnosis, facilitating prompt evaluation of contacts. Healthcare providers should suspect TB in symptomatic persons and adhere to TB control policies. PMID:24709722

  18. Transmission of Mycobacterium orygis (M. tuberculosis complex species) from a tuberculosis patient to a dairy cow in New Zealand.

    PubMed

    Dawson, Kara L; Bell, Anita; Kawakami, R Pamela; Coley, Kathryn; Yates, Gary; Collins, Desmond M

    2012-09-01

    Mycobacterium orygis, previously called the oryx bacillus, is a member of the Mycobacterium tuberculosis complex and has been reported only recently as a cause of human tuberculosis in patients of South Asian origin. We present the first case documenting the transmission of this organism from a human to a cow. PMID:22785186

  19. Risk factors for nosocomial tuberculosis transmission among health care workers.

    PubMed

    Ito, Yutaka; Nagao, Miki; Iinuma, Yoshitsugu; Matsumura, Yasufumi; Yamamoto, Masaki; Takakura, Shunji; Igawa, Junko; Yamanaka, Hiroe; Hashimoto, Akiko; Hirai, Toyohiro; Niimi, Akio; Ichiyama, Satoshi; Mishima, Michiaki

    2016-05-01

    We conducted hospital-based contact investigations of 55 serial sputum smear-positive tuberculosis (TB) patients and 771 health care workers (HCWs) from 2006-2013. HCWs who made contact with TB patients in the absence of appropriate airborne precautions were evaluated using interferon gamma release assays to identify TB infection. Twenty-nine HCWs (3.8%) were newly diagnosed with TB infection. The 10 TB patients responsible for transmission had a duration of contact of >7 days by multivariate analysis. PMID:26777287

  20. Mathematical Model Of Tuberculosis Transmission With Reccurent Infection And Vaccination

    NASA Astrophysics Data System (ADS)

    Nainggolan, J.; Supian, Sudradjat; Supriatna, A. K.; Anggriani, N.

    2013-04-01

    This paper presents a model of tuberculosis transmission with vaccination by explicitely considering the total number of recovered individuals, either from natural recovery or due to vaccination. In this paper the endemic and nonendemic fixed points, basic reproduction number, and vaccination reproduction number are given. Some results regarding the stability of the fixed points and the relation to the basic reproduction numbers are analysed. At the end of this study, the numerical computation presented and it shows that vaccination is capable to reduce the number of laten and infectious populations.

  1. Incidence and transmission patterns of tuberculosis among indigenous populations in Brazil

    PubMed Central

    Cunha, Eunice Atsuko; Ferrazoli, Lucilaine; Riley, Lee W; Basta, Paulo Cesar; Honer, Michael Robert; Maia, Rosalia; da Costa, Izaias Pereira

    2013-01-01

    Approximately 10% of the Brazilian indigenous population lives in the state of Mato Grosso do Sul (MS), where a large number of new cases of tuberculosis (TB) are reported. This study was conducted to assess TB occurrence, transmission and the utility of TB diagnosis based on the Ogawa-Kudoh (O-K) culture method in this remote population. The incidence of TB was estimated by a retrospective review of the surveillance data maintained by the Notifiable Diseases Surveillance System for the study region. The TB transmission pattern among indigenous people was assessed by genotyping Mycobacterium tuberculosis isolates using the IS 6110 restriction fragment length polymorphism (RFLP) technique. Of the 3,093 cases identified from 1999-2001, 610 (~20%) were indigenous patients (average incidence: 377/100,000/year). The use of the O-K culture method increased the number of diagnosed cases by 34.1%. Of the genotyped isolates from 52 indigenous patients, 33 (63.5%) belonged to cluster RFLP patterns, indicating recently transmitted TB. These results demonstrate high, on-going TB transmission rates among the indigenous people of MS and indicate that new efforts are needed to disrupt these current transmissions. PMID:24270999

  2. Prevalence and transmission of pyrazinamide resistant Mycobacterium tuberculosis in China.

    PubMed

    Xu, Peng; Wu, Jie; Yang, Chongguang; Luo, Tao; Shen, Xin; Zhang, Yangyi; Nsofor, Chijioke A; Zhu, Guofeng; Gicquel, Brigitte; Gao, Qian

    2016-05-01

    Pyrazinamide (PZA) is an important first-line anti-tuberculosis drug, however, there are relatively few available data on PZA resistant (PZA-R) rate in China. From June 2009 to June 2012, we selected 493 isolates from five field settings in China to investigate PZA-R by pncA gene sequencing. The result showed that PZA-R rate was 1.0% (2/196) among pan-susceptible isolates, 3.1% (4/130) among isoniazid (INH) mono-resistant isolates, 14.0% (6/43) among rifampin (RIF) mono-resistant isolates and 43.5% (54/124) among multidrug resistant (MDR) isolates. MDR tuberculosis (TB), RIF mono-resistance, and retreatment were found to be risk factors for PZA-R. Newly diagnosed PZA-R TB patients and clustered isolates with identical pncA mutations indicate that transmission of PZA-R isolates plays an important role in emergence of PZA-R TB. The results suggest that, it is necessary to conduct PZA susceptibility test among MDR isolates and modify the treatment regimens accordingly. PMID:27156619

  3. Migrant tuberculosis: the extent of transmission in a low burden country

    PubMed Central

    2012-01-01

    Background Human migration caused by political unrest, wars and poverty is a major topic in international health. Infectious diseases like tuberculosis follow their host, with potential impact on both the migrants and the population in the recipient countries. In this study, we evaluate Mycobacterium tuberculosis transmission between the national population and migrants in Denmark. Methods Register study based on IS6110-RFLP results from nationwide genotyping of tuberculosis cases during 1992 through 2004. Cases with 100% identical genotypes were defined as clustered and part of a transmission chain. Origin of clusters involving both Danes and migrants was defined as Danish/migrant/uncertain. Subsequently, the proportion of cases likely infected by the "opposite" ethnic group was estimated. Results 4,631 cases were included, representing 99% of culture confirmed cases during 1992 through 2004. Migrants contributed 61.6% of cases. Up to 7.9% (95% CI 7.0-8.9) of migrants were infected by Danes. The corresponding figure was 5.8% (95% CI 4.8-7.0) for Danes. Thus, transmission from Danes to migrants occurred up to 2.5 (95% CI 1.8-3.5) times more frequent than vice versa (OR = 1). A dominant strain, Cluster-2, was almost exclusively found in Danes, particular younger-middle-aged males. Conclusions Transmission between Danes and migrants is limited, and risk of being infected by the "opposite" ethnic group is highest for migrants. TB-control efforts should focus on continues micro-epidemics, e.g. with Cluster-2 in Danes, prevention of reactivation TB in high-risk migrants, and outbreaks in socially marginalized migrants, such as Somalis and Greenlanders. Fears that TB in migrants poses a threat for resident Danes seem exaggerated and unjustified. We believe this to be true for other low incidence countries as well. PMID:22423983

  4. Seasonality Impact on the Transmission Dynamics of Tuberculosis

    PubMed Central

    2016-01-01

    The statistical data of monthly pulmonary tuberculosis (TB) incidence cases from January 2004 to December 2012 show the seasonality fluctuations in Shaanxi of China. A seasonality TB epidemic model with periodic varying contact rate, reactivation rate, and disease-induced death rate is proposed to explore the impact of seasonality on the transmission dynamics of TB. Simulations show that the basic reproduction number of time-averaged autonomous systems may underestimate or overestimate infection risks in some cases, which may be up to the value of period. The basic reproduction number of the seasonality model is appropriately given, which determines the extinction and uniform persistence of TB disease. If it is less than one, then the disease-free equilibrium is globally asymptotically stable; if it is greater than one, the system at least has a positive periodic solution and the disease will persist. Moreover, numerical simulations demonstrate these theorem results. PMID:27042199

  5. Genotyping analyses of tuberculosis transmission among immigrant residents in Italy.

    PubMed

    Franzetti, F; Codecasa, L; Matteelli, A; Degli Esposti, A; Bandera, A; Lacchini, C; Lombardi, A; Pinsi, G; Zanini, F; El-Hamad, I; Gori, A

    2010-08-01

    We used DNA fingerprinting to analyse tuberculosis (TB) epidemiology in immigrant patients living in two major northern Italian urban areas. The study population included 1999 TB patients (1500 Italian-born and 499 immigrants). Univariate and multivariate logistic regression models were used to identify risk factors related to clustering similar proportions of immigrant and Italian-born patients (46%) had infection with TB strains that belonged to genetic clusters. This supports the hypothesis that the disease in foreign patients is more likely to have arisen from reactivation of latent infection acquired in the country of origin than from recent transmission. Gender, age, human immunodeficiency virus infection and drug resistance were not significantly linked to TB clustering. Risk factors associated with strain clustering were country of origin (Somalia, adjusted OR (AOR) 3.19, p 0.017; Peru, AOR 2.86, p 0.014; and Senegal, AOR 2.60, p 0.045) and city of residence. Immigrant status in the larger urban area was an independent risk factor for infection with clustered TB, as reinforced by a subanalysis of the Senegalese group. In conclusion, variations in TB transmission were observed among immigrants from different countries and even within national groups, where living conditions have been found to exert a profound impact. These results emphasize the importance of improving social integration of immigrant subjects in order to limit risks of TB transmission in developed countries. PMID:19832707

  6. Turning off the tap: stopping tuberculosis transmission through active case-finding and prompt effective treatment.

    PubMed

    Yuen, Courtney M; Amanullah, Farhana; Dharmadhikari, Ashwin; Nardell, Edward A; Seddon, James A; Vasilyeva, Irina; Zhao, Yanlin; Keshavjee, Salmaan; Becerra, Mercedes C

    2015-12-01

    To halt the global tuberculosis epidemic, transmission must be stopped to prevent new infections and new cases. Identification of individuals with tuberculosis and prompt initiation of effective treatment to rapidly render them non-infectious is crucial to this task. However, in settings of high tuberculosis burden, active case-finding is often not implemented, resulting in long delays in diagnosis and treatment. A range of strategies to find cases and ensure prompt and correct treatment have been shown to be effective in high tuberculosis-burden settings. The population-level effect of targeted active case-finding on reducing tuberculosis incidence has been shown by studies and projected by mathematical modelling. The inclusion of targeted active case-finding in a comprehensive epidemic-control strategy for tuberculosis should contribute substantially to a decrease in tuberculosis incidence. PMID:26515675

  7. Tuberculosis in domestic livestock: pathogenesis, transmission, and vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mycobacterium tuberculosis complex includes agents such as M. tuberculosis and M. bovis, the cause of tuberculosis in most animals and a zoonotic pathogen. Mycobacterium bovis has one of the broadest host ranges of any pathogen, infecting most mammals, including humans. Models are used to study ...

  8. The Impact of Ventilation and Early Diagnosis on Tuberculosis Transmission in Brazilian Prisons.

    PubMed

    Urrego, Juliana; Ko, Albert I; da Silva Santos Carbone, Andrea; Paião, Dayse Sanchez Guimarães; Sgarbi, Renata Viebrantz Enne; Yeckel, Catherine W; Andrews, Jason R; Croda, Julio

    2015-10-01

    Prisoners have among the highest incidence of tuberculosis (TB) globally. However, the contribution of the prison environment on transmission is not well understood and structural characteristics have received little attention as effective epidemiological interventions in TB control. We evaluated architectural characteristics and estimated ventilation rates in 141 cells in three prisons in central west Brazil using steady-state exhaled carbon dioxide (CO2) levels. We used a modified Wells-Riley equation to estimate the probability of infection for inmates sharing a cell with an infectious case and projected the impact of interventions, including early diagnosis and improved ventilation. Overall, prison cells were densely populated (mean 2.1 m(2) per occupant) and poorly ventilated, with only three cells meeting World Health Organization (WHO) standards for per-person ventilation (60 L/s) applied in infection control settings. In the absence of interventions, projected mean risk of infection was 78.0% during a 6-month period. Decreasing time-to-diagnosis by 25% reduced transmission risk by 8.3%. Improving ventilation to WHO standards decreased transmission by 38.2%, whereas optimizing cross-ventilation reduced transmission by 64.4%. Prison environments promote high infection risk over short-time intervals. In this context, enhanced diagnostics have a limited impact on reducing transmission. Improving natural ventilation may be required to effectively control TB in prisons. PMID:26195459

  9. Mycobacterium tuberculosis infection as a zoonotic disease: transmission between humans and elephants.

    PubMed Central

    Michalak, K.; Austin, C.; Diesel, S.; Bacon, M. J.; Zimmerman, P.; Maslow, J. N.

    1998-01-01

    Between 1994 and 1996, three elephants from an exotic animal farm in Illinois died of pulmonary disease due to Mycobacterium tuberculosis. In October 1996, a fourth living elephant was culture-positive for M. tuberculosis. Twenty-two handlers at the farm were screened for tuberculosis (TB); eleven had positive reactions to intradermal injection with purified protein derivative. One had smear-negative, culture-positive active TB. DNA fingerprint comparison by IS6110 and TBN12 typing showed that the isolates from the four elephants and the handler with active TB were the same strain. This investigation indicates transmission of M. tuberculosis between humans and elephants. PMID:9621200

  10. Tuberculosis cross-species transmission in Tanzania: towards a One-Health concept.

    PubMed

    Mbugi, Erasto V; Katale, Bugwesa Z; Kendall, Sharon; Good, Liam; Kibiki, Gibson S; Keyyu, Julius D; Godfrey-Faussett, Peter; Van Helden, Paul; Matee, Mecky I

    2012-01-01

    For centuries, tuberculosis, which is a chronic infection caused by the bacillus Mycobacterium tuberculosis has remained a global health problem. The global burden of tuberculosis has increased, particularly in the Southern African region, mainly due to HIV, and inadequate health systems which has in turn given rise to emergent drug resistant tuberculosis (TB) strains. Bovine tuberculosis (BTB) has also emerged as a significant disease with the tendency for inter-species spread. The extent of interspecies BTB transmission both in urban and rural communities has not been adequately assessed. The phenomenon is of particular importance in rural communities where people share habitats with livestock and wildlife (particularly in areas near national parks and game reserves). Aerosol and oral intake are the major routes of transmission from diseased to healthy individuals, with health care workers often contracting infection nosocomially. Although TB control has increasingly been achieved in high-income countries, the disease, like other poverty-related infections, has continued to be a disaster in countries with low income economies. Transmission of infections occurs not only amongst humans but also between animals and humans (and occasionally vice versa) necessitating assessment of the extent of transmission at their interface. This review explores tuberculosis as a disease of humans which can cross-transmit between humans, livestock and wildlife. The review also addresses issues underlying the use of molecular biology, genetic sequencing and bioinformatics as t tools to understand the extent of inter-species cross-transmission of TB in a 'One Health' context. PMID:23327386

  11. Transmission of multidrug-resistant tuberculosis in the USA: a cross-sectional study

    PubMed Central

    Moonan, Patrick K; Teeter, Larry D; Salcedo, Katya; Ghosh, Smita; Ahuja, Shama D; Flood, Jennifer; Graviss, Edward A

    2015-01-01

    Summary Background Multidrug-resistant (MDR) tuberculosis is a potential threat to tuberculosis elimination, but the extent of MDR tuberculosis disease in the USA that is attributable to transmission within the country is unknown. We assessed transmission of MDR tuberculosis and potential contributing factors in the USA. Methods In a cross-sectional study, clinical, demographic, epidemiological, and Mycobacterium tuberculosis genotype data were obtained during routine surveillance of all verified cases of MDR tuberculosis reported from eight states in the USA (California from Jan 1, 2007, to Dec 31, 2009; Texas from Jan 1, 2007, to March 31, 2009; and the states of Colorado, Maryland, Massachusetts, New York, Tennessee, and Washington from Jan 1, 2007 to Dec 31, 2008). In-depth interviews and health-record abstraction were done for all who consented to ascertain potential interpersonal connections. Findings 168 cases of MDR tuberculosis were reported in the eight states during our study period. 92 individuals (55%) consented to in-depth interview. 20 (22%) of these individuals developed MDR tuberculosis as a result of transmission in the USA; a source case was identified for eight of them (9%). 20 individuals (22%) had imported active tuberculosis (ie, culture-confirmed disease within 3 months of entry into the USA). 38 (41%) were deemed to have reactivation of disease, of whom 14 (15%) had a known previous episode of tuberculosis outside the USA. Five individuals (5%) had documented treatment of a previous episode in the USA, and so were deemed to have relapsed. For nine cases (10%), insufficient evidence was available to definitively classify reason for presentation. Interpretation About a fifth of cases of MDR tuberculosis in the USA can be linked to transmission within the country. Many individuals acquire MDR tuberculosis before entry into the USA. MDR tuberculosis needs to be diagnosed rapidly to reduce potential infectious periods, and clinicians should

  12. Prisons as reservoir for community transmission of tuberculosis, Brazil.

    PubMed

    Sacchi, Flávia P C; Praça, Renata M; Tatara, Mariana B; Simonsen, Vera; Ferrazoli, Lucilaine; Croda, Mariana G; Suffys, Philip N; Ko, Albert I; Andrews, Jason R; Croda, Julio

    2015-03-01

    We conducted a population-based study of tuberculosis (TB) cases in Dourados, Brazil, to assess the relationship between incarceration and TB in the general population. Incarceration was associated with TB in an urban population; 54% of Mycobacterium tuberculosis strains were related to strains from persons in prisons. TB control in prisons is critical for reducing disease prevalence. PMID:25642998

  13. Prisons as Reservoir for Community Transmission of Tuberculosis, Brazil

    PubMed Central

    Sacchi, Flávia P.C.; Praça, Renata M.; Tatara, Mariana B.; Simonsen, Vera; Ferrazoli, Lucilaine; Croda, Mariana G.; Suffys, Philip N.; Ko, Albert I.; Andrews, Jason R.

    2015-01-01

    We conducted a population-based study of tuberculosis (TB) cases in Dourados, Brazil, to assess the relationship between incarceration and TB in the general population. Incarceration was associated with TB in an urban population; 54% of Mycobacterium tuberculosis strains were related to strains from persons in prisons. TB control in prisons is critical for reducing disease prevalence. PMID:25642998

  14. Using rainfall estimates to predict malaria transmission

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-05-01

    Malaria kills nearly a million people each year, mostly in rural Africa. The disease is spread by mosquitoes, which thrive in wet areas, so malaria transmission is closely linked to rainfall. Rainfall estimates could therefore be used to help predict potential malaria transmission. However, rain gauge networks are sparse in many of the rural areas that are hit hardest by malaria.

  15. Knowledge and perception on tuberculosis transmission in Tanzania: Multinomial logistic regression analysis of secondary data.

    PubMed

    Ismail, Abbas; Josephat, Peter

    2014-01-01

    Tuberculosis (TB) is one of the most important public health problems in Tanzania and was declared as a national public health emergency in 2006. Community and individual knowledge and perceptions are critical factors in the control of the disease. The objective of this study was to analyze the knowledge and perception on the transmission of TB in Tanzania. Multinomial Logistic Regression analysis was considered in order to quantify the impact of knowledge and perception on TB. The data used was adopted as secondary data from larger national survey 2007-08 Tanzania HIV/AIDS and Malaria Indicator Survey. The findings across groups revealed that knowledge on TB transmission increased with an increase in age and level of education. People in rural areas had less knowledge regarding tuberculosis transmission compared to urban areas [OR = 0.7]. People with the access to radio [OR = 1.7] were more knowledgeable on tuberculosis transmission compared to those who did not have access to radio. People who did not have telephone [OR = 0.6] were less knowledgeable on tuberculosis route of transmission compared to those who had telephone. The findings showed that socio-demographic factors such as age, education, place of residence and owning telephone or radio varied systematically with knowledge on tuberculosis transmission. PMID:26867270

  16. Effect of Active Case Finding on Prevalence and Transmission of Pulmonary Tuberculosis in Dhaka Central Jail, Bangladesh

    PubMed Central

    Banu, Sayera; Rahman, Md. Toufiq; Uddin, Mohammad Khaja Mafij; Khatun, Razia; Khan, Md. Siddiqur Rahman; Rahman, Md. Mojibur; Uddin, Syed Iftekhar; Ahmed, Tahmeed; Heffelfinger, James D.

    2015-01-01

    Background Understanding tuberculosis (TB) transmission dynamics is essential for establishing effective TB control strategies in settings where the burden and risk of transmission are high. The objectives of this study were to evaluate the effect of active screening on controlling TB transmission and also to characterize Mycobacterium tuberculosis strains for investigating transmission dynamics in a correctional setting. Methods The study was carried out in Dhaka Central Jail (DCJ), from October 2005 to February 2010. An active case finding strategy for pulmonary TB was established both at the entry point to the prison and inside the prison. Three sputum specimens were collected from all pulmonary TB suspects and subjected to smear microscopy, culture, and drug susceptibility testing as well as genotyping which included deletion analysis, spoligotyping and analysis of mycobacterial interspersed repetitive units (MIRU). Results A total of 60,585 inmates were screened during the study period. We found 466 inmates with pulmonary TB of whom 357 (77%) had positive smear microscopy results and 109 (23%) had negative smear microscopy results but had positive results on culture. The number of pulmonary TB cases declined significantly, from 49 cases during the first quarter to 8 cases in the final quarter of the study period (p=0.001). Deletion analysis identified all isolates as M. tuberculosis and further identified 229 (70%) strains as ‘modern’ and 100 (30%) strains as ‘ancestral’. Analysis of MIRU showed that 347 strains (85%) exhibited unique patterns, whereas 61 strains (15%) clustered into 22 groups. The largest cluster comprised eight strains of the Beijing M. tuberculosis type. The rate of recent transmission was estimated to be 9.6%. Conclusions Implementation of active screening for TB was associated with a decline in TB cases in DCJ. Implementation of active screening in prison settings might substantially reduce the national burden of TB in Bangladesh

  17. Mathematical model for transmission of tuberculosis in badger population with vaccination

    NASA Astrophysics Data System (ADS)

    Tasmi, Aldila, D.; Soewono, E.; Nuraini, N.

    2016-04-01

    Badger was first time identified as a carrier of Bovine tuberculosis disease in England since 30 years ago. Bovine tuberculosis can be transmitted to another species through the faces, saliva, and breath. The control of tuberculosis in the badger is necessary to reduce the spread of the disease to other species. Many actions have been taken by the government to tackle the disease such as culling badgers with cyanide gas, but this way destroys the natural balance and disrupts the badger population. An alternative way to eliminate tuberculosis within badger population is by vaccination. Here in this paper a model for transmission of badger tuberculosis with vaccination is discussed. The existence of the endemic equilibrium, the stability and the basic reproduction ratio are shown analytically. Numerical simulations show that with proper vaccination level, the basic reproduction ratio could be reduced significantly. Sensitivity analysis for variation of parameters are shown numerically.

  18. Heterogeneity in tuberculosis transmission and the role of geographic hotspots in propagating epidemics

    PubMed Central

    Dowdy, David W.; Golub, Jonathan E.; Chaisson, Richard E.; Saraceni, Valeria

    2012-01-01

    The importance of high-incidence “hotspots” to population-level tuberculosis (TB) incidence remains poorly understood. TB incidence varies widely across countries, but within smaller geographic areas (e.g., cities), TB transmission may be more homogeneous than other infectious diseases. We constructed a steady-state compartmental model of TB in Rio de Janeiro, replicating nine epidemiological variables (e.g., TB incidence) within 1% of their observed values. We estimated the proportion of TB transmission originating from a high-incidence hotspot (6.0% of the city’s population, 16.5% of TB incidence) and the relative impact of TB control measures targeting the hotspot vs. the general community. If each case of active TB in the hotspot caused 0.5 secondary transmissions in the general community for each within-hotspot transmission, the 6.0% of people living in the hotspot accounted for 35.3% of city-wide TB transmission. Reducing the TB transmission rate (i.e., number of secondary infections per infectious case) in the hotspot to that in the general community reduced city-wide TB incidence by 9.8% in year 5, and 29.7% in year 50—an effect similar to halving time to diagnosis for the remaining 94% of the community. The importance of the hotspot to city-wide TB control depended strongly on the extent of TB transmission from the hotspot to the general community. High-incidence hotspots may play an important role in propagating TB epidemics. Achieving TB control targets in a hotspot containing 6% of a city’s population can have similar impact on city-wide TB incidence as achieving the same targets throughout the remaining community. PMID:22645356

  19. Tuberculosis.

    PubMed

    Tiruviluamala, Parvathi; Reichman, Lee B

    2002-01-01

    Tuberculosis is an infectious disease caused by bacteria in the Mycobacterium tuberculosis complex. Of these, the most common species to infect humans is M. tuberculosis. The TB bacillus is an extremely successful human pathogen, infecting two billion persons worldwide; an estimated 2 to 3 million people die from tuberculosis each year. In the United States, TB rates decreased steadily at the rate of 5% per year from 1953 until 1985 when the trend reversed, with the number of TB cases peaking in 1992. Outbreaks of multidrug-resistant TB (MDR TB) were reported, and these cases were documented to be transmitted in nosocomial and congregate settings, including hospitals and prisons. AIDS patients infected with M. tb developed disease rapidly, and case-fatality rates of >80% were noted in those infected with multidrug-resistant M. tb. Intensive intervention, at enormous cost, caused the number of TB cases to decline. This article discusses factors that led to the increase in TB cases, their subsequent decline, and measures needed in the future if TB is to be eliminated in the United States. PMID:11910069

  20. Tuberculosis transmission to young children in a South African community: modeling household and community infection risks

    PubMed Central

    Wood, Robin; Johnstone-Robertson, Simon; Uys, Pieter; Hargrove, John; Middelkoop, Keren; Lawn, Stephen D.; Bekker, Linda-Gail

    2011-01-01

    Introduction Tuberculosis (TB) transmission is determined by contact between infectious and susceptible individuals. A recent study reported a 4% annual risk of child TB infection (ARTI) in a Southern African township. A model was used to explore the interactions between prevalence of adult TB infection, adult-to-child contacts and household ventilation which could result in such a high ARTI. Methods Number of residents per household and TB incidence were derived from a household census and community TB registers. Using the “Wells-Riley” equation and probability analyses of contact between TB infectious adults and pre-school children, we estimated the ARTI within and outside of the home. Results There was a mean of 2.2 adults per child-household with a 1.35% annual adult smear-positive TB notification rate. The maximal household ARTI was 3% which was primarily determined by the number of resident adults. Transmission risk outside the home increased with numbers of households visited. Transmission probabilities were sensitive to exposure time, ventilation and period of adult infectivity. The benefits of increased ventilation were greatest when the period of infectivity was reduced. Similar reductions in household transmission could be achieved by increasing ventilation from 2 to 6 air changes/hour or separating child and adult sleeping areas. Conclusions The ARTI of pre-school children predominantly results from infectious residents in the home. However, even with limited social interactions, a substantial proportion of transmission may occur from non-resident adults. The benefits of increased ventilation are maximized when the period of infectivity is reduced by prompt treatment of source cases. PMID:20604716

  1. Predominance of modern Mycobacterium tuberculosis strains and active transmission of Beijing sublineage in Jayapura, Indonesia Papua.

    PubMed

    Chaidir, Lidya; Sengstake, Sarah; de Beer, Jessica; Oktavian, Antonius; Krismawati, Hana; Muhapril, Erfin; Kusumadewi, Inri; Annisa, Jessi; Anthony, Richard; van Soolingen, Dick; Achmad, Tri Hanggono; Marzuki, Sangkot; Alisjahbana, Bachti; van Crevel, Reinout

    2016-04-01

    Mycobacterium tuberculosis genotype distribution is different between West and Central Indonesia, but there are no data on the most Eastern part, Papua. We aimed to identify the predominant genotypes of M. tuberculosis responsible for tuberculosis in coastal Papua, their transmission, and the association with patient characteristics. A total of 199 M. tuberculosis isolates were collected. Spoligotyping was applied to describe the population structure of M. tuberculosis, lineage identification was performed using a combination of lineage-specific markers, and genotypic clusters were identified using a combination of 24-locus-MIRU-VNTR and spoligotyping. A high degree of genetic diversity was observed among isolates based on their spoligopatterns. Strains from modern lineage 4 made up almost half of strains (46.9%), being more abundant than the ancient lineage 1 (33.7%), and modern lineage 2 (19.4%). Thirty-five percent of strains belonged to genotypic clusters, especially strains in the Beijing genotype. Previous TB treatment and mutations associated with drug resistance were more common in patients infected with strains of the Beijing genotype. Papua shows a different distribution of M. tuberculosis genotypes compared to other parts of Indonesia. Clustering and drug resistance of modern strains recently introduced to Papua may contribute to the high tuberculosis burden in this region. PMID:26825253

  2. Unsuspected and extensive transmission of a drug-susceptible Mycobacterium tuberculosis strain

    PubMed Central

    López-Calleja, Ana Isabel; Gavín, Patricia; Lezcano, Ma Antonia; Vitoria, Ma Asunción; Iglesias, Ma José; Guimbao, Joaquín; Lázaro, Ma Ángeles; Rastogi, Nalin; Revillo, Ma José; Martín, Carlos; Samper, Sofia

    2009-01-01

    Background A large and unsuspected tuberculosis outbreak involving 18.7% of the total of the tuberculosis cases studied, was detected in a population-based molecular epidemiological study performed in Zaragoza (Spain) from 2001 to 2004. Methods The Mycobacterium tuberculosis drug-susceptible strain, named MTZ strain, was genetically characterized by IS6110-RFLP, Spoligotyping and by MIRU-VNTR typing and the genetic patterns obtained were compared with those included in international databases. The characteristics of the affected patients, in an attempt to understand why the MTZ strain was so highly transmitted among the population were also analyzed. Results The genetic profile of the MTZ strain was rare and not widely distributed in our area or elsewhere. The patients affected did not show any notable risk factor for TB. Conclusion The M. tuberculosis strain MTZ, might have particular transmissibility or virulence properties, and we believe that greater focus should be placed on stopping its widespread dissemination. PMID:19144198

  3. Transmission and Progression to Disease of Mycobacterium tuberculosis Phylogenetic Lineages in The Netherlands

    PubMed Central

    Verhagen, Lilly M.; Borgdorff, Martien W.; van Soolingen, Dick

    2015-01-01

    The aim of this study was to determine if mycobacterial lineages affect infection risk, clustering, and disease progression among Mycobacterium tuberculosis cases in The Netherlands. Multivariate negative binomial regression models adjusted for patient-related factors and stratified by patient ethnicity were used to determine the association between phylogenetic lineages and infectivity (mean number of positive contacts around each patient) and clustering (as defined by number of secondary cases within 2 years after diagnosis of an index case sharing the same fingerprint) indices. An estimate of progression to disease by each risk factor was calculated as a bootstrapped risk ratio of the clustering index by the infectivity index. Compared to the Euro-American reference, Mycobacterium africanum showed significantly lower infectivity and clustering indices in the foreign-born population, while Mycobacterium bovis showed significantly lower infectivity and clustering indices in the native population. Significantly lower infectivity was also observed for the East African Indian lineage in the foreign-born population. Smear positivity was a significant risk factor for increased infectivity and increased clustering. Estimates of progression to disease were significantly associated with age, sputum-smear status, and behavioral risk factors, such as alcohol and intravenous drug abuse, but not with phylogenetic lineages. In conclusion, we found evidence of a bacteriological factor influencing indicators of a strain's transmissibility, namely, a decreased ability to infect and a lower clustering index in ancient phylogenetic lineages compared to their modern counterparts. Confirmation of these findings via follow-up studies using tuberculin skin test conversion data should have important implications on M. tuberculosis control efforts. PMID:26224845

  4. Impact of HIV co-infection on the evolution and transmission of multidrug-resistant tuberculosis.

    PubMed

    Eldholm, Vegard; Rieux, Adrien; Monteserin, Johana; Lopez, Julia Montana; Palmero, Domingo; Lopez, Beatriz; Ritacco, Viviana; Didelot, Xavier; Balloux, Francois

    2016-01-01

    The tuberculosis (TB) epidemic is fueled by a parallel Human Immunodeficiency Virus (HIV) epidemic, but it remains unclear to what extent the HIV epidemic has been a driver for drug resistance in Mycobacterium tuberculosis (Mtb). Here we assess the impact of HIV co-infection on the emergence of resistance and transmission of Mtb in the largest outbreak of multidrug-resistant TB in South America to date. By combining Bayesian evolutionary analyses and the reconstruction of transmission networks utilizing a new model optimized for TB, we find that HIV co-infection does not significantly affect the transmissibility or the mutation rate of Mtb within patients and was not associated with increased emergence of resistance within patients. Our results indicate that the HIV epidemic serves as an amplifier of TB outbreaks by providing a reservoir of susceptible hosts, but that HIV co-infection is not a direct driver for the emergence and transmission of resistant strains. PMID:27502557

  5. Tuberculosis

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Tuberculosis KidsHealth > For Teens > Tuberculosis Print A A A Text Size What's in ... Duration When to Call the Doctor en español Tuberculosis TB Basics Tuberculosis (also known as "TB") is ...

  6. A VSEIR model for transmission of tuberculosis (TB) disease in North Sumatera, Indonesia

    NASA Astrophysics Data System (ADS)

    Rangkuti, Yulita M.; Sinaga, Marlina S.; Marpaung, F.; Side, Syafruddin

    2014-12-01

    In this work, Vaccination (V), Susceptible (S) Infected (I), and Recovered (R) (VSIR) model for transmission of Tuberculosis in North Sumatera is modified. An exposed class is adopted to VSIR model so called VSEIR to determine the probability of people who infectious before infected. This model is written in ordinary differential equation (ODEs) in five classes. Determination the equilibrium point and stability analysis of the model is discussed to determine the dynamic behaviour of systems. A simulation is also discussed to see the suitable model to North Sumatera data. The simulation of VSEIR model indicates Tuberculosis has not endemic in North Sumatera.

  7. Transmission of Tuberculosis in Resource-Limited Settings

    PubMed Central

    Kompala, Tejaswi; Shenoi, Sheela V.; Friedland, Gerald

    2013-01-01

    Unrecognized transmission is a major contributor to ongoing TB epidemics in high-burden, resource-constrained settings. Limitations in diagnosis, treatment, and infection control in health-care and community settings allow for continued transmission of drug-sensitive and drug-resistant TB, particularly in regions of high HIV prevalence. Health-care facilities are common sites of TB transmission. Improved implementation of infection control practices appropriate for the local setting and in combination, has been associated with reduced transmission. Community settings account for the majority of TB transmission and deserve increased focus. Strengthening and intensifying existing high-yield strategies, including household contact tracing, can reduce onward TB transmission. Recent studies documenting high transmission risk community sites and strategies for community-based intensive case finding hold promise for feasible, effective transmission reduction. Infection control in community settings has been neglected and requires urgent attention. Developing and implementing improved strategies for decreasing transmission to children, within prisons and of drug-resistant TB are needed. PMID:23824469

  8. Chest Radiographic Patterns and the Transmission of Tuberculosis: Implications for Automated Systems

    PubMed Central

    Lau, Angela; Barrie, James; Winter, Christopher; Elamy, Abdel-Halim; Tyrrell, Gregory; Long, Richard

    2016-01-01

    Background Computer-aided detection to identify and diagnose pulmonary tuberculosis is being explored. While both cavitation on chest radiograph and smear-positivity on microscopy are independent risk factors for the infectiousness of pulmonary tuberculosis it is unknown which radiographic pattern, were it detectable, would provide the greatest public health benefit; i.e. reduced transmission. Herein we provide that evidence. Objectives 1) to determine whether pulmonary tuberculosis in a high income, low incidence country is more likely to present with “typical” adult-type pulmonary tuberculosis radiographic features and 2) to determine whether those with “typical” radiographic features are more likely than those without such features to transmit the organism and/or cause secondary cases. Methods Over a three-year period beginning January 1, 2006 consecutive adults with smear-positive pulmonary tuberculosis in the Province of Alberta, Canada, were identified and their pre-treatment radiographs scored by three independent readers as “typical” (having an upper lung zone predominant infiltrate, with or without cavitation but no discernable adenopathy) or “atypical” (all others). Each patient’s pre-treatment bacillary burden was carefully documented and, during a 30-month transmission window, each patient’s transmission events were recorded. Mycobacteriology, radiology and transmission were compared in those with “typical” versus “atypical” radiographs. Findings A total of 97 smear-positive pulmonary tuberculosis cases were identified, 69 (71.1%) with and 28 (28.9%) without “typical” chest radiographs. “Typical” cases were more likely to have high bacillary burdens and cavitation (Odds Ratios and 95% Confidence Intervals: 2.75 [1.04–7.31] and 9.10 [2.51–32.94], respectively). Typical cases were also responsible for most transmission events—78% of tuberculin skin test conversions (p<0.002) and 95% of secondary cases in reported

  9. [Evaluation of tuberculosis detection indicators in a region with high risk of transmission in Peru].

    PubMed

    Roque-Henríquez, Joel; Catacora-López, Fresia; Hilasaca-Yungas, Gladys; Romaní-Romaní, Franco

    2015-01-01

    An operational study was conducted to evaluate the tuberculosis detection indicators established in the Technical Standard for Comprehensive Care of Persons Affected by Tuberculosis. Three networks of first level of care facilities with very high risk of tuberculosis transmission from the Tacna region were selected. Using the registry of respiratory symptomatic patients, we analyzed 14,595 respiratory symptomatic subjects (RSS), of which we examined (ExRSS) 14,486 (99.3%). Of the total of ExRSS, 1.5% were BK (+).The average direct smears per RSS was 2.0 and search intensity (ratio between RSS and number of health care visits in more than 15 years) was 2.8%. Males were more likely to have at least one positive smear compared to women, OR 2.0 (95% CI: 1.5 to 2.6). It is concluded that the diagnostic performance of direct smears in respiratory symptomatic subjects is low. PMID:26580933

  10. TRANSMISSION AND RISK FACTORS FOR LATENT TUBERCULOSIS INFECTIONS AMONG INDEX CASE-MATCHED HOUSEHOLD CONTACTS.

    PubMed

    Faksri, Kiatichai; Reechaipichitkul, Wipa; Pimrin, Wilailuk; Bourpoern, Janpen; Prompinij, Supapim

    2015-05-01

    An understanding of the risk factors associated with acquiring and transmitting Mycobacterium tuberculosis (MTB) is required for controlling tuberculosis (TB). We aimed to determine the risk factors and transmission factors for latent tuberculosis infection (LTBI) in northeastern Thailand. Household contact persons (n = 70) and matched index patients with pulmonary TB (n = 42) who presented to Srinagarind Hospital, Khon Kaen, Thailand were interviewed from September 1, 2012 to March 31, 2014. LTBI was determined by positive results on both a tuberculin skin test and the QuantiFERON-TB Gold In-Tube test. Multivariate analysis of host and environmental risk factors was performed. Among contact persons, being aged 20 years (adjusted OR=14.0; 95% CI: 1.2-159.5), having a family relationship with a TB subject such as being a spouse or parent (adjusted OR=24.9; 95% CI: 2.4-263.9) and exposure to a TB subject for 5 hours/day (adjusted OR=9.2; 95% CI: 1.4-58.1) were risk factors for LTBI. Having a high bacillary load (adjusted OR=2; 95% CI: 1.26-3.17) or a moderate bacillary load (adjusted OR=1.39; 95% CI: 1.04-1.84) among TB subjects correlated with increased transmissibility compared to having a low bacillary load. The type of dwelling and density of household members were not found to be risk factors for LTBI in our study. We conclude being aged 20 years and having a relationship with a TB patient as a spouse or parent were risk factors for acquiring LTBI, and having a higher bacillary load was a risk factor for transmitting TB. Keywords: latent tuberculosis infection, transmission factor, risk factor, Mycobacterium tuberculosis, interferon-gamma release assay, Thailand PMID:26521523

  11. Tuberculosis

    MedlinePlus

    Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but they can also damage other parts of the body. TB spreads through the air when a person with ...

  12. Shared Air: A Renewed Focus on Ventilation for the Prevention of Tuberculosis Transmission

    PubMed Central

    Richardson, Eugene T.; Morrow, Carl D.; Kalil, Darryl B.; Bekker, Linda-Gail; Wood, Robin

    2014-01-01

    Background Despite an improvement in the overall TB cure rate from 40–74% between 1995 and 2011, TB incidence in South Africa continues to increase. The epidemic is notably disquieting in schools because the vulnerable population is compelled to be present. Older learners (age 15–19) are at particular risk given a smear-positive rate of 427 per 100,000 per year and the significant amount of time they spend indoors. High schools are therefore important locations for potential TB infection and thus prevention efforts. Methods and Findings Using portable carbon dioxide monitors, we measured CO2 in classrooms under non-steady state conditions. The threshold for tuberculosis transmission was estimated using a carbon dioxide-based risk equation. We determined a critical rebreathed fraction of carbon dioxide () of 1·6%, which correlates with an indoor CO2 concentration of 1000 ppm. These values correspond with a ventilation rate of 8·6 l/s per person or 12 air exchanges per hour (ACH) for standard classrooms of 180 m3. Conclusions Given the high smear positive rate of high-school adolescents in South Africa, the proposal to achieve CO2 levels of 1000ppm through natural ventilation (in the amount 12 ACH) will not only help achieve WHO guidelines for providing children with healthy indoor environments, it will also provide a low-cost intervention for helping control the TB epidemic in areas of high prevalence. PMID:24804707

  13. Use of genomics to track bovine tuberculosis transmission.

    PubMed

    Kao, R R; Price-Carter, M; Robbe-Austerman, S

    2016-04-01

    The control of any infectious disease of livestock is made more difficult by the presence of a wildlife reservoir, as the reservoir is often poorly observed and difficult to manage. This problem is particularly acute for bovine tuberculosis (bTB) because the long duration of infection and low levels of infectiousness make tracing the sources of infection difficult. For over 30 years, the process of contact tracing has been aided by the exploitation of molecular markers in the pathogen, but this has largely only been capable of characterising broad associations between large communities of similar types. However, the recent advent of mass high-throughput 'whole-genome' sequencing (WGS) has revolutionised forensic epidemiology for other diseases, and now it has the potential to do so for bTB. In this review, the authors consider the historical context of WGS use and look at what prior molecular techniques have already achieved. They outline the key approaches to interpreting WGS data and consider both the role of advanced analytical techniques that exploit the evolutionary and epidemiological properties of the system and the problems associated with quantifying the role of hidden reservoirs of disease. Finally, they consider the particular difficulties associated with developing this technology for routine diagnostics and its potential for mass use. PMID:27217181

  14. Myths and misconceptions about tuberculosis transmission in Ghana

    PubMed Central

    2013-01-01

    Background Myths and misconceptions about TB can serve as a barrier to efforts at reducing stigmatisation of people infected and affected by the disease. Understanding such drivers of myths and misconceptions is important for improving information, education and communication (IEC) efforts of national control and preventive interventions. This study therefore assesses the influence of interaction of spatial, socioeconomic and demographic characteristics on myths and misconceptions. Methods Data was drawn from male (N = 4,546) and female (N = 4,916) files of the 2008 Ghana Demographic and Health Survey. A myth and misconception variable was created from five-related constructs with internal consistency score of r = 0. 8802 for males (inter-item correlation: 0.5951) and for females, r = 0. 0.9312 (inter-item correlation: 0.7303). The Pearson Chi-square was used to test the bivariate relationship between the independent variables and the dependent variable. Logistic regression was subsequently used to explore the factors determining myths and misconceptions of TB transmission. Results Majority of Ghanaians (males: 66.75%; females: 66.13%) did not hold myths and misconceptions about TB transmission. Females resident in the Upper East (aOR = 0.31, CI = 0.17-0.55) and Upper West (aOR = 0.41, CI = 0.24-0.69) and males resident in the Northern (aOR = 0.23, CI = 0.13-0.39) and the Greater Accra (aOR = 0.25, CI = 0.16-0.39) regions were independently associated with no misconceptions about TB transmission. Significant differences were also found in education, ethnicity and age. Conclusion That spatial and other socioeconomic difference exists in myths and misconceptions suggest the need for spatial, socioeconomic and demographic segmentations in IEC on TB. This holds potentials for reaching out to those who are in critical need of information and education on the transmission processes of TB. PMID:24028419

  15. Mycobacterium tuberculosis transmission in a newborn nursery and maternity ward--New York City, 2003.

    PubMed

    2005-12-23

    Evaluating young children recently exposed to airborne Mycobacterium tuberculosis is a public health priority. If infected, children aged <2 years are at high risk for severe tuberculosis (TB) disease (e.g., TB meningitis). In December 2003, infectious pulmonary TB disease was diagnosed in a foreign-born nurse working in the newborn nursery and maternity ward of a New York City hospital (hospital A); the nurse had declined treatment for latent TB infection (LTBI) after testing positive 11 years earlier. An investigation including medical evaluation of contacts in the nursery and maternity ward was conducted by the Bureau of TB Control (BTBC) at the New York City Department of Health and Mental Hygiene, hospital A, and CDC. This report summarizes the results of that investigation, which determined that approximately 1,500 patients had been exposed to the nurse but the majority could not be located for evaluation. Among those who were tested, four infants had positive tuberculin skin test (TST) results, likely attributable to recent transmission of M. tuberculosis. The findings emphasize the difficulty of conducting contact investigations in certain settings and the importance of effective LTBI testing and treatment programs for health-care workers (HCWs) to prevent TB disease and subsequent health-care--associated transmission. PMID:16371943

  16. Impact of HIV co-infection on the evolution and transmission of multidrug-resistant tuberculosis

    PubMed Central

    Eldholm, Vegard; Rieux, Adrien; Monteserin, Johana; Lopez, Julia Montana; Palmero, Domingo; Lopez, Beatriz; Ritacco, Viviana; Didelot, Xavier; Balloux, Francois

    2016-01-01

    The tuberculosis (TB) epidemic is fueled by a parallel Human Immunodeficiency Virus (HIV) epidemic, but it remains unclear to what extent the HIV epidemic has been a driver for drug resistance in Mycobacterium tuberculosis (Mtb). Here we assess the impact of HIV co-infection on the emergence of resistance and transmission of Mtb in the largest outbreak of multidrug-resistant TB in South America to date. By combining Bayesian evolutionary analyses and the reconstruction of transmission networks utilizing a new model optimized for TB, we find that HIV co-infection does not significantly affect the transmissibility or the mutation rate of Mtb within patients and was not associated with increased emergence of resistance within patients. Our results indicate that the HIV epidemic serves as an amplifier of TB outbreaks by providing a reservoir of susceptible hosts, but that HIV co-infection is not a direct driver for the emergence and transmission of resistant strains. DOI: http://dx.doi.org/10.7554/eLife.16644.001 PMID:27502557

  17. Tuberculosis transmission in multiple correctional facilities--Kansas, 2002-2003.

    PubMed

    2004-08-20

    Tuberculosis (TB) is a substantial health concern in correctional facilities; inmates and employees are at high risk, and TB outbreaks can lead to transmission in surrounding communities. The Advisory Council for the Elimination of Tuberculosis (ACET) recommends that all correctional facilities have a written TB infection-control plan (TBICP). In September 2002, after diagnosis of smear-positive pulmonary TB in a prison inmate, the Kansas TB Control Program, with assistance from CDC, initiated a 6-month contact investigation. This report summarizes the results of that investigation, which determined that, while symptomatic for TB, the inmate had resided in three different jails and a state prison, placing hundreds of employees and other inmates at risk for TB infection. The circumstances of this case underscore the need for effective TBICPs to be implemented by trained employees in jails and prisons and for establishment of mechanisms to facilitate information-sharing between correctional facilities and local and state health departments. PMID:15318157

  18. Assessment of Mycobacterium tuberculosis transmission in Oxfordshire, UK, 2007–12, with whole pathogen genome sequences: an observational study

    PubMed Central

    Walker, Timothy M; Lalor, Maeve K; Broda, Agnieszka; Ortega, Luisa Saldana; Morgan, Marcus; Parker, Lynne; Churchill, Sheila; Bennett, Karen; Golubchik, Tanya; Giess, Adam P; Del Ojo Elias, Carlos; Jeffery, Katie J; Bowler, Ian C J W; Laurenson, Ian F; Barrett, Anne; Drobniewski, Francis; McCarthy, Noel D; Anderson, Laura F; Abubakar, Ibrahim; Thomas, H Lucy; Monk, Philip; Smith, E Grace; Walker, A Sarah; Crook, Derrick W

    2015-01-01

    Summary Background Patients born outside the UK have contributed to a 20% rise in the UK’s tuberculosis incidence since 2000, but their effect on domestic transmission is not known. Here we use whole-genome sequencing to investigate the epidemiology of tuberculosis transmission in an unselected population over 6 years. Methods We identified all residents with Oxfordshire postcodes with a Mycobacterium tuberculosis culture or a clinical diagnosis of tuberculosis between Jan 1, 2007, and Dec 31, 2012, using local databases and checking against the national Enhanced Tuberculosis Surveillance database. We used Illumina technology to sequence all available M tuberculosis cultures from identified cases. Sequences were clustered by genetic relatedness and compared retrospectively with contact investigations. The first patient diagnosed in each cluster was defined as the index case, with links to subsequent cases assigned first by use of any epidemiological linkage, then by genetic distance, and then by timing of diagnosis. Findings Although we identified 384 patients with a diagnosis of tuberculosis, country of birth was known for 380 and we sequenced isolates from 247 of 269 cases with culture-confirmed disease. 39 cases were genomically linked within 13 clusters, implying 26 local transmission events. Only 11 of 26 possible transmissions had been previously identified through contact tracing. Of seven genomically confirmed household clusters, five contained additional genomic links to epidemiologically unidentified non-household members. 255 (67%) patients were born in a country with high tuberculosis incidence, conferring a local incidence of 109 cases per 100 000 population per year in Oxfordshire, compared with 3·5 cases per 100 000 per year for those born in low-incidence countries. However, patients born in the low-incidence countries, predominantly UK, were more likely to have pulmonary disease (adjusted odds ratio 1·8 [95% CI 1·2–2·9]; p=0·009), social

  19. Transmission of multidrug-resistant tuberculosis among immunocompromised persons in a correctional system--New York, 1991.

    PubMed

    1992-07-17

    During 1990 and 1991, nosocomial transmission of multidrug-resistant tuberculosis (MDR-TB) was documented in four hospitals in New York and Florida. Subsequently, additional MDR-TB outbreaks have been investigated by CDC. This report summarizes preliminary results of an investigation of transmission of MDR-TB in a correctional facility in New York. PMID:1630427

  20. Importance of Cough and M. tuberculosis Strain Type as Risks for Increased Transmission within Households

    PubMed Central

    Jones-López, Edward C.; Kim, Soyeon; Fregona, Geisa; Marques-Rodrigues, Patricia; Hadad, David Jamil; Molina, Lucilia Pereira Dutra; Vinhas, Solange; Reilly, Nancy; Moine, Stephanie; Chakravorty, Soumitesh; Gaeddert, Mary; Ribeiro-Rodrigues, Rodrigo; Salgame, Padmini; Palaci, Moises; Alland, David; Ellner, Jerrold J.; Dietze, Reynaldo

    2014-01-01

    Rationale The degree to which tuberculosis (TB) is transmitted between persons is variable. Identifying the factors that contribute to transmission could provide new opportunities for TB control. Transmission is influenced by host, bacterial and environmental factors. However, distinguishing their individual effects is problematic because measures of disease severity are tightly correlated, and assessing the virulence of Mycobacterium tuberculosis isolates is complicated by epidemiological and clinical confounders. Objectives To overcome these problems, we investigated factors potentially associated with TB transmission within households. Methods We evaluated patients with smear-positive (≥2+), pulmonary TB and classified M. tuberculosis strains into single nucleotide polymorphism genetic cluster groups (SCG). We recorded index case, household contact, and environmental characteristics and tested contacts with tuberculin skin test (TST) and interferon-gamma release assay. Households were classified as high (≥70% of contacts with TST≥10 mm) and low (≤40%) transmission. We used logistic regression to determine independent predictors. Result From March 2008 to June 2012, we screened 293 TB patients to enroll 124 index cases and their 731 contacts. There were 23 low and 73 high transmission households. Index case factors associated with high transmission were severity of cough as measured by a visual analog cough scale (VACS) and the Leicester Cough Questionnaire (LCQ), and cavitation on chest radiograph. SCG 3b strains tended to be more prevalent in low (27.3%) than in high (12.5%) transmission households (p = 0.11). In adjusted models, only VACS (p<0.001) remained significant. SCG was associated with bilateral disease on chest radiograph (p = 0.002) and marginally associated with LCQ sores (p = 0.058), with group 3b patients having weaker cough. Conclusions We found differential transmission among otherwise clinically similar patients with

  1. Transmission overhaul estimates for partial and full replacement at repair

    NASA Technical Reports Server (NTRS)

    Savage, M.; Lewicki, D. G.

    1991-01-01

    Timely transmission overhauls increase in-flight service reliability greater than the calculated design reliabilities of the individual aircraft transmission components. Although necessary for aircraft safety, transmission overhauls contribute significantly to aircraft expense. Predictions of a transmission's maintenance needs at the design stage should enable the development of more cost effective and reliable transmissions in the future. The frequency is estimated of overhaul along with the number of transmissions or components needed to support the overhaul schedule. Two methods based on the two parameter Weibull statistical distribution for component life are used to estimate the time between transmission overhauls. These methods predict transmission lives for maintenance schedules which repair the transmission with a complete system replacement or repair only failed components of the transmission. An example illustrates the methods.

  2. Standard Genotyping Overestimates Transmission of Mycobacterium tuberculosis among Immigrants in a Low-Incidence Country.

    PubMed

    Stucki, David; Ballif, Marie; Egger, Matthias; Furrer, Hansjakob; Altpeter, Ekkehardt; Battegay, Manuel; Droz, Sara; Bruderer, Thomas; Coscolla, Mireia; Borrell, Sonia; Zürcher, Kathrin; Janssens, Jean-Paul; Calmy, Alexandra; Mazza Stalder, Jesica; Jaton, Katia; Rieder, Hans L; Pfyffer, Gaby E; Siegrist, Hans H; Hoffmann, Matthias; Fehr, Jan; Dolina, Marisa; Frei, Reno; Schrenzel, Jacques; Böttger, Erik C; Gagneux, Sebastien; Fenner, Lukas

    2016-07-01

    Immigrants from regions with a high incidence of tuberculosis (TB) are a risk group for TB in low-incidence countries such as Switzerland. In a previous analysis of a nationwide collection of 520 Mycobacterium tuberculosis isolates from 2000 to 2008, we identified 35 clusters comprising 90 patients based on standard genotyping (24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat [MIRU-VNTR] typing and spoligotyping). Here, we used whole-genome sequencing (WGS) to revisit these transmission clusters. Genome-based transmission clusters were defined as isolate pairs separated by ≤12 single nucleotide polymorphisms (SNPs). WGS confirmed 17/35 (49%) MIRU-VNTR typing clusters; the other 18 clusters contained pairs separated by >12 SNPs. Most transmission clusters (3/4) of Swiss-born patients were confirmed by WGS, as opposed to 25% (4/16) of the clusters involving only foreign-born patients. The overall clustering proportion was 17% (90 patients; 95% confidence interval [CI], 14 to 21%) by standard genotyping but only 8% (43 patients; 95% CI, 6 to 11%) by WGS. The clustering proportion was 17% (67/401; 95% CI, 13 to 21%) by standard genotyping and 7% (26/401; 95% CI, 4 to 9%) by WGS among foreign-born patients and 19% (23/119; 95% CI, 13 to 28%) and 14% (17/119; 95% CI, 9 to 22%), respectively, among Swiss-born patients. Using weighted logistic regression, we found weak evidence of an association between birth origin and transmission (adjusted odds ratio of 2.2 and 95% CI of 0.9 to 5.5 comparing Swiss-born patients to others). In conclusion, standard genotyping overestimated recent TB transmission in Switzerland compared to WGS, particularly among immigrants from regions with a high TB incidence, where genetically closely related strains often predominate. We recommend the use of WGS to identify transmission clusters in settings with a low incidence of TB. PMID:27194683

  3. Tuberculosis.

    PubMed

    Dheda, Keertan; Barry, Clifton E; Maartens, Gary

    2016-03-19

    Although the worldwide incidence of tuberculosis has been slowly decreasing, the global disease burden remains substantial (∼9 million cases and ∼1·5 million deaths in 2013), and tuberculosis incidence and drug resistance are rising in some parts of the world such as Africa. The modest gains achieved thus far are threatened by high prevalence of HIV, persisting global poverty, and emergence of highly drug-resistant forms of tuberculosis. Tuberculosis is also a major problem in health-care workers in both low-burden and high-burden settings. Although the ideal preventive agent, an effective vaccine, is still some time away, several new diagnostic technologies have emerged, and two new tuberculosis drugs have been licensed after almost 50 years of no tuberculosis drugs being registered. Efforts towards an effective vaccine have been thwarted by poor understanding of what constitutes protective immunity. Although new interventions and investment in control programmes will enable control, eradication will only be possible through substantial reductions in poverty and overcrowding, political will and stability, and containing co-drivers of tuberculosis, such as HIV, smoking, and diabetes. PMID:26377143

  4. HIV Infection and Geographically Bound Transmission of Drug-Resistant Tuberculosis, Argentina

    PubMed Central

    López, Beatriz; Ambroggi, Marta; Palmero, Domingo; Salvadores, Bernardo; Gravina, Elida; Mazzeo, Eduardo; Imaz, Susana; Barrera, Lucía

    2012-01-01

    During 2003–2009, the National Tuberculosis (TB) Laboratory Network in Argentina gave 830 patients a new diagnosis of multidrug-resistant (MDR) TB and 53 a diagnosis of extensively drug- resistant (XDR) TB. HIV co-infection was involved in nearly one third of these cases. Strain genotyping showed that 7 major clusters gathered 56% of patients within restricted geographic areas. The 3 largest clusters corresponded to epidemic MDR TB strains that have been undergoing transmission for >10 years. The indigenous M strain accounted for 29% and 40% of MDR and XDR TB cases, respectively. Drug-resistant TB trends in Argentina are driven by spread of a few strains in hotspots where the rate of HIV infection is high. To curb transmission, the national TB program is focusing stringent interventions in these areas by strengthening infection control in large hospitals and prisons, expediting drug resistance detection, and streamlining information-sharing systems between HIV and TB programs. PMID:23092584

  5. Analysis of Changes in Recent Tuberculosis Transmission Patterns after a Sharp Increase in Immigration▿

    PubMed Central

    Iñigo, Jesús; García de Viedma, Darío; Arce, Araceli; Palenque, Elia; Alonso Rodríguez, Noelia; Rodríguez, Elena; Ruiz Serrano, María Jesús; Andrés, Sandra; Bouza, Emilio; Chaves, Fernando

    2007-01-01

    We conducted a population-based molecular epidemiological study of tuberculosis (TB) in Madrid, Spain (2002 to 2004), to define transmission patterns and factors associated with clustering. We particularly focused on examining how the increase in TB cases among immigrants in recent years (2.8% in 1997 to 1999 to 36.2% during the current study) was modifying transmission patterns. Mycobacterium tuberculosis isolates obtained from patients living in nine districts of Madrid (1,459,232 inhabitants) were genotyped. The TB case rate among foreign-born people was three to four times that of Spanish-born people, and the median time from arrival to the onset of treatment was 22.4 months. During the study period, 227 (36.3%) patients were grouped in 64 clusters, and 115 (50.7%) of them were in 21 clusters with mixed Spanish-born and foreign-born patients. Three of the 21 mixed clusters accounted for 21.1% of clustered patients. Twenty-two of 38 (57.9%) immigrants in mixed clusters were infected with TB strains that had already been identified in the native population in 1997 to 1999, including the three most prevalent strains. Factors identified as independent predictors of clustering were homelessness (odds ratio [OR], 2.3; 95% confidence interval [95% CI], 1.2 to 4.5; P = 0.011) and to be born in Spain (OR, 1.8; 95% CI, 1.2 to 2.6; P = 0.002). The results indicated that (i) TB transmission was higher in Spanish-born people, associated mainly with homelessness, (ii) that foreign-born people were much less likely to be clustered, suggesting a higher percentage of infection before arriving in Spain, and (iii) that an extensive transmission between Spanish- and foreign-born populations, caused mainly by autochthonous strains, was taking place in Madrid. PMID:17108076

  6. An evaluation of indices for quantifying tuberculosis transmission using genotypes of pathogen isolates

    PubMed Central

    Tanaka, Mark M; Phong, Renault; Francis, Andrew R

    2006-01-01

    Background Infectious diseases are often studied by characterising the population structure of the pathogen using genetic markers. An unresolved problem is the effective quantification of the extent of transmission using genetic variation data from such pathogen isolates. Methods It is important that transmission indices reflect the growth of the infectious population as well as account for the mutation rate of the marker and the effects of sampling. That is, while responding to this growth rate, indices should be unresponsive to the sample size and the mutation rate. We use simulation methods taking into account both the mutation and sampling processes to evaluate indices designed to quantify transmission of tuberculosis. Results Previously proposed indices generally perform inadequately according to the above criteria, with the partial exception of the recently proposed Transmission-Mutation Index. Conclusion Any transmission index needs to take into account mutation of the marker and the effects of sampling. Simple indices are unlikely to capture the full complexity of the underlying processes. PMID:16756684

  7. Bayesian Estimation of Mixture Models with Prespecified Elements to Compare Drug Resistance in Treatment-Naïve and Experienced Tuberculosis Cases

    PubMed Central

    Izu, Alane; Cohen, Ted; DeGruttola, Victor

    2013-01-01

    We propose a Bayesian approach for estimating branching tree mixture models to compare drug-resistance pathways (i.e. patterns of sequential acquisition of resistance to individual antibiotics) that are observed among Mycobacterium tuberculosis isolates collected from treatment-naïve and treatment-experienced patients. Resistant pathogens collected from treatment-naïve patients are strains for which fitness costs of resistance were not sufficient to prevent transmission, whereas those collected from treatment-experienced patients reflect both transmitted and acquired resistance, the latter of which may or may not be associated with lower transmissibility. The comparison of the resistance pathways constructed from these two groups of drug-resistant strains provides insight into which pathways preferentially lead to the development of multiple drug resistant strains that are transmissible. We apply the proposed statistical methods to data from worldwide surveillance of drug-resistant tuberculosis collected by the World Health Organization over 13 years. PMID:23555210

  8. Who infects whom? Social networks and tuberculosis transmission in wild meerkats.

    PubMed

    Drewe, Julian A

    2010-02-22

    Transmission of infectious diseases is strongly influenced by who contacts whom. Despite the global distribution of tuberculosis (TB) in free-living wild mammal populations, little is known of the mechanisms of social transmission of Mycobacterium bovis between individuals. Here, I use a network approach to examine for correlations between five distinct types of intra- and intergroup social interaction and changes in TB status of 110 wild meerkats (Suricata suricatta) in five social groups over two years. Contrary to predictions, the most socially interactive animals were not at highest risk of acquiring infection, indicating that in addition to contact frequency, the type and direction of interactions must be considered when quantifying disease risk. Within social groups, meerkats that groomed others most were more likely to become infected than individuals who received high levels of grooming. Conversely, receiving, but not initiating, aggression was associated with M. bovis infection. Incidence of intergroup roving by male meerkats was correlated with the rovers themselves subsequently testing TB-positive, suggesting a possible route for transmission of infection between social groups. Exposure time was less important than these social interactions in influencing TB risk. This study represents a novel application of social network analysis using empirical data to elucidate the role of specific interactions in the transmission of an infectious disease in a free-living wild animal population. PMID:19889705

  9. Multi-drug resistant Mycobacterium tuberculosis complex genetic diversity and clues on recent transmission in Punjab, Pakistan.

    PubMed

    Yasmin, Memona; Gomgnimbou, Michel K; Siddiqui, Rubina T; Refrégier, Guislaine; Sola, Christophe

    2014-10-01

    Multi-Drug Resistant Tuberculosis (MDR-TB), i.e. bacilli resistant to rifampicin (RIF) and isoniazid (INH), is a major Public Health concern in Pakistan according to WHO estimates (3.5% and 32% of new and retreated cases, respectively). Previous Pakistanis reports identified a correlation between being MDR and belonging to Beijing or EAI lineages in one study, and belonging to "H4"-Ural Euro-American sublineage in another study. In addition, MDR-TB transmission was suspected in Karachi. We tested MDR characteristics on a Punjab sample of 278 clinical isolates (without selection for Multi-Drug Resistance) including new and retreated cases collected from 2008 to 2012. All samples were characterized by a new, microbead-based method named "TB-SPRINT" (molecular diagnostic including spoligotype identification, and genetic resistance determinants to first-line anti-TB drugs RIF and INH). Isolates from 2011 to 2012 (n=100) were further analyzed using 24-loci MIRU-VNTR. We detected 8.7% MDR isolates (CI95%=[5.0; 12.5]), mainly among CAS lineage that predominates in this central-East region of Pakistan. Out of 20 MDR-TB cases, 12 different TB-SPRINT profiles were identified, limiting the suspicion of MDR-TB transmission. 24 MIRU-VNTR confirmed the unrelatedness of isolates with different TB-SPRINT profiles and discriminated 3 isolates with identical TB-SPRINT profiles. In conclusion, our study did not confirm any of the correlations between Multi-Drug Resistance and lineage or sublineage in Punjab, Pakistan. MDR-TB isolates were diverse indicating that transmission is not pervasive. TB-SPRINT proved useful as a first step for detecting MDR-TB likely transmission events, before more extensive genotyping such as 15 or 24 MIRU-VNTR and thorough epidemiological investigation. PMID:24981519

  10. Tuberculosis

    MedlinePlus

    ... to address TB and HIV coinfection around the world? The President’s U.S. President's Emergency Plan for AIDS ... of those suffering from HIV/AIDS around the world. PEPFAR’s Global Fund to Fight AIDS, Tuberculosis and ...

  11. Modelling the role of multi-transmission routes in the epidemiology of bovine tuberculosis in cattle and buffalo populations.

    PubMed

    Phepa, Patrick B; Chirove, Faraimunashe; Govinder, Keshlan S

    2016-07-01

    A mathematical model that describes the transmission dynamics of bovine tuberculosis (BTB) in both buffalo and cattle populations is proposed. The model incorporates cross-infection and contaminated environment transmission routes. A full analysis of the model is undertaken. The reproduction number of the entire model is comprised of cross-infection and contaminated parameters. This underscores the importance of including both cross-infection and contaminated environment transmission routes. Crucially our simulations suggest that the disease has a more devastating effect on cattle populations than on buffalo populations when all transmission routes are involved. This has important implications for agriculture and tourism. PMID:27105864

  12. Isonicotinic acid hydrazide: an anti-tuberculosis drug inhibits malarial transmission in the mosquito gut.

    PubMed

    Arai, Meiji; Alavi, Yasmene I H; Mendoza, Jacqueline; Billker, Oliver; Sinden, Robert E

    2004-01-01

    We studied the transmission-blocking effect of isonicotinic acid hydrazide (INH), a widely used anti-tuberculosis drug, against Plasmodium gallinaceum and Plasmodium berghei. INH-treatment of infected animals did not inhibit parasite development in the blood of the vertebrate host, but did inhibit exflagellation, ookinete formation, and oocyst development in the mosquito. Oocyst development was inhibited in a dose-dependent manner. The ED(50) in the P. gallinaceum/chicken/Aedes aegypti model and P. berghei/mouse/Anopheles stephensi model was 72 and 109 mg/kg, respectively. In marked contrast, in vitro exflagellation and ookinete development were not directly affected by physiological concentrations of INH. We suggest that INH exerts its inhibitory effects on the mosquito stages of the malaria parasite by an indirect, and at present undefined mechanism. Further elucidation of the mechanism how INH inhibits parasite development specifically on mosquito stages may allow us to identify new targets for malaria control strategy. PMID:15013786

  13. Fitness of drug resistant Mycobacterium tuberculosis and the impact on the transmission among household contacts.

    PubMed

    Morcillo, Nora S; Imperiale, Belén R; Di Giulio, Ángela; Zumárraga, Martín J; Takiff, Howard; Cataldi, Ángel A

    2014-12-01

    There has been an on-going debate on whether the development of drug resistance in Mycobacterium tuberculosis reduces its relative fitness and its ability to cause disease. The aim of this study was to explore this relationship. For this purpose, we evaluated the in vitro growth of clinical isolates and the transmission of the strains within the patients' households. Clinical and epidemiological data from patients in households, drug-susceptibility and genetic patterns of the isolates were collected. BACTEC MGIT 960™ system with the Epicenter™ software was used to perform fitness experiments and calculate the relative fitness (RF) comparing with the H73Rv reference strain. From 39 households, 124 patients and 388 contacts were included. Concerning transmission, 20 Multi drug-resistant (MDR) and 16 drug sensitive (DS) index cases generated 23 and 28 secondary cases, respectively. An average RF drop of 16.7% was found for MDR strains, but only mutations in rpoB codons 531 were associated with reduced fitness. When the strains were transmitted, their RF tended to decrease, and strains with low RF were less frequently transmitted. Within the limitations of this study, the results showed that the decrease in RF was associated to a limited transmission among the households' contacts. PMID:25306497

  14. Knowledge about HIV prevention and transmission among recently diagnosed tuberculosis patients: a cross sectional study

    PubMed Central

    2013-01-01

    Background Patients with Tuberculosis (TB) are a vulnerable group for acquiring HIV infection. Therefore, countries with a concentrated HIV epidemic and high prevalence of TB should provide adequate information about HIV prevention to TB patients. Methods We conducted a cross-sectional study to evaluate the level of knowledge on HIV prevention and transmission among newly diagnosed TB patients in Lima, Peru. The survey evaluated knowledge about HIV infection and prevention and was administered before HIV counseling and blood sampling for HIV testing were performed. Results A total of 171 TB patients were enrolled; mean age was 31.1 years, 101 (59%) were male. The overall mean level of knowledge of HIV was 59%; but the specific mean level of knowledge on HIV transmission and prevention was only 33.3% and 41.5%, respectively. Age and level of education correlated with overall level of knowledge in the multivariate model (P-value: 0.02 and <0.001 respectively). Conclusions The study shows inadequate levels of knowledge about HIV transmission and prevention among newly-diagnosed TB patients in this setting, and underscores the need for implementing educational interventions in this population. PMID:24373517

  15. Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC)

    PubMed Central

    Wood, Robin; Morrow, Carl; Barry, Clifton E.; Bryden, Wayne A.; Call, Charles J.; Hickey, Anthony J.; Rodes, Charles E.; Scriba, Thomas J.; Blackburn, Jonathan; Issarow, Chacha; Mulder, Nicola; Woodward, Jeremy; Moosa, Atica; Singh, Vinayak; Mizrahi, Valerie; Warner, Digby F.

    2016-01-01

    Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose

  16. Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC).

    PubMed

    Wood, Robin; Morrow, Carl; Barry, Clifton E; Bryden, Wayne A; Call, Charles J; Hickey, Anthony J; Rodes, Charles E; Scriba, Thomas J; Blackburn, Jonathan; Issarow, Chacha; Mulder, Nicola; Woodward, Jeremy; Moosa, Atica; Singh, Vinayak; Mizrahi, Valerie; Warner, Digby F

    2016-01-01

    Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose

  17. A close-up on the epidemiology and transmission of multidrug-resistant tuberculosis in Poland.

    PubMed

    Jagielski, T; Brzostek, A; van Belkum, A; Dziadek, J; Augustynowicz-Kopeć, E; Zwolska, Z

    2015-01-01

    Multidrug-resistant tuberculosis (MDR-TB) poses a serious challenge to the global control of the disease. The purpose of this study was to characterize MDR-TB patients from Poland and to determine the extent of MDR-TB disease attributable to recent transmission. The study included all 46 patients diagnosed with MDR-TB in Poland in 2004 and followed up for 6 years (until 2011). For each patient, sociodemographic and clinical characteristics, treatment outcomes, and bacteriological data were collected by the review of medical and laboratory records. Mycobacterium tuberculosis isolates from all patients were characterized using spoligotyping, mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing, IS6110 restriction fragment length polymorphism (RFLP) analysis, and sequencing analysis of drug resistance-associated loci (katG, mabA-inhA, rpoβ, rpsL, and embB). The majority of patients were male (86.9%), 40-64 years of age (60.8%), with a history of TB treatment (84.8%), and producing smear-positive sputa (86.9%). Twenty-two (47.8%) patients suffered from concomitant diseases and 28 (60.8%) were alcohol abusers. Treatment outcome assessment revealed that 8 (17.4%) patients were cured or completed therapy, while 15 (32.6%) died of TB, 11 (23.9%) defaulted, 8 (17.4%) failed, and 1 (2.2%) was transferred and lost to follow-up. Upon genotyping, 10 (21.7%) isolates were allocated in four clusters. These were further subdivided by mutational profiling. Overall, in 6 (13%) patients, MDR-TB was a result of recent transmission. For 4 (8.7%) of these patients, a direct epidemiological link was established. The study shows that the transmission of MDR-TB occurs at a low rate in Poland. Of urgent need is the implementation of a policy of enforced treatment of MDR-TB patients in Poland. PMID:25037868

  18. Estimating parameter of influenza transmission using regularized least square

    NASA Astrophysics Data System (ADS)

    Nuraini, N.; Syukriah, Y.; Indratno, S. W.

    2014-02-01

    Transmission process of influenza can be presented in a mathematical model as a non-linear differential equations system. In this model the transmission of influenza is determined by the parameter of contact rate of the infected host and susceptible host. This parameter will be estimated using a regularized least square method where the Finite Element Method and Euler Method are used for approximating the solution of the SIR differential equation. The new infected data of influenza from CDC is used to see the effectiveness of the method. The estimated parameter represents the contact rate proportion of transmission probability in a day which can influence the number of infected people by the influenza. Relation between the estimated parameter and the number of infected people by the influenza is measured by coefficient of correlation. The numerical results show positive correlation between the estimated parameters and the infected people.

  19. Elucidating Emergence and Transmission of Multidrug-Resistant Tuberculosis in Treatment Experienced Patients by Whole Genome Sequencing

    PubMed Central

    Clark, Taane G.; Mallard, Kim; Coll, Francesc; Preston, Mark; Assefa, Samuel; Harris, David; Ogwang, Sam; Mumbowa, Francis; Kirenga, Bruce; O’Sullivan, Denise M.; Okwera, Alphonse; Eisenach, Kathleen D.; Joloba, Moses; Bentley, Stephen D.; Ellner, Jerrold J.; Parkhill, Julian; Jones-López, Edward C.; McNerney, Ruth

    2013-01-01

    Background Understanding the emergence and spread of multidrug-resistant tuberculosis (MDR-TB) is crucial for its control. MDR-TB in previously treated patients is generally attributed to the selection of drug resistant mutants during inadequate therapy rather than transmission of a resistant strain. Traditional genotyping methods are not sufficient to distinguish strains in populations with a high burden of tuberculosis and it has previously been difficult to assess the degree of transmission in these settings. We have used whole genome analysis to investigate M. tuberculosis strains isolated from treatment experienced patients with MDR-TB in Uganda over a period of four years. Methods and Findings We used high throughput genome sequencing technology to investigate small polymorphisms and large deletions in 51 Mycobacterium tuberculosis samples from 41 treatment-experienced TB patients attending a TB referral and treatment clinic in Kampala. This was a convenience sample representing 69% of MDR-TB cases identified over the four year period. Low polymorphism was observed in longitudinal samples from individual patients (2-15 SNPs). Clusters of samples with less than 50 SNPs variation were examined. Three clusters comprising a total of 8 patients were found with almost identical genetic profiles, including mutations predictive for resistance to rifampicin and isoniazid, suggesting transmission of MDR-TB. Two patients with previous drug susceptible disease were found to have acquired MDR strains, one of which shared its genotype with an isolate from another patient in the cohort. Conclusions Whole genome sequence analysis identified MDR-TB strains that were shared by more than one patient. The transmission of multidrug-resistant disease in this cohort of retreatment patients emphasises the importance of early detection and need for infection control. Consideration should be given to rapid testing for drug resistance in patients undergoing treatment to monitor the

  20. CT scanner x-ray spectrum estimation from transmission measurements

    PubMed Central

    Duan, Xinhui; Wang, Jia; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia H.

    2011-01-01

    Purpose: In diagnostic CT imaging, multiple important applications depend on the knowledge of the x-ray spectrum, including Monte Carlo dose calculations and dual-energy material decomposition analysis. Due to the high photon flux involved, it is difficult to directly measure spectra from the x-ray tube of a CT scanner. One potential method for indirect measurement involves estimating the spectrum from transmission measurements. The expectation maximization (EM) method is an accurate and robust method to solve this problem. In this article, this method was evaluated in a commercial CT scanner. Methods: Two step-wedges (polycarbonate and aluminum) were used to produce different attenuation levels. Transmission measurements were performed on the scanner and the measured data from the scanner were exported to an external computer to calculate the spectra. The EM method was applied to solve the equations that represent the attenuation processes of polychromatic x-ray photons. Estimated spectra were compared to the spectra simulated using a software provided by the manufacturer of the scanner. To test the accuracy of the spectra, a verification experiment was performed using a phantom containing different depths of water. The measured transmission data were compared to the transmission values calculated using the estimated spectra. Results: Spectra of 80, 100, 120, and 140 kVp from a dual-source CT scanner were estimated. The estimated and simulated spectra were well matched. The differences of mean energies were less than 1 keV. In the verification experiment, the measured and calculated transmission values were in excellent agreement. Conclusions: Spectrum estimation using transmission data and the EM method is a quantitatively accurate and robust technique to estimate the spectrum of a CT system. This method could benefit studies relying on accurate knowledge of the x-ray spectra from CT scanner. PMID:21452736

  1. Whole genome sequencing of Mycobacterium tuberculosis for detection of recent transmission and tracing outbreaks: A systematic review.

    PubMed

    Nikolayevskyy, Vlad; Kranzer, Katharina; Niemann, Stefan; Drobniewski, Francis

    2016-05-01

    Contact tracing complemented with genotyping is considered an important means of understanding person-to-person transmission of tuberculosis (TB). It still remains unclear whether Whole Genome Sequencing (WGS) of Mycobacterium tuberculosis can rule in transmission and how it performs in different human populations, risk groups and across TB lineages. This systematic review aimed to determine the sensitivity and specificity of WGS for detection of recent transmission using conventional epidemiology as the gold standard and investigate if WGS identifies previously undetected transmission events. Systematic review was conducted according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses group. A compound search strategy was developed to identify all relevant studies published between 01/01/2005 and 30/11/2014 using three online databases. Publications satisfying specific criteria have been identified and data extracted. A total of 12 publications were included. We established that WGS has a higher discriminatory power compared to conventional genotyping and detects transmission events missed by epidemiological investigations. A cut-off value of <6 SNPs between isolates may predict recent transmission. None of the studies performed a head-to-head comparison between WGS and conventional genotyping using unselected prospectively collected isolates. Minimum reporting criteria for WGS studies have been proposed and quality control parameters considered. PMID:27156621

  2. Identifying Likely Transmission Pathways within a 10-Year Community Outbreak of Tuberculosis by High-Depth Whole Genome Sequencing

    PubMed Central

    Sadsad, Rosemarie; Martinez, Elena; Jelfs, Peter; Hill-Cawthorne, Grant A.; Gilbert, Gwendolyn L.; Marais, Ben J.; Sintchenko, Vitali

    2016-01-01

    Background Improved tuberculosis control and the need to contain the spread of drug-resistant strains provide a strong rationale for exploring tuberculosis transmission dynamics at the population level. Whole-genome sequencing provides optimal strain resolution, facilitating detailed mapping of potential transmission pathways. Methods We sequenced 22 isolates from a Mycobacterium tuberculosis cluster in New South Wales, Australia, identified during routine 24-locus mycobacterial interspersed repetitive unit typing. Following high-depth paired-end sequencing using the Illumina HiSeq 2000 platform, two independent pipelines were employed for analysis, both employing read mapping onto reference genomes as well as de novo assembly, to control biases in variant detection. In addition to single-nucleotide polymorphisms, the analyses also sought to identify insertions, deletions and structural variants. Results Isolates were highly similar, with a distance of 13 variants between the most distant members of the cluster. The most sensitive analysis classified the 22 isolates into 18 groups. Four of the isolates did not appear to share a recent common ancestor with the largest clade; another four isolates had an uncertain ancestral relationship with the largest clade. Conclusion Whole genome sequencing, with analysis of single-nucleotide polymorphisms, insertions, deletions, structural variants and subpopulations, enabled the highest possible level of discrimination between cluster members, clarifying likely transmission pathways and exposing the complexity of strain origin. The analysis provides a basis for targeted public health intervention and enhanced classification of future isolates linked to the cluster. PMID:26938641

  3. A comparison of fertility control and lethal control of bovine tuberculosis in badgers: the impact of perturbation induced transmission.

    PubMed

    Swinton, J; Tuyttens, F; MacDonald, D; Nokes, D J; Cheeseman, C L; Clifton-Hadley, R

    1997-05-29

    In this paper we use mathematical modelling to consider the broad advantages and disadvantages of fertility control over lethal control for bovine tuberculosis in badger populations. We use a deliberately simple model, attempting to capture only the key transmission processes. The model is parametrized with reference to the long-term Woodchester Park study. Estimates of mortality rate from this study suggest no significant extra mortality risk for animals with evidence of infection as indicated by the presence of anti-Mycobacterium bovis antibodies or M. bovis isolation. We find that large reductions in prevalence are sometimes the consequence of only moderate reductions in population numbers. If we assume that the act of control does not in itself affect transmission rates, then as far as eradication is concerned, both fertility control and mortality control operate through the same epidemiological mechanism, the removal of susceptibles: if one is in principle capable of keeping a population low enough to be infection free then so is the other. It is necessary to continue either form of control at regular intervals to maintain a constant level of infection in the long term. If control were to be stopped, return to precontrol levels of badger population and infection prevalence would be expected within a few years. Fertility control is less effective in reducing population density than lethal control since it can only act, at maximum, to remove one age cohort per year. It is also less effective in reducing transmission as it can only ever remove susceptibles, while lethal control also removes infectious badgers. However, if the social disturbance caused by lethal control does in fact increase contact rates for the remaining infectious badgers, the relative efficacies of the two strategies become a great deal less clear. While we have no quantitative data on the extent to which social perturbation does act to promote transmission, model simulations show that it is

  4. Tuberculosis and mass gatherings-opportunities for defining burden, transmission risk, and the optimal surveillance, prevention, and control measures at the annual Hajj pilgrimage.

    PubMed

    Zumla, Alimuddin; Saeed, Abdulaziz Bin; Alotaibi, Badriah; Yezli, Saber; Dar, Osman; Bieh, Kingsley; Bates, Matthew; Tayeb, Tamara; Mwaba, Peter; Shafi, Shuja; McCloskey, Brian; Petersen, Eskild; Azhar, Esam I

    2016-06-01

    Tuberculosis (TB) is now the most common infectious cause of death worldwide. In 2014, an estimated 9.6 million people developed active TB. There were an estimated three million people with active TB including 360000 with multidrug-resistant TB (MDR-TB) who were not diagnosed, and such people continue to fuel TB transmission in the community. Accurate data on the actual burden of TB and the transmission risk associated with mass gatherings are scarce and unreliable due to the small numbers studied and methodological issues. Every year, an estimated 10 million pilgrims from 184 countries travel to the Kingdom of Saudi Arabia (KSA) to perform the Hajj and Umrah pilgrimages. A large majority of pilgrims come from high TB burden and MDR-TB endemic areas and thus many may have undiagnosed active TB, sub-clinical TB, and latent TB infection. The Hajj pilgrimage provides unique opportunities for the KSA and the 184 countries from which pilgrims originate, to conduct high quality priority research studies on TB under the remit of the Global Centre for Mass Gatherings Medicine. Research opportunities are discussed, including those related to the definition of the TB burden, transmission risk, and the optimal surveillance, prevention, and control measures at the annual Hajj pilgrimage. The associated data are required to develop international recommendations and guidelines for TB management and control at mass gathering events. PMID:26873277

  5. Cost estimation of HVDC transmission system of Bangka's NPP candidates

    NASA Astrophysics Data System (ADS)

    Liun, Edwaren; Suparman

    2014-09-01

    Regarding nuclear power plant development in Bangka Island, it can be estimated that produced power will be oversupply for the Bangka Island and needs to transmit to Sumatra or Java Island. The distance between the regions or islands causing considerable loss of power in transmission by alternating current, and a wide range of technical and economical issues. The objective of this paper addresses to economics analysis of direct current transmission system to overcome those technical problem. Direct current transmission has a stable characteristic, so that the power delivery from Bangka to Sumatra or Java in a large scale efficiently and reliably can be done. HVDC system costs depend on the power capacity applied to the system and length of the transmission line in addition to other variables that may be different.

  6. Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines

    PubMed Central

    Mphaphlele, Matsie; Dharmadhikari, Ashwin S.; Jensen, Paul A.; Rudnick, Stephen N.; van Reenen, Tobias H.; Pagano, Marcello A.; Leuschner, Wilhelm; Sears, Tim A.; Milonova, Sonya P.; van der Walt, Martie; Stoltz, Anton C.; Weyer, Karin

    2015-01-01

    Rationale: Transmission is driving the global tuberculosis epidemic, especially in congregate settings. Worldwide, natural ventilation is the most common means of air disinfection, but it is inherently unreliable and of limited use in cold climates. Upper room germicidal ultraviolet (UV) air disinfection with air mixing has been shown to be highly effective, but improved evidence-based dosing guidelines are needed. Objectives: To test the efficacy of upper room germicidal air disinfection with air mixing to reduce tuberculosis transmission under real hospital conditions, and to define the application parameters responsible as a basis for proposed new dosing guidelines. Methods: Over an exposure period of 7 months, 90 guinea pigs breathed only untreated exhaust ward air, and another 90 guinea pigs breathed only air from the same six-bed tuberculosis ward on alternate days when upper room germicidal air disinfection was turned on throughout the ward. Measurements and Main Results: The tuberculin skin test conversion rates (>6 mm) of the two chambers were compared. The hazard ratio for guinea pigs in the control chamber converting their skin test to positive was 4.9 (95% confidence interval, 2.8–8.6), with an efficacy of approximately 80%. Conclusions: Upper room germicidal UV air disinfection with air mixing was highly effective in reducing tuberculosis transmission under hospital conditions. These data support using either a total fixture output (rather than electrical or UV lamp wattage) of 15–20 mW/m3 total room volume, or an average whole-room UV irradiance (fluence rate) of 5–7 μW/cm2, calculated by a lighting computer-assisted design program modified for UV use. PMID:25928547

  7. Effect of Diagnostic and Treatment Delay on the Risk of Tuberculosis Transmission in Shenzhen, China: An Observational Cohort Study, 1993–2010

    PubMed Central

    Yang, Yingzhou; Chu, Ping; Liu, Xiaoli; Zhao, Meigui; Tan, Weiguo; Xu, Li; Wu, Qingfang; Guan, Hongyun; Liu, Jinhong; Liu, Haitao; Chen, Ray Y.; Jia, Zhongwei

    2013-01-01

    Introduction To understand better the risk of tuberculosis transmission with increasing delay in tuberculosis treatment, we undertook a retrospective cohort study in Shenzhen, China. Methods All pulmonary tuberculosis cases in the Shenzhen tuberculosis surveillance database from 1993–2010 were included. Sputum smear positivity and presence of pulmonary cavity were used as proxies for risk of tuberculosis transmission. Results Among 48,441pulmonary tuberculosis cases, 70% presented with symptoms of pulmonary TB, 62% were sputum smear positive, and 21% had a pulmonary cavity on chest x-ray. 95.3% of patients self-presented for evaluation of illness after a median 58 days of delay after symptoms began. The proportion presenting sputum smear positive (p<0.001) and with a pulmonary cavity (p<0.001) increased significantly with increasing duration of delay. Conclusions Delayed diagnosis and treatment of tuberculosis is associated with a significantly increased risk of pulmonary sputum smear positivity and pulmonary cavity. To decrease risk of transmission, treatment delay needs to be reduced further. PMID:23826313

  8. Cough Aerosol Cultures of Mycobacterium tuberculosis: Insights on TST / IGRA Discordance and Transmission Dynamics

    PubMed Central

    Jones-López, Edward C.; White, Laura F.; Kirenga, Bruce; Mumbowa, Francis; Ssebidandi, Martin; Moine, Stephanie; Mbabazi, Olive; Mboowa, Gerald; Ayakaka, Irene; Kim, Soyeon; Thornton, Christina S.; Okwera, Alphonse; Joloba, Moses; Fennelly, Kevin P.

    2015-01-01

    Rationale The diagnosis of latent tuberculosis (TB) infection (LTBI) is complicated by the absence of a gold standard. Discordance between tuberculin skin tests (TST) and interferon gamma release assays (IGRA) occurs in 10–20% of individuals, but the underlying mechanisms are poorly understood. Methods We analyzed data from a prospective household contact study that included cough aerosol culture results from index cases, environmental and contact factors. We assessed contacts for LTBI using TST and IGRA at baseline and six weeks. We examined TST/IGRA discordance in qualitative and quantitative analyses, and used multivariable logistic regression analysis with generalized estimating equations to analyze predictors of discordance. Measurements and Results We included 96 TB patients and 384 contacts. Discordance decreased from 15% at baseline to 8% by six weeks. In adjusted analyses, discordance was related to less crowding (p = 0.004), non-cavitary disease (OR 1.41, 95% CI: 1.02–1.96; p = 0.03), and marginally with BCG vaccination in contacts (OR 1.40, 95% CI: 0.99–1.98, p = 0.06). Conclusions We observed significant individual variability and temporal dynamism in TST and IGRA results in household contacts of pulmonary TB cases. Discordance was associated with a less intense infectious exposure, and marginally associated with a BCG-mediated delay in IGRA conversion. Cough aerosols provide an additional dimension to the assessment of infectiousness and risk of infection in contacts. PMID:26394149

  9. Comparison of models for piping transmission loss estimations

    NASA Astrophysics Data System (ADS)

    Catron, Fred W.; Mann, J. Adin

    2005-09-01

    A frequency dependent model for the transmission loss of piping is important for accurate estimates of the external radiation from pipes and the vibration level of the pipe walls. A statistical energy analysis model is used to predict the transmission loss of piping. Key terms in the model are the modal density and the radiation efficiency of the piping wall. Several available models for each are compared in reference to measured data. In low frequency octave bands, the modal density is low. The model of the transmission loss in these octave bands is augmented with a mass law model in the low frequency regime where the number of modes is small. The different models and a comparison of the models will be presented.

  10. ESTIMATING WITHIN-SCHOOL CONTACT NETWORKS TO UNDERSTAND INFLUENZA TRANSMISSION

    PubMed Central

    Potter, Gail E.; Handcock, Mark S.; Longini, Ira M.; Halloran, M. Elizabeth

    2012-01-01

    Many epidemic models approximate social contact behavior by assuming random mixing within mixing groups (e.g., homes, schools, and workplaces). The effect of more realistic social network structure on estimates of epidemic parameters is an open area of exploration. We develop a detailed statistical model to estimate the social contact network within a high school using friendship network data and a survey of contact behavior. Our contact network model includes classroom structure, longer durations of contacts to friends than non-friends and more frequent contacts with friends, based on reports in the contact survey. We performed simulation studies to explore which network structures are relevant to influenza transmission. These studies yield two key findings. First, we found that the friendship network structure important to the transmission process can be adequately represented by a dyad-independent exponential random graph model (ERGM). This means that individual-level sampled data is sufficient to characterize the entire friendship network. Second, we found that contact behavior was adequately represented by a static rather than dynamic contact network. We then compare a targeted antiviral prophylaxis intervention strategy and a grade closure intervention strategy under random mixing and network-based mixing. We find that random mixing overestimates the effect of targeted antiviral prophylaxis on the probability of an epidemic when the probability of transmission in 10 minutes of contact is less than 0.004 and underestimates it when this transmission probability is greater than 0.004. We found the same pattern for the final size of an epidemic, with a threshold transmission probability of 0.005. We also find random mixing overestimates the effect of a grade closure intervention on the probability of an epidemic and final size for all transmission probabilities. Our findings have implications for policy recommendations based on models assuming random mixing, and

  11. Computing estimates of material properties from transmission eigenvalues

    NASA Astrophysics Data System (ADS)

    Giorgi, Giovanni; Haddar, Houssem

    2012-05-01

    This work is motivated by inverse scattering problems, those problems where one is interested in reconstructing the shape and the material properties of an inclusion from electromagnetic farfield measurements. More precisely, we are interested in complementing the so-called sampling methods by providing an estimate of the material properties of the sought inclusion. We use for this purpose a measure of the first transmission eigenvalue. Our method is then based on computing the desired estimate by reformulating the so-called interior transmission eigenvalue problem as an eigenvalue problem for the material coefficients. We will restrict ourselves to the two-dimensional setting of the problem and treat the cases of both transverse electric and transverse magnetic polarizations. We present a number of numerical experiments that validate our methodology for homogeneous and inhomogeneous inclusions and backgrounds. We also treat the case of a background with absorption and the case of scatterers with multiple connected components of different refractive indices.

  12. Digital frequency estimation in burst mode QPSK transmission

    NASA Astrophysics Data System (ADS)

    Bellini, S.; Molinari, C.; Tartara, G.

    1990-07-01

    In burst digital transmission using PSK modulation with coherent detection, the recovery of the carrier reference phase and the symbol clock is a key aspect. If all users have a common clock synchronization, symbol timing needs not to be recovered in each burst. A digital processor for carrier recovery without preambles, in the presence of frequency offset, is considered. As an example, a 2 Mb/s QPSK transmission system is considered in which Eb/No = 10 dB, and the burst and estimation interval length L = 15. Using the algorithm described and averaging eight successive estimated frequency offsets, in order to eliminate anomalous errors, the bit-error-rate degradation is equal to 0.14 dB when Delta-f = 20 kHz.

  13. Parameter estimation based synchronization for an epidemic model with application to tuberculosis in Cameroon

    NASA Astrophysics Data System (ADS)

    Bowong, Samuel; Kurths, Jurgen

    2010-10-01

    We propose a method based on synchronization to identify the parameters and to estimate the underlying variables for an epidemic model from real data. We suggest an adaptive synchronization method based on observer approach with an effective guidance parameter to update rule design only from real data. In order, to validate the identifiability and estimation results, numerical simulations of a tuberculosis (TB) model using real data of the region of Center in Cameroon are performed to estimate the parameters and variables. This study shows that some tools of synchronization of nonlinear systems can help to deal with the parameter and state estimation problem in the field of epidemiology. We exploit the close link between mathematical modelling, structural identifiability analysis, synchronization, and parameter estimation to obtain biological insights into the system modelled.

  14. Compensatory Mutations of Rifampin Resistance Are Associated with Transmission of Multidrug-Resistant Mycobacterium tuberculosis Beijing Genotype Strains in China.

    PubMed

    Li, Qin-Jing; Jiao, Wei-Wei; Yin, Qing-Qin; Xu, Fang; Li, Jie-Qiong; Sun, Lin; Xiao, Jing; Li, Ying-Jia; Mokrousov, Igor; Huang, Hai-Rong; Shen, A-Dong

    2016-05-01

    Mycobacterium tuberculosis can acquire resistance to rifampin (RIF) through mutations in the rpoB gene. This is usually accompanied by a fitness cost, which, however, can be mitigated by secondary mutations in the rpoA or rpoC gene. This study aimed to identify rpoA and rpoC mutations in clinical M. tuberculosis isolates in northern China in order to clarify their role in the transmission of drug-resistant tuberculosis (TB). The study collection included 332 RIF-resistant and 178 RIF-susceptible isolates. The majority of isolates belonged to the Beijing genotype (95.3%, 486/510 isolates), and no mutation was found in rpoA or rpoC of the non-Beijing genotype strains. Among the Beijing genotype strains, 27.8% (89/320) of RIF-resistant isolates harbored nonsynonymous mutations in the rpoA (n = 6) or rpoC (n = 83) gene. The proportion of rpoC mutations was significantly higher in new cases (P = 0.023) and in strains with the rpoB S531L mutation (P < 0.001). In addition, multidrug-resistant (MDR) strains with rpoC mutations were significantly associated with 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat clustering (P = 0.016). In summary, we believe that these findings indirectly suggest an epistatic interaction of particular mutations related to RIF resistance and strain fitness and, consequently, the role of such mutations in the spread of MDR M. tuberculosis strains. PMID:26902762

  15. Evaluating Transmissivity Estimates from Well Hydrographs in Karst Aquifers

    SciTech Connect

    Powers, J.g.; Shevenell, l

    1999-07-01

    Hydrograph recessions from rainfall events have previously been analyzed for discharge at springs and streams; however, relatively little quantitative research has been conducted with regard to hydrograph analysis of recessions from monitoring wells screened in karst aquifers. In previous work a quantitative hydrography analysis technique has been proposed born which matrix transmissivity (i.e., transmissivity of intergranular porosity) and specific yields of matrix, fracture, and conduit components of the aquifer may be determined from well hydrography. The technique has yielded realistic results at three sites tested by the authors thus far (Y-12, Oak Ridge, TN; Crane, IN, and Ft. Campbell, KY). Observed field data, as well as theoretical considerations, show that karst well hydrography are valid indicators of hydraulic properties of the associated karst aquifers. Results show matrix transmissivity (T) values to be in good agreement with values calculated using more traditional parameter estimation techniques such as aquifer pumping tests and slug tests in matrix dominated wells. While the hydrograph analysis technique shows promise for obtaining reliable estimates of karst aquifer T with a simple, relatively inexpensive and passive method, the utility of the technique is limited in its application depending on site-specific hydrologic conditions, which include shallow, submerged conduit systems located in areas with sufficient rainfall for water levels to respond to precipitation events.

  16. Use of genotyping based clustering to quantify recent tuberculosis transmission in Guadeloupe during a seven years period: analysis of risk factors and access to health care

    PubMed Central

    2013-01-01

    Background The present study aimed to characterize Mycobacterium tuberculosis population structure and to identify transmission chains and risk factors by prospective molecular typing in conjunction with conventional epidemiological investigations in the French overseas department of Guadeloupe. Methods The study included all the culture-positive TB cases (1 clinical isolate per patient; n = 129) diagnosed between a seven year period (April 4th, 1999 to December 31st, 2005). Prospective molecular typing was performed using spoligotyping and VNTRs, and a subset of 44 M. tuberculosis isolates found to be clustered was retrospectively typed using 12-loci MIRUs. Data were compared using the SITVIT2 database, followed by analysis of risk factors in function of clustering of the isolates and available demographic and socioeconomic data. Results The study sample was characterized by a majority of new cases (87.4%); a moderate proportion of drug-resistance (7.8%); a high level of immigration (51.2% foreign-born) originating from high TB/HIV incidence neighboring islands such as Haiti or Dominican Republic; lower socioeconomic conditions (70.7% of jobless, average income 824 EUR/month); and a significantly higher proportion of TB/HIV co-infected cases (38.2% vs. 8.5%; p < 0.001), and extrapulmonary disease (18.2% vs. 4.8%; p < 0.02) among migrants as compared to French patients. The study revealed an important delay in access to healthcare with a median delay of 74.5 days between the 1st symptoms and clinical suspicion of TB. Prospective molecular typing based on spoligotyping and 5-loci VNTRs showed that evolutionary recent Euro-American lineages predominated in Guadeloupe (91.5% of isolates). In conjunction with epidemiological data, it allowed to estimate a recent transmission rate of 18.6%, which was close to the rate of 16.7% estimated using retrospective 12-loci MIRU typing. Although a higher proportion of cases in older age-group were apparently linked

  17. Layered material characterization using ultrasonic transmission. An inverse estimation methodology.

    PubMed

    Messineo, María G; Rus, Guillermo; Eliçabe, Guillermo E; Frontini, Gloria L

    2016-02-01

    This paper presents an inverse methodology with the aim to characterize a layered material through the identification of acoustical and mechanical properties of its layers. The framework to accomplish this objective is provided by the Inverse Problems (IPs) theory. Material characterization refers to the detection and localization of discontinuities, as well as to the identification of physical properties, in order to predict the material behaviour. In this particular case, the IP is solved in the form of a parameter estimation problem, in which the goal is the estimation of the characteristic acoustic impedance, transit time, and attenuation of each layer. These parameters are directly related to relevant material properties, such as the speed of sound, density, elastic modulus and elastic energy dissipation constants. The IP solution is obtained by minimizing a cost functional formulated as the least squares error between the waveform calculated using an equivalent model, and the measured waveform obtained from ultrasonic transmission tests. The applied methodology allowed the accurate estimation of the desired parameters in materials composed of up to three layers. As a second contribution, a power law frequency dependence of the wave attenuation was identified for several homogeneous materials, based on the same ultrasonic transmission experiments. PMID:26456278

  18. Monitoring of Transmission of Tuberculosis between Wild Boars and Cattle: Genotypical Analysis of Strains by Molecular Epidemiology Techniques

    PubMed Central

    Serraino, Andrea; Marchetti, Giulia; Sanguinetti, Valeria; Rossi, Maria Cristina; Zanoni, Renato Giulio; Catozzi, Lidia; Bandera, Alessandra; Dini, Walter; Mignone, Walter; Franzetti, Fabio; Gori, Andrea

    1999-01-01

    An epidemiological survey for the monitoring of bovine tuberculosis transmission was carried out in western Liguria, a region in northern Italy. Fifteen Mycobacterium bovis strains were isolated from 63 wild boar samples (62 from mandibular lymph nodes and 1 from a liver specimen). Sixteen mediastinal lymph nodes of 16 head of cattle were collected, and 15 Mycobacterium bovis strains were subsequently cultured. All M. bovis strains isolated from cattle and wild boars were genotyped by spoligotyping and by restriction fragment length polymorphism (RFLP) analysis with the IS6110 and IS1081 probes. All M. bovis strains showed the typical spoligotype characterized by the absence of the 39 to 43 spacers in comparison with the number in M. tuberculosis. A total of nine different clusters were identified by spoligotyping. The largest cluster included 9 strains isolated from wild boars and 11 strains isolated from cattle, thus confirming the possibility of transmission between the two animal species. Fingerprinting by RFLP analysis with the IS6110 probe showed an identical single-band pattern for 29 of 30 strains analyzed, and only 1 strain presented a five-band pattern. The use of IS1081 as a second probe was useful for differentiation of M. bovis from M. bovis BCG but not for differentiation among M. bovis strains, which presented the same undifferentiated genomic profile. In relation to the epidemiological investigation, we hypothesized that the feeding in pastures contaminated by cattle discharges could represent the most probable route of transmission of M. bovis between the two animal species. In conclusion, our results confirmed the higher discriminatory power of spoligotyping in relation to that of RFLP analysis for the differentiation of M. bovis genomic profiles. Our data showed the presence of a common M. bovis genotype in both cattle and wild boars, confirming the possible interspecies transmission of M. bovis. PMID:10449449

  19. Evaluation of spoligotyping in a study of the transmission of Mycobacterium tuberculosis.

    PubMed Central

    Goguet de la Salmonière, Y O; Li, H M; Torrea, G; Bunschoten, A; van Embden, J; Gicquel, B

    1997-01-01

    Spoligotyping (for spacer oligotyping) is an easy, economical, and rapid way of typing Mycobacterium tuberculosis complex strains with the DR spacer markers (J. Kamerbeek et al., J. Clin. Microbiol. 35:907-914, 1997; D. van Soolingen et al., 33:3234-3248, 1995). The stability of the markers was demonstrated by showing that all the Mycobacterium bovis BCG strains tested gave the same spoligotyping pattern. None of the 42 atypical mycobacterial strains tested gave a spoligotyping signal, indicating the specificity of the technique for M. tuberculosis complex. The utility of the spoligotyping method was demonstrated by analyzing 106 isolates of M. tuberculosis obtained over 1 year in three Paris hospitals. The results obtained by this technique were compared to those obtained by Torrea et al. (G. Torrea et al., J. Clin. Microbiol. 34:1043-1049, 1996) by IS6110-based restriction fragment length polymorphism (RFLP) analysis. Strains from patients with epidemiological relationships that were in the same IS6110-RFLP cluster were also in the same spoligotyping group. Spoligotyping was more discriminative than RFLP analysis for strains with one or two copies of IS6110. RFLP analysis did not discriminate between the nine strains with one or two IS6110 bands with no known epidemiological relation, whereas spoligotyping distinguished between eight different types. IS6I10-RFLP analysis split some of the spoligotyping clusters, particularly when the IS6110 copy number was high. Therefore, we propose a strategy for typing M. tuberculosis strains in which both markers are used. PMID:9276389

  20. Estimating epidemiological parameters for bovine tuberculosis in British cattle using a Bayesian partial-likelihood approach

    PubMed Central

    O'Hare, A.; Orton, R. J.; Bessell, P. R.; Kao, R. R.

    2014-01-01

    Fitting models with Bayesian likelihood-based parameter inference is becoming increasingly important in infectious disease epidemiology. Detailed datasets present the opportunity to identify subsets of these data that capture important characteristics of the underlying epidemiology. One such dataset describes the epidemic of bovine tuberculosis (bTB) in British cattle, which is also an important exemplar of a disease with a wildlife reservoir (the Eurasian badger). Here, we evaluate a set of nested dynamic models of bTB transmission, including individual- and herd-level transmission heterogeneity and assuming minimal prior knowledge of the transmission and diagnostic test parameters. We performed a likelihood-based bootstrapping operation on the model to infer parameters based only on the recorded numbers of cattle testing positive for bTB at the start of each herd outbreak considering high- and low-risk areas separately. Models without herd heterogeneity are preferred in both areas though there is some evidence for super-spreading cattle. Similar to previous studies, we found low test sensitivities and high within-herd basic reproduction numbers (R0), suggesting that there may be many unobserved infections in cattle, even though the current testing regime is sufficient to control within-herd epidemics in most cases. Compared with other, more data-heavy approaches, the summary data used in our approach are easily collected, making our approach attractive for other systems. PMID:24718762

  1. Estimating epidemiological parameters for bovine tuberculosis in British cattle using a Bayesian partial-likelihood approach.

    PubMed

    O'Hare, A; Orton, R J; Bessell, P R; Kao, R R

    2014-05-22

    Fitting models with Bayesian likelihood-based parameter inference is becoming increasingly important in infectious disease epidemiology. Detailed datasets present the opportunity to identify subsets of these data that capture important characteristics of the underlying epidemiology. One such dataset describes the epidemic of bovine tuberculosis (bTB) in British cattle, which is also an important exemplar of a disease with a wildlife reservoir (the Eurasian badger). Here, we evaluate a set of nested dynamic models of bTB transmission, including individual- and herd-level transmission heterogeneity and assuming minimal prior knowledge of the transmission and diagnostic test parameters. We performed a likelihood-based bootstrapping operation on the model to infer parameters based only on the recorded numbers of cattle testing positive for bTB at the start of each herd outbreak considering high- and low-risk areas separately. Models without herd heterogeneity are preferred in both areas though there is some evidence for super-spreading cattle. Similar to previous studies, we found low test sensitivities and high within-herd basic reproduction numbers (R0), suggesting that there may be many unobserved infections in cattle, even though the current testing regime is sufficient to control within-herd epidemics in most cases. Compared with other, more data-heavy approaches, the summary data used in our approach are easily collected, making our approach attractive for other systems. PMID:24718762

  2. Global and Regional Burden of Isoniazid-Resistant Tuberculosis

    PubMed Central

    Yuen, Courtney M.; Jenkins, Helen E.; Rodriguez, Carly A.; Keshavjee, Salmaan

    2015-01-01

    BACKGROUND: Isoniazid has been the backbone of tuberculosis chemotherapy for 6 decades. Resistance to isoniazid threatens the efficacy of treatment of tuberculosis disease and infection. To inform policies around treatment of tuberculosis disease and infection in children, we sought to estimate both the proportion of child tuberculosis cases with isoniazid resistance and the number of incident isoniazid-resistant tuberculosis cases in children, by region. METHODS: We determined the relationship between rates of isoniazid resistance among child cases and among treatment-naive adult cases through a systematic literature review. We applied this relationship to regional isoniazid resistance estimates to estimate proportions of childhood tuberculosis cases with isoniazid resistance. We applied these proportions to childhood tuberculosis incidence estimates to estimate numbers of children with isoniazid-resistant tuberculosis. RESULTS: We estimated 12.1% (95% confidence interval [CI] 9.8% to 14.8%) of all children with tuberculosis had isoniazid-resistant disease, representing 120 872 (95% CI 96 628 to 149 059) incident cases of isoniazid-resistant tuberculosis in children in 2010. The majority of these occurred in the Western Pacific and Southeast Asia regions; the European region had the highest proportion of child tuberculosis cases with isoniazid resistance, 26.1% (95% CI: 20.0% to 33.6%). CONCLUSIONS: The burden of isoniazid-resistant tuberculosis in children is substantial, and risk varies considerably by setting. The large number of child cases signals extensive ongoing transmission from adults with isoniazid-resistant tuberculosis. The risk of isoniazid resistance must be considered when evaluating treatment options for children with disease or latent infection to avoid inadequate treatment and consequent poor outcomes. PMID:26034243

  3. LOSS ESTIMATE FOR ITER ECH TRANSMISSION LINE INCLUDING MULTIMODE PROPAGATION

    SciTech Connect

    Shapiro, Michael; Bigelow, Tim S; Caughman, John B; Rasmussen, David A

    2010-01-01

    The ITER electron cyclotron heating (ECH) transmission lines (TLs) are 63.5-mm-diam corrugated waveguides that will each carry 1 MW of power at 170 GHz. The TL is defined here as the corrugated wave guide system connecting the gyrotron mirror optics unit (MO U) to the entrance of the ECH launcher and includes miter bends and other corrugated wave guide components. The losses on the ITER TL have been calculated for four possible cases corresponding to having HE(11) mode purity at the input of the TL of 100, 97, 90, and 80%. The losses due to coupling, ohmic, and mode conversion loss are evaluated in detail using a numerical code and analytical approaches. Estimates of the calorimetric loss on the line show that the output power is reduced by about 5, +/- 1% because of ohmic loss in each of the four cases. Estimates of the mode conversion loss show that the fraction of output power in the HE(11) mode is similar to 3% smaller than the fraction of input power in the HE(11) mode. High output mode purity therefore can be achieved only with significantly higher input mode purity. Combining both ohmic and mode conversion loss, the efficiency of the TL from the gyrotron MOU to the ECH launcher can be roughly estimated in theory as 92% times the fraction of input power in the HE(11) mode.

  4. Tuberculosis transmission between foreign- and native-born populations in the EU/EEA: a systematic review

    PubMed Central

    Sandgren, Andreas; Sañé Schepisi, Monica; Sotgiu, Giovanni; Huitric, Emma; Migliori, Giovanni Battista; Manissero, Davide; van der Werf, Marieke J.; Girardi, Enrico

    2014-01-01

    Tuberculosis (TB) control programmes of many low TB incidence countries of the European Union/European Economic Area (EU/EEA) perceive challenges in controlling TB due to high numbers of TB in migrants from high-incidence countries. To assess the extent of TB transmission from the foreign-born to the native-born population, we quantitatively investigated the dynamics of TB transmission between these populations in the EU/EEA, using published molecular epidemiological studies. We searched PubMed and EMBASE databases from 1990 to August 2012. We identified 15 studies performed during 1992–2007 covering 12,366 cases, of which median (range) 49.2% (17.7%–86.4%) were foreign-born. The proportion of clustered isolates ranged between 8.5% and 49.1% of the total number of TB cases genotyped and among these, foreign-born cases were equally or more likely to have unique isolates compared to native-born cases. One third of the clusters were “mixed”, i.e. composed of foreign- and native-born cases, involving 0–34.2% of all genotyped cases. Cross-transmission among foreign and native populations was bidirectional, with wide differences across studies. This systematic review provides evidence that TB in a foreign-born population does not have a significant influence on TB in the native population in EU/EEA. PMID:24114966

  5. Mathematical model of tuberculosis transmission in a two-strain with vaccination

    NASA Astrophysics Data System (ADS)

    Nainggolan, J.; Supian, S.; Supriatna, A. K.; Anggriani, N.

    2014-02-01

    This paper deals with the mathematical analysis of the spread of tuberculosis with vaccination in a two-strain model. The vaccination reproduction ratio (Rrs) and equilibria quantities for the models are determined and stability of the solution is analyzed. We prove that if the vaccination reproduction ratio Rrs < 1 the disease free equilibrium is locally and asymptotically stable on the nonnegative orthant and if Rrs > 1 of the other equilibria is locally and asymptotically stable. At the end of this study, the numerical computation presented and it shows that vaccination and treatment capable to reduce the number of exposed and infected compartments.

  6. Global analysis of a dynamical model for transmission of tuberculosis with a general contact rate

    NASA Astrophysics Data System (ADS)

    Bowong, Samuel; Tewa, Jean Jules

    2010-11-01

    This paper deals with the global analysis of a dynamical model for the spread of tuberculosis with a general contact rate. The model exhibits the traditional threshold behavior. We prove that when the basic reproduction ratio is less than unity, then the disease-free equilibrium is globally asymptotically stable and when the basic reproduction ratio is great than unity, a unique endemic equilibrium exists and is globally asymptotically stable under certain conditions. The stability of equilibria is derived through the use of Lyapunov stability theory and LaSalle's invariant set theorem. Numerical simulations are provided to illustrate the theoretical results.

  7. Challenges in Obtaining Estimates of the Risk of Tuberculosis Infection During Overseas Deployment.

    PubMed

    Mancuso, James D; Geurts, Mia

    2015-12-01

    Estimates of the risk of tuberculosis (TB) infection resulting from overseas deployment among U.S. military service members have varied widely, and have been plagued by methodological problems. The purpose of this study was to estimate the incidence of TB infection in the U.S. military resulting from deployment. Three populations were examined: 1) a unit of 2,228 soldiers redeploying from Iraq in 2008, 2) a cohort of 1,978 soldiers followed up over 5 years after basic training at Fort Jackson in 2009, and 3) 6,062 participants in the 2011-2012 National Health and Nutrition Examination Survey (NHANES). The risk of TB infection in the deployed population was low-0.6% (95% confidence interval [CI]: 0.1-2.3%)-and was similar to the non-deployed population. The prevalence of latent TB infection (LTBI) in the U.S. population was not significantly different among deployed and non-deployed veterans and those with no military service. The limitations of these retrospective studies highlight the challenge in obtaining valid estimates of risk using retrospective data and the need for a more definitive study. Similar to civilian long-term travelers, risks for TB infection during deployment are focal in nature, and testing should be targeted to only those at increased risk. PMID:26416114

  8. [Commemorative lecture of receiving Imamura Memorial Prize. III. Estimating the year of eradication of tuberculosis in Japan].

    PubMed

    Ohmori, M

    1994-09-01

    The year by which tuberculosis could be eradicated, has been discussed for several foreign countries, and based on those results, new strategic plans and goals have been elaborated. Therefore, in Japan too, it was desired to estimate the point at which eradication of tuberculosis would be achieved. The author estimated the year of eradication of tuberculosis, according to the criterion proposed by Dr. Styblo that "tuberculosis is eradicated when the prevalence of tuberculosis infection in the general population has fallen below 1% and continues to decrease". If the risk of infection is changing at a regular rate, it is possible to estimate the risk of infection at any particular time. Once the risk of infection is determined, it is also possible to calculate the age-specific prevalence of infection and the proportion of the population infected with tubercle bacilli at any given time. In Japan, the risk of infection before World War II was assumed to be around 4%; since then, it has declined on average, by 10 to 11% annually. The incidence rate in Japan also has declined, on average, by 10 to 11% annually. However, since late 1970s, the annual speed of decline of the incidence rate has slowed down. Therefore, I assumed that the recent trend of the infection risk is the same as the trend of the recent incidence rate among the 0-29 year age-group. The size of the effect of age on the risk of infection has been discussed. The author also considered age-effects in the model.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7967319

  9. Maintenance, spillover and spillback transmission of bovine tuberculosis in multi-host wildlife complexes: a New Zealand case study.

    PubMed

    Nugent, Graham

    2011-07-01

    The causative agent of bovine tuberculosis (bTB; Mycobacterium bovis) has a broad host range. The role of each animal species in spreading the disease depends on how transmission occurs, on the abundance of each host, and on the interactions between hosts. This paper explores differences in the roles individual host species can play in allowing M. bovis infection to persist and spread within a multi-species complex, using New Zealand as a case study. In New Zealand, four wild mammal species are frequently infected. Of these the brushtail possum is now regarded as the only true "maintenance" host. Red deer and ferrets can become maintenance hosts where their densities are exceptionally high, but more often they are "spillover" hosts, with most infection arising from moderately frequent inter-species transmission from possums. The latter situation is even more strongly the case for feral pigs. Spillover hosts may occasionally play a crucial epidemiological role by transmitting infection back to a potential maintenance host (spillback). Three key factors make spillback transmission far more epidemiologically important than its low frequency of occurrence might suggest--amplification of the reservoir of bTB, far greater spatial spread than by the maintenance host, and greater persistence of bTB in long-lived spillover hosts extending the risk of spillback far into the future. The risk of spillback is undoubtedly low, but it nonetheless determines the nature, scale and duration of management required. Eradication of the disease may require management of both the infection in maintenance hosts and reduction or elimination of any risk of spillback. PMID:21458931

  10. Estimation of the individual slaughterhouse surveillance sensitivity for bovine tuberculosis in Catalonia (North-Eastern Spain).

    PubMed

    Garcia-Saenz, A; Napp, S; Lopez, S; Casal, J; Allepuz, A

    2015-10-01

    The achievement of the Officially Tuberculosis Free (OTF) status in regions with low bovine Tuberculosis (bTB) herd prevalence, as is the case of North-Eastern Spain (Catalonia), might be a likely option in the medium term. In this context, risk-based approaches could be an alternative surveillance strategy to the costly current strategy. However, before any change in the system may be contemplated, a reliable estimate of the sensitivity of the different surveillance components is needed. In this study, we focused on the slaughterhouse component. The probability of detection of a bTB-infected cattle by the slaughterhouses in Catalonia was estimated as the product of three consecutive probabilities: (P1) the probability that a bTB-infected animal arrived at the slaughterhouse presenting Macroscopically Detectable Lesions (MDL); (P2) the probability that MDL were detected by the routine meat inspection process and (P3) the probability that the veterinary officer suspected bTB and sent the sample for laboratory confirmation. The first probability was obtained from data collected through the bTB eradication program carried out in Catalonia between 2005 and 2008, while the last two were obtained through the expert opinion of the veterinary officers working at the slaughterhouses who fulfilled a questionnaire administered during 2014. The bTB surveillance sensitivity of the different cattle slaughterhouses in Catalonia obtained in this study was 31.4% (CI 95%: 28.6-36.2), and there were important differences among them. The low bTB surveillance sensitivity was mainly related with the low probability that a bTB-infected animal arrived at the slaughterhouse presenting MDL (around 44.8%). The variability of the sensitivity among the different slaughterhouses could be explained by significant associations between some variables included in the survey and P2. For instance, factors like attendance to training courses, number of meat technicians and speed of the slaughter chain

  11. Estimating malaria transmission from humans to mosquitoes in a noisy landscape.

    PubMed

    Reiner, Robert C; Guerra, Carlos; Donnelly, Martin J; Bousema, Teun; Drakeley, Chris; Smith, David L

    2015-10-01

    A basic quantitative understanding of malaria transmission requires measuring the probability a mosquito becomes infected after feeding on a human. Parasite prevalence in mosquitoes is highly age-dependent, and the unknown age-structure of fluctuating mosquito populations impedes estimation. Here, we simulate mosquito infection dynamics, where mosquito recruitment is modelled seasonally with fractional Brownian noise, and we develop methods for estimating mosquito infection rates. We find that noise introduces bias, but the magnitude of the bias depends on the 'colour' of the noise. Some of these problems can be overcome by increasing the sampling frequency, but estimates of transmission rates (and estimated reductions in transmission) are most accurate and precise if they combine parity, oocyst rates and sporozoite rates. These studies provide a basis for evaluating the adequacy of various entomological sampling procedures for measuring malaria parasite transmission from humans to mosquitoes and for evaluating the direct transmission-blocking effects of a vaccine. PMID:26400195

  12. Estimating malaria transmission from humans to mosquitoes in a noisy landscape

    PubMed Central

    Reiner, Robert C.; Guerra, Carlos; Donnelly, Martin J.; Bousema, Teun; Drakeley, Chris; Smith, David L.

    2015-01-01

    A basic quantitative understanding of malaria transmission requires measuring the probability a mosquito becomes infected after feeding on a human. Parasite prevalence in mosquitoes is highly age-dependent, and the unknown age-structure of fluctuating mosquito populations impedes estimation. Here, we simulate mosquito infection dynamics, where mosquito recruitment is modelled seasonally with fractional Brownian noise, and we develop methods for estimating mosquito infection rates. We find that noise introduces bias, but the magnitude of the bias depends on the ‘colour' of the noise. Some of these problems can be overcome by increasing the sampling frequency, but estimates of transmission rates (and estimated reductions in transmission) are most accurate and precise if they combine parity, oocyst rates and sporozoite rates. These studies provide a basis for evaluating the adequacy of various entomological sampling procedures for measuring malaria parasite transmission from humans to mosquitoes and for evaluating the direct transmission-blocking effects of a vaccine. PMID:26400195

  13. Fast and low-cost decentralized surveillance of transmission of tuberculosis based on strain-specific PCRs tailored from whole genome sequencing data: a pilot study.

    PubMed

    Pérez-Lago, L; Martínez Lirola, M; Herranz, M; Comas, I; Bouza, E; García-de-Viedma, D

    2015-03-01

    Molecular epidemiology has transformed our knowledge of how tuberculosis (TB) is transmitted. Whole genome sequencing (WGS) has reached unprecedented levels of accuracy. However, it has increased technical requirements and costs, and analysis of data delays results. Our objective was to find a way to reconcile speed and ease of implementation with the high resolution of WGS. The targeted regional allele-specific oligonucleotide PCR (TRAP) assay presented here is based on allele-specific PCR targeting strain-specific single nucleotide polymorphisms, identified from WGS, and makes it possible to track actively transmitted Mycobacterium tuberculosis strains. A TRAP assay was optimized to track the most actively transmitted strains in a population in Almería, Southeast Spain, with high rates of TB. TRAP was transferred to the local laboratory where transmission was occurring. It performed well from cultured isolates and directly from sputa, enabling new secondary cases of infection from the actively transmitted strains to be detected. TRAP constitutes a fast, simple and low-cost tool that could modify surveillance of TB transmission. This pilot study could help to define a new model to survey TB transmission based on a decentralized multinodal network of local laboratories applying fast and low-cost TRAPs, which are developed by central reference centres, tailored to the specific demands of transmission at each local node. PMID:25614157

  14. Systematic review on tuberculosis transmission on aircraft and update of the European Centre for Disease Prevention and Control risk assessment guidelines for tuberculosis transmitted on aircraft (RAGIDA-TB).

    PubMed

    Kotila, Saara M; Payne Hallström, Lara; Jansen, Niesje; Helbling, Peter; Abubakar, Ibrahim

    2016-01-01

    As a setting for potential tuberculosis (TB) transmission and contact tracing, aircraft pose specific challenges. Evidence-based guidelines are needed to support the related-risk assessment and contact-tracing efforts. In this study evidence of TB transmission on aircraft was identified to update the Risk Assessment Guidelines for TB Transmitted on Aircraft (RAGIDA-TB) of the European Centre for Disease Prevention and Control (ECDC). Electronic searches were undertaken from Medline (Pubmed), Embase and Cochrane Library until 19 July 2013. Eligible records were identified by a two-stage screening process and data on flight and index case characteristics as well as contact tracing strategies extracted. The systematic literature review retrieved 21 records. Ten of these records were available only after the previous version of the RAGIDA guidelines (2009) and World Health Organization guidelines on TB and air travel (2008) were published. Seven of the 21 records presented some evidence of possible in-flight transmission, but only one record provided substantial evidence of TB transmission on an aircraft. The data indicate that overall risk of TB transmission on aircraft is very low. The updated ECDC guidelines for TB transmission on aircraft have global implications due to inevitable need for international collaboration in contract tracing and risk assessment. PMID:26848520

  15. Tuberculosis Transmission from Healthcare Workers to Patients and Co-workers: A Systematic Literature Review and Meta-Analysis

    PubMed Central

    Schepisi, Monica Sañé; Sotgiu, Giovanni; Contini, Silvia; Puro, Vincenzo; Ippolito, Giuseppe; Girardi, Enrico

    2015-01-01

    Healthcare workers (HCWs) are at risk of becoming infected with tuberculosis (TB), and potentially of being infectious themselves when they are ill. To assess the magnitude of healthcare-associated TB (HCA-TB) transmission from HCWs to patients and colleagues, we searched three electronic databases up to February 2014 to select primary studies on HCA-TB incidents in which a HCW was the index case and possibly exposed patients and co-workers were screened.We identified 34 studies out of 2,714 citations. In 29 individual investigations, active TB was diagnosed in 3/6,080 (0.05%) infants, 18/3,167 (0.57%) children, 1/3,600 (0.03%) adult patients and 0/2,407 HCWs. The quantitative analysis of 28 individual reports showed that combined proportions of active TB among exposed individuals were: 0.11% (95% CI 0.04–0.21) for infants, 0.38% (95% CI 0.01–1.60) for children, 0.09% (95% CI 0.02–0.22) for adults and 0.00% (95% CI 0.00–0.38) for HCWs. Combined proportions of individuals who acquired TB infection were: 0.57% (95% CI 7.28E-03 – 2.02) for infants, 0.9% (95% CI 0.40–1.60) for children, 4.32% (95% CI 1.43–8.67) for adults and 2.62% (95% CI 1.05–4.88) for HCWs. The risk of TB transmission from HCWs appears to be lower than that recorded in other settings or in the healthcare setting when the index case is not a HCW. To provide a firm evidence base for the screening strategies, more and better information is needed on the infectivity of the source cases, the actual exposure level of screened contacts, and the environmental characteristics of the healthcare setting. PMID:25835507

  16. Estimating the coverage of a targeted mobile tuberculosis screening programme among illicit drug users and homeless persons with truncated models

    PubMed Central

    VAN HEST, N. A. H.; De VRIES, G.; SMIT, F.; GRANT, A. D.; RICHARDUS, J. H.

    2008-01-01

    SUMMARY Truncated models are indirect methods to estimate the size of a hidden population which, in contrast to the capture–recapture method, can be used on a single information source. We estimated the coverage of a tuberculosis screening programme among illicit drug users and homeless persons with a mobile digital X-ray unit between 1 January 2003 and 31 December 2005 in Rotterdam, The Netherlands, using truncated models. The screening programme reached about two-third of the estimated target population at least once annually. The intended coverage (at least two chest X-rays per person per year) was about 23%. We conclude that simple truncated models can be used relatively easily on available single-source routine data to estimate the size of a population of illicit drug users and homeless persons. We assumed that the most likely overall bias in this study would be overestimation and therefore the coverage of the targeted mobile tuberculosis screening programme would be higher. PMID:17631692

  17. Estimation of hepatitis C virus infections resulting from vertical transmission in Egypt

    PubMed Central

    Benova, Lenka; Awad, Susanne F; Miller, F DeWolfe; Abu-Raddad, Laith J

    2015-01-01

    Despite having the highest hepatitis C virus (HCV) prevalence in the world, the ongoing level of HCV incidence in Egypt and its drivers are poorly understood. Whereas HCV mother-to-child infection is a well-established transmission route, there are no estimates of HCV infections resulting from vertical transmission for any country, including Egypt. The aim of this study was to estimate the absolute number of new HCV infections resulting from vertical transmission in Egypt. We developed a conceptual framework of HCV vertical transmission, expressed in terms of a mathematical model and based on maternal HCV antibody and viremia. The mathematical model estimated the number of HCV vertical infections nationally and for six subnational areas. Applying two vertical transmission risk estimates to the 2008 Egyptian birth cohort, we estimated that between 3,080 and 5,167 HCV infections resulted from vertical transmission among children born in 2008. HCV vertical transmission may account for half of incident cases in the <5-year age group. Disproportionately higher proportions of vertical infections were estimated in Lower Rural and Upper Rural subnational areas. This geographical clustering was a result of higher-area-level HCV prevalence among women and higher fertility rates. Conclusion: Vertical transmission is one of the primary HCV infection routes among children <5 years in Egypt. The absolute number of vertical transmissions and the young age at infection highlight a public health concern. These findings also emphasize the need to quantify the relative contributions of other transmission routes to HCV incidence in Egypt. (Hepatology 2015;61:834–842) PMID:25366418

  18. A contact investigation of the transmission of Mycobacterium tuberculosis from a nurse working in a newborn nursery and maternity ward.

    PubMed

    Ohno, Hitoshi; Ikegami, Yumiko; Kishida, Kenji; Yamamoto, Yoshiaki; Ikeda, Nobuaki; Taniguchi, Takashi; Ikeda, Takeshi; Sato, Atsuo; Kurasawa, Takuya; Miyanomae, Ken

    2008-02-01

    A nurse working in a newborn nursery and maternity ward developed 3+ smear-positive lung tuberculosis. The hospital infection control committee, in collaboration with the local public health and welfare center, conducted a contact investigation. The infection period was defined as April to August 2006. The investigation included 109 infant and mother pairs, 28 children aged under 10 years and their guardians, 62 coworkers, and 63 household visitors to the ward. Tuberculosis infection in infants and children aged under 5 years was primarily determined by tuberculin skin test (TST), while subjects aged 5 years or more were tested using QuantiFERON-TB Gold (QFT). The first investigation, in August 2006, was conducted in all subjects, and the second investigation, in October 2006, targeted selected subjects. No infants were TST-positive. Two children aged 1 year or under, vaccinated with bacillus Calmette-Guérin, were positive for TST, as determined by the criteria of the Japan Anti-Tuberculosis Association; however, other tests for tuberculosis were negative. Of the 13 QFT-positive adult subjects, 1 mother and 2 coworkers could have become infected with Mycobacterium tuberculosis through exposure to the index nurse. Fifty-four infants and 6 children underwent "window-period" prophylaxis, and 4 adults completed 6-month prophylactic treatment with isoniazid. To date, no secondary cases of tuberculosis disease have occurred. PMID:18297454

  19. Added value of molecular assay Xpert MTB/RIF compared to sputum smear microscopy to assess the risk of tuberculosis transmission in a low-prevalence country.

    PubMed

    Opota, O; Senn, L; Prod'hom, G; Mazza-Stalder, J; Tissot, F; Greub, G; Jaton, K

    2016-07-01

    Airborne precautions are required at hospital admission for patients with suspected pulmonary tuberculosis. The isolation is maintained until 3 serially collected sputum smears are acid-fast bacilli negative, a time- and labor-intensive method with limited sensitivity and specificity, which has a great impact on patient flow management. We evaluated the possibility of replacing the result of microscopy by the semiquantitative result of the molecular point-of-care test Xpert MTB/RIF to assess patients' transmission risk to quickly guide airborne isolation decisions in low-endemic countries. The performance of the Xpert MTB/RIF, used as a first-line test, was compared to the results of microscopy for specimens (n=242) collected from May 2010 to December 2014 in Lausanne, Switzerland. The sensitivity and specificity of Xpert MTB/RIF were 91.5% (65/71) and 99.6% (170/171), respectively, vs. 64.8% (46/71) and 94.2% (161/171) for microscopy. Samples with negative Xpert MTB/RIF were all smear negative for Mycobacterium tuberculosis (negative predictive value, 100%). The semiquantitative results of Xpert MTB/RIF-high, medium, low or very low-were found to correlate with acid-fast bacilli detection: positive predictive value of 100% (6/6), 96.5% (27/28), 52.2% (12/23) and 11.1% (1/9) respectively. Finally, when including clinical criteria, we identified 11 smear-negative but Xpert MTB/RIF-positive patients with a significant transmission potential. In conclusion, our data support the introduction of an Xpert MTB/RIF-based strategy as a replacement of smear microscopy for a faster and more accurate management of tuberculosis patients' transmission risk in a low-prevalence country. PMID:27139592

  20. Estimating Dengue Transmission Intensity from Case-Notification Data from Multiple Countries

    PubMed Central

    Imai, Natsuko; Dorigatti, Ilaria; Cauchemez, Simon; Ferguson, Neil M.

    2016-01-01

    Background Despite being the most widely distributed mosquito-borne viral infection, estimates of dengue transmission intensity and associated burden remain ambiguous. With advances in the development of novel control measures, obtaining robust estimates of average dengue transmission intensity is key for assessing the burden of disease and the likely impact of interventions. Methodology/Principle Findings We estimated the force of infection (λ) and corresponding basic reproduction numbers (R0) by fitting catalytic models to age-stratified incidence data identified from the literature. We compared estimates derived from incidence and seroprevalence data and assessed the level of under-reporting of dengue disease. In addition, we estimated the relative contribution of primary to quaternary infections to the observed burden of dengue disease incidence. The majority of R0 estimates ranged from one to five and the force of infection estimates from incidence data were consistent with those previously estimated from seroprevalence data. The baseline reporting rate (or the probability of detecting a secondary infection) was generally low (<25%) and varied within and between countries. Conclusions/Significance As expected, estimates varied widely across and within countries, highlighting the spatio-temporally heterogeneous nature of dengue transmission. Although seroprevalence data provide the maximum information, the incidence models presented in this paper provide a method for estimating dengue transmission intensity from age-stratified incidence data, which will be an important consideration in areas where seroprevalence data are not available. PMID:27399793

  1. Transmission of Mycobacterium tuberculosis in a High School and School-Based Supervision of an Isoniazid-Rifapentine Regimen for Preventing Tuberculosis - Colorado, 2011-2012.

    PubMed

    2013-10-01

    Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB), is spread from person to person by the airborne route. It can be transmitted extensively in congregate settings, making investigating exposures and treating infected contacts challenging. In December 2011, a student at a Colorado high school with 1,381 students and school personnel received a diagnosis of pulmonary TB disease. One of five household contacts had TB disease, and the other four had latent M. tuberculosis infection (LTBI). Screening of 1,249 school contacts (90%) found one person with pulmonary TB disease, who was fully treated, and 162 with LTBI, of whom 159 started an LTBI treatment regimen for preventing progression to TB disease and 153 completed a regimen. Only the index patient required inpatient care for TB, and TB caused no deaths. Use of short-course treatment regimens, either 12-dose weekly isoniazid and rifapentine directly observed at school or 4 months of self-supervised rifampin daily, facilitated treatment completion. State and county incident command structures led by county TB control authorities guided a response team from multiple jurisdictions. News media reports brought public scrutiny, but meetings with the community addressed the concerns and enhanced public participation. Two contacts of the index patient outside of the school had TB disease diagnosed after the school investigation. As of July 2013, no additional TB disease associated with in-school exposure had been found. An emergency plan for focusing widespread resources, an integral public communications strategy, and new, efficient interventions should be considered in other large TB contact investigations. PMID:24080593

  2. Protocol for a population-based molecular epidemiology study of tuberculosis transmission in a high HIV-burden setting: the Botswana Kopanyo study

    PubMed Central

    Zetola, N M; Modongo, C; Moonan, P K; Click, E; Oeltmann, J E; Shepherd, J; Finlay, A

    2016-01-01

    Introduction Mycobacterium tuberculosis (Mtb) is transmitted from person to person via airborne droplet nuclei. At the community level, Mtb transmission depends on the exposure venue, infectiousness of the tuberculosis (TB) index case and the susceptibility of the index case's social network. People living with HIV infection are at high risk of TB, yet the factors associated with TB transmission within communities with high rates of TB and HIV are largely undocumented. The primary aim of the Kopanyo study is to better understand the demographic, clinical, social and geospatial factors associated with TB and multidrug-resistant TB transmission in 2 communities in Botswana, a country where 60% of all patients with TB are also infected with HIV. This manuscript describes the methods used in the Kopanyo study. Methods and analysis The study will be conducted in greater Gaborone, which has high rates of HIV and a mobile population; and in Ghanzi, a rural community with lower prevalence of HIV infection and home to the native San population. Kopanyo aims to enrol all persons diagnosed with TB during a 4-year study period. From each participant, sputum will be cultured, and for all Mtb isolates, molecular genotyping (24-locus mycobacterial interspersed repetitive units-variable number of tandem repeats) will be performed. Patients with matching genotype results will be considered members of a genotype cluster, a proxy for recent transmission. Demographic, behavioural, clinical and social information will be collected by interview. Participant residence, work place, healthcare facilities visited and social gathering venues will be geocoded. We will assess relationships between these factors and cluster involvement to better plan interventions for reducing TB transmission. Ethics Ethical approval from the Independent Review Boards at the University of Pennsylvania, US Centers for Disease Control and Prevention, Botswana Ministry of Health and University of Botswana has been

  3. High Rates of Potentially Infectious Tuberculosis and Multidrug-Resistant Tuberculosis (MDR-TB) among Hospital Inpatients in KwaZulu Natal, South Africa Indicate Risk of Nosocomial Transmission

    PubMed Central

    Bantubani, Nonkqubela; Kabera, Gaetan; Connolly, Catherine; Rustomjee, Roxana; Reddy, Tarylee; Cohen, Ted; Pym, Alexander S.

    2014-01-01

    Background Nosocomial transmission has been implicated as a key factor in the outbreak of extensively drug resistant (XDR) and multidrug-resistant (MDR-TB) tuberculosis at Church of Scotland Hospital (CoSH), in KwaZulu-Natal (KZN), South Africa. The aim of this study was to quantify the burden of potentially infectious tuberculosis and the proportion of drug resistance among hospital inpatients throughout the province of KZN. Methods Inpatients with current cough, capable of producing sputum were selected from 19 public hospitals in KZN. After informed consent, demographic and clinical data, and sputum samples were collected. Samples were processed for fluorescent microscopy, liquid culture and first and second-line anti-tuberculosis drug susceptibility testing. Results There were a total of 2,964 inpatients where sampling was done. About 1,585 inpatients (53%) had a current cough and sufficient microbiological and clinical data for inclusion. Mycobacterium tuberculosis was isolated from 543 inpatients (34% of those tested and 18% of all inpatients). Eighty-four (15%) inpatients with TB were found to be MDR-TB infected and 16 (3%) had XDR-TB. There was no association between the prevalence of MDR-TB and proximity to CoSH. Among patients with microbiologically confirmed TB, MDR/XDR-TB was associated with male sex, a longer length of stay between hospital admission and date of sample collection, and current or previous TB treatment. Conclusions One in five inpatients had potentially infectious TB. This is an underestimate since patients without current cough were not tested. MDR-TB was frequently observed and was found in nearly one in six active TB inpatients. While present at lower levels than the original outbreak report at CoSH, XDR-TB was detected in hospitals throughout KZN. The high burden of potentially infectious TB and confirmed MDR-TB, much of it undiagnosed, indicates a serious risk for nosocomial transmission and the need for intensified infection

  4. [Future prospects of molecular epidemiology in tuberculosis].

    PubMed

    Matsumoto, Tomoshige; Iwamoto, Tomotada

    2009-12-01

    Before the availability of high-resolution genotyping tools in 1990s, there was a prevailing dogma of little genomic sequence diversity in Mycobacterium tuberculosis. Due to the low levels of genetic variation, it was assumed that M. tuberculosis exhibit very little phenotypic variation in immunologic and virulence factors. The fingerprinting method based on restriction fragment length polymorphisms (RFLP) of IS6110 insertion sequences had unveiled the underestimation of the sequence variation in M. tuberculosis and the importance of strain-to-strain variation for understanding pathogenesis, immune mechanisms, bacterial evolution, and host adaptation. This method became a gold standard for strain differentiation in the molecular epidemiological study. It had lead to a profusion of studies in molecular epidemiology such as the detection of unsuspected transmission, the estimation of the extent of recent transmission, the identification of laboratory cross-contamination, the identification of outbreaks, and distinction between reinfection and relapse. This, in 1990s, is the opening of the molecular epidemiology of tuberculosis. After the completion of genome project of the M. tuberculosis laboratory strain H37Rv, some of the clinical isolates were completely sequenced. This prompted the in silico genome comparison and identified various genomic markers which can give a unifying framework for both epidemiology and evolutionary analysis of M. tuberculosis population. Of them, variable numbers of tandem repeats (VNTR) was found as the most promising PCR-based method which can provide adequate discrimination of M. tuberculosis strains in many cases, including the estimation of M. tuberculosis transmission and the identification of genetic lineages. PCR-based VNTR analysis is easy, rapid, and highly specific and can generate portable digit-based data, unlike the analog information obtained from IS6110 RFLP which is labor intensive. In this regards, investigators can

  5. Tracing Mycobacterium tuberculosis transmission by whole genome sequencing in a high incidence setting: a retrospective population-based study in East Greenland.

    PubMed

    Bjorn-Mortensen, K; Soborg, B; Koch, A; Ladefoged, K; Merker, M; Lillebaek, T; Andersen, A B; Niemann, S; Kohl, T A

    2016-01-01

    In East Greenland, a dramatic increase of tuberculosis (TB) incidence has been observed in recent years. Classical genotyping suggests a genetically similar Mycobacterium tuberculosis (Mtb) strain population as cause, however, precise transmission patterns are unclear. We performed whole genome sequencing (WGS) of Mtb isolates from 98% of culture-positive TB cases through 21 years (n = 182) which revealed four genomic clusters of the Euro-American lineage (mainly sub-lineage 4.8 (n = 134)). The time to the most recent common ancestor of lineage 4.8 strains was found to be 100 years. This sub-lineage further diversified in the 1970s, and massively expanded in the 1990s, a period of lowered TB awareness in Greenland. Despite the low genetic strain diversity, WGS data revealed several recent short-term transmission events in line with the increasing incidence in the region. Thus, the isolated setting and the uniformity of circulating Mtb strains indicated that the majority of East Greenlandic TB cases originated from one or few strains introduced within the last century. Thereby, the study shows the consequences of even short interruptions in TB control efforts in previously TB high incidence areas and demonstrates the potential role of WGS in detecting ongoing micro epidemics, thus guiding public health efforts in the future. PMID:27615360

  6. Estimating Dengue Transmission Intensity from Sero-Prevalence Surveys in Multiple Countries

    PubMed Central

    Imai, Natsuko; Dorigatti, Ilaria; Cauchemez, Simon; Ferguson, Neil M.

    2015-01-01

    Background Estimates of dengue transmission intensity remain ambiguous. Since the majority of infections are asymptomatic, surveillance systems substantially underestimate true rates of infection. With advances in the development of novel control measures, obtaining robust estimates of average dengue transmission intensity is key for assessing both the burden of disease from dengue and the likely impact of interventions. Methodology/Principal Findings The force of infection (λ) and corresponding basic reproduction numbers (R0) for dengue were estimated from non-serotype (IgG) and serotype-specific (PRNT) age-stratified seroprevalence surveys identified from the literature. The majority of R0 estimates ranged from 1–4. Assuming that two heterologous infections result in complete immunity produced up to two-fold higher estimates of R0 than when tertiary and quaternary infections were included. λ estimated from IgG data were comparable to the sum of serotype-specific forces of infection derived from PRNT data, particularly when inter-serotype interactions were allowed for. Conclusions/Significance Our analysis highlights the highly heterogeneous nature of dengue transmission. How underlying assumptions about serotype interactions and immunity affect the relationship between the force of infection and R0 will have implications for control planning. While PRNT data provides the maximum information, our study shows that even the much cheaper ELISA-based assays would provide comparable baseline estimates of overall transmission intensity which will be an important consideration in resource-constrained settings. PMID:25881272

  7. Estimating transmissivity and storage properties from aquifer tests in the Southern Lihue Basin, Kauai, Hawaii

    USGS Publications Warehouse

    Gingerich, Stephen B.

    1999-01-01

    The results show that transmissivity in the Lihue basin ranges over several orders of magnitude, 42 to 7,900 square feet per day, but is generally lower than reported values of transmissivity of other basaltic aquifers in Hawaii. Estimates of confined-aquifer storage coefficient range from 1.3x10-4 to 8.2x10-2. The hydraulic conductivity estimates obtained using an elliptical-equation method compare favorably with the results obtained from the generally more-accepted curvematching methods. No significant difference is apparent between the estimated transmissivity of the Koloa Volcanics and the Waimea Canyon Basalt in the study area. An analysis of the lithology penetrated by the wells indicates the transmissivity is probably controlled mainly by the stratigraphic position of the layers penetrated by the well. The range of transmissivity values estimated for the southern Lihue basin is lower than reported values from aquifer tests at wells penetrating postshield-stage or rejuvenation-stage lava flows on other Hawaiian islands. This range is one to four orders of magnitude lower than most reported values for dike-free basalt aquifers in Hawaii.

  8. Estimating transmissivity from single-well pumping tests in heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Pechstein, Armin; Attinger, Sabine; Krieg, Ronald; Copty, Nadim K.

    2016-01-01

    Although aquifers are naturally heterogeneous, the interpretation of pumping tests is commonly performed under the assumption of aquifer homogeneity. This yields interpreted hydraulic parameters averaged over a domain of uncertain extent which disguises their relation to the underlying heterogeneity. In this study, we numerically investigate the sensitivity of the transient drawdown at the pumping well, to nonuniform distributions of transmissivity in confined aquifers. Frechet kernels and their time derivative are used to estimate two spatially averaged transmissivities, denoted the equivalent and interpreted transmissivity, Teq and Tin, respectively, for the case of single-well pumping tests. Interrelating Teq and Tin is achieved by modeling Tin in terms of a distance dependent, radially heterogeneous field. In weakly heterogeneous aquifers, Teq approximates TPW, the local transmissivity at the pumped well. With increasing degree of heterogeneity, Teq deviates from TPW as pumping propagates. Tin starts at TPW, approaching the spatial geometric mean of transmissivity during late pumping times. Limits of the proposed spatial weighting functions are investigated by treating the interpreted storativity, Sest, as an indicator for flow connectivity. It is shown numerically that the spatial weights for Teq and Tin agree well to the underlying heterogeneity if . Finally, implications for applying the concepts of Teq and Tin to heterogeneous domains, and, for real world applications are discussed. It is found that time-dependent spatial averages of Tin agree well with estimates of the interpreted transmissivity from the Continuous-Derivation method.

  9. X-ray spectrum estimation from transmission measurements by an exponential of a polynomial model

    NASA Astrophysics Data System (ADS)

    Perkhounkov, Boris; Stec, Jessika; Sidky, Emil Y.; Pan, Xiaochuan

    2016-04-01

    There has been much recent research effort directed toward spectral computed tomography (CT). An important step in realizing spectral CT is determining the spectral response of the scanning system so that the relation between material thicknesses and X-ray transmission intensity is known. We propose a few parameter spectrum model that can accurately model the X-ray transmission curves and has a form which is amenable to simultaneous spectral CT image reconstruction and CT system spectrum calibration. While the goal is to eventually realize the simultaneous image reconstruction/spectrum estimation algorithm, in this work we investigate the effectiveness of the model on spectrum estimation from simulated transmission measurements through known thicknesses of known materials. The simulated transmission measurements employ a typical X-ray spectrum used for CT and contain noise due to the randomness in detecting finite numbers of photons. The proposed model writes the X-ray spectrum as the exponential of a polynomial (EP) expansion. The model parameters are obtained by use of a standard software implementation of the Nelder-Mead simplex algorithm. The performance of the model is measured by the relative error between the predicted and simulated transmission curves. The estimated spectrum is also compared with the model X-ray spectrum. For reference, we also employ a polynomial (P) spectrum model and show performance relative to the proposed EP model.

  10. Joint estimation of transmissivities and recharges—application: stochastic characterization of well capture zones

    NASA Astrophysics Data System (ADS)

    Franssen, Harrie-Jan Hendricks; Stauffer, Fritz; Kinzelbach, Wolfgang

    2004-07-01

    This paper is concerned about aquifer models that are affected by the uncertainty on hydraulic conductivity and recharge. In particular, we study the impact of these sources of uncertainty on the stochastic characterization of drinking water well capture zones. The estimation of a drinking water well capture zone is important for the design of a protection zone around the well. The estimation is associated with uncertainty due to imperfect knowledge of the input parameters of the groundwater flow and mass transport equations. A first synthetic study shows that the uncertainty of the mean recharge has a larger impact on the well catchment uncertainty than the uncertainty of the spatial variability of recharge. Therefore, it is concluded that in practice the recharge can be estimated for one zone or a limited number of zones, without the need to estimate the recharge on the grid cell scale. The sequential self-calibrated method for the Monte Carlo type inverse modelling of groundwater flow and mass transport was extended for the estimation of recharge rates. Recharge rates can be estimated together with hydraulic conductivities, and possibly other parameters, using both head and concentration data. In a second synthetic study the joint estimation of transmissivities and recharge rates is illustrated. It is found that the transmissivity, hydraulic head and recharge fields are better characterised after the inverse conditioning. In order to stabilize the inverse estimation, it is essential that a regularization term is included in the objective function in case parameters are estimated zone-wise.

  11. Cost estimation of HVDC transmission system of Bangka’s NPP candidates

    SciTech Connect

    Liun, Edwaren Suparman

    2014-09-30

    Regarding nuclear power plant development in Bangka Island, it can be estimated that produced power will be oversupply for the Bangka Island and needs to transmit to Sumatra or Java Island. The distance between the regions or islands causing considerable loss of power in transmission by alternating current, and a wide range of technical and economical issues. The objective of this paper addresses to economics analysis of direct current transmission system to overcome those technical problem. Direct current transmission has a stable characteristic, so that the power delivery from Bangka to Sumatra or Java in a large scale efficiently and reliably can be done. HVDC system costs depend on the power capacity applied to the system and length of the transmission line in addition to other variables that may be different.

  12. Estimating Transmissivity from the Water Level Fluctuations of a Sinusoidally Forced Well

    USGS Publications Warehouse

    Mehnert, E.; Valocchi, A.J.; Heidari, M.; Kapoor, S.G.; Kumar, P.

    1999-01-01

    The water levels in wells are known to fluctuate in response to earth tides and changes in atmospheric pressure. These water level fluctuations can be analyzed to estimate transmissivity (T). A new method to estimate transmissivity, which assumes that the atmospheric pressure varies in a sinusoidal fashion, is presented. Data analysis for this simplified method involves using a set of type curves and estimating the ratio of the amplitudes of the well response over the atmospheric pressure. Type curves for this new method were generated based on a model for ground water flow between the well and aquifer developed by Cooper et al. (1965). Data analysis with this method confirmed these published results: (1) the amplitude ratio is a function of transmissivity, the well radius, and the frequency of the sinusoidal oscillation; and (2) the amplitude ratio is a weak function of storativity. Compared to other methods, the developed method involves simpler, more intuitive data analysis and allows shorter data sets to be analyzed. The effect of noise on estimating the amplitude ratio was evaluated and found to be more significant at lower T. For aquifers with low T, noise was shown to mask the water level fluctuations induced by atmospheric pressure changes. In addition, reducing the length of the data series did not affect the estimate of T, but the variance of the estimate was higher for the shorter series of noisy data.

  13. Estimating the Magnitude and Direction of Altered Arbovirus Transmission Due to Viral Phenotype

    PubMed Central

    Christofferson, Rebecca C.; Mores, Christopher N.

    2011-01-01

    Vectorial capacity is a measure of the transmission potential of a vector borne pathogen within a susceptible population. Vector competence, a component of the vectorial capacity equation, is the ability of an arthropod to transmit an infectious agent following exposure to that agent. Comparisons of arbovirus strain-specific vector competence estimates have been used to support observed or hypothesized differences in transmission capability. Typically, such comparisons are made at a single time point during the extrinsic incubation period, the time in days it takes for the virus to replicate and disseminate to the salivary glands. However, vectorial capacity includes crucial parameters needed to effectively evaluate transmission capability, though often this is based on the discrete vector competence values. Utilization of the rate of change of vector competence over a range of days gives a more accurate measurement of the transmission potential. Accordingly, we investigated the rate of change in vector competence of dengue virus in Aedes aegypti mosquitoes and the resulting vectorial capacity curves. The areas under the curves represent the effective vector competence and the cumulative transmission potentials of arboviruses within a population of mosquitoes. We used the calculated area under the curve for each virus strain and the corresponding variance estimates to test for differences in cumulative transmission potentials between strains of dengue virus based on our dynamic model. To further characterize differences between dengue strains, we devised a displacement index interpreted as the capability of a newly introduced strain to displace the established, dominant circulating strain. The displacement index can be used to better understand the transmission dynamics in systems where multiple strains/serotypes circulate or even multiple arbovirus species. The use of a rate of a rate of change based model of vectorial capacity and the informative calculations of

  14. Estimation of torque transmitted by clutch during shifting process for dry dual clutch transmission

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiguo; He, Lu; Yang, Yunyun; Wu, Chaochun; Li, Xueyan; Karl Hedrick, J.

    2016-06-01

    The key toward realizing no-impact gear shifting for dual clutch transmission (DCT) lies in the coordination control between the engine and dual clutches, as well as the accurate closed-loop control of torque transmitted by each clutch and the output torque of the engine. However, the implementation and control precision of closed-loop control are completely dependent on the effective measurement or estimation of the instant transmission torque of the clutch. This study analyzes the DCT shifting process, and builds a three-dimensional (3D) clutch model and mathematical model of a DCT vehicle powertrain system. The torque transmitted by a twin clutch during the upshifting process is estimated by applying the unscented Kalman filter (UKF) algorithm. Then, the torque estimation algorithm is verified using a DCT prototype vehicle installed with a torque sensor on the drive half-shaft. The experimental results show that the designed UKF torque estimation algorithm can estimate the transmission torques of two clutches in real time; further, it can be directly used for DCT shift control and improving the shifting quality.

  15. Estimating the transmission potential of supercritical processes based on the final size distribution of minor outbreaks

    PubMed Central

    Nishiura, Hiroshi; Yan, Ping; Sleeman, Candace K.; Mode, Charles J.

    2011-01-01

    Use of the final size distribution of minor outbreaks for the estimation of the reproduction numbers of supercritical epidemic processes has yet to be considered. We used a branching process model to derive the final size distribution of minor outbreaks, assuming a reproduction number above unity, and applying the method to final size data for pneumonic plague. Pneumonic plague is a rare disease with only one documented major epidemic in a spatially limited setting. Because the final size distribution of a minor outbreak needs to be normalized by the probability of extinction, we assume that the dispersion parameter (k) of the negative-binomial offspring distribution is known, and examine the sensitivity of the reproduction number to variation in dispersion. Assuming a geometric offspring distribution with k = 1, the reproduction number was estimated at 1.16 (95% confidence interval: 0.97–1.38). When less dispersed with k = 2, the maximum likelihood estimate of the reproduction number was 1.14. These estimates agreed with those published from transmission network analysis, indicating that the human-to-human transmission potential of the pneumonic plague is not very high. Given only minor outbreaks, transmission potential is not sufficiently assessed by directly counting the number of offspring. Since the absence of a major epidemic does not guarantee a subcritical process, the proposed method allows us to conservatively regard epidemic data from minor outbreaks as supercritical, and yield estimates of threshold values above unity. PMID:22079419

  16. Estimating Drivers of Autochthonous Transmission of Chikungunya Virus in its Invasion of the Americas

    PubMed Central

    Perkins, T. Alex; Metcalf, C. Jessica E.; Grenfell, Bryan T.; Tatem, Andrew J.

    2015-01-01

    Background Chikungunya is an emerging arbovirus that has caused explosive outbreaks in Africa and Asia for decades and invaded the Americas just over a year ago. During this ongoing invasion, it has spread to 45 countries where it has been transmitted autochthonously, infecting nearly 1.3 million people in total. Methods Here, we made use of weekly, country-level case reports to infer relationships between transmission and two putative climatic drivers: temperature and precipitation averaged across each country on a monthly basis. To do so, we used a TSIR model that enabled us to infer a parametric relationship between climatic drivers and transmission potential, and we applied a new method for incorporating a probabilistic description of the serial interval distribution into the TSIR framework. Results We found significant relationships between transmission and linear and quadratic terms for temperature and precipitation and a linear term for log incidence during the previous pathogen generation. The lattermost suggests that case numbers three to four weeks ago are largely predictive of current case numbers. This effect is quite nonlinear at the country level, however, due to an estimated mixing parameter of 0.74. Relationships between transmission and the climatic variables that we estimated were biologically plausible and in line with expectations. Conclusions Our analysis suggests that autochthonous transmission of Chikungunya in the Americas can be correlated successfully with putative climatic drivers, even at the coarse scale of countries and using long-term average climate data. Overall, this provides a preliminary suggestion that successfully forecasting the future trajectory of a Chikungunya outbreak and the receptivity of virgin areas may be possible. Our results also provide tentative estimates of timeframes and areas of greatest risk, and our extension of the TSIR model provides a novel tool for modeling vector-borne disease transmission. PMID:25737803

  17. Estimating drivers of autochthonous transmission of chikungunya virus in its invasion of the americas.

    PubMed

    Perkins, T Alex; Metcalf, C Jessica E; Grenfell, Bryan T; Tatem, Andrew J

    2015-01-01

    Background Chikungunya is an emerging arbovirus that has caused explosive outbreaks in Africa and Asia for decades and invaded the Americas just over a year ago. During this ongoing invasion, it has spread to 45 countries where it has been transmitted autochthonously, infecting nearly 1.3 million people in total. Methods Here, we made use of weekly, country-level case reports to infer relationships between transmission and two putative climatic drivers: temperature and precipitation averaged across each country on a monthly basis. To do so, we used a TSIR model that enabled us to infer a parametric relationship between climatic drivers and transmission potential, and we applied a new method for incorporating a probabilistic description of the serial interval distribution into the TSIR framework. Results We found significant relationships between transmission and linear and quadratic terms for temperature and precipitation and a linear term for log incidence during the previous pathogen generation. The lattermost suggests that case numbers three to four weeks ago are largely predictive of current case numbers. This effect is quite nonlinear at the country level, however, due to an estimated mixing parameter of 0.74. Relationships between transmission and the climatic variables that we estimated were biologically plausible and in line with expectations. Conclusions Our analysis suggests that autochthonous transmission of Chikungunya in the Americas can be correlated successfully with putative climatic drivers, even at the coarse scale of countries and using long-term average climate data. Overall, this provides a preliminary suggestion that successfully forecasting the future trajectory of a Chikungunya outbreak and the receptivity of virgin areas may be possible. Our results also provide tentative estimates of timeframes and areas of greatest risk, and our extension of the TSIR model provides a novel tool for modeling vector-borne disease transmission. PMID:25737803

  18. Vegetation Height Estimation Near Power transmission poles Via satellite Stereo Images using 3D Depth Estimation Algorithms

    NASA Astrophysics Data System (ADS)

    Qayyum, A.; Malik, A. S.; Saad, M. N. M.; Iqbal, M.; Abdullah, F.; Rahseed, W.; Abdullah, T. A. R. B. T.; Ramli, A. Q.

    2015-04-01

    Monitoring vegetation encroachment under overhead high voltage power line is a challenging problem for electricity distribution companies. Absence of proper monitoring could result in damage to the power lines and consequently cause blackout. This will affect electric power supply to industries, businesses, and daily life. Therefore, to avoid the blackouts, it is mandatory to monitor the vegetation/trees near power transmission lines. Unfortunately, the existing approaches are more time consuming and expensive. In this paper, we have proposed a novel approach to monitor the vegetation/trees near or under the power transmission poles using satellite stereo images, which were acquired using Pleiades satellites. The 3D depth of vegetation has been measured near power transmission lines using stereo algorithms. The area of interest scanned by Pleiades satellite sensors is 100 square kilometer. Our dataset covers power transmission poles in a state called Sabah in East Malaysia, encompassing a total of 52 poles in the area of 100 km. We have compared the results of Pleiades satellite stereo images using dynamic programming and Graph-Cut algorithms, consequently comparing satellites' imaging sensors and Depth-estimation Algorithms. Our results show that Graph-Cut Algorithm performs better than dynamic programming (DP) in terms of accuracy and speed.

  19. Comparing methods for estimating R0 from the size distribution of subcritical transmission chains

    PubMed Central

    Blumberg, S.; Lloyd-Smith, J.O.

    2013-01-01

    Many diseases exhibit subcritical transmission (i.e. 0 < R0 < 1) so that infections occur as self-limited ‘stuttering chains’. Given an ensemble of stuttering chains, information about the number of cases in each chain can be used to infer R0, which is of crucial importance for monitoring the risk that a disease will emerge to establish endemic circulation. However, the challenge of imperfect case detection has led authors to adopt a variety of work-around measures when inferring R0, such as discarding data on isolated cases or aggregating intermediate-sized chains together. Each of these methods has the potential to introduce bias, but a quantitative comparison of these approaches has not been reported. By adapting a model based on a negative binomial offspring distribution that permits a variable degree of transmission heterogeneity, we present a unified analysis of existing R0 estimation methods. Simulation studies show that the degree of transmission heterogeneity, when improperly modeled, can significantly impact the bias of R0 estimation methods designed for imperfect observation. These studies also highlight the importance of isolated cases in assessing whether an estimation technique is consistent with observed data. Analysis of data from measles outbreaks shows that likelihood scores are highest for models that allow a flexible degree of transmission heterogeneity. Aggregating intermediate sized chains often has similar performance to analyzing a complete chain size distribution. However, truncating isolated cases is beneficial only when surveillance systems clearly favor full observation of large chains but not small chains. Meanwhile, if data on the type and proportion of cases that are unobserved were known, we demonstrate that maximum likelihood inference of R0 could be adjusted accordingly. This motivates the need for future empirical and theoretical work to quantify observation error and incorporate relevant mechanisms into stuttering chain

  20. Exposed, but Not Protected: More Is Needed to Prevent Drug-Resistant Tuberculosis in Healthcare Workers and Students.

    PubMed

    von Delft, Arne; Dramowski, Angela; Sifumba, Zolelwa; Mosidi, Thato; Xun Ting, Tiong; von Delft, Dalene; Zumla, Alimuddin

    2016-05-15

    "Occupational MDR-TB"  …  "XDR-TB"  …  "Treatment-induced hearing loss": 3 life-changing messages imparted over the phone. Three personal accounts are shared highlighting the false belief held by many healthcare workers (HCWs) and students in low-resource settings-that they are immune to tuberculosis despite high levels of occupational tuberculosis exposure. This misconception reflects a lack of awareness of tuberculosis transmission and disease risk, compounded by the absence of accurate occupational tuberculosis estimates. As the global problem of drug-resistant (DR) tuberculosis evolves, HCWs are increasingly infected and suffer considerable morbidity and mortality from occupational DR tuberculosis disease. Similarly, healthcare students are emerging as a vulnerable and unprotected group. There is an urgent need for improved detection, vaccines, preventive therapy, treatment, and support for affected HCWs and those they care for, as well as destigmatization of all forms of tuberculosis. Finally, efforts to protect HCWs and prevent DR tuberculosis transmission by universal implementation of tuberculosis infection control measures should be prioritized. PMID:27118858

  1. Estimation of Ten-Year Survival of Patients with Pulmonary Tuberculosis Based on the Competing Risks Model in Iran

    PubMed Central

    Kazempour-Dizaji, Mehdi; Tabarsi, Payam; Zayeri, Farid

    2016-01-01

    Background: Tuberculosis (TB) is a chronic bacterial disease, which despite the presence of effective drug strategies, still remains a serious health problem worldwide. Estimation of survival rate is an appropriate indicator for prognosis in patients with pulmonary TB. Therefore, this research was designed with the aim of accurate estimation of the survival of patients by taking both the death event and relapse into consideration. Materials and Methods: Based on a retrospective cohort study, information of 2,299 patients with pulmonary TB that had been referred to and treated in Masih Daneshvari Hospital from 2005 to 2015 was reviewed. To estimate the survival of patients with pulmonary TB, the competing risks model, which considered death and relapse as competing events, was used. In addition, the effect of factors affecting the cumulative incidence function (CIF) of death event and relapse was also examined. Results: The effect of risk factors on the CIF of death events and relapse showed that patients’ age, marital status, contact with TB patients, adverse effect of drugs, imprisonment and HIV positivity were factors that affected the CIF of death. Meanwhile, sex, marital status, imprisonment and HIV positivity were factors affecting the CIF of relapse (P <0.05). Considering death and relapse as competing events, survival estimation in pulmonary TB patients showed that survival in this group of patients in the first, third, fifth and tenth year after treatment was 39%, 14%, 7% and 0%, respectively. Conclusion: The use of competing risks model in survival analysis of patients with pulmonary TB with consideration of competing events, enables more accurate estimation of survival. PMID:27403177

  2. Gay men's estimates of the likelihood of HIV transmission in sexual behaviours.

    PubMed

    Gold, R S; Skinner, M J

    2001-04-01

    In 3 studies we recorded gay men's estimates of the likelihood that HIV would be transmitted in various sexual behaviours. In Study 1 (data collected 1993, n=92), the men were found to believe that transmissibility is very much greater than it actually is; that insertive unprotected anal intercourse (UAI) by an HIV-infected partner is made safer by withdrawal before ejaculation, and very much safer by withdrawal before either ejaculation or pre-ejaculation; that UAI is very much safer when an infected partner is receptive rather than insertive; that insertive oral sex by an infected partner is much less risky than even the safest variant of UAI; that HIV is less transmissible very early after infection than later on; and that risk accumulates over repeated acts of UAI less than it actually does. In Study 2 (data collected 1997/8, n=200), it was found that younger and older uninfected men generally gave similar estimates of transmissibility, but that infected men gave somewhat lower estimates than uninfected men; and that estimates were unaffected by asking the men to imagine that they themselves, rather than a hypothetical other gay man, were engaging in the behaviours. Comparison of the 1993 and 1997/8 results suggested that there had been some effect of an educational campaign warning of the dangers of withdrawal; however, there had been no effect either of a campaign warning of the dangers of receptive UAI by an infected partner, or of publicity given to the greater transmissibility of HIV shortly after infection. In Study 3 (data collected 1999, n=59), men induced into a positive mood were found to give lower estimates of transmissibility than either men induced into a neutral mood or men induced into a negative mood. It is argued that the results reveal the important contribution made to gay men's transmissibility estimates by cognitive strategies (such as the 'availability heuristic' and 'anchoring and adjustment') known to be general characteristics of human

  3. An indirect transmission measurement-based spectrum estimation method for computed tomography

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Niu, Kai; Schafer, Sebastian; Royalty, Kevin

    2015-01-01

    The characteristics of an x-ray spectrum can greatly influence imaging and related tasks. In practice, due to the pile-up effect of the detector, it’s difficult to directly measure the spectrum of a CT scanner using an energy resolved detector. An alternative solution is to estimate the spectrum using transmission measurements with a step phantom or another CT phantom. In this work, we present a new spectrum estimation method based on indirect transmission measurement and a model spectra mixture approach. The estimated x-ray spectrum was expressed as a weighted summation of a set of model spectra, which can significantly reduce the degrees of freedom of the spectrum estimation problem. Next, an estimated projection was calculated with the assumed spectrum. By iteratively updating the unknown weights, we minimized the difference between the estimated projection data and the raw projection data. The final spectrum was calculated with these calibrated weights and the model spectra. Both simulation and experimental data were used to evaluate the proposed method. In the simulation study, the estimated spectra were compared to the raw spectra which were used to generate the raw projection data. For the experimental study, the ground truth measurement of the raw x-ray spectrum was not available. Therefore, the estimated spectrum was compared against the spectra generated using the SpekCalc software with tube configurations provided by the scanner manufacturer. The results show the proposed method has the potential to accurately estimate x-ray spectra using the raw projection data. The difference between the mean energy of the raw spectra and the mean energy of the estimated spectra was less than 0.5 keV for both the simulation and experimental data. Further tests show the method was robust with respect to the model spectra generator.

  4. Epidemiology and Treatment of Multidrug Resistant Tuberculosis

    PubMed Central

    Mitnick, Carole D.; Appleton, Sasha C.; Shin, Sonya S.

    2010-01-01

    Multidrug resistant tuberculosis is now thought to afflict between 1 and 2 million patients annually. Although significant regional variability in the distribution of disease has been recorded, surveillance data are limited by several factors. The true burden of disease is likely underestimated. Nevertheless, the estimated burden is substantial enough to warrant concerted action. A range of approaches is possible, but all appropriate interventions require scale-up of laboratories and early treatment with regimens containing a sufficient number of second-line drugs. Ambulatory treatment for most patients, and improved infection control, can facilitate scale-up with decreased risk of nosocomial transmission. Several obstacles have been considered to preclude worldwide scale-up of treatment, mostly attributable to inadequate human, drug, and financial resources. Further delays in scale-up, however, risk continued generation and transmission of resistant tuberculosis, as well as associated morbidity and mortality. PMID:18810684

  5. Estimating Contact Process Saturation in Sylvatic Transmission of Trypanosoma cruzi in the United States

    PubMed Central

    Kribs-Zaleta, Christopher

    2010-01-01

    Although it has been known for nearly a century that strains of Trypanosoma cruzi, the etiological agent for Chagas' disease, are enzootic in the southern U.S., much remains unknown about the dynamics of its transmission in the sylvatic cycles that maintain it, including the relative importance of different transmission routes. Mathematical models can fill in gaps where field and lab data are difficult to collect, but they need as inputs the values of certain key demographic and epidemiological quantities which parametrize the models. In particular, they determine whether saturation occurs in the contact processes that communicate the infection between the two populations. Concentrating on raccoons, opossums, and woodrats as hosts in Texas and the southeastern U.S., and the vectors Triatoma sanguisuga and Triatoma gerstaeckeri, we use an exhaustive literature review to derive estimates for fundamental parameters, and use simple mathematical models to illustrate a method for estimating infection rates indirectly based on prevalence data. Results are used to draw conclusions about saturation and which population density drives each of the two contact-based infection processes (stercorarian/bloodborne and oral). Analysis suggests that the vector feeding process associated with stercorarian transmission to hosts and bloodborne transmission to vectors is limited by the population density of vectors when dealing with woodrats, but by that of hosts when dealing with raccoons and opossums, while the predation of hosts on vectors which drives oral transmission to hosts is limited by the population density of hosts. Confidence in these conclusions is limited by a severe paucity of data underlying associated parameter estimates, but the approaches developed here can also be applied to the study of other vector-borne infections. PMID:20436914

  6. Link-state-estimation-based transmission power control in wireless body area networks.

    PubMed

    Kim, Seungku; Eom, Doo-Seop

    2014-07-01

    This paper presents a novel transmission power control protocol to extend the lifetime of sensor nodes and to increase the link reliability in wireless body area networks (WBANs). We first experimentally investigate the properties of the link states using the received signal strength indicator (RSSI). We then propose a practical transmission power control protocol based on both short- and long-term link-state estimations. Both the short- and long-term link-state estimations enable the transceiver to adapt the transmission power level and target the RSSI threshold range, respectively, to simultaneously satisfy the requirements of energy efficiency and link reliability. Finally, the performance of the proposed protocol is experimentally evaluated in two experimental scenarios-body posture change and dynamic body motion-and compared with the typical WBAN transmission power control protocols, a real-time reactive scheme, and a dynamic postural position inference mechanism. From the experimental results, it is found that the proposed protocol increases the lifetime of the sensor nodes by a maximum of 9.86% and enhances the link reliability by reducing the packet loss by a maximum of 3.02%. PMID:24107988

  7. Estimating methane releases from natural gas production and transmission in Russia

    NASA Astrophysics Data System (ADS)

    Dedikov, J. V.; Akopova (Vniigaz), G. S.; Gladkaja (Vniigaz), N. G.; Piotrovskij (Tyumentransgaz), A. S.; Markellov (Volgotransgaz), V. A.; Salichov (Yamburggazdabuicha), S. S.; Kaesler, H.; Ramm, A.; Müller von Blumencron, A.; Lelieveld, J.

    Methane releases from the RAO Gazprom gas production and transmission facilities in Russia were determined in an extensive measurement program carried out in 1996 and 1997. Subsequently, the measurements were extrapolated to the Russian scale. The results show that methane releases from gas transmission are less than 1% of throughput. Methane loss from gas production in northwestern Siberia appears to be relatively small, generally less than 0.1%. The largest methane emissions result from venting during maintenance and repairs, leaks from valves on transmission lines, and from compressor stations. The measurements show that, in the case of leaks, a limited number of major ones accounts for most of the methane releases. Methane emissions expressed as a percentage of the gas volume produced or transported are (rounded figures): production and processing 0.1%, pipelines 0.2%, compressor stations 0.7%, so that the total release by production and transmission in Russia amounts to about 1.0%, i.e. ˜5.4×10 9 m 3/a (˜4 Tg/a). This is consistent with our previous preliminary estimates, indicating that maximum emissions are 1.5-1.8%/a. However, this is generally lower than most other estimates and speculations.

  8. An EM algorithm for estimating SPECT emission and transmission parameters from emissions data only.

    PubMed

    Krol, A; Bowsher, J E; Manglos, S H; Feiglin, D H; Tornai, M P; Thomas, F D

    2001-03-01

    A maximum-likelihood (ML) expectation-maximization (EM) algorithm (called EM-IntraSPECT) is presented for simultaneously estimating single photon emission computed tomography (SPECT) emission and attenuation parameters from emission data alone. The algorithm uses the activity within the patient as transmission tomography sources, with which attenuation coefficients can be estimated. For this initial study, EM-IntraSPECT was tested on computer-simulated attenuation and emission maps representing a simplified human thorax as well as on SPECT data obtained from a physical phantom. Two evaluations were performed. First, to corroborate the idea of reconstructing attenuation parameters from emission data, attenuation parameters (mu) were estimated with the emission intensities (lambda) fixed at their true values. Accurate reconstructions of attenuation parameters were obtained. Second, emission parameters lambda and attenuation parameters mu were simultaneously estimated from the emission data alone. In this case there was crosstalk between estimates of lambda and mu and final estimates of lambda and mu depended on initial values. Estimates degraded significantly as the support extended out farther from the body, and an explanation for this is proposed. In the EM-IntraSPECT reconstructed attenuation images, the lungs, spine, and soft tissue were readily distinguished and had approximately correct shapes and sizes. As compared with standard EM reconstruction assuming a fix uniform attenuation map, EM-IntraSPECT provided more uniform estimates of cardiac activity in the physical phantom study and in the simulation study with tight support, but less uniform estimates with a broad support. The new EM algorithm derived here has additional applications, including reconstructing emission and transmission projection data under a unified statistical model. PMID:11341711

  9. Application of satellite estimates of rainfall distribution to simulate the potential for malaria transmission in Africa

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Eltahir, E. A.

    2009-12-01

    The Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS) is a mechanistic model developed to assess malaria risk in areas where the disease is water-limited. This model relies on precipitation inputs as its primary forcing. Until now, applications of the model have used ground-based precipitation observations. However, rain gauge networks in the areas most affected by malaria are often sparse. The increasing availability of satellite based rainfall estimates could greatly extend the range of the model. The minimum temporal resolution of precipitation data needed was determined to be one hour. The CPC Morphing technique (CMORPH ) distributed by NOAA fits this criteria, as it provides 30-minute estimates at 8km resolution. CMORPH data were compared to ground observations in four West African villages, and calibrated to reduce overestimation and false alarm biases. The calibrated CMORPH data were used to force HYDREMATS, resulting in outputs for mosquito populations, vectorial capacity and malaria transmission.

  10. Evaluating use of cattle winter feeding areas by elk and white-tailed deer: implications for managing bovine tuberculosis transmission risk from the ground up.

    PubMed

    Brook, Ryan K; Wal, Eric Vander; van Beest, Floris M; McLachlan, Stéphane M

    2013-02-01

    Transmission of bovine tuberculosis (Mycobacterium bovis) among wildlife and livestock has created important risks for conservation and agriculture. Management strategies aimed at controlling TB have typically been top-down, regionally focused, and government-led programs that were at best only partially successful. The purpose of this study was to quantify co-mingling of elk and white-tailed deer (WTD) with cattle at multiple spatial scales (i.e., the regional farm scale and winter cattle feeding area patch) in southwestern Manitoba, Canada, to assess the potential for bovine tuberculosis transmission and identify alternative management strategies. For each spatial scale we quantified use of cattle farms by elk and white-tailed deer. We mailed questionnaires to rural households and then conducted personal interviews with 86 cattle farmers to map the spatial distribution of their cattle winter feeding areas at a fine scale. We deployed Global Positioning System (GPS) collars on 48 wild elk and 16 wild white-tailed deer from 2003 to 2011. Elk were observed on farms by 66% of cattle producers, including 5% and 20% who observed direct and indirect contact, respectively, between elk and cattle. Cattle producers consistently (≈100%) observed white-tailed deer on their farms, including 11% and 47% whom observed direct and indirect contact, respectively, between white-tailed deer and cattle. A higher probability of white-tailed deer-cattle contact at the regional scale occurs on farms that (1) left crop residues specifically for wildlife, (2) had larger cattle herds, (3) used round bale feeders, and (4) were farther away from protected areas. None of the GPS-collared elk locations overlapped with cattle winter feeding areas. In contrast, 21% of GPS-collared white-tailed deer locations overlapped with winter cattle winter feeding areas (22% of these were from male WTD and 78% were from female WTD). White-tailed deer selected cattle winter feeding areas with higher (1

  11. Estimating risks of importation and local transmission of Zika virus infection

    PubMed Central

    Nah, Kyeongah; Mizumoto, Kenji; Miyamatsu, Yuichiro; Yasuda, Yohei; Kinoshita, Ryo

    2016-01-01

    Background. An international spread of Zika virus (ZIKV) infection has attracted global attention. ZIKV is conveyed by a mosquito vector, Aedes species, which also acts as the vector species of dengue and chikungunya viruses. Methods. Arrival time of ZIKV importation (i.e., the time at which the first imported case was diagnosed) in each imported country was collected from publicly available data sources. Employing a survival analysis model in which the hazard is an inverse function of the effective distance as informed by the airline transportation network data, and using dengue and chikungunya virus transmission data, risks of importation and local transmission were estimated. Results. A total of 78 countries with imported case(s) have been identified, with the arrival time ranging from 1 to 44 weeks since the first ZIKV was identified in Brazil, 2015. Whereas the risk of importation was well explained by the airline transportation network data, the risk of local transmission appeared to be best captured by additionally accounting for the presence of dengue and chikungunya viruses. Discussion. The risk of importation may be high given continued global travel of mildly infected travelers but, considering that the public health concerns over ZIKV infection stems from microcephaly, it is more important to focus on the risk of local and widespread transmission that could involve pregnant women. The predicted risk of local transmission was frequently seen in tropical and subtropical countries with dengue or chikungunya epidemic experience. PMID:27069825

  12. Estimating risks of importation and local transmission of Zika virus infection.

    PubMed

    Nah, Kyeongah; Mizumoto, Kenji; Miyamatsu, Yuichiro; Yasuda, Yohei; Kinoshita, Ryo; Nishiura, Hiroshi

    2016-01-01

    Background. An international spread of Zika virus (ZIKV) infection has attracted global attention. ZIKV is conveyed by a mosquito vector, Aedes species, which also acts as the vector species of dengue and chikungunya viruses. Methods. Arrival time of ZIKV importation (i.e., the time at which the first imported case was diagnosed) in each imported country was collected from publicly available data sources. Employing a survival analysis model in which the hazard is an inverse function of the effective distance as informed by the airline transportation network data, and using dengue and chikungunya virus transmission data, risks of importation and local transmission were estimated. Results. A total of 78 countries with imported case(s) have been identified, with the arrival time ranging from 1 to 44 weeks since the first ZIKV was identified in Brazil, 2015. Whereas the risk of importation was well explained by the airline transportation network data, the risk of local transmission appeared to be best captured by additionally accounting for the presence of dengue and chikungunya viruses. Discussion. The risk of importation may be high given continued global travel of mildly infected travelers but, considering that the public health concerns over ZIKV infection stems from microcephaly, it is more important to focus on the risk of local and widespread transmission that could involve pregnant women. The predicted risk of local transmission was frequently seen in tropical and subtropical countries with dengue or chikungunya epidemic experience. PMID:27069825

  13. A Novel Approach - The Propensity to Propagate (PTP) Method for Controlling for Host Factors in Studying the Transmission of Mycobacterium Tuberculosis

    PubMed Central

    Nebenzahl-Guimaraes, Hanna; Borgdorff, Martien W.; Murray, Megan B.; van Soolingen, Dick

    2014-01-01

    Rationale Understanding the genetic variations among Mycobacterium tuberculosis (MTB) strains with differential ability to transmit would be a major step forward in preventing transmission. Objectives To describe a method to extend conventional proxy measures of transmissibility by adjusting for patient-related factors, thus strengthening the causal association found with bacterial factors. Methods Clinical, demographic and molecular fingerprinting data were obtained during routine surveillance of verified MTB cases reported in the Netherlands between 1993 and 2011, and the phylogenetic lineages of the isolates were inferred. Odds ratios for host risk factors for clustering were used to obtain a measure of each patient's and cluster's propensity to propagate (CPP). Mean and median cluster sizes across different categories of CPP were compared amongst four different phylogenetic lineages. Results Both mean and median cluster size grew with increasing CPP category. On average, CPP values from Euro-American lineage strains were higher than Beijing and EAI strains. There were no significant differences between the mean and median cluster sizes among the four phylogenetic lineages within each CPP category. Conclusions Our finding that the distribution of CPP scores was unequal across four different phylogenetic lineages supports the notion that host-related factors should be controlled for to attain comparability in measuring the different phylogenetic lineages' ability to propagate. Although Euro-American strains were more likely to be in clusters in an unadjusted analysis, no significant differences among the four lineages persisted after we controlled for host factors. PMID:24849817

  14. Tuberculosis outbreak in a housing unit for human immunodeficiency virus-infected patients in a correctional facility: transmission risk factors and effective outbreak control.

    PubMed

    Mohle-Boetani, Janet C; Miguelino, Vanessa; Dewsnup, Daniel H; Desmond, Edward; Horowitz, Evalyn; Waterman, Stephen H; Bick, Joseph

    2002-03-01

    In 1995, an outbreak of tuberculosis (TB) occurred among residents of a correctional-facility housing unit for inmates infected with human immunodeficiency virus (HIV). We isolated and treated patients who were suspected to have TB. To determine risk factors for in-prison transmission of TB, we conducted a case-control study to compare inmate case patients infected with a distinct outbreak strain of TB with control subjects who resided in the HIV unit. We identified 15 case patients during a 4-month period. Among inmates with a CD4 count of <100 cells/mm(3), case patients were more likely than control subjects to spend >/=20 hours per week in a communal day room (odds ratio, 42; P=.002) and were less likely to have a television in their single-person room (odds ratio, 0.10; P=.003). The communal day room was a likely site of transmission. Successful collaboration between the correctional system and public health departments halted the outbreak. PMID:11803502

  15. Estimating the variance and integral scale of the transmissivity field using head residual increments

    USGS Publications Warehouse

    Zheng, Lingyun; Silliman, S.E.

    2000-01-01

    A modification of previously published solutions regarding the spatial variation of hydraulic heads is discussed whereby the semivariogram of increments of head residuals (termed head residual increments HRIs) are related to the variance and integral scale of the transmissivity field. A first-order solution is developed for the case of a transmissivity field which is isotropic and whose second-order behavior can be characterized by an exponential covariance structure. The estimates of the variance ??(Y)/2 and the integral scale ?? of the log transmissivity field are then obtained via fitting a theoretical semivariogram for the HRI to its sample semivariogram. This approach is applied to head data sampled from a series of two-dimensional, simulated aquifers with isotropic, exponential covariance structures and varying degrees of heterogeneity (??(Y)/2 = 0.25, 0.5, 1.0, 2.0, and 5.0). The results show that this method provided reliable estimates for both ?? and ??(Y)/2 in aquifers with the value of ??(Y)/2 up to 2.0, but the errors in those estimates were higher for ??(Y)/2 equal to 5.0. It is also demonstrated through numerical experiments and theoretical arguments that the head residual increments will provide a sample semivariogram with a lower variance than will the use of the head residuals without calculation of increments.

  16. Design and cost estimate of an 800 MVA superconducting power transmission

    SciTech Connect

    Alex, P.; Ernst, A. ); Forsyth, E.; Gibbs, R.; Thomas, R.; Muller, T. )

    1990-10-18

    Numerous studies involving cost estimates have been performed for superconducting power transmission systems. As these systems were usually aimed at providing transmission from large clusters of generation the base power rating of the corridor was very high; in the case of the most comprehensive study it was 10,000 MVA. The purpose of this study is to examine a system which is very closely based on the prototype 1000 MVA system which was operated at Brookhaven National Laboratory over a four year period. The purpose of the study is to provide cost estimates for the superconducting system and to compare these estimates with a design based on the use of advanced but conventional cable designs. The work is supported by funding from the Office of Energy Research's Industry/Laboratory Technology Exchange Program. This program is designed to commercialize energy technologies. The technical design of the superconducting system was prepared by the BNL staff, the design of the 800 MVA conventional cable system was done by engineers from Underground Systems Incorporated. Both institutions worked on the cost estimate of the superconducting system. The description and cost estimate of the conventional cable system is given in the Appendix. 5 refs.

  17. An angle-dependent estimation of CT x-ray spectrum from rotational transmission measurements

    SciTech Connect

    Lin, Yuan Samei, Ehsan; Ramirez-Giraldo, Juan Carlos; Gauthier, Daniel J.; Stierstorfer, Karl

    2014-06-15

    Purpose: Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors propose an angle-dependent estimation technique, where the incident spectra across a wide range of angular trajectories can be estimated accurately with only a single phantom and a single axial scan in the absence of the knowledge of the bowtie filter. Methods: The proposed technique uses a uniform cylindrical phantom, made of ultra-high-molecular-weight polyethylene and positioned in an off-centered geometry. The projection data acquired with an axial scan have a twofold purpose. First, they serve as a reflection of the transmission measurements across different angular trajectories. Second, they are used to reconstruct the cross sectional image of the phantom, which is then utilized to compute the intersection length of each transmission measurement. With each CT detector element recording a range of transmission measurements for a single angular trajectory, the spectrum is estimated for that trajectory. A data conditioning procedure is used to combine information from hundreds of collected transmission measurements to accelerate the estimation speed, to reduce noise, and to improve estimation stability. The proposed spectral estimation technique was validated experimentally using a clinical scanner (Somatom Definition Flash, Siemens Healthcare, Germany) with spectra provided by the manufacturer serving as the comparison standard. Results obtained with the proposed technique were compared against those obtained from a second conventional transmission measurement technique with two materials (i.e., Cu and Al). After validation, the proposed technique was applied to measure

  18. Binary prefix for sampling frequency offset estimation in dispersive optical transmissions.

    PubMed

    Cheng, Lin; Liu, Xiang; Chand, Naresh; Effenberger, Frank; Chang, Gee-Kung

    2015-10-01

    We propose and experimentally demonstrate a method for sampling frequency offset (SFO) estimation in optical communication systems based on periodically inserted identical binary prefix. Different from conventional cyclic prefix, binary prefix provides not only high tolerance to chromatic dispersion in dispersive fiber transmission, but also the ability to estimate SFO by simple receiver-side digital signal processing. Moreover, this binary prefix based scheme is generally applicable to any advanced modulation formats. A proof-of-concept experiment is conducted to quantify the accuracy and tolerance of the scheme in estimating SFO. It is found that over a wide SFO range up to 341 ppm, the estimation error is kept under 20 ppb and signals are recovered with the same quality as with zero-offset sampling. The experimental results also confirm that this method is tolerant to link signal-to-noise ratio loss and dispersion, showing no additional penalty after transmission over a 40-km standard single-mode fiber at 1550 nm. PMID:26480132

  19. How good are estimates of transmissivity from slug tests in fractured rock?

    USGS Publications Warehouse

    Shapiro, A.M.; Hsieh, P.A.

    1998-01-01

    Slug tests in fractured rock usually are interpreted with models that assume homogeneous formation properties, even though hydraulic properties of fractures can vary by many orders of magnitude over the length of boreholes. To investigate the impact of heterogeneity on the interpretation of slug tests in fractured rock, slug tests were conducted over large intervals of boreholes in crystalline rock in central New Hampshire, and interpreted using a homogeneous model. The results of the slug tests were then compared with estimates of transmissivity from fluid-injection tests conducted over shorter intervals in the same boreholes. The fluid-injection tests showed transmissivity to vary more than six orders of magnitude over the length of the boreholes; however, the sum of the transmissivities from the fluid-injection tests were within an order of magnitude of the transmissivity estimated from the slug tests. Although the two estimates of transmissivity were within an order of magnitude of each other, the water level responses during the slug tests did not exactly match the responses predicted by the homogeneous model. To investigate the effect of heterogeneity on water level responses during slug tests, a Laplace-transform solution was developed for slug tests conducted in boreholes containing multiple fractures with hydraulic properties that vary over the length of the borehole. A comparison of this solution with the homogeneous model shows no difference between the shape of water level responses in a homogeneous formation and a (layered) heterogeneous formation. Furthermore, the transmissivity estimated using a homogeneous model is within an order of magnitude of the prescribed transmissivity in the heterogeneous model. Thus, differences between responses predicted from a homogeneous model and measured water levels during slug tests can be attributed to phenomena such as nonradial flow in the vicinity of the borehole, and not heterogeneous hydraulic properties over

  20. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

    PubMed Central

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. PMID:27399715

  1. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands.

    PubMed

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. PMID:27399715

  2. On-Farm Mitigation of Transmission of Tuberculosis from White-Tailed Deer to Cattle: Literature Review and Recommendations

    PubMed Central

    Walter, W. David; Anderson, Charles W.; Smith, Rick; Vanderklok, Mike; Averill, James J.; VerCauteren, Kurt C.

    2012-01-01

    The Animal Industry Division of the Michigan Department of Agriculture and Rural Development (MDARD) has been challenged with assisting farmers with modifying farm practices to reduce potential for exposure to Mycobacterium bovis from wildlife to cattle. The MDARD recommendations for on-farm risk mitigation practices were developed from experiences in the US, UK and Ireland and a review of the scientific literature. The objectives of our study were to review the present state of knowledge on M. bovis excretion, transmission, and survival in the environment and the interactions of wildlife and cattle with the intention of determining if the current recommendations by MDARD on farm practices are adequate and to identify additional changes to farm practices that may help to mitigate the risk of transmission. This review will provide agencies with a comprehensive summary of the scientific literature on mitigation of disease transmission between wildlife and cattle and to identify lacunae in published research. PMID:22991687

  3. The use of streambed temperatures to estimate transmission losses on an experimental channel.

    SciTech Connect

    Ramon C. Naranjo; Michael H. Young; Richard Niswonger; Julianne J. Miller; Richard H. French

    2001-10-18

    Quantifying channel transmission losses in arid environments is important for a variety of reasons, from engineering design of flood control structures to evaluating recharge. To quantify the losses in an alluvial channel, an experiment was performed on a 2-km reach of an alluvial fan located on the Nevada Test Site. The channel was subjected to three separate flow events. Transmission losses were estimated using standard discharge monitoring and subsurface temperature modeling approach. Four stations were equipped to continuously monitor stage, temperature, and water content. Streambed temperatures measured at 0, 30, 50 and 100 cm depths were used to calibrate VS2DH, a two-dimensional, variably saturated flow model. Average losses based on the difference in flow between each station indicate that 21 percent, 27 percent, and 53 percent of the flow was reduced downgradient of the source. Results from the temperature monitoring identified locations with large thermal gradients, suggesting a conduction-dominated heat transfer on streambed sediments where caliche-cemented surfaces were present. Transmission losses at the lowermost segment corresponded to the smallest thermal gradient, suggesting an advection-dominated heat transfer. Losses predicted by VS2DH are within an order of magnitude of the estimated losses based on discharge measurements. The differences in losses are a result of the spatial extent to which the modeling results are applied and lateral subsurface flow.

  4. An Update on Global Tuberculosis (TB)

    PubMed Central

    Talip, Balkis A.; Sleator, Roy D.; Lowery, Colm J.; Dooley, James S.G.; Snelling, William J.

    2013-01-01

    Tuberculosis globally results in almost 2 million human deaths annually, with 1 in 4 deaths from tuberculosis being human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)-related. Primarily a pathogen of the respiratory system, aerobic Mycobacterium tuberculosis complex (MTBC) infects the lungs via the inhalation of infected aerosol droplets generated by people with pulmonary disease through coughing. This review focuses on M. tuberculosis transmission, epidemiology, detection methods and technologies. PMID:24847176

  5. Population Estimation and Trappability of the European Badger (Meles meles): Implications for Tuberculosis Management

    PubMed Central

    Byrne, Andrew W.; O’Keeffe, James; Green, Stuart; Sleeman, D. Paddy; Corner, Leigh A. L.; Gormley, Eamonn; Murphy, Denise; Martin, S. Wayne; Davenport, John

    2012-01-01

    Estimates of population size and trappability inform vaccine efficacy modelling and are required for adaptive management during prolonged wildlife vaccination campaigns. We present an analysis of mark-recapture data from a badger vaccine (Bacille Calmette–Guérin) study in Ireland. This study is the largest scale (755 km2) mark-recapture study ever undertaken with this species. The study area was divided into three approximately equal–sized zones, each with similar survey and capture effort. A mean badger population size of 671 (SD: 76) was estimated using a closed-subpopulation model (CSpM) based on data from capturing sessions of the entire area and was consistent with a separate multiplicative model. Minimum number alive estimates calculated from the same data were on average 49–51% smaller than the CSpM estimates, but these are considered severely negatively biased when trappability is low. Population densities derived from the CSpM estimates were 0.82–1.06 badgers km−2, and broadly consistent with previous reports for an adjacent area. Mean trappability was estimated to be 34–35% per session across the population. By the fifth capture session, 79% of the adult badgers caught had been marked previously. Multivariable modelling suggested significant differences in badger trappability depending on zone, season and age-class. There were more putatively trap-wary badgers identified in the population than trap-happy badgers, but wariness was not related to individual’s sex, zone or season of capture. Live-trapping efficacy can vary significantly amongst sites, seasons, age, or personality, hence monitoring of trappability is recommended as part of an adaptive management regime during large–scale wildlife vaccination programs to counter biases and to improve efficiencies. PMID:23227211

  6. Terabit Nyquist PDM-32QAM signal transmission with training sequence based time domain channel estimation.

    PubMed

    Zhang, Fan; Wang, Dan; Ding, Rui; Chen, Zhangyuan

    2014-09-22

    We propose a time domain structure of channel estimation for coherent optical communication systems, which employs training sequence based equalizer and is transparent to arbitrary quadrature amplitude modulation (QAM) formats. Enabled with this methodology, 1.02 Tb/s polarization division multiplexed 32 QAM Nyquist pulse shaping signal with a net spectral efficiency of 7.46 b/s/Hz is transmitted over standard single-mode fiber link with Erbium-doped fiber amplifier only amplification. After 1190 km transmission, the average bit-error rate is lower than the 20% hard-decision forward error correction threshold of 1.5 × 10(-2). The transmission distance can be extended to 1428 km by employing intra-subchannel nonlinear compensation with the digital back-propagation method. PMID:25321810

  7. Tuberculosis Infection in the United States: Prevalence Estimates from the National Health and Nutrition Examination Survey, 2011-2012

    PubMed Central

    Miramontes, Roque; Hill, Andrew N.; Yelk Woodruff, Rachel S.; Lambert, Lauren A.; Navin, Thomas R.; Castro, Kenneth G.; LoBue, Philip A.

    2015-01-01

    Background Reexamining the prevalence of persons infected with tuberculosis (TB) is important to determine trends over time. In 2011–2012 a TB component was included in the National Health and Nutrition Examination Survey (NHANES) to estimate the reservoir of persons infected with TB. Methods Civilian, noninstitutionalized U.S. population survey participants aged 6 years and older were interviewed regarding their TB history and eligibility for the tuberculin skin test (TST) and interferon gamma release assay (IGRA) blood test. Once eligibility was confirmed, both tests were conducted. Prevalence and numbers of TST positive (10 mm or greater), IGRA positive, and both TST and IGRA positive were calculated by adjusting for the complex survey design after applying corrections for item nonresponse and digit preference in TST induration measurements. To examine TST positivity over time, data from NHANES 1999–2000 were reanalyzed using the same statistical methods. The TST was performed using Tubersol, a commercially available purified protein derivative (PPD), rather than PPD-S, which was the antigen used in NHANES 1999–2000. Prior patient history of TB vaccination was not collected in this study nor were patients examined for the presence of a Bacillus of Calmette and Guerin (BCG) vaccine scar. Results For NHANES 2011–2012, TST and IGRA results were available for 6,128 (78.4%) and 7,107 (90.9%) eligible participants, respectively. There was no significant difference between the percentage of the U.S. population that was TST positive in 2011–2012 (4.7% [95% CI 3.4–6.3]; 13,276,000 persons) compared with 1999–2000 (4.3%; 3.5–5.3). In 2011–2012 the percentage that was IGRA positive was 5.0% (4.2–5.8) and double TST and IGRA positivity was 2.1% (1.5–2.8). The point estimate of IGRA positivity prevalence in foreign-born persons (15.9%; 13.5–18.7) was lower than for TST (20.5%; 16.1–25.8) in 2011–2012. The point estimate of IGRA positivity

  8. A Full-Bayesian Approach to the Estimation of Transmissivity Fields From Thermal Data

    NASA Astrophysics Data System (ADS)

    Jiang, Y.; Woodbury, A. D.

    2002-12-01

    Woodbury and Ulrych (WRR 36(8), 2000) proposed a Full-Bayesian approach to the estimation of transmissivity from hydraulic head and transmissivity measurements for two-dimensional steady state groundwater flow. Specifically, Bayesian updating (see Woodbury, 1989) was used to condition prior estimates of logarithm transmissivity [denoted as ln (T)] field with ln (T) measurements. Then they incorporated hydraulic head measurements into the updating procedure by adopting a linearized aquifer equation. Prior probability density functions (pdfs) of the ln (T) field and any hyperparameters associated with its two central moments were determined from maximum entropy considerations. Any uncertainties in the basic geostatistical hyperparameters were removed by marginalization. Woodbury and Ulrych (2000) showed that the resolution of the ln (T) field gradually improved through the updating procedure. In their work the problem was discretized very finely so that many more unknowns than data points are sought. In this way the heterogeneous nature of the porous media is more reasonably approximated. The Bayesian methodology reformulates this ill-posed inverse of deduction into a well-posed problem of inference. With this approach one can take advantage of data from different sources and any knowledge of the identified system can help constraint the inverse problem. In this work the full-Bayesian approach is extended to estimate transmissivity field from thermal data. Linearized treatment to the advection-conduction heat transport leads to a linear formulation between temperature and ln (T) perturbations. An updating procedure similar to that of Woodbury and Ulrych (2000) can be performed. This new algorithm is examined against a generic example. It is found that the use of temperature data is showed to improve the ln (T) estimates, in comparison to the updated ln (T) field conditioned on spare ln (T) and head data; also the addition of temperature data without head data to the

  9. Tuberculosis on the flight deck.

    PubMed

    Parmet, A J

    1999-08-01

    Tuberculosis in commercial aircraft has been a concern since a 1995 incident of possible transmission from an active case of tuberculosis to passengers in the cabin of a 747. Subsequently, commercial air carriers have been vigilant in cooperating with public health authorities in tracking all known exposures to tuberculosis. In 1998, a pilot of a commercial airliner was diagnosed with active tuberculosis. Company records demonstrated that in the previous 6 mo, the pilot had flown with 48 other pilots. Every exposed pilot was contacted and evaluated by skin testing (IPPD) or chest x-ray if previously positive. There were no skin test conversions and no changes on x-rays. This study demonstrates that transmission of tuberculosis in the aircraft cabin environment, even under close and continuous exposure to an active case, is a rare event. PMID:10447057

  10. Simultaneous emission and transmission scanning in PET oncology: The effect on parameter estimation

    SciTech Connect

    Meikle, S.R.; Eberl, S.; Hooper, P.K.; Fulham, M.J.

    1997-02-01

    The authors investigated potential sources of bias due to simultaneous emission and transmission (SET) scanning and their effect on parameter estimation in dynamic positron emission tomography (PET) oncology studies. The sources of bias considered include: (i) variation in transmission spillover (into the emission window) throughout the field of view, (ii) increased scatter arising from rod sources, and (iii) inaccurate deadtime correction. Net bias was calculated as a function of the emission count rate and used to predict distortion in [{sup 18}F]2-fluoro-2-deoxy-D-glucose (FDG) and [{sup 11}C]thymidine tissue curves simulating the normal liver and metastatic involvement of the liver. The effect on parameter estimates was assessed by spectral analysis and compartmental modeling. The various sources of bias approximately cancel during the early part of the study when count rate is maximal. Scatter dominates in the latter part of the study, causing apparently decreased tracer clearance which is more marked for thymidine than for FDG. The irreversible disposal rate constant, K{sub i}, was overestimated by <10% for FDG and >30% for thymidine. The authors conclude that SET has a potential role in dynamic FDG PET-but is not suitable for {sup 11}C-labeled compounds.

  11. A Dynamic Model of Human and Livestock Tuberculosis Spread and Control in Urumqi, Xinjiang, China

    PubMed Central

    Liu, Shan; Li, Aiqiao; Feng, Xiaomei; Zhang, Xueliang

    2016-01-01

    We establish a dynamical model for tuberculosis of humans and cows. For the model, we firstly give the basic reproduction number R0. Furthermore, we discuss the dynamical behaviors of the model. By epidemiological investigation of tuberculosis among humans and livestock from 2007 to 2014 in Urumqi, Xinjiang, China, we estimate the parameters of the model and study the transmission trend of the disease in Urumqi, Xinjiang, China. The reproduction number in Urumqi for the model is estimated to be 0.1811 (95% confidence interval: 0.123–0.281). Finally, we perform some sensitivity analysis of several model parameters and give some useful comments on controlling the transmission of tuberculosis. PMID:27525034

  12. Estimation of outer-middle ear transmission using DPOAEs and fractional-order modeling of human middle ear

    NASA Astrophysics Data System (ADS)

    Naghibolhosseini, Maryam

    Our ability to hear depends primarily on sound waves traveling through the outer and middle ear toward the inner ear. Hence, the characteristics of the outer and middle ear affect sound transmission to/from the inner ear. The role of the middle and outer ear in sound transmission is particularly important for otoacoustic emissions (OAEs), which are sound signals generated in a healthy cochlea, and recorded by a sensitive microphone placed in the ear canal. OAEs are used to evaluate the health and function of the cochlea; however, they are also affected by outer and middle ear characteristics. To better assess cochlear health using OAEs, it is critical to quantify the impact of the outer and middle ear on sound transmission. The reported research introduces a noninvasive approach to estimate outer-middle ear transmission using distortion product otoacoustic emissions (DPOAEs). In addition, the role of the outer and middle ear on sound transmission was investigated by developing a physical/mathematical model, which employed fractional-order lumped elements to include the viscoelastic characteristics of biological tissues. Impedance estimations from wideband refectance measurements were used for parameter fitting of the model. The model was validated comparing its estimates of the outer-middle ear sound transmission with those given by DPOAEs. The outer-middle ear transmission by the model was defined as the sum of forward and reverse outer-middle ear transmissions. To estimate the reverse transmission by the model, the probe-microphone impedance was calculated through estimating the Thevenin-equivalent circuit of the probe-microphone. The Thevenin-equivalent circuit was calculated using measurements in a number of test cavities. Such modeling enhances our understanding of the roles of different parts of the outer and middle ear and how they work together to determine their function. In addition, the model would be potentially helpful in diagnosing pathologies of

  13. Ocular tuberculosis: current perspectives

    PubMed Central

    Shakarchi, Faiz I

    2015-01-01

    The World Health Organization currently estimates that nearly two billion people, or one-third of the world’s population, are infected by tuberculosis, and that roughly 10% of the infected people are symptomatic. Tuberculosis affects the lungs in 80% of patients, while in the remaining 20% the disease may affect other organs, including the eye. Uveitis can be seen concurrently with tuberculosis, but a direct association is difficult to prove. Ocular tuberculosis is usually not associated with clinical evidence of pulmonary tuberculosis, as up to 60% of extrapulmonary tuberculosis patients may not have pulmonary disease. The diagnosis of tuberculous uveitis is often problematic and in nearly all reported cases, the diagnosis was only presumptive. Tuberculous uveitis is a great mimicker of various uveitis entities and it can be considered in the differential diagnosis of any type of intraocular inflammation. It is still unknown if ocular manifestations result from a direct mycobacterium infection or hypersensitivity reaction and this is reflected on the management of tuberculous uveitis. Prevalence of tuberculosis as an etiology of uveitis may reach up to 10% in endemic areas. Tuberculous uveitis is a vision-threatening disease that inevitably leads to blindness if not properly diagnosed and treated. The aim of this review is to illustrate the various clinical features and management of presumed tuberculous uveitis. The current review focuses on the diagnostic criteria, significance of tuberculin skin test, and use of systemic corticosteroids in the management of tuberculous uveitis as recommended in recent publications. PMID:26648690

  14. The history of tuberculosis.

    PubMed

    Daniel, Thomas M

    2006-11-01

    Tuberculosis has claimed its victims throughout much of known human history. It reached epidemic proportions in Europe and North America during the 18th and 19th centuries, earning the sobriquet, "Captain Among these Men of Death." Then it began to decline. Understanding of the pathogenesis of tuberculosis began with the work of Théophile Laennec at the beginning of the 19th century and was further advanced by the demonstration of the transmissibility of Mycobacterium tuberculosis infection by Jean-Antoine Villemin in 1865 and the identification of the tubercle bacillus as the etiologic agent by Robert Koch in 1882. Clemens von Pirquet developed the tuberculin skin test in 1907 and 3 years later used it to demonstrate latent tuberculous infection in asymptomatic children. In the late 19th and early 20th centuries sanatoria developed for the treatment of patients with tuberculosis. The rest provided there was supplemented with pulmonary collapse procedures designed to rest infected parts of lungs and to close cavities. Public Health measures to combat the spread of tuberculosis emerged following the discovery of its bacterial cause. BCG vaccination was widely employed following World War I. The modern era of tuberculosis treatment and control was heralded by the discovery of streptomycin in 1944 and isoniazid in 1952. PMID:16949809

  15. Controlling the seedbeds of tuberculosis: diagnosis and treatment of tuberculosis infection.

    PubMed

    Rangaka, Molebogeng X; Cavalcante, Solange C; Marais, Ben J; Thim, Sok; Martinson, Neil A; Swaminathan, Soumya; Chaisson, Richard E

    2015-12-01

    The billions of people with latent tuberculosis infection serve as the seedbeds for future cases of active tuberculosis. Virtually all episodes of tuberculosis disease are preceded by a period of asymptomatic Mycobacterium tuberculosis infection; therefore, identifying infected individuals most likely to progress to disease and treating such subclinical infections to prevent future disease provides a crucial opportunity to interrupt tuberculosis transmission and reduce the global burden of tuberculosis disease. Programmes focusing on single strategies rather than comprehensive programmes that deliver an integrated arsenal for tuberculosis control might continue to struggle. Tuberculosis preventive therapy is a poorly used method that is essential for controlling the reservoirs of disease that drive the epidemic. Comprehensive control strategies that combine preventive therapy for the most high-risk populations and communities with improved case-finding and treatment, control of transmission, and health systems strengthening could ultimately lead to worldwide tuberculosis elimination. In this Series paper we outline challenges to implementation of preventive therapy and provide pragmatic suggestions for overcoming them. We further advocate for tuberculosis preventive therapy as the core of a renewed worldwide focus to implement a comprehensive epidemic control strategy that would reduce new tuberculosis cases to elimination targets. This strategy would be underpinned by accelerated research to further understand the biology of subclinical tuberculosis infections, develop novel diagnostics and drug regimens specifically for subclinical tuberculosis infection, strengthen health systems and community engagement, and enhance sustainable large scale implementation of preventive therapy programmes. PMID:26515679

  16. Eradication of bovine tuberculosis at a herd-level in Madrid, Spain: study of within-herd transmission dynamics over a 12 year period

    PubMed Central

    2012-01-01

    Background Eradication of bovine tuberculosis (bTB) through the application of test-and-cull programs is a declared goal of developed countries in which the disease is still endemic. Here, longitudinal data from more than 1,700 cattle herds tested during a 12 year-period in the eradication program in the region of Madrid, Spain, were analyzed to quantify the within-herd transmission coefficient (β) depending on the herd-type (beef/dairy/bullfighting). In addition, the probability to recover the officially bTB free (OTF) status in infected herds depending on the type of herd and the diagnostic strategy implemented was assessed using Cox proportional hazard models. Results Overall, dairy herds showed higher β (median 4.7) than beef or bullfighting herds (2.3 and 2.2 respectively). Introduction of interferon-gamma (IFN-γ) as an ancillary test produced an apparent increase in the β coefficient regardless of production type, likely due to an increase in diagnostic sensitivity. Time to recover OTF status was also significantly lower in dairy herds, and length of bTB episodes was significantly reduced when the IFN-γ was implemented to manage the outbreak. Conclusions Our results suggest that bTB spreads more rapidly in dairy herds compared to other herd types, a likely cause being management and demographic-related factors. However, outbreaks in dairy herds can be controlled more rapidly than in typically extensive herd types. Finally, IFN-γ proved its usefulness to rapidly eradicate bTB at a herd-level. PMID:22748007

  17. Tuberculosis (TB)

    MedlinePlus

    ... Skip Content Marketing Share this: Main Content Area Tuberculosis Research The New Challenge for TB Research NIAID ... HIV/AIDS Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis Research Agenda (PDF) TB Research at NIAID Research ...

  18. Tuberculosis (TB)

    MedlinePlus

    ... Skip Content Marketing Share this: Main Content Area Tuberculosis (TB) Overview In developed countries, such as the ... thought to be infected with TB bacteria, Mycobacterium tuberculosis ( Mtb ). TB is a chronic bacterial infection. It ...

  19. Estimating transmissivity fields and their influence on flow and transport: The case of Champagne mounts

    NASA Astrophysics Data System (ADS)

    Renard, F.; JeannéE, N.

    2008-11-01

    This paper presents a flexible and general methodology that combines hydrogeological and geostatistical modeling techniques to estimate a set of transmissivity fields and their influence on flow and transport. The methodology may be applied to any case with only hydraulic head observations, even if most of them are concentrated inside a small part of the entire domain of interest. It is applied here to the case of the Champagne chalk aquifer (France), where it is shown to be very efficient. The methodology is decomposed in three independent parts. First, a reference head distribution is constructed by kriging in order to constrain the inverse problem. As hydraulic heads and elevations are correlated, a smoothed digital elevation model is used as external drift. The inverse problem is then solved by using a simplified pilot point method with an efficient and easy-to-use minimization algorithm. Finally, geostatistical simulations combined with flow simulations lead to a set of acceptable transmissivity fields. The induced uncertainty is evaluated by calculating tracer concentrations, pointing out areas where flow behavior is uncertain and where new borings would be advantageously drilled.

  20. Estimating frame bulk and shear moduli of two double porosity layers by ultrasound transmission.

    PubMed

    Bai, Ruonan; Tinel, Alain; Alem, Abdellah; Franklin, Hervé; Wang, Huaqing

    2016-08-01

    The acoustic plane wave transmission by water saturated double porosity media is investigated. Two samples of double porosity media assumed to obey Berryman and Wang (BW) extension (Berryman and Wang, 1995, 2000) of Biot's theory in the low frequency regime are under consideration: ROBU® (pure binder-free borosilicate glass 3.3 manufactured to form the individual grains) and Tobermorite 11Å (the individual porous cement grains show irregular shapes). The de facto gap existing between theoretical and experimental data can be minimized by modifying adequately two of the parameters estimated from triaxial tests: the frame bulk and shear moduli. The frequency dependent imaginary parts that follow necessary from the minimization are in relation with the energy losses due to contact relaxation and friction between grains. PMID:27209582

  1. Bovine Tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tuberculosis (TB) in animals and humans may result from exposure to bacilli within the Mycobacterium tuberculosis complex (i.e., M. tuberculosis, M. bovis, M. africanum, M. pinnipedii, M. microti, M. caprae, or M. canetti). Mycobacterium bovis is the species most often isolated from tuberculous catt...

  2. Estimation of multipath transmission parameters for quantitative ultrasound measurements of bone.

    PubMed

    Dencks, Stefanie; Schmitz, Georg

    2013-09-01

    When applying quantitative ultrasound (QUS) measurements to bone for predicting osteoporotic fracture risk, the multipath transmission of sound waves frequently occurs. In the last 10 years, the interest in separating multipath QUS signals for their analysis awoke, and led to the introduction of several approaches. Here, we compare the performances of the two fastest algorithms proposed for QUS measurements of bone: the modified least-squares Prony method (MLSP), and the space alternating generalized expectation maximization algorithm (SAGE) applied in the frequency domain. In both approaches, the parameters of the transfer functions of the sound propagation paths are estimated. To provide an objective measure, we also analytically derive the Cramér-Rao lower bound of variances for any estimator and arbitrary transmit signals. In comparison with results of Monte Carlo simulations, this measure is used to evaluate both approaches regarding their accuracy and precision. Additionally, with simulations using typical QUS measurement settings, we illustrate the limitations of separating two superimposed waves for varying parameters with focus on their temporal separation. It is shown that for good SNRs around 100 dB, MLSP yields better results when two waves are very close. Additionally, the parameters of the smaller wave are more reliably estimated. If the SNR decreases, the parameter estimation with MLSP becomes biased and inefficient. Then, the robustness to noise of the SAGE clearly prevails. Because a clear influence of the interrelation between the wavelength of the ultrasound signals and their temporal separation is observable on the results, these findings can be transferred to QUS measurements at other sites. The choice of the suitable algorithm thus depends on the measurement conditions. PMID:24658719

  3. Estimating the Relative Role of Various Subcategories of Food, Water, and Animal Contact Transmission of 28 Enteric Diseases in Canada

    PubMed Central

    Butler, Ainslie J.; Thomas, M. Kate

    2016-01-01

    Abstract Objective: Enteric illness represents a significant burden of illness in Canada and internationally. Building on previous research, an expert elicitation was undertaken to explore the routes of transmission for 28 pathogens involved in enteric illness in Canada. This article considers the subcategories of foodborne, waterborne, and animal contact transmission. Methods: As part of an expert elicitation, 31 experts were asked to provide estimates of source attribution for subcategories of foodborne (n = 15), waterborne (n = 10), and animal contact (n = 3) transmission. The results from an online survey were combined using triangular probability distributions, and median and 90% credible intervals were produced. The total proportion and estimated number of cases of enteric illness attributable to each type of food commodity, water source, and animal exposure route were calculated using results from the larger elicitation survey and from a recent Canadian foodborne burden of illness study (Thomas et al., 2013). Results: Thirty experts provided foodborne subcategory estimates for 15/28 pathogens, waterborne subcategory estimates for 14/28 pathogens and animal contact subcategory estimates for 5/28. The elicitation identified raw produce, recreational water, and farm animal contact as important risk factors for enteric illness. These results also highlighted the complexity of transmission, with greater uncertainty for certain pathogens and routes of transmission. Conclusions: This study is the first of its kind to explore subcategories of foodborne, waterborne, and animal contact transmission across such a range of enteric pathogens. Despite inherent uncertainty, these estimates present an important quantitative synthesis of the roles of foodborne commodities, water sources, and pathways of animal contact in the transmission of enteric illness in Canada. PMID:26863428

  4. Outbreak of multi-drug-resistant tuberculosis in a New York State prison, 1991.

    PubMed

    Valway, S E; Richards, S B; Kovacovich, J; Greifinger, R B; Crawford, J T; Dooley, S W

    1994-07-15

    In the summer of 1991, four inmates from prison A in Upstate New York died of multi-drug-resistant tuberculosis. To determine the extent of resistant tuberculosis at prison A and transmission patterns, the authors interviewed staff and reviewed medical records and inmate movement histories. Contact investigation results were examined to determine tuberculin skin test conversions and to estimate risk of infection and disease for inmates who were seropositive for human immunodeficiency virus (HIV). Eight HIV-positive inmates and one HIV-negative guard, who was immunocompromised with cancer, had multi-drug-resistant tuberculosis. Eight died, a median of 28 days after the first culture-positive specimen was collected. All isolates had identical seven-drug resistance and DNA fingerprint patterns. Of exposed inmates, 92 out of 306 (30%) had skin test conversions. HIV infection was not associated with becoming infected with drug-resistant tuberculosis (active disease or skin test conversion), but once infected, HIV-positive inmates were significantly more likely to develop disease than were HIV-negative inmates (p < 0.001). The source case transferred to prison A in February 1991, was ill with undiagnosed multi-drug-resistant tuberculosis, refused medical care, and lived in the general prison population, where he transmitted the disease to other inmates. Lapses in infection control and laboratory delays contributed to this outbreak. Prisons should fully implement infection control guidelines to prevent tuberculosis transmission. PMID:8023800

  5. Transmission parameters estimated for Salmonella typhimurium in swine using susceptible-infectious-resistant models and a Bayesian approach

    PubMed Central

    2014-01-01

    Background Transmission models can aid understanding of disease dynamics and are useful in testing the efficiency of control measures. The aim of this study was to formulate an appropriate stochastic Susceptible-Infectious-Resistant/Carrier (SIR) model for Salmonella Typhimurium in pigs and thus estimate the transmission parameters between states. Results The transmission parameters were estimated using data from a longitudinal study of three Danish farrow-to-finish pig herds known to be infected. A Bayesian model framework was proposed, which comprised Binomial components for the transition from susceptible to infectious and from infectious to carrier; and a Poisson component for carrier to infectious. Cohort random effects were incorporated into these models to allow for unobserved cohort-specific variables as well as unobserved sources of transmission, thus enabling a more realistic estimation of the transmission parameters. In the case of the transition from susceptible to infectious, the cohort random effects were also time varying. The number of infectious pigs not detected by the parallel testing was treated as unknown, and the probability of non-detection was estimated using information about the sensitivity and specificity of the bacteriological and serological tests. The estimate of the transmission rate from susceptible to infectious was 0.33 [0.06, 1.52], from infectious to carrier was 0.18 [0.14, 0.23] and from carrier to infectious was 0.01 [0.0001, 0.04]. The estimate for the basic reproduction ration (R 0 ) was 1.91 [0.78, 5.24]. The probability of non-detection was estimated to be 0.18 [0.12, 0.25]. Conclusions The proposed framework for stochastic SIR models was successfully implemented to estimate transmission rate parameters for Salmonella Typhimurium in swine field data. R 0 was 1.91, implying that there was dissemination of the infection within pigs of the same cohort. There was significant temporal-cohort variability, especially at the

  6. [Tuberculosis and immigration].

    PubMed

    Salas-Coronas, Joaquín; Rogado-González, M Cruz; Lozano-Serrano, Ana Belén; Cabezas-Fernández, M Teresa

    2016-04-01

    The incidence of tuberculosis worldwide is declining. However, in Western countries this decline is slower due to the impact of immigration. Tuberculosis in the immigrant population is related to health status in the country of origin and with overcrowding and poverty conditions in the host country. Immigrants with tuberculosis are younger, have a higher prevalence of extrapulmonary forms, greater proportion of drug resistance and higher treatment default rates than those of natives. New molecular techniques not only reduce diagnostic delay time but also allow the rapid identification of resistances and improve knowledge of transmission patterns. It is necessary to implement measures to improve treatment compliance in this population group like facilitating access to health card, the use of fixed-dose combination drugs, the participation of cultural mediators and community health workers and gratuity of drugs. PMID:26851978

  7. Higher Rate of Tuberculosis in Second Generation Migrants Compared to Native Residents in a Metropolitan Setting in Western Europe

    PubMed Central

    Marx, Florian M.; Fiebig, Lena; Hauer, Barbara; Brodhun, Bonita; Glaser-Paschke, Gisela; Haas, Walter

    2015-01-01

    Background In Western Europe, migrants constitute an important risk group for tuberculosis, but little is known about successive generations of migrants. We aimed to characterize migration among tuberculosis cases in Berlin and to estimate annual rates of tuberculosis in two subsequent migrant generations. We hypothesized that second generation migrants born in Germany are at higher risk of tuberculosis compared to native (non-migrant) residents. Methods A prospective cross-sectional study was conducted. All tuberculosis cases reported to health authorities in Berlin between 11/2010 and 10/2011 were eligible. Interviews were conducted using a structured questionnaire including demographic data, migration history of patients and their parents, and language use. Tuberculosis rates were estimated using 2011 census data. Results Of 314 tuberculosis cases reported, 154 (49.0%) participated. Of these, 81 (52.6%) were first-, 14 (9.1%) were second generation migrants, and 59 (38.3%) were native residents. The tuberculosis rate per 100,000 individuals was 28.3 (95CI: 24.0–32.6) in first-, 10.2 (95%CI: 6.1–16.6) in second generation migrants, and 4.6 (95%CI: 3.7–5.6) in native residents. When combining information from the standard notification variables country of birth and citizenship, the sensitivity to detect second generation migration was 28.6%. Conclusions There is a higher rate of tuberculosis among second generation migrants compared to native residents in Berlin. This may be explained by presumably frequent contact and transmission within migrant populations. Second generation migration is insufficiently captured by the surveillance variables country of birth and citizenship. Surveillance systems in Western Europe should allow for quantifying the tuberculosis burden in this important risk group. PMID:26061733

  8. Estimation of the dynamics and rate of transmission of classical swine fever (hog cholera) in wild pigs.

    PubMed Central

    Hone, J.; Pech, R.; Yip, P.

    1992-01-01

    Infectious diseases establish in a population of wildlife hosts when the number of secondary infections is greater than or equal to one. To estimate whether establishment will occur requires extensive experience or a mathematical model of disease dynamics and estimates of the parameters of the disease model. The latter approach is explored here. Methods for estimating key model parameters, the transmission coefficient (beta) and the basic reproductive rate (RDRS), are described using classical swine fever (hog cholera) in wild pigs as an example. The tentative results indicate that an acute infection of classical swine fever will establish in a small population of wild pigs. Data required for estimation of disease transmission rates are reviewed and sources of bias and alternative methods discussed. A comprehensive evaluation of the biases and efficiencies of the methods is needed. PMID:1582476

  9. Capacity estimates for optical transmission based on the nonlinear Fourier transform.

    PubMed

    Derevyanko, Stanislav A; Prilepsky, Jaroslaw E; Turitsyn, Sergei K

    2016-01-01

    What is the maximum rate at which information can be transmitted error-free in fibre-optic communication systems? For linear channels, this was established in classic works of Nyquist and Shannon. However, despite the immense practical importance of fibre-optic communications providing for >99% of global data traffic, the channel capacity of optical links remains unknown due to the complexity introduced by fibre nonlinearity. Recently, there has been a flurry of studies examining an expected cap that nonlinearity puts on the information-carrying capacity of fibre-optic systems. Mastering the nonlinear channels requires paradigm shift from current modulation, coding and transmission techniques originally developed for linear communication systems. Here we demonstrate that using the integrability of the master model and the nonlinear Fourier transform, the lower bound on the capacity per symbol can be estimated as 10.7 bits per symbol with 500 GHz bandwidth over 2,000 km. PMID:27611059

  10. Short term estimates of adult HIV incidence by mode of transmission: Kenya and Thailand as examples

    PubMed Central

    Gouws, E; White, P J; Stover, J; Brown, T

    2006-01-01

    Objective Patterns of transmission of HIV are different among different regions of the world and change over time within regions. In order to adapt prevention strategies to changing patterns of risk, we need to understand the behaviours that put people at risk of infection and how new infections are distributed among risk groups. Methods A model is described to calculate the expected incidence of HIV infections in the adult population by mode of exposure using the current distribution of prevalent infections and the patterns of risk within different populations. For illustration the model is applied to Thailand and Kenya. Results New infections in Kenya were mainly transmitted through heterosexual contact (90%), while a small but significant number were related to injecting drug use (4.8%) and men who have sex with men (4.5%). In Thailand, the epidemic has spread over time to the sexual partners of vulnerable groups and in 2005 the majority of new infections occurred among the low risk heterosexual population (43%). Men having sex with men accounted for 21% and sex work (including sex workers, clients, and partners of clients) for 18% of new infections. Medical interventions did not contribute significantly to new infections in either Kenya or Thailand. Conclusions The model provides a simple tool to inform the planning of effective, appropriately targeted, country specific intervention programmes. However, better surveillance systems are needed in countries to obtain more reliable biological and behavioural data in order to improve the estimates of incidence by risk group. PMID:16735294

  11. Incorporating a Time Horizon in Rate-of-Return Estimations: Discounted Cash Flow Model in Electric Transmission Rate Cases

    SciTech Connect

    Chatterjee, Bishu; Sharp, Peter A.

    2006-07-15

    Electric transmission and other rate cases use a form of the discounted cash flow model with a single long-term growth rate to estimate rates of return on equity. It cannot incorporate information about the appropriate time horizon for which analysts' estimates of earnings growth have predictive powers. Only a non-constant growth model can explicitly recognize the importance of the time horizon in an ROE calculation. (author)

  12. Mycobacterium tuberculosis Genotypes Determined by Spoligotyping to Be Circulating in Colombia between 1999 and 2012 and Their Possible Associations with Transmission and Susceptibility to First-Line Drugs

    PubMed Central

    Puerto, Gloria; Erazo, Lina; Wintaco, Maira; Castro, Claudia; Ribón, Wellman; Guerrero, Martha Inírida

    2015-01-01

    Introduction Tuberculosis (TB) remains a primary public health problem worldwide. The number of multidrug-resistant tuberculosis (MDR TB) cases has increased in recent years in Colombia. Knowledge of M. tuberculosis genotypes defined by spoligotyping can help determine the circulation of genotypes that must be controlled to prevent the spread of TB. Objective To describe the genotypes of M. tuberculosis using spoligotyping in resistant and drug-sensitive isolates and their possible associations with susceptibility to first-line drugs. Methods An analytical observational study was conducted that included 741 isolates of M. tuberculosis from patients. The isolates originated from 31 departments and were obtained by systematic surveillance between 1999 and 2012. Results In total 61.94% of the isolates were resistant to 1 or more drugs, and 147 isolates were MDR. In total, 170 genotypes were found in the population structure of Colombian M. tuberculosis isolates. The isolates were mainly represented by four families: LAM (39.9%), Haarlem (19%), Orphan (17%) and T (9%). The SIT42 (LAM 9) was the most common genotype and contained 24.7% of the isolates, followed by the genotypes SIT62 (Haarlem1), SIT53 (T1), and SIT50 (H3). A high clustering of isolates was evident with 79.8% of the isolates classified into 32 groups. The Beijing family was associated with resistant isolates, whereas the Haarlem and T families were associated with sensitive isolates. The Haarlem family was also associated with grouped isolates (p = 0.031). Conclusions A high proportion (approximately 80%) of isolates was found in clusters; these clusters were not associated with resistance to first-line drugs. The Beijing family was associated with drug resistance, whereas the T and Haarlem families were associated with susceptibility in the Colombian isolates studied. PMID:26066494

  13. Estimates of Outbreak Risk from New Introductions of Ebola with Immediate and Delayed Transmission Control

    PubMed Central

    Gundlapalli, Adi V.; Khader, Karim; Pettey, Warren B.P.; Rubin, Michael A.; Adler, Frederick R.; Samore, Matthew H.

    2015-01-01

    While the ongoing Ebola outbreak continues in the West Africa countries of Guinea, Sierra Leone, and Liberia, health officials elsewhere prepare for new introductions of Ebola from infected evacuees or travelers. We analyzed transmission data from patients (i.e., evacuees, international travelers, and those with locally acquired illness) in countries other than the 3 with continuing Ebola epidemics and quantitatively assessed the outbreak risk from new introductions by using different assumptions for transmission control (i.e., immediate and delayed). Results showed that, even in countries that can quickly limit expected number of transmissions per case to <1, the probability that a single introduction will lead to a substantial number of transmissions is not negligible, particularly if transmission variability is high. Identifying incoming infected travelers before symptom onset can decrease worst-case outbreak sizes more than reducing transmissions from patients with locally acquired cases, but performing both actions can have a synergistic effect. PMID:26196264

  14. Tuberculosis control and economic recession: longitudinal study of data from 21 European countries, 1991–2012

    PubMed Central

    Reeves, Aaron; Basu, Sanjay; McKee, Martin; Sandgren, Andreas; Semenza, Jan C

    2015-01-01

    Abstract Objective To investigate whether the economic recession affected the control of tuberculosis in the European Union. Methods Multivariate regression models were used to quantify the association between gross domestic product, public health expenditure and tuberculosis case detection rates, using data from 21 European Union member states (1991–2012). The estimated changes in case detection attributable to the recession were combined with mathematical models of tuberculosis transmission, to project the potential influence of the recession on tuberculosis epidemiology until 2030. Findings Between 1991 and 2007, detection rates for sputum-smear-positive tuberculosis in the European Union were stable at approximately 85%. During the economic recession (2008–2011) detection rates declined by a mean of 5.22% (95% confidence interval, CI: 2.54–7.90) but treatment success rates showed no significant change (P = 0.62). A fall in economic output of 100 United States dollars per capita was associated with a 0.22% (95% CI: 0.05–0.39) mean reduction in the tuberculosis case detection rate. An equivalent fall in spending on public health services was associated with a 2.74% (95% CI: 0.31–5.16) mean reduction in the detection rate. Mathematical models suggest that the recession and consequent austerity policies will lead to increases in tuberculosis prevalence and tuberculosis-attributable mortality that are projected to persist for over a decade. Conclusion Across the European Union, reductions in spending on public health services appear to have reduced tuberculosis case detection and to have increased the long-term risk of a resurgence in the disease. PMID:26240458

  15. Burden of tuberculosis in Kampala, Uganda.

    PubMed Central

    Guwatudde, David; Zalwango, Sarah; Kamya, Moses R.; Debanne, Sara M.; Diaz, Mireya I.; Okwera, Alphonse; Mugerwa, Roy D.; King, Charles; Whalen, Christopher C.

    2003-01-01

    OBJECTIVE: To determine the prevalence and incidence of tuberculosis in one of Uganda's poor peri-urban areas. METHODS: Multi-stage sampling was used to select a sample of households whose members were evaluated for presence of signs and/or symptoms of active tuberculosis; history of tuberculosis treatment; and relevant demographic, socioeconomic, and household environment characteristics. Patients with suspected tuberculosis underwent standardized evaluation for active disease. FINDINGS: A sample of 263 households with 1142 individuals was evaluated. Nineteen people were classified as having had tuberculosis during the one-year reference period (May 2001-April 2002): nine (47%) cases already had been diagnosed through the health care system, while 10 cases (53%) were diagnosed through the survey. The prevalences for all forms of tuberculosis and for sputum smear-positive tuberculosis were 14.0 (95% confidence interval (CI) 7.8-20.3) and 4.4 (CI = 0.83-7.89) per thousand, respectively. The incidences for all forms of tuberculosis and for sputum smear-positive tuberculosis were 9.2 (CI = 3.97-14.4) and 3.7 (CI = 0.39-6.95) per thousand per year, respectively. CONCLUSION: The rate of tuberculosis in this peri-urban community was exceptionally high and may be underestimated by current surveillance systems. The need for interventions aimed at reducing tuberculosis transmission in this, and other similar communities with high case rates, is urgent. PMID:14758406

  16. Molecular Epidemiology of Tuberculosis: Current Insights

    PubMed Central

    Mathema, Barun; Kurepina, Natalia E.; Bifani, Pablo J.; Kreiswirth, Barry N.

    2006-01-01

    Molecular epidemiologic studies of tuberculosis (TB) have focused largely on utilizing molecular techniques to address short- and long-term epidemiologic questions, such as in outbreak investigations and in assessing the global dissemination of strains, respectively. This is done primarily by examining the extent of genetic diversity of clinical strains of Mycobacterium tuberculosis. When molecular methods are used in conjunction with classical epidemiology, their utility for TB control has been realized. For instance, molecular epidemiologic studies have added much-needed accuracy and precision in describing transmission dynamics, and they have facilitated investigation of previously unresolved issues, such as estimates of recent-versus-reactive disease and the extent of exogenous reinfection. In addition, there is mounting evidence to suggest that specific strains of M. tuberculosis belonging to discrete phylogenetic clusters (lineages) may differ in virulence, pathogenesis, and epidemiologic characteristics, all of which may significantly impact TB control and vaccine development strategies. Here, we review the current methods, concepts, and applications of molecular approaches used to better understand the epidemiology of TB. PMID:17041139

  17. Analysis of well hydrographs in a karst aquifer: Estimates of specific yields and continuum transmissivities

    SciTech Connect

    Shevenell, L.A.

    1994-11-01

    Hydrograph analysis techniques have been well developed for hydrographs obtained from streams and springs, where data are cast in terms of total discharge. The data obtained from well hydrographs provide water level versus time; hence, a method of hydrograph analysis is required for situations in which only water level data are available. It is hypothesized here that three segments on a recession curve from wells in a karst aquifer represent drainage from three types of storage: conduit (C), fracture (F), and matrix (M). Hydrographs from several wells in a karst aquifer at the U.S. Department of Energy Oak Ridge Y-12 Plant are used to estimate the specific yields (S{sub y}) associated with each portion of the aquifer (C, F, M), as well as continuum transmissivities (T). Data from three short injection tests at one well indicate continuum T at this well bore is {approximately} 5m{sup 2}/d, and tests at numerous other wells in the aquifer yield results between 1 and 7 M{sup 2}/d. The T estimated with well hydrographs from two storm events indicates a T of 9.8 m{sup 2}2/d. Well developed conduit systems in which water levels in wells show a flashy response typically show S{sub y} values of 1{times}10{sup -4}, 1{times}10{sup -3}, and 3{times}10{sup -3}, for C, F, and M. Less well developed conduit areas show more nearly equal S{sub y} values (8.6{times}10{sup -4}, 1.3{times}10{sup -3}, 3{times}10{sup -3}). Areas with no evidence for the presence of conduits have only one, or in some cases two, slopes on the recession curve. In these cases, water level responses are slow. Recession curves with a single slope represent drainage from only the lower T matrix. Those with two slopes have an additional, more rapid response, segment on the recession curve, which represents drainage from the higher T, lower S{sub y}, fractures in the system.

  18. Pancreatic Tuberculosis.

    PubMed

    Chaudhary, Poras; Bhadana, Utsav; Arora, Mohinder P

    2015-12-01

    Tuberculosis of the pancreas is extremely rare and in most of the cases mimics pancreatic carcinoma. There are a number of case reports on pancreatic tuberculosis with various different presentations, but only a few case series have been published, and most of our knowledge about this disease comes from individual case reports. Patients of pancreatic tuberculosis may remain asymptomatic initially and manifest as an abscess or a mass involving local lymph nodes and usually present with non-specific features. Pancreatic tuberculosis may present with a wide range of imaging findings. It is difficult to diagnose tuberculosis of pancreas on imaging studies as they may present with masses, cystic lesions or abscesses and mass lesions in most of the cases mimic pancreatic carcinoma. As it is a rare entity, it cannot be recommended but suggested that pancreatic tuberculosis should be considered in cases with a large space occupying lesions associated with necrotic peripancreatic lymph nodes and constitutional symptoms. Ultrasonography/computed tomography/endosonography-guided biopsy is the recommended diagnostic technique. Most patients achieve complete cure with standard antituberculous therapy. The aims of this study are to review clinical presentation, diagnostic studies, and management of pancreatic tuberculosis and to present our experience of 5 cases of pancreatic tuberculosis. PMID:26884661

  19. Limitations to estimating bacterial cross-species transmission using genetic and genomic markers: inferences from simulation modeling

    PubMed Central

    Benavides, Julio A; Cross, Paul C; Luikart, Gordon; Creel, Scott

    2014-01-01

    Cross-species transmission (CST) of bacterial pathogens has major implications for human health, livestock, and wildlife management because it determines whether control actions in one species may have subsequent effects on other potential host species. The study of bacterial transmission has benefitted from methods measuring two types of genetic variation: variable number of tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). However, it is unclear whether these data can distinguish between different epidemiological scenarios. We used a simulation model with two host species and known transmission rates (within and between species) to evaluate the utility of these markers for inferring CST. We found that CST estimates are biased for a wide range of parameters when based on VNTRs and a most parsimonious reconstructed phylogeny. However, estimations of CST rates lower than 5% can be achieved with relatively low bias using as low as 250 SNPs. CST estimates are sensitive to several parameters, including the number of mutations accumulated since introduction, stochasticity, the genetic difference of strains introduced, and the sampling effort. Our results suggest that, even with whole-genome sequences, unbiased estimates of CST will be difficult when sampling is limited, mutation rates are low, or for pathogens that were recently introduced. PMID:25469159

  20. Contribution of Company Affiliation and Social Contacts to Risk Estimates of Between-Farm Transmission of Avian Influenza

    PubMed Central

    Leibler, Jessica H.; Carone, Marco; Silbergeld, Ellen K.

    2010-01-01

    Background Models of between-farm transmission of pathogens have identified service vehicles and social groups as risk factors mediating the spread of infection. Because of high levels of economic organization in much of the poultry industry, we examined the importance of company affiliation, as distinct from social contacts, in a model of the potential spread of avian influenza among broiler poultry farms in a poultry-dense region in the United States. The contribution of company affiliation to risk of between-farm disease transmission has not been previously studied. Methodology/Principal Findings We obtained data on the nature and frequency of business and social contacts through a national survey of broiler poultry growers in the United States. Daily rates of contact were estimated using Monte Carlo analysis. Stochastic modeling techniques were used to estimate the exposure risk posed by a single infectious farm to other farms in the region and relative risk of exposure for farms under different scenarios. The mean daily rate of vehicular contact was 0.82 vehicles/day. The magnitude of exposure risk ranged from <1% to 25% under varying parameters. Risk of between-farm transmission was largely driven by company affiliation, with farms in the same company group as the index farm facing as much as a 5-fold increase in risk compared to farms contracted with different companies. Employment of part-time workers contributed to significant increases in risk in most scenarios, notably for farms who hired day-laborers. Social visits were significantly less important in determining risk. Conclusions/Significance Biosecurity interventions should be based on information on industry structure and company affiliation, and include part-time workers as potentially unrecognized sources of viral transmission. Modeling efforts to understand pathogen transmission in the context of industrial food animal production should consider company affiliation in addition to geospatial

  1. Tuberculosis (TB): Treatment

    MedlinePlus

    ... Departments & Divisions Home Conditions Tuberculosis Treating Tuberculosis Treating Tuberculosis Make an Appointment Refer a Patient Ask a ... bones is treated longer. NEXT: Preventive Treatment Diagnosing Tuberculosis History of TB Our Specialists Charles L. Daley, ...

  2. Estimating transmissivity in the Edwards Aquifer using upscaling, geostatistics, and Bayesian updating

    NASA Astrophysics Data System (ADS)

    Painter, S. L.; Jiang, Y.; Woodbury, A. D.

    2002-12-01

    The Edwards Aquifer, a highly heterogeneous karst aquifer located in south central Texas, is the sole source of drinking water for more than one million people. Hydraulic conductivity (K) measurements in the Edwards Aquifer are sparse, highly variable (log-K variance of 6.4), and are mostly from single-well drawdown tests that are appropriate for the spatial scale of a few meters. To support ongoing efforts to develop a groundwater management (MODFLOW) model of the San Antonio segment of the Edwards Aquifer, a multistep procedure was developed to assign hydraulic parameters to the 402 m x 402 m computational cells intended for the management model. The approach used a combination of nonparametric geostatistical analysis, stochastic simulation, numerical upscaling, and automatic model calibration based on Bayesian updating [1,2]. Indicator correlograms reveal a nested spatial structure in the well-test K of the confined zone, with practical correlation ranges of 3,600 and 15,000 meters and a large nugget effect. The fitted geostatistical model was used in unconditional stochastic simulations by the sequential indicator simulation method. The resulting realizations of K, defined at the scale of the well tests, were then numerically upscaled to the block scale. A new geostatistical model was fitted to the upscaled values. The upscaled model was then used to cokrige the block-scale K based on the well-test K. The resulting K map was then converted to transmissivity (T) using deterministically mapped aquifer thickness. When tested in a forward groundwater model, the upscaled T reproduced hydraulic heads better than a simple kriging of the well-test values (mean error of -3.9 meter and mean-absolute-error of 12 meters, as compared with -13 and 17 meters for the simple kriging). As the final step in the study, the upscaled T map was used as the prior distribution in an inverse procedure based on Bayesian updating [1,2]. When input to the forward groundwater model, the

  3. Estimation of Parameters Influencing Waterborne Transmission of Infectious Hematopoietic Necrosis Virus (IHNV) in Atlantic Salmon (Salmo salar)

    PubMed Central

    Garver, Kyle A; Mahony, Amelia A. M.; Stucchi, Dario; Richard, Jon; Van Woensel, Cecile; Foreman, Mike

    2013-01-01

    Understanding how pathogenic organisms spread in the environment is crucial for the management of disease, yet knowledge of propagule dispersal and transmission in aquatic environments is limited. We conducted empirical studies using the aquatic virus, infectious hematopoietic necrosis virus (IHNV), to quantify infectious dose, shedding capacity, and virus destruction rates in order to better understand the transmission of IHN virus among Atlantic salmon marine net-pen aquaculture. Transmission of virus and subsequent mortality in Atlantic salmon post-smolts was initiated with as low as 10 plaque forming units (pfu) ml−1. Virus shedding from IHNV infected Atlantic salmon was detected before the onset of visible signs of disease with peak shed rates averaging 3.2×107 pfu fish−1 hour−1 one to two days prior to mortality. Once shed into the marine environment, the abundance of free IHNV is modulated by sunlight (UV A and B) and the growth of natural biota present in the seawater. Virus decayed very slowly in sterilized seawater while rates as high as k =  4.37 d−1 were observed in natural seawater. Decay rates were further accelerated when exposed to sunlight with virus infectivity reduced by six orders of magnitude within 3 hours of full sunlight exposure. Coupling the IHNV transmission parameter estimates determined here with physical water circulation models, will increase the understanding of IHNV dispersal and provide accurate geospatial predictions of risk for IHNV transmission from marine salmon sites. PMID:24340016

  4. Estimation of Recent and Long-Term Malaria Transmission in a Population by Antibody Testing to Multiple Plasmodium falciparum Antigens

    PubMed Central

    Ondigo, Bartholomew N.; Hodges, James S.; Ireland, Kathleen F.; Magak, Ng'wena G.; Lanar, David E.; Dutta, Sheetij; Narum, David L.; Park, Gregory S.; Ofulla, Ayub V.; John, Chandy C.

    2014-01-01

    Background. Tools that estimate recent and long-term malaria transmission in a population would be highly useful for malaria elimination programs. Methods. The prevalence of antibodies to 11 Plasmodium falciparum antigens was assessed by cytometric bead assay or enzyme-linked immunosorbent assay in 1000 people in a highland area of Kenya over 14 months, during a period of interrupted malaria transmission. Results. Antibodies differed by antigen in acquisition with age: rapid (>80% antibody positive by age 20 years, 5 antigens), moderate (>40% positive by age 20 years, 3 antigens), or slow (<40% positive by age 20 years, 3 antigens). Antibody seroreversion rates in the 14 months between samples decreased with age rapidly (7 antigens), slowly (3 antigens), or remained high at all ages (schizont extract). Estimated antibody half-lives in individuals >10 years of age were long (40 to >80 years) for 5 antigens, moderate (5–20 years) for 3 antigens, and short (<1 year) for 3 antigens. Conclusions. Antibodies to P. falciparum antigens in malaria-endemic areas vary by age, antigen, and time since last exposure to P. falciparum. Multiplex P. falciparum antibody testing could provide estimates of long-term and recent malaria transmission and potentially of a population's susceptibility to future clinical malaria. PMID:24737801

  5. Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards

    USGS Publications Warehouse

    Cross, Paul C.; Maichak, Eric J.; Rogerson, Jared D.; Irvine, Kathryn M.; Jones, Jennifer D; Heisey, Dennis M.; Edwards, William H.; Scurlock, Brandon M.

    2015-01-01

    Understanding the seasonal timing of disease transmission can lead to more effective control strategies, but the seasonality of transmission is often unknown for pathogens transmitted directly. We inserted vaginal implant transmitters (VITs) in 575 elk (Cervus elaphus canadensis) from 2006 to 2014 to assess when reproductive failures (i.e., abortions or still births) occur, which is the primary transmission route of Brucella abortus, the causative agent of brucellosis in the Greater Yellowstone Ecosystem. Using a survival analysis framework, we developed a Bayesian hierarchical model that simultaneously estimated the total baseline hazard of a reproductive event as well as its 2 mutually exclusive parts (abortions or live births). Approximately, 16% (95% CI = 0.10, 0.23) of the pregnant seropositive elk had reproductive failures, whereas 2% (95% CI = 0.01, 0.04) of the seronegative elk had probable abortions. Reproductive failures could have occurred as early as 13 February and as late as 10 July, peaking from March through May. Model results suggest that less than 5% of likely abortions occurred after 6 June each year and abortions were approximately 5 times more likely in March, April, or May compared to February or June. In western Wyoming, supplemental feeding of elk begins in December and ends during the peak of elk abortions and brucellosis transmission (i.e., Mar and Apr). Years with more snow may enhance elk-to-elk transmission on supplemental feeding areas because elk are artificially aggregated for the majority of the transmission season. Elk-to-cattle transmission will depend on the transmission period relative to the end of the supplemental feeding season, elk seroprevalence, population size, and the amount of commingling. Our statistical approach allowed us to estimate the probability density function of different event types over time, which may be applicable to other cause-specific survival analyses. It is often challenging to assess the

  6. Numerical evaluation of volumetric weighted mean transmissivity estimates in laterally heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Rhode, Katherine L.; Osiensky, James L.; Miller, Stanley M.

    2007-12-01

    SummaryMost previous investigations to evaluate the "effective" or average transmissivity in heterogeneous environments have used calculations based on areas to weight the effects of each heterogeneity. Analysis of spatial volumetric variations within the cone of depression expressed at the potentiometric surface offers a more general solution to evaluate the meaning of transmissivity ( T) and storativity ( S) values derived from aquifer tests in these environments. The [Cooper Jr., H.H., Jacob, C.E. 1946. A generalized graphical method for evaluating formation constants and summarizing well-field history. Eos Trans. AGU, 27(4), 526-534] method is used to demonstrate that T variations reflected in slope changes in plots of the pumping well drawdown data correspond to changes in the volumetric weighted mean transmissivity ( VWMT) over time. Lognormal distributions of transmissivity are represented by block heterogeneities within two simulated aquifers, for both spatially random and spatially correlated data sets. By analyzing the volumetric evolution of the cone of depression observed in the potentiometric surface, the nature of T averaging within the cone of depression as a function of time is illustrated. Volumetric analysis shows that the average aquifer T varies with time as the cone of depression progressively envelops different heterogeneities. The initial trend is controlled primarily by the heterogeneities directly surrounding the pumping center. If steady-shape conditions are not achieved, late-time VWMT values do not approach an asymptotic limit.

  7. [Extrapulmonary tuberculosis].

    PubMed

    Ketata, W; Rekik, W K; Ayadi, H; Kammoun, S

    2015-01-01

    Each year, there are more than eight million new cases of tuberculosis and 1.3 million deaths. There is a renewed interest in extrapulmonary forms of tuberculosis as its relative frequency increases. Among extrapulmonary organs, pleura and lymph nodes are the most common. Their diagnosis is often difficult and is based on clinical, radiological, bacteriological and histological findings. Extrapulmonary lesions are paucibacillary and samplings, in most cases, difficult to obtain, so diagnosis is often simply presumptive. Nucleic acid amplification tests, which are fast and specific, have greatly facilitated the diagnosis of some forms of extrapulmonary tuberculosis. However, their sensitivity is poor and a negative test does not eliminate the diagnosis. Treatment is the same as for pulmonary forms, but its duration is nine to 12 months for central nervous system and for bone tuberculosis. Corticosteroids are indicated in meningeal and pericardial localizations. Complementary surgery is used for certain complicated forms. PMID:25131362

  8. Transmission-less attenuation estimation from time-of-flight PET histo-images using consistency equations

    NASA Astrophysics Data System (ADS)

    Li, Yusheng; Defrise, Michel; Metzler, Scott D.; Matej, Samuel

    2015-08-01

    In positron emission tomography (PET) imaging, attenuation correction with accurate attenuation estimation is crucial for quantitative patient studies. Recent research showed that the attenuation sinogram can be determined up to a scaling constant utilizing the time-of-flight information. The TOF-PET data can be naturally and efficiently stored in a histo-image without information loss, and the radioactive tracer distribution can be efficiently reconstructed using the DIRECT approaches. In this paper, we explore transmission-less attenuation estimation from TOF-PET histo-images. We first present the TOF-PET histo-image formation and the consistency equations in the histo-image parameterization, then we derive a least-squares solution for estimating the directional derivatives of the attenuation factors from the measured emission histo-images. Finally, we present a fast solver to estimate the attenuation factors from their directional derivatives using the discrete sine transform and fast Fourier transform while considering the boundary conditions. We find that the attenuation histo-images can be uniquely determined from the TOF-PET histo-images by considering boundary conditions. Since the estimate of the attenuation directional derivatives can be inaccurate for LORs tangent to the patient boundary, external sources, e.g. a ring or annulus source, might be needed to give an accurate estimate of the attenuation gradient for such LORs. The attenuation estimation from TOF-PET emission histo-images is demonstrated using simulated 2D TOF-PET data.

  9. Focusing the HIV response through estimating the major modes of HIV transmission: a multi-country analysis

    PubMed Central

    Gouws, Eleanor; Cuchi, Paloma

    2012-01-01

    Objective An increasing number of countries have been estimating the distribution of new adult HIV infections by modes of transmission (MOT) to help prioritise prevention efforts. We compare results from studies conducted between 2008 and 2012 and discuss their use for planning and responding to the HIV epidemic. Methods The UNAIDS recommended MOT model helps countries to estimate the proportion of new HIV infections that occur through key transmission modes including sex work, injecting drug use (IDU), men having sex with men (MSM), multiple sexual partnerships, stable relationships and medical interventions. The model typically forms part of a country-led process that includes a comprehensive review of epidemiological data. Recent revisions to the model are described. Results Modelling results from 25 countries show large variation between and within regions. In sub-Saharan Africa, new infections occur largely in the general heterosexual population because of multiple partnerships or in stable discordant relationships, while sex work contributes significantly to new infections in West Africa. IDU and sex work are the main contributors to new infections in the Middle East and North Africa, with MSM the main contributor in Latin America. Patterns vary substantially between countries in Eastern Europe and Asia in terms of the relative contribution of sex work, MSM, IDU and spousal transmission. Conclusions The MOT modelling results, comprehensive review and critical assessment of data in a country can contribute to a more strategically focused HIV response. To strengthen this type of research, improved epidemiological and behavioural data by risk population are needed. PMID:23172348

  10. Diabetes and tuberculosis: the impact of the diabetes epidemic on tuberculosis incidence

    PubMed Central

    Stevenson, Catherine R; Forouhi, Nita G; Roglic, Gojka; Williams, Brian G; Lauer, Jeremy A; Dye, Chirstopher; Unwin, Nigel

    2007-01-01

    Background Tuberculosis (TB) remains a major cause of mortality in developing countries, and in these countries diabetes prevalence is increasing rapidly. Diabetes increases the risk of TB. Our aim was to assess the potential impact of diabetes as a risk factor for incident pulmonary tuberculosis, using India as an example. Methods We constructed an epidemiological model using data on tuberculosis incidence, diabetes prevalence, population structure, and relative risk of tuberculosis associated with diabetes. We evaluated the contribution made by diabetes to both tuberculosis incidence, and to the difference between tuberculosis incidence in urban and rural areas. Results In India in 2000 there were an estimated 20.7 million adults with diabetes, and 900,000 incident adult cases of pulmonary tuberculosis. Our calculations suggest that diabetes accounts for 14.8% (uncertainty range 7.1% to 23.8%) of pulmonary tuberculosis and 20.2% (8.3% to 41.9%) of smear-positive (i.e. infectious) tuberculosis. We estimate that the increased diabetes prevalence in urban areas is associated with a 15.2% greater smear-positive tuberculosis incidence in urban than rural areas – over a fifth of the estimated total difference. Conclusion Diabetes makes a substantial contribution to the burden of incident tuberculosis in India, and the association is particularly strong for the infectious form of tuberculosis. The current diabetes epidemic may lead to a resurgence of tuberculosis in endemic regions, especially in urban areas. This potentially carries a risk of global spread with serious implications for tuberculosis control and the achievement of the United Nations Millennium Development Goals. PMID:17822539

  11. Groundwater modelling: Towards an estimation of the acceleration factors of iterative methods via an analysis of the transmissivity spatial variability

    NASA Astrophysics Data System (ADS)

    Benali, Abdelmajid

    2013-01-01

    When running a groundwater flow model, a recurrent and seemingly subsidiary question arises at the starting step of computations: what value of acceleration parameter do we need to optimize the numerical solver? A method is proposed to provide a practical estimate of the optimal acceleration parameter via a geostatistical analysis of the spatial variability of the logarithm of the transmissivity field Y. The background of the approach is illustrated on the successive over-relaxation method (SOR) used, either as a stand-alone solver, or as a symmetric preconditioner (SSOR) to the gradient conjugate method, or as a smoother in multigrid methods. It shows that this optimum acceleration factor is a function of the standard deviation and the correlation length of Y. This provides an easy-to-use heuristic procedure to estimate the acceleration factors, which could even be incorporated in the software package. A case study illustrates the steps needed to perform this estimation.

  12. Tuberculosis outbreak in a Texas prison, 1994.

    PubMed

    Bergmire-Sweat, D; Barnett, B J; Harris, S L; Taylor, J P; Mazurek, G H; Reddy, V

    1996-12-01

    In 1994 a Texas prison containing a population of mentally retarded inmates experienced a large tuberculosis outbreak. Fifteen cases of tuberculosis were identified (8 confirmed by positive cultures for Mycobacterium tuberculosis) and more than 100 inmates became infected. The culture-confirmed patients were infected with an identical strain of tuberculosis as demonstrated by polymerase chain reaction (PCR) based DNA fingerprinting technique. The prison followed standard tuberculosis infection control policies, but these controls were inadequate to prevent tuberculosis transmission in this special population. Two hundred and thirty inmates (119 inmates showing evidence of new tuberculosis infection or active disease and 111 healthy controls) were enrolled in the investigation. Inmate cell assignments, job duties, and educational classes were identified and medical chart reviews were conducted on all inmates. Tuberculosis transmission was associated with residing on the D Wing of the prison (OR = 25.84, P < 0.01), attending school in Classroom A (OR = 8.34, P = 0.01) and working on the prison utility work crew (OR = 2.52, P < 0.01). The index case in the outbreak had been prescribed 6 months of isoniazid (INH) chemoprophylaxis in 1988. PMID:8972673

  13. Q parameter estimation using numerical simulations for linear and nonlinear transmission systems

    NASA Astrophysics Data System (ADS)

    Eberhard, Marc; Blow, Keith J.

    2006-09-01

    We compare the Q parameter obtained from scalar, semi-analytical and full vector models for realistic transmission systems. One set of systems is operated in the linear regime, while another is using solitons at high peak power. We report in detail on the different results obtained for the same system using different models. Polarisation mode dispersion is also taken into account and a novel method to average Q parameters over several independent simulation runs is described.

  14. Model-Based Estimates of the Effects of Efavirenz on Bedaquiline Pharmacokinetics and Suggested Dose Adjustments for Patients Coinfected with HIV and Tuberculosis

    PubMed Central

    Svensson, Elin M.; Aweeka, Francesca; Park, Jeong-Gun; Marzan, Florence; Karlsson, Mats O.

    2013-01-01

    Safe, effective concomitant treatment regimens for tuberculosis (TB) and HIV infection are urgently needed. Bedaquiline (BDQ) is a promising new anti-TB drug, and efavirenz (EFV) is a commonly used antiretroviral. Due to EFV's induction of cytochrome P450 3A4, the metabolic enzyme responsible for BDQ biotransformation, the drugs are expected to interact. Based on data from a phase I, single-dose pharmacokinetic study, a nonlinear mixed-effects model characterizing BDQ pharmacokinetics and interaction with multiple-dose EFV was developed. BDQ pharmacokinetics were best described by a 3-compartment disposition model with absorption through a dynamic transit compartment model. Metabolites M2 and M3 were described by 2-compartment models with clearance of BDQ and M2, respectively, as input. Impact of induction was described as an instantaneous change in clearance 1 week after initialization of EFV treatment and estimated for all compounds. The model predicts average steady-state concentrations of BDQ and M2 to be reduced by 52% (relative standard error [RSE], 3.7%) with chronic coadministration. A range of models with alternative structural assumptions regarding onset of induction effect and fraction metabolized resulted in similar estimates of the typical reduction and did not offer a markedly better fit to data. Simulations to investigate alternative regimens mitigating the estimated interaction effect were performed. The results suggest that simple adjustments of the standard regimen during EFV coadministration can prevent reduced exposure to BDQ without increasing exposures to M2. However, exposure to M3 would increase. Evaluation in clinical trials of adjusted regimens is necessary to ensure appropriate dosing for HIV-infected TB patients on an EFV-based regimen. PMID:23571542

  15. Facing multi-drug resistant tuberculosis.

    PubMed

    Sotgiu, Giovanni; Migliori, Giovanni Battista

    2015-06-01

    Multi-drug resistant tuberculosis (MDR-TB) is caused by Mycobacterium tuberculosis strains resistant to at least two of the most effective anti-tuberculosis drugs (i.e., isoniazid and rifampicin). Therapeutic regimens based on second- and third-line anti-tuberculosis medicines showed poor efficacy, safety, and tolerability profiles. It was estimated that in 2012 the multi-drug resistant tuberculosis incidence ranged from 300,000 to 600,000 cases, mainly diagnosed in the Eastern European and Central Asian countries. The highest proportion of cases is among individuals previously exposed to anti-tuberculosis drugs. Three main conditions can favour the emergence and spread of multi-drug resistant tuberculosis: the poor implementation of the DOTS strategy, the shortage or the poor quality of the anti-tuberculosis drugs, and the poor therapeutic adherence of the patients to the prescribed regimens. Consultation with tuberculosis experts (e.g., consilium) is crucial to tailor the best anti-tuberculosis therapy. New therapeutic options are necessary: bedaquiline and delamanid seem promising drugs; in particular, during the development phase they demonstrated a protective effect against the emergence of further resistances towards the backbone drugs. In the recent past, other antibiotics have been administered off-label: the most relevant efficacy, safety, and tolerability profile was proved in linezolid-, meropenem/clavulanate-, cotrimoxazole-containing regimens. New research and development activities are needed in the diagnostic, therapeutic, preventive fields. PMID:24792579

  16. Low-energy electron transmission through organic monolayers: An estimation of the effective monolayer potential by an excess electron interference

    NASA Astrophysics Data System (ADS)

    Yamane, Hiroyuki; Ito, Kazuyuki; Kera, Satoshi; Okudaira, Koji K.; Ueno, Nobuo

    2002-11-01

    In low-energy-electron transmission spectra of monolayer films of various organic-semiconductor molecules deposited on MoS2 and graphite surfaces, we found that the energy positions of spectral minima are proportional to (n+1/2)2, where n is positive integer and 0, independent of molecules and substrates. Despite the complex structure of each molecule, the (n+1/2)2 rule can be simply explained by the interference of an excess electron passing through the potential of the monolayer on the substrate. Using these results, we estimated the effective potential, the potential width and depth, of the monolayer felt by the injected excess electron.

  17. Childhood tuberculosis.

    PubMed

    Jacobs, R F; Eisenach, K D

    1993-01-01

    The dramatic resurgence and increase in the total number of cases of tuberculous infection and disease in children is alarming in the United States. With poverty, poor access to health care, overcrowding (predominantly in inner-city areas), and an increase in immigration from areas with high endemic rates of tuberculosis, the problem in children will continue to increase. If the impact of coinfection with HIV and M. tuberculosis becomes significant, as it has in adults in the United States, this increase in the total number of cases of tuberculous disease could be staggering. The impact of multiple drug-resistant strains of M. tuberculosis and the current crises in availability of effective antituberculous drugs will need to undergo basic and clinical research. Although the possibility for eradication of M. tuberculosis as a human pathogen in the United States still exists, clinicians must reeducate themselves regarding the epidemiology, pathophysiology, diagnostic work-up, and effective treatment of children with tuberculosis in the current situation of increasing tuberculous disease and resistant organisms in children. PMID:8217004

  18. Transmissivity and storage coefficient estimation by coupling the Cooper Jacob method and modified fuzzy least-squares regression

    NASA Astrophysics Data System (ADS)

    Mathon, Bree R.; Ozbek, Metin M.; Pinder, George F.

    2008-05-01

    SummaryTraditionally the Cooper-Jacob equation is used to determine the transmissivity and the storage coefficient for an aquifer using pump test results. This model, however, is a simplified version of the actual subsurface and does not allow for analysis of the uncertainty that comes from a lack of knowledge about the heterogeneity of the environment under investigation. In this paper, a modified fuzzy least-squares regression (MFLSR) method is developed that uses imprecise pump test data to obtain fuzzy intercept and slope values which are then used in the Cooper-Jacob method. Fuzzy membership functions for the transmissivity and the storage coefficient are then calculated using the extension principle. The supports of the fuzzy membership functions incorporate the transmissivity and storage coefficient values that would be obtained using ordinary least-squares regression and the Cooper-Jacob method. The MFLSR coupled with the Cooper-Jacob method allows the analyst to ascertain the uncertainty that is inherent in the estimated parameters obtained using the simplified Cooper-Jacob method and data that are uncertain due to lack of knowledge regarding the heterogeneity of the aquifer.

  19. [Reconsideration of the admission and discharge criteria of tuberculosis patients in Japan].

    PubMed

    Masuyama, Hidenori; Igari, Hidetoshi

    2013-03-01

    Japanese Ministry of Health, Labour and Welfare issued new criteria for admission and discharge of tuberculosis patients in 2007. The criteria for admission are extended for the patients of the risk of Mycobacterium tuberculosis transmission and of the possible risk of treatment failure. The criteria for discharge are consisted of the 3 factors, (1) symptoms (cough, fever, etc.) are free after the standard chemotherapy of more than 2 weeks, (2) three different sputum smears are negative for acid-fast bacilli after the standard chemotherapy of more than 2 weeks, (3) patients are estimated to adhere to the chemotherapy after discharge and understand the infection control of M. tuberculosis. Although the criteria were simple, the goal was to treat tuberculosis patients successfully and improve treatment outcomes. For the effective operation of these criteria, the network of primary care facilities for early diagnosis and treatment after discharge, tuberculosis treatment facilities for hospitalization and local government including health care center is important. Four speakers proposed the problems and revealed their own resolutions. Three speakers from tuberculosis treatment facilities were positive for the shortening of hospitalization length by modifying the discharging criteria, however 1 speaker from the Tokyo Metropolitan Government emphasized that the regional medical system should be established for the treatment of discharged tuberculosis patient. 1. Reconsideration of admission and discharge criteria for tuberculosis patients: Kazunari TSUYUGUCHI (Department of Infectious Diseases, Clinical Research Center, National Hospital Organization Kinki-chuo Chest Medical Center) According to the present guideline in Japan, three consecutive negative sputum results for smear or culture are required for discharge of tuberculosis (TB) patients, making their duration of hospitalization extremely long. On the other hand, most of the TB ward in Japan consists of big rooms

  20. Channel estimation algorithm for interference suppression in IMDD-OQAM-OFDM transmission systems

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Xiao, Shilin; Bi, Meihua; Liu, Ling; Zhou, Zhao

    2016-04-01

    In this paper, we investigate the intrinsic interference caused by intra-symbol data and channel noise in the intensity-modulation direct-detection OQAM-OFDM (IMDD-OQAM-OFDM) system by theoretical derivation. Based on the analysis, we proposed and experimentally demonstrated a channel estimation algorithm with the combination of IAM-C and frequency-averaging method to combat the effect of these noises. Experimental results show that compared to the common channel estimation algorithms, our algorithm can greatly reduce the error vector magnitude (EVM) and achieve ~1.5 dB sensitivity improvement.

  1. Estimating the Basic Reproductive Number (R0) for African Swine Fever Virus (ASFV) Transmission between Pig Herds in Uganda.

    PubMed

    Barongo, Mike B; Ståhl, Karl; Bett, Bernard; Bishop, Richard P; Fèvre, Eric M; Aliro, Tony; Okoth, Edward; Masembe, Charles; Knobel, Darryn; Ssematimba, Amos

    2015-01-01

    African swine fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic disease of domestic pigs. Insights into the dynamics and scale of virus transmission can be obtained from estimates of the basic reproduction number (R0). We estimate R0 for ASF virus in small holder, free-range pig production system in Gulu, Uganda. The estimation was based on data collected from outbreaks that affected 43 villages (out of the 289 villages with an overall pig population of 26,570) between April 2010 and November 2011. A total of 211 outbreaks met the criteria for inclusion in the study. Three methods were used, specifically; (i) GIS- based identification of the nearest infectious neighbour based on the Euclidean distance between outbreaks, (ii) epidemic doubling time, and (iii) a compartmental susceptible-infectious (SI) model. For implementation of the SI model, three approaches were used namely; curve fitting (CF), a linear regression model (LRM) and the SI/N proportion. The R0 estimates from the nearest infectious neighbour and epidemic doubling time methods were 3.24 and 1.63 respectively. Estimates from the SI-based method were 1.58 for the CF approach, 1.90 for the LRM, and 1.77 for the SI/N proportion. Since all these values were above one, they predict the observed persistence of the virus in the population. We hypothesize that the observed variation in the estimates is a consequence of the data used. Higher resolution and temporally better defined data would likely reduce this variation. This is the first estimate of R0 for ASFV in a free range smallholder pig keeping system in sub-Saharan Africa and highlights the requirement for more efficient application of available disease control measures. PMID:25938429

  2. Estimating the Basic Reproductive Number (R0) for African Swine Fever Virus (ASFV) Transmission between Pig Herds in Uganda

    PubMed Central

    Barongo, Mike B.; Ståhl, Karl; Bett, Bernard; Bishop, Richard P.; Fèvre, Eric M.; Aliro, Tony; Okoth, Edward; Masembe, Charles; Knobel, Darryn; Ssematimba, Amos

    2015-01-01

    African swine fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic disease of domestic pigs. Insights into the dynamics and scale of virus transmission can be obtained from estimates of the basic reproduction number (R0). We estimate R0 for ASF virus in small holder, free-range pig production system in Gulu, Uganda. The estimation was based on data collected from outbreaks that affected 43 villages (out of the 289 villages with an overall pig population of 26,570) between April 2010 and November 2011. A total of 211 outbreaks met the criteria for inclusion in the study. Three methods were used, specifically; (i) GIS- based identification of the nearest infectious neighbour based on the Euclidean distance between outbreaks, (ii) epidemic doubling time, and (iii) a compartmental susceptible-infectious (SI) model. For implementation of the SI model, three approaches were used namely; curve fitting (CF), a linear regression model (LRM) and the SI/N proportion. The R0 estimates from the nearest infectious neighbour and epidemic doubling time methods were 3.24 and 1.63 respectively. Estimates from the SI-based method were 1.58 for the CF approach, 1.90 for the LRM, and 1.77 for the SI/N proportion. Since all these values were above one, they predict the observed persistence of the virus in the population. We hypothesize that the observed variation in the estimates is a consequence of the data used. Higher resolution and temporally better defined data would likely reduce this variation. This is the first estimate of R0 for ASFV in a free range smallholder pig keeping system in sub-Saharan Africa and highlights the requirement for more efficient application of available disease control measures. PMID:25938429

  3. Bovine Tuberculosis in Cattle in the Highlands of Cameroon: Seroprevalence Estimates and Rates of Tuberculin Skin Test Reactors at Modified Cut-Offs

    PubMed Central

    Awah-Ndukum, J.; Kudi, A. C.; Bah, G. S.; Bradley, G.; Tebug, S. F.; Dickmu, P. L.; Njakoi, H. N.; Agharih, W. N.

    2012-01-01

    The aim of this study was to obtain epidemiological estimates of bovine tuberculosis (TB) prevalence in cattle in the highlands of Cameroon using two population-based tuberculin skin test (TST) surveys in the years 2009 and 2010. However, prior to the TST survey in 2010, blood was collected from already chosen cattle for serological assay. Anti-bovine TB antibodies was detected in 37.17% of tested animals and bovine TB prevalence estimates were 3.59%–7.48%, 8.92%–13.25%, 11.77%–17.26% and 13.14%–18.35% for comparative TST at ≥4 mm, ≥3 mm and ≥2 mm cut-off points and single TST, respectively. The agreement between TST and lateral flow was generally higher in TST positive than in TST negative subjects. The K coefficients were 0.119, 0.234, 0.251 and 0.254 for comparative TST at ≥4 mm, ≥3 mm and ≥2 mm cut-off points and the single TST groups, respectively. Chi square statistics revealed that strong (P < 0.05; χ2 > 48) associations existed between seroprevalence rates and TST reactors. The study suggested that using lateral flow assay and TST at severe interpretations could improve the perception of bovine TB in Cameroon. The importance of defining TST at modified cut-offs and disease status by post-mortem detection and mycobacterial culture of TB lesions in local environments cannot be overemphasised. PMID:22567547

  4. Estimation of wave fields of incident beams in a transmission electron microscope by using a small selected-area aperture.

    PubMed

    Morishita, Shigeyuki; Yamasaki, Jun; Tanaka, Nobuo

    2011-01-01

    The direction of an electron beam in a nanometer-sized area is measured directly by utilizing a selected-area aperture. By the measurements at several areas in a beam, the wavefront curvature and thus the defocus value of the beam are detected. From the defocus value, the wave field at the specimen plane is also reproduced in consideration of the influences of the condenser aperture and spherical aberration of the illumination lens. The result shows that phase deviation of 2π is caused only at about 10 nm apart from the beam center in a beam with a typical diameter for high-resolution transmission electron microscopy. Based on the defocus value, the convergence angle of the beam is also estimated to be about 6 mrad without being influenced by the partial coherence, that is, independently of the type of the electron gun. Measuring the defocus values for only two beam diameters enables us to determine geometrical parameters peculiar to the illumination system, based on which wave fields of any beam diameters by any condenser aperture sizes can be estimated. The technique proposed in this paper is effective in evaluating the influence of wavefront curvature of incident beams on various kinds of precise measurements conducted in transmission electron microscopes. PMID:21320861

  5. A Bayesian approach for the estimation and transmission of regularization parameters for reducing blocking artifacts.

    PubMed

    Mateos, J; Katsaggelos, A K; Molina, R

    2000-01-01

    With block-based compression approaches for both still images and sequences of images annoying blocking artifacts are exhibited, primarily at high compression ratios. They are due to the independent processing (quantization) of the block transformed values of the intensity or the displaced frame difference. We propose the application of the hierarchical Bayesian paradigm to the reconstruction of block discrete cosine transform (BDCT) compressed images and the estimation of the required parameters. We derive expressions for the iterative evaluation of these parameters applying the evidence analysis within the hierarchical Bayesian paradigm. The proposed method allows for the combination of parameters estimated at the coder and decoder. The performance of the proposed algorithms is demonstrated experimentally. PMID:18262958

  6. Transmission FTIR derivative spectroscopy for estimation of furosemide in raw material and tablet dosage form

    PubMed Central

    Gallignani, Máximo; Rondón, Rebeca A.; Ovalles, José F.; Brunetto, María R.

    2014-01-01

    A Fourier transform infrared derivative spectroscopy (FTIR-DS) method has been developed for determining furosemide (FUR) in pharmaceutical solid dosage form. The method involves the extraction of FUR from tablets with N,N-dimethylformamide by sonication and direct measurement in liquid phase mode using a reduced path length cell. In general, the spectra were measured in transmission mode and the equipment was configured to collect a spectrum at 4 cm−1 resolution and a 13 s collection time (10 scans co-added). The spectra were collected between 1400 cm−1 and 450 cm−1. Derivative spectroscopy was used for data processing and quantitative measurement using the peak area of the second order spectrum of the major spectral band found at 1165 cm−1 (SO2 stretching of FUR) with baseline correction. The method fulfilled most validation requirements in the 2 mg/mL and 20 mg/mL range, with a 0.9998 coefficient of determination obtained by simple calibration model, and a general coefficient of variation <2%. The mean recovery for the proposed assay method resulted within the (100±3)% over the 80%–120% range of the target concentration. The results agree with a pharmacopoeial method and, therefore, could be considered interchangeable. PMID:26579407

  7. Tuberculosis: General Information

    MedlinePlus

    TB Elimination Tuberculosis: General Information What is TB? Tuberculosis (TB) is a disease caused by germs that are spread from person ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination CS227840_A What Does a Positive Test ...

  8. Global Tuberculosis Report 2015

    MedlinePlus

    ... Feed Youtube Twitter Facebook Google + iTunes Play Store Tuberculosis (TB) Menu Tuberculosis The End TB Strategy Areas ... data News, events and features About us Global tuberculosis report 2015 This is the twentieth global report ...

  9. Urinary tuberculosis

    PubMed Central

    Riddle, P. R.

    1971-01-01

    The present incidence, clinical features and classification of urinary tuberculosis are discussed. Chemotherapy is the mainstay of treatment. The indications for surgical intervention are reviewed and procedures briefly described. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5 PMID:5169185

  10. Secular trends of tuberculosis in western Europe.

    PubMed Central

    Raviglione, M. C.; Sudre, P.; Rieder, H. L.; Spinaci, S.; Kochi, A.

    1993-01-01

    Deaths due to tuberculosis have decreased uniformly in all countries in Western Europe, and most have occurred among those aged > or = 65 years. In recent years, tuberculosis case notifications have continued to decline in Belgium, Finland, France, Germany, and Spain, and have levelled off in Sweden and the United Kingdom; increases have, however, been recorded in Austria, Denmark, Ireland, Italy, Netherlands, Norway, and Switzerland. In Denmark, Netherlands, Norway, Sweden, and Switzerland an increasing number of cases of tuberculosis among foreign-born residents has resulted in a change from the expected downward trend. Human immunodeficiency virus (HIV) infection appears to contribute only marginally to the overall tuberculosis morbidity; however, it appears to be important in Paris and its surrounding areas, and tuberculosis is very common among HIV-infected persons in Italy and Spain. Despite these recent changes in the incidence of tuberculosis, there is currently no evidence of its increased transmission among the youngest age groups of the indigenous populations. Properly designed disease surveillance systems are critical for monitoring the tuberculosis trends so that each country can identify its own high-risk groups and target interventions to prevent, diagnose, and treat the disease. Tuberculosis remains a global disease and because of increasing human migrations, its elimination in Western Europe cannot be envisaged without concomitant improvements in its control in high-incidence, resource-poor countries. PMID:8324847

  11. Tuberculosis vaccine: time to look into future.

    PubMed

    Chawla, Sumit; Garg, Dinesh; Jain, Ram Bilas; Khanna, Pardeep; Choudhary, Satvinder; Sahoo, Soumya; Singh, Inderjeet

    2014-01-01

    Global burden of tuberculosis is nearly 12 million. As per the WHO Global TB Report 2013, there were an estimated 8.6 million incident cases of TB globally in 2012. Tuberculosis is an issue that affects development through its effect on the health of individuals and families. In humans, neither prior latent infection nor recovery from active TB confers reliable protection against reinfection or reactivation disease. The power of vaccines as a public health intervention lies in their ability to reduce onward transmission of disease as much as in their ability to protect vaccinated individuals; a feature generally referred to as "herd immunity." MVA85A is a booster vaccine, used in con-junction with BCG as part of a prime-boost strategy. BCG serves as the prime vaccination and MVA85A as the boost, operating under the theory that the addition of MVA85A will produce a better immune response and more protection against TB than BCG vaccination alone. There is a critical need to raise the profile of TB vaccine research at the community, national, regional, and global levels in order to generate support and political will, increase investment, create an enabling and supportive environment for clinical trials, and lay the groundwork for acceptance and adoption of new TB vaccines once licensed. PMID:24231233

  12. [Tuberculosis control of urban areas in Japan].

    PubMed

    2000-10-01

    City Institute Laboratory of Health and Environment) DNA fingerprinting establishes the genetic relatedness of Mycobacterium tuberculosis isolates and has become a powerful tool in tuberculosis epidemiology. To use DNA fingerprinting to assess the efficacy of current tuberculosis infection-control practices. Combining conventional epidemiologic techniques with DNA fingerprinting of M. tuberculosis can improve the understanding of how tuberculosis is transmitted. Patients were assigned to clusters based on mycobacterial isolates with identical DNA fingerprints. Clusters were assumed to have arisen from recent transmission. We analyzed M. tuberculosis isolates from patients reported to the tuberculosis registry by RFLP techniques. These results were interpreted along with demographic data. Patients infected with the same strains were identified according to their RFLP patterns, and patients with identical patterns were grouped in clusters. RFLP patterns of high incidence districts have more variations than other areas. This suggests that the source of tuberculosis infection are quite diverse and complicated. Tuberculosis patients may accumulate to high incidence districts from other places after infection. 4. Structure of High Incidence of Tuberculosis and Control Plan in Osaka City: Yoichi TATSUMI (Bureau of Infection Control, Osaka City Office) The case notification rate in Osaka City is the highest in Japan. That of all TB cases and smear positive TB cases was 1573 and 216 per 100,000 population in 1997 at Airin District in Osaka City. The main reason for this highest incidence rate is that there are many homeless people and it is a mobile population. Most of residents are daily laborers. They come from all over Japan and stay there, mainly in rented rooms, to look for jobs. Thousands of homeless people also live in tents on streets or in parks. We are making to new strategic plan to intensify tuberculosis control measures throughout the city. Osaka city government h

  13. Type curve and numerical solutions for estimation of Transmissivity and Storage coefficient with variable discharge condition

    NASA Astrophysics Data System (ADS)

    Zhang, Guowei

    2013-01-01

    SummaryMost of the coal mines of China are mining under the ground, so the artesian test which is one of the aquifer tests is conducted normally several hundred of meters below the earth surface. And the target aquifer is with very high hydraulic pressure, sometimes more than 3 MPa. Because of the high hydraulic pressure, it is most difficult to control the rate of flow out of the artesian well. Moreover, the velocity of flow out of the well cannot descend rapidly to zero, thus the analytical solution of Jacob and Lohman type curve for the artesian test will not be applicable. It is more reasonable if analyzing this test as a pumping test but with variable discharge. It is considered to rebuild that hydrogeological conceptual model in this paper. This conceptual model is similar with Theis model but with the variable discharge merely. And a general equation for any discharge variability is given. Its application for the linearly decreasing discharge is presented subsequently, and a type curve of this equation with linearly decreasing discharge will be given as well. Then a simple numerical model using FEFLOW will be built to simulate the linearly decreasing discharge from giving several different groups of the values of Transmissivity (T) and Storage coefficient (S). Both of them are much important hydrogeological parameters, and will be evaluated by using the type curve developed for this linear decreasing discharge well. The error between the given values of T and S in FEFLOW and the values of those calculated by matching point are much small. The solution gives really satisfactory values of these hydrogeological parameters.

  14. Mycobacterium microti tuberculosis in its maintenance host, the field vole (Microtus agrestis): characterization of the disease and possible routes of transmission.

    PubMed

    Kipar, A; Burthe, S J; Hetzel, U; Rokia, M Abo; Telfer, S; Lambin, X; Birtles, R J; Begon, M; Bennett, M

    2014-09-01

    The field vole (Microtus agrestis) is a known maintenance host of Mycobacterium microti. Previous studies have shown that infected animals develop tuberculosis. However, the disease is also known in cats and is sporadically reported from humans and other mammalian species. We examined trapped field voles from an endemic area, using a range of diagnostic approaches. These confirmed that a combination of gross and histological examination with culture is most appropriate to identify the true prevalence of the disease, which was shown to be more than 13% at times when older animals that have previously been shown to be more likely to develop the disease dominate the population. The thorough pathological examination of diseased animals showed that voles generally develop systemic disease with most frequent involvement of spleen and liver, followed by skin, lymph nodes, and lungs. The morphology of the lesions was consistent with active disease, and their distribution suggested skin wounds or oral and/or aerogenic infection as the main portal of entry. The demonstration of mycobacteria in open skin lesions, airways, and salivary glands indicated bacterial shedding from the skin and with sputum and saliva. This suggests not only the environment but also direct contact and devouring as likely sources of infection. PMID:24334995

  15. Mycobacterium microti Tuberculosis in Its Maintenance Host, the Field Vole (Microtus agrestis): Characterization of the Disease and Possible Routes of Transmission

    PubMed Central

    Kipar, A.; Burthe, S. J.; Hetzel, U.; Abo Rokia, M.; Telfer, S.; Lambin, X.; Birtles, R. J.; Begon, M.; Bennett, M.

    2014-01-01

    The field vole (Microtus agrestis) is a known maintenance host of Mycobacterium microti. Previous studies have shown that infected animals develop tuberculosis. However, the disease is also known in cats and is sporadically reported from humans and other mammalian species. We examined trapped field voles from an endemic area, using a range of diagnostic approaches. These confirmed that a combination of gross and histological examination with culture is most appropriate to identify the true prevalence of the disease, which was shown to be more than 13% at times when older animals that have previously been shown to be more likely to develop the disease dominate the population. The thorough pathological examination of diseased animals showed that voles generally develop systemic disease with most frequent involvement of spleen and liver, followed by skin, lymph nodes, and lungs. The morphology of the lesions was consistent with active disease, and their distribution suggested skin wounds or oral and/or aerogenic infection as the main portal of entry. The demonstration of mycobacteria in open skin lesions, airways, and salivary glands indicated bacterial shedding from the skin and with sputum and saliva. This suggests not only the environment but also direct contact and devouring as likely sources of infection. PMID:24334995

  16. Importance and mitigation of the risk of spillback transmission of Mycobacterium bovis infection for eradication of bovine tuberculosis from wildlife in New Zealand.

    PubMed

    Barron, M C; Nugent, G; Cross, M L

    2013-07-01

    Introduced brushtail possums (Trichosurus vulpecula) are wildlife maintenance hosts for Mycobacterium bovis in New Zealand, often living sympatrically with other potential hosts, including wild red deer (Cervus elaphus scoticus). Population control of possums has been predicted to eradicate tuberculosis (TB) from New Zealand wildlife ; however, there is concern that long-lived M. bovis-infected deer could represent a ‘ spillback’ risk for TB re-establishment (particularly when possum populations recover after cessation of intensive control). We constructed a time-, age- and sex-structured, deer/TB population generic model and simulated the outcomes of deer control on this potential spillback risk. Maintaining intensive possum control on a 5-year cycle, the predicted spillback risk period after TB eradication from possums is ~7 years, while the probability of TB re-establishing in possums over that period is ~6%. Additional targeted control of deer would reduce the risk period and probability of spillback; however, even with high population reductions (up to 80%) only modest decreases in risk and risk period would be achieved. We conclude that possum control alone remains the best strategy for achieving TB eradication from New Zealand habitats in which possums and wild deer are the main M. bovis hosts. PMID:23211646

  17. Estimation of Plasmodium falciparum Transmission Intensity in Lilongwe, Malawi, by Microscopy, Rapid Diagnostic Testing, and Nucleic Acid Detection.

    PubMed

    Parr, Jonathan B; Belson, Connor; Patel, Jaymin C; Hoffman, Irving F; Kamthunzi, Portia; Martinson, Francis; Tegha, Gerald; Thengolose, Isaac; Drakeley, Chris; Meshnick, Steven R; Escamillia, Veronica; Emch, Michael; Juliano, Jonathan J

    2016-08-01

    Estimates of malaria transmission intensity (MTI) typically rely upon microscopy or rapid diagnostic testing (RDT). However, these methods are less sensitive than nucleic acid amplification techniques and may underestimate parasite prevalence. We compared microscopy, RDT, and polymerase chain reaction (PCR) for the diagnosis of Plasmodium falciparum parasitemia as part of an MTI study of 800 children and adults conducted in Lilongwe, Malawi. PCR detected more cases of parasitemia than microscopy or RDT. Age less than 5 years predicted parasitemia detected by PCR alone (adjusted odds ratio = 1.61, 95% confidence interval = 1.09-2.38, Wald P = 0.02). In addition, we identified one P. falciparum parasite with a false-negative RDT result due to a suspected deletion of the histidine-rich protein 2 (hrp2) gene and used a novel, ultrasensitive PCR assay to detect low-level parasitemia missed by traditional PCR. Molecular methods should be considered for use in future transmission studies as a supplement to RDT or microscopy. PMID:27325802

  18. Estimated transmission beam pattern of clicks recorded from free-ranging white-beaked dolphins (Lagenorhynchus albirostris)

    NASA Astrophysics Data System (ADS)

    Rasmussen, Marianne H.; Wahlberg, Magnus; Miller, Lee A.

    2004-09-01

    Recordings were made from white-beaked dolphins in Icelandic waters using a four-hydrophone array in a star configuration. The acoustic signals were amplified and sampled to a hard disk at a rate of 800 kHz per channel. The 3 and 10 dB beamwidths were calculated to be 8° and 10°, respectively, indicating a narrower transmission beam for white-beaked dolphins than that reported for bottlenose dolphins (Tursiops truncatus). The beamwidth was more similar to that found for belugas (Delphinapterus lucas). The measured beam pattern included large side lobes, perhaps due to the inclusion of off-axis clicks, even after applying several criteria to select only on-axis clicks. The directivity index was calculated to be 18 dB when using all data for angles from 0°-50°. The calculated sound radiation from a circular piston with a radius of 6 cm driven by a white-beaked dolphin click had a beam pattern very similar to the measured beam pattern for the main transmission lobe of the white-beaked dolphin. The directivity index was 29 dB. This is the first attempt to estimate the directionality index of dolphins in the field. [Work supported by the Oticon Foundation and the Danish National Research Council.

  19. Estimating transmission of avian influenza in wild birds from incomplete epizootic data: implications for surveillance and disease spreac

    USGS Publications Warehouse

    Viviane Henaux; Jane Parmley; Catherine Soos; Samuel, Michael D.

    2013-01-01

    Synthesis and applications. Our study highlights the potential of integrating incomplete surveillance data with epizootic models to quantify disease transmission and immunity. This modelling approach provides an important tool to understand spatial and temporal epizootic dynamics and inform disease surveillance. Our findings suggest focusing highly pathogenic avian influenza virus (HPAIv) surveillance on postbreeding areas where mortality of immunologically naïve hatch-year birds is most likely to occur, and collecting serology to enhance HPAIv detection. Our modelling approach can integrate various types of disease data facilitating its use with data from other surveillance programs (as illustrated by the estimation of infection rate during an HPAIv outbreak in mute swansCygnus olor in Europe).

  20. Estimating the Impact of Reducing Under-Nutrition on the Tuberculosis Epidemic in the Central Eastern States of India: A Dynamic Modeling Study

    PubMed Central

    Oxlade, Olivia; Huang, Chuan-Chin; Murray, Megan

    2015-01-01

    Background Tuberculosis (TB) and under-nutrition are widespread in many low and middle-income countries. Momentum to prioritize under-nutrition has been growing at an international level, as demonstrated by the "Scaling Up Nutrition" movement. Low body mass index is an important risk factor for developing TB disease. The objective of this study was to project future trends in TB related outcomes under different scenarios for reducing under-nutrition in the adult population in the Central Eastern states of India. Methods A compartmental TB transmission model stratified by body mass index was parameterized using national and regional data from India. We compared TB related mortality and incidence under several scenarios that represented a range of policies and programs designed to reduce the prevalence of under-nutrition, based on the experience and observed trends in similar countries. Results The modeled nutrition intervention scenarios brought about reductions in TB incidence and TB related mortality in the Central Eastern Indian states ranging from 43% to 71% and 40% to 68% respectively, relative to the scenario of no nutritional intervention. Modest reductions in under-nutrition averted 4.8 (95% UR 0.5, 17.1) million TB cases and 1.6 (95% UR 0.5, 5.2) million TB related deaths over a period of 20 years of intervention, relative to the scenario of no nutritional intervention. Complete elimination of under-nutrition in the Central Eastern states averted 9.4 (95% UR 1.5, 30.6) million TB cases and 3.2 (95% UR 0.7-, 10.1) million TB related deaths, relative to the scenario of no nutritional intervention. Conclusion Our study suggests that intervening on under-nutrition could have a substantial impact on TB incidence and mortality in areas with high prevalence of under-nutrition, even if only small gains in under-nutrition can be achieved. Focusing on under-nutrition may be an effective way to reduce both rates of TB and other diseases associated with under

  1. Tuberculosis Contact Investigations--United States, 2003-2012.

    PubMed

    Young, Kai H; Ehman, Melissa; Reves, Randall; Peterson Maddox, Brandy L; Khan, Awal; Chorba, Terence L; Jereb, John

    2016-01-01

    Mycobacterium tuberculosis is transmitted through the air from an infectious patient (index patient) to other persons (contacts) who share space. Exposure to M. tuberculosis can result in tuberculosis (TB) disease or latent TB infection (LTBI), which has no clinical symptoms or radiologic evidence of disease. The cycle of transmission can be ended by isolating and treating patients with TB disease, examining contacts, and treating LTBI to prevent progression to TB disease. CDC systematically collects aggregate data on contact investigations from the 50 states, the District of Columbia (DC), and Puerto Rico. Data from 2003-2012 were analyzed for trends in yields from contact investigations, in terms of numbers of contacts elicited and examined and the estimated number of TB cases averted through treatment of LTBI among contacts in 2012. During 2003-2012, the number of TB cases decreased, while the number of contacts listed per index patient with contacts elicited increased. In 2012, U.S. public health authorities reported 9,945 cases of TB disease (1) and 105,100 contacts. Among these contacts, 84,998 (80.9%) were examined; TB was diagnosed in 532 (0.6%) and LTBI in 15,411 (18.1%). Among contacts with LTBI, 10,137 (65.8%) started treatment, and 6,689 (43.4% of all contacts with LTBI) completed treatment. By investigating contacts in 2012, an estimated 128 TB cases (34% of all potential cases) over the initial 5 years were averted, but an additional 248 cases (66%) might have been averted if all potentially contagious TB patients had contacts elicited, all contacts were examined, and all infected contacts completed treatment. Enhancing contact investigation activities, particularly by ensuring completion of treatment by contacts recently infected with M. tuberculosis, is essential to achieve the goal of TB elimination. PMID:26720627

  2. A mathematical model for Plasmodium vivax malaria transmission: estimation of the impact of transmission-blocking immunity in an endemic area.

    PubMed

    De Zoysa, A P; Mendis, C; Gamage-Mendis, A C; Weerasinghe, S; Herath, P R; Mendis, K N

    1991-01-01

    We have developed a multi-state mathematical model to describe the transmission of Plasmodium vivax malaria; the model accommodates variable transmission-blocking/enhancing immunity during the course of a blood infection, a short memory for boosting immunity, and relapses. Using the model, we simulated the incidence of human malaria, sporozoite rates in the vector population, and the level of transmission-blocking immunity for the infected population over a period of time. Field data from an epidemiological study conducted in Kataragama in the south of Sri Lanka were used to test the results obtained. The incidence of malaria during the study period was simulated satisfactorily. The impact of naturally-acquired transmission-blocking immunity on malaria transmission under different vectorial capacities was also simulated. The results show that at low vectorial capacities, e.g., just above the threshold for transmission, the effect of transmission-blocking immunity is very significant; however, the effect is lower at higher vectorial capacities. PMID:1786621

  3. Tuberculosis Outbreak in Marijuana Users, Seattle, Washington, 2004

    PubMed Central

    Oren, Eyal; Haddad, Maryam B.; Lake, Linda K.; Harrington, Theresa A.; Ijaz, Kashef; Narita, Masahiro

    2006-01-01

    Matching Mycobacterium tuberculosis isolates were noted among 11 young tuberculosis patients socially linked through illicit drug–related activities. A large proportion of their friends, 14 (64%) of 22, had positive tuberculin skin-test results. The behavior of "hotboxing" (smoking marijuana inside a closed car with friends to repeatedly inhale exhaled smoke) fueled transmission. PMID:16836841

  4. Estimating electricity storage power rating and discharge duration for utility transmission and distribution deferral :a study for the DOE energy storage program.

    SciTech Connect

    Eyer, James M. (Distributed Utility Associates, Livermore, CA); Butler, Paul Charles; Iannucci, Joseph J., Jr.

    2005-11-01

    This report describes a methodology for estimating the power and energy capacities for electricity energy storage systems that can be used to defer costly upgrades to fully overloaded, or nearly overloaded, transmission and distribution (T&D) nodes. This ''sizing'' methodology may be used to estimate the amount of storage needed so that T&D upgrades may be deferred for one year. The same methodology can also be used to estimate the characteristics of storage needed for subsequent years of deferral.

  5. Tuberculosis in domestic animal species.

    PubMed

    Pesciaroli, M; Alvarez, J; Boniotti, M B; Cagiola, M; Di Marco, V; Marianelli, C; Pacciarini, M; Pasquali, P

    2014-10-01

    M. bovis and M. caprae, members of the Mycobacterium tuberculosis complex (MTC), are the major causative agents of tuberculosis in domestic animals. Notably, M. bovis exhibits a wide host range; the infection has been reported in many domesticated animals and free or captive wildlife. Despite most of them acting as spill-over hosts in particular epidemiological scenarios, some domesticated species as pigs, camelids and goats may display high rates of infection and possibly play a role in the inter-species transmission of the disease. The aim of this review is to make an updated overview of the susceptibility and the role in the transmission of the disease of the most common domesticated animals species such as small ruminants, pigs, horses, camelids, dogs and cats. An overview of the diagnostic approaches to detect the infection in each of the species included in the review is also presented. PMID:25151859

  6. Spinal Tuberculosis

    PubMed Central

    Ekinci, Safak; Tatar, Oner; Akpancar, Serkan; Bilgic, Serkan; Ersen, Omer

    2015-01-01

    Spinal tuberculosis (TB) is a significant form of TB, causing spinal deformity and paralysis. Early diagnosis and treatment are crucial for avoiding multivertebral destruction and are critical for improving outcomes in spinal TB. We believe that appropriate treatment method should be implemented at the early stage of this disease and that the Gulhane Askeri Tıp Akademisi classification system can be considered a practical guide for spinal TB treatment planning in all countries. PMID:26609247

  7. Diagnosis of Childhood Tuberculosis and Host RNA Expression in Africa

    PubMed Central

    Banwell, Claire M.; Chagaluka, George; Crampin, Amelia C.; Dockrell, Hazel M.; French, Neil; Hamilton, Melissa S.; Hibberd, Martin L.; Kern, Florian; Langford, Paul R.; Ling, Ling; Mlotha, Rachel; Ottenhoff, Tom H.M.; Pienaar, Sandy; Pillay, Vashini; Scott, J. Anthony G.; Twahir, Hemed; Wilkinson, Robert J.

    2014-01-01

    BACKGROUND Improved diagnostic tests for tuberculosis in children are needed. We hypothesized that transcriptional signatures of host blood could be used to distinguish tuberculosis from other diseases in African children who either were or were not infected with the human immunodeficiency virus (HIV). METHODS The study population comprised prospective cohorts of children who were undergoing evaluation for suspected tuberculosis in South Africa (655 children), Malawi (701 children), and Kenya (1599 children). Patients were assigned to groups according to whether the diagnosis was culture-confirmed tuberculosis, culture-negative tuberculosis, diseases other than tuberculosis, or latent tuberculosis infection. Diagnostic signatures distinguishing tuberculosis from other diseases and from latent tuberculosis infection were identified from genomewide analysis of RNA expression in host blood. RESULTS We identified a 51-transcript signature distinguishing tuberculosis from other diseases in the South African and Malawian children (the discovery cohort). In the Kenyan children (the validation cohort), a risk score based on the signature for tuberculosis and for diseases other than tuberculosis showed a sensitivity of 82.9% (95% confidence interval [CI], 68.6 to 94.3) and a specificity of 83.6% (95% CI, 74.6 to 92.7) for the diagnosis of culture-confirmed tuberculosis. Among patients with cultures negative for Mycobacterium tuberculosis who were treated for tuberculosis (those with highly probable, probable, or possible cases of tuberculosis), the estimated sensitivity was 62.5 to 82.3%, 42.1 to 80.8%, and 35.3 to 79.6%, respectively, for different estimates of actual tuberculosis in the groups. In comparison, the sensitivity of the Xpert MTB/RIF assay for molecular detection of M. tuberculosis DNA in cases of culture-confirmed tuberculosis was 54.3% (95% CI, 37.1 to 68.6), and the sensitivity in highly probable, probable, or possible cases was an estimated 25.0 to 35

  8. Tuberculosis (For Parents)

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Tuberculosis KidsHealth > For Parents > Tuberculosis Print A A A Text Size What's in ... When to You Call the Doctor en español Tuberculosis Tuberculosis (popularly known as "TB") is a disease ...

  9. Animal models of cavitation in pulmonary tuberculosis.

    PubMed

    Helke, Kris L; Mankowski, Joseph L; Manabe, Yukari C

    2006-09-01

    Transmission of tuberculosis occurs with the highest frequency from patients with extensive, cavitary, pulmonary disease and positive sputum smear microscopy. In animal models of tuberculosis, the development of caseous necrosis is an important prerequisite for the formation of cavities although the immunological triggers for liquefaction are unknown. We review the relative merits and the information gleaned from the available animal models of pulmonary cavitation. Understanding the host-pathogen interaction important to the formation of cavities may lead to new strategies to prevent cavitation and thereby, block transmission. PMID:16359922

  10. AQUIFER TRANSMISSIVITY

    EPA Science Inventory

    Evaluation of groundwater resources requires the knowledge of the capacity of aquifers to store and transmit ground water. This requires estimates of key hydraulic parameters, such as the transmissivity, among others. The transmissivity T (m2/sec) is a hydrauli...

  11. Nonlinear experimental dye-doped nematic liquid crystal optical transmission spectra estimated by neural network empirical physical formulas

    NASA Astrophysics Data System (ADS)

    Yildiz, Nihat; San, Sait Eren; Köysal, Oğuz

    2010-09-01

    In this paper, two complementary objectives related to optical transmission spectra of nematic liquid crystals (NLCs) were achieved. First, at room temperature, for both pure and dye (DR9) doped E7 NLCs, the 10-250 W halogen lamp transmission spectra (wavelength 400-1200 nm) were measured at various bias voltages. Second, because the measured spectra were inherently highly nonlinear, it was difficult to construct explicit empirical physical formulas (EPFs) to employ as transmittance functions. To avoid this difficulty, layered feedforward neural networks (LFNNs) were used to construct explicit EPFs for these theoretically unknown nonlinear NLC transmittance functions. As we theoretically showed in a previous work, a LFNN, as an excellent nonlinear function approximator, is highly relevant to EPF construction. The LFNN-EPFs efficiently and consistently estimated both the measured and yet-to-be-measured nonlinear transmittance response values. The experimentally obtained doping ratio dependencies and applied bias voltage responses of transmittance were also confirmed by LFFN-EPFs. This clearly indicates that physical laws embedded in the physical data can be faithfully extracted by the suitable LFNNs. The extraordinary success achieved with LFNN here suggests two potential applications. First, although not attempted here, these LFNN-EPFs, by such mathematical operations as derivation, integration, minimization etc., can be used to obtain further transmittance related functions of NLCs. Second, for a given NLC response function, whose theoretical nonlinear functional form is yet unknown, a suitable experimental data based LFNN-EPF can be constructed to predict the yet-to-be-measured values.

  12. [Tuberculosis--a neverending story].

    PubMed

    Dzieciołowska-Baran, Edyta; Gawlikowska-Sroka, Aleksandra

    2013-01-01

    It is estimated that over one third of the human population is now exposed or has been exposed in the past to Mycobacterium tuberculosis, and new infections occur in the world at a rate of one per second. The history of tuberculosis is long and very interesting, because before the isolation of mycobacteria and the finding of a cure, the disease mercilessly killed thousands of people and deprived doctors of hope. Robert Koch's momentous discovery was a major breakthrough in the fight against tuberculosis. Unfortunately, the disease has never been fully controlled. Tuberculosis is a chronic infectious disease localized in 90-95% of cases in the lungs, and therefore it is extremely difficult to diagnose unequivocally in paleopathological material. Only the form of osteo-arthritis leaves traces in archaeological material. The earliest evidence of tuberculosis (the location of the spine, Pott's disease) in the form of fossils is dated to before 8000 BC. Another very old trace is considered to be human remains from the Neolithic period (ca 5000 BC), found near Heidelberg, where changes in the thoracic spine are typical for spondylitis in tuberculosa. Constant growth in the incidence of new cases in the world can be observed today. Not everyone infected will develop the full-blown disease. The infection may remain dormant. However, one in ten latent infections will subsequently be activated, leading, if not treated, to the death of almost half of the patients. PMID:25026769

  13. Molecular epidemiology of tuberculosis in Cambodian children.

    PubMed

    Schopfer, K; Rieder, H L; Steinlin-Schopfer, J F; van Soolingen, D; Bodmer, T; Chantana, Y; Studer, P; Laurent, D; Zwahlen, M; Richner, B

    2015-04-01

    SUMMARY We analysed Mycobacterium tuberculosis strains from children, hospitalized from January 2004 to July 2008 in the largest paediatric hospital complex in Cambodia. Specimens were tested for drug susceptibility and genotypes. From the 260 children, 161 strains were available. The East African-Indian genotype family was the most common (59.0%), increasing in frequency with distance from the Phnom Penh area, while the frequency of the Beijing genotype family strains decreased. The drug resistance pattern showed a similar geographical gradient: lowest in the northwest (4.6%), intermediate in the central (17.1%), and highest in the southeastern (30.8%) parts of the country. Three children (1.9%) had multidrug-resistant tuberculosis. The Beijing genotype and streptomycin resistance were significantly associated (P < 0.001). As tuberculosis in children reflects recent transmission patterns in the community, multidrug resistance levels inform about the current quality of the tuberculosis programme. PMID:25050615

  14. [The bacteriology of tuberculosis and non-tuberculosis mycobacterial infections].

    PubMed

    Wyplosz, B; Truffot-Pernot, C; Robert, J; Jarlier, V; Grosset, J

    1997-12-01

    Changing incidence and nature of mycobacterial infections subsequent to the historical regression of tuberculosis and the acquired human immunodeficiency syndrome (AIDS) epidemic, as well as the development of new technical tools for molecular biology, have profoundly modified the methods used for the bacteriological diagnosis of mycobacteria infections. Although microscopic search for acid-fast bacilli, culture and antibiotic resistance tests on Löwenstein-Jensen medium remain the reference methods, more rapid and sophisticated methods are now available. Culture on radiolabeled media using the Bactec system has shortened the delay for positive culture and interpretable antibiotic sensitivity tests. Molecular techniques allow: 1) rapid identification of the most frequently isolated mycobacteria strains, including the most frequent laboratory contaminant M. gordonae, with genome probes; 2) genome typing of M. tuberculosis strains to trace interhuman transmission, detect recurrence or exogenous reinfection or demonstrate laboratory contamination; 3) rapid detection of rifampicin resistance; and 4) direct detection of M. tuberculosis and M. avium in pathological specimens. The role of mycobacteria in the environment causing opportunistic infections, atypical mycobacteria or non-tuberculosis mycobacteria (NTM), particularly the aviaire complex, has grown considerably. Isolation and identification relies on methods used to detect bacilli as well as blood cultures and analysis of fecal matter. NTM are naturally resistant to most of the antituberculosis antibiotics but are sometimes sensitive to aminoglycosides, fluoroquinolones or new macrolides. PMID:9496590

  15. The resurgence of tuberculosis.

    PubMed

    Parry, C; Davies, P D

    1996-01-01

    A lack of reliable statistics makes tuberculosis (TB) trends in developing countries difficult to estimate. Nonetheless, the World Health Organization and the International Union against Tuberculosis and Lung Disease estimated in 1990 that one-third of the world's population was infected with the tubercle bacillus and that there were 7-8 million new cases of TB annually. 95% of the new cases occurred in the developing world, with more than 5 million in Asia and the Western Pacific and more than 1 million in sub-Saharan Africa. Almost 80% of TB cases in developing countries occur among those under age 50 years. The global annual mortality was estimated at 2.5 million, with 98% of deaths occurring in developing countries. Worldwide, TB is believed to be responsible for 25% of avoidable deaths in young adults. There has been no significant decline in the average annual risk of infection in most developing countries due to incomplete coverage by control programs and inadequate cure rates. The interaction of HIV infection with TB is another factor which contributes to the deteriorating TB situation in many developing countries. Countries with a high population growth rate and little decline in the annual risk of infection should expect either a static or increasing level of TB disease. Immigration from developing countries, HIV infection, poverty, unemployment, homelessness, overcrowding, and population aging contribute to the spread of TB in developed countries. Drug resistance thwarts the control of TB worldwide. PMID:8972116

  16. Transmission loss estimation of three-dimensional silencers by system graph approach using multi-domain BEM

    NASA Astrophysics Data System (ADS)

    Park, Young-Bum; Ju, Hyeon-Don; Lee, Shi-Bok

    2009-12-01

    Transmission loss (TL) estimation of three-dimensional silencers with complicated internal structures such as inlet/outlet tubes, thin baffles, perforated tubes, and sound absorbing materials is a demanding job even by powerful numerical approach such as FEM (finite element method) or BEM (boundary element method). The transfer matrix method using the multi-domain BEM data may be an efficient tool to deal with multi-branched acoustic systems but the method has limitation in application since it is based on the assumption of plane wave propagation at the interface of sub-domains. Assembling the whole system equation directly using the multi-domain BEM data is a considerable means to deal with three-dimensional acoustic components, but the intermediate pseudo-unknown variables in the equation assembling process may be too large. An efficient practical method by system graph approach and multi-domain BEM is proposed to formulate the condensed overall acoustic system equation for the whole acoustic system, only with unknown sound pressures on the sub-domain boundaries. The solutions of the overall equation are used to compute the TL of silencers. An air suction silencer for air compressors is tested numerically and experimentally and both results are compared to back up the suggested method.

  17. Estimation of ibuprofen in urine and tablet formulations by transmission Fourier Transform Infrared spectroscopy by partial least square.

    PubMed

    Khaskheli, Abdul Rauf; Sirajuddin; Sherazi, S T H; Mahesar, S A; Kandhro, Aftab A; Kalwar, Nazar Hussain; Mallah, Muhammad Ali

    2013-02-01

    A rapid, reliable and cost effective analytical procedure for the estimation of ibuprofen in pharmaceutical formulations and human urine samples was developed using transmission Fourier Transform Infrared (FT-IR) spectroscopy. For the determination of ibuprofen, a KBr window with 500 μm spacer was used to acquire the FT-IR spectra of standards, pharmaceuticals as well as urine samples. Partial least square (PLS) calibration model was developed based on region from 1807 to 1,461 cm(-1) using ibuprofen standards ranging from 10 to 100 μg ml(-1). The developed model was evaluated by cross-validation to determine standard error of the models such as root mean square error of calibration (RMSEC), root mean square error of cross validation (RMSECV) and root mean square error of prediction (RMSEP). The coefficient of determination (R(2)) achieved was 0.998 with minimum errors in RMSEC, RMSECV and RMSEP with the value of 1.89%, 1.63% and 4.07%, respectively. The method was successfully applied to urine and pharmaceutical samples and obtained good recovery (98-102%). PMID:23237846

  18. Estimation of ibuprofen in urine and tablet formulations by transmission Fourier Transform Infrared spectroscopy by partial least square

    NASA Astrophysics Data System (ADS)

    Khaskheli, Abdul Rauf; Sirajuddin; Sherazi, S. T. H.; Mahesar, S. A.; Kandhro, Aftab A.; Kalwar, Nazar Hussain; Mallah, Muhammad Ali

    2013-02-01

    A rapid, reliable and cost effective analytical procedure for the estimation of ibuprofen in pharmaceutical formulations and human urine samples was developed using transmission Fourier Transform Infrared (FT-IR) spectroscopy. For the determination of ibuprofen, a KBr window with 500 μm spacer was used to acquire the FT-IR spectra of standards, pharmaceuticals as well as urine samples. Partial least square (PLS) calibration model was developed based on region from 1807 to 1461 cm-1 using ibuprofen standards ranging from 10 to 100 μg ml-1. The developed model was evaluated by cross-validation to determine standard error of the models such as root mean square error of calibration (RMSEC), root mean square error of cross validation (RMSECV) and root mean square error of prediction (RMSEP). The coefficient of determination (R2) achieved was 0.998 with minimum errors in RMSEC, RMSECV and RMSEP with the value of 1.89%, 1.63% and 4.07%, respectively. The method was successfully applied to urine and pharmaceutical samples and obtained good recovery (98-102%).

  19. Differential influence of nutrient-starved Mycobacterium tuberculosis on adaptive immunity results in progressive tuberculosis disease and pathology.

    PubMed

    Dietrich, Jes; Roy, Sugata; Rosenkrands, Ida; Lindenstrøm, Thomas; Filskov, Jonathan; Rasmussen, Erik Michael; Cassidy, Joseph; Andersen, Peter

    2015-12-01

    When infected with Mycobacterium tuberculosis, most individuals will remain clinically healthy but latently infected. Latent infection has been proposed to partially involve M. tuberculosis in a nonreplicating stage, which therefore represents an M. tuberculosis phenotype that the immune system most likely will encounter during latency. It is therefore relevant to examine how this particular nonreplicating form of M. tuberculosis interacts with the host immune system. To study this, we first induced a state of nonreplication through prolonged nutrient starvation of M. tuberculosis in vitro. This resulted in nonreplicating persistence even after prolonged culture in phosphate-buffered saline. Infection with either exponentially growing M. tuberculosis or nutrient-starved M. tuberculosis resulted in similar lung CFU levels in the first phase of the infection. However, between week 3 and 6 postinfection, there was a very pronounced increase in bacterial levels and associated lung pathology in nutrient-starved-M. tuberculosis-infected mice. This was associated with a shift from CD4 T cells that coexpressed gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) or IFN-γ, TNF-α, and interleukin-2 to T cells that only expressed IFN-γ. Thus, nonreplicating M. tuberculosis induced through nutrient starvation promotes a bacterial form that is genetically identical to exponentially growing M. tuberculosis yet characterized by a differential impact on the immune system that may be involved in undermining host antimycobacterial immunity and facilitate increased pathology and transmission. PMID:26416911

  20. Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection Protocol.

    PubMed

    Santos, Nuno; Santos, Catarina; Valente, Teresa; Gortázar, Christian; Almeida, Virgílio; Correia-Neves, Margarida

    2015-01-01

    Environmental contamination with Mycobacterium tuberculosis complex (MTC) has been considered crucial for bovine tuberculosis persistence in multi-host-pathogen systems. However, MTC contamination has been difficult to detect due to methodological issues. In an attempt to overcome this limitation we developed an improved protocol for the detection of MTC DNA. MTC DNA concentration was estimated by the Most Probable Number (MPN) method. Making use of this protocol we showed that MTC contamination is widespread in different types of environmental samples from the Iberian Peninsula, which supports indirect transmission as a contributing mechanism for the maintenance of bovine tuberculosis in this multi-host-pathogen system. The proportion of MTC DNA positive samples was higher in the bovine tuberculosis-infected than in presumed negative area (0.32 and 0.18, respectively). Detection varied with the type of environmental sample and was more frequent in sediment from dams and less frequent in water also from dams (0.22 and 0.05, respectively). The proportion of MTC-positive samples was significantly higher in spring (p<0.001), but MTC DNA concentration per sample was higher in autumn and lower in summer. The average MTC DNA concentration in positive samples was 0.82 MPN/g (CI95 0.70-0.98 MPN/g). We were further able to amplify a DNA sequence specific of Mycobacterium bovis/caprae in 4 environmental samples from the bTB-infected area. PMID:26561038

  1. Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection Protocol

    PubMed Central

    Santos, Nuno; Santos, Catarina; Valente, Teresa; Gortázar, Christian; Almeida, Virgílio; Correia-Neves, Margarida

    2015-01-01

    Environmental contamination with Mycobacterium tuberculosis complex (MTC) has been considered crucial for bovine tuberculosis persistence in multi-host-pathogen systems. However, MTC contamination has been difficult to detect due to methodological issues. In an attempt to overcome this limitation we developed an improved protocol for the detection of MTC DNA. MTC DNA concentration was estimated by the Most Probable Number (MPN) method. Making use of this protocol we showed that MTC contamination is widespread in different types of environmental samples from the Iberian Peninsula, which supports indirect transmission as a contributing mechanism for the maintenance of bovine tuberculosis in this multi-host-pathogen system. The proportion of MTC DNA positive samples was higher in the bovine tuberculosis-infected than in presumed negative area (0.32 and 0.18, respectively). Detection varied with the type of environmental sample and was more frequent in sediment from dams and less frequent in water also from dams (0.22 and 0.05, respectively). The proportion of MTC-positive samples was significantly higher in spring (p<0.001), but MTC DNA concentration per sample was higher in autumn and lower in summer. The average MTC DNA concentration in positive samples was 0.82 MPN/g (CI95 0.70–0.98 MPN/g). We were further able to amplify a DNA sequence specific of Mycobacterium bovis/caprae in 4 environmental samples from the bTB-infected area. PMID:26561038

  2. HIV-Associated Tuberculosis.

    PubMed

    Naidoo, Kogieleum; Naidoo, Kasavan; Padayatchi, Nesri; Abdool Karim, Quarraisha

    2011-01-01

    The intersecting HIV and Tuberculosis epidemics in countries with a high disease burden of both infections pose many challenges and opportunities. For patients infected with HIV in high TB burden countries, the diagnosis of TB, ARV drug choices in treating HIV-TB coinfected patients, when to initiate ARV treatment in relation to TB treatment, managing immune reconstitution, minimising risk of getting infected with TB and/or managing recurrent TB, minimizing airborne transmission, and infection control are key issues. In addition, given the disproportionate burden of HIV in women in these settings, sexual reproductive health issues and particular high mortality rates associated with TB during pregnancy are important. The scaleup and resource allocation to access antiretroviral treatment in these high HIV and TB settings provide a unique opportunity to strengthen both services and impact positively in meeting Millennium Development Goal 6. PMID:20871843

  3. Tuberculosis: Epidemiology and Control

    PubMed Central

    Sulis, Giorgia; Roggi, Alberto; Matteelli, Alberto; Raviglione, Mario C.

    2014-01-01

    Tuberculosis (TB) is a major public health concern worldwide: despite a regular, although slow, decline in incidence over the last decade, as many as 8.6 million new cases and 1.3 million deaths were estimated to have occurred in 2012. TB is by all means a poverty-related disease, mainly affecting the most vulnerable populations in the poorest countries. The presence of multidrug-resistant strains of M. tuberculosis in most countries, with somewhere prevalence is high, is among the major challenges for TB control, which may hinder recent achievements especially in some settings. Early TB case detection especially in resource-constrained settings and in marginalized groups remains a challenge, and about 3 million people are estimated to remain undiagnosed or not notified and untreated. The World Health Organization (WHO) has recently launched a new global TB strategy for the “post-2015 era” aimed at “ending the global TB epidemic” by 2035. This strategy is based on the three pillars that emphasize patient-centred TB care and prevention, bold policies and supportive systems, and intensified research and innovation. This paper aims to provide an overview of the global TB epidemiology as well as of the main challenges that must be faced to eliminate the disease as a public health problem everywhere. PMID:25408856

  4. Understanding the incremental value of novel diagnostic tests for tuberculosis.

    PubMed

    Arinaminpathy, Nimalan; Dowdy, David

    2015-12-01

    Tuberculosis is a major source of global mortality caused by infection, partly because of a tremendous ongoing burden of undiagnosed disease. Improved diagnostic technology may play an increasingly crucial part in global efforts to end tuberculosis, but the ability of diagnostic tests to curb tuberculosis transmission is dependent on multiple factors, including the time taken by a patient to seek health care, the patient's symptoms, and the patterns of transmission before diagnosis. Novel diagnostic assays for tuberculosis have conventionally been evaluated on the basis of characteristics such as sensitivity and specificity, using assumptions that probably overestimate the impact of diagnostic tests on transmission. We argue for a shift in focus to the evaluation of such tests' incremental value, defining outcomes that reflect each test's purpose (for example, transmissions averted) and comparing systems with the test against those without, in terms of those outcomes. Incremental value can also be measured in units of outcome per incremental unit of resource (for example, money or human capacity). Using a novel, simplified model of tuberculosis transmission that addresses some of the limitations of earlier tuberculosis diagnostic models, we demonstrate that the incremental value of any novel test depends not just on its accuracy, but also on elements such as patient behaviour, tuberculosis natural history and health systems. By integrating these factors into a single unified framework, we advance an approach to the evaluation of new diagnostic tests for tuberculosis that considers the incremental value at the population level and demonstrates how additional data could inform more-effective implementation of tuberculosis diagnostic tests under various conditions. PMID:26633767

  5. Tuberculosis: medico-legal aspects.

    PubMed

    Vetrugno, G; De-Giorgio, F; D'Alessandro, F; Scafetta, I; Berloco, F; Buonsenso, D; Abbate, F; Scalise, G; Pascali, V L; Valentini, P

    2014-01-01

    Tuberculosis is a diffusive infectious disease whose typical behaviour differentiates it from other infectious diseases spread by human-to-human transmission (flu, chicken pox, cholera, etc.) that follow a classic epidemic pattern. Indeed, in the presence of a known source of Koch bacilli that is capable of spreading the bacteria by air, not all exposed individuals inhale the bacteria, not all those who inhale them absorb them, not all those who absorb the bacteria are unable to eliminate them, not all who are able to eliminate them do so using delayed hypersensitivity, not all those who react with delayed hypersensitivity suffer lasting tissue damage (among other things, minor), not all who suffer tissue damage have anatomical sequelae, and not all those who have anatomical sequelae, however minimal, become carriers of bacilli in the latent period. The vast majority (90-95%) of the latter - which are in any case a portion, not the totality of those exposed - remain asymptomatic throughout their lives and never develop active tuberculosis. Based on these biological characteristics and the legal concepts of "epidemic" and "disease," it becomes highly problematic, if not impossible, to assert both that tuberculosis can cause events of sufficient magnitude to be associated with the crime of "epidemic," and that the mere diagnosis of a latent tuberculosis infection is sufficient to assume the presence of an illness legally prosecutable in criminal proceedings or a disability prosecutable in civil proceedings. Furthermore, clinically apparent tuberculosis is a temporarily-and in some cases permanently-disabling condition, and in certain work environments, even with the difficulties caused by the lack of available effective diagnostic tools and the insidious behaviour of the disease in the early stages, targeted monitoring to identify other persons who may become ill is appropriate. PMID:24804006

  6. Tuberculosis: a disease without boundaries.

    PubMed

    Fogel, Nicole

    2015-09-01

    Tuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis (MTB) that usually affects the lungs leading to severe coughing, fever, and chest pains. Although current research in the past four years has provided valuable insight into TB transmission, diagnosis, and treatment, much remains to be discovered to effectively decrease the incidence of and eventually eradicate TB. The disease still puts a strain on public health, being only second to HIV/AIDS in causing high mortality rates. This review will highlight the history of TB as well as provide an overview of the current literature on epidemiology, pathogenesis and the immune response, treatment, and control of TB. In this race to combat a disease that knows no boundaries, it is necessary to have a conceptual and clear understanding of TB overall with the hope of providing better treatment through novel and collaborative research and public health efforts. PMID:26198113

  7. Novel Vaccination Strategies against Tuberculosis

    PubMed Central

    Andersen, Peter; Kaufmann, Stefan H.E.

    2014-01-01

    The tuberculosis (TB) pandemic continues to rampage despite widespread use of the BCG (Bacillus Calmette–Guérin) vaccine. Novel vaccination strategies are urgently needed to arrest global transmission and prevent the uncontrolled development of multidrug-resistant forms of Mycobacterium tuberculosis. Over the last two decades, considerable progress has been made in the field of vaccine development with numerous innovative preclinical candidates and more than a dozen vaccines in clinical trials. These vaccines are developed either as boosters of the current BCG vaccine or as novel prime vaccines to replace BCG. Given the enormous prevalence of latent TB infection, vaccines that are protective on top of an already established infection remain a high priority and a significant scientific challenge. Here we discuss the current state of TB vaccine research and development, our understanding of the underlying immunology, and the requirements for an efficient TB vaccine. PMID:24890836

  8. Detection and Quantification of Mycobacterium tuberculosis in the Sputum of Culture-Negative HIV-infected Pulmonary Tuberculosis Suspects: A Proof-of-Concept Study

    PubMed Central

    Madico, Guillermo; Mpeirwe, Moses; White, Laura; Vinhas, Solange; Orr, Beverley; Orikiriza, Patrick; Miller, Nancy S.; Gaeddert, Mary; Mwanga-Amumpaire, Juliet; Palaci, Moises; Kreiswirth, Barry; Straight, Joe; Dietze, Reynaldo; Boum, Yap; Jones-López, Edward C.

    2016-01-01

    Rationale Rapid diagnosis of pulmonary tuberculosis (TB) is critical for timely initiation of treatment and interruption of transmission. Yet, despite recent advances, many patients remain undiagnosed. Culture, usually considered the most sensitive diagnostic method, is sub-optimal for paucibacillary disease. Methods We evaluated the Totally Optimized PCR (TOP) TB assay, a new molecular test that we hypothesize is more sensitive than culture. After pre-clinical studies, we estimated TOP’s per-patient sensitivity and specificity in a convenience sample of 261 HIV-infected pulmonary TB suspects enrolled into a TB diagnostic study in Mbarara, Uganda against MGIT culture, Xpert MTB/RIF and a composite reference standard. We validated results with a confirmatory PCR used for sequencing M. tuberculosis. Measurements and Results Using culture as reference, TOP had 100% sensitivity but 35% specificity. Against a composite reference standard, the sensitivity of culture (27%) and Xpert MTB/RIF (27%) was lower than TOP (99%), with similar specificity (100%, 98% and 87%, respectively). In unadjusted analyses, culture-negative/TOP-positive patients were more likely to be older (P<0·001), female (P<0·001), have salivary sputum (P = 0·05), sputum smear-negative (P<0.001) and less advanced disease on chest radiograph (P = 0.05). M. tuberculosis genotypes identified in sputum by DNA sequencing exhibit differential growth in culture. Conclusions These findings suggest that the TOP TB assay is accurately detecting M. tuberculosis DNA in the sputum of culture-negative tuberculosis suspects. Our results require prospective validation with clinical outcomes. If the operating characteristics of the TOP assay are confirmed in future studies, it will be justified as a “TB rule out” test. PMID:27391604

  9. Pleural tuberculosis.

    PubMed

    Chakrabarti, B; Davies, P D O

    2006-03-01

    Pleural effusions in tuberculosis are commonly seen in young adults as an immunological phenomenon occurring soon after primary infection. However, the epidemiology and demographics of tuberculous pleurisy are changing due to the impact of HIV co-infection and the increasing number of pleural effusions seen as part of re-activation disease. Pleural biopsy for histology and culture is the mainstay of diagnosis with closed needle biopsy adequate in the majority of cases. Techniques such as PCR of biopsy specimens and the role of pleural fluid ADA are still being evaluated as a diagnostic aid. Tuberculous empyema is less commonly seen in the western world and the diagnostic yield from pleural fluid here is greater than in "primary" effusions. Treatment with appropriate antituberculous chemotherapy is generally successful though there is currently insufficient evidence to recommend the routine use of corticosteroids in this condition. PMID:16700190

  10. Tuberculosis and Diabetes

    MedlinePlus

    TUBERCULOSIS www.who.int/tb & DIABETES THE DUAL EPIDEMIC OF TB AND DIABETES DEADLY LINKAGES  People with ... higher risk of progressing from latent to active tuberculosis.  Diabetes triples a person’s risk of developing TB. ...

  11. Tuberculosis and Pregnancy

    MedlinePlus

    ... Contacts of Persons with Infectious TB Epidemiology of Pediatric Tuberculosis in the United States Targeted Tuberculosis Testing ... and unknown risks of second-line antituberculosis drugs. Breastfeeding Breastfeeding should not be discouraged for women being ...

  12. Effects of Response to 2014–2015 Ebola Outbreak on Deaths from Malaria, HIV/AIDS, and Tuberculosis, West Africa

    PubMed Central

    Parpia, Alyssa S.; Wenzel, Natasha S.; Galvani, Alison P.

    2016-01-01

    Response to the 2014–2015 Ebola outbreak in West Africa overwhelmed the healthcare systems of Guinea, Liberia, and Sierra Leone, reducing access to health services for diagnosis and treatment for the major diseases that are endemic to the region: malaria, HIV/AIDS, and tuberculosis. To estimate the repercussions of the Ebola outbreak on the populations at risk for these diseases, we developed computational models for disease transmission and infection progression. We estimated that a 50% reduction in access to healthcare services during the Ebola outbreak exacerbated malaria, HIV/AIDS, and tuberculosis mortality rates by additional death counts of 6,269 (2,564–12,407) in Guinea; 1,535 (522–2,8780) in Liberia; and 2,819 (844–4,844) in Sierra Leone. The 2014–2015 Ebola outbreak was catastrophic in these countries, and its indirect impact of increasing the mortality rates of other diseases was also substantial. PMID:26886846

  13. Effects of Response to 2014-2015 Ebola Outbreak on Deaths from Malaria, HIV/AIDS, and Tuberculosis, West Africa.

    PubMed

    Parpia, Alyssa S; Ndeffo-Mbah, Martial L; Wenzel, Natasha S; Galvani, Alison P

    2016-03-01

    Response to the 2014-2015 Ebola outbreak in West Africa overwhelmed the healthcare systems of Guinea, Liberia, and Sierra Leone, reducing access to health services for diagnosis and treatment for the major diseases that are endemic to the region: malaria, HIV/AIDS, and tuberculosis. To estimate the repercussions of the Ebola outbreak on the populations at risk for these diseases, we developed computational models for disease transmission and infection progression. We estimated that a 50% reduction in access to healthcare services during the Ebola outbreak exacerbated malaria, HIV/AIDS, and tuberculosis mortality rates by additional death counts of 6,269 (2,564-12,407) in Guinea; 1,535 (522-2,8780) in Liberia; and 2,819 (844-4,844) in Sierra Leone. The 2014-2015 Ebola outbreak was catastrophic in these countries, and its indirect impact of increasing the mortality rates of other diseases was also substantial. PMID:26886846

  14. Natural History of Tuberculosis: Duration and Fatality of Untreated Pulmonary Tuberculosis in HIV Negative Patients: A Systematic Review

    PubMed Central

    Tiemersma, Edine W.; van der Werf, Marieke J.; Borgdorff, Martien W.; Williams, Brian G.; Nagelkerke, Nico J. D.

    2011-01-01

    Background The prognosis, specifically the case fatality and duration, of untreated tuberculosis is important as many patients are not correctly diagnosed and therefore receive inadequate or no treatment. Furthermore, duration and case fatality of tuberculosis are key parameters in interpreting epidemiological data. Methodology and Principal Findings To estimate the duration and case fatality of untreated pulmonary tuberculosis in HIV negative patients we reviewed studies from the pre-chemotherapy era. Untreated smear-positive tuberculosis among HIV negative individuals has a 10-year case fatality variously reported between 53% and 86%, with a weighted mean of 70%. Ten-year case fatality of culture-positive smear-negative tuberculosis was nowhere reported directly but can be indirectly estimated to be approximately 20%. The duration of tuberculosis from onset to cure or death is approximately 3 years and appears to be similar for smear-positive and smear-negative tuberculosis. Conclusions Current models of untreated tuberculosis that assume a total duration of 2 years until self-cure or death underestimate the duration of disease by about one year, but their case fatality estimates of 70% for smear-positive and 20% for culture-positive smear-negative tuberculosis appear to be satisfactory. PMID:21483732

  15. Rigors in tuberculosis.

    PubMed Central

    Harvey, C.; Eykyn, S.; Davidson, C.

    1993-01-01

    Rigors are not a recognized characteristic of miliary tuberculosis. We report two patients presenting with persistent rigors, thought to be suggestive of acute pyogenic infection, who were subsequently found to have miliary tuberculosis. In both cases, there was significant diagnostic delay. Miliary tuberculosis should therefore be included in the differential diagnosis of any patient presenting with unexplained rigors. PMID:8255841

  16. [Lessons learned from tuberculosis outbreak cases].

    PubMed

    Kato, Seiya; Kuwabara, Katsuhiro

    2014-02-01

    Most TB outbreaks were caused by exposure of many people to tuberculosis bacilli due to delayed detection of initial cases who had long-lasting severe coughs and excretion of massive tuberculosis bacilli. They were also affected by several other factors, such as socio-environmental factors of the initial case; time and place of infection; and host factors of the infected persons such as immune status, infectivity, and/or pathogenicity of the bacilli. In this symposium, we learned the seriousness of infection and disease among immune-suppressed groups, special environmental factors with regard to the spread of infection, disease after treatment of latent tuberculosis infection, diagnostic specification of IGRA, and bacteriological features including genotyping of the bacilli. We reaffirmed that countermeasures for the case are important, but outbreaks can provide excellent opportunities to learn important information about infection, disease progression, etc. 1. Tuberculosis outbreak in a cancer ward: Katsuhiro KUWABARA (Division of Respiratory Diseases, National Hospital Organization Nishi-Niigata Chuo National Hospital) There was an outbreak of tuberculosis in a cancer ward of a highly specialized medical center. Outbreak cases included eight hospitalized patients and two medical staff members over a 1.5-year observation period after initial contact. Three immune-compromised patients including the index patent died of cancer and tuberculosis. Community hospitals and highly specialized medical centers, such as cancer centers, should carefully prepare a proper system to prevent nosocomial transmission of tuberculosis. 2. Sixty-one cases of TB exposures in hospital settings and contact investigations of the hospital staff, with special reference to the application of QFT: Hiroko Yoshikawa NIGORIKAWA (The Division of Infectious Diseases, Tokyo Metropolitan Health and Medical Treatment Corporation, Toshima Hospital; present: Division of Infectious Diseases, Tokyo

  17. Tuberculosis verrucosa cutis (TBVC)--foot with miliary tuberculosis.

    PubMed

    Padmavathy, L; Lakshmana Rao, L; Ethirajan, N; Ramakrishna Rao, M; Subrahmanyan, E N; Manohar, U

    2007-07-01

    Tuberculosis Verrucosa Cutis (TBVC) or warty tuberculosis is a variant of cutaneous tuberculosis in patients with good cell mediated immunity (CMI) to Mycobacterium Tuberculosis, while Miliary Tuberculosis is associated with very poor CMI. Two widely different clinical presentations in the same patient are very rare and being reported. PMID:17886704

  18. Estimation of the age-specific per-contact probability of Ebola virus transmission in Liberia using agent-based simulations

    NASA Astrophysics Data System (ADS)

    Siettos, Constantinos I.; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2016-06-01

    Based on multiscale agent-based computations we estimated the per-contact probability of transmission by age of the Ebola virus disease (EVD) that swept through Liberia from May 2014 to March 2015. For the approximation of the epidemic dynamics we have developed a detailed agent-based model with small-world interactions between individuals categorized by age. For the estimation of the structure of the evolving contact network as well as the per-contact transmission probabilities by age group we exploited the so called Equation-Free framework. Model parameters were fitted to official case counts reported by the World Health Organization (WHO) as well as to recently published data of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate.

  19. AIRSLUG: A fortran program for the computation of type curves to estimate transmissivity and storativity from prematurely terminated air-pressurized slug tests

    USGS Publications Warehouse

    Greene, E.A.; Shapiro, A.M.

    1998-01-01

    The Fortran code AIRSLUG can be used to generate the type curves needed to analyze the recovery data from prematurely terminated air-pressurized slug tests. These type curves, when used with a graphical software package, enable the engineer or scientist to analyze field tests to estimate transmissivity and storativity. Prematurely terminating the slug test can significantly reduce the overall time needed to conduct the test, especially at low-permeability sites, thus saving time and money.The Fortran code AIRSLUG can be used to generate the type curves needed to analyze the recovery data from prematurely terminated air-pressurized slug tests. These type curves, when used with a graphical software package, enable the engineer or scientist to analyze field tests to estimate transmissivity and storativity. Prematurely terminating the slug test can significantly reduce the overall time needed to conduct the test, especially at low-permeability sites, thus saving time and money.

  20. Transmission of hepatitis B, hepatitis C and human immunodeficiency viruses through unsafe injections in the developing world: model-based regional estimates.

    PubMed

    Kane, A; Lloyd, J; Zaffran, M; Simonsen, L; Kane, M

    1999-01-01

    Thousands of millions of injections are delivered every year in developing countries, many of them unsafe, and the transmission of certain bloodborne pathogens via this route is thought to be a major public health problem. In this article we report global and regional estimates of the number of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections that may occur from unsafe injections in the developing world. The estimates were determined using quantitative data on unsafe injection practices, transmission efficiency and disease burden of HBV, HCV and HIV and the prevalence of injection use obtained from a review of the literature. A simple mass-action model was used consisting of a generalized linear equation with variables accounting for the prevalence of a pathogen in a population, susceptibility of a population, transmission efficiency of the pathogen, proportion of injections that are unsafe, and the number of injections received. The model was applied to world census data to generate conservative estimates of incidence of transmission of bloodborne pathogens that may be attributable to unsafe injections. The model suggests that approximately 8-16 million HBV, 2.3-4.7 million HCV and 80,000-160,000 HIV infections may result every year from unsafe injections. The estimated range for HBV infections is in accordance with several epidemiological studies that attributed at least 20% of all new HBV infections to unsafe injections in developing countries. Our results suggest that unsafe injections may lead to a high number of infections with bloodborne pathogens. A major initiative is therefore needed to improve injection safety and decrease injection overuse in many countries. PMID:10593027

  1. Drug-resistant tuberculosis--current dilemmas, unanswered questions, challenges, and priority needs.

    PubMed

    Zumla, Alimuddin; Abubakar, Ibrahim; Raviglione, Mario; Hoelscher, Michael; Ditiu, Lucica; McHugh, Timothy D; Squire, S Bertel; Cox, Helen; Ford, Nathan; McNerney, Ruth; Marais, Ben; Grobusch, Martin; Lawn, Stephen D; Migliori, Giovanni-Battista; Mwaba, Peter; O'Grady, Justin; Pletschette, Michel; Ramsay, Andrew; Chakaya, Jeremiah; Schito, Marco; Swaminathan, Soumya; Memish, Ziad; Maeurer, Markus; Atun, Rifat

    2012-05-15

    Tuberculosis was declared a global emergency by the World Health Organization (WHO) in 1993. Following the declaration and the promotion in 1995 of directly observed treatment short course (DOTS), a cost-effective strategy to contain the tuberculosis epidemic, nearly 7 million lives have been saved compared with the pre-DOTS era, high cure rates have been achieved in most countries worldwide, and the global incidence of tuberculosis has been in a slow decline since the early 2000s. However, the emergence and spread of multidrug-resistant (MDR) tuberculosis, extensively drug-resistant (XDR) tuberculosis, and more recently, totally drug-resistant tuberculosis pose a threat to global tuberculosis control. Multidrug-resistant tuberculosis is a man-made problem. Laboratory facilities for drug susceptibility testing are inadequate in most tuberculosis-endemic countries, especially in Africa; thus diagnosis is missed, routine surveillance is not implemented, and the actual numbers of global drug-resistant tuberculosis cases have yet to be estimated. This exposes an ominous situation and reveals an urgent need for commitment by national programs to health system improvement because the response to MDR tuberculosis requires strong health services in general. Multidrug-resistant tuberculosis and XDR tuberculosis greatly complicate patient management within resource-poor national tuberculosis programs, reducing treatment efficacy and increasing the cost of treatment to the extent that it could bankrupt healthcare financing in tuberculosis-endemic areas. Why, despite nearly 20 years of WHO-promoted activity and >12 years of MDR tuberculosis-specific activity, has the country response to the drug-resistant tuberculosis epidemic been so ineffectual? The current dilemmas, unanswered questions, operational issues, challenges, and priority needs for global drug resistance screening and surveillance, improved treatment regimens, and management of outcomes and prevention of DR

  2. [Childhood tuberculosis].

    PubMed

    Hamzaoui, A

    2015-01-01

    Childhood TB is an indication of failing TB control in the community. It allows disease persistence in the population. Mortality and morbidity due to TB is high in children. Moreover, HIV co-infection and multidrug-resistant diseases are as frequent in children as in adults. Infection is more frequent in younger children. Disease risk after primary infection is greatest in infants younger than 2 years. In case of exposure, evidence of infection can be obtained using the tuberculin skin test (TST) or an interferon-gamma assay (IGRA). There is no evidence to support the use of IGRA over TST in young children. TB suspicion should be confirmed whenever possible, using new available tools, particularly in case of pulmonary and lymph node TB. Induced sputum, nasopharyngeal aspiration and fine needle aspiration biopsy provide a rapid and definitive diagnosis of mycobacterial infection in a large proportion of patients. Analysis of paediatric samples revealed higher sensitivity and specificity values of molecular techniques in comparison with the ones originated from adults. Children require higher drugs dosages than adults. Short courses of steroids are associated with TB treatment in case of respiratory distress, bronchoscopic desobstruction is proposed for severe airways involvement and antiretroviral therapy is mandatory in case of HIV infection. Post-exposure prophylaxis in children is a highly effective strategy to reduce the risk of TB disease. The optimal therapy for treatment of latent infection with a presumably multidrug-resistant Mycobacterium tuberculosis strain is currently not known. PMID:24932504

  3. Tuberculosis and nutrition

    PubMed Central

    Gupta, Krishna Bihari; Gupta, Rajesh; Atreja, Atulya; Verma, Manish; Vishvkarma, Suman

    2009-01-01

    Malnutrition and tuberculosis are both problems of considerable magnitude in most of the underdeveloped regions of the world. These two problems tend to interact with each other. Tuberculosis mortality rates in different economic groups in a community tend to vary inversely with their economic levels. Similarly, nutritional status is significantly lower in patients with active tuberculosis compared with healthy controls. Malnutrition can lead to secondary immunodeficiency that increases the host's susceptibility to infection. In patients with tuberculosis, it leads to reduction in appetite, nutrient malabsorption, micronutrient malabsorption, and altered metabolism leading to wasting. Both, protein-energy malnutrition and micronutrients deficiencies increase the risk of tuberculosis. It has been found that malnourished tuberculosis patients have delayed recovery and higher mortality rates than well-nourished patients. Nutritional status of patients improves during tuberculosis chemotherapy. High prevalence of human immunodeficiency (HIV) infection in the underdeveloped countries further aggravates the problem of malnutrition and tuberculosis. Effect of malnutrition on childhood tuberculosis and tuberculin skin test are other important considerations. Nutritional supplementation may represent a novel approach for fast recovery in tuberculosis patients. In addition, raising nutritional status of population may prove to be an effective measure to control tuberculosis in underdeveloped areas of world. PMID:20165588

  4. [Smoking and tuberculosis].

    PubMed

    Underner, Michel; Perriot, Jean

    2012-12-01

    Smoking and tuberculosis represent two major world health issues particularly in developing countries. Tobacco smoke increases risk of Mycobaterium tuberculosis infection by several means: alteration of muco-ciliary clearance, reduced alveolar macrophage activity; immune-depression of pulmonary lymphocytes, reduction of cytotoxic activity of natural killer cells, alteration of the activity of the pulmonary dendritic cells. Both active and passive smoking increases the risk of latent tubercular infection and of pulmonary and extra-pulmonary tuberculosis. Active smoking increases the severity of pulmonary tuberculosis (gravity of radiological lesions). The diagnostic delay and recovery details are more important for smokers. Active smoking increases relapses of both pulmonary and extra-pulmonary tuberculosis after treatment with or without the Directly Observed Treatment Short course (DOTS) with poor observance of treatment. The mortality risk from tuberculosis is heightened among smokers. Smoking cessation represents an essential means of controlling tuberculosis epidemics in developing countries. PMID:22465718

  5. On the use of satellite-based estimates of rainfall temporal distribution to simulate the potential for malaria transmission in rural Africa

    NASA Astrophysics Data System (ADS)

    Yamana, Teresa K.; Eltahir, Elfatih A. B.

    2011-02-01

    This paper describes the use of satellite-based estimates of rainfall to force the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a hydrology-based mechanistic model of malaria transmission. We first examined the temporal resolution of rainfall input required by HYDREMATS. Simulations conducted over Banizoumbou village in Niger showed that for reasonably accurate simulation of mosquito populations, the model requires rainfall data with at least 1 h resolution. We then investigated whether HYDREMATS could be effectively forced by satellite-based estimates of rainfall instead of ground-based observations. The Climate Prediction Center morphing technique (CMORPH) precipitation estimates distributed by the National Oceanic and Atmospheric Administration are available at a 30 min temporal resolution and 8 km spatial resolution. We compared mosquito populations simulated by HYDREMATS when the model is forced by adjusted CMORPH estimates and by ground observations. The results demonstrate that adjusted rainfall estimates from satellites can be used with a mechanistic model to accurately simulate the dynamics of mosquito populations.

  6. Epidemiology of Primary Multidrug-Resistant Tuberculosis, Vladimir Region, Russia.

    PubMed

    Ershova, Julia V; Volchenkov, Grigory V; Kaminski, Dorothy A; Somova, Tatiana R; Kuznetsova, Tatiana A; Kaunetis, Natalia V; Cegielski, J Peter; Kurbatova, Ekaterina V

    2015-11-01

    We studied the epidemiology of drug-resistant tuberculosis (TB) in Vladimir Region, Russia, in 2012. Most cases of multidrug-resistant TB (MDR TB) were caused by transmission of drug-resistant strains, and >33% were in patients referred for testing after mass radiographic screening. Early diagnosis of drug resistance is essential for preventing transmission of MDR TB. PMID:26488585

  7. Protecting health care workers from tuberculosis in China: a review of policy and practice in China and the United States.

    PubMed

    Chai, Shua J; Mattingly, Daniel C; Varma, Jay K

    2013-01-01

    policies based on accumulated evidence and rapidly identifying unsuspected tuberculosis cases, China can develop a more comprehensive strategy to ensure the health of HCWs and reduce transmission of tuberculosis and multidrug-resistant tuberculosis. PMID:22427258

  8. Australia's role in promoting and supporting tuberculosis control in the Western Pacific Region.

    PubMed

    Shaw, Kerrie A

    2013-07-01

    Twenty-one percent of the world's tuberculosis cases are found in the Western Pacific Region. The region has demonstrated a lower rate of decline in incidence than the regions of Africa, the Americas and Europe. Issues around drug resistance, human immunodeficiency virus and diabetes impact on the burden of tuberculosis disease in the Western Pacific Region. Australia has exhibited a low and relatively stable tuberculosis incidence rate but has not progressed toward the desired international goal for tuberculosis elimination (<1 case per million population). The pathogenesis and transmission of tuberculosis make it difficult to achieve elimination within a geographically defined area. These aspects of disease control are amplified by globalisation and Australia's increasing economic and strategic engagement within the Western Pacific Region and South-East Asia. Promoting and supporting tuberculosis control within the Western Pacific Region provides an opportunity for Australia to maintain its low tuberculosis incidence rate and progress toward elimination. PMID:23849030

  9. Tuberculosis Facts - Testing for TB

    MedlinePlus

    Tuberculosis (TB) Facts Testing for TB What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  10. Tuberculosis in the lung (image)

    MedlinePlus

    Tuberculosis is caused by a group of organisms Mycobacterium tuberculosis, M bovis , M africanum and a few other rarer subtypes. Tuberculosis usually appears as a lung (pulmonary) infection. However, ...

  11. Tuberculosis Facts - Exposure to TB

    MedlinePlus

    Tuberculosis (TB) Facts Exposure to TB What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  12. Tuberculosis in the lung (image)

    MedlinePlus

    Tuberculosis is caused by a group of organisms Mycobacterium tuberculosis, M. bovis, M. africanum and a few other rarer subtypes. Tuberculosis usually appears as a lung (pulmonary) infection. However, ...

  13. The Extracellular Matrix Regulates Granuloma Necrosis in Tuberculosis.

    PubMed

    Al Shammari, Basim; Shiomi, Takayuki; Tezera, Liku; Bielecka, Magdalena K; Workman, Victoria; Sathyamoorthy, Tarangini; Mauri, Francesco; Jayasinghe, Suwan N; Robertson, Brian D; D'Armiento, Jeanine; Friedland, Jon S; Elkington, Paul T

    2015-08-01

    A central tenet of tuberculosis pathogenesis is that caseous necrosis leads to extracellular matrix destruction and bacterial transmission. We reconsider the underlying mechanism of tuberculosis pathology and demonstrate that collagen destruction may be a critical initial event, causing caseous necrosis as opposed to resulting from it. In human tuberculosis granulomas, regions of extracellular matrix destruction map to areas of caseous necrosis. In mice, transgenic expression of human matrix metalloproteinase 1 causes caseous necrosis, the pathological hallmark of human tuberculosis. Collagen destruction is the principal pathological difference between humanised mice and wild-type mice with tuberculosis, whereas the release of proinflammatory cytokines does not differ, demonstrating that collagen breakdown may lead to cell death and caseation. To investigate this hypothesis, we developed a 3-dimensional cell culture model of tuberculosis granuloma formation, using bioelectrospray technology. Collagen improved survival of Mycobacterium tuberculosis-infected cells analyzed on the basis of a lactate dehydrogenase release assay, propidium iodide staining, and measurement of the total number of viable cells. Taken together, these findings suggest that collagen destruction is an initial event in tuberculosis immunopathology, leading to caseous necrosis and compromising the immune response, revealing a previously unappreciated role for the extracellular matrix in regulating the host-pathogen interaction. PMID:25676469

  14. Stopping tuberculosis: a biosocial model for sustainable development.

    PubMed

    Ortblad, Katrina F; Salomon, Joshua A; Bärnighausen, Till; Atun, Rifat

    2015-12-01

    Tuberculosis transmission and progression are largely driven by social factors such as poor living conditions and poor nutrition. Increased standards of living and social approaches helped to decrease the burden of tuberculosis before the introduction of chemotherapy in the 1940s. Since then, management of tuberculosis has been largely biomedical. More funding for tuberculosis since 2000, coinciding with the Millennium Development Goals, has yielded progress in tuberculosis mortality but smaller reductions in incidence, which continues to pose a risk to sustainable development, especially in poor and susceptible populations. These at-risk populations need accelerated progress to end tuberculosis as resolved by the World Health Assembly in 2015. Effectively addressing the worldwide tuberculosis burden will need not only enhancement of biomedical approaches but also rebuilding of the social approaches of the past. To combine a biosocial approach, underpinned by social, economic, and environmental actions, with new treatments, new diagnostics, and universal health coverage, will need multisectoral coordination and action involving the health and other governmental sectors, as well as participation of the civil society, and especially the poor and susceptible populations. A biosocial approach to stopping tuberculosis will not only target morbidity and mortality from disease but would also contribute substantially to poverty alleviation and sustainable development that promises to meet the needs of the present, especially the poor, and provide them and subsequent generations an opportunity for a better future. PMID:26515678

  15. Whole-genome sequencing to delineate Mycobacterium tuberculosis outbreaks: a retrospective observational study

    PubMed Central

    Walker, Timothy M; Ip, Camilla LC; Harrell, Ruth H; Evans, Jason T; Kapatai, Georgia; Dedicoat, Martin J; Eyre, David W; Wilson, Daniel J; Hawkey, Peter M; Crook, Derrick W; Parkhill, Julian; Harris, David; Walker, A Sarah; Bowden, Rory; Monk, Philip; Smith, E Grace; Peto, Tim EA

    2013-01-01

    Summary Background Tuberculosis incidence in the UK has risen in the past decade. Disease control depends on epidemiological data, which can be difficult to obtain. Whole-genome sequencing can detect microevolution within Mycobacterium tuberculosis strains. We aimed to estimate the genetic diversity of related M tuberculosis strains in the UK Midlands and to investigate how this measurement might be used to investigate community outbreaks. Methods In a retrospective observational study, we used Illumina technology to sequence M tuberculosis genomes from an archive of frozen cultures. We characterised isolates into four groups: cross-sectional, longitudinal, household, and community. We measured pairwise nucleotide differences within hosts and between hosts in household outbreaks and estimated the rate of change in DNA sequences. We used the findings to interpret network diagrams constructed from 11 community clusters derived from mycobacterial interspersed repetitive-unit–variable-number tandem-repeat data. Findings We sequenced 390 separate isolates from 254 patients, including representatives from all five major lineages of M tuberculosis. The estimated rate of change in DNA sequences was 0·5 single nucleotide polymorphisms (SNPs) per genome per year (95% CI 0·3–0·7) in longitudinal isolates from 30 individuals and 25 families. Divergence is rarely higher than five SNPs in 3 years. 109 (96%) of 114 paired isolates from individuals and households differed by five or fewer SNPs. More than five SNPs separated isolates from none of 69 epidemiologically linked patients, two (15%) of 13 possibly linked patients, and 13 (17%) of 75 epidemiologically unlinked patients (three-way comparison exact p<0·0001). Genetic trees and clinical and epidemiological data suggest that super-spreaders were present in two community clusters. Interpretation Whole-genome sequencing can delineate outbreaks of tuberculosis and allows inference about direction of transmission between

  16. Tuberculosis treatment and management--an update on treatment regimens, trials, new drugs, and adjunct therapies.

    PubMed

    Zumla, Alimuddin; Chakaya, Jeremiah; Centis, Rosella; D'Ambrosio, Lia; Mwaba, Peter; Bates, Matthew; Kapata, Nathan; Nyirenda, Thomas; Chanda, Duncan; Mfinanga, Sayoki; Hoelscher, Michael; Maeurer, Markus; Migliori, Giovanni Battista

    2015-03-01

    WHO estimates that 9 million people developed active tuberculosis in 2013 and 1·5 million people died from it. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis continue to spread worldwide with an estimated 480,000 new cases in 2013. Treatment success rates of MDR and XDR tuberculosis are still low and development of new, more effective tuberculosis drugs and adjunct therapies to improve treatment outcomes are urgently needed. Although standard therapy for drug-sensitive tuberculosis is highly effective, shorter, more effective treatment regimens are needed to reduce the burden of infectious cases. We review the latest WHO guidelines and global recommendations for treatment and management of drug-sensitive and drug-resistant tuberculosis, and provide an update on new drug development, results of several phase 2 and phase 3 tuberculosis treatment trials, and other emerging adjunct therapeutic options for MDR and XDR tuberculosis. The use of fluoroquinolone-containing (moxifloxacin and gatifloxacin) regimens have failed to shorten duration of therapy, and the new tuberculosis drug pipeline is sparse. Scale-up of existing interventions with increased investments into tuberculosis health services, development of new antituberculosis drugs, adjunct therapies and vaccines, coupled with visionary political leadership, are still our best chance to change the unacceptable status quo of the tuberculosis situation worldwide and the growing problem of drug-resistant tuberculosis. PMID:25773212

  17. Tuberculosis in captive Asian elephants (Elephas maximus) in Peninsular Malaysia.

    PubMed

    Ong, B L; Ngeow, Y F; Razak, M F A Abdul; Yakubu, Y; Zakaria, Z; Mutalib, A R; Hassan, L; Ng, H F; Verasahib, K

    2013-07-01

    A cross-sectional study was conducted from 10 January to 9 April 2012, to determine the seroprevalence of tuberculosis (TB) of all captive Asian elephants and their handlers in six locations in Peninsular Malaysia. In addition, trunk-wash samples were examined for tubercle bacillus by culture and polymerase chain reaction (PCR). For 63 elephants and 149 elephant handlers, TB seroprevalence was estimated at 20.4% and 24.8%, respectively. From 151 trunkwash samples, 24 acid-fast isolates were obtained, 23 of which were identified by hsp65-based sequencing as non-tuberculous mycobacteria. The Mycobacterium tuberculosis-specific PCR was positive in the trunk-wash samples from three elephants which were also seropositive. Conversely, the trunk wash from seven seropositive elephants were PCR negative. Hence, there was evidence of active and latent TB in the elephants and the high seroprevalence in the elephants and their handlers suggests frequent, close contact, two-way transmission between animals and humans within confined workplaces. PMID:23414617

  18. Multiple Estimates of Transmissibility for the 2009 Influenza Pandemic Based on Influenza-like-Illness Data from Small US Military Populations

    PubMed Central

    Riley, Pete; Ben-Nun, Michal; Armenta, Richard; Linker, Jon A.; Eick, Angela A.; Sanchez, Jose L.; George, Dylan; Bacon, David P.; Riley, Steven

    2013-01-01

    Rapidly characterizing the amplitude and variability in transmissibility of novel human influenza strains as they emerge is a key public health priority. However, comparison of early estimates of the basic reproduction number during the 2009 pandemic were challenging because of inconsistent data sources and methods. Here, we define and analyze influenza-like-illness (ILI) case data from 2009–2010 for the 50 largest spatially distinct US military installations (military population defined by zip code, MPZ). We used publicly available data from non-military sources to show that patterns of ILI incidence in many of these MPZs closely followed the pattern of their enclosing civilian population. After characterizing the broad patterns of incidence (e.g. single-peak, double-peak), we defined a parsimonious SIR-like model with two possible values for intrinsic transmissibility across three epochs. We fitted the parameters of this model to data from all 50 MPZs, finding them to be reasonably well clustered with a median (mean) value of 1.39 (1.57) and standard deviation of 0.41. An increasing temporal trend in transmissibility (, p-value: 0.013) during the period of our study was robust to the removal of high transmissibility outliers and to the removal of the smaller 20 MPZs. Our results demonstrate the utility of rapidly available – and consistent – data from multiple populations. PMID:23696723

  19. A tuberculosis nationwide prevalence survey in Gambia, 2012

    PubMed Central

    Kendall, Lindsay; Bashorun, Adedapo; Linda, Christopher; Omoleke, Semeeh; Jeffries, David; Maane, Rahmatulai; Alorse, Beatrice Dei; Alorse, William Dei; Okoi, Catherine Bi; Mlaga, Kodjovi D; Kinteh, Ma Ansu; Donkor, Simon; de Jong, Bouke C; Antonio, Martin; d’Alessandro, Umberto

    2016-01-01

    Abstract Objective To estimate the population prevalence of active pulmonary tuberculosis in Gambia. Methods Between December 2011 and January 2013, people aged ≥ 15 years participating in a nationwide, multistage cluster survey were screened for active pulmonary tuberculosis with chest radiography and for tuberculosis symptoms. For diagnostic confirmation, sputum samples were collected from those whose screening were positive and subjected to fluorescence microscopy and liquid tuberculosis cultures. Multiple imputation and inverse probability weighting were used to estimate tuberculosis prevalence. Findings Of 100 678 people enumerated, 55 832 were eligible to participate and 43 100 (77.2%) of those participated. A majority of participants (42 942; 99.6%) were successfully screened for symptoms and by chest X-ray. Only 5948 (13.8%) were eligible for sputum examination, yielding 43 bacteriologically confirmed, 28 definite smear-positive and six probable smear-positive tuberculosis cases. Chest X-ray identified more tuberculosis cases (58/69) than did symptoms alone (43/71). The estimated prevalence of smear-positive and bacteriologically confirmed pulmonary tuberculosis were 90 (95% confidence interval, CI: 53–127) and 212 (95% CI: 152–272) per 100 000 population, respectively. Tuberculosis prevalence was higher in males (333; 95% CI: 233–433) and in the 35–54 year age group (355; 95% CI: 219–490). Conclusion The burden of tuberculosis remains high in Gambia but lower than earlier estimates of 490 per 100 000 population in 2010. Less than half of all cases would have been identified based on smear microscopy results alone. Successful control efforts will require interventions targeting men, increased access to radiography and more accurate, rapid diagnostic tests. PMID:27274595

  20. Defect detection and size estimation in billet from profile of time-of-flight using ultrasonic transmission method with linear scanning

    NASA Astrophysics Data System (ADS)

    Miyamoto, Ryusuke; Mizutani, Koichi; Ebihara, Tadashi; Wakatsuki, Naoto

    2015-07-01

    In this study, defect detection and size estimation in billet by transmission method with linear scanning were carried out and the validity of the method was evaluated by numerical simulation. In addition, the suitable signal frequency and aperture of transducers were clarified. As a result, the following were found: a defect can be detected, signals with frequencies lower than those generally used in conventional ultrasonic testing (i.e., 0.5-1.5 MHz) are desirable, and the time-of-flight (TOF) deviation Δτ becomes largest when the wavelength at center frequency and the aperture of transducers are comparable. Defect size can be estimated when a single defect exists alone and the defect is not near the surface of a billet. Although defect size estimation becomes difficult when the defect is near the surface of a billet, the defect can be detected by our proposed method.

  1. Estimating the Impact of Earlier ART Initiation and Increased Testing Coverage on HIV Transmission among Men Who Have Sex with Men in Mexico using a Mathematical Model

    PubMed Central

    Caro-Vega, Yanink; del Rio, Carlos; Dias Lima, Viviane; Lopez-Cervantes, Malaquias; Crabtree-Ramirez, Brenda; Bautista-Arredondo, Sergio; Colchero, M. Arantxa; Sierra-Madero, Juan

    2015-01-01

    Objective To estimate the impact of late ART initiation on HIV transmission among men who have sex with men (MSM) in Mexico. Methods An HIV transmission model was built to estimate the number of infections transmitted by HIV-infected men who have sex with men (MSM-HIV+) MSM-HIV+ in the short and long term. Sexual risk behavior data were estimated from a nationwide study of MSM. CD4+ counts at ART initiation from a representative national cohort were used to estimate time since infection. Number of MSM-HIV+ on treatment and suppressed were estimated from surveillance and government reports. Status quo scenario (SQ), and scenarios of early ART initiation and increased HIV testing were modeled. Results We estimated 14239 new HIV infections per year from MSM-HIV+ in Mexico. In SQ, MSM take an average 7.4 years since infection to initiate treatment with a median CD4+ count of 148 cells/mm3(25th-75th percentiles 52–266). In SQ, 68% of MSM-HIV+ are not aware of their HIV status and transmit 78% of new infections. Increasing the CD4+ count at ART initiation to 350 cells/mm3 shortened the time since infection to 2.8 years. Increasing HIV testing to cover 80% of undiagnosed MSM resulted in a reduction of 70% in new infections in 20 years. Initiating ART at 500 cells/mm3 and increasing HIV testing the reduction would be of 75% in 20 years. Conclusion A substantial number of new HIV infections in Mexico are transmitted by undiagnosed and untreated MSM-HIV+. An aggressive increase in HIV testing coverage and initiating ART at a CD4 count of 500 cells/mm3 in this population would significantly benefit individuals and decrease the number of new HIV infections in Mexico. PMID:26302044

  2. Development of a Laboratory Synchrophasor Network and an Application to Estimate Transmission Line Parameters in Real Time

    NASA Astrophysics Data System (ADS)

    Almiron Bonnin, Rubens Eduardo

    The development of an experimental synchrophasors network and application of synchrophasors for real-time transmission line parameter monitoring are presented in this thesis. In the laboratory setup, a power system is simulated in a RTDS real-time digital simulator, and the simulated voltages and currents are input to hardware phasor measurement units (PMUs) through the analog outputs of the simulator. Time synchronizing signals for the PMU devices are supplied from a common GPS clock. The real time data collected from PMUs are sent to a phasor data concentrator (PDC) through Ethernet using the TCP/IP protocol. A real-time transmission line parameter monitoring application program that uses the synchrophasor data provided by the PDC is implemented and validated. The experimental synchrophasor network developed in this thesis is expected to be used in research on synchrophasor applications as well as in graduate and undergraduate teaching.

  3. Genotype heterogeneity of Mycobacterium tuberculosis within geospatial hotspots suggests foci of imported infection in Sydney, Australia.

    PubMed

    Gurjav, Ulziijargal; Jelfs, Peter; Hill-Cawthorne, Grant A; Marais, Ben J; Sintchenko, Vitali

    2016-06-01

    In recent years the State of New South Wales (NSW), Australia, has maintained a low tuberculosis incidence rate with little evidence of local transmission. Nearly 90% of notified tuberculosis cases occurred in people born in tuberculosis-endemic countries. We analyzed geographic, epidemiological and genotypic data of all culture-confirmed tuberculosis cases to identify the bacterial and demographic determinants of tuberculosis hotspot areas in NSW. Standard 24-loci mycobacterium interspersed repetitive unit-variable number tandem repeat (MIRU-24) typing was performed on all isolates recovered between 2009 and 2013. In total 1692/1841 (91.9%) cases with confirmed Mycobacterium tuberculosis infection had complete MIRU-24 and demographic data and were included in the study. Despite some year-to-year variability, spatio-temporal analysis identified four tuberculosis hotspots. The incidence rate and the relative risk of tuberculosis in these hotspots were 2- to 10-fold and 4- to 8-fold higher than the state average, respectively. MIRU-24 profiles of M. tuberculosis isolates associated with these hotspots revealed high levels of heterogeneity. This suggests that these spatio-temporal hotspots, within this low incidence setting, can represent areas of predominantly imported infection rather than clusters of cases due to local transmission. These findings provide important epidemiological insight and demonstrate the value of combining tuberculosis genotyping and spatiotemporal data to guide better-targeted public health interventions. PMID:26187743

  4. [Pharyngeal tuberculosis: Case report].

    PubMed

    Spini, Roxana Gabriela; Bordino, Lucas; Cohen, Daniela; Martins, Andrea; Ramírez, Zaida; González, Norma E

    2015-08-01

    Pharyngeal tuberculosis is a rare extrapulmonary manifestation. In Argentina, the number of cases of tuberculosis reported in children under 19 years in 2012 was 1752. Only 12.15% had extrapulmonary manifestation. A case of a 17 year old girl with pharyngeal tuberculosis is reported. The patient presented intermittent fever and swallowing pain for 6 months, without response to conventional antibiotic treatment. Chest X-ray showedbilateral micronodular infiltrate, so hospitalization was decided to study and treat. The sputum examination for acid-fast resistant bacilli was positive and treatment with four antituberculous drugs was started, with good evolution and disappearance of symptoms. Diagnostic confirmation with the isolation of Mycobacterium tuberculosis in sputum culture was obtained. The main symptoms of pharyngeal tuberculosis are sore throat and difficulty in swallowing of long evolution. It is important to consider tuberculosis as differential diagnosis in patients with chronic pharyngitis unresponsive to conventional treatment. PMID:26172025

  5. [Hospital detention in tuberculosis control].

    PubMed

    Villalbí, Joan R; Rodríguez-Campos, Mònica; Orcau, Àngels; Espachs, M Àngels; Salamero, Marta; Maldonado, José; Caylà, Joan A

    2016-01-01

    This article describes the actions of public health services of the city of Barcelona to prevent tuberculosis transmission by noncompliant smear-positive patients by using the possibilities of Spanish Law 3/1986. The actions were based on a resolution of the health authorities on the need to locate such patients and to detain them in hospitals to provide treatment. This involved police cooperation, informing noncompliant patients, and requesting ratification from the Administrative Court. The article describes the process and the characteristics of the cases involved. Over nine years, from July 2006 to June 2015, the law was used in only twelve cases. The authors conclude that the criteria of prudence and proportionality were used in the application of the law, which resulted in the treatment of patients who posed a risk to their environment, reducing the transmission of infection. PMID:26832855

  6. Endobronchial Tuberculosis Mimicking Asthma

    PubMed Central

    Argun Baris, Serap; Onyilmaz, Tuğba; Basyigit, Ilknur; Boyaci, Hasim

    2015-01-01

    Endobronchial tuberculosis (EBTB) is defined as tuberculosis infection of the tracheobronchial tree with microbial and histopathological evidence. The clinical symptoms of the diseases are nonspecific. Chronic cough is the major symptom of the disease. The diagnosis is often delayed due to its nonspecific presentation and misdiagnosed as bronchial asthma. This case is presented to recall the notion that the endobronchial tuberculosis can mimic asthma and the importance of bronchoscopic evaluation in a patient with chronic cough and treatment resistant asthma. PMID:26798513

  7. TUBERCULOSIS COMO ENFERMEDAD OCUPACIONAL

    PubMed Central

    Mendoza-Ticona, Alberto

    2014-01-01

    Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis en el lugar de trabajo, se revisan las evidencias para declarar a la tuberculosis como enfermedad ocupacional en trabajadores de salud y se presenta la legislación peruana vigente al respecto. PMID:22858771

  8. Risk Factors for Tuberculosis

    PubMed Central

    Narasimhan, Padmanesan; Wood, James; MacIntyre, Chandini Raina; Mathai, Dilip

    2013-01-01

    The risk of progression from exposure to the tuberculosis bacilli to the development of active disease is a two-stage process governed by both exogenous and endogenous risk factors. Exogenous factors play a key role in accentuating the progression from exposure to infection among which the bacillary load in the sputum and the proximity of an individual to an infectious TB case are key factors. Similarly endogenous factors lead in progression from infection to active TB disease. Along with well-established risk factors (such as human immunodeficiency virus (HIV), malnutrition, and young age), emerging variables such as diabetes, indoor air pollution, alcohol, use of immunosuppressive drugs, and tobacco smoke play a significant role at both the individual and population level. Socioeconomic and behavioral factors are also shown to increase the susceptibility to infection. Specific groups such as health care workers and indigenous population are also at an increased risk of TB infection and disease. This paper summarizes these factors along with health system issues such as the effects of delay in diagnosis of TB in the transmission of the bacilli. PMID:23476764

  9. Tuberculosis in Pregnancy

    PubMed Central

    Apuzzio, Joseph J.

    1996-01-01

    Tuberculosis (TB) during pregnancy and in the perinatal period was once considered to be an infrequent event in the United States. After a decade of steady decline, however, the disease has begun a resurgence. According to the CDC, a 20% increase in the number of reported cases occurred between 1985 and 1992. The factors associated with this increase are the emergence of human immunodeficiency virus (HIV) infection, the development of drug-resistant organisms, substance abuse, homelessness, and immigration. Environmental factors promoting transmission can be found in overcrowded areas such as correctional facilities, nursing homes, hospitals, and migrant-worker camps. For a large number of medically underserved women, the obstetrician is the only interface with medical care, as most of these patients do not have primary-care providers. It is important, therefore, that health-care providers recognize the clinical symptoms of TB and follow the recognized guidelines for antenatal screening for TB because the omission of these steps can lead to potentially disastrous sequelae in the fetus and neonate. PMID:18476074

  10. High-resolution typing by integration of genome sequencing data in a large tuberculosis cluster.

    PubMed

    Schürch, Anita C; Kremer, Kristin; Daviena, Olaf; Kiers, Albert; Boeree, Martin J; Siezen, Roland J; van Soolingen, Dick

    2010-09-01

    To investigate whether genome sequencing yields more useful markers than those currently used to study the epidemiology of tuberculosis, it was applied to three Mycobacterium tuberculosis isolates of the Harlingen outbreak. Our findings suggest that single nucleotide polymorphisms can be used to identify transmission chains in restriction fragment length polymorphism clusters. PMID:20592143

  11. High-Resolution Typing by Integration of Genome Sequencing Data in a Large Tuberculosis Cluster▿

    PubMed Central

    Schürch, Anita C.; Kremer, Kristin; Daviena, Olaf; Kiers, Albert; Boeree, Martin J.; Siezen, Roland J.; van Soolingen, Dick

    2010-01-01

    To investigate whether genome sequencing yields more useful markers than those currently used to study the epidemiology of tuberculosis, it was applied to three Mycobacterium tuberculosis isolates of the Harlingen outbreak. Our findings suggest that single nucleotide polymorphisms can be used to identify transmission chains in restriction fragment length polymorphism clusters. PMID:20592143

  12. Modeling epidemics of multidrug-resistant M. tuberculosis of heterogeneous fitness.

    PubMed

    Cohen, Ted; Murray, Megan

    2004-10-01

    Mathematical models have recently been used to predict the future burden of multidrug-resistant tuberculosis (MDRTB). These models suggest the threat of multidrug resistance to TB control will depend on the relative 'fitness' of MDR strains and imply that if the average fitness of MDR strains is considerably less than that of drug-sensitive strains, the emergence of resistance will not jeopardize the success of tuberculosis control efforts. Multidrug resistance in M. tuberculosis is conferred by the sequential acquisition of a number of different single-locus mutations that have been shown to have heterogeneous phenotypic effects. Here we model the impact of initial fitness estimates on the emergence of MDRTB assuming that the relative fitness of MDR strains is heterogeneous. We find that even when the average relative fitness of MDR strains is low and a well-functioning control program is in place, a small subpopulation of a relatively fit MDR strain may eventually outcompete both the drug-sensitive strains and the less fit MDR strains. These results imply that current epidemiological measures and short-term trends in the burden of MDRTB do not provide evidence that MDRTB strains can be contained in the absence of specific efforts to limit transmission from those with MDR disease. PMID:15378056

  13. Modeling Tuberculosis Dynamics, Detection and Control in Cattle Herds

    PubMed Central

    Bekara, Mohammed El Amine; Courcoul, Aurélie; Bénet, Jean-Jacques; Durand, Benoit

    2014-01-01

    Epidemiological models are key tools for designing and evaluating detection and control strategies against animal infectious diseases. In France, after decades of decrease of bovine tuberculosis (bTB) incidence, the disease keeps circulating. Increasing prevalence levels are observed in several areas, where the detection and control strategy could be adapted. The objective of this work was to design and calibrate a model of the within-herd transmission of bTB. The proposed model is a stochastic model operating in discrete-time. Three health states were distinguished: susceptible, latent and infected. Dairy and beef herd dynamics and bTB detection and control programs were explicitly represented. Approximate Bayesian computation was used to estimate three model parameters from field data: the transmission parameter when animals are inside (βinside) and outside (βoutside) buildings, and the duration of the latent phase. An independent dataset was used for model validation. The estimated median was 0.43 [0.16–0.84] month−1 for βinside and 0.08 [0.01–0.32] month−1 for βoutside. The median duration of the latent period was estimated 3.5 [2]–[8] months. The sensitivity analysis showed only minor influences of fixed parameter values on these posterior estimates. Validation based on an independent dataset showed that in more than 80% of herds, the observed proportion of animals with detected lesions was between the 2.5% and 97.5% percentiles of the simulated distribution. In the absence of control program and once bTB has become enzootic within a herd, the median effective reproductive ratio was estimated to be 2.2 in beef herds and 1.7 in dairy herds. These low estimates are consistent with field observations of a low prevalence level in French bTB-infected herds. PMID:25254369

  14. Mycobacterium tuberculosis: Manipulator of Protective Immunity

    PubMed Central

    Korb, Vanessa C.; Chuturgoon, Anil A.; Moodley, Devapregasan

    2016-01-01

    Mycobacterium tuberculosis (MTB) is one of the most successful pathogens in human history and remains a global health challenge. MTB has evolved a plethora of strategies to evade the immune response sufficiently to survive within the macrophage in a bacterial-immunological equilibrium, yet causes sufficient immunopathology to facilitate its transmission. This review highlights MTB as the driver of disease pathogenesis and presents evidence of the mechanisms by which MTB manipulates the protective immune response into a pathological productive infection. PMID:26927066

  15. Infection Control for Drug-Resistant Tuberculosis: Early Diagnosis and Treatment Is the Key.

    PubMed

    van Cutsem, Gilles; Isaakidis, Petros; Farley, Jason; Nardell, Ed; Volchenkov, Grigory; Cox, Helen

    2016-05-15

    Multidrug-resistant (MDR) tuberculosis, "Ebola with wings," is a significant threat to tuberculosis control efforts. Previous prevailing views that resistance was mainly acquired through poor treatment led to decades of focus on drug-sensitive rather than drug-resistant (DR) tuberculosis, driven by the World Health Organization's directly observed therapy, short course strategy. The paradigm has shifted toward recognition that most DR tuberculosis is transmitted and that there is a need for increased efforts to control DR tuberculosis. Yet most people with DR tuberculosis are untested and untreated, driving transmission in the community and in health systems in high-burden settings. The risk of nosocomial transmission is high for patients and staff alike. Lowering transmission risk for MDR tuberculosis requires a combination approach centered on rapid identification of active tuberculosis disease and tuberculosis drug resistance, followed by rapid initiation of appropriate treatment and adherence support, complemented by universal tuberculosis infection control measures in healthcare facilities. It also requires a second paradigm shift, from the classic infection control hierarchy to a novel, decentralized approach across the continuum from early diagnosis and treatment to community awareness and support. A massive scale-up of rapid diagnosis and treatment is necessary to control the MDR tuberculosis epidemic. This will not be possible without intense efforts toward the implementation of decentralized, ambulatory models of care. Increasing political will and resources need to be accompanied by a paradigm shift. Instead of focusing on diagnosed cases, recognition that transmission is driven largely by undiagnosed, untreated cases, both in the community and in healthcare settings, is necessary. This article discusses this comprehensive approach, strategies available, and associated challenges. PMID:27118853

  16. Novel approaches in diagnosing tuberculosis

    NASA Astrophysics Data System (ADS)

    Kolk, Arend H. J.; Dang, Ngoc A.; Kuijper, Sjoukje; Gibson, Tim; Anthony, Richard; Claassens, Mareli M.; Kaal, Erwin; Janssen, Hans-Gerd

    2011-06-01

    The WHO declared tuberculosis (TB) a global emergency. An estimated 8-9 million new cases occur each year with 2-3 million deaths. Currently, TB is diagnosed mostly by chest-X ray and staining of the mycobacteria in sputum with a detection limit of 1x104 bacteria /ml. There is an urgent need for better diagnostic tools for TB especially for developing countries. We have validated the electronic nose from TD Technology for the detection of Mycobacterium tuberculosis by headspace analysis of 284 sputum samples from TB patients. We used linear discriminant function analysis resulting in a sensitivity of 75% a specificity of 67% and an accuracy of 69%. Further research is still required to improve the results by choosing more selective sensors and sampling techniques. We used a fast gas chromatography- mass spectrometry method (GC-MS). The automated procedure is based on the injection of sputum samples which are methylated inside the GC injector using thermally assisted hydrolysis and methylation (THM-GC-MS). Hexacosanoic acid in combination with tuberculostearic acid was found to be specific for the presence of M. tuberculosis. The detection limit was similar to microscopy. We found no false positives, all microscopy and culture positive samples were also found positive with the THM-GC-MS method. The detection of ribosomal RNA from the infecting organism offers great potential since rRNA molecules outnumber chromosomal DNA by a factor 1000. It thus may possible to detect the organism without amplification of the nucleic acids (NA). We used a capture and a tagged detector probe for the direct detection of M. tuberculosis in sputum. So far the detection limit is 1x106 bacteria / ml. Currently we are testing a Lab-On-A-Chip Interferometer detection system.

  17. Tuberculosis lymphadenitis in Ethiopia.

    PubMed

    Biadglegne, Fantahun; Tesfaye, Weghata; Anagaw, Belay; Tessema, Belay; Debebe, Tewodrose; Anagaw, Berhanu; Mulu, Andargachew; Sack, Ulrich; Rodloff, Arne C

    2013-01-01

    Tuberculosis (TB) is one of the most serious public health challenges in Ethiopia. Indeed, Ethiopia ranks 7th among 22 countries with a high burden of TB worldwide. Both pulmonary TB and extrapulmonary TB (EPTB) are issues of concern. Ethiopia ranks 3rd in terms of the number of EPTB patients worldwide, with TB lymphadenitis (TBL) being the most common. According to the World Health Organization's Global TB Report 2009, the estimated number of TB patients in Ethiopia was 314,267 in 2007, with an estimated incidence rate of 378 patients per 100,000 population. Furthermore, 36% patients suffered from EPTB, with TBL accounting for 80% of these patients. In Ethiopia, pathological services, culture, and drug susceptibility testing for mycobacterium species are not available as routine tests, not even for cases with suspected infection by drug-resistant strains. Therefore, the management of multidrug-resistant (MDR) TB in Ethiopia is currently unsatisfactory. Against this background, a high index of clinical doubt and timely use of diagnostic methods, prompt confirmation of diagnosis, and early initiation of specific anti-TB treatment are the key factors for the successful management of MDR-TB and TBL in Ethiopia. PMID:23883834

  18. [Multifocal tuberculosis in immunocompetent patients].

    PubMed

    Rezgui, Amel; Fredj, Fatma Ben; Mzabi, Anis; Karmani, Monia; Laouani, Chadia

    2016-01-01

    Multifocal tuberculosis is defined as the presence of lesions affecting at least two extrapulmonary sites, with or without pulmonary involvement. This retrospective study of 10 cases aims to investigate the clinical and evolutionary characteristics of multifocal tuberculosis. It included 41 cases with tuberculosis collected between 1999 and 2013. Ten patients had multifocal tuberculosis (24%): 9 women and 1 man, the average age was 50 years (30-68 years). Our patients were correctly BCG vaccinated. The evaluation of immunodepression was negative in all patients. 7 cases had lymph node tuberculosis, 3 cases digestive tuberculosis, 2 cases pericardial tuberculosis, 2 cases osteoarticular tuberculosis, 1 case brain tuberculosis, 2 cases urinary tuberculosis, 4 cases urogenital tuberculosis, 1 case adrenal tuberculosis, 1 case cutaneous and 1 case muscle tuberculosis. All patients received anti-tuberculosis treatment for a mean duration of 10 months, with good evolution. Multifocal tuberculosis is difficult to diagnose. It can affect immunocompetent patients but often has good prognosis. Anti-tuberculosis therapy must be initiated as soon as possible to avoid sequelae. PMID:27583077

  19. Pulmonary Paragonimiasis Mimicking Tuberculosis.

    PubMed

    Prasad, Kj; Basu, Arup; Khana, Shilpi; Wattal, Chand

    2015-08-01

    Paragonimiasis is a disease which is frequently misdiagnosed as pulmonary tuberculosis. In the areas where people eat crab/crayfish this disease should be considered in the differential diagnosis to avoid antituberculosis treatment for a non-tubercular condition. We are reporting a case of pulmonary paragonimiasis who had been treated for tuberculosis. PMID:27604443

  20. "Tuberculosis Case Management" Training.

    ERIC Educational Resources Information Center

    Knebel, Elisa; Kolodner, Jennifer

    2001-01-01

    The need to isolated health providers with critical knowledge in tuberculosis (TB) case management prompted the development of "Tuberculosis Case Management" CD-ROM. Features include "Learning Center,""Examination Room," and "Library." The combination of audio, video, and graphics allows participants to practice acquired skills in a simulated…

  1. A New Sparse Adaptive Channel Estimation Method Based on Compressive Sensing for FBMC/OQAM Transmission Network

    PubMed Central

    Wang, Han; Du, Wencai; Xu, Lingwei

    2016-01-01

    The conventional channel estimation methods based on a preamble for filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) systems in mobile-to-mobile sensor networks are inefficient. By utilizing the intrinsicsparsity of wireless channels, channel estimation is researched as a compressive sensing (CS) problem to improve the estimation performance. In this paper, an AdaptiveRegularized Compressive Sampling Matching Pursuit (ARCoSaMP) algorithm is proposed. Unlike anterior greedy algorithms, the new algorithm can achieve the accuracy of reconstruction by choosing the support set adaptively, and exploiting the regularization process, which realizes the second selecting of atoms in the support set although the sparsity of the channel is unknown. Simulation results show that CS-based methods obtain significant channel estimation performance improvement compared to that of conventional preamble-based methods. The proposed ARCoSaMP algorithm outperforms the conventional sparse adaptive matching pursuit (SAMP) algorithm. ARCoSaMP provides even more interesting results than the mostadvanced greedy compressive sampling matching pursuit (CoSaMP) algorithm without a prior sparse knowledge of the channel. PMID:27347967

  2. A New Sparse Adaptive Channel Estimation Method Based on Compressive Sensing for FBMC/OQAM Transmission Network.

    PubMed

    Wang, Han; Du, Wencai; Xu, Lingwei

    2016-01-01

    The conventional channel estimation methods based on a preamble for filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) systems in mobile-to-mobile sensor networks are inefficient. By utilizing the intrinsicsparsity of wireless channels, channel estimation is researched as a compressive sensing (CS) problem to improve the estimation performance. In this paper, an AdaptiveRegularized Compressive Sampling Matching Pursuit (ARCoSaMP) algorithm is proposed. Unlike anterior greedy algorithms, the new algorithm can achieve the accuracy of reconstruction by choosing the support set adaptively, and exploiting the regularization process, which realizes the second selecting of atoms in the support set although the sparsity of the channel is unknown. Simulation results show that CS-based methods obtain significant channel estimation performance improvement compared to that of conventional preamble-based methods. The proposed ARCoSaMP algorithm outperforms the conventional sparse adaptive matching pursuit (SAMP) algorithm. ARCoSaMP provides even more interesting results than the mostadvanced greedy compressive sampling matching pursuit (CoSaMP) algorithm without a prior sparse knowledge of the channel. PMID:27347967

  3. Model approaches for estimating the influence of time-varying socio-environmental factors on macroparasite transmission in two endemic regions

    PubMed Central

    ZHONG, BO; CARLTON, ELIZABETH J.; SPEAR, ROBERT C.

    2009-01-01

    The environmental determinants of vector- and host-borne diseases include time-varying components that modify key transmission parameters, resulting in transient couplings between environmental phenomena and transmission processes. While some time-varying drivers are periodic in nature, some are aperiodic, such as those that involve episodic events or complex patterns of human behavior. Understanding these couplings can allow for prediction of periods of peak infection risk, and ultimately presents opportunities for optimizing intervention selection and timing. Schistosome macroparasites of humans exhibit multiple free-living stages as well as intermediate hosts, and are thus model organisms for illustrating the influence of environmental forcing on transmission. Time-varying environmental factors, termed gating functions, for schistosomes include larval response to temperature and rainfall, seasonal water contact patterns and snail population dynamics driven by weather variables. The biological bases for these modifiers are reviewed, and their values are estimated and incorporated into a transmission model that simulates a multi-year period in two schistosomiasis endemic regions. Modeling results combined with a scale dependent correlation analysis indicate the end effect of these site-specific gating functions is to strongly govern worm burden in these communities, in a manner particularly sensitive to the hydrological differences between sites. Two classes of gating functions were identified, those that act in concert to modify human infection (and determine worm acquisition late in the season), and those that act on snail infection (and determine early season worm acquisition). The importance of these factors for control programs and surveillance is discussed. PMID:20454601

  4. How well can we estimate areal-averaged spectral surface albedo from ground-based transmission in the Atlantic coastal area?

    NASA Astrophysics Data System (ADS)

    Kassianov, Evgueni; Barnard, James; Flynn, Connor; Riihimaki, Laura; Marinovici, Cristina

    2015-10-01

    Areal-averaged albedos are particularly difficult to measure in coastal regions, because the surface is not homogenous, consisting of a sharp demarcation between land and water. With this difficulty in mind, we evaluate a simple retrieval of areal-averaged surface albedo using ground-based measurements of atmospheric transmission alone under fully overcast conditions. To illustrate the performance of our retrieval, we find the areal-averaged albedo using measurements from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) at five wavelengths (415, 500, 615, 673, and 870 nm). These MFRSR data are collected at a coastal site in Graciosa Island, Azores supported by the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Program. The areal-averaged albedos obtained from the MFRSR are compared with collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS) whitesky albedo at four nominal wavelengths (470, 560, 670 and 860 nm). These comparisons are made during a 19-month period (June 2009 - December 2010). We also calculate composite-based spectral values of surface albedo by a weighted-average approach using estimated fractions of major surface types observed in an area surrounding this coastal site. Taken as a whole, these three methods of finding albedo show spectral and temporal similarities, and suggest that our simple, transmission-based technique holds promise, but with estimated errors of about ±0.03. Additional work is needed to reduce this uncertainty in areas with inhomogeneous surfaces.

  5. How Well Can We Estimate Areal-Averaged Spectral Surface Albedo from Ground-Based Transmission in an Atlantic Coastal Area?

    SciTech Connect

    Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Riihimaki, Laura D.; Marinovici, Maria C.

    2015-10-15

    Areal-averaged albedos are particularly difficult to measure in coastal regions, because the surface is not homogenous, consisting of a sharp demarcation between land and water. With this difficulty in mind, we evaluate a simple retrieval of areal-averaged surface albedo using ground-based measurements of atmospheric transmission alone under fully overcast conditions. To illustrate the performance of our retrieval, we find the areal-averaged albedo using measurements from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) at five wavelengths (415, 500, 615, 673, and 870 nm). These MFRSR data are collected at a coastal site in Graciosa Island, Azores supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program. The areal-averaged albedos obtained from the MFRSR are compared with collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS) white-sky albedo at four nominal wavelengths (470, 560, 670 and 860 nm). These comparisons are made during a 19-month period (June 2009 - December 2010). We also calculate composite-based spectral values of surface albedo by a weighted-average approach using estimated fractions of major surface types observed in an area surrounding this coastal site. Taken as a whole, these three methods of finding albedo show spectral and temporal similarities, and suggest that our simple, transmission-based technique holds promise, but with estimated errors of about ±0.03. Additional work is needed to reduce this uncertainty in areas with inhomogeneous surfaces.

  6. Psychiatry and Tuberculosis

    PubMed Central

    Fantl, Kurt

    1950-01-01

    Studies on the psychosomatic aspects of tuberculosis have not brought to light a clearcut correlation between a specific personality structure and susceptibility to the illness. The recommendation is made to look for several rather than for one personality type. It is suggested that people should be studied who react to stress with loss of appetite and loss of sleep. This character structure in contrast to that where the person withdraws into sleep and overeats might make a person prone to tuberculosis. The somatopsychic influence of tuberculosis needs to be interpreted in terms of the localization of the lesion as well as infectiousness and conspicuousness of the disease. Some common sociopsychological factors of tuberculosis have been mentioned. Reports on mental illness and tuberculosis and on diet were reviewed. PMID:14792351

  7. The contribution of badgers to confirmed tuberculosis in cattle in high-incidence areas in England.

    PubMed

    Donnelly, Christl A; Nouvellet, Pierre

    2013-01-01

    The role of badgers in the transmission and maintenance of bovine tuberculosis (TB) in British cattle is widely debated as part of the wider discussions on whether badger culling and/or badger vaccination should play a role in the government's strategy to eradicate cattle TB. The key source of information on the contribution from badgers within high-cattle-TB-incidence areas of England is the Randomised Badger Culling Trial (RBCT), with two analyses providing estimates of the average overall contribution of badgers to confirmed cattle TB in these areas. A dynamical model characterizing the association between the estimated prevalence of Mycobacterium bovis (the causative agent of bovine TB) among badgers culled in the initial RBCT proactive culls and the incidence among sympatric cattle herds prior to culling is used to estimate the average overall contribution of badgers to confirmed TB herd breakdowns among proactively culled areas. The resulting estimate based on all data (52%) has considerable uncertainty (bootstrap 95% confidence interval (CI): 9.1-100%). Separate analyses of experimental data indicated that the largest estimated reduction in confirmed cattle TB achieved inside the proactive culling areas was 54% (overdispersion-adjusted 95% CI: 38-66%), providing a lower bound for the average overall contribution of badgers to confirmed cattle TB. Thus, taking into account both results, the best estimate of the average overall contribution of badgers is roughly half, with 38% being a robustly estimated lower bound. However, the dynamical model also suggested that only 5.7% (bootstrap 95% CI: 0.9-25%) of the transmission to cattle herds is badger-to-cattle with the remainder of the average overall contribution from badgers being in the form of onward cattle-to-cattle transmission. These estimates, confirming that badgers do play a role in bovine TB transmission, inform debate even if they do not point to a single way forward. PMID:24761309

  8. Associations between national tuberculosis program budgets and tuberculosis outcomes: an ecological study

    PubMed Central

    Chapple, Will; Katz, Alan Roy; Li, Dongmei

    2012-01-01

    Introduction The objective of this study is to explore the associations between national tuberculosis program (NTP) budget allocation and tuberculosis related outcomes in the World Health Organization's 22 high burden countries from 2007–2009. Methods This ecological study used mixed effects and generalized estimating equation models to identify independent associations between NTP budget allocations and various tuberculosis related outcomes. Models were adjusted for a number of independent variables previously noted to be associated with tuberculosis incidence. Results Increasing the percent of the NTP budget for advocacy, communication and social mobilization was associated with an increase in the case detection rate. Increasing TB-HIV funding was associated with an increase in HIV testing among TB patients. Increasing the percent of the population covered by the Directly Observed Therapy (DOT) program was associated with an increase in drug susceptibility testing. Laboratory funding was positively associated with tuberculosis notification. Increasing the budgets for first line drugs, management and multi-drug resistant tuberculosis (MDR-TB) was associated with a decrease in smear positive deaths. Conclusion Effective TB control is a complex and multifaceted challenge. This study revealed a number of budget allocation related factors associated with improved TB outcome parameters. If confirmed with future longitudinal studies, these findings could help guide NTP managers with allocation decisions. PMID:23024825

  9. An outbreak of multidrug-resistant tuberculosis among a family.

    PubMed

    Iliaz, Sinem; Caglar, Emel; Koksalan, Orhan Kaya; Chousein, Efsun Gonca Ugur

    2016-04-01

    Tuberculosis is a major public health problem and it may be complicated by multidrug-resistant tuberculosis (MDR-TB). Wide transmission among immunocompetent contacts of the index case is possible. If you detect tuberculosis in two contacts of the index case, it is called an outbreak. The aim of our paper is to evaluate the characteristics of a MDR-TB outbreak affecting 7 people in a family treated during 2012-2014 in Istanbul Yedikule Training and Research Hospital for Chest Disease and Thoracic Surgery, Turkey. The cultures, spoligotyping, and DNA fingerprinting revealed the same Mycobacterium tuberculosis species as T1 genotype and ST53 subtype. All patients were negative for human immunodeficiency virus and free of other underlying diseases. PMID:27451825

  10. Bovine tuberculosis and badgers in Britain: relevance of the past.

    PubMed

    Atkins, P J; Robinson, P A

    2013-07-01

    The European badger (Meles meles) has been identified as a wildlife reservoir of bovine tuberculosis and a source of transmission to cattle in Britain and Ireland. Both behavioural ecology and statistical ecological modelling have indicated the long-term persistence of the disease in some badger communities, and this is postulated to account for the high incidence of bovine tuberculosis in cattle across large tracts of England and Wales. This paper questions this consensus by using historical cartographic evidence to show that tuberculosis in cattle had a very different spatial distribution before 1960 to the present day. Since few of the badgers collected in road traffic accidents between 1972 and 1990 had tuberculosis in counties such as Cheshire, where the disease had until shortly before that been rife in the cattle population, the role of badgers as reservoirs in spreading disease in similar counties outside the south-west of England has to be questioned. PMID:23347609

  11. Driving the Way to Tuberculosis Elimination: The Essential Role of Fundamental Research.

    PubMed

    Lienhardt, Christian; Kraigsley, Alison M; Sizemore, Christine F

    2016-08-01

    Tuberculosis has impacted human health for millennia. The World Health Organization estimated that, in 2014, 9.6 million people developed tuberculosis and 1.5 million people died from the disease. In May 2014, the World Health Assembly endorsed the new "End TB Strategy" that presents a pathway to tuberculosis elimination. The strategy outlines 3 areas of emphasis, one of which is intensified research and innovation. In this article we highlight the essential role for fundamental tuberculosis research in the future of tuberculosis diagnostics, treatment, and prevention. To maximize the impact of fundamental research, we must foster collaboration among all stakeholders engaged in tuberculosis research and control to facilitate open dialogue to assure that critical gaps in outcome-oriented science are identified and addressed. We present here a framework for future discussions among scientists, physicians, research and development specialists, and public health managers for the reinforcement of national and international strategies toward tuberculosis elimination. PMID:27270671

  12. Pulmonary Disease due to Mycobacterium tuberculosis in a Horse: Zoonotic Concerns and Limitations of Antemortem Testing

    PubMed Central

    Lyashchenko, Konstantin P.; Greenwald, Rena; Esfandiari, Javan; Lecu, Alexis; Waters, W. Ray; Posthaus, Horst; Bodmer, Thomas; Janssens, Jean-Paul; Aloisio, Fabio; Graubner, Claudia; Grosclaude, Eléonore; Piersigilli, Alessandra; Schiller, Irene

    2012-01-01

    A case of pulmonary tuberculosis caused by Mycobacterium tuberculosis was diagnosed in a horse. Clinical evaluation performed prior to euthanasia did not suggest tuberculosis, but postmortem examination provided pathological and bacteriological evidence of mycobacteriosis. In the lungs, multiple tuberculoid granulomas communicating with the bronchiolar lumen, pleural effusion, and a granulomatous lymphadenitis involving mediastinal and tracheobronchial lymph nodes were found. Serologic response to M. tuberculosis antigens was detected in the infected horse, but not in the group of 42 potentially exposed animals (18 horses, 14 alpacas, 6 donkeys, and 4 dogs) which showed no signs of disease. Diagnosis of tuberculosis in live horses remains extremely difficult. Four of 20 animal handlers at the farm were positive for tuberculous infection upon follow-up testing by interferon-gamma release assay, indicating a possibility of interspecies transmission of M. tuberculosis. PMID:22567544

  13. Pulmonary Disease due to Mycobacterium tuberculosis in a Horse: Zoonotic Concerns and Limitations of Antemortem Testing.

    PubMed

    Lyashchenko, Konstantin P; Greenwald, Rena; Esfandiari, Javan; Lecu, Alexis; Waters, W Ray; Posthaus, Horst; Bodmer, Thomas; Janssens, Jean-Paul; Aloisio, Fabio; Graubner, Claudia; Grosclaude, Eléonore; Piersigilli, Alessandra; Schiller, Irene

    2012-01-01

    A case of pulmonary tuberculosis caused by Mycobacterium tuberculosis was diagnosed in a horse. Clinical evaluation performed prior to euthanasia did not suggest tuberculosis, but postmortem examination provided pathological and bacteriological evidence of mycobacteriosis. In the lungs, multiple tuberculoid granulomas communicating with the bronchiolar lumen, pleural effusion, and a granulomatous lymphadenitis involving mediastinal and tracheobronchial lymph nodes were found. Serologic response to M. tuberculosis antigens was detected in the infected horse, but not in the group of 42 potentially exposed animals (18 horses, 14 alpacas, 6 donkeys, and 4 dogs) which showed no signs of disease. Diagnosis of tuberculosis in live horses remains extremely difficult. Four of 20 animal handlers at the farm were positive for tuberculous infection upon follow-up testing by interferon-gamma release assay, indicating a possibility of interspecies transmission of M. tuberculosis. PMID:22567544

  14. Mycobacterium tuberculosis isolates from single outpatient clinic in Panama City exhibit wide genetic diversity.

    PubMed

    Sambrano, Dilcia; Correa, Ricardo; Almengor, Pedro; Domínguez, Amada; Vega, Silvio; Goodridge, Amador

    2014-08-01

    Understanding Mycobacterium tuberculosis biodiversity and transmission is significant for tuberculosis control. This short report aimed to determine the genetic diversity of M. tuberculosis isolates from an outpatient clinic in Panama City. A total of 62 M. tuberculosis isolates were genotyped by 12 loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) and Spoligotyping. Forty-five (72.6%) of the isolates showed unique MIRU-VNTR genotypes, and 13 (21%) of the isolates were grouped into four clusters. Four isolates showed polyclonal MIRU-VNTR genotypes. The MIRU-VNTR Hunter-Gaston discriminatory index reached 0.988. The Spoligotyping analysis revealed 16 M. tuberculosis families, including Latin American-Mediterranean, Harlem, and Beijing. These findings suggest a wide genetic diversity of M. tuberculosis isolates at one outpatient clinic. A detailed molecular epidemiology survey is now warranted, especially following second massive immigration for local Panama Canal expansion activities. PMID:24865686

  15. AIDS and multidrug-resistant tuberculosis: an epidemic transforms an old disease.

    PubMed

    Farley, T A

    1992-08-01

    Since 1985, tuberculosis case counts in the United States have increased, primarily because of the influence of the HIV epidemic. In addition, during this time outbreaks of multidrug-resistant tuberculosis among patients with AIDS or HIV infection have been reported in New York City and Florida. These outbreaks have occurred in hospitals and prisons and have been characterized by high case fatality rates, disease transmission within the institutions, and high infection rates in health care workers. The increase in tuberculosis rates and the outbreaks have raised concern that multidrug-resistant tuberculosis could become a widespread problem in the United States. Dealing with tuberculosis in the 1990s will require reconsideration of our current methods of tuberculosis prevention, diagnosis, treatment, and control. PMID:1453093

  16. Empirical Estimation of R0 for Unknown Transmission Functions: The Case of Chronic Wasting Disease in Alberta.

    PubMed

    Potapov, Alex; Merrill, Evelyn; Pybus, Margo; Lewis, Mark A

    2015-01-01

    We consider the problem of estimating the basic reproduction number R0 from data on prevalence dynamics at the beginning of a disease outbreak. We derive discrete and continuous time models, some coefficients of which are to be fitted from data. We show that prevalence of the disease is sufficient to determine R0. We apply this method to chronic wasting disease spread in Alberta determining a range of possible R0 and their sensitivity to the probability of deer annual survival. PMID:26452231

  17. The return of tuberculosis.

    PubMed

    Fätkenheuer, G; Taelman, H; Lepage, P; Schwenk, A; Wenzel, R

    1999-06-01

    At the end of the 20th century, tuberculosis remains a major public health issue. In developing countries tuberculosis is a leading cause of morbidity and mortality, and the spread of the HIV epidemic contributes significantly to the worsening of the situation. Coinfection with tuberculosis and HIV results in special diagnostic and therapeutic problems and uses up larger amounts of medical resources in developing countries. Outbreaks of multidrug resistant tuberculosis (MDR-TB) were first reported from US-American centers caring for HIV patients, but have now been observed in many other countries. In Western Europe the tuberculosis epidemic is under control, but increasing incidence rates in migrants raise new problems in these countries. Tuberculosis is uncontrolled in large parts of the former Soviet Union due to the socio-economic break-down in these countries. Only rigorous infection control measures on a world-wide scale will prevent further detoriation of this situation. Therefore, the extension of surveillance systems, and sufficient funding for the prevention, diagnosis, and treatment of tuberculosis by national governments and international organizations are all urgently needed. PMID:10354864

  18. Perspectives on tuberculosis in pregnancy.

    PubMed

    Bates, Matthew; Ahmed, Yusuf; Kapata, Nathan; Maeurer, Markus; Mwaba, Peter; Zumla, Alimuddin

    2015-03-01

    Tuberculosis (TB) has been recognized as an important cause of morbidity and mortality in pregnancy for nearly a century, but research and efforts to roll out comprehensive TB screening and treatment in high-risk populations such as those with a high prevalence of HIV or other diseases of poverty, have lagged behind similar efforts to address HIV infection in pregnancy and the prevention of mother-to-child-transmission. Immunological changes during pregnancy make the activation of latent TB infection or de novo infection more likely than among non-pregnant women. TB treatment in pregnancy poses several problems that have been under-researched, such as contraindications to anti-TB and anti-HIV drugs and potential risks to the neonate, which are particularly important with respect to second-line TB treatment. Whilst congenital TB is thought to be rare, data from high HIV burden settings suggest this is not the case. There is a need for more studies screening for TB in neonates and observing outcomes, and testing preventative or curative actions. National tuberculosis control programmes (NTPs) should work with antenatal and national HIV programmes in high-burden populations to provide screening at antenatal clinics, or to establish functioning systems whereby pregnant women at high risk can drop in to routine NTP screening stations. PMID:25809768

  19. Tuberculosis: distribution, risk factors, mortality.

    PubMed

    Kochi, A

    1994-10-01

    About a century after Koch's discovery of the TB bacilli the tuberculosis epidemic which had appeared to be under control was again recognized as a major global health threat. The decline in the epidemic in this century had been largely through the improved living standards and, eventually, the availability and use of effective antibiotics. While tuberculosis gradually disappeared from the health agenda in the western world it remained a big killer throughout the century and in 1992 an estimated 2.7 million TB deaths occurred; 30 million will die from TB during the 1990s if current trends are not reversed. The annual number of new cases will increase from 7.5 million estimated in 1990 to more than 10 million in the year 2000. The main factors for this increase are demographic forces, population movements, the HIV epidemic and increasing drug resistance. The impact of the HIV epidemic is already felt in many sub-Saharan African countries and now threatens Asia where almost two-thirds of the world's TB infected population live and where HIV is spreading. Tuberculosis has also reemerged as a major public health problem in industrialized countries due to international migration, the breakdown of health services, including TB services etc. The control of the epidemic can only be through a concerted action to reinstate TB as priority among health concerns, reflected in national and international resources. A coalition of public and private supporters must be mobilized to support the effort to fight the disease. Governments, non-governmental organizations, the business community, refugee organizations, medical institutions, and other UN agencies are invited to join with WHO in this effort. PMID:7713546

  20. Utilizing Nontraditional Data Sources for Near Real-Time Estimation of Transmission Dynamics During the 2015-2016 Colombian Zika Virus Disease Outbreak

    PubMed Central

    Santillana, Mauricio; Mekaru, Sumiko R; McGinnis, Denise P; Khan, Kamran; Brownstein, John S

    2016-01-01

    Background Approximately 40 countries in Central and South America have experienced local vector-born transmission of Zika virus, resulting in nearly 300,000 total reported cases of Zika virus disease to date. Of the cases that have sought care thus far in the region, more than 70,000 have been reported out of Colombia. Objective In this paper, we use nontraditional digital disease surveillance data via HealthMap and Google Trends to develop near real-time estimates for the basic (R0) and observed (Robs) reproductive numbers associated with Zika virus disease in Colombia. We then validate our results against traditional health care-based disease surveillance data. Methods Cumulative reported case counts of Zika virus disease in Colombia were acquired via the HealthMap digital disease surveillance system. Linear smoothing was conducted to adjust the shape of the HealthMap cumulative case curve using Google search data. Traditional surveillance data on Zika virus disease were obtained from weekly Instituto Nacional de Salud (INS) epidemiological bulletin publications. The Incidence Decay and Exponential Adjustment (IDEA) model was used to estimate R0 and Robs for both data sources. Results Using the digital (smoothed HealthMap) data, we estimated a mean R0 of 2.56 (range 1.42-3.83) and a mean Robs of 1.80 (range 1.42-2.30). The traditional (INS) data yielded a mean R0 of 4.82 (range 2.34-8.32) and a mean Robs of 2.34 (range 1.60-3.31). Conclusions Although modeling using the traditional (INS) data yielded higher R0 estimates than the digital (smoothed HealthMap) data, modeled ranges for Robs were comparable across both data sources. As a result, the narrow range of possible case projections generated by the traditional (INS) data was largely encompassed by the wider range produced by the digital (smoothed HealthMap) data. Thus, in the absence of traditional surveillance data, digital surveillance data can yield similar estimates for key transmission parameters and

  1. New tuberculosis vaccines.

    PubMed

    Martín Montañés, Carlos; Gicquel, Brigitte

    2011-03-01

    The current tuberculosis (TB) vaccine, bacille Calmette-Guerin (BCG), is a live vaccine used worldwide, as it protects against severe forms of the disease, saving thousands of lives every year, but its efficacy against pulmonary forms of TB, responsible for transmission of the diseases, is variable. For more than 80 years now no new TB vaccines have been successfully developed. Over the last decade the effort of the scientific community has resulted in the design and construction of promising vaccine candidates. The goal is to develop a new generation of vaccines effective against respiratory forms of the disease. We will focus this review on new prophylactic vaccine candidates that aim to prevent TB diseases. Two are the main strategies used to improve the immunity conferred by the current BCG vaccine, by boosting it with new subunit vaccines, and a second strategy is focused on the construction of new more effective live vaccines, capable to replace the current BCG and to be used as prime vaccines. After rigorous preclinical studies in different animal models new TB vaccine candidates enter in clinical trials in humans. First, a small Phase I for safety followed by immunological evaluation in Phase II trials and finally evaluated in large population Phase III efficacy trials in endemic countries. At present BCG prime and boost with different subunit vaccine candidates are the more advanced assessed in Phase II. Two prime vaccines (based on recombinant BCG) have been successfully evaluated for safety in Phase I trials. A short number of live attenuated vaccines are in advance preclinical studies and the candidates ready to enter Phase I safety trials are produced under current good manufacturing practices. PMID:21420568

  2. Urinary tuberculosis: modern issues.

    PubMed

    Wise, Gilbert J

    2009-07-01

    Tuberculosis remains an epidemic that affects one third of the world's population. The persistence of this disease is caused by a large pool of immune-compromised and lower socioeconomic populations. The advent of rapid transportation and migration has contributed to the persistence of this disease in developed and less developed nations. The emergence of drug-resistant strains has added an additional factor for the pervasiveness of tuberculosis. The genitourinary system is a primary target for hematogenous infections. This paper reviews the contemporary issues that affect the diagnosis and treatment of urinary tuberculosis. PMID:19570494

  3. Phase noise tolerance study in coherent optical circular QAM transmissions with Viterbi-Viterbi carrier phase estimation.

    PubMed

    Zafra, Sebastian Ortega; Pang, Xiaodan; Jacobsen, Gunnar; Popov, Sergei; Sergeyev, Sergey

    2014-12-15

    We present a performance evaluation of a non-conventional approach to implement phase noise tolerant optical systems with multilevel modulation formats. The performance of normalized Viterbi-Viterbi carrier phase estimation (V-V CPE) is investigated in detail for circular m-level quadrature amplitude modulation (C-mQAM) signals. The intrinsic property of C-mQAM constellation points with a uniform phase separation allows a straightforward employment of V-V CPE without the need to adapt constellation. Compared with conventional feed-forward CPE for square QAM signals, the simulated results show an enhanced tolerance of linewidth symbol duration product (ΔνTs) at a low sensitivity penalty by using feed-forward CPE structure with C-mQAM. This scheme can be easily upgraded to higher order modulations without inducing considerable complexity. PMID:25607005

  4. Low level nitrogen laser therapy in pulmonary tuberculosis

    PubMed Central

    Bhatia, C.C.; Sharma, N.; Hemvani, N.; Chitnis, D.S.

    2015-01-01

    Background and aims: WHO estimated 9 million new Tuberculosis cases and 1.5 million TB deaths in 2013. Globally 480000 Multi drug resistant tuberculosis cases were noted and majority of them were in India, China and Russian federation. Multi drug resistant tuberculosis cases are difficult to treat and have high mortality. Presently, it was aimed to assess prevalence of drug resistance in M. tuberculosis isolates in Central India, to check the in-vitro effect of N2 Laser on M. tuberculosis and to study the therapeutic effect of intra cavitary N2 laser on pulmonary Tuberculosis cases not responding to chemotherapy. Materials and methods: Drug sensitivity testing was carried out on 567 isolates of M. tuberculosis by proportion method. To check the effect of N2 laser on M. tuberculosis, suspension spread on LJ plate and part of the plate exposed to N2 laser for 10 min and plate incubated for 4 weeks to see the effect. For exposure to lung cavity a needle was introduced into the lung through which fiber was passed to the cavity for N2 laser irradiation for 10 min. Results: Only 12.8% isolates of M. tuberculosis were sensitive to all anti-Tubercular drugs and 21.5% were found to be resistant to Rifampicin qualifying definition of Multi drug resistant tuberculosis. Bactericidal effect for N2 laser was seen in-vitro on exposure to N2 laser. Clinical improvement occurred in 90% of the 96 patients; 60% of the patients showed improvement on their X-rays and 75% turned out to be Acid fast bacilli smear negative in 4 to 15 days. Conclusions: Intra-cavitory N2 laser therapy was found to have remarkable success as an adjunct to chemotherapy. PMID:26557736

  5. Waveform-based simulated annealing of crosshole transmission data: a semi-global method for estimating seismic anisotropy

    NASA Astrophysics Data System (ADS)

    Afanasiev, Michael V.; Pratt, R. Gerhard; Kamei, Rie; McDowell, Glenn

    2014-12-01

    We successfully apply the semi-global inverse method of simulated annealing to determine the best-fitting 1-D anisotropy model for use in acoustic frequency domain waveform tomography. Our forward problem is based on a numerical solution of the frequency domain acoustic wave equation, and we minimize wavefield phase residuals through random perturbations to a 1-D vertically varying anisotropy profile. Both real and synthetic examples are presented in order to demonstrate and validate the approach. For the real data example, we processed and inverted a cross-borehole data set acquired by Vale Technology Development (Canada) Ltd. in the Eastern Deeps deposit, located in Voisey's Bay, Labrador, Canada. The inversion workflow comprises the full suite of acquisition, data processing, starting model building through traveltime tomography, simulated annealing and finally waveform tomography. Waveform tomography is a high resolution method that requires an accurate starting model. A cycle-skipping issue observed in our initial starting model was hypothesized to be due to an erroneous anisotropy model from traveltime tomography. This motivated the use of simulated annealing as a semi-global method for anisotropy estimation. We initially tested the simulated annealing approach on a synthetic data set based on the Voisey's Bay environment; these tests were successful and led to the application of the simulated annealing approach to the real data set. Similar behaviour was observed in the anisotropy models obtained through traveltime tomography in both the real and synthetic data sets, where simulated annealing produced an anisotropy model which solved the cycle-skipping issue. In the real data example, simulated annealing led to a final model that compares well with the velocities independently estimated from borehole logs. By comparing the calculated ray paths and wave paths, we attributed the failure of anisotropic traveltime tomography to the breakdown of the ray

  6. Estimation of Effective Transmission Loss Due to Subtropical Hydrometeor Scatters using a 3D Rain Cell Model for Centimeter and Millimeter Wave Applications

    NASA Astrophysics Data System (ADS)

    Ojo, J. S.; Owolawi, P. A.

    2014-12-01

    The problem of hydrometeor scattering on microwave radio communication down links continues to be of interest as the number of the ground and earth space terminals continually grows The interference resulting from the hydrometeor scattering usually leads to the reduction in the signal-to-noise ratio ( SNR) at the affected terminal and at worst can even end up in total link outage. In this paper, an attempt has been made to compute the effective transmission loss due to subtropical hydrometeors on vertically polarized signals in Earth-satellite propagation paths in the Ku, Ka and V band frequencies based on the modified Capsoni 3D rain cell model. The 3D rain cell model has been adopted and modified using the subtropical log-normal distributions of raindrop sizes and introducing the equivalent path length through rain in the estimation of the attenuation instead of the usual specific attenuation in order to account for the attenuation of both wanted and unwanted paths to the receiver. The co-channels, interference at the same frequency is very prone to the higher amount of unwanted signal at the elevation considered. The importance of joint transmission is also considered.

  7. Tuberculosis in the 1990s.

    PubMed

    Bass, J B

    1995-02-01

    The steady decline in tuberculosis case rate reversed in the mid-1980s, and tuberculosis cases have increased dramatically since that time. Important factors contributing to this increase are the human immunodeficiency virus (HIV) epidemic and tuberculosis occurring in foreign-born persons. Tuberculosis outbreaks have occurred in HIV clinics and wards, prisons, homeless shelters, nursing homes, and health care facilities. Some of the outbreaks have involved strains of tuberculosis resistant to multiple antituberculosis drugs. Recent recommendations for initial therapy of tuberculosis include the use of four drugs and directly observed therapy in an effort to prevent the emergence of further drug resistance. PMID:7771659

  8. Tuberculosis in tropical Africa

    PubMed Central

    Roelsgaard, E.; Iversen, E.; Bløcher, C.

    1964-01-01

    Up to the end of the nineteenth century the tubercle bacillus apparently had little opportunity of disseminating among the rather isolated tribes of tropical Africa. With the creation of large centres of trade and industry in the wake of European colonization, tuberculosis seems to have spread rapidly over the continent and is today found everywhere. In a number of tuberculosis prevalence surveys conducted by WHO during 1955-60, randomly selected population groups were tuberculin tested, X-rayed and had sputa examined by direct microscopy. The three methods of examination were applied independently of one another. Data collected during the surveys have been analysed with a view to discovering common epidemiological features of tuberculosis in tropical Africa, assessing the reliability of the diagnostic methods employed and discussing their usefulness in future tuberculosis control programmes. PMID:14178027

  9. Tuberculosis Data and Statistics

    MedlinePlus

    ... Organization Chart Advisory Groups Federal TB Task Force Data and Statistics Language: English Español (Spanish) Recommend on ... United States publication. PDF [6 MB] Interactive TB Data Tool Online Tuberculosis Information System (OTIS) OTIS is ...

  10. Update on cutaneous tuberculosis*

    PubMed Central

    Dias, Maria Fernanda Reis Gavazzoni; Bernardes Filho, Fred; Quaresma, Maria Victória; do Nascimento, Leninha Valério; Nery, José Augusto da Costa; Azulay, David Rubem

    2014-01-01

    Tuberculosis continues to draw special attention from health care professionals and society in general. Cutaneous tuberculosis is an infection caused by M. tuberculosis complex, M. bovis and bacillus Calmette-Guérin. Depending on individual immunity, environmental factors and the type of inoculum, it may present varied clinical and evolutionary aspects. Patients with HIV and those using immunobiological drugs are more prone to infection, which is a great concern in centers where the disease is considered endemic. This paper aims to review the current situation of cutaneous tuberculosis in light of this new scenario, highlighting the emergence of new and more specific methods of diagnosis, and the molecular and cellular mechanisms that regulate the parasite-host interaction. PMID:25387498

  11. On the source-frequency dependence of fracture-orientation estimates from shear-wave transmission experiments

    NASA Astrophysics Data System (ADS)

    Santos, Leo K.; de Figueiredo, J. J. S.; Omoboya, Bode; Schleicher, Jörg; Stewart, Robert R.; Dyaur, Nikolay

    2015-03-01

    Shear-wave propagation through anisotropic fractured or cracked media can provide valuable information about these fracture swarms and their orientations. The main goal of this work is to recover information about fracture orientation based on the shear waveforms (S-waveforms). For this study, we carried out ultrasonic S-wave measurements in a synthetic physical model made of epoxy resin (isotropic matrix proxy), with small cylindrical rubber strips as inclusions (artificial cracks) inserted in it to simulate a homogeneous anisotropic medium. In these experiments, we used low, intermediate, and high frequency shear-wave sources, with frequencies 90, 431, and 840 kHz. We integrated and interpreted the resulting S-wave seismograms, cross-correlation panels and anisotropic parameter-analysis curves. We were able to estimate the crack orientation in single-orientation fracture zones. The high frequency peaks associated with scattered S-waves provided interpretable information about the fracture orientations when the propagation direction was parallel to the fracture plane. The analysis was possible utilizing results from frequency-versus-polarization-angle curves. Moreover, we applied a bandpass filtering process to the intermediate and high frequency seismograms in order to obtain low frequency seismograms. A spectral analysis using frequency-wavenumber (F-K) spectra supports this filtering process. The results obtained using an analysis of cross-correlograms and the Thomsen parameter γ extracted from filtered high-frequency data were quite similar to those obtained using a low-frequency source. This highlighted the possibility of using less expensive high-frequency sources to recover information about the fracture set.

  12. [Mammary tuberculosis: two cases].

    PubMed

    Hafidi, M R; Kouach, J; Hamidi, L A; Achenani, M; Benchakroun, K; Salek, G; Zoubir, Y; Moussaoui, R D; Dehayni, M

    2011-01-01

    Tuberculosis of the breast is a very rare infection, it occurs chiefly in women of childbearing potential, usually as an apparently primary infection and constitute a diagnosis and therapeutic challenge. Administration of antituberculous agents is the mainstay of therapy. Surgery is required in some cases. We report two cases of breast tuberculosis. The diagnosis was put on histology with good outcome under anti bacillary treatment. Through the literature data we recall the epidemiological, clinical, diagnostic and treatment of this pathology. PMID:22765979

  13. Tuberculosis in Children

    PubMed Central

    Marais, Ben J.; Schaaf, H. Simon

    2014-01-01

    Many clinicians regard tuberculosis as an adult pulmonary disease, but tuberculosis (TB) is a major cause of disease, both pulmonary and extrapulmonary, and death in young children from TB-endemic countries, especially in areas affected by poverty, social disruption, and human immunodeficiency virus (HIV) infection. This article reviews the disease burden and the natural history of disease in children with TB. It also provides guidance regarding the diagnosis, treatment, and prevention of TB in children. PMID:25037105

  14. Tuberculosis in children.

    PubMed

    Marais, Ben J; Schaaf, H Simon

    2014-09-01

    Many clinicians regard tuberculosis as an adult pulmonary disease, but tuberculosis (TB) is a major cause of disease, both pulmonary and extrapulmonary, and death in young children from TB-endemic countries, especially in areas affected by poverty, social disruption, and human immunodeficiency virus (HIV) infection. This article reviews the disease burden and the natural history of disease in children with TB. It also provides guidance regarding the diagnosis, treatment, and prevention of TB in children. PMID:25037105

  15. Consequences of genomic diversity in Mycobacterium tuberculosis.

    PubMed

    Coscolla, Mireia; Gagneux, Sebastien

    2014-12-01

    The causative agent of human tuberculosis, Mycobacterium tuberculosis complex (MTBC), comprises seven phylogenetically distinct lineages associated with different geographical regions. Here we review the latest findings on the nature and amount of genomic diversity within and between MTBC lineages. We then review recent evidence for the effect of this genomic diversity on mycobacterial phenotypes measured experimentally and in clinical settings. We conclude that overall, the most geographically widespread Lineage 2 (includes Beijing) and Lineage 4 (also known as Euro-American) are more virulent than other lineages that are more geographically restricted. This increased virulence is associated with delayed or reduced pro-inflammatory host immune responses, greater severity of disease, and enhanced transmission. Future work should focus on the interaction between MTBC and human genetic diversity, as well as on the environmental factors that modulate these interactions. PMID:25453224

  16. Airborne Fiber Size Characterization in Exposure Estimation: Evaluation of a Modified Transmission Electron Microcopy Protocol for Asbestos and Potential Use for Carbon Nanotubes and Nanofibers

    PubMed Central

    Dement, John M.; Kuempel, Eileen D.; Zumwalde, Ralph D.; Ristich, Anna M.; Fernback, Joseph E.; Smith, Randall J.

    2015-01-01

    Background Airborne fiber size has been shown to be an important factor relative to adverse lung effects of asbestos and suggested in animal studies of carbon nanotubes and nanofibers (CNT/CNF). Materials and Methods The International Standards Organization (ISO) transmission electron microscopy (TEM) method for asbestos was modified to increase the statistical precision of fiber size determinations, improve efficiency, and reduce analysis costs. Comparisons of the fiber size distributions and exposure indices by laboratory and counting method were performed. Results No significant differences in size distributions by the ISO and modified ISO methods were observed. Small but statistically-significant inter-lab differences in the proportion of fibers in some size bins were found, but these differences had little impact on the summary exposure indices. The modified ISO method produced slightly more precise estimates of the long fiber fraction (>15 μm). Conclusions The modified ISO method may be useful for estimating size-specific structure exposures, including CNT/CNF, for risk assessment research. PMID:25675894

  17. Therapeutic itineraries and explanations for tuberculosis: an indigenous perspective

    PubMed Central

    Nogueira, Laura Maria Vidal; Teixeira, Elizabeth; Basta, Paulo Cesar; da Motta, Maria Catarina Salvador

    2016-01-01

    ABSTRACT OBJECTIVE To analyze explanations for tuberculosis and therapeutic itineraries of Brazilian indigenous people. METHODS Case study with a qualitative-descriptive approach. We conducted semi-structured interviews with 11 Munduruku indigenous, including direct observation of treatment for tuberculosis in the municipality of Jacareacanga, south-western region of the state of Para, Brazil. To identify explanations for tuberculosis and therapeutic itineraries, we performed thematic content analysis. RESULTS Traditional medicine was the first therapeutic option chosen by the indigenous. However, biomedicine was also employed, which indicates a circulation between different therapeutic contexts and health concepts among the Munduruku. The explanations provided ranged from recognition of the signs and symptoms specific to tuberculosis to the attribution of the disease to a spirit that leaves the body and wanders in the woods, returning ill into the body. Unlike the biomedical model, which links tuberculosis transmission strictly to interpersonal contact, in closed spaces without natural lighting and ventilation (preferably domestic environments), the Munduruku associate the disease to an indirect contact between people socially distant (enemies or adversaries) in public and open places. CONCLUSIONS The explanations made by the indigenous are unique and deserve the attention of those who are responsible for developing health public policies, as well as of the teams who work on the villages. To guarantee an efficient control of tuberculosis in these regions, it is necessary that the developed actions integrate biomedicine knowledge and the traditional medicine of the indigenous people, in addition to respecting and welcoming local culture manifestations. PMID:26815161

  18. Shared Feed as a Means of Deer to Deer and Deer to Cattle Transmission of Mycobacterium bovis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human to human transmission of M. tuberculosis is primarily via a respiratory route. The focus of lesion development in the lungs in human TB patients supports inhalation as a primary means of transmission. The closely related M. bovis is the cause of tuberculosis in most animal species. In white-ta...

  19. Tuberculosis: Getting Healthy, Staying Healthy

    MedlinePlus

    Tuberculosis Getting Healthy, Staying Healthy U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Institute of Allergy and Infectious Diseases Tuberculosis Getting Healthy, Staying Healthy U.S. DEPARTMENT OF HEALTH ...

  20. Update on Veterinary Tuberculosis Vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Educational Objective: At the conclusion of this presentation, the participant will know the current status of veterinary tuberculosis vaccine research and development, and understand the challenges which remain for the future introduction of tuberculosis vaccines intended for wildlife and livestock...

  1. Identification and Genotyping of Mycobacterium tuberculosis Isolated From Water and Soil Samples of a Metropolitan City

    PubMed Central

    Velayati, Ali Akbar; Farnia, Parissa; Mozafari, Mohadese; Malekshahian, Donya; Farahbod, Amir Masoud; Seif, Shima; Rahideh, Snaz

    2015-01-01

    BACKGROUND: The potential role of environmental Mycobacterium tuberculosis in the epidemiology of TB remains unknown. We investigated the transmission of M tuberculosis from humans to the environment and the possible transmission of M tuberculosis from the environment to humans. METHODS: A total of 1,500 samples were collected from three counties of the Tehran, Iran metropolitan area from February 2012 to January 2014. A total of 700 water samples (47%) and 800 soil samples (53%) were collected. Spoligotyping and the mycobacterial interspersed repetitive units-variable number of tandem repeats typing method were performed on DNA extracted from single colonies. Genotypes of M tuberculosis strains isolated from the environment were compared with the genotypes obtained from 55 patients with confirmed pulmonary TB diagnosed during the study period in the same three counties. RESULTS: M tuberculosis was isolated from 11 of 800 soil samples (1%) and 71 of 700 water samples (10%). T family (56 of 82, 68%) followed by Delhi/CAS (11 of 82, 13.4%) were the most frequent M tuberculosis superfamilies in both water and soil samples. Overall, 27.7% of isolates in clusters were related. No related typing patterns were detected between soil, water, and clinical isolates. The most frequent superfamily of M tuberculosis in clinical isolates was Delhi/CAS (142, 30.3%) followed by NEW-1 (127, 27%). The bacilli in contaminated soil (36%) and damp water (8.4%) remained reculturable in some samples up to 9 months. CONCLUSIONS: Although the dominant M tuberculosis superfamilies in soil and water did not correspond to the dominant M tuberculosis family in patients, the presence of circulating genotypes of M tuberculosis in soil and water highlight the risk of transmission. PMID:25340935

  2. Multidrug-Resistant Tuberculosis in Europe, 2010–2011

    PubMed Central

    Günther, Gunar; van Leth, Frank; Alexandru, Sofia; Altet, Neus; Avsar, Korkut; Bang, Didi; Barbuta, Raisa; Bothamley, Graham; Ciobanu, Ana; Crudu, Valeriu; Davilovits, Manfred; Dedicoat, Martin; Duarte, Raquel; Gualano, Gina; Kunst, Heinke; de Lange, Wiel; Leimane, Vaira; Magis-Escurra, Cecile; McLaughlin, Anne-Marie; Muylle, Inge; Polcová, Veronika; Pontali, Emanuele; Popa, Christina; Rumetshofer, Rudolf; Skrahina, Alena; Solodovnikova, Varvara; Spinu, Victor; Tiberi, Simon; Viiklepp, Piret

    2015-01-01

    Drug-resistant Mycobacterium tuberculosis is challenging elimination of tuberculosis (TB). We evaluated risk factors for TB and levels of second-line drug resistance in M. tuberculosis in patients in Europe with multidrug-resistant (MDR) TB. A total of 380 patients with MDR TB and 376 patients with non–MDR TB were enrolled at 23 centers in 16 countries in Europe during 2010–2011. A total of 52.4% of MDR TB patients had never been treated for TB, which suggests primary transmission of MDR M. tuberculosis. At initiation of treatment for MDR TB, 59.7% of M. tuberculosis strains tested were resistant to pyrazinamide, 51.1% were resistant to ≥1 second-line drug, 26.6% were resistant to second-line injectable drugs, 17.6% were resistant to fluoroquinolones, and 6.8% were extensively drug resistant. Previous treatment for TB was the strongest risk factor for MDR TB. High levels of primary transmission and advanced resistance to second-line drugs characterize MDR TB cases in Europe. PMID:25693485

  3. Seasonality of Tuberculosis in the United States, 1993–2008

    PubMed Central

    Willis, Matthew D.; Winston, Carla A.; Heilig, Charles M.; Cain, Kevin P.; Walter, Nicholas D.; Mac Kenzie, William R.

    2016-01-01

    Background Although seasonal variation in tuberculosis incidence has been described in several recent studies, the mechanism underlying this seasonality remains unknown. Seasonality of tuberculosis disease may indicate the presence of season-specific risk factors that could potentially be controlled if they were better understood. We conducted this study to determine whether tuberculosis is seasonal in the United States and to describe patterns of seasonality in specific populations. Methods We performed a time series decomposition analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention from 1993 through 2008. Seasonal amplitude of tuberculosis disease (the difference between the months with the highest and lowest mean case counts), was calculated for the population as a whole and for populations with select demographic, clinical, and epidemiologic characteristics. Results A total of 243 432 laboratory-confirmed tuberculosis cases were reported over a period of 16 years. A mean of 21.4% more cases were diagnosed in March, the peak month, compared with November, the trough month. The magnitude of seasonality did not vary with latitude. The greatest seasonal amplitude was found among children aged <5 years and in cases associated with disease clusters. Conclusions Tuberculosis is a seasonal disease in the United States, with a peak in spring and trough in late fall. The latitude independence of seasonality suggests that reduced winter sunlight exposure may not be a strong contributor to tuberculosis risk. Increased seasonality among young children and clustered cases suggests that disease that is the result of recent transmission is more influenced by season than disease resulting from activation of latent infection. PMID:22474225

  4. Comparing HIV prevalence estimates from prevention of mother-to-child HIV transmission programme and the antenatal HIV surveillance in Addis Ababa

    PubMed Central

    2012-01-01

    Background In the absence of reliable data, antenatal HIV surveillance has been used to monitor the HIV epidemic since the late 1980s. Currently, routine data from Prevention of Mother-to-child HIV transmission (PMTCT) programmes are increasingly available. Evaluating whether the PMTCT programme reports provide comparable HIV prevalence estimates with the antenatal surveillance reports is important. In this study, we compared HIV prevalence estimates from routine PMTCT programme and antenatal surveillance in Addis Ababa with the aim to come up with evidence based recommendation. Methods Summary data were collected from PMTCT programmes and antenatal surveillance reports within the catchment of Addis Ababa. The PMTCT programme data were obtained from routine monthly reports from 2004 to 2009 and from published antenatal HIV surveillance reports from 2003 to 2009. Data were analysed using descriptive statistics. Results In Addis Ababa, PMTCT sites had increased from six in 2004 to 54 in 2009. The site expansion was accompanied by an increased number of women testing. There were marked increases in the rate of HIV testing following the introduction of routine opt-out HIV testing approach. Paralleling these increases, the HIV prevalence showed a steady decline from 10.0% in 2004 to 4.5% in 2009. There were five antenatal surveillance sites from 2003 to 2007 in Addis Ababa and they increased to seven by 2009. Four rounds of surveillance data from five sites showed a declining trend in HIV prevalence over the years. The overall antenatal surveillance data also showed that the HIV prevalence among antenatal attendees had declined from 12.4% in 2003 to 5.5% in 2009. The HIV prevalence estimates from PMTCT programme were 6.2% and 4.5% and from antenatal surveillance 6.1 and 5.5% in 2008 and 2009 respectively. Conclusions There were consistent HIV prevalence estimates from PMTCT programme and from antenatal surveillance reports. Both data sources showed a marked decline in

  5. [Tuberculosis in compromised hosts].

    PubMed

    2003-11-01

    Recent development of tuberculosis in Japan tends to converge on a specific high risk group. The proportion of tuberculosis developing particularly from the compromised hosts in the high risk group is especially high. At this symposium, therefore, we took up diabetes mellitus, gastrectomy, dialysis, AIDS and the elderly for discussion. Many new findings and useful reports for practical medical treatment are submitted; why these compromised hosts are predisposed to tuberculosis, tuberculosis diagnostic and remedial notes of those compromised hosts etc. It is an important question for the future to study how to prevent tuberculosis from these compromised hosts. 1. Tuberculosis in diabetes mellitus: aggravation and its immunological mechanism: Kazuyoshi KAWAKAMI (Department of Internal Medicine, Division of Infectious Diseases, Graduate School and Faculty of Medicine, University of the Ryukyus). It has been well documented that diabetes mellitus (DM) is a major aggravating factor in tuberculosis. The onset of this disease is more frequent in DM patients than in individuals with any underlying diseases. However, the precise mechanism of this finding remains to be fully understood. Earlier studies reported that the migration, phagocytosis and bactericidal activity of neutrophils are all impaired in DM patients, which is related to their reduced host defense to infection with extracellular bacteria, such as S. aureus and E. colli. Host defense to mycobacterial infection is largely mediated by cellular immunity, and Th1-related cytokines, such as IFN-gamma and IL-12, play a central role in this response. It is reported that serum level of these cytokines and their production by peripheral blood mononuclear cells (PBMC) are reduced in tuberculosis patients with DM, and this is supposed to be involved in the high incidence of tuberculosis in DM. Our study observed similar findings and furthermore indicated that IFN-gamma and IL-12 production by BCG-stimulated PBMC was lower

  6. Tuberculosis among Children in Alaska.

    ERIC Educational Resources Information Center

    Gessner, Bradford D.

    1997-01-01

    The incidence of tuberculosis among Alaskan children under 15 was more than twice the national rate, with Alaska Native children showing a much higher incidence. Children with household exposure to adults with active tuberculosis had a high risk of infection. About 22 percent of pediatric tuberculosis cases were identified through school…

  7. Tuberculosis: A Problem for Lifeguards?

    ERIC Educational Resources Information Center

    Skaros, Susan

    1996-01-01

    Lifeguards run the risk of workplace infection by tuberculosis-carrying swimmers. Even if they work in ventilated, sunlit areas (which reduces risk), they can contract tuberculosis when performing respiratory resuscitation. Without appropriate precautions, lifeguards may be unnecessarily exposed. A tuberculosis infection control plan is needed in…

  8. Tuberculosis-resistant transgenic cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tuberculosis is a devastating disease that affects humans and many animal species. In humans, tuberculosis (TB) is mainly caused by Mycobacterium tuberculosis, while most cases in cattle are caused by Mycobacterium bovis. However, Mb can also cause, albeit rarely, human TB. In this issue, Wu et al. ...

  9. Childhood Tuberculosis, Still with Us...

    ERIC Educational Resources Information Center

    Chaulet, Pierre; And Others

    1992-01-01

    The first section of this report on childhood tuberculosis in developed and developing countries discusses the epidemiology of tuberculosis in children. Information is presented on: (1) sources and prevalence of infection; (2) risks, frequency, and types of tuberculosis; (3) mortality rates; and (4) the relation of poverty and AIDS to…

  10. [Lymph node tuberculosis in adults].

    PubMed

    Pimentel, M; Follador, E C; Barbas, C S; Stávale, M L; Oliveira-Vianna, E dos S; Barbas Filho, J V; Leite, O M; de Carvalho, C R

    1991-01-01

    Tuberculous lymphadenitis is a form of extrapulmonary tuberculosis that was observed in 8.4% of all cases with tuberculosis in our series. In all instances the organism isolated was M. tuberculosis. There was a high rate of PPD positiveness. The chemotherapy yielded good results. The evolution was satisfactory in 75% of the patients treated for six months. PMID:1843715

  11. Model-based estimates of risks of disease transmission and economic costs of seven injection devices in sub-Saharan Africa.

    PubMed Central

    Ekwueme, Donatus U.; Weniger, Bruce G.; Chen, Robert T.

    2002-01-01

    OBJECTIVE: To investigate and compare seven types of injection devices for their risks of iatrogenic transmission of bloodborne pathogens and their economic costs in sub-Saharan Africa. METHODS: Risk assumptions for each device and cost models were constructed to estimate the number of new hepatitis B virus (HBV) and human immunodeficiency virus (HIV) infections resulting from patient-to-patient, patient-to-health care worker, and patient-to-community transmission. Costs of device purchase and usage were derived from the literature, while costs of direct medical care and lost productivity from HBV and HIV disease were based on data collected in 1999 in Côte d'Ivoire, Ghana, and Uganda. Multivariate sensitivity analyses using Monte Carlo simulation characterized uncertainties in model parameters. Costs were summed from both the societal and health care system payer's perspectives. FINDINGS: Resterilizable and disposable needles and syringes had the highest overall costs for device purchase, usage, and iatrogenic disease: median US dollars 26.77 and US dollars 25.29, respectively, per injection from the societal perspective. Disposable-cartridge jet injectors and automatic needle-shielding syringes had the lowest costs, US dollars 0.36 and US dollars 0.80, respectively. Reusable-nozzle jet injectors and auto-disable needle and syringes were intermediate, at US dollars 0.80 and US dollars 0.91, respectively, per injection. CONCLUSION: Despite their nominal purchase and usage costs, conventional needles and syringes carry a hidden but huge burden of iatrogenic disease. Alternative injection devices for the millions of injections administered annually in sub-Saharan Africa would be of value and should be considered by policy-makers in procurement decisions. PMID:12481207

  12. Tuberculosis and the Risk of Infection with Other Intracellular Bacteria: a Population-Based Study

    PubMed Central

    Huaman, M. A.; Fiske, C. T.; Jones, T. F.; Warkentin, J.; Shepherd, B. E.; Ingram, L.A.; Maruri, F.; Sterling, T. R.

    2014-01-01

    SUMMARY Persons who develop tuberculosis may have subtle immune defects that could predispose to other intracellular bacterial infections (ICBIs). We obtained data on tuberculosis and five ICBIs (Chlamydia trachomatis,Salmonella spp., Shigella spp., Yersinia spp., and Listeria monocytogenes) reported to the Tennessee Department of Health, USA, 2000–2011. Incidence rate ratios (IRRs) comparing ICBIs in persons who developed tuberculosis and ICBIs in the Tennessee population, adjusted for age, sex, race and ethnicity were estimated. IRRs were not significantly elevated for all ICBIs combined (IRR, 0.87, 95%CI: 0.71–1.06). C. trachomatis rate was lowest in the year post-tuberculosis diagnosis (IRR, 0.17; 95%CI, 0.04–0.70). More Salmonella infections occurred in extrapulmonary tuberculosis compared to pulmonary tuberculosis patients (IRR, 14.3, 95%CI: 1.67–122); however, this appeared to be related to HIV-coinfection. Tuberculosis was not associated with an increased risk of other ICBIs. In fact, fewer C. trachomatis infections occurred after recent tuberculosis diagnosis. Reasons for this association, including reduced exposure, protection conferred by anti-tuberculosis drugs or macrophage activation by M. tuberculosis infection warrant further investigation. PMID:25148655

  13. Forecast Model Analysis for the Morbidity of Tuberculosis in Xinjiang, China

    PubMed Central

    Zheng, Yan-Ling; Zhang, Li-Ping; Zhang, Xue-Liang; Wang, Kai; Zheng, Yu-Jian

    2015-01-01

    Tuberculosis is a major global public health problem, which also affects economic and social development. China has the second largest burden of tuberculosis in the world. The tuberculosis morbidity in Xinjiang is much higher than the national situation; therefore, there is an urgent need for monitoring and predicting tuberculosis morbidity so as to make the control of tuberculosis more effective. Recently, the Box-Jenkins approach, specifically the autoregressive integrated moving average (ARIMA) model, is typically applied to predict the morbidity of infectious diseases; it can take into account changing trends, periodic changes, and random disturbances in time series. Autoregressive conditional heteroscedasticity (ARCH) models are the prevalent tools used to deal with time series heteroscedasticity. In this study, based on the data of the tuberculosis morbidity from January 2004 to June 2014 in Xinjiang, we establish the single ARIMA (1, 1, 2) (1, 1, 1)12 model and the combined ARIMA (1, 1, 2) (1, 1, 1)12-ARCH (1) model, which can be used to predict the tuberculosis morbidity successfully in Xinjiang. Comparative analyses show that the combined model is more effective. To the best of our knowledge, this is the first study to establish the ARIMA model and ARIMA-ARCH model for prediction and monitoring the monthly morbidity of tuberculosis in Xinjiang. Based on the results of this study, the ARIMA (1, 1, 2) (1, 1, 1)12-ARCH (1) model is suggested to give tuberculosis surveillance by providing estimates on tuberculosis morbidity trends in Xinjiang, China. PMID:25760345

  14. Counting Children with Tuberculosis: Why Numbers Matter

    PubMed Central

    Seddon, James A; Jenkins, Helen E; Liu, Li; Cohen, Ted; Black, Robert E; Becerra, Mercedes C.; Graham, Stephen M; Sismanidis, Charalambos; Dodd, Peter J

    2016-01-01

    Summary In the last five years, childhood tuberculosis (TB) has received increasing attention from international organisations, national tuberculosis programmes, and academics. For the first time, a number of different groups are developing techniques to estimate the burden of childhood TB. We review the challenges in diagnosing TB in children and the reasons cases in children can go unreported. We discuss the importance of an accurate understanding of burden for identifying problems in programme delivery, targeting interventions, monitoring trends, setting targets, allocating resources appropriately and providing strong advocacy. We briefly review the estimates produced by new analytical methods, outline the reasons for recent improvements in our understanding, and potential future directions. We conclude that while innovation, collaboration and better data have improved our understanding of childhood TB burden, it remains substantially incomplete. PMID:26564535

  15. Scale up: meeting targets in global tuberculosis control.

    PubMed

    Elzinga, Gijs; Raviglione, Mario C; Maher, Dermot

    2004-03-01

    Despite great progress, global targets for tuberculosis case detection and cure might not be reached by 2005. In particular, there is a serious case-detection gap between estimated annual incident cases and those reported under the strategy for tuberculosis control branded as DOTS. Delays in reaching targets result in lack of effect on incidence of disease, which is of particular concern in regions where incidence is increasing-eg, sub-Saharan Africa and the former Soviet Union. Four key actions will speed up progress towards reaching global targets: 1) equipping national tuberculosis programmes to have a stewardship role in engaging all health providers in implementing the DOTS strategy; 2) establishing the feasibility of national certification systems of DOTS coverage; 3) promoting community action to contribute to patient care and to voice demand for the DOTS strategy; and 4) increasing support to sub-Saharan Africa for implementation of a strategy of expanded scope to counter HIV-1-fuelled tuberculosis. PMID:15016493

  16. Transregional movement of multidrug-resistant tuberculosis in north China: an underlying threat to tuberculosis control

    PubMed Central

    An, Jun; Gao, Mengqiu; Chu, Naihui; Huang, Hairong; Pang, Yu; Li, Liang

    2016-01-01

    Due to unbalanced distribution of health care resource in China, tuberculosis patients, especially multidrug-resistant tuberculosis (MDR-TB), prefer to suffer transregional movement for seeking better health care service in the first-tier cities. Here, we performed a study on the current status of transregional movement of tuberculosis in northern China by reviewing the medical record of TB patients hospitalized in Beijing Chest Hospital from 2011 to 2015. From 2011 to 2015, the proportion of non-Beijing in-patients had increased from 55.0% (996/1810) to 67.2% (1860/2769). In addition, we found that the rate of re-treated among non-Beijing group was significantly higher than that among Beijing-group. Compared with the proportion of pulmonary TB patients from non-Beijing, there were more extra-pulmonary TB patients from non-Beijing. In addition, 10.5% (164/1568) of Beijing in-patients and 26.5% (491/1858) of non-Beijing in-patients had MDR tuberculosis, and statistical analysis revealed that there was significantly higher proportion of MDR cases among non-Beijing group than Beijing group. In conclusion, our data demonstrate that an increasing proportion of TB patients from northern China seek health care in Beijing. In view of higher prevalence of MDR-TB cases among these patients, the transregional movement of MDR-TB will lead to ongoing MDR TB transmission in the community. PMID:27411739

  17. Transregional movement of multidrug-resistant tuberculosis in north China: an underlying threat to tuberculosis control.

    PubMed

    An, Jun; Gao, Mengqiu; Chu, Naihui; Huang, Hairong; Pang, Yu; Li, Liang

    2016-01-01

    Due to unbalanced distribution of health care resource in China, tuberculosis patients, especially multidrug-resistant tuberculosis (MDR-TB), prefer to suffer transregional movement for seeking better health care service in the first-tier cities. Here, we performed a study on the current status of transregional movement of tuberculosis in northern China by reviewing the medical record of TB patients hospitalized in Beijing Chest Hospital from 2011 to 2015. From 2011 to 2015, the proportion of non-Beijing in-patients had increased from 55.0% (996/1810) to 67.2% (1860/2769). In addition, we found that the rate of re-treated among non-Beijing group was significantly higher than that among Beijing-group. Compared with the proportion of pulmonary TB patients from non-Beijing, there were more extra-pulmonary TB patients from non-Beijing. In addition, 10.5% (164/1568) of Beijing in-patients and 26.5% (491/1858) of non-Beijing in-patients had MDR tuberculosis, and statistical analysis revealed that there was significantly higher proportion of MDR cases among non-Beijing group than Beijing group. In conclusion, our data demonstrate that an increasing proportion of TB patients from northern China seek health care in Beijing. In view of higher prevalence of MDR-TB cases among these patients, the transregional movement of MDR-TB will lead to ongoing MDR TB transmission in the community. PMID:27411739

  18. Tuberculosis Risk among Medical Trainees, Pune, India

    PubMed Central

    Chandanwale, Ajay; Patil, Akhil; Kadam, Dileep; Joshi, Samir; Gupte, Nikhil; McIntire, Katie; Jain, Divyashri; Dalal, Hamza; Badave, Rohan; DeLuca, Andrea; Gupta, Amita; Bollinger, Robert; Mave, Vidya

    2016-01-01

    During 2012–2013, at a public hospital in Pune, India, 26 (3.9%) cases of tuberculosis were reported among 662 medical trainees, representing an estimated incidence of 3,279 cases/100,000 person-years. Three of these infections were isoniazid-resistant, 1 was multidrug-resistant, and 1 occurred in a trainee who had fulminant hepatitis after starting treatment for TB. PMID:26889712

  19. The Importance of First Impressions: Early Events in Mycobacterium tuberculosis Infection Influence Outcome

    PubMed Central

    Cadena, Anthony M.; Fortune, Sarah M.

    2016-01-01

    ABSTRACT Tuberculosis remains a major health threat in much of the world. New vaccines against Mycobacterium tuberculosis are essential for preventing infection, disease, and transmission. However, the host immune responses that need to be induced by an effective vaccine remain unclear. Increasingly, it has become clear that early events in infection are of major importance in the eventual outcome of the infection. Studying such events in humans is challenging, as they occur within the lung and thoracic lymph nodes, and any clinical signs of early infection are relatively nonspecific. Nonetheless, clinical studies and animal models of tuberculosis have provided new insights into the local events that occur in the first few weeks of tuberculosis. Development of an effective vaccine requires a clear understanding of the successful (and detrimental) early host responses against M. tuberculosis, with the goal to improve upon natural immune responses and prevent infection or disease. PMID:27048801

  20. Tuberculosis and HIV Coinfection.

    PubMed

    Bruchfeld, Judith; Correia-Neves, Margarida; Källenius, Gunilla

    2015-07-01

    Tuberculosis (TB) and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) constitute the main burden of infectious disease in resource-limited countries. In the individual host, the two pathogens, Mycobacterium tuberculosis and HIV, potentiate one another, accelerating the deterioration of immunological functions. In high-burden settings, HIV coinfection is the most important risk factor for developing active TB, which increases the susceptibility to primary infection or reinfection and also the risk of TB reactivation for patients with latent TB. M. tuberculosis infection also has a negative impact on the immune response to HIV, accelerating the progression from HIV infection to AIDS. The clinical management of HIV-associated TB includes the integration of effective anti-TB treatment, use of concurrent antiretroviral therapy (ART), prevention of HIV-related comorbidities, management of drug cytotoxicity, and prevention/treatment of immune reconstitution inflammatory syndrome (IRIS). PMID:25722472

  1. Estimated health and economic impact of quadrivalent HPV (types 6/11/16/18) vaccination in Brazil using a transmission dynamic model

    PubMed Central

    2012-01-01

    Background Cervical cancer is the second most common cancer among women in Brazil. We examined the health and economic impacts of quadrivalent HPV vaccination in Brazil. Methods We adapted a previously developed transmission dynamic model to estimate the effectiveness of HPV vaccination on cervical cancer, cervical intraepithelial neoplasia grades 2 and 3 (CIN2/3), CIN1, and genital warts. We evaluated following vaccination strategies: routine vaccination of 12-year-old girls and routine vaccination in combination with a catch-up vaccination of 12 to 26-year-old women. Results The model projected that the vaccination would reduce the incidence rates of HPV 6/11/16/18-related cervical cancer, CIN2/3, CIN1, and female genital warts by 94% to 98% at year 100. Routine vaccination in combination with a catch-up vaccination could prevent approximately 163,000 cases of cervical cancer, 48,000 deaths from cervical cancer, 2.3 million cases of CIN2/3, and 11.4 million genital warts in the next 50 years. The incremental cost-effectiveness ratios for female vaccination strategies ranged from R$350 to R$720 (US$219 to US$450) per quality-adjusted life year (QALY) gained. Conclusions Our study demonstrates that quadrivalent HPV female vaccination can be a cost-effective public health intervention that can substantially reduce the burden of cervical diseases and genital warts in Brazil. PMID:23046886

  2. Near-bottom suspended matter concentration on the Continental Shelf during storms: estimates based on in situ observations of light transmission and a particle size dependent transmissometer calibration

    USGS Publications Warehouse

    Moody, J.A.; Butman, B.; Bothner, Michael H.

    1987-01-01

    A laboratory calibration of Sea Tech and Montedoro-Whitney beam transmissometers shows a linear relation between light attenuation coefficient (cp) and suspended matter concentration (SMC) for natural sediments and for glass beads. However the proportionality constant between cp and SMC depends on the particle diameter and particle type. Thus, to measure SMC, observations of light attenuation must be used with a time-variable calibration when suspended particle characteristics change with time. Because of this variable calibration, time series of light attenuation alone may not directly reflect SMC and must be interpreted with care. The near-bottom concentration of suspended matter during winter storms on the U.S. East Coast Continental Shelf is estimated from light transmission measurements made 2 m above the bottom and from the size distribution of suspended material collected simultaneously in sediment traps 3 m above the bottom. The average concentrations during six storms between December 1979 and February 1980 in the Middle Atlantic Bight ranged from 2 to 4 mg l1 (maximum concentration of 7 mg l1) and 8 to 12 mg l1 (maximum concentration of 22 mg l1) on the south flank of Georges Bank. ?? 1987.

  3. [A clinical study on tuberculosis among young adults in Japan: analysis on patients admitted to national hospitals in Kanto- and Kinki-areas in the year 2000].

    PubMed

    Yotsumoto, Hideki; Yonemaru, Makoto; Suzuki, Katsuhiro; Kawabe, Yoshiko; Sasaki, Yuka; Toyoda, Emiko; Yamagishi, Fumio; Kudoh, Koichiro; Kurasawa, Takuya; Ito, Masami; Kawashiro, Takeo; Sakatani, Mitsunori; Mori, Masashi

    2003-08-01

    Considering the high social activity, the trend of tuberculosis among young adults appears to be one of the key factors that influence the future morbidity rate of tuberculosis in Japan. To investigate its current characteristics, we analyzed new cases of tuberculosis aged 20 to 29 who were admitted to 7 national hospitals in Kanto- and Kinki-areas during the period of January 1st to December 31st, 2000. Data on the following items were compiled: sex, age, body height and weight, nationality; background factors such as life style, complications; course of the disease before the diagnosis; result of PPD skin test; severity of the disease estimated by the amount of M. tuberculosis in sputum and the grade of chest X-ray findings; therapeutic regimens and the response rate. Data were collected from 234 patients (129 males and 105 females) and the results were as follows: 1) about 80% of the patients were symptomatic and in 50% of patients who presented with cough, more than one month was needed before establishing the diagnosis as TB, 2) the disease was found in advanced stage in more than half of the patients, 3) foreigner patients, most of them were from Kanto-area, accounted for 11%, and were in advanced stage, some with drug-resistant tuberculosis, 4) INH resistance was noted in 7.7%, 5) pyrazinamide was included in the therapeutic regimens in 84.0% of the smear positive patients, 6) the admission period was within 90 days in 63.7% of the patients, however, the duration of treatment was 6 months in only 48.0% of patients who were treated with regimens containing pyrazinamide. More efforts for early detection of patients is needed to prevent the transmission of the disease, and more extensive use of directly observed therapy is essential for the prevention of dropout. We also argued about the shortening of the admission and duration of treatment in these patients. PMID:14509224

  4. Tuberculosis and HIV co-infection in children

    PubMed Central

    2014-01-01

    HIV is the top and tuberculosis is the second leading cause of death from infectious disease worldwide, with an estimated 8.7 million incident cases of tuberculosis and 2.5 million new HIV infections annually. The World Health Organization estimates that HIV prevalence among children with tuberculosis, in countries with moderate to high prevalence, ranges from 10 to 60%. The mechanisms promoting susceptibility of people with HIV to tuberculosis disease are incompletely understood, being likely caused by multifactorial processes. Paediatric tuberculosis and HIV have overlapping clinical manifestations, which could lead to missed or late diagnosis. Although every effort should be made to obtain a microbiologically-confirmed diagnosis in children with tuberculosis, in reality this may only be achieved in a minority, reflecting their paucibacillary nature and the difficulties in obtain samples. Rapid polymerase chain reaction tests, such as Xpert MTB/RIF assay, are increasingly used in children. The use of less or non invasive methods of sample collection, such as naso-pharyngeal aspirates and stool samples for a polymerase chain reaction-based diagnostic test tests and mycobacterial cultures is promising technique in HIV negative and HIV positive children. Anti-tuberculosis treatment should be started immediately at diagnosis with a four drug regimen, irrespective of the disease severity. Moreover, tuberculosis disease in an HIV infected child is considered to be a clinical indication for initiation of antiretroviral treatment. The World Health Organization recommends starting antiretroviral treatment in children as soon as anti-tuberculosis treatment is tolerated and within 2- 8 weeks after initiating it. The treatment of choice depends on the child’s age and availability of age-appropriate formulations, and potential drug interactions and resistance. Treatment of multi-drug resistant tuberculosis in HIV-infected children follows same principles as for HIV

  5. [Tuberculosis pulmonum--"threaten us of epidemic"?].

    PubMed

    Chyczewska, Elzbieta

    2008-01-01

    Tuberculosis (TB) remains a deadly infectious disease affecting millions of people worldwide with 95% of cases and 98% of deaths occuring in developing countries (9 milion new cases, 1 million deaths annually) vs.WHO. Tuberculosis is on the increase in developed countries, because of AIDS, the use of immunosuppresive drugs which depress the host defence mechanism, decreased socioeconomic conditions, as well as increased immigration of persons from areas of high endemicity. The major reason for this increase was because of rapid rise in cases from sub-Saharan Africa (due to AIDS) nad Russia. Incidense of tuberculosis in Poland 2007--the number of notified cases was 8014. Pulmonary cases represented 92.7% of total all TB cases and 628 cases of extrapulmonary TB. Chidren TB cases represented 0.9% (74 cases) of all cases notified in Poland. The incidence of tuberculosis increases with age from 1.1 in children do 41.2 among 65 and older. The incidence of men (31.5) was two times higher than in women--14.5 per 100 000 respectivly. There were 716 deaths due to pulmonary TB and 23 from extrapulmonary TB. Multidrug resistance (MDR) of Mycobacterium tuberculosis is a major therapeutic problem, in the world, with a high mortality and occurs mainly in HIV-infected patients. The WHO estimates that around 50 million people are infected with MDR-TB! WHO suggest that a greater investment in the establishment treatment strategy of DOTS (Directly Observed Treatment Short-course) into all posible regions. PMID:22320031

  6. Tuberculosis in Older Adults.

    PubMed

    Rajagopalan, Shobita

    2016-08-01

    Tuberculosis (TB) remains one of the world's most lethal infectious diseases. Preventive and control strategies among other high-risk groups, such as the elderly population, continues to be a challenge. Clinical features of TB in older adults may be atypical and confused with age-related diseases. Diagnosis and management of TB in the elderly person can be difficult; treatment can be associated with adverse drug reactions. This article reviews the current global epidemiology, pathogenesis, clinical characteristics, diagnosis, management, and prevention of Mycobacterium tuberculosis infection in community-dwelling and institutionalized aging adults. PMID:27394018

  7. [The immunology of tuberculosis].

    PubMed

    Tokunaga, T

    1989-02-01

    An introductory overview on the present state and future prospect of the immunology of tuberculosis is presented with the following six chapters. 1. Contribution of tuberculosis immunologists to the modern immunology. When one reminds Koch's phenomenon, Freund's adjuvant, and the findings or new ideas of, for instance, cell-mediated transfer of tuberculin allergy, test of MIF which was first described as "lymphokines", effector macrophages activated with immune lymphocytes against mycobacterial infection, MHC-restriction for presenting tuberculin-antigen from macrophages to T cells, everyone may agree with saying that the tuberculosis immunology contributed greatly to the opening and development of modern immunology. 2. Central dogma of tuberculosis immunology. Tuberculosis immunology possesses a central dogma : infection of tubercle bacilli----phagocytosis----antigen presentation----expansion of specific T cell clone----production of lymphokines----macrophage activation----killing of the bacilli. Recent knowledges from modern immunology have clarified many things in or around this immunological process. However, there remain many important questions. In the following chapters and subtitles, what have been clarified and what are still unsolved will be described. 3. Induction of tuberculosis immunity. (1) Mechanisms of phagocytosis with macrophages, and natural resistance. (2) Antigen presentation and sensitized T cells. 4. Expression of tuberculosis immunity. (1) Lymphokines. (2) Activation of macrophages. (3) Immune suppression. 5. Special characters of tubercle bacilli in relation to the host response. Biochemistry of cellular components of tubercle bacilli and their biological activities have been reported by many investigators already in this journal. Therefore, the following items only are discussed here. (1) Mycobacterial proteins produced by gene-technology. (2) Adjuvant active derivatives of MDP. (3) DNA from BCG and its biological activities. (4

  8. Predicting tuberculosis among migrant groups.

    PubMed

    Watkins, R E; Plant, A J

    2002-12-01

    In industrialized countries migrants remain a high-risk group for tuberculosis (TB). Multiple linear regression analysis was used to determine the ability of indicators of TB incidence in the country of birth to predict the incidence of TB among migrants in Australia during 1997. World Health Organization total case notifications, new smear-positive case notifications and the estimated incidence of TB by country of birth explained 55, 69 and 87% of the variance in TB incidence in Australia, respectively. Gross national income of the country of birth and unemployment level in Australia were also significant predictors of TB in migrant groups. Indicators of the incidence of TB in the country of birth are the most important group-level predictors of the rate of TB among migrants in Australia. PMID:12558347

  9. Addressing institutional amplifiers in the dynamics and control of tuberculosis epidemics.

    PubMed

    Basu, Sanjay; Stuckler, David; McKee, Martin

    2011-01-01

    Tuberculosis outbreaks originating in prisons, mines, or hospital wards can spread to the larger community. Recent proposals have targeted these high-transmission institutional amplifiers by improving case detection, treatment, or reducing the size of the exposed population. However, what effects these alternative proposals may have is unclear. We mathematically modeled these control strategies and found case detection and treatment methods insufficient in addressing epidemics involving common types of institutional amplifiers. Movement of persons in and out of amplifiers fundamentally altered the transmission dynamics of tuberculosis in a manner not effectively mitigated by detection or treatment alone. Policies increasing the population size exposed to amplifiers or the per-person duration of exposure within amplifiers potentially worsened incidence, even in settings with high rates of detection and treatment success. However, reducing the total population size entering institutional amplifiers significantly lowered tuberculosis incidence and the risk of propagating new drug-resistant tuberculosis strains. PMID:21212197

  10. Human Exposure following Mycobacterium tuberculosis Infection of Multiple Animal Species in a Metropolitan Zoo

    PubMed Central

    Oh, Peter; Granich, Reuben; Scott, Jim; Sun, Ben; Joseph, Michael; Stringfield, Cynthia; Thisdell, Susan; Staley, Jothan; Workman-Malcolm, Donna; Borenstein, Lee; Lehnkering, Eleanor; Ryan, Patrick; Soukup, Jeanne; Nitta, Annette

    2002-01-01

    From 1997 to 2000, Mycobacterium tuberculosis was diagnosed in two Asian elephants (Elephas maximus), three Rocky Mountain goats (Oreamnos americanus), and one black rhinoceros (Diceros bicornis) in the Los Angeles Zoo. DNA fingerprint patterns suggested recent transmission. An investigation found no active cases of tuberculosis in humans; however, tuberculin skin-test conversions in humans were associated with training elephants and attending an elephant necropsy. PMID:12453358

  11. Cough Aerosols of Mycobacterium tuberculosis Predict New Infection. A Household Contact Study

    PubMed Central

    Namugga, Olive; Mumbowa, Francis; Ssebidandi, Martin; Mbabazi, Olive; Moine, Stephanie; Mboowa, Gerald; Fox, Matthew P.; Reilly, Nancy; Ayakaka, Irene; Kim, Soyeon; Okwera, Alphonse; Joloba, Moses; Fennelly, Kevin P.

    2013-01-01

    Rationale: Airborne transmission of Mycobacterium tuberculosis results from incompletely characterized host, bacterial, and environmental factors. Sputum smear microscopy is associated with considerable variability in transmission. Objectives: To evaluate the use of cough-generated aerosols of M. tuberculosis to predict recent transmission. Methods: Patients with pulmonary tuberculosis (TB) underwent a standard evaluation and collection of cough aerosol cultures of M. tuberculosis. We assessed household contacts for new M. tuberculosis infection. We used multivariable logistic regression analysis with cluster adjustment to analyze predictors of new infection. Measurements and Main Results: From May 2009 to January 2011, we enrolled 96 sputum culture-positive index TB cases and their 442 contacts. Only 43 (45%) patients with TB yielded M. tuberculosis in aerosols. Contacts of patients with TB who produced high aerosols (≥10 CFU) were more likely to have a new infection compared with contacts from low-aerosol (1–9 CFU) and aerosol-negative cases (69%, 25%, and 30%, respectively; P = 0.009). A high-aerosol patient with TB was the only predictor of new M. tuberculosis infection in unadjusted (odds ratio, 5.18; 95% confidence interval, 1.52–17.61) and adjusted analyses (odds ratio, 4.81; 95% confidence interval, 1.20–19.23). Contacts of patients with TB with no aerosols versus low and high aerosols had differential tuberculin skin test and interferon-γ release assay responses. Conclusions: Cough aerosols of M. tuberculosis are produced by a minority of patients with TB but predict transmission better than sputum smear microscopy or culture. Cough aerosols may help identify the most infectious patients with TB and thus improve the cost-effectiveness of TB control programs. PMID:23306539

  12. Population genomics of Mycobacterium tuberculosis in the Inuit.

    PubMed

    Lee, Robyn S; Radomski, Nicolas; Proulx, Jean-Francois; Levade, Ines; Shapiro, B Jesse; McIntosh, Fiona; Soualhine, Hafid; Menzies, Dick; Behr, Marcel A

    2015-11-01

    Nunavik, Québec suffers from epidemic tuberculosis (TB), with an incidence 50-fold higher than the Canadian average. Molecular studies in this region have documented limited bacterial genetic diversity among Mycobacterium tuberculosis isolates, consistent with a founder strain and/or ongoing spread. We have used whole-genome sequencing on 163 M. tuberculosis isolates from 11 geographically isolated villages to provide a high-resolution portrait of bacterial genetic diversity in this setting. All isolates were lineage 4 (Euro-American), with two sublineages present (major, n = 153; minor, n = 10). Among major sublineage isolates, there was a median of 46 pairwise single-nucleotide polymorphisms (SNPs), and the most recent common ancestor (MRCA) was in the early 20th century. Pairs of isolates within a village had significantly fewer SNPs than pairs from different villages (median: 6 vs. 47, P < 0.00005), indicating that most transmission occurs within villages. There was an excess of nonsynonymous SNPs after the diversification of M. tuberculosis within Nunavik: The ratio of nonsynonymous to synonymous substitution rates (dN/dS) was 0.534 before the MRCA but 0.777 subsequently (P = 0.010). Nonsynonymous SNPs were detected across all gene categories, arguing against positive selection and toward genetic drift with relaxation of purifying selection. Supporting the latter possibility, 28 genes were partially or completely deleted since the MRCA, including genes previously reported to be essential for M. tuberculosis growth. Our findings indicate that the epidemiologic success of M. tuberculosis in this region is more likely due to an environment conducive to TB transmission than a particularly well-adapted strain. PMID:26483462

  13. Population genomics of Mycobacterium tuberculosis in the Inuit

    PubMed Central

    Lee, Robyn S.; Radomski, Nicolas; Proulx, Jean-Francois; Levade, Ines; Shapiro, B. Jesse; McIntosh, Fiona; Soualhine, Hafid; Menzies, Dick; Behr, Marcel A.

    2015-01-01

    Nunavik, Québec suffers from epidemic tuberculosis (TB), with an incidence 50-fold higher than the Canadian average. Molecular studies in this region have documented limited bacterial genetic diversity among Mycobacterium tuberculosis isolates, consistent with a founder strain and/or ongoing spread. We have used whole-genome sequencing on 163 M. tuberculosis isolates from 11 geographically isolated villages to provide a high-resolution portrait of bacterial genetic diversity in this setting. All isolates were lineage 4 (Euro-American), with two sublineages present (major, n = 153; minor, n = 10). Among major sublineage isolates, there was a median of 46 pairwise single-nucleotide polymorphisms (SNPs), and the most recent common ancestor (MRCA) was in the early 20th century. Pairs of isolates within a village had significantly fewer SNPs than pairs from different villages (median: 6 vs. 47, P < 0.00005), indicating that most transmission occurs within villages. There was an excess of nonsynonymous SNPs after the diversification of M. tuberculosis within Nunavik: The ratio of nonsynonymous to synonymous substitution rates (dN/dS) was 0.534 before the MRCA but 0.777 subsequently (P = 0.010). Nonsynonymous SNPs were detected across all gene categories, arguing against positive selection and toward genetic drift with relaxation of purifying selection. Supporting the latter possibility, 28 genes were partially or completely deleted since the MRCA, including genes previously reported to be essential for M. tuberculosis growth. Our findings indicate that the epidemiologic success of M. tuberculosis in this region is more likely due to an environment conducive to TB transmission than a particularly well-adapted strain. PMID:26483462

  14. Tuberculosis Facts - TB and HIV/AIDS

    MedlinePlus

    Tuberculosis (TB) Facts TB and HIV/AIDS What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  15. Antigen smuggling in tuberculosis.

    PubMed

    Hudrisier, Denis; Neyrolles, Olivier

    2014-06-11

    The importance of CD4 T lymphocytes in immunity to M. tuberculosis is well established; however, how dendritic cells activate T cells in vivo remains obscure. In this issue of Cell Host & Microbe, Srivastava and Ernst (2014) report a mechanism of antigen transfer for efficient activation of antimycobacterial T cells. PMID:24922567

  16. [Tuberculosis of ankle].

    PubMed

    Rubio Barbón, S; Rodríguez Cocina, B; Suárez del Villar Acebal, R; Calvo Rodríguez, C E; Villar López, A; Escalada Rodríguez, P; Torreblanca Gil, A

    2004-09-01

    The authors present a case of tuberculous arthritis of ankle with sinovial fluid and sputum aspirate Lowenstein positive (M. tuberculosis) in a patient non inmunocomprometid and review the clinical, diagnosis and treatment aspects of this entity, and show the difficult diagnosis in cases of radiology normal or low suspect. PMID:15476422

  17. Why don't we stop tuberculosis?

    PubMed

    Platt, A E

    1994-01-01

    Many people think of tuberculosis (TB) as a disease of the past of no current concern to modern society. This is not the case. Despite the medical establishment's ability to treat and cure TB, the disease has reemerged to assume the position as the leading killer worldwide among infectious or communicable diseases. TB threatens more people than AIDS, cholera, dengue fever, and other infectious diseases combined. Accordingly, the World Health Organization (WHO) declared a global state of emergency against TB in 1993. In 1993, 2.7 million people died from TB and another 8.1 million were infected. Worldwide, an estimated 1.7 billion people had inert TB infections. The current TB epidemic is expected to worsen, especially in the developing world due to the evolution of multi-drug-resistant strains and the emergence of AIDS which compromises human immune systems and makes them more susceptible to infectious diseases. By the year 2000, the global incidence of TB is expected to increase to 10.2 million cases per year, an increase of 36% over 1990's 7.5 million cases. 75% of the increase can be traced to poor TB control programs, population growth, and the advancing age of the population, while the remaining 25% is attributed to the interaction between the TB virus and HIV. More than 95% of TB cases reported in 1990 were in the developing world, with an estimated two thirds in Asia; India accounted for 2.1 million cases. Developing countries have a disproportionate number of cases because AIDS is spreading quickly, health services are inadequate, and little money is available for treatment. WHO points out that adherence to the complete and inexpensive drug regimen of rifampicin, isoniazid, pyrazinamide, and ethambutol every day for six to eight months could reduce the rate of TB transmission and cut the number of TB deaths in half over the next ten years. Worldwide early treatment could prevent almost 12 million deaths over the next decade and save large amounts of money

  18. Mycobacterium tuberculosis Pathogenesis and Molecular Determinants of Virulence

    PubMed Central

    Smith, Issar

    2003-01-01

    Tuberculosis (TB), one of the oldest known human diseases. is still is one of the major causes of mortality, since two million people die each year from this malady. TB has many manifestations, affecting bone, the central nervous system, and many other organ systems, but it is primarily a pulmonary disease that is initiated by the deposition of Mycobacterium tuberculosis, contained in aerosol droplets, onto lung alveolar surfaces. From this point, the progression of the disease can have several outcomes, determined largely by the response of the host immune system. The efficacy of this response is affected by intrinsic factors such as the genetics of the immune system as well as extrinsic factors, e.g., insults to the immune system and the nutritional and physiological state of the host. In addition, the pathogen may play a role in disease progression since some M. tuberculosis strains are reportedly more virulent than others, as defined by increased transmissibility as well as being associated with higher morbidity and mortality in infected individuals. Despite the widespread use of an attenuated live vaccine and several antibiotics, there is more TB than ever before, requiring new vaccines and drugs and more specific and rapid diagnostics. Researchers are utilizing information obtained from the complete sequence of the M. tuberculosis genome and from new genetic and physiological methods to identify targets in M. tuberculosis that will aid in the development of these sorely needed antitubercular agents. PMID:12857778

  19. Tuberculosis--advances in development of new drugs, treatment regimens, host-directed therapies, and biomarkers.

    PubMed

    Wallis, Robert S; Maeurer, Markus; Mwaba, Peter; Chakaya, Jeremiah; Rustomjee, Roxana; Migliori, Giovanni Battista; Marais, Ben; Schito, Marco; Churchyard, Gavin; Swaminathan, Soumya; Hoelscher, Michael; Zumla, Alimuddin

    2016-04-01

    Tuberculosis is the leading infectious cause of death worldwide, with 9·6 million cases and 1·5 million deaths reported in 2014. WHO estimates 480,000 cases of these were multidrug resistant (MDR). Less than half of patients who entered into treatment for MDR tuberculosis successfully completed that treatment, mainly due to high mortality and loss to follow-up. These in turn illustrate weaknesses in current treatment regimens and national tuberculosis programmes, coupled with operational treatment challenges. In this Review we provide an update on recent developments in the tuberculosis drug-development pipeline (including new and repurposed antimicrobials and host-directed drugs) as they are applied to new regimens to shorten and improve outcomes of tuberculosis treatment. Several new or repurposed antimicrobial drugs are in advanced trial stages for MDR tuberculosis, and two new antimicrobial drug candidates are in early-stage trials. Several trials to reduce the duration of therapy in MDR and drug-susceptible tuberculosis are ongoing. A wide range of candidate host-directed therapies are being developed to accelerate eradication of infection, prevent new drug resistance, and prevent permanent lung injury. As these drugs have been approved for other clinical indications, they are now ready for repurposing for tuberculosis in phase 2 clinical trials. We assess risks associated with evaluation of new treatment regimens, and highlight opportunities to advance tuberculosis research generally through regulatory innovation in MDR tuberculosis. Progress in tuberculosis-specific biomarkers (including culture conversion, PET and CT imaging, and gene expression profiles) can support this innovation. Several global initiatives now provide unique opportunities to tackle the tuberculosis epidemic through collaborative partnerships between high-income countries and middle-income and low-income countries for clinical trials training and research, allowing funders to

  20. [Tuberculosis in Iceland. 1976].

    PubMed

    Sigurdsson, Sigurdur

    2005-01-01

    Because of signs of tuberculous lesions in old skeletons it can be stated with certainty that tuberculosis has occurred in the country shortly after the settlement. From that time and up to the seventeenth century, little or nothing is known about the occurrence of the disease. A few preserved descriptions of diseases and deaths indicate that tuberculosis has existed in the country before the advent of qualified physicians in 1760. On the basis of papers and reports from the first physicians and the first tuberculosis registers the opinions is set forth that the disease has been rare up to the latter part of the nineteenth century. During the two last decades of that century the disease began to spread more rapidly and increased steadily up to the turn of the century. Although reporting of the disease was started in the last decade of the nineteenth century the reporting was first ordered by law with the passage of the first tuberculosis Act in the year 1903. With this legislation official measures for tuberculosis control work really started in the country. The first sanatorium was built in 1910. In 1921 the tuberculosis Act was revised and since then practically all the expenses for the hospitalization and treatment of tuberculous cases has been defrayed by the state. In the year 1935 organized tuberculosis control work was begun and a special physician appointed to direct it. From then on systematic surveys were made, partly in health centers i.e. tuberculosis clinics, which were established in the main towns, and partly by means of transportable X ray units in outlying rural areas of the country. In 1939 the tuberculosis Act was again revised with special reference to the surveys and the activities of the tuberculosis clinics. This act is still in force. Some items of it are described. The procedure of the surveys and the methods of examination are described. The great majority of subjects were tuberculin tested and all positive reactors X rayed. Furthermore, X

  1. Highly active antiretroviral treatment for the prevention of HIV transmission

    PubMed Central

    2010-01-01

    In 2007 an estimated 33 million people were living with HIV; 67% resided in sub-Saharan Africa, with 35% in eight countries alone. In 2007, there were about 1.4 million HIV-positive tuberculosis cases. Globally, approximately 4 million people had been given highly active antiretroviral therapy (HAART) by the end of 2008, but in 2007, an estimated 6.7 million were still in need of HAART and 2.7 million more became infected with HIV. Although there has been unprecedented investment in confronting HIV/AIDS - the Joint United Nations Programme on HIV/AIDS estimates $13.8 billion was spent in 2008 - a key challenge is how to address the HIV/AIDS epidemic given limited and potentially shrinking resources. Economic disparities may further exacerbate human rights issues and widen the increasingly divergent approaches to HIV prevention, care and treatment. HIV transmission only occurs from people with HIV, and viral load is the single greatest risk factor for all modes of transmission. HAART can lower viral load to nearly undetectable levels. Prevention of mother to child transmission offers proof of the concept of HAART interrupting transmission, and observational studies and previous modelling work support using HAART for prevention. Although knowing one's HIV status is key for prevention efforts, it is not known with certainty when to start HAART. Building on previous modelling work, we used an HIV/AIDS epidemic of South African intensity to explore the impact of testing all adults annually and starting persons on HAART immediately after they are diagnosed as HIV positive. This theoretical strategy would reduce annual HIV incidence and mortality to less than one case per 1000 people within 10 years and it would reduce the prevalence of HIV to less than 1% within 50 years. To explore HAART as a prevention strategy, we recommend further discussions to explore human rights and ethical considerations, clarify research priorities and review feasibility and acceptability

  2. Quantification of Shared Air: A Social and Environmental Determinant of Airborne Disease Transmission

    PubMed Central

    Wood, Robin; Morrow, Carl; Ginsberg, Samuel; Piccoli, Elizabeth; Kalil, Darryl; Sassi, Angelina; Walensky, Rochelle P.; Andrews, Jason R.

    2014-01-01

    Background Tuberculosis is endemic in Cape Town, South Africa where a majority of the population become tuberculosis infected before adulthood. While social contact patterns impacting tuberculosis and other respiratory disease spread have been studied, the environmental determinants driving airborne transmission have not been quantified. Methods Indoor carbon dioxide levels above outdoor levels reflect the balance of exhaled breath by room occupants and ventilation. We developed a portable monitor to continuously sample carbon dioxide levels, which were combined with social contact diary records to estimate daily rebreathed litres. A pilot study established the practicality of monitor use up to 48-hours. We then estimated the daily volumes of air rebreathed by adolescents living in a crowded township. Results One hundred eight daily records were obtained from 63 adolescents aged between 12- and 20-years. Forty-five lived in wooden shacks and 18 in brick-built homes with a median household of 4 members (range 2–9). Mean daily volume of rebreathed air was 120.6 (standard error: 8.0) litres/day, with location contributions from household (48%), school (44%), visited households (4%), transport (0.5%) and other locations (3.4%). Independent predictors of daily rebreathed volumes included household type (p = 0.002), number of household occupants (p = 0.021), number of sleeping space occupants (p = 0.022) and winter season (p<0.001). Conclusions We demonstrated the practical measurement of carbon dioxide levels to which individuals are exposed in a sequence of non-steady state indoor environments. A novel metric of rebreathed air volume reflects social and environmental factors associated with airborne infection and can identify locations with high transmission potential. PMID:25181526

  3. Extensively drug-resistant tuberculosis.

    PubMed

    Jassal, Mandeep; Bishai, William R

    2009-01-01

    Extensively drug-resistant (XDR) tuberculosis is defined as disease caused by Mycobacterium tuberculosis with resistance to at least isoniazid and rifampicin, any fluoroquinolone, and at least one of three injectable second-line drugs (amikacin, capreomycin, or kanamycin). The definition has applicable clinical value and has allowed for more uniform surveillance in varied international settings. Recent surveillance data have indicated that the prevalence of tuberculosis drug resistance has risen to the highest rate ever recorded. The gold standard for drug-susceptibility testing has been the agar proportion method; however, this technique requires several weeks for results to be determined. More sensitive and specific diagnostic tests are still unavailable in resource-limited settings. Clinical manifestations, although variable in different settings and among different strains, have in general shown that XDR tuberculosis is associated with greater morbidity and mortality than non-XDR tuberculosis. The treatment of XDR tuberculosis should include agents to which the organism is susceptible, and should continue for a minimum of 18-24 months. However, treatment continues to be limited in tuberculosis-endemic countries largely because of weaknesses in national tuberculosis health-care models. The ultimate strategy to control drug-resistant tuberculosis is one that implements a comprehensive approach incorporating innovation from the political, social, economic, and scientific realms. PMID:18990610

  4. Maxillary sinusitis with pulmonary tuberculosis

    PubMed Central

    Upadhyay, Rashmi; Prakash, Ved; Singh, Abhishek Bahadur; Saheer, S

    2014-01-01

    Tubercular infection of the nasal cavity is an infrequently encountered condition. More so, after the discovery of relevant antibiotics, nasal sinus tuberculosis is not commonly seen. Few cases have reported tuberculosis of the paranasal sinuses, nasopharynx and larynx. With the increasing incidence of HIV, these rare forms of infection have started re-emerging. We present a case of a middle aged man presenting with nasal cavity lesion along with pulmonary tuberculosis, which came to light only after the diagnosis of maxillary sinus tuberculosis. PMID:25085948

  5. Pathology of post primary tuberculosis of the lung: an illustrated critical review.

    PubMed

    Hunter, Robert L

    2011-11-01

    Post primary tuberculosis occurs in immunocompetent adults, is restricted to the lungs and accounts for 80% of all clinical cases and nearly 100% of transmission of infection. The supply of human tissues with post primary tuberculosis plummeted with the introduction of antibiotics decades before the flowering of research using molecular methods in animal models. Unfortunately, the paucity of human tissues prevented validation of the models. As a result, it is a paradigm of contemporary research that caseating granulomas are the characteristic lesion of all tuberculosis and that cavities form when they erode into bronchi. This differs from descriptions of the preantibiotic era when many investigators had access to thousands of cases. They reported that post primary tuberculosis begins as an exudative reaction: a tuberculous lipid pneumonia of foamy alveolar macrophages that undergoes caseation necrosis and fragmentation to produce cavities. Granulomas in post primary disease arise only in response to old caseous pneumonia and produce fibrosis, not cavities. We confirmed and extended these observations with study of 104 cases of untreated tuberculosis. In addition, studies of the lungs of infants and immunosuppressed adults revealed a second type of tuberculous pneumonia that seldom produces cavities. Since the concept that cavities arise from caseating granulomas was supported by studies of animals infected with Mycobacterium bovis, we investigated its pathology. We found that M. bovis does not produce post primary tuberculosis in any species. It only produces an aggressive primary tuberculosis that can develop small cavities by erosion of caseating granulomas. Consequently, a key unresolved question in the pathogenesis of tuberculosis is identification of the mechanisms by which Mycobacterium tuberculosis establish a localized safe haven in alveolar macrophages in an otherwise solidly immune host where it can develop conditions for formation of cavities and

  6. Eliminating bovine tuberculosis in cattle and badgers: insight from a dynamic model

    PubMed Central

    Brooks-Pollock, Ellen; Wood, James L. N.

    2015-01-01

    Bovine tuberculosis (BTB) is a multi-species infection that commonly affects cattle and badgers in Great Britain. Despite years of study, the impact of badgers on BTB incidence in cattle is poorly understood. Using a two-host transmission model of BTB in cattle and badgers, we find that published data and parameter estimates are most consistent with a system at the threshold of control. The most consistent explanation for data obtained from cattle and badger populations includes within-host reproduction numbers close to 1 and between-host reproduction numbers of approximately 0.05. In terms of controlling infection in cattle, reducing cattle-to-cattle transmission is essential. In some regions, even large reductions in badger prevalence can have a modest impact on cattle infection and a multi-stranded approach is necessary that also targets badger-to-cattle transmission directly. The new perspective highlighted by this two-host approach provides insight into the control of BTB in Great Britain. PMID:25972466

  7. Clustered Tuberculosis in a Low-Burden Country: Nationwide Genotyping through 15 Years

    PubMed Central

    Andersen, A. B.; Kok-Jensen, A.; Bygbjerg, I. C.; Andersen, P. H.; Thomsen, V. O.; Kamper-Jørgensen, M.; Lillebaek, T.

    2012-01-01

    Molecular genotyping of Mycobacterium tuberculosis has proved to be a powerful tool in tuberculosis surveillance, epidemiology, and control. Based on results obtained through 15 years of nationwide IS6110 restriction fragment length polymorphism (RFLP) genotyping of M. tuberculosis cases in Denmark, a country on the way toward tuberculosis elimination, we discuss M. tuberculosis transmission dynamics and point to areas for control interventions. Cases with 100% identical genotypes (RFLP patterns) were defined as clustered, and a cluster was defined as cases with an identical genotype. Of 4,601 included cases, corresponding to 76% of reported and 97% of culture-verified tuberculosis cases in the country, 56% were clustered, of which 69% were Danes. Generally, Danes were more often in large clusters (≥50 persons), older (mean age, 45 years), and male (male/female ratio, 2.5). Also, Danes had a higher cluster frequency within a 2-year observation window (60.8%), and higher clustering rate of new patterns over time, compared to immigrants. A dominant genotype, cluster 2, constituted 44% of all clustered and 35% of all genotyped cases. This cluster was primarily found among Danish males, 30 to 59 years of age, often socially marginalized, and with records of alcohol abuse. In Danes, cluster 2 alone was responsible for the high cluster frequency level. Immigrants had a higher incidence of clustered tuberculosis at a younger age (0 to 39 years). To achieve tuberculosis elimination in Denmark, high-risk transmission environments, like the cluster 2 enviornment in Danes, and specific transmission chains in immigrants in the capital area, e.g., homeless/socially marginalized Somalis/Greenlanders, often with alcohol abuse, must be targeted, including groups with a high risk of reactivation. PMID:22675129

  8. Tuberculosis of spine

    PubMed Central

    Agrawal, Vinod; Patgaonkar, P. R.; Nagariya, S. P.

    2010-01-01

    Tuberculosis of the spine is one of the most common spine pathology in India. Over last 4 decades a lot has changed in the diagnosis, medical treatment and surgical procedures to treat this disorder. Further developments in diagnosis using molecular genetic techniques, more effective antibiotics and more aggressive surgical protocols have become essential with emergence of multidrug resistant TB. Surgical procedures such as single stage anterior and posterior stabilization, extrapleral dorsal spine anterior stabilization and endoscopic thoracoscopic surgeries have reduced the mortality and morbidity of the surgical procedures. is rapidly progressing. It is a challenge to treat MDR-TB Spine with late onset paraplegia and progressive deformity. Physicians must treat tuberculosis of spine on the basis of Culture and sensitivity. PMID:21572628

  9. Yield of Contact Investigations in Households of Patients With Drug-Resistant Tuberculosis: Systematic Review and Meta-Analysis

    PubMed Central

    Shah, N. Sarita; Yuen, Courtney M.; Heo, Moonseong; Tolman, Arielle W.; Becerra, Mercedes C.

    2014-01-01

    Contact investigations among individuals living with drug-susceptible tuberculosis patients (source cases) have shown a high yield of tuberculosis disease and latent tuberculosis, but the yield of such investigations in households of drug-resistant tuberculosis source cases is unknown. In this systematic review and meta-analysis, we found 25 studies that evaluated a median of 111 (interquartile range, 21–302) household contacts of drug-resistant tuberculosis source cases. The pooled yield was 7.8% (95% CI, 5.6%–10.0%) for active tuberculosis and 47.2% (95% CI, 30.0%–61.4%) for latent tuberculosis, although there was significant statistical heterogeneity (P < .0001). More than 50% of secondary cases with drug susceptibility test results were concordant with those of the source case. Among studies that followed household members, the majority of secondary cases were detected within 1 year of the source case's diagnosis. Household contact investigation around drug-resistant tuberculosis patients is a high-yield intervention for detection of drug-resistant tuberculosis and prevention of ongoing transmission. PMID:24065336

  10. Feral ferrets (Mustela furo) as hosts and sentinels of tuberculosis in New Zealand

    PubMed Central

    Byrom, AE; Caley, P; Paterson, BM; Nugent, G

    2015-01-01

    Abstract The control and eventual eradication of bovine tuberculosis (TB) poses major challenges in New Zealand, given the variety of wildlife species susceptible to TB, many of which are capable of onwards transmission of Mycobacterium bovis infection. Here we discuss the role of feral ferrets (Mustela furo), focussing on potential transmission or risk pathways that have implications for management of TB. Firstly inter-specific transmission to ferrets. Ferrets scavenge potentially infected wildlife, including other ferrets, thus prevalence of TB can be amplified through ferrets feeding on tuberculous carcasses, particularly brushtail possums (Trichosurus vulpecula). Secondly intra-specific transmission between ferrets. The rate of ferret-ferret transmission depends on population density, and in some places ferret densities exceed the estimated threshold for disease persistence. TB can therefore potentially be maintained independently of other sources of infection. Thirdly transmission from ferrets to other wildlife. These include the main wildlife maintenance host, brushtail possums, that will occasionally scavenge potentially tuberculous ferret carcasses. Fourthly transmission from ferrets to livestock. This is considered to occur occasionally, but the actual rate of transmission has never been measured. Fifthly geographical spread. M. bovis-infected ferrets can travel large distances and cause new outbreaks of TB at locations previously free of TB, which may have caused an expansion of TB-endemic areas.Ferrets play a complex role in the TB cycle in New Zealand; they are capable of contracting, amplifying and transmitting M. bovis infection, sometimes resulting in ferret populations with a high prevalence of TB. However, ferret population densities are usually too low to sustain infection independently, and transmission to other wildlife or livestock appears a rarer event than with possums. Nevertheless, management of ferrets remains a key part of the National

  11. Investments in tuberculosis research - what are the gaps?

    PubMed

    Khan, Mishal S; Fletcher, Helen; Coker, Richard

    2016-01-01

    Through decades of research, numerous studies have generated robust evidence about effective interventions for tuberculosis control. Yet, the global annual decline in incidence of approximately 1 % is evidence that current approaches and investment strategies are not sufficient. In this article, we assess recent tuberculosis research funding and discuss two critical gaps in funding and in scientific evidence from topics that have been left off the research priority agenda.We first examine research and development funding goals in the 2011-2015 Global Plan to Stop Tuberculosis and analyze disbursements to different research areas by funders worldwide in 2014. We then summarize, through a compilation of published literature and consultation with 35 researchers across multiple disciplines in the London School of Hygiene and Tropical Medicine TB Centre, priorities identified by the tuberculosis research community. Finally, we compare researchers' priority areas to the global funding agendas and activities.Our analysis shows that, among the five key research areas defined in the 2011-2015 Global Plan - namely drugs, basic science, vaccines, diagnostics and operational research - drug discovery and basic science on Mycobacterium tuberculosis accounted for 60 % of the $2 billion annual funding target. None of the research areas received the recommended level of funding. Operational research, which had the lowest target, received 66 % of its target funding, whereas new diagnostics received only 19 %. Although many of the priority research questions identified by researchers fell within the Global Plan categories, our analysis highlights important areas that are not explicitly mentioned in the current plan. These priority research areas included improved understanding of tuberculosis transmission dynamics, the role of social protection and social determinants, and health systems and policy research.While research priorities are increasingly important in light of the

  12. Tuberculosis in Sudan: a study of Mycobacterium tuberculosis strain genotype and susceptibility to anti-tuberculosis drugs

    PubMed Central

    2011-01-01

    Background Sudan is a large country with a diverse population and history of civil conflict. Poverty levels are high with a gross national income per capita of less than two thousand dollars. The country has a high burden of tuberculosis (TB) with an estimated 50,000 incident cases during 2009, when the estimated prevalence was 209 cases per 100,000 of the population. Few studies have been undertaken on TB in Sudan and the prevalence of drug resistant disease is not known. Methods In this study Mycobacterium tuberculosis isolates from 235 patients attending three treatment centers in Sudan were screened for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin by the proportion method on Lowenstein Jensen media. 232 isolates were also genotyped by spoligotyping. Demographic details of patients were recorded using a structured questionnaire. Statistical analyses were conducted to examine the associations between drug resistance with risk ratios computed for a set of risk factors (gender, age, case status - new or relapse, geographic origin of the patient, spoligotype, number of people per room, marital status and type of housing). Results Multi drug-resistant tuberculosis (MDR-TB), being resistance to at least rifampicin and isoniazid, was found in 5% (95% CI: 2,8) of new cases and 24% (95% CI: 14,34) of previously treated patients. Drug resistance was associated with previous treatment with risk ratios of 3.51 (95% CI: 2.69-4.60; p < 0.001) for resistance to any drug and 5.23 (95% CI: 2.30-11.90; p < 0.001) for MDR-TB. Resistance was also associated with the geographic region of origin of the patient, being most frequently observed in patients from the Northern region and least in the Eastern region with risk ratios of 7.43 (95%CI:3.42,16.18; p: < 0.001) and 14.09 (95%CI:1.80,110.53; p:0.026) for resistance to any drug and MDR-TB. The major genotype observed was of the Central Asia spoligotype family (CAS1_Delhi), representing 49% of the 232 isolates

  13. Tuberculosis control learning games.

    PubMed

    Smith, I

    1993-07-01

    In teaching health workers about tuberculosis (TB) control we frequently concentrate on the technological aspects, such as diagnosis, treatment and recording. Health workers also need to understand the sociological aspects of TB control, particularly those that influence the likelihood of diagnosis and cure. Two games are presented that help health workers comprehend the reasons why TB patients often delay in presenting for diagnosis, and why they then frequently default from treatment. PMID:8356734

  14. Diagnostics for pulmonary tuberculosis.

    PubMed

    Cudahy, Patrick; Shenoi, Sheela V

    2016-04-01

    Tuberculosis (TB) remains a leading cause of human suffering and mortality despite decades of effective treatment being available. Accurate and timely diagnosis remains an unmet goal. The HIV epidemic has also led to new challenges in the diagnosis of TB. Several new developments in TB diagnostics have the potential to positively influence the global campaign against TB. We aim to review the performance of both established as well as new diagnostics for pulmonary TB in adults, and discuss the ongoing challenges. PMID:27005271

  15. Diagnostics for pulmonary tuberculosis

    PubMed Central

    Cudahy, Patrick

    2016-01-01

    Tuberculosis (TB) remains a leading cause of human suffering and mortality despite decades of effective treatment being available. Accurate and timely diagnosis remains an unmet goal. The HIV epidemic has also led to new challenges in the diagnosis of TB. Several new developments in TB diagnostics have the potential to positively influence the global campaign against TB. We aim to review the performance of both established as well as new diagnostics for pulmonary TB in adults, and discuss the ongoing challenges. PMID:27005271

  16. John Keats and tuberculosis.

    PubMed

    Radetsky, M

    2001-05-01

    John Keats was trained as an apothecary, the general practitioner of the day. Precocious in his sensibilities and fluent in his imagery, he also was the model of the romantic poet. That he was a physician and a poet makes his early death from tuberculosis poignant and revealing. This history traces his life and death against the backdrop of medicine at the turn of the 19th century. PMID:11368115

  17. Detection of Tuberculosis Infection Hotspots Using Activity Spaces Based Spatial Approach in an Urban Tokyo, from 2003 to 2011

    PubMed Central

    Izumi, Kiyohiko; Ohkado, Akihiro; Uchimura, Kazuhiro; Murase, Yoshiro; Tatsumi, Yuriko; Kayebeta, Aya; Watanabe, Yu; Ishikawa, Nobukatsu

    2015-01-01

    Background Identifying ongoing tuberculosis infection sites is crucial for breaking chains of transmission in tuberculosis-prevalent urban areas. Previous studies have pointed out that detection of local accumulation of tuberculosis patients based on their residential addresses may be limited by a lack of matching between residences and tuberculosis infection sites. This study aimed to identify possible tuberculosis hotspots using TB genotype clustering statuses and a concept of “activity space”, a place where patients spend most of their waking hours. We further compared the spatial distribution by different residential statuses and describe urban environmental features of the detected hotspots. Methods Culture-positive tuberculosis patients notified to Shinjuku city from 2003 to 2011 were enrolled in this case-based cross-sectional study, and their demographic and clinical information, TB genotype clustering statuses, and activity space were collected. Spatial statistics (Global Moran’s I and Getis-Ord Gi* statistics) identified significant hotspots in 152 census tracts, and urban environmental features and tuberculosis patients’ characteristics in these hotspots were assessed. Results Of the enrolled 643 culture-positive tuberculosis patients, 416 (64.2%) were general inhabitants, 42 (6.5%) were foreign-born people, and 184 were homeless people (28.6%). The percentage of overall genotype clustering was 43.7%. Genotype-clustered general inhabitants and homeless people formed significant hotspots around a major railway station, whereas the non-clustered general inhabitants formed no hotspots. This suggested the detected hotspots of activity spaces may reflect ongoing tuberculosis transmission sites and were characterized by smaller residential floor size and a higher proportion of non-working households. Conclusions Activity space-based spatial analysis suggested possible TB transmission sites around the major railway station and it can assist in further

  18. Shingles Transmission

    MedlinePlus

    ... on Shingles Immunization Action Coalition Chickenpox Q&As Transmission Language: English Español (Spanish) Recommend on Facebook Tweet ... Prevention & Treatment Related Pages Preventing Varicella Zoster Virus Transmission in Healthcare Settings Related Links Medline Plus NIH ...

  19. [Tuberculosis. Future perspectives].

    PubMed

    Marques Gomes, M João

    2004-01-01

    Tuberculosis remains a major health problem around the world and its incidence is growing 0.4% each year. There are 2 billions of infected, 8.4 millions new cases every year and 16 million patients. The association of VIH and tuberculosis, the increasing number of multidrug resistance, failure of health systems, greater mobility of people, poverty, wars and social exclusion, are the major causes of the epidemiological situation. Faster, more specific and sensible diagnostic methods are being investigated. Some of them use molecular biology techniques, some uses radioisotopes and some others are based on colour and fluorescence modifications of dyes. New drugs, new routes of administration and ways for increasing compliance are under investigation. More potent drugs, with greater biodisponibility and adequate pharmacokinetics for shorter treatments for multidrug and latent forms of bacilli are needed. New vaccines are under investigations, namely Adjuvant Subunits Vaccines, DNA Vaccines DNA, no micobacterianos vectors, and attenuated living vaccines are being tested. Finally some considerations are made concerning the need of global committement to win the fight against tuberculosis in the near future. PMID:15202032

  20. Tuberculosis in leprosy patients detected between 1902 and 1991 in French Polynesia.

    PubMed

    Glaziou, P; Cartel, J L; Moulia-Pelat, J P; Ngoc, L N; Chanteau, S; Plichart, R; Grosset, J H

    1993-06-01

    From 1902 onward, notification and follow up of leprosy patients has been systematic in French Polynesia. Since 1960, a tuberculosis control program and a register has also been implemented. From 1902 to 1959, 673 cases of leprosy were detected [346 multibacillary (MB), 138 paucibacillary (PB), and 179 unclassified due to the loss of medical files by the time of classification which was done during the 1980s]. Of these 673 cases, 89 (13.2%) died from tuberculosis, giving a mean annual death rate of tuberculosis in leprosy patients of 232 per 100,000. Mortality from tuberculosis in leprosy patients detected between 1901 and 1930 was 20.7%, and decreased to 8.04% in patients detected from 1931 to 1959. In total, it was estimated that 26.4% of the leprosy cases had developed tuberculosis. From 1960 to 1991, 350 new cases of leprosy were detected (141 MB, 209 PB). Of them, 12 (3.4%) developed tuberculosis (7 before detection of leprosy, 5 after detection of leprosy). The dramatic decrease of the proportion of leprosy patients who developed tuberculosis between the periods 1902-1959 (26.4%) and 1960-1991 (3.4%) might be related to the important decline of the tuberculosis situation since 1960. From 1902 to 1959, mortality from tuberculosis occurred significantly more frequently in MB patients (13%) than in PB patients [4%, relative risk (RR) = 3.21, p = 0.003]. From 1960 to 1991, the incidence of tuberculosis seemed more frequent in MB patients (RR = 2.96, p = 0.07) whatever the sequence of detection of the two diseases. Our study suggests that lepromatous patients could share factors of susceptibility to mycobacterial diseases with patients developing tuberculosis. PMID:8371028

  1. Molecular Epidemiology of Mycobacterium tuberculosis Complex in Singapore, 2006-2012

    PubMed Central

    Win, Wah; Chee, Cynthia Bin-Eng; Hsu, Li Yang; Mak, Estelle; Earnest, Arul; Ong, Marcus Eng-Hock; Cutter, Jeffery; Wang, Yee Tang

    2013-01-01

    Background Tuberculosis remains common in Singapore, increasing in incidence since 2008. We attempted to determine the molecular epidemiology of Mycobacterium tuberculosis complex (MTC) isolates locally, identifying major circulating genotypes and obtaining a glimpse of transmission dynamics. Methodology Non-duplicate MTC isolates archived between 2006 and 2012 at the larger clinical tuberculosis laboratory in Singapore were sampled for spoligotyping and MIRU-VNTR typing, with case data obtained from the Singapore Tuberculosis Elimination Program registry database. Isolates between 2008 and 2012 were selected because of either multidrug-resistance or potential epidemiological linkage, whereas earlier isolates were randomly selected. Separate analyses were performed for the early (2006-2007) and later (2008-2012) study phases in view of potential selection bias. Principal Findings A total of 1,612 MTC isolates were typed, constituting 13.1% of all culture-positive tuberculosis cases during this period. Multidrug-resistance was present in 91 (5.6%) isolates – higher than the national prevalence in view of selection bias. The majority of isolates belonged to the Beijing (45.8%) and EAI (22.8%) lineages. There were 347 (30.7%) and 133 (27.5%) cases clustered by combined spoligotyping and MIRU-VNTR typing from the earlier and later phases respectively. Patients within these clusters tended to be of Chinese ethnicity, Singapore resident, and have isolates belonging to the Beijing lineage. A review of prior contact investigation results for all patients with clustered isolates failed to reveal epidemiological links for the majority, suggesting either unknown transmission networks or inadequate specificity of the molecular typing methods in a country with a moderate incidence of tuberculosis. Conclusion Our work demonstrates that Singapore has a large and heterogeneous distribution of MTC strains, and with possible cross-transmission over the past few years based on our

  2. Method of joint frame synchronization and data-aided channel estimation for 100-Gb/s polarization-division multiplexing-single carrier frequency domain equalization coherent optical transmission systems

    NASA Astrophysics Data System (ADS)

    Cheng, Yun; Tan, Jun; Liu, Liu; He, Jing; Tang, Jin; Chen, Lin; Zhang, Jun; Li, Qiang; Xiao, Minlei

    2016-02-01

    To improve the performance of channel estimation (CE), a method of joint frame synchronization and data-aided CE using less training overhead is proposed. A 100-Gb/s polarization-division multiplexing coherent transmission system with quaternary phase-shift keying based on the proposed method is demonstrated by simulation. The simulation results show that the proposed method could achieve accurate timing offset and CE in the presence of strong amplified spontaneous emission noise.

  3. Tuberculosis Endometritis Presenting as A Leiomyoma

    PubMed Central

    Shirazi, Mahboobeh; Shahbazi, Fatemeh; Pirzadeh, Leila; Mohammadi, Seyed Rahim; Ghaffari, Parisa; Eftekhar, Tahereh

    2015-01-01

    Genitourinary tuberculosis is a common extrapulmonary manifestation of tuberculosis. Taking into consideration that genitourinary tuberculosis may be associated with a diversity of presentations, its diagnoses may be difficult. A young woman with an initial presumptive diagnosis of a uterine leiomyoma presented with abdominal pain and a pelvic mass that after further investigations, she was diagnosed with genital tuberculosis. PMID:25780530

  4. Noninvasive Test for Tuberculosis Detection among Primates

    PubMed Central

    Mugisha, Lawrence; Shoyama, Fernanda Miyagaki; O’Malley, Melanie J.; Flynn, JoAnne L.; Asiimwe, Benon; Travis, Dominic A.; Singer, Randall S.; Sreevatsan, Srinand

    2015-01-01

    Traditional testing methods have limited epidemiologic studies of tuberculosis among free-living primates. PCR amplification of insertion element IS6110 of Mycobacterium tuberculosis from fecal samples was evaluated as a noninvasive screening test for tuberculosis in primates. Active tuberculosis was detected among inoculated macaques and naturally exposed chimpanzees, demonstrating the utility of this test. PMID:25695329

  5. TUBERCULOSIS AND LUNG CANCER.

    PubMed

    Tamura, Atsuhisa

    2016-01-01

    The occurrence of pulmonary tuberculosis (PTB) and lung cancer as comorbidities has been extensively discussed in many studies. In the past, it was well known that lung cancer is a specific epidemiological successor of PTB and that lung cancer often develops in scars caused by PTB. In recent years, the relevance of the two diseases has drawn attention in terms of the close epidemiological connection and chronic inflammation-associated carcinogenesis. In Japanese case series studies, most lung cancer patients with tuberculous sequelae received supportive care alone in the past, but more recently, the use of aggressive lung cancer treatment is increasing. Many studies on PTB and lung cancer as comorbidities have revealed that active PTB is noted in 2-5% of lung cancer cases, whereas lung cancer is noted in 1-2% of active PTB cases. In such instances of comorbidity, many active PTB cases showed Type II (non-extensively cavitary disease) and Spread 2-3 (intermediate-extensive diseases) on chest X-rays, but standard anti-tuberculosis treatment easily eradicates negative conversion of sputum culture for M. tuberculosis; lung cancer cases were often stage III- IV and squamous cell carcinoma predominant, and the administration of aggressive treatment for lung cancer is increasing. The major clinical problems associated with PTB and lung cancer as comorbidities include delay in diagnosis (doctor's delay) and therapeutic limitations. The former involves two factors of radiographic interpretation: the principles of parsimony (Occam's razor) and visual search; the latter involves three factors of lung cancer treatment: infectivity of M.tuberculosis, anatomical limitation due to lung damage by tuberculosis, and drug-drug interactions between rifampicin and anti-cancer drugs, especially molecularly targeted drugs. The comorbidity of these two diseases is an important health-related issue in Japan. In the treatment of PTB, the possibility of concurrent lung cancer should be kept

  6. Tuberculosis of the parotid gland.

    PubMed

    Iserì, Mete; Aydìner, Omer; Celìk, Levent; Peker, Onder

    2005-04-01

    Tuberculosis of the parotid gland is very rare and clinically indistinguishable from a neoplasm. Thus the diagnosis of parotid gland involvement with tuberculosis has traditionally been made after surgical resection. We present a case which was diagnosed on fine needle aspiration cytology and managed medically. PMID:15949089

  7. Tuberculosis of the pubic symphysis

    PubMed Central

    Gothwal, Sudarshan; Varshney, Peeyush; Mathur, Shivank; Songra, Bhupen

    2014-01-01

    Tuberculosis is one of India’s public health problems. It involves various systems of the body, including the skeletal system. Osteoarticular tuberculosis is the second most common form of extrapulmonary tuberculosis next to lymph nodes and constitutes about 13% of all extrapulmonary cases. It is generally accepted that osteoarticular tuberculosis is the result of a haematogenous or lymphatic spread from a reactivated latent focus, usually pulmonary; however, previous infection is not always encountered, and in only 40–50% of the cases, it is possible to demonstrate another active infection site. The commonest site for skeletal tuberculosis is the spine followed by the hip, knee and ankle joints. Tuberculosis can involve literally any bone or joint. Pubic symphysis is an uncommon site for tuberculosis in the case of the skeletal system. We present a rare case of pubic symphysis tuberculosis in a 25-year-old woman presented to the general surgical department with a swelling in the right thigh region. PMID:24515233

  8. Outbreak of Tuberculosis Among Guatemalan Immigrants in Rural Minnesota, 2008

    PubMed Central

    Lowther, Sara A.; Miramontes, Roque; Navara, Barbara; Sabuwala, Nadya; Brueshaber, Milayna; Solarz, Sarah; Haddad, Maryam B.; Sodt, Deborah; Lynfield, Ruth

    2011-01-01

    Objectives We described the outbreak investigation and control measures after the Minnesota Department of Health identified a cluster of tuberculosis (TB) cases among Guatemalan immigrants within three rural Minnesota counties in August 2008. Methods TB cases were diagnosed by tuberculin skin test followed by chest radiography and sputum testing for Mycobacterium tuberculosis (M. tuberculosis). We reviewed medical records, interviewed patients, and completed a contact investigation for each infectious case. We used isolate genotyping to confirm epidemiologic links between cases. Results The index case was a six-month-old U.S.-born male with Guatemalan parents. Although he experienced four months of cough and fever, TB was not considered at two medical visits but was diagnosed upon hospitalization in May 2008. The presumed source of infection was a Guatemalan male aged 25 years who sang in a band that practiced in the infant’s house and whose pulmonary TB was diagnosed at hospitalization in June 2008, despite his having sought medical attention for symptoms seven months earlier. Among the 16 identified TB cases, 14 were outbreak-related. Three genetically distinct M. tuberculosis strains circulated. Of 150 contacts of the singer, 62 (41%) had latent TB infection and 13 (9%), including 10 children, had TB disease. Conclusions In this outbreak, delayed diagnoses contributed to M. tuberculosis transmission. Isolate genotyping corroborated the social links between outbreak-related patients. More timely diagnosis of TB among immigrants and their children can prevent TB transmission among communities in rural, low-incidence areas that might have limited resources for contact investigations. PMID:21886333

  9. Simultaneous detection and strain differentiation of Mycobacterium tuberculosis for diagnosis and epidemiology.

    PubMed Central

    Kamerbeek, J; Schouls, L; Kolk, A; van Agterveld, M; van Soolingen, D; Kuijper, S; Bunschoten, A; Molhuizen, H; Shaw, R; Goyal, M; van Embden, J

    1997-01-01

    Widespread use of DNA restriction fragment length polymorphism (RFLP) to differentiate strains of Mycobacterium tuberculosis to monitor the transmission of tuberculosis has been hampered by the need to culture this slow-growing organism and by the level of technical sophistication needed for RFLP typing. We have developed a simple method which allows simultaneous detection and typing of M. tuberculosis in clinical specimens and reduces the time between suspicion of the disease and typing from 1 or several months to 1 or 3 days. The method is based on polymorphism of the chromosomal DR locus, which contains a variable number of short direct repeats interspersed with nonrepetitive spacers. The method is referred to as spacer oligotyping or "spoligotyping" because it is based on strain-dependent hybridization patterns of in vitro-amplified DNA with multiple spacer oligonucleotides. Most of the clinical isolates tested showed unique hybridization patterns, whereas outbreak strains shared the same spoligotype. The types obtained from direct examination of clinical samples were identical to those obtained by using DNA from cultured M. tuberculosis. This novel preliminary study shows that the novel method may be a useful tool for rapid disclosure of linked outbreak cases in a community, in hospitals, or in other institutions and for monitoring of transmission of multidrug-resistant M. tuberculosis. Unexpectedly, spoligotyping was found to differentiate M. bovis from M. tuberculosis, a distinction which is often difficult to make by traditional methods. PMID:9157152

  10. Student Pharmacists as Tuberculosis Screeners

    PubMed Central

    Arnold, Jennifer

    2016-01-01

    Objective. To develop, implement, and evaluate a targeted educational module on tuberculosis screening with second-year professional pharmacy students that improves their knowledge, skills, and attitudes regarding tuberculosis screening. Design. A tuberculosis-screening educational module was developed in collaboration with the Washington State Pharmacy Association and Department of Health and incorporated in a core student pharmacist class. Students completed online didactic training and a live practicum, each lasting 90 minutes. Assessment. Students were assessed using a pre/postdidactic assessment, live practicum tuberculin skin testing (TST) administration and evaluation assessment, and postprogram written reflection. Student pre/postknowledge assessment scores improved in all areas except in documentation. Conclusion. The tuberculosis screening educational module significantly improved student knowledge, skills, and attitudes regarding tuberculosis screening. PMID:27073277

  11. Student Pharmacists as Tuberculosis Screeners.

    PubMed

    McKennon, Skye A; Arnold, Jennifer

    2016-03-25

    Objective. To develop, implement, and evaluate a targeted educational module on tuberculosis screening with second-year professional pharmacy students that improves their knowledge, skills, and attitudes regarding tuberculosis screening. Design. A tuberculosis-screening educational module was developed in collaboration with the Washington State Pharmacy Association and Department of Health and incorporated in a core student pharmacist class. Students completed online didactic training and a live practicum, each lasting 90 minutes. Assessment. Students were assessed using a pre/postdidactic assessment, live practicum tuberculin skin testing (TST) administration and evaluation assessment, and postprogram written reflection. Student pre/postknowledge assessment scores improved in all areas except in documentation. Conclusion. The tuberculosis screening educational module significantly improved student knowledge, skills, and attitudes regarding tuberculosis screening. PMID:27073277

  12. Transformative tools for tackling tuberculosis

    PubMed Central

    2015-01-01

    The world is in need of more effective approaches to controlling tuberculosis. The development of improved control strategies has been hampered by deficiencies in the tools available for detecting Mycobacterium tuberculosis and defining the dynamic consequences of the interaction of M. tuberculosis with its human host. Key needs include a highly sensitive, specific nonsputum diagnostic; biomarkers predictive of responses to therapy; correlates of risk for disease development; and host response–independent markers of M. tuberculosis infection. Tools able to sensitively detect and quantify total body M. tuberculosis burden might well be transformative across many needed use cases. Here, we review the current state of the field, paying particular attention to needed changes in experimental paradigms that would facilitate the discovery, validation, and development of such tools. PMID:26458772

  13. Genetic diversity of Mycobacterium tuberculosis isolated from tuberculosis patients in the Serengeti ecosystem in Tanzania

    PubMed Central

    Mbugi, Erasto V.; Katale, Bugwesa Z.; Siame, Keith K.; Keyyu, Julius D.; Kendall, Sharon L.; Dockrell, Hazel M.; Streicher, Elizabeth M.; Michel, Anita L.; Rweyemamu, Mark M.; Warren, Robin M.; Matee, Mecky I.; van Helden, Paul D.

    2015-01-01

    Summary This study was part of a larger cross-sectional survey that was evaluating tuberculosis (TB) infection in humans, livestock and wildlife in the Serengeti ecosystem in Tanzania. The study aimed at evaluating the genetic diversity of Mycobacterium tuberculosis isolates from TB patients attending health facilities in the Serengeti ecosystem. DNA was extracted from 214 sputum cultures obtained from consecutively enrolled newly diagnosed untreated TB patients aged ≥18 years. Spacer oligonucleotide typing (spoligotyping) and Mycobacterium Interspersed Repetitive Units and Variable Number Tandem Repeat (MIRU-VNTR) were used to genotype M. tuberculosis to establish the circulating lineages. Of the214 M. tuberculosis isolates genotyped, 55 (25.7%) belonged to the Central Asian (CAS) family, 52 (24.3%) were T family (an ill-defined family), 38 (17.8%) belonged to the Latin American Mediterranean (LAM) family, 25 (11.7%) to the East-African Indian (EAI) family, 25 (11.7%) comprised of different unassigned (‘Serengeti’) strain families, while 8 (3.7%) belonged to the Beijing family. A minority group that included Haarlem, X, U and S altogether accounted for 11 (5.2%) of all genotypes. MIRU-VNTR typing produced diverse patterns within and between families indicative of unlinked transmission chains. We conclude that, in the Serengeti ecosystem only a few successful families predominate namely CAS, T, LAM and EAI families. Other types found in lower prevalence are Beijing, Haarlem, X, S and MANU. The Haarlem, EAI_Somalia, LAM3 and S/convergent and X2 subfamilies found in this study were not reported in previous studies in Tanzania. PMID:25522841

  14. Single-Cell Elemental Analysis of Bacteria: Quantitative Analysis of Polyphosphates in Mycobacterium tuberculosis

    PubMed Central

    Ward, Sarah K.; Heintz, Joseph A.; Albrecht, Ralph M.; Talaat, Adel M.

    2012-01-01

    More than 1.8 million people die annually from infection with Mycobacterium tuberculosis, the causative agent of tuberculosis. The ability of M. tuberculosis to obtain and distribute micronutrients, including biometals, is known to play a role in its intracellular survival and virulence within a host. Techniques to detect elemental distributions within M. tuberculosis cells have previously been limited to bulk detection methods or low-resolution analyses. Here, we present a method for determining the elemental distribution within M. tuberculosis on a single-cell level, at high (individual nanometer) resolution, using scanning transmission electron microscopy (STEM) in concert with energy-dispersive X-ray spectroscopy (EDS). Results revealed the presence of large polyphosphate granules in all strains of Mycobacteria tested. These persisted even through starvation conditions, and might play a role connected to elemental homeostasis in M. tuberculosis. Associated with the polyphosphate granules were micronutrients such as calcium and magnesium. In addition, we expanded the technique beyond Mycobacteria to show that STEM and EDS could be used as a simple screen to detect the presence or absence of concentrated elements on a single-cell level within all six other bacterial types tested, with minimal processing to the bacteria. Overall, we believe that this technique represents a first step in developing a better understanding of the role that components of the intracellular milieu, including polyphosphates and biometals, play in the pathogenesis of M. tuberculosis, with potential future applications for in vivo analysis. PMID:22919654

  15. Active and latent tuberculosis among HIV-positive injecting drug users in Indonesia

    PubMed Central

    Meijerink, Hinta; Wisaksana, Rudi; Lestari, Mery; Meilana, Intan; Chaidir, Lydia; van der Ven, Andre JAM; Alisjahbana, Bachti; van Crevel, Reinout

    2015-01-01

    Introduction Injecting drug use (IDU) is associated with tuberculosis but few data are available from low-income settings. We examined IDU in relation to active and latent tuberculosis (LTBI) among HIV-positive individuals in Indonesia, which has a high burden of tuberculosis and a rapidly growing HIV epidemic strongly driven by IDU. Methods Active tuberculosis was measured prospectively among 1900 consecutive antiretroviral treatment (ART)-naïve adult patients entering care in a clinic in West Java. Prevalence of LTBI was determined cross-sectionally in a subset of 518 ART-experienced patients using an interferon-gamma release assay. Results Patients with a history of IDU (53.1%) more often reported a history of tuberculosis treatment (34.8% vs. 21.9%, p<0.001), more often received tuberculosis treatment during follow-up (adjusted HR=1.71; 95% CI: 1.25–2.35) and more often had bacteriologically confirmed tuberculosis (OR=1.67; 95% CI: 0.94–2.96). LTBI was equally prevalent among people with and without a history of IDU (29.1 vs. 30.4%, NS). The risk estimates did not change after adjustment for CD4 cell count or ART. Conclusions HIV-positive individuals with a history of IDU in Indonesia have more active tuberculosis, with similar rates of LTBI. Within the HIV clinic, LTBI screening and isoniazid preventive therapy may be prioritized to patients with a history of IDU. PMID:25690530

  16. Mathematical Model of Oxygen Transport in Tuberculosis Granulomas.

    PubMed

    Datta, Meenal; Via, Laura E; Chen, Wei; Baish, James W; Xu, Lei; Barry, Clifton E; Jain, Rakesh K

    2016-04-01

    Pulmonary granulomas-the hallmark of Mycobacterium tuberculosis (MTB) infection-are dense cellular lesions that often feature regions of hypoxia and necrosis, partially due to limited transport of oxygen. Low oxygen in granulomas can impair the host immune response, while MTB are able to adapt and persist in hypoxic environments. Here, we used a physiologically based mathematical model of oxygen diffusion and consumption to calculate oxygen profiles within the granuloma, assuming Michaelis-Menten kinetics. An approximate analytical solution-using a priori and newly estimated parameters from experimental data in a rabbit model of tuberculosis-was able to predict the size of hypoxic and necrotic regions in agreement with experimental results from the animal model. Such quantitative understanding of transport limitations can inform future tuberculosis therapeutic strategies that may include adjunct host-directed therapies that facilitate oxygen and drug delivery for more effective treatment. PMID:26253038

  17. Social and cultural factors in the successful control of tuberculosis.

    PubMed Central

    Rubel, A J; Garro, L C

    1992-01-01

    The burden of tuberculosis on the public health is staggering. Worldwide, annual incidence of new cases is estimated to be about 8 million. Almost 3 million deaths occur yearly. Early case identification and adherence to treatment regimens are the remaining barriers to successful control. In many nations, however, fewer than half those with active disease receive a diagnosis, and fewer than half those beginning treatment complete it. The twin problems of delay in seeking treatment and abandonment of a prescribed regimen derive from complex factors. People's confusion as to the implications of the tuberculosis symptoms, costs of transportation to clinic services, the social stigma that attaches to tuberculosis, the high cost of medication, organizational problems in providing adequate followup services, and patients' perception of clinic facilities as inhospitable all contribute to the complexity. Sociocultural factors are emphasized in this report because hitherto they have not been adequately explored. Salient among those sociocultural factors is the health culture of the patients. That is, the understanding and information people have from family, friends, and neighbors as to the nature of a health problem, its cause, and its implications. A knowledge of the health culture of their patients has become a critical tool if tuberculosis control programs are to be successful. Several anthropological procedures are recommended to help uncover the health culture of people served by tuberculosis clinics. PMID:1454974

  18. Tuberculosis peritonitis: gallium-67 scintigraphic appearance.

    PubMed

    Sumi, Y; Ozaki, Y; Hasegawa, H; Shindoh, N; Katayama, H; Tamamoto, F

    1999-06-01

    Tuberculosis peritonitis is a rare manifestation of extrapulmonary tuberculosis. The results of gallium-67 scintigraphy of three patients with tuberculosis peritonitis were reviewed to assess its usefulness in the diagnosis of this condition. Tuberculosis peritonitis was associated with diffuse or focal abdominal localization and decreased hepatic accumulation of gallium-67. These gallium-67 scan features of tuberculosis peritonitis may help to optimize the diagnosis and management of this disease. PMID:10435380

  19. Novel approaches to tuberculosis prevention: DNA vaccines.

    PubMed

    Rivas-Santiago, Bruno; Cervantes-Villagrana, Alberto R

    2014-03-01

    It is estimated that there are approximately eight million new cases of active tuberculosis (TB) worldwide annually. There is only 1 vaccine available for prevention: bacillus Calmette-Guérin (BCG). This has variable efficacy and is only protective for certain extrapulmonary TB cases in children, therefore new strategies for the creation of novel vaccines have emerged. One of the promising approaches is the DNA vaccine, used as a direct vaccination or as a prime-boost vaccine. This review describes the experimental data obtained during the design of DNA vaccines for TB. PMID:24450840

  20. Tuberculosis vaccines: barriers and prospects on the quest for a transformative tool

    PubMed Central

    Karp, Christopher L; Wilson, Christopher B; Stuart, Lynda M

    2015-01-01

    The road to a more efficacious vaccine that could be a truly transformative tool for decreasing tuberculosis morbidity and mortality, along with Mycobacterium tuberculosis transmission, is quite daunting. Despite this, there are reasons for optimism. Abetted by better conceptual clarity, clear acknowledgment of the degree of our current immunobiological ignorance, the availability of powerful new tools for dissecting the immunopathogenesis of human tuberculosis, the generation of more creative diversity in tuberculosis vaccine concepts, the development of better fit-for-purpose animal models, and the potential of more pragmatic approaches to the clinical testing of vaccine candidates, the field has promise for delivering novel tools for dealing with this worldwide scourge of poverty. PMID:25703572

  1. The ancient city of Rome, its empire, and the spread of tuberculosis in Europe.

    PubMed

    Eddy, Jared J

    2015-06-01

    The formation of the Roman Empire constituted an unprecedented joining of Mediterranean and European lands and peoples, centering on the capital of Rome. During the late Roman Republic and early Roman Empire (ca. 200B.C.-ca. 200 A.D.) urbanization and population growth led to conditions favorable to the spread of tuberculosis throughout Italy and especially within Rome itself. Trade and military expansion would have acted as vehicles for the further extension of tuberculosis to the provinces via direct transmission from Italian-born Romans to the native populations. However, an alternative explanation may better explain the increase in the number of archeological cases of tuberculosis with the start of the Roman era. A literature review of Roman-era cases and their locations suggests that the development of an urban, Roman way of life resulted in significant increases in prevalence in regions where tuberculosis had previously been endemic only at a low level. PMID:25771202

  2. Application of the Multistate Tuberculosis Pharmacometric Model in Patients With Rifampicin‐Treated Pulmonary Tuberculosis

    PubMed Central

    Simonsson, USH

    2016-01-01

    This is the first clinical implementation of the Multistate Tuberculosis Pharmacometric (MTP) model describing fast‐, slow‐, and nonmultiplying bacterial states of Mycobacterium tuberculosis. Colony forming unit data from 19 patients treated with rifampicin were analyzed. A previously developed rifampicin population pharmacokinetic (PK) model was linked to the MTP model previously developed using in vitro data. Drug effect was implemented as exposure‐response relationships tested at several effect sites, both alone and in combination. All MTP model parameters were fixed to in vitro estimates except Bmax. Drug effect was described by an on/off effect inhibiting growth of fast‐multiplying bacteria in addition to linear increase of the stimulation of the death rate of slow‐ and nonmultiplying bacteria with increasing drug exposure. Clinical trial simulations predicted well three retrospective clinical trials using the final model that confirmed the potential utility of the MTP model in antitubercular drug development. PMID:27299939

  3. Application of the Multistate Tuberculosis Pharmacometric Model in Patients With Rifampicin-Treated Pulmonary Tuberculosis.

    PubMed

    Svensson, R J; Simonsson, Ush

    2016-05-01

    This is the first clinical implementation of the Multistate Tuberculosis Pharmacometric (MTP) model describing fast-, slow-, and nonmultiplying bacterial states of Mycobacterium tuberculosis. Colony forming unit data from 19 patients treated with rifampicin were analyzed. A previously developed rifampicin population pharmacokinetic (PK) model was linked to the MTP model previously developed using in vitro data. Drug effect was implemented as exposure-response relationships tested at several effect sites, both alone and in combination. All MTP model parameters were fixed to in vitro estimates except Bmax . Drug effect was described by an on/off effect inhibiting growth of fast-multiplying bacteria in addition to linear increase of the stimulation of the death rate of slow- and nonmultiplying bacteria with increasing drug exposure. Clinical trial simulations predicted well three retrospective clinical trials using the final model that confirmed the potential utility of the MTP model in antitubercular drug development. PMID:27299939

  4. On the determination of the effective transmission factor for stainless steel ovoid shielding segments and estimation of their shielding efficacy for the clinical situation.

    PubMed

    Verellen, D; De Neve, W; Van den Heuvel, F; Storme, G; Coen, V; Coghe, M

    1994-11-01

    Commercially available ovoid tubes for gynecological applications used in conjunction with the microSelectron-HDR (Nucletron International B.V., Waardegelder 1, 3905 TH Veenendaal, The Netherlands) for 192Ir sources, allow for shielding. Publications concerning the transmission properties of these 4.5-mm thick stainless steel (AISI number 303/304) shielding segments are scarce and not compatible for implementation in treatment planning. Therefore the effect of shielding on dose distribution is unknown. The effective transmission factor has been measured and implemented in the planning computations. Screening efficacy was evaluated on 20 actual treatment plans, analyzing dose reduction to critical tissue and comparing dose distribution in planes relevant for this particular application. Due to high transmission (effective transmission factor = 0.85), stainless steel screening segments only provide low, local dose reductions of maximum 15%. A new approach with regard to optimization and source configuration is needed to reduce dose to vulnerable tissue, exploiting the screening segments to a maximum extent. Better shielding, especially at the midline (plane bisecting the ovoids) could be expected by using shielding segments with other geometrical characteristics. PMID:7891627

  5. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission.

    PubMed

    Kakani, Sravan; LaBeaud, A Desirée; King, Charles H

    2010-11-01

    Rift Valley fever (RVF) virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighbouring regions, RVF is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. Introduction of West Nile virus to North America has shown the potential for "exotic" viral pathogens to become embedded in local ecological systems. While RVF is known to infect and amplify within domestic livestock, such as taurine cattle, sheep and goats, if RVF virus is accidentally or intentionally introduced into North America, an important unknown factor will be the role of local wildlife in the maintenance or propagation of virus transmission. We examined the potential impact of RVF transmission via white-tailed deer (Odocoileus virginianus) in a typical north-eastern United States urban-suburban landscape, where livestock are rare but where these potentially susceptible, ungulate wildlife are highly abundant. Model results, based on overlap of mosquito, human and projected deer densities, indicate that a significant proportion (497/1186 km(2), i.e. 42%) of the urban and peri-urban landscape could be affected by RVF transmission during the late summer months. Deer population losses, either by intervention for herd reduction or by RVF-related mortality, would substantially reduce these likely transmission zones to 53.1 km(2), i.e. by 89%. PMID:21080319

  6. [Tuberculosis in Europe and Poland--new molecular families and new resistance patterns].

    PubMed

    Augustynowicz-Kopeć, Ewa; Zwolska, Zofia

    2008-01-01

    At present despite methods of fast recognition of the disease and efficient antituberculosis drugs not only we cannot contain the epidemic but we can see an increase in new cases of tuberculosis including its drug resistant variety. Causes of aggravation of the situation are varied and ought to be examined separately in case of any particular region. One of the major ones are bad programmes of fighting against the disease or their inadequate realization, ignoring a problem of tuberculosis in developed countries, lack of money for treatment in developing countries and coincidence with HIV virus. Among the mentioned factors the phenomenon of drug resistance is considered one of most important reasons of expansion of tuberculosis in the modern world. In epidemiological investigations it is important to determine, apart from drug resistance patterns, what molecular families strains belong to. This allows us to track their transmission routes. Genotyping has given us knowledge of the threats connected with transmission of the infection and made it possible to identify a risk factor which is the cause of MDR (multidrug-resistant), XDR (extensively drug-resistant tuberculosis) strains dissemination as well as strains representing new molecular families. Results of some analyses proved to be surprising. For instance high proportion of genetically similar strains has been shown in countries of low incidence. It proves higher than expected transmission in societies of high economic standard. Analyses of DNA of mycobacteria led to distinguishing several genetic families among which M. tuberculosis Beijing is one of most important. PMID:18536233

  7. Potential of Rapid Diagnosis for Controlling Drug-Susceptible and Drug-Resistant Tuberculosis in Communities Where Mycobacterium tuberculosis Infections Are Highly Prevalent ▿

    PubMed Central

    Uys, Pieter W.; Warren, Robin; van Helden, Paul D.; Murray, Megan; Victor, Thomas C.

    2009-01-01

    The long-term persistence of Mycobacterium tuberculosis in communities with high tuberculosis prevalence is a serious problem aggravated by the presence of drug-resistant tuberculosis strains. Drug resistance in an individual patient is often discovered only after a long delay, particularly if the diagnosis is based on current culture-based drug sensitivity testing methods. During such delays, the patient may transmit tuberculosis to his or her contacts. Rapid diagnosis of drug resistance would be expected to reduce this transmission and hence to decrease the prevalence of drug-resistant strains. To investigate this quantitatively, a mathematical model was constructed, assuming a homogeneous population structure typical of communities in South Africa where tuberculosis incidence is high. Computer simulations performed with this model showed that current control strategies will not halt the spread of multidrug-resistant tuberculosis in such communities. The simulations showed that the rapid diagnosis of drug resistance can be expected to reduce the incidence of drug-resistant cases provided the additional measure of screening within the community is implemented. PMID:19297604

  8. Potential of rapid diagnosis for controlling drug-susceptible and drug-resistant tuberculosis in communities where Mycobacterium tuberculosis infections are highly prevalent.

    PubMed

    Uys, Pieter W; Warren, Robin; van Helden, Paul D; Murray, Megan; Victor, Thomas C

    2009-05-01

    The long-term persistence of Mycobacterium tuberculosis in communities with high tuberculosis prevalence is a serious problem aggravated by the presence of drug-resistant tuberculosis strains. Drug resistance in an individual patient is often discovered only after a long delay, particularly if the diagnosis is based on current culture-based drug sensitivity testing methods. During such delays, the patient may transmit tuberculosis to his or her contacts. Rapid diagnosis of drug resistance would be expected to reduce this transmission and hence to decrease the prevalence of drug-resistant strains. To investigate this quantitatively, a mathematical model was constructed, assuming a homogeneous population structure typical of communities in South Africa where tuberculosis incidence is high. Computer simulations performed with this model showed that current control strategies will not halt the spread of multidrug-resistant tuberculosis in such communities. The simulations showed that the rapid diagnosis of drug resistance can be expected to reduce the incidence of drug-resistant cases provided the additional measure of screening within the community is implemented. PMID:19297604

  9. [Tuberculosis in Asia].

    PubMed

    2002-10-01

    1. Philippines: The development, expansion and maintenance of pilot area activities: Cristina B. Giango (Technical Division, Cebu Provincial Health Office, the Philippines) In 1994, the Department of Health developed the new NTP policies based on WHO recommendations and started a pilot project in Cebu Province in collaboration with the Japan International Cooperation Agency. To test its feasibility and effectiveness, the new NTP policies were pre-tested in one city and one Rural Health Unit. The test showed a high rate of three sputum collection (90%), high positive rate (10%), and high cure rate (80%). Before the new guidelines were introduced, the new policy was briefed, a baseline survey of the facility was conducted, equipment was provided, and intensive training was given. Recording/Reporting forms and procedures were also developed to ensure accurate reporting. Supervision, an important activity to ensure effective performance, was institutionalized. Laboratory services were strengthened, and a quality-control system was introduced in 1995 to ensure the quality of the laboratory services. With the implementation of DOTS strategy, barangay health workers were trained as treatment partners. In partnership with the private sector, the TB Diagnostic Committee was organized to deliberate and assess sputum negative but X-ray positive cases. The implementation of the new NTP guidelines in Cebe Province has reached a satisfactory level, the cure rate and positive rate have increased, and laboratory services have improved. Because of its successful implementation, the new NTP guidelines are now being used nationwide. 2. Nepal: The DOTS Strategy in the area with hard geographic situation: Dirgh Singh Bam (National Tuberculosis Center, Nepal) Three groups of factors characterize the population of Nepal: 1) Socio-cultural factors, e.g. migration, poverty, language; 2) Environmental factors, e.g. geography and climate; and 3) Political factors, prisoners and refugee

  10. Tuberculosis associates with both airflow obstruction and low lung function: BOLD results

    PubMed Central

    Amaral, André F. S.; Coton, Sonia; Kato, Bernet; Tan, Wan C.; Studnicka, Michael; Janson, Christer; Gislason, Thorarinn; Mannino, David; Bateman, Eric D.; Buist, Sonia; Burney, Peter G. J.

    2015-01-01

    Background In small studies and cases series, a history of tuberculosis has been associated with both airflow obstruction, which is characteristic of chronic obstructive pulmonary disease, and restrictive patterns on spirometry. Objective To assess the association between a history of tuberculosis and airflow obstruction and spirometric abnormalities in adults. Methods The study was performed in adults, aged 40 and above, who took part in the multicentre cross-sectional, general population-based, Burden of Obstructive Lung Disease study, had provided acceptable post-bronchodilator spirometry measurements and information on a history of tuberculosis. The associations between a history of tuberculosis and airflow obstruction and spirometric restriction were assessed within each participating centre, and estimates combined using meta-analysis. These estimates were stratified by high and low/middle income countries, according to gross national income. Results A self-reported history of tuberculosis was associated with airflow obstruction (adjusted odds ratio = 2.51, 95% confidence interval 1.83-3.42) and spirometric restriction (adjusted odds ratio = 2.13, 95% confidence interval 1.42-3.19). Conclusion A history of tuberculosis was associated with both airflow obstruction and spirometric restriction, and should be considered as a potentially important cause of obstructive disease and low lung function, particularly where tuberculosis is common. PMID:26113680

  11. Fish mycobacteriosis (Tuberculosis)

    USGS Publications Warehouse

    Parisot, T.J.; Wood, J.W.

    1959-01-01

    The etiologic agent for the bacterial disease, "fish tuberculosis" (more correctly "mycobacteriosis"), was first observed in carp in 189& from a pond in France. Subsequently similar agents have been isolated from or observed in fish in fresh water, salt water, and brackish water, in fish in aquaria, hatcheries, and natural habitat~ (wild populations of fish). The disease has been recognized as an important infection among hatchery reared salmonid fishes on the West Coast of the United States, and in aquarium fishes such as the neon tetra, the Siamese fighting fish, and in salt water fish held in zoological displays.

  12. Tuberculosis in the AIDS era.

    PubMed Central

    Sepkowitz, K A; Raffalli, J; Riley, L; Kiehn, T E; Armstrong, D

    1995-01-01

    A resurgence of tuberculosis has occurred in recent years in the United States and abroad. Deteriorating public health services, increasing numbers of immigrants from countries of endemicity, and coinfection with the human immunodeficiency virus (HIV) have contributed to the rise in the number of cases diagnosed in the United States. Outbreaks of resistant tuberculosis, which responds poorly to therapy, have occurred in hospitals and other settings, affecting patients and health care workers. This review covers the pathogenesis, epidemiology, clinical presentation, laboratory diagnosis, and treatment of Mycobacterium tuberculosis infection and disease. In addition, public health and hospital infection control strategies are detailed. Newer approaches to epidemiologic investigation, including use of restriction fragment length polymorphism analysis, are discussed. Detailed consideration of the interaction between HIV infection and tuberculosis is given. We also review the latest techniques in laboratory evaluation, including the radiometric culture system, DNA probes, and PCR. Current recommendations for therapy of tuberculosis, including multidrug-resistant tuberculosis, are given. Finally, the special problem of prophylaxis of persons exposed to multidrug-resistant tuberculosis is considered. PMID:7621399

  13. [Occupational exposure to Mycobacterium tuberculosis complex: state of the art and prospects].

    PubMed

    Verso, M G; Caracappa, S; Vitale, F; Vesco, G; Picciotto, D

    2002-01-01

    Tuberculosis, disease never wiped out in the world, is still actual for many reasons, such as imposing emigration from poor to industrialized countries, spreading of Mycobacteria drug-resistant and presence of AIDS sick subjects. Estimation of world cases seems to under-value real number; moreover physicians consider as etiological agent only Mycobacterium tuberculosis, disregarding others Mycobacteria, such as M. bovis, giving rise a disease similar to that caused by M. tuberculosis. To single out all these variants, it's necessary to use very specific and sensitive diagnostic methods, such as Polymerase Chain Reaction, evaluating also possible work exposure, especially when occurs contacts with infectious animals. PMID:12161953

  14. Evaluation of disease patterns, treatment and prognosis of tuberculosis in AIDS patient.

    PubMed

    Atomiya, Angela Naomi; Uip, David Emerson; Leite, Olavo Henrique Munhoz

    2002-02-01

    Patterns of disease, diagnosis, treatment and prognosis of tuberculosis in 100 patients co-infected with AIDS at Casa da AIDS clinic was studied. Demographic characteristics were as follows: 76 male patients, 24 female patients, 67 caucasian, average 35.8 years-old (SD +/- 8.5). Sexual transmission of HIV was reported in 68 patients. Pulmonary tuberculosis was seen in 40 patients, extrapulmonary in 11, and combined in 49 patients. In 63 patients, TCD(4)(+) counts were below 200/mm(3) when tuberculosis was diagnosed. Fifty-five patients had their diagnoses confirmed by bacteriological identification of Mycobacterium; either through direct observation and/or culture. Tuberculosis was treated with rifampin, isoniazid and pyrazinamide in 60 patients, reinforced treatment in 14 and alternative treatment in the other 13 patients. Tuberculosis therapy lasted up to 9 months in 66% of the patients. Fifty-four patients were treated with a two-drug antiretroviral regimen and the remaining 46 patients received a triple regimen, which included a protease inhibitor. Among the latter, 35 patients were co-treated with rifampin. The occurrence of hepatic liver enzyme abnormalities was statistically related to alternative antiretroviral regimens (p = 0.01) and to the co-administration of rifampin and protease inhibitor (p = 0.019). Clinical resolution of tuberculosis was obtained in 74 patients. Twelve patients died during tuberculosis treatment. Resolution of tuberculosis was statistically significant related to antituberculosis treatment adherence (p = 0.001). The risk of no response to the treatment was 1.84 times more frequent among patients treated with alternative regimens regardless of the duration of the therapy. We conclude that the characteristics of tuberculosis in HIV infected patients requires that special attention be directed to the types and duration of both antiretroviral and anti-TB therapy in order to achieve the highest level of care. PMID:11980601

  15. Tuberculosis among homeless population from Medellín, Colombia: associated mental disorders and socio-demographic characteristics.

    PubMed

    Hernández Sarmiento, José Mauricio; Correa, Nidia; Correa, Marta; Franco, José Gabriel; Alvarez, Matilde; Ramírez, Clara; Gómez, Lina M; Toro, Antonio Carlos; Londoño, Nora Helena; Martínez, Milton; Restrepo, Mary Alejandra; Zapata, Elsa; Mejía, Gloria Isabel; Robledo, Jaime

    2013-08-01

    Homeless people are highly susceptible to tuberculosis. It has been suggested that this population have high rates of mental disorders associated with tuberculosis. We assessed tuberculosis incidence, its transmission patterns and association with socio-demographic factors and mental disorders in Colombian homeless people. Prospective study which socio-demographic characteristics and mental disorders were assessed through interviews. Sputa from patients with respiratory symptoms were processed and clinical isolates analyzed by IS6110-RFLP. Multivariate analysis performed by logistic regression model. From 426 homeless studied, tuberculosis incidence found was 7.9 %. 44 % of isolates were clustering. It was found high risk of having tuberculosis associated with income from drugs trade (OR: 3.40 [95 % CI: 1.28-9.05]), dysthymia (OR: 2.54 [95 % CI: 1.10-5.86]) and receiving food from other homeless (OR: 2.47 [95 % CI: 1.16-5.25]). Tuberculosis incidence and degree of transmission are high in homeless studied. Implementing programs to better control tuberculosis among homeless population must consider socio-demographic factors and mental disorders associated with the disease. PMID:23340806

  16. Redox biology of tuberculosis pathogenesis.

    PubMed

    Trivedi, Abhishek; Singh, Nisha; Bhat, Shabir Ahmed; Gupta, Pawan; Kumar, Ashwani

    2012-01-01

    Mycobacterium tuberculosis (Mtb) is one of the most successful human pathogens. Mtb is persistently exposed to numerous oxidoreductive stresses during its pathogenic cycle of infection and transmission. The distinctive ability of Mtb, not only to survive the redox stress manifested by the host but also to use it for synchronizing the metabolic pathways and expression of virulence factors, is central to its success as a pathogen. This review describes the paradigmatic redox and hypoxia sensors employed by Mtb to continuously monitor variations in the intracellular redox state and the surrounding microenvironment. Two component proteins, namely, DosS and DosT, are employed by Mtb to sense changes in oxygen, nitric oxide, and carbon monoxide levels, while WhiB3 and anti-sigma factor RsrA are used to monitor changes in intracellular redox state. Using these and other unidentified redox sensors, Mtb orchestrates its metabolic pathways to survive in nutrient-deficient, acidic, oxidative, nitrosative, and hypoxic environments inside granulomas or infectious lesions. A number of these metabolic pathways are unique to mycobacteria and thus represent potential drug targets. In addition, Mtb employs versatile machinery of the mycothiol and thioredoxin systems to ensure a reductive intracellular environment for optimal functioning of its proteins even upon exposure to oxidative stress. Mtb also utilizes a battery of protective enzymes, such as superoxide dismutase (SOD), catalase (KatG), alkyl hydroperoxidase (AhpC), and peroxiredoxins, to neutralize the redox stress generated by the host immune system. This chapter reviews the current understanding of mechanisms employed by Mtb to sense and neutralize redox stress and their importance in TB pathogenesis and drug development. PMID:22633061

  17. Respiratory infections: pulmonary tuberculosis.

    PubMed

    Choby, Beth A; Hunter, Paul

    2015-02-01

    Family physicians can prevent mortality and disability due to pulmonary tuberculosis (TB) by identifying high-risk patients. Recognition of symptoms (eg, cough for 3 weeks or longer) helps prevent overlooked diagnoses because results of tuberculin skin tests and interferon-gamma release assays are negative in up to 25% and 21%, respectively, of severe acute cases. The typical x-ray findings of cavities, infiltrates, and lymphadenopathy are minimal among immunosuppressed patients. Cases of active TB must be reported to local or state health departments within 24 hours of diagnosis. Sputum acid-fast bacillus tests provide results within hours and help quantify bacterial load but are not highly sensitive, and infection with nontuberculous mycobacteria can cause positive test results. Sputum cultures are adequately sensitive, identify mycobacterial species, and provide organisms for antibiotic susceptibility testing but require weeks for results. Molecular detection of Mycobacterium tuberculosis and of antibiotic-resistant mutations can expedite diagnosis and management of drug-resistant TB. Management of active TB should include directly observed therapy. Standard 6-month therapy with rifampin, isoniazid, pyrazinamide, and ethambutol resolves infection in nearly all immunocompetent adults with pansensitive TB. Multidrug-resistant TB requires second-line antibiotics (eg, fluoroquinolones, linezolid) in individualized regimens lasting 2 years. Management of latent TB infection prevents progression to active TB disease, particularly if management is completed within 2 years of infection. PMID:25685923

  18. Immunometabolism in Tuberculosis

    PubMed Central

    Shi, Lanbo; Eugenin, Eliseo A.; Subbian, Selvakumar

    2016-01-01

    Immunometabolism, the study of the relationship between bioenergetic pathways and specific functions of immune cells, has recently gained increasing appreciation. In response to infection, activation of the host innate and adaptive immune cells is accompanied by a switch in the bioenergetic pathway from oxidative phosphorylation to glycolysis, a metabolic remodeling known as the Warburg effect, which is required for the production of antimicrobial and pro-inflammatory effector molecules. In this review, we summarize the current understanding of the Warburg effect and discuss its association with the expression of host immune responses in tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb). We also discuss potential mechanisms underlying the Warburg effect with a focus on the expression and regulation of hypoxia-inducible factor 1 alpha (HIF-1α), the regulatory subunit of HIF-1, a major transcription regulator involved in cellular stress adaptation processes, including energy metabolism and antimicrobial responses. We also propose a novel hypothesis that Mtb perturbs the Warburg effect of immune cells to facilitate its survival and persistence in the host. A better understanding of the dynamics of metabolic states of immune cells and their specific functions during TB pathogenesis can lead to the development of immunotherapies capable of promoting Mtb clearance and reducing Mtb persistence and the emergence of drug resistant strains. PMID:27148269

  19. Immunometabolism in Tuberculosis.

    PubMed

    Shi, Lanbo; Eugenin, Eliseo A; Subbian, Selvakumar

    2016-01-01

    Immunometabolism, the study of the relationship between bioenergetic pathways and specific functions of immune cells, has recently gained increasing appreciation. In response to infection, activation of the host innate and adaptive immune cells is accompanied by a switch in the bioenergetic pathway from oxidative phosphorylation to glycolysis, a metabolic remodeling known as the Warburg effect, which is required for the production of antimicrobial and pro-inflammatory effector molecules. In this review, we summarize the current understanding of the Warburg effect and discuss its association with the expression of host immune responses in tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb). We also discuss potential mechanisms underlying the Warburg effect with a focus on the expression and regulation of hypoxia-inducible factor 1 alpha (HIF-1α), the regulatory subunit of HIF-1, a major transcription regulator involved in cellular stress adaptation processes, including energy metabolism and antimicrobial responses. We also propose a novel hypothesis that Mtb perturbs the Warburg effect of immune cells to facilitate its survival and persistence in the host. A better understanding of the dynamics of metabolic states of immune cells and their specific functions during TB pathogenesis can lead to the development of immunotherapies capable of promoting Mtb clearance and reducing Mtb persistence and the emergence of drug resistant strains. PMID:27148269

  20. Transmission eigenvalues

    NASA Astrophysics Data System (ADS)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  1. Making a timely diagnosis of pulmonary tuberculosis

    PubMed Central

    Long, Richard

    2015-01-01

    Making a timely diagnosis of adult-type pulmonary tuberculosis (TB) is critical to interrupting transmission and optimizing treatment outcomes. A hypothesis based on clinical experience is that a timely diagnosis may be made by addressing seven clinical rubrics: six related to history, one to the laboratory. Responses may be considered to be part of a clinical heuristic for making a timely diagnosis of pulmonary TB. The larger the number of affirmative responses, the more likely the diagnosis, although it is probable some questions carry more weight than others. The radiograph is key and may almost be considered to be confirmatory of the history. Collectively, the responses should prompt suspicion of pulmonary TB – submission of sputum for acid-fast bacilli smear and culture, and respiratory isolation. PMID:26469154

  2. Transmission eigenvalues

    NASA Astrophysics Data System (ADS)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  3. Tuberculosis care: an evaluability study

    PubMed Central

    Coelho, Ardigleusa Alves; Martiniano, Cláudia Santos; Brito, Ewerton Willian Gomes; Negrão, Oswaldo Gomes Corrêa; Arcêncio, Ricardo Alexandre; Uchôa, Severina Alice da Costa

    2014-01-01

    OBJECTIVE: to verify whether the tuberculosis control program (TCP) is evaluable and to examine the feasibility of building an evaluation model in apriority municipality for the control of tuberculosis. METHOD: this evaluability study was conducted in a municipality in northeastern Brazil. For data collection, documental analysis and interviews with key informants were performed. For indicator validation, the nominal group technique was adopted. RESULTS: the details of TCP were described, and both the logical model and the classification framework for indicators were developed and agreed up on, with the goal of characterizing the structural elements of the program, defining the structure and process indicators, and formulating the evaluation questions. CONCLUSION: TCP is evaluable. Based on logical operational analysis, it was possible to evaluate the adequacy of the program goals for the control of tuberculosis. Therefore, the performance of a summative evaluation is recommended, with a focus on the analysis of the effects of tuberculosis control interventions on decreasing morbidity and mortality. PMID:25493675

  4. Tuberculosis treatment and drug regimens.

    PubMed

    Sotgiu, Giovanni; Centis, Rosella; D'ambrosio, Lia; Migliori, Giovanni Battista

    2015-05-01

    Tuberculosis is an airborne infectious disease treated with combination therapeutic regimens. Adherence to long-term antituberculosis therapy is crucial for maintaining adequate blood drug level. The emergence and spread of drug-resistant Mycobacterium tuberculosis strains are mainly favored by the inadequate medical management of the patients. The therapeutic approach for drug-resistant tuberculosis is cumbersome, because of the poor, expensive, less-effective, and toxic alternatives to the first-line drugs. New antituberculosis drugs (bedaquiline and delamanid) have been recently approved by the health authorities, but they cannot represent the definitive solution to the clinical management of drug-resistant tuberculosis forms, particularly in intermediate economy settings where the prevalence of drug resistance is high (China, India, and former Soviet Union countries). New research and development activities are urgently needed. Public health policies are required to preserve the new and old therapeutic options. PMID:25573773

  5. IS6110 fingerprinting of drug-resistant Mycobacterium tuberculosis strains isolated in Germany during 1995.

    PubMed Central

    Niemann, S; Rüsch-Gerdes, S; Richter, E

    1997-01-01

    The epidemiological relatedness of drug-resistant Mycobacterium tuberculosis strains isolated in Germany in 1995 was evaluated by the standardized IS6110 fingerprinting method. Altogether, 196 M. tuberculosis isolates from 167 patients were analyzed. A large degree of IS6110 polymorphism was found, ranging from 1 to 20 copies. Multiple isolates from one patient generally remained stable over a period of up to 1 year. However, one strain showed an additional fragment 7 months after the first isolate was obtained. Isolates from 55 patients (33%) showed identical fingerprint patterns or fingerprint patterns that differed only in one band, and thus they were clustered in 22 fingerprint groups. Specific transmission links could be established between members of four groups, e.g., transmission by family contacts. In one case, transmission of a multidrug-resistant strain to a patient initially infected with a drug-susceptible strain could be shown. Besides these fingerprint groups, 30 of the 167 isolates (approximately 18%) could be grouped in two fingerprint clusters with a similarity of at least 78%. Approximately 60% of the patients of these two clusters were known to be immigrants from the former Soviet Union, and one patient is still living in Belarus. In conclusion, our results indicate that (i) transmission of drug-resistant strains contributes substantially to the emergence of drug-resistant tuberculosis in Germany and (ii) drug-resistant M. tuberculosis strains were presumably carried over from the former Soviet Union to Germany by immigrants. PMID:9399486

  6. Intrafamilial cluster of pulmonary tuberculosis due to Mycobacterium bovis of the African 1 clonal complex.

    PubMed

    Godreuil, S; Jeziorski, E; Bañuls, A L; Fraisse, T; Van de Perre, P; Boschiroli, M L

    2010-12-01

    A new clonal complex of Mycobacterium bovis present at high frequency in cattle from west central African countries has been described as the African 1 (Af1) clonal complex. Here, the first intrafamilial cluster of human tuberculosis cases due to M. bovis Af1 clonal complex strains is reported. We discuss hypotheses regarding modes of transmission. PMID:20980573

  7. Tuberculosis origin: The Neolithic scenario.

    PubMed

    Hershkovitz, Israel; Donoghue, Helen D; Minnikin, David E; May, Hila; Lee, Oona Y-C; Feldman, Michal; Galili, Ehud; Spigelman, Mark; Rothschild, Bruce M; Bar-Gal, Gila Kahila

    2015-06-01

    This paper follows the dramatic changes in scientific research during the last 20 years regarding the relationship between the Mycobacterium tuberculosis complex and its hosts - bovids and/or humans. Once the M. tuberculosis and Mycobacterium bovis genomes were sequenced, it became obvious that the old story of M. bovis evolving into the human pathogen should be reversed, as M. tuberculosis is more ancestral than M. bovis. Nevertheless, the timescale and geographical origin remained an enigma. In the current study human and cattle bone samples were examined for evidence of tuberculosis from the site of Atlit-Yam in the Eastern Mediterranean, dating from 9250 to 8160 (calibrated) years ago. Strict precautions were used to prevent contamination in the DNA analysis, and independent centers used to confirm authenticity of findings. DNA from five M. tuberculosis genetic loci was detected and had characteristics consistent with extant genetic lineages. High performance liquid chromatography was used as an independent method of verification and it directly detected mycolic acid lipid biomarkers, specific for the M. tuberculosis complex. These, together with pathological changes detected in some of the bones, confirm the presence of the disease in the Levantine populations during the Pre-pottery Neolithic C period, more than 8000 years ago. PMID:25726364

  8. Leveling of Tuberculosis Incidence - United States, 2013-2015.

    PubMed

    Salinas, Jorge L; Mindra, Godwin; Haddad, Maryam B; Pratt, Robert; Price, Sandy F; Langer, Adam J

    2016-01-01

    After 2 decades of progress toward tuberculosis (TB) elimination with annual decreases of ≥0.2 cases per 100,000 persons (1), TB incidence in the United States remained approximately 3.0 cases per 100,000 persons during 2013-2015. Preliminary data reported to the National Tuberculosis Surveillance System indicate that TB incidence among foreign-born persons in the United States (15.1 cases per 100,000) has remained approximately 13 times the incidence among U.S.-born persons (1.2 cases per 100,000). Resuming progress toward TB elimination in the United States will require intensification of efforts both in the United States and globally, including increasing U.S. efforts to detect and treat latent TB infection, strengthening systems to interrupt TB transmission in the United States and globally, accelerating reductions in TB globally, particularly in the countries of origin for most U.S. PMID:27010173

  9. Molecular epidemiology of tuberculosis: achievements and challenges to current knowledge.

    PubMed Central

    Murray, Megan; Nardell, Edward

    2002-01-01

    Over the past 10 years, molecular methods have become available with which to strain-type Mycobacterium tuberculosis. They have allowed researchers to study certain important but previously unresolved issues in the epidemiology of tuberculosis (TB). For example, some unsuspected microepidemics have been revealed and it has been shown that the relative contribution of recently acquired disease to the TB burden in many settings is far greater than had been thought. These findings have led to the strengthening of TB control. Other research has demonstrated the existence and described the frequency of exogenous reinfection in areas of high incidence. Much recent work has focused on the phenotypic variation among strains and has evaluated the relative transmissibility, virulence, and immunogenicity of different lineages of the organism. We summarize the recent achievements in TB epidemiology associated with the introduction of DNA fingerprinting techniques, and consider the implications of this technology for the design and analysis of epidemiological studies. PMID:12132006

  10. Mycobacterium tuberculosis virulence: insights and impact on vaccine development.

    PubMed

    Delogu, Giovanni; Provvedi, Roberta; Sali, Michela; Manganelli, Riccardo

    2015-01-01

    The existing TB vaccine, the attenuated Mycobacterium bovis strain BCG, is effective in protecting infants from severe forms of the disease, while its efficacy in protecting adults from pulmonary TB is poor. In the last two decades, a renewed interest in TB resulted in the development of several candidate vaccines that are now entering clinical trials. However, most of these vaccines are based on a common rationale and aim to induce a strong T-cell response against Mycobacterium tuberculosis. Recent advancements in the understanding of M. tuberculosis virulence determinants and associated pathogenic strategies are opening a new and broader view of the complex interaction between this remarkable pathogen and the human host, providing insights at molecular level that could lead to a new rationale for the design of novel antitubercular vaccines. A vaccination strategy that simultaneously targets different steps in TB pathogenesis may result in improved protection and reduced TB transmission. PMID:26119086

  11. Disinfecting endoscopes: how not to transmit Mycobacterium tuberculosis by bronchoscopy.

    PubMed Central

    Leers, W D

    1980-01-01

    Mycobacterium tuberculosis was cultured from the bronchial washings of two patients who underwent bronchoscopy consecutively with the same bronchoscope. Active pulmonary tuberculosis was later confirmed in the first patient, whereas the second patient had clinical and serologic evidence of infection with respiratory syncytial virus. The bronchoscope had been cleaned with an iodophor disinfectant, which had not destroyed the tubercle bacilli. The agent recommended for chemical disinfection of fibreoptic bronchoscopes is 2% glutaraldehyde solution; the instrument should be immersed in it for 10 to 30 minutes. Five hours' exposure to ethylene oxide is recommended for sterilization of instruments. These procedures must be preceded by adequate mechanical cleaning. Then transmission of pathogenic organisms during endoscopy, which can result in nosocomial disease, misdiagnosis or inappropriate treatment, will be avoided. Images FIG. 1 FIG. 2 FIG. 3 PMID:6790150

  12. HIV-associated tuberculosis in developing countries: clinical features, diagnosis, and treatment.

    PubMed Central

    Raviglione, M. C.; Narain, J. P.; Kochi, A.

    1992-01-01

    This article reviews the clinical aspects and diagnosis of HIV-associated tuberculosis in developing countries, and summarizes WHO's recommendations for treatment. According to WHO estimates (early 1992) over 4 million persons worldwide have been infected with HIV and tuberculosis; 95% of them are in the developing countries. Clinical features of HIV-associated pulmonary tuberculosis in adults are frequently atypical, particularly in the late stage of HIV infection, with non-cavitary disease, lower lobe infiltrates, hilar lymphadenopathy and pleural effusion. More typical post-primary tuberculosis with upper lobe infiltrates and cavitations is seen in the earlier stages of HIV infection. Extrapulmonary tuberculosis is reported more frequently, despite the difficulties in diagnosing it. WHO's recent guidelines recommend 6-month short-course chemotherapy with isoniazid, rifampicin, pyrazinamide and ethambutol for patients with HIV-associated tuberculosis. The older 12-month regimen without rifampicin is much less effective. Streptomycin should not be used, because of the risk of transmitting blood-borne pathogens through contaminated needles. Thioacetazone should be abandoned, because of severe adverse reactions observed among HIV-infected patients. The roles of preventive chemotherapy and BCG vaccination for prevention of tuberculosis are also briefly discussed. PMID:1394786

  13. [The epidemiology of tuberculosis and of the resistance to antitubercular agents].

    PubMed

    Aït Khaled, N; Enarson, D; Billo, N

    1997-12-01

    Tuberculosis is once more a subject of world wide preoccupation; since 1985 a disturbing recrudescence of this disease has been noted in numerous countries related to population growth and the worsening of poverty in those countries without natural resources, and disadvantaged groups living on the margins of society in rich countries, along with the occurrence of an epidemic of HIV (VIH). In numerous developed countries where tuberculosis no longer represents a public health problem, the care services have little by little been closed or re-orientated and the principles of treatment of tuberculosis have been forgotten. The direct consequence of this has often been inadequate treatment and its corollary: the emergence of strains multiresistant to Isoniazid and Rifampicin. If the current epidemiological tendencies are confirmed and no supplementary action is taken, the WHO (OMS) has estimated that during the ten years between 1990 and the millennium there will be 88 million new cases of tuberculosis and 30 million people will die of tuberculosis. However the tendencies can be reversed and tuberculosis could still be eliminated. The struggle against tuberculosis is a world wide emergency and the hope of controlling the situation before an increase in multiresistant strains which would render the trend irreversible, rests on a general application of correct and coherent national programmes. Such a programme as the UICTMR model had already been carried out as has the proof of their efficacy. PMID:9496587

  14. Mutations Prevalent among Rifampin- and Isoniazid-Resistant Mycobacterium tuberculosis Isolates from a Hospital in Vietnam

    PubMed Central

    Caws, M.; Duy, Phan Minh; Tho, Dau Quang; Lan, Nguyen Thi Ngoc; Hoa, Dai Viet; Farrar, Jeremy

    2006-01-01

    Vietnam is ranked 13th among the WHO list of 22 high-burden countries, based upon estimated total number of tuberculosis cases. Despite having a model national tuberculosis program, consistently achieving and exceeding WHO targets for detection and cure, drug-resistant and multidrug-resistant tuberculosis cases continue to rise. Rapid multidrug-resistant tests applicable in this setting, coupled with effective treatment regimens, would be a useful tool in reversing this trend, allowing early identification of patients with multidrug-resistant tuberculosis and avoiding resistance-amplifying regimens. Sequencing of consecutive isolates identified by the National Tuberculosis Program showed 89% of isoniazid-resistant isolates could be detected by targeting just 2 codons, katG 315 and −15C→T in the inhA promoter, while rifampin resistance will be more complex to detect, with many different mutation and insertion events in rpoB. The most prevalent rifampin resistance-conferring mutations, as in other countries, were in rpoB codons 531 (43%), 526 (31%), and 516 (15%). However, a hybridization-based resistance test with probes targeting the 5 most common mutations would only detect 78% of rifampin-resistant isolates. Overall, these data suggest that rifampin resistance may be used as a surrogate marker for multidrug-resistant tuberculosis and that a sensitivity of between 70 to 80% may be possible for rapid molecular detection of multidrug-resistant tuberculosis in this setting. PMID:16825345

  15. Prevalence and risk factors for infection of bovine tuberculosis in indigenous cattle in the Serengeti ecosystem, Tanzania

    PubMed Central

    2013-01-01

    Background Bovine tuberculosis (bTB) is a chronic debilitating disease and is a cause of morbidity and mortality in livestock, wildlife and humans. This study estimated the prevalence and risk factors associated with bovine tuberculosis transmission in indigenous cattle at the human-animal interface in the Serengeti ecosystem of Tanzania. Results A total of 1,103 indigenous cattle from 32 herds were investigated for the presence of bTB using the Single Intradermal Comparative Tuberculin Test. Epidemiological data on herd structure, management and grazing system were also collected. The apparent individual animal prevalence of tuberculin reactors was 2.4% (95% confidence interval (CI), 1.7 – 3.5%), whereas the true prevalence was 0.6% CI, 0.6 – 0.7% as indicated by a reaction to avian tuberculin purified protein derivatives (PPD) which is more than 4 mm greater than the reaction to avian tuberculin PPD. The results showed that 10.6% (117/1,103) showed non-specific reactions (atypical mycobacterium). The herd prevalence of 50% (16/32) was found. Tuberculin skin test results were found to be significantly associated with age, location, size of the household and animal tested. Of 108 respondents, 70 (64.8%) individuals had not heard about bovine tuberculosis at all. Thirty five percent (38/108) of respondents at least were aware of bTB. About 60% (23/38) of respondents who were aware of bTB had some knowledge on how bTB is spread. Eighty one percent (87/108) of respondents were not aware of the presence of bTB in wildlife. There is regular contact between cattle and wild animals due to sharing of grazing land and water sources, with 99% (107/108) of households grazing cattle in communal pastures. Conclusion The study has demonstrated a high reported interaction of livestock with wildlife and poor knowledge of most cattle owners concerning bTB and its transmission pathways among people, livestock and wildlife. Although the overall proportion of animals with bTB is

  16. Counting children with tuberculosis: why numbers matter.

    PubMed

    Seddon, J A; Jenkins, H E; Liu, L; Cohen, T; Black, R E; Vos, T; Becerra, M C; Graham, S M; Sismanidis, C; Dodd, P J

    2015-12-01

    In the last 5 years, childhood tuberculosis (TB) has received increasing attention from international organisations, national TB programmes and academics. For the first time, a number of different groups are developing techniques to estimate the burden of childhood TB. We review the challenges in diagnosing TB in children and the reasons why cases in children can go unreported. We discuss the importance of an accurate understanding of burden for identifying problems in programme delivery, targeting interventions, monitoring trends, setting targets, allocating resources appropriately and providing strong advocacy. We briefly review the estimates produced by new analytical methods, and outline the reasons for recent improvements in our understanding and potential future directions. We conclude that while innovation, collaboration and better data have improved our understanding of the childhood TB burden, it remains substantially incomplete. PMID:26564535

  17. Molecular diagnostics for tuberculosis.

    PubMed

    Noor, K M; Shephard, L; Bastian, I

    2015-04-01

    The phenotypic methods of smear microscopy, culture and indirect drug susceptibility testing (DST) remain the 'gold standard' diagnostics for tuberculosis (TB) in 2015. However, this review demonstrates that genotypic methods are in the ascendancy. Current-generation nucleic acid amplification tests (NAATs) are important supplementary tests for the rapid direct detection of (multidrug-resistant) TB in specific clinical settings. Genotypic detection is already the preferred method of detecting rifampicin and pyrazinamide resistance. Next-generation NAATs able to detect about 10 colony forming units/mL of sputum could replace culture as the initial test for detecting TB. Whole genome sequencing could also plausibly replace phenotypic DST but much work is required in method standardisation, database development and elucidation of all resistance gene determinants. The challenge then will be to rollout these increasingly complex and expensive diagnostics in the low-income countries where TB is prevalent. PMID:25719854

  18. Tuberculosis Drug Development

    PubMed Central

    Getahun, Haileyesus; Chamie, Gabriel; Lienhardt, Christian; Havlir, Diane V.

    2011-01-01

    An unprecedented number of new tuberculosis (TB) medications are currently in development, and there will be great pressure to deploy these new drugs among all populations after their efficacy is demonstrated. People living with HIV experience a large burden of TB and have a particularly pressing need for TB treatments that are shorter and less toxic. In addition, all people living with HIV now require antiretroviral therapy during TB treatment. A roadmap of the research, programmatic, and regulatory considerations includes the following: (1) inclusion of people living with HIV early in clinical trials for treatment and prevention using new TB medications, (2) prioritization of key studies of HIV–TB drug interactions and interactions between new TB agents, and (3) optimization of clinical trial infrastructure, laboratory capacity, and drug susceptibility testing. PMID:21868507

  19. Bioinformatics Identification of Drug Resistance-Associated Gene Pairs in Mycobacterium tuberculosis.

    PubMed

    Cui, Ze-Jia; Yang, Qing-Yong; Zhang, Hong-Yu; Zhu, Qiang; Zhang, Qing-Ye

    2016-01-01

    Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb). Due to the extensive use of anti-tuberculosis drugs and the development of mutations, the emergence and spread of multidrug-resistant tuberculosis is recognized as one of the most dangerous threats to global tuberculosis control. Some single mutations have been identified to be significantly linked with drug resistance. However, the prior research did not take gene-gene interactions into account, and the emergence of transmissible drug resistance is connected with multiple genetic mutations. In this study we use the bioinformatics software GBOOST (The Hong Kong University, Clear Water Bay, Kowloon, Hong Kong, China) to calculate the interactions of Single Nucleotide Polymorphism (SNP) pairs and identify gene pairs associated with drug resistance. A large part of the non-synonymous mutations in the drug target genes that were included in the screened gene pairs were confirmed by previous reports, which lent sound solid credits to the effectiveness of our method. Notably, most of the identified gene pairs containing drug targets also comprise Pro-Pro-Glu (PPE) family proteins, suggesting that PPE family proteins play important roles in the drug resistance of Mtb. Therefore, this study provides deeper insights into the mechanisms underlying anti-tuberculosis drug resistance, and the present method is useful for exploring the drug resistance mechanisms for other microorganisms. PMID:27618895

  20. Mycobacterium tuberculosis Cluster with Developing Drug Resistance, New York, New York, USA, 2003–2009

    PubMed Central

    Proops, Douglas; Moonan, Patrick K.; Munsiff, Sonal S.; Kreiswirth, Barry N.; Kurepina, Natalia; Goranson, Christopher; Ahuja, Shama D.

    2011-01-01

    In 2004, identification of patients infected with the same Mycobacterium tuberculosis strain in New York, New York, USA, resulted in an outbreak investigation. The investigation involved data collection and analysis, establishing links between patients, and forming transmission hypotheses. Fifty-four geographically clustered cases were identified during 2003–2009. Initially, the M. tuberculosis strain was drug susceptible. However, in 2006, isoniazid resistance emerged, resulting in isoniazid-resistant M. tuberculosis among 17 (31%) patients. Compared with patients with drug-susceptible M. tuberculosis, a greater proportion of patients with isoniazid-resistant M. tuberculosis were US born and had a history of illegal drug use. No patients named one another as contacts. We used patient photographs to identify links between patients. Three links were associated with drug use among patients infected with isoniazid-resistant M. tuberculosis. The photographic method would have been more successful if used earlier in the investigation. Name-based contact investigation might not identify all contacts, particularly when illegal drug use is involved. PMID:21392426

  1. Protocol for studying cough frequency in people with pulmonary tuberculosis

    PubMed Central

    Bravard, Marjory A; Tracey, Brian H; López, José W; Comina, German; Zimic, Mirko; Coronel, Jorge; O'Neill Lee, Gwenyth; Caviedes, Luz; Luis Cabrera, Jose; Salas, Antonio; Ticona, Eduardo; Kirwan, Daniela E; Friedland, Jon S; Evans, Carlton A; Moore, David A; Gilman, Robert H

    2016-01-01

    Introduction Cough is a key symptom of tuberculosis (TB) as well as the main cause of transmission. However, a recent literature review found that cough frequency (number of coughs per hour) in patients with TB has only been studied once, in 1969. The main aim of this study is to describe cough frequency patterns before and after the start of TB treatment and to determine baseline factors that affect cough frequency in these patients. Secondarily, we will evaluate the correlation between cough frequency and TB microbiological resolution. Methods This study will select participants with culture confirmed TB from 2 tertiary hospitals in Lima, Peru. We estimated that a sample size of 107 patients was sufficient to detect clinically significant changes in cough frequency. Participants will initially be evaluated through questionnaires, radiology, microscopic observation drug susceptibility broth TB-culture, auramine smear microscopy and cough recordings. This cohort will be followed for the initial 60 days of anti-TB treatment, and throughout the study several microbiological samples as well as 24 h recordings will be collected. We will describe the variability of cough episodes and determine its association with baseline laboratory parameters of pulmonary TB. In addition, we will analyse the reduction of cough frequency in predicting TB cure, adjusted for potential confounders. Ethics and dissemination Ethical approval has been obtained from the ethics committees at each participating hospital in Lima, Peru, Asociación Benéfica PRISMA in Lima, Peru, the Universidad Peruana Cayetano Heredia in Lima, Peru and Johns Hopkins University in Baltimore, USA. We aim to publish and disseminate our findings in peer-reviewed journals. We also expect to create and maintain an online repository for TB cough sounds as well as the statistical analysis employed. PMID:27105713

  2. Towards host-directed therapies for tuberculosis.

    PubMed

    Zumla, Alimuddin; Maeurer, Markus; Chakaya, Jeremiah; Hoelscher, Michael; Ntoumi, Francine; Rustomjee, Roxana; Vilaplana, Cristina; Yeboah-Manu, Dorothy; Rasolof, Voahangy; Munderi, Paula; Singh, Nalini; Aklillu, Eleni; Padayatchi, Nesri; Macete, Eusebio; Kapata, Nathan; Mulenga, Modest; Kibiki, Gibson; Mfinanga, Sayoki; Nyirenda, Thomas; Maboko, Leonard; Garcia-Basteiro, Alberto; Rakotosamimanana, Niaina; Bates, Matthew; Mwaba, Peter; Reither, Klaus; Gagneux, Sebastien; Edwards, Sarah; Mfinanga, Elirehema; Abdulla, Salim; Cardona, Pere-Joan; Russell, James B W; Gant, Vanya; Noursadeghi, Mahdad; Elkington, Paul; Bonnet, Maryline; Menendez, Clara; Dieye, Tandakha N; Diarra, Bassirou; Maiga, Almoustapha; Aseffa, Abraham; Parida, Shreemanta; Wejse, Christian; Petersen, Eskild; Kaleebu, Pontiano; Oliver, Matt; Craig, Gill; Corrah, Tumena; Tientcheu, Leopold; Antonio, Martin; Rao, Martin; McHugh, Timothy D; Sheikh, Aziz; Ippolito, Giuseppe; Ramjee, Gita; Kaufmann, Stefan H E; Churchyard, Gavin; Steyn, Andrie; Grobusch, Martin; Sanne, Ian; Martinson, Neil; Madansein, Rajhmun; Wilkinson, Robert J; Mayosi, Bongani; Schito, Marco; Wallis, Robert S

    2015-08-01

    The treatment of tuberculosis is based on combinations of drugs that directly target Mycobacterium tuberculosis. A new global initiative is now focusing on a complementary approach of developing adjunct host-directed therapies. PMID:26184493

  3. Tuberculosis, advanced - chest x-rays (image)

    MedlinePlus

    Tuberculosis is an infectious disease that causes inflammation, the formation of tubercules and other growths within tissue, ... death. These chest x-rays show advanced pulmonary tuberculosis. There are multiple light areas (opacities) of varying ...

  4. Effect of mode conversion on defect detection and size estimation in billet from time-of-flight profile by ultrasonic transmission method

    NASA Astrophysics Data System (ADS)

    Miyamoto, Ryusuke; Mizutani, Koichi; Ebihara, Tadashi; Wakatsuki, Naoto

    2016-07-01

    The effect of mode conversion on defect detection and size estimation in a billet from the time-of-flight (TOF) profile is evaluated by comparing the results of wave propagation simulations in an elastic wave field and a scalar wave field, in which only longitudinal waves propagate. As a result, the effect of mode conversion appears in the TOF profile Δτ and received waveform. TOF deviation increases when mode conversion is considered compared with considering only longitudinal waves. This tendency compensates the error in the previous experiment and simulation results. The consideration of the shear components will make simulations and defect size estimations more accurate.

  5. First-Line Anti-Tubercular Drug Resistance of Mycobacterium tuberculosis in IRAN: A Systematic Review

    PubMed Central

    Pourakbari, Babak; Mamishi, Setareh; Mohammadzadeh, Mona; Mahmoudi, Shima

    2016-01-01

    Background: The spread of drug-resistant tuberculosis (TB) is one of the major public health problems through the world. Surveillance of anti-TB drug resistance is essential for monitoring of TB control strategies. The occurrence of drug resistance, particularly multi-drug resistance Mycobacterium tuberculosis (MDR), defined as resistance to at least rifampicin (RIF) and isoniazid (INH), has become a significant public health dilemma. The status of drug-resistance TB in Iran, one of the eastern Mediterranean countries locating between Azerbaijan and Armenia and high-TB burden countries (such as Afghanistan and Pakistan) has been reported inconsistently. Therefore, the aim of this study was to summarize reports of first-line anti-tubercular drug resistance in M. tuberculosis in Iran. Material and Methods: We systematically reviewed published studies on drug-resistant M. tuberculosis in Iran. The search terms were “Mycobacterium tuberculosis susceptibility” or “Mycobacterium tuberculosis resistant” and Iran. Results: Fifty-two eligible articles, published during 1998–2014, were included in this review. Most of the studies were conducted in Tehran. The most common used laboratory method for detecting M. tuberculosis drug resistant was Agar proportion. The highest resistance to first-line drugs was seen in Tehran, the capital city of Iran. The average prevalence of isoniazid (INH), rifampin (RIF), streptomycin (SM), and ethambotol (EMB) resistance via Agar proportion method in Tehran was 26, 23, 22.5, and 16%, respectively. In general, resistance to INH was more common than RIF, SM, and EMB in Tehran Con