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Sample records for estimate tuberculosis transmission

  1. Strain-specific estimation of epidemic success provides insights into the transmission dynamics of tuberculosis

    PubMed Central

    Rasigade, Jean-Philippe; Barbier, Maxime; Dumitrescu, Oana; Pichat, Catherine; Carret, Gérard; Ronnaux-Baron, Anne-Sophie; Blasquez, Ghislaine; Godin-Benhaim, Christine; Boisset, Sandrine; Carricajo, Anne; Jacomo, Véronique; Fredenucci, Isabelle; Pérouse de Montclos, Michèle; Flandrois, Jean-Pierre; Ader, Florence; Supply, Philip; Lina, Gérard; Wirth, Thierry

    2017-01-01

    The transmission dynamics of tuberculosis involves complex interactions of socio-economic and, possibly, microbiological factors. We describe an analytical framework to infer factors of epidemic success based on the joint analysis of epidemiological, clinical and pathogen genetic data. We derive isolate-specific, genetic distance-based estimates of epidemic success, and we represent success-related time-dependent concepts, namely epidemicity and endemicity, by restricting analysis to specific time scales. The method is applied to analyze a surveillance-based cohort of 1,641 tuberculosis patients with minisatellite-based isolate genotypes. Known predictors of isolate endemicity (older age, native status) and epidemicity (younger age, sputum smear positivity) were identified with high confidence (P < 0.001). Long-term epidemic success also correlated with the ability of Euro-American and Beijing MTBC lineages to cause active pulmonary infection, independent of patient age and country of origin. Our results demonstrate how important insights into the transmission dynamics of tuberculosis can be gained from active surveillance data. PMID:28349973

  2. Estimates for local and movement-based transmission of bovine tuberculosis in British cattle.

    PubMed

    Green, Darren M; Kiss, Istvan Z; Mitchell, Andrew P; Kao, Rowland R

    2008-05-07

    Both badgers and livestock movements have been implicated in contributing to the ongoing epidemic of bovine tuberculosis (BTB) in British cattle. However, the relative contributions of these and other causes are not well quantified. We used cattle movement data to construct an individual (premises)-based model of BTB spread within Great Britain, accounting for spread due to recorded cattle movements and other causes. Outbreak data for 2004 were best explained by a model attributing 16% of herd infections directly to cattle movements, and a further 9% unexplained, potentially including spread from unrecorded movements. The best-fit model assumed low levels of cattle-to-cattle transmission. The remaining 75% of infection was attributed to local effects within specific high-risk areas. Annual and biennial testing is mandatory for herds deemed at high risk of infection, as is pre-movement testing from such herds. The herds identified as high risk in 2004 by our model are in broad agreement with those officially designated as such at that time. However, border areas at the edges of high-risk regions are different, suggesting possible areas that should be targeted to prevent further geographical spread of disease. With these areas expanding rapidly over the last decade, their close surveillance is important to both identify infected herds qucikly, and limit their further growth.

  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.

  4. 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

  5. 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.

  6. Transmission and Institutional Infection Control of Tuberculosis.

    PubMed

    Nardell, Edward A

    2015-08-20

    Tuberculosis (TB) transmission control in institutions is evolving with increased awareness of the rapid impact of treatment on transmission, the importance of the unsuspected, untreated case of transmission, and the advent of rapid molecular diagnostics. With active case finding based on cough surveillance and rapid drug susceptibility testing, in theory, it is possible to be reasonably sure that no patient enters a facility with undiagnosed TB or drug resistance. Droplet nuclei transmission of TB is reviewed with an emphasis on risk factors relevant to control. Among environmental controls, natural ventilation and upper-room ultraviolet germicidal ultraviolet air disinfection are the most cost-effective choices, although high-volume mechanical ventilation can also be used. Room air cleaners are generally not recommended. Maintenance is required for all engineering solutions. Finally, personal protection with fit-tested respirators is used in many situations where administrative and engineering methods cannot assure protection.

  7. Progression to active tuberculosis, but not transmission, varies by M. tuberculosis lineage in The Gambia

    PubMed Central

    de Jong, Bouke C.; Hill, Philip C.; Aiken, Alex; Awine, Timothy; Antonio, Martin; Adetifa, Ifedayo M.; Jackson-Sillah, Dolly J.; Fox, Annette; DeRiemer, Kathryn; Gagneux, Sebastien; Borgdorff, Martien W.; McAdam, Keith P.W.J.; Corrah, Tumani; Small, Peter M.; Adegbola, Richard A.

    2008-01-01

    Considerable variability exists in the outcome of M. tuberculosis infection. We hypothesized that M. africanum was less likely than M. tuberculosis to transmit and progress to tuberculosis disease. In a cohort study of tuberculosis patients and their household contacts in the Gambia, we categorized 1,808 HIV negative tuberculosis contacts according to exposure to M. tuberculosis or to M. africanum. A positive skin test indicated transmission and development of tuberculosis during 2 years of follow-up indicated progression to disease. Transmission was similar, but progression to disease was significantly lower in contacts exposed to M. africanum than to M. tuberculosis (1.0% vs 2.9%; Hazard Ratio (HR) 3.1, 95% CI 1.1–8.7). Within M. tuberculosis sensu stricto, contacts exposed to a Beijing family strain were most likely to progress to disease (5.6%; HR 6.7 (2.0–22) relative to M. africanum). M. africanum and M. tuberculosis transmit equally well to household contacts, but contacts exposed to M. africanum are less likely to progress to tuberculosis disease than those exposed to M. tuberculosis. The variable rate of progression by lineage suggests that TB variability matters in clinical settings and should be taken into account in studies evaluating tuberculosis vaccines and treatment regimens for latent tuberculosis infection. PMID:18702608

  8. Transmission of Mycobacterium tuberculosis from Human to Cattle

    PubMed Central

    Ocepek, Matjaž; Pate, Mateja; Žolnir-Dovč, Manca; Poljak, Mario

    2005-01-01

    We describe the first transmission of Mycobacterium tuberculosis from human to cattle confirmed by molecular typing of isolates involved in the transmission. IS6110-based restriction fragment length polymorphism analysis showed that the isolates from the cattle and farm worker who suffered from pulmonary tuberculosis 1 year prior to this case were the same strains. PMID:16000505

  9. Genotypic and Spatial Analysis of Mycobacterium tuberculosis Transmission in a High-Incidence Urban Setting

    PubMed Central

    Ribeiro, Fabíola Karla Correa; Pan, William; Bertolde, Adelmo; Vinhas, Solange Alves; Peres, Renata Lyrio; Riley, Lee; Palaci, Moisés; Maciel, Ethel Leonor

    2015-01-01

    Background. Genotyping Mycobacterium tuberculosis isolates allows study of dynamics of tuberculosis transmission, while geoprocessing allows spatial analysis of clinical and epidemiological data. Here, genotyping data and spatial analysis were combined to characterize tuberculosis transmission in Vitória, Brazil, to identify distinct neighborhoods and risk factors associated with recent tuberculosis transmission. Methods. From 2003 to 2007, 503 isolates were genotyped by IS6110 restriction fragment length polymorphism (RFLP) and spoligotyping. The analysis included kernel density estimation, K-function analysis, and a t test distance analysis. Mycobacterium tuberculosis isolates belonging to identical RFLP patterns (clusters) were considered to represent recent tuberculosis infection (cases). Results. Of 503 genotyped isolates, 242 (48%) were categorized into 70 distinct clusters belonging to 12 RFLP families. The proportion of recent transmission was 34.2%. Kernel density maps indicated 3 areas of intense concentration of cases. K-function analysis of the largest RFLP clusters and families showed they co-localized in space. The distance analysis confirmed these results and demonstrated that unique strain patterns (controls) randomly distributed in space. A logit model identified young age, positive smear test, and lower Index of Quality of Urban Municipality as risk factors for recent transmission. The predicted probabilities for each neighborhood were mapped and identified neighborhoods with high risk for recent transmission. Conclusions. Spatial and genotypic clustering of M. tuberculosis isolates revealed ongoing active transmission of tuberculosis caused by a small subset of strains in specific neighborhoods of the city. Such information provides an opportunity to target tuberculosis transmission control, such as through rigorous and more focused contact investigation programs. PMID:25948063

  10. 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

  11. The Effect of HIV-Related Immunosuppression on the Risk of Tuberculosis Transmission to Household Contacts

    PubMed Central

    Huang, Chuan-Chin; Tchetgen, Eric Tchetgen; Becerra, Mercedes C.; Cohen, Ted; Hughes, Katherine C.; Zhang, Zibiao; Calderon, Roger; Yataco, Rosa; Contreras, Carmen; Galea, Jerome; Lecca, Leonid; Murray, Megan

    2014-01-01

    Background. Coinfection with human immunodeficiency virus (HIV) may modify the risk of transmitting tuberculosis. Some previous investigations suggest that patients coinfected with HIV and tuberculosis are less likely to transmit infection, whereas others do not support this conclusion. Here, we estimated the relative risk of tuberculosis transmission from coinfected patients compared to HIV-negative patients with tuberculosis. Methods. Between September 2009 and August 2012, we identified and enrolled 4841 household contacts of 1608 patients with drug-sensitive tuberculosis in Lima, Peru. We assessed the HIV status and CD4 counts of index patients, as well as other risk factors for infection specific to the index patient, the household, and the exposed individuals. Contacts underwent tuberculin skin testing to determine tuberculosis infection status. Results. After adjusting for covariates, we found that household contacts of HIV-infected tuberculosis patients with a CD4 count ≤250 cells/µL were less likely to be infected with tuberculosis (risk ratio = 0.49 [95% confidence interval, .24–.96]) than the contacts of HIV-negative tuberculosis patients. No children younger than 15 years who were exposed to HIV-positive patients with a CD4 count ≤250 cells/µL were infected with tuberculosis, compared to 22% of those exposed to non-HIV-infected patients. There was no significant difference in the risk of infection between contacts of HIV-infected index patients with CD4 counts >250 cells/µL and contacts of index patients who were not HIV-infected. Conclusions. We found a reduced risk of tuberculosis infection among the household contacts of patients with active tuberculosis who had advanced HIV-related immunosuppression, suggesting reduced transmission from these index patients. PMID:24368620

  12. Transmission dynamics and elimination potential of zoonotic tuberculosis in morocco

    PubMed Central

    Justus Bless, Philipp; Crump, Lisa; Lohmann, Petra; Laager, Mirjam; Chitnis, Nakul; Zinsstag, Jakob

    2017-01-01

    Bovine tuberculosis (BTB) is an endemic zoonosis in Morocco caused by Mycobacterium bovis, which infects many domestic animals and is transmitted to humans through consumption of raw milk or from contact with infected animals. The prevalence of BTB in Moroccan cattle is estimated at 18%, and 33% at the individual and the herd level respectively, but the human M. bovis burden needs further clarification. The current control strategy based on test and slaughter should be improved through local context adaptation taking into account a suitable compensation in order to reduce BTB prevalence in Morocco and decrease the disease burden in humans and animals. We established a simple compartmental deterministic mathematical model for BTB transmission in cattle and humans to provide a general understanding of BTB, in particular regarding transmission to humans. Differential equations were used to model the different pathways between the compartments for cattle and humans. Scenarios of test and slaughter were simulated to determine the effects of varying the proportion of tested animals (p) on the time to elimination of BTB (individual animal prevalence of less than one in a thousand) in cattle and humans. The time to freedom from disease ranged from 75 years for p = 20% to 12 years for p = 100%. For p > 60% the time to elimination was less than 20 years. The cumulated cost was largely stable: for p values higher than 40%, cost ranged from 1.47 to 1.60 billion euros with a time frame of 12 to 32 years to reach freedom from disease. The model simulations also suggest that using a 2mm cut off instead of a 4mm cut off in the Single Intradermal Comparative Cervical Tuberculin skin test (SICCT) would result in cheaper and quicker elimination programs. This analysis informs Moroccan bovine tuberculosis control policy regarding time frame, range of cost and levels of intervention. However, further research is needed to clarify the national human-bovine tuberculosis ratio in Morocco

  13. Transmission of Extensively Drug-Resistant Tuberculosis in South Africa.

    PubMed

    Shah, N Sarita; Auld, Sara C; Brust, James C M; Mathema, Barun; Ismail, Nazir; Moodley, Pravi; Mlisana, Koleka; Allana, Salim; Campbell, Angela; Mthiyane, Thuli; Morris, Natashia; Mpangase, Primrose; van der Meulen, Hermina; Omar, Shaheed V; Brown, Tyler S; Narechania, Apurva; Shaskina, Elena; Kapwata, Thandi; Kreiswirth, Barry; Gandhi, Neel R

    2017-01-19

    Background Drug-resistant tuberculosis threatens recent gains in the treatment of tuberculosis and human immunodeficiency virus (HIV) infection worldwide. A widespread epidemic of extensively drug-resistant (XDR) tuberculosis is occurring in South Africa, where cases have increased substantially since 2002. The factors driving this rapid increase have not been fully elucidated, but such knowledge is needed to guide public health interventions. Methods We conducted a prospective study involving 404 participants in KwaZulu-Natal Province, South Africa, with a diagnosis of XDR tuberculosis between 2011 and 2014. Interviews and medical-record reviews were used to elicit information on the participants' history of tuberculosis and HIV infection, hospitalizations, and social networks. Mycobacterium tuberculosis isolates underwent insertion sequence (IS)6110 restriction-fragment-length polymorphism analysis, targeted gene sequencing, and whole-genome sequencing. We used clinical and genotypic case definitions to calculate the proportion of cases of XDR tuberculosis that were due to inadequate treatment of multidrug-resistant (MDR) tuberculosis (i.e., acquired resistance) versus those that were due to transmission (i.e., transmitted resistance). We used social-network analysis to identify community and hospital locations of transmission. Results Of the 404 participants, 311 (77%) had HIV infection; the median CD4+ count was 340 cells per cubic millimeter (interquartile range, 117 to 431). A total of 280 participants (69%) had never received treatment for MDR tuberculosis. Genotypic analysis in 386 participants revealed that 323 (84%) belonged to 1 of 31 clusters. Clusters ranged from 2 to 14 participants, except for 1 large cluster of 212 participants (55%) with a LAM4/KZN strain. Person-to-person or hospital-based epidemiologic links were identified in 123 of 404 participants (30%). Conclusions The majority of cases of XDR tuberculosis in KwaZulu-Natal, South Africa, an

  14. 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

  15. Measuring ventilation and modelling M. tuberculosis transmission in indoor congregate settings, rural KwaZulu-Natal

    PubMed Central

    Yates, T. A.; Mthethwa, M.; Tanser, F.; Abubakar, I.; Altamirano, H.

    2016-01-01

    SUMMARY SETTING: Molecular epidemiology suggests that most Mycobacterium tuberculosis transmission in high-burden settings occurs outside the home. OBJECTIVE: To estimate the risk of M. tuberculosis transmission inside public buildings in a high TB burden community in KwaZulu-Natal, South Africa. DESIGN: Carbon dioxide (CO2) sensors were placed inside eight public buildings. Measurements were used with observations of occupancy to estimate infection risk using an adaptation of the Wells-Riley equation. Ventilation modelling using CONTAM was used to examine the impact of low-cost retrofits on transmission in a health clinic. RESULTS: Measurements indicate that infection risk in the church, classroom and clinic waiting room would be high with typical ventilation, occupancy levels and visit durations. For example, we estimated that health care workers in a clinic waiting room had a 16.9–24.5% annual risk of M. tuberculosis infection. Modelling results indicate that the simple addition of two new windows allowing for cross-ventilation, at a cost of US$330, would reduce the annual risk to health care workers by 57%. CONCLUSIONS: Results indicate that public buildings in this community have a range of ventilation and occupancy characteristics that may influence transmission risks. Simple retrofits may result in dramatic reductions in M. tuberculosis transmission, and intervention studies should therefore be considered. PMID:27510239

  16. [Tuberculosis transmission in the triple border region: Brazil, Paraguay, and Argentina].

    PubMed

    Braga, José Ueleres; Herrero, Maria Belén; Cuellar, Célia Martinez de

    2011-07-01

    Tuberculosis is a public health problem in South America, but numerous control strategies have proven ineffective in settings with intense transmission. This study aimed to determine whether the triple border region between Brazil, Argentina, and Paraguay is an area of high tuberculosis transmission. An ecological study was conducted with incidence data and population estimates for the three countries. Mean incidence rates were calculated for 2001 to 2007. Spatial analysis techniques identified high-incidence areas in the region using maps with Bayesian smoothing of rates and spatial averages. During the target period, Foz do Iguaçu, Brazil, had the highest incidence, followed by Ciudad del Este in Paraguay, and Puerto Iguazú in Argentina. The analysis showed a spatial cluster of municipalities with high tuberculosis risk in the triple border region. Tuberculosis in the tri-border area shows increasing or stable incidence rates and municipalities with incidence rates above the State average. The area has high tuberculosis incidence and therefore heavy transmission of the disease.

  17. The burden of transmitted multi-drug resistance among epidemics of tuberculosis: A transmission model

    PubMed Central

    Kendall, Emily A.; Fofana, Mariam O.; Dowdy, David W.

    2015-01-01

    Background Multidrug-resistant tuberculosis (MDR-TB) can be acquired through de novo mutation during TB treatment or through transmission from other individuals with active MDR-TB. Understanding the balance between these two mechanisms is essential when allocating resources for MDR-TB. Methods We constructed a dynamic transmission model of an MDR-TB epidemic, allowing for both treatment-related acquisition and person-to-person transmission of resistance. We used national TB notification data to inform Bayesian estimates of the fraction of each country’s 2013 MDR-TB incidence that resulted from MDR transmission rather than treatment-related MDR acquisition. Findings Global estimates of 3·5% MDR-TB prevalence among new TB notifications and 20·5% among retreatment notifications translate into an estimate that resistance transmission rather than acquisition accounts for a median 96% (95% UR: 68–100%) of all incident MDR-TB, and 61% (16–95%) of incident MDR-TB in previously-treated individuals. The estimated percentage of MDR-TB resulting from transmission varied substantially with different countries’ notification data; for example, we estimated this percentage at 48% (30–75%) of MDR-TB in Bangladesh, versus 99% (91–100%) in Uzbekistan. Estimates were most sensitive to estimates of the transmissibility of MDR strains, the probability of acquiring MDR during tuberculosis treatment, and the responsiveness of MDR TB to first-line treatment. Interpretation Notifications of MDR prevalence from most high-burden settings are most consistent with the vast majority of incident MDR-TB resulting from transmission rather than new treatment-related acquisition of resistance. Merely improving the treatment of drug-susceptible TB is unlikely to greatly reduce future MDR-TB incidence. Improved diagnosis and treatment of MDR-TB – including new tests and drug regimens – should be highly prioritized. PMID:26597127

  18. Improving the estimation of the tuberculosis burden in India.

    PubMed

    Cowling, Krycia; Dandona, Rakhi; Dandona, Lalit

    2014-11-01

    Although India is considered to be the country with the greatest tuberculosis burden, estimates of the disease's incidence, prevalence and mortality in India rely on sparse data with substantial uncertainty. The relevant available data are less reliable than those from countries that have recently improved systems for case reporting or recently invested in national surveys of tuberculosis prevalence. We explored ways to improve the estimation of the tuberculosis burden in India. We focused on case notification data - among the most reliable data available - and ways to investigate the associated level of underreporting, as well as the need for a national tuberculosis prevalence survey. We discuss several recent developments - i.e. changes in national policies relating to tuberculosis, World Health Organization guidelines for the investigation of the disease, and a rapid diagnostic test - that should improve data collection for the estimation of the tuberculosis burden in India and elsewhere. We recommend the implementation of an inventory study in India to assess the underreporting of tuberculosis cases, as well as a national survey of tuberculosis prevalence. A national assessment of drug resistance in Indian strains of Mycobacterium tuberculosis should also be considered. The results of such studies will be vital for the accurate monitoring of tuberculosis control efforts in India and globally.

  19. Modeling the Role of Public Transportation in Sustaining Tuberculosis Transmission in South Africa

    PubMed Central

    Andrews, Jason R.; Morrow, Carl; Wood, Robin

    2013-01-01

    Current tuberculosis notification rates in South Africa are among the highest ever recorded. Although the human immunodeficiency virus epidemic has been a critical factor, the density of respiratory contacts in high-risk environments may be an important and underappreciated driver. Using a modified Wells-Riley model for airborne disease transmission, we estimated the risk of tuberculosis transmission on 3 modes of public transit (minibus taxis, buses, and trains) in Cape Town, South Africa, using exhaled carbon dioxide as a natural tracer gas to evaluate air exchange. Carbon dioxide measurements were performed between October and December of 2011. Environmental risk, reflected in the rebreathed fraction of air, was highest in minibus taxis and lowest in trains; however, the average number of passengers sharing an indoor space was highest in trains and lowest in minibus taxis. Among daily commuters, the annual risk of tuberculosis infection was projected to be 3.5%–5.0% and was highest among minibus taxi commuters. Assuming a duration of infectiousness of 1 year, the basic reproductive number attributable to transportation was more than 1 in all 3 modes of transportation. Given its poor ventilation and high respiratory contact rates, public transportation may play a critical role in sustaining tuberculosis transmission in South African cities. PMID:23423215

  20. Modeling the role of public transportation in sustaining tuberculosis transmission in South Africa.

    PubMed

    Andrews, Jason R; Morrow, Carl; Wood, Robin

    2013-03-15

    Current tuberculosis notification rates in South Africa are among the highest ever recorded. Although the human immunodeficiency virus epidemic has been a critical factor, the density of respiratory contacts in high-risk environments may be an important and underappreciated driver. Using a modified Wells-Riley model for airborne disease transmission, we estimated the risk of tuberculosis transmission on 3 modes of public transit (minibus taxis, buses, and trains) in Cape Town, South Africa, using exhaled carbon dioxide as a natural tracer gas to evaluate air exchange. Carbon dioxide measurements were performed between October and December of 2011. Environmental risk, reflected in the rebreathed fraction of air, was highest in minibus taxis and lowest in trains; however, the average number of passengers sharing an indoor space was highest in trains and lowest in minibus taxis. Among daily commuters, the annual risk of tuberculosis infection was projected to be 3.5%-5.0% and was highest among minibus taxi commuters. Assuming a duration of infectiousness of 1 year, the basic reproductive number attributable to transportation was more than 1 in all 3 modes of transportation. Given its poor ventilation and high respiratory contact rates, public transportation may play a critical role in sustaining tuberculosis transmission in South African cities.

  1. Phylogenetic assignment of Mycobacterium tuberculosis Beijing clinical isolates in Japan by maximum a posteriori estimation.

    PubMed

    Seto, Junji; Wada, Takayuki; Iwamoto, Tomotada; Tamaru, Aki; Maeda, Shinji; Yamamoto, Kaori; Hase, Atsushi; Murakami, Koichi; Maeda, Eriko; Oishi, Akira; Migita, Yuji; Yamamoto, Taro; Ahiko, Tadayuki

    2015-10-01

    Intra-species phylogeny of Mycobacterium tuberculosis has been regarded as a clue to estimate its potential risk to develop drug-resistance and various epidemiological tendencies. Genotypic characterization of variable number of tandem repeats (VNTR), a standard tool to ascertain transmission routes, has been improving as a public health effort, but determining phylogenetic information from those efforts alone is difficult. We present a platform based on maximum a posteriori (MAP) estimation to estimate phylogenetic information for M. tuberculosis clinical isolates from individual profiles of VNTR types. This study used 1245 M. tuberculosis clinical isolates obtained throughout Japan for construction of an MAP estimation formula. Two MAP estimation formulae, classification of Beijing family and other lineages, and classification of five Beijing sublineages (ST11/26, STK, ST3, and ST25/19 belonging to the ancient Beijing subfamily and modern Beijing subfamily), were created based on 24 loci VNTR (24Beijing-VNTR) profiles and phylogenetic information of the isolates. Recursive estimation based on the formulae showed high concordance with their authentic phylogeny by multi-locus sequence typing (MLST) of the isolates. The formulae might further support phylogenetic estimation of the Beijing lineage M. tuberculosis from the VNTR genotype with various geographic backgrounds. These results suggest that MAP estimation can function as a reliable probabilistic process to append phylogenetic information to VNTR genotypes of M. tuberculosis independently, which might improve the usage of genotyping data for control, understanding, prevention, and treatment of TB.

  2. 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

  3. Tuberculosis in Cape Town: an age-structured transmission model

    PubMed Central

    Blaser, Nello; Zahnd, Cindy; Hermans, Sabine; Salazar-Vizcaya, Luisa; Estill, Janne; Morrow, Carl; Egger, Matthias; Keiser, Olivia; Wood, Robin

    2015-01-01

    Background Tuberculosis (TB) is the leading cause of death in South Africa. The burden of disease varies by age, with peaks in TB notification rates in the HIV-negative population at ages 0-5, 20-24 and 45-49 years. There is little variation between age groups in the rates in the HIV-positive population. The drivers of this age pattern remain unknown. Methods We developed an age-structured simulation model of Mycobacterium tuberculosis (Mtb) transmission in Cape Town, South Africa. We considered five states of TB progression: susceptible, infected (latent TB), active TB, treated TB and treatment default. Latently infected individuals could be re-infected; a previous Mtb infection slowed progression to active disease. We further considered three states of HIV progression: HIV negative, HIV positive, on antiretroviral therapy. To parameterize the model, we analysed treatment outcomes from the Cape Town electronic TB register, social mixing patterns from a Cape Town community and literature estimates for other parameters. To investigate the main drivers behind the age patterns, we conducted sensitivity analyses on all parameters related to the age structure. Results The model replicated the age patterns in HIV-negative TB notification rates of Cape Town in 2009. Simulated TB notification rate in HIV-negative patients was 1,000/100,000 person-years (pyrs) in children aged < 5 years and decreased to 51/100,000 in children 5-15 years. The peak in early adulthood occurred at 25-29 years (463/100,000 pyrs). After a subsequent decline, simulated TB notification rates gradually increased from the age of 30 years. Sensitivity analyses showed that the dip after the early adult peak was due to the protective effect of latent TB and that retreatment TB was mainly responsible for the rise in TB notification rates from the age of 30 years. Conclusion The protective effect of a first latent infection on subsequent infections and the faster progression in previously treated patients

  4. Evidence of transmission of tuberculosis by DNA fingerprinting.

    PubMed Central

    Godfrey-Faussett, P.; Mortimer, P. R.; Jenkins, P. A.; Stoker, N. G.

    1992-01-01

    OBJECTIVE--To determine whether a subject who had died of tuberculous meningitis had been infected by a neighbour. DESIGN--Retrospective comparison of isolates of Mycobacterium tuberculosis from the two cases and from 10 controls by DNA fingerprinting. SETTING--Public Health Service Reference Laboratory for Mycobacteria and bacterial molecular genetics unit of the London School of Hygiene and Tropical Medicine. SUBJECTS--Deceased and neighbour; 10 controls from the same city, from whom isolates had been collected over three months before the subject's death. MAIN OUTCOME MEASURES--Identity and similarity values (SAB) between fingerprint patterns from different isolates obtained by hybridisation of restriction fragments produced by PvuII with a probe from the insertion element IS6110/986, present in multiple copies throughout the genome of M tuberculosis. RESULTS--Isolates from the two cases under investigation had identical fingerprints whereas those from the controls were all distinct. Two clusters of isolates with a similarity coefficient > 0.25 were identified: in one, four out of five patients were born in the midlands (the birth place of the fifth was not known) and in the other all three patients were born in the Indian subcontinent. CONCLUSIONS--The data are consistent with, but do not prove, transmission of tuberculosis from the neighbour to the deceased. Geographical separation of the pools of infection may have led to the evolution of distinct clusters of fingerprint patterns. DNA fingerprinting of M tuberculosis is a powerful new tool for study of the epidemiology and pathogenesis of tuberculosis. Images FIG 1 PMID:1392824

  5. First case of Mycobacterium tuberculosis transmission by heart transplantation from donor to recipient.

    PubMed

    Weile, Jan; Eickmeyer, Holm; Dreier, Jens; Liebke, Michael; Fuchs, Uwe; Wittke, Johann-Wolfgang; Richter, Elvira; Gummert, Jan; Knabbe, Cornelius; Schulz, Uwe

    2013-12-01

    We report the first documented case of a Mycobacterium tuberculosis transmission by an orthotopic heart transplantation from the donor to the recipient. Mycobacterium tuberculosis positive blood culture showed systemic prevalence of the Mycobacteria, however, prophylactic therapy was able to prevent a clinical manifestation of tuberculosis in the recipient.

  6. Mycobacterium tuberculosis transmission in a country with low tuberculosis incidence: role of immigration and HIV infection.

    PubMed

    Fenner, Lukas; Gagneux, Sebastien; Helbling, Peter; Battegay, Manuel; Rieder, Hans L; Pfyffer, Gaby E; Zwahlen, Marcel; Furrer, Hansjakob; Siegrist, Hans H; Fehr, Jan; Dolina, Marisa; Calmy, Alexandra; Stucki, David; Jaton, Katia; Janssens, Jean-Paul; Stalder, Jesica Mazza; Bodmer, Thomas; Ninet, Beatrice; Böttger, Erik C; Egger, Matthias

    2012-02-01

    Immigrants from high-burden countries and HIV-coinfected individuals are risk groups for tuberculosis (TB) in countries with low TB incidence. Therefore, we studied their role in transmission of Mycobacterium tuberculosis in Switzerland. We included all TB patients from the Swiss HIV Cohort and a sample of patients from the national TB registry. We identified molecular clusters by spoligotyping and mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analysis and used weighted logistic regression adjusted for age and sex to identify risk factors for clustering, taking sampling proportions into account. In total, we analyzed 520 TB cases diagnosed between 2000 and 2008; 401 were foreign born, and 113 were HIV coinfected. The Euro-American M. tuberculosis lineage dominated throughout the study period (378 strains; 72.7%), with no evidence for another lineage, such as the Beijing genotype, emerging. We identified 35 molecular clusters with 90 patients, indicating recent transmission; 31 clusters involved foreign-born patients, and 15 involved HIV-infected patients. Birth origin was not associated with clustering (adjusted odds ratio [aOR], 1.58; 95% confidence interval [CI], 0.73 to 3.43; P = 0.25, comparing Swiss-born with foreign-born patients), but clustering was reduced in HIV-infected patients (aOR, 0.49; 95% CI, 0.26 to 0.93; P = 0.030). Cavitary disease, male sex, and younger age were all associated with molecular clustering. In conclusion, most TB patients in Switzerland were foreign born, but transmission of M. tuberculosis was not more common among immigrants and was reduced in HIV-infected patients followed up in the national HIV cohort study. Continued access to health services and clinical follow-up will be essential to control TB in this population.

  7. Malaria transmission rates estimated from serological data.

    PubMed Central

    Burattini, M. N.; Massad, E.; Coutinho, F. A.

    1993-01-01

    A mathematical model was used to estimate malaria transmission rates based on serological data. The model is minimally stochastic and assumes an age-dependent force of infection for malaria. The transmission rates estimated were applied to a simple compartmental model in order to mimic the malaria transmission. The model has shown a good retrieving capacity for serological and parasite prevalence data. PMID:8270011

  8. 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.

  9. Estimation of tuberculosis risk on a commercial airliner.

    PubMed

    Ko, Gwangpyo; Thompson, Kimberly M; Nardell, Edward A

    2004-04-01

    This article estimates the risk of tuberculosis (TB) transmission on a typical commercial airliner using a simple one box model (OBM) and a sequential box model (SBM). We used input data derived from an actual TB exposure on an airliner, and we assumed a hypothetical scenario that a highly infectious TB source case (i.e., 108 infectious quanta per hour) travels as a passenger on an 8.7-hour flight. We estimate an average risk of TB transmission on the order of 1 chance in 1,000 for all passengers using the OBM. Applying the more realistic SBM, we show that the risk and incidence decrease sharply in a stepwise fashion in cabins downstream from the cabin containing the source case assuming some potential for airflow from more contaminated to less contaminated cabins. We further characterized spatial variability in the risk within the cabin by modeling a previously reported TB outbreak in an airplane to demonstrate that the TB cases occur most likely within close proximity of the source TB patient.

  10. Confirming Mycobacterium tuberculosis transmission from a cadaver to an embalmer using molecular epidemiology.

    PubMed

    Anderson, Janelle A; Meissner, Jeanne Sullivan; Ahuja, Shama Desai; Shashkina, Elena; O'Flaherty, Tholief; Proops, Douglas C

    2015-05-01

    Genotyping results and epidemiologic investigation were used to confirm tuberculosis transmission from a cadaver to an embalmer. This investigation highlights the utility of genotyping in identifying unsuspected epidemiologic links and unusual transmission settings. In addition, the investigation provides additional evidence for the occupational risk of tuberculosis among funeral service workers and indicates a need for education about tuberculosis risk and the importance of adhering to appropriate infection control measures among funeral service workers.

  11. 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

  12. Application of DNA markers to estimate genetic diversity of Mycobacterium tuberculosis strains.

    PubMed

    Korzekwa, Karol; Polok, Kornelia; Zieliński, Roman

    2006-01-01

    The obligatory human pathogen, Mycobacterium tuberculosis, is the most important etiological factor of tuberculosis. Unfortunately, there is little information about genetic diversity of this pathogen. The main aim of this research was the estimation of genetic diversity of M. tuberculosis on the basis of various categories of DNA markers. The genome of 32 strains were scanned by DNA markers such RAPD, IS6110 and catalase-peroxidase katG gene. All 162 identified loci were polymorphic. The genetic diversity coefficient (HT) of M. tuberculosis was 0.32 for RAPD and 0.27 for IS 6110. There were 14 alleles in katG gene. All strains were characterised by the individual molecular pattern. Genetic similarity varied from 0.13 to 0.94 (RAPD markers) and from 0 to 1 for (IS6110). M. tuberculosis strains did not represent a clonal structure, single source of transmission and epidemiological relationships as well. The applied DNA markers proved to be highly efficient for analysis of genetic structure of M. tuberculosis.

  13. The transmission of tuberculosis in schools involving children 3 to 11 years of age.

    PubMed

    Roberts, Jonathan R; Mason, Brendan W; Paranjothy, Shantini; Palmer, Stephen R

    2012-01-01

    Little is known about the risk of tuberculosis transmission from children. We reviewed the published literature on the transmission of tuberculosis during outbreaks involving children 3 to 11 years of age and report that transmission rates among close contacts in school outbreaks are on average higher (weighted average 69.8% vs. 39.3%) if the index case is a child than an adult.

  14. Seasonality Impact on the Transmission Dynamics of Tuberculosis.

    PubMed

    Yang, Yali; Guo, Chenping; Liu, Luju; Zhang, Tianhua; Liu, Weiping

    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.

  15. 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.

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

    PubMed Central

    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

    2015-01-01

    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 m2 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

  17. 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 ...

  18. Tuberculosis transmission in Northwest of Iran: using MIRU-VNTR, ETR-VNTR and IS6110-RFLP methods.

    PubMed

    Asgharzadeh, Mohammad; Kafil, Hossein Samadi; Roudsary, Ali Amoghi; Hanifi, Gholam Reza

    2011-01-01

    Tuberculosis is the main cause for adults' death from a single infectious agent killing about 2 million people every year. Identifying the source of transmission infection is necessary to decrease tuberculosis. In this study we used IS6110-RFLP, MIRU-VNTR and ETR-VNTR methods to determine transmission dynamic of tuberculosis in Northwest of Iran from March 2004 to March 2005. 156 culture positive isolates (51 from Orumieh and 105 from Tabriz) were collected. IS6110-RFLP was done by standardized method and MIRU-VNTR was done by 12 primers specific for 12 MIRU-VNTR loci by polymerase chain reaction and ETR was carried out by primers specific for ETR-A, ETR-B and ETR-C as well. Genetic relationship analyses were performed by MVSP software and MIRU-VNTRplus website. The results revealed that the copy number of IS6110 in isolates ranged from 0 to 17. One hundred and seven unique patterns and 16 shared patterns by 2-10 isolates were determined by IS6110-RFLP, and 116 distinct patterns were identified by MIRU-VNTR including 21 clustered patterns and 95 unique patterns. Having combined MIRU-VNTR and ETR-VNTR data, we increased the discriminatory power of typing method, thus 25 clusters were identified. Loci 10, 26, 40 in MIRU and ETR-A were highly discriminatory. Distribution of lineages in our study according to tentative data in MIRU-VNTRplus database was multi-matches 9.09%, Bovis 9.74%, S 8.44%, New-1 0.65%, Uganda I 0.65%, Haarlem 0.65%, Cameroon 0.65% and X 0.65%. The minimum estimate for tuberculosis proportion due to transmission was 20.1% with IS6110-RFLP and was 18.8% with MIRU and ETR. In conclusion, tuberculosis sanitation status in northwest of Iran due to minimum estimate of tuberculosis transmission was satisfactory, and the reactivation of tuberculosis was responsible for more than 80% of new tuberculosis. According to the results and drawbacks of IS6110-RFLP method we strongly recommend MIRU-VNTRplus ETR-VNTR as an easy, reliable, reproducible and highly

  19. Role of casual contacts in the recent transmission of tuberculosis in settings with high disease burden

    PubMed Central

    Wang, Weibing; Mathema, Barun; Hu, Yi; Zhao, Qi; Weili, Jiang; Xu, Biao

    2014-01-01

    Tuberculosis (TB) remains a major cause of morbidity and mortality worldwide. It is expected that combining multiple molecular methods will further help in focusing contact investigations. We performed a population-based molecular epidemiologic study in 6 sites in China between 1 June 2009 and 31 December 2010. A genotyping method combining 7-loci MIRU-VNTR and IS6110-based RFLP was employed to determine predictors of recent transmission. A second interview was performed with the clustered patients to identify potential epidemiological links. The molecular clustering analysis revealed that 187 isolates (15.3%) were clustered by sharing identical VNTR-IS6110 combined patterns, with an estimated recent transmission index being 8.9%. None of these patients reported having contacts with other members within the same cluster. Nineteen of 121 reported having a history of contact to a TB case within 2 years before the current TB diagnosis. Additionally, geographic correlation was established for 19 cases in 9 clusters, while only one possible epidemiological link was established in secondary interview. The results underscore the role of casual contact or reactivation of latent TB as a driving factor maintaining the current endemicity in rural China with high disease burdens of tuberculosis. PMID:24941878

  20. 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

    2012-07-20

    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.

  1. [Tuberculosis surveys in Guerrero and new estimates of the magnitude of tuberculosis infection in Mexico].

    PubMed

    Cárdenas-Ayala, V M; Bernal-Pérez, J; Cabrera-Coello, L; Stetler, H C; Pineda-Salgado, J; Guerrero-Reyes, P

    1989-01-01

    Tuberculosis infection surveys are carried out by tuberculin skin test (Mantoux) which is a simple, cheap, valid and reliable procedure for the estimation of prevalence and incidence rates. In 1987 a survey was undertaken in children of 6-7 years old who attended the elementary school and who were not vaccinated (BCG) in the region of Iguala, México. Out of 6,095 children of such age group, just 531 were not vaccinated, thus the prevalence figure was 2.5% (CL05 = 0.1%, 5.3%). On the basis of the findings by Izaguirre et al, 26 years ago, who reported that about 10% of the children of this age group were infected, it can be estimated that the annual risk of infection is about three newly infected each year per 1,000 population. It is necessary to provide better estimates of the whole tuberculosis incidence rate.

  2. 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.

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

    PubMed

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

    2012-06-12

    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.

  4. 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

  5. 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

  6. 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.

  7. 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.

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

    PubMed

    Nebenzahl-Guimaraes, Hanna; Verhagen, Lilly M; Borgdorff, Martien W; van Soolingen, Dick

    2015-10-01

    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.

  9. 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

  10. Estimating tuberculosis incidence from primary survey data: a mathematical modeling approach

    PubMed Central

    Chadha, V. K.; Laxminarayan, R.; Arinaminpathy, N.

    2017-01-01

    SUMMARY BACKGROUND: There is an urgent need for improved estimations of the burden of tuberculosis (TB). OBJECTIVE: To develop a new quantitative method based on mathematical modelling, and to demonstrate its application to TB in India. DESIGN: We developed a simple model of TB transmission dynamics to estimate the annual incidence of TB disease from the annual risk of tuberculous infection and prevalence of smear-positive TB. We first compared model estimates for annual infections per smear-positive TB case using previous empirical estimates from China, Korea and the Philippines. We then applied the model to estimate TB incidence in India, stratified by urban and rural settings. RESULTS: Study model estimates show agreement with previous empirical estimates. Applied to India, the model suggests an annual incidence of smear-positive TB of 89.8 per 100 000 population (95%CI 56.8–156.3). Results show differences in urban and rural TB: while an urban TB case infects more individuals per year, a rural TB case remains infectious for appreciably longer, suggesting the need for interventions tailored to these different settings. CONCLUSIONS: Simple models of TB transmission, in conjunction with necessary data, can offer approaches to burden estimation that complement those currently being used. PMID:28284250

  11. The risk of tuberculosis transmission to free-ranging great apes.

    PubMed

    Wolf, Tiffany M; Sreevatsan, Srinand; Travis, Dominic; Mugisha, Lawrence; Singer, Randall S

    2014-01-01

    Pathogen exchange between humans and primates has been facilitated by anthropogenic disturbances, such as changing land use patterns, habitat destruction, and poaching, which decrease population sizes and increase levels of primate-human interaction. As a result, human and domestic animal diseases have become a recognized threat to endangered primate populations. Tuberculosis is a major global human and animal health concern, especially in equatorial Africa where many of the remaining free-living great ape populations exist in proximity with exposed and/or infected human populations and their domestic animals. Increased anthropogenic pressure creates an opportunity for the anthropozoonotic spread of this disease. This review examines current evidence of the risk of tuberculosis transmission to great apes, the benefits and limitations of current detection methods, the impact of current great ape conservation and management strategies on this risk, and the need for an ecosystem health-based approach to mitigating the risks of tuberculosis transmission to great apes.

  12. Mycobacterium tuberculosis complex transmission is not associated with recent immigration (≤5 years) in Florida.

    PubMed

    Séraphin, Marie Nancy; Lauzardo, Michael

    2015-12-01

    As tuberculosis (TB) incidence decreases in the US, foreign-born persons continue to account for a larger proportion of the burden. In these cross-sectional analyses of 1149 culture-confirmed TB cases genotyped using spoligotyping and 24-locus MIRU, we show that over a quarter of cases among the foreign-born population in Florida resulted from recent transmission of the Mycobacterium tuberculosis complex. In addition, over a third of these cases occurred among persons who had immigrated 5 years or less prior to their diagnosis. Although recent immigration was not a significant predictor of TB transmission, younger age, birthplace in the Americas, homelessness, drug use and TB lineage are risk factors for TB transmission among the foreign-born population in Florida. These data provide actionable insights into TB transmission among the foreign-born population in Florida.

  13. Virulence, immunopathology and transmissibility of selected strains of Mycobacterium tuberculosis in a murine model

    PubMed Central

    Marquina-Castillo, Brenda; García-García, Lourdes; Ponce-de-León, Alfredo; Jimenez-Corona, Maria-Eugenia; Bobadilla-del Valle, Miriam; Cano-Arellano, Bulmaro; Canizales-Quintero, Sergio; Martinez-Gamboa, Areli; Kato-Maeda, Midori; Robertson, Brian; Young, Douglas; Small, Peter; Schoolnik, Gary; Sifuentes-Osornio, Jose; Hernandez-Pando, Rogelio

    2009-01-01

    After encounter with Mycobacterium tuberculosis, a series of non-uniform immune responses are triggered that define the course of the infection. Eight M. tuberculosis strains were selected from a prospective population-based study of pulmonary tuberculosis patients (1995–2003) based on relevant clinical/epidemiological patterns and tested in a well-characterized BALB/c mouse model of progressive pulmonary tuberculosis. In addition, a new mouse model of transmissibility consisting of prolonged cohousing (up to 60 days) of infected and naïve animals was tested. Four phenotypes were defined based on strain virulence (mouse survival, lung bacillary load and tissue damage), immunology response (cytokine expression determined by real-time polymerase chain reaction) and transmissibility (lung bacillary loads and cutaneous delayed-type hypersensitivity in naïve animals).We identified four clearly defined strain phenotypes: (1) hypervirulent strain with non-protective immune response and highly transmissible; (2) virulent strain, associated with high expression of proinflammatory cytokines (tumour necrosis factor and interferon) and very low anti-inflammatory cytokine expression (interleukins 4 and 10), which induced accelerated death by immunopathology; (3) strain inducing efficient protective immunity with lower virulence, and (4) strain demonstrating strong and early macrophage activation (innate immunity) with delayed participation of acquired immunity (interferon expression). We were able to correlate virulent and transmissible phenotypes in the mouse model and markers of community transmission such as tuberculin reactivity among contacts, rapid progression to disease and cluster status. However, we were not able to find correlation with the other two phenotypes. Our new transmission model supported the hypothesis that among these strains increased virulence was linked to increased transmission. PMID:19191912

  14. 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.

  15. Mycobacterium tuberculosis Transmission among Elderly Persons, Yamagata Prefecture, Japan, 2009–2015

    PubMed Central

    Wada, Takayuki; Suzuki, Yu; Ikeda, Tatsuya; Mizuta, Katsumi; Yamamoto, Taro; Ahiko, Tadayuki

    2017-01-01

    In many countries with low to moderate tuberculosis (TB) incidence, cases have shifted to elderly persons. It is unclear, however, whether these cases are associated with recent Mycobacterium tuberculosis transmissionor represent reactivation of past disease. During 2009–2015, we performed a population-based TB investigation in Yamagata Prefecture, Japan, using in-depth contact tracing and 24-loci variable-number tandem-repeat typing optimized for Beijing family M. tuberculosis strains. We analyzed 494 strains, of which 387 (78.3%) were derived from elderly patients. Recent transmission with an epidemiologic link was confirmed in 22 clusters (70 cases). In 17 (77.3%) clusters, the source patient was elderly; 11 (64.7%) of the 17 clusters occurred in a hospital or nursing home. In this setting, the increase in TB cases was associated with M. tuberculosis transmissions from elderly persons. Prevention of transmission in places where elderly persons gather will be an effective strategy for decreasing TB incidence among predominantly elderly populations. PMID:28221133

  16. 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

  17. Mathematical analysis of tuberculosis transmission model with delay

    NASA Astrophysics Data System (ADS)

    Lapaan, R. D.; Collera, J. A.; Addawe, J. M.

    2016-11-01

    In this paper, a delayed Tuberculosis infection model is formulated and investigated. We showed the existence of disease free equilibrium and endemic equilibrium points. We used La Salle-Lyapunov Invariance Principle to show that if the reproductive number R0 < 1, the disease-free equilibrium of the model is globally asymptotically stable. Numerical simulations are then performed to illustrate the existence of the disease free equilibrium and the endemic equilibrium point for a given value of R0. Thus, when R0 < 1, the disease dies out in the population.

  18. Tuberculosis

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Tuberculosis KidsHealth > For Teens > Tuberculosis A A A What's in this article? TB ... Duration When to Call the Doctor en español Tuberculosis TB Basics Tuberculosis (also known as "TB") is ...

  19. Tuberculosis

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Tuberculosis KidsHealth > For Teens > Tuberculosis Print A A A What's in this article? ... Duration When to Call the Doctor en español Tuberculosis TB Basics Tuberculosis (also known as "TB") is ...

  20. 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

  1. Recent transmission of drug-resistant Mycobacterium tuberculosis in a prison population in southern Brazil.

    PubMed

    Reis, Ana Julia; David, Simone Maria Martini de; Nunes, Luciana de Souza; Valim, Andreia Rosane de Moura; Possuelo, Lia Gonçalves

    2016-01-01

    We conducted a cross-sectional, retrospective study, characterized by classical and molecular epidemiology, involving M. tuberculosis isolates from a regional prison in southern Brazil. Between January of 2011 and August of 2014, 379 prisoners underwent sputum smear microscopy and culture; 53 (13.9%) were diagnosed with active tuberculosis. Of those, 8 (22.9%) presented with isoniazid-resistant tuberculosis. Strain genotyping was carried out by 15-locus mycobacterial interspersed repetitive unit-variable-number tandem-repeat analysis; 68.6% of the patients were distributed into five clusters, and 87.5% of the resistant cases were in the same cluster. The frequency of drug-resistant tuberculosis cases and the rate of recent transmission were high. Our data suggest the need to implement an effective tuberculosis control program within the prison system. RESUMO Estudo transversal, retrospectivo, com isolados de M. tuberculosis de pacientes de um presídio regional no sul do Brasil, caracterizado através de epidemiologia clássica e molecular. Entre janeiro de 2011 e agosto de 2014, 379 detentos foram submetidos a baciloscopia e cultura, sendo 53 (13,9%) diagnosticados com tuberculose ativa. Desses, 8 (22,9%) apresentavam tuberculose resistente a isoniazida. A genotipagem das cepas foi realizada por 15-locus mycobacterial interspersed repetitive units-variable number of tandem repeat analysis; 68,6% dos pacientes estavam distribuídos em cinco clusters, e 87,5% dos casos resistentes estavam em um mesmo cluster. Verificou-se uma frequência elevada de casos de resistência e alta taxa de transmissão recente. Estes dados sugerem a necessidade da implantação de um programa efetivo de controle da tuberculose no sistema prisional.

  2. Genetic diversity, transmission dynamics and drug resistance of Mycobacterium tuberculosis in Angola

    PubMed Central

    Perdigão, João; Clemente, Sofia; Ramos, Jorge; Masakidi, Pedro; Machado, Diana; Silva, Carla; Couto, Isabel; Viveiros, Miguel; Taveira, Nuno; Portugal, Isabel

    2017-01-01

    Tuberculosis (TB) poses a serious public health problem in Angola. No surveillance data on drug resistance is available and nothing is known regarding the genetic diversity and population structure of circulating Mycobacterium tuberculosis strains. Here, we have genotyped and evaluated drug susceptibility of 89 Mycobacterium tuberculosis clinical isolates from Luanda. Thirty-three different spoligotype profiles corresponding to 24 different Shared International Types (SIT) and 9 orphan profiles were detected. SIT 20 (LAM1) was the most prevalent (n = 16, 18.2%) followed by SIT 42 (LAM9; n = 15, 17.1%). Overall, the M. tuberculosis population structure in this sample was dominated by LAM (64.8%) and T (33.0%) strains. Twenty-four-loci MIRU-VNTR analysis revealed that a total of 13 isolates were grouped in 5 distinct clusters. Drug susceptibility data showed that 22 (24.7%) of the 89 clinical isolates were resistant to one or more antibacillary drugs of which 4 (4.5%) were multidrug resistant. In conclusion, this study demonstrates a high predominance of LAM strains circulating in the Luanda setting and the presence of recent transmission events. The rate and the emergence dynamics of drug resistant TB found in this sample are significant and highlight the need of further studies specifically focused on MDR-TB transmission. PMID:28230095

  3. Genetic diversity, transmission dynamics and drug resistance of Mycobacterium tuberculosis in Angola.

    PubMed

    Perdigão, João; Clemente, Sofia; Ramos, Jorge; Masakidi, Pedro; Machado, Diana; Silva, Carla; Couto, Isabel; Viveiros, Miguel; Taveira, Nuno; Portugal, Isabel

    2017-02-23

    Tuberculosis (TB) poses a serious public health problem in Angola. No surveillance data on drug resistance is available and nothing is known regarding the genetic diversity and population structure of circulating Mycobacterium tuberculosis strains. Here, we have genotyped and evaluated drug susceptibility of 89 Mycobacterium tuberculosis clinical isolates from Luanda. Thirty-three different spoligotype profiles corresponding to 24 different Shared International Types (SIT) and 9 orphan profiles were detected. SIT 20 (LAM1) was the most prevalent (n = 16, 18.2%) followed by SIT 42 (LAM9; n = 15, 17.1%). Overall, the M. tuberculosis population structure in this sample was dominated by LAM (64.8%) and T (33.0%) strains. Twenty-four-loci MIRU-VNTR analysis revealed that a total of 13 isolates were grouped in 5 distinct clusters. Drug susceptibility data showed that 22 (24.7%) of the 89 clinical isolates were resistant to one or more antibacillary drugs of which 4 (4.5%) were multidrug resistant. In conclusion, this study demonstrates a high predominance of LAM strains circulating in the Luanda setting and the presence of recent transmission events. The rate and the emergence dynamics of drug resistant TB found in this sample are significant and highlight the need of further studies specifically focused on MDR-TB transmission.

  4. 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.

  5. 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.

  6. Problems connected with estimating the incidence of tuberculosis infection*

    PubMed Central

    Narain, Raj; Nair, S. S.; Chandrasekhar, P.; Rao, G. Ramanatha

    1966-01-01

    Many problems have to be faced in the estimation of an apparently simple but valuable index—namely, the incidence of tuberculosis infection. Very little attention seems to have been paid to these problems so far. Records from 50 villages in a district of South India, whose populations were tested with 1 TU of PPD RT 23 in Tween 80 diluent and retested after 18 months, have been examined for a reappraisal of existing methods. As a result, it has been found that some of these methods are subject to gross errors and that available figures are unreliable. For estimating the newly infected, a new approach based on the drawing of a curve for the distribution of differences in reaction size from one round of tuberculin testing to another is presented. Further, it is shown that the newly infected probably constitute a homogeneous group with an increase in mean reaction size of about 24 mm and standard deviation of 4 mm. Accordingly, 98% of the newly infected show an increase in reaction size of 16 mm or more. There are others who show similarly large increases in allergy on a retest, even in the absence of infection. The number of persons in the latter category rises with age and is likely to be greater in areas with a high prevalence of non-specific allergy. PMID:5296384

  7. Whole Genome Sequencing Demonstrates Limited Transmission within Identified Mycobacterium tuberculosis Clusters in New South Wales, Australia

    PubMed Central

    Gurjav, Ulziijargal; Outhred, Alexander C.; Jelfs, Peter; McCallum, Nadine; Wang, Qinning; Hill-Cawthorne, Grant A.; Marais, Ben J.; Sintchenko, Vitali

    2016-01-01

    Australia has a low tuberculosis incidence rate with most cases occurring among recent immigrants. Given suboptimal cluster resolution achieved with 24-locus mycobacterium interspersed repetitive unit (MIRU-24) genotyping, the added value of whole genome sequencing was explored. MIRU-24 profiles of all Mycobacterium tuberculosis culture-confirmed tuberculosis cases diagnosed between 2009 and 2013 in New South Wales (NSW), Australia, were examined and clusters identified. The relatedness of cases within the largest MIRU-24 clusters was assessed using whole genome sequencing and phylogenetic analyses. Of 1841 culture-confirmed TB cases, 91.9% (1692/1841) had complete demographic and genotyping data. East-African Indian (474; 28.0%) and Beijing (470; 27.8%) lineage strains predominated. The overall rate of MIRU-24 clustering was 20.1% (340/1692) and was highest among Beijing lineage strains (35.7%; 168/470). One Beijing and three East-African Indian (EAI) clonal complexes were responsible for the majority of observed clusters. Whole genome sequencing of the 4 largest clusters (30 isolates) demonstrated diverse single nucleotide polymorphisms (SNPs) within identified clusters. All sequenced EAI strains and 70% of Beijing lineage strains clustered by MIRU-24 typing demonstrated distinct SNP profiles. The superior resolution provided by whole genome sequencing demonstrated limited M. tuberculosis transmission within NSW, even within identified MIRU-24 clusters. Routine whole genome sequencing could provide valuable public health guidance in low burden settings. PMID:27737005

  8. 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

  9. Multi-state modelling reveals sex-dependent transmission, progression and severity of tuberculosis in wild badgers.

    PubMed

    Graham, J; Smith, G C; Delahay, R J; Bailey, T; McDonald, R A; Hodgson, D

    2013-07-01

    Statistical models of epidemiology in wildlife populations usually consider diseased individuals as a single class, despite knowledge that infections progress through states of severity. Bovine tuberculosis (bTB) is a serious zoonotic disease threatening the UK livestock industry, but we have limited understanding of key epidemiological processes in its wildlife reservoirs. We estimated differential survival, force of infection and progression in disease states in a population of Eurasian badgers (Meles meles), naturally infected with bTB. Our state-dependent models overturn prevailing categorizations of badger disease states, and find novel evidence for early onset of disease-induced mortality in male but not female badgers. Males also have higher risk of infection and more rapid disease progression which, coupled with state-dependent increases in mortality, could promote sex biases in the risk of transmission to cattle. Our results reveal hidden complexities in wildlife disease epidemiology, with implications for the management of TB and other zoonotic diseases.

  10. Usefulness of molecular techniques to identify ongoing tuberculosis transmission in Saudi Arabia.

    PubMed

    Al-Hajoj, Sahal A; Mohammed, Viqaruddin K; Al-Hokail, Abdullah A

    2007-02-01

    This study represents the first time that molecular tracing techniques have been used to identify patterns of tuberculosis TB infection in Saudi Arabia. The 2 strains were isolated from a socio-economically advantage family who share a number of common facilities including a car and a driver. There are several factors that may play vital roles in on-going transmission of TB in Saudi Arabia including a high number of expatriates, the Hajj pilgrimage, and the social habits of Saudi citizens. Our sibling case series is believed to be a frequent pattern of disease transmission in this country. Control measures such as health education, active case finding, and prompt and supervised medical treatment are needed. More studies using molecular techniques are recommended to find the incidence of cross infection in Saudi Arabia. In addition, molecular techniques have to be established in all reference laboratories to help the detection of ongoing active transmission, molecular epidemiology and detect sources of infection.

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

    PubMed Central

    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

    2016-01-01

    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

  12. The epidemiology, pathogenesis, transmission, diagnosis, and management of multidrug-resistant, extensively drug-resistant, and incurable tuberculosis.

    PubMed

    Dheda, Keertan; Gumbo, Tawanda; Maartens, Gary; Dooley, Kelly E; McNerney, Ruth; Murray, Megan; Furin, Jennifer; Nardell, Edward A; London, Leslie; Lessem, Erica; Theron, Grant; van Helden, Paul; Niemann, Stefan; Merker, Matthias; Dowdy, David; Van Rie, Annelies; Siu, Gilman K H; Pasipanodya, Jotam G; Rodrigues, Camilla; Clark, Taane G; Sirgel, Frik A; Esmail, Aliasgar; Lin, Hsien-Ho; Atre, Sachin R; Schaaf, H Simon; Chang, Kwok Chiu; Lange, Christoph; Nahid, Payam; Udwadia, Zarir F; Horsburgh, C Robert; Churchyard, Gavin J; Menzies, Dick; Hesseling, Anneke C; Nuermberger, Eric; McIlleron, Helen; Fennelly, Kevin P; Goemaere, Eric; Jaramillo, Ernesto; Low, Marcus; Jara, Carolina Morán; Padayatchi, Nesri; Warren, Robin M

    2017-03-15

    Global tuberculosis incidence has declined marginally over the past decade, and tuberculosis remains out of control in several parts of the world including Africa and Asia. Although tuberculosis control has been effective in some regions of the world, these gains are threatened by the increasing burden of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. XDR tuberculosis has evolved in several tuberculosis-endemic countries to drug-incurable or programmatically incurable tuberculosis (totally drug-resistant tuberculosis). This poses several challenges similar to those encountered in the pre-chemotherapy era, including the inability to cure tuberculosis, high mortality, and the need for alternative methods to prevent disease transmission. This phenomenon mirrors the worldwide increase in antimicrobial resistance and the emergence of other MDR pathogens, such as malaria, HIV, and Gram-negative bacteria. MDR and XDR tuberculosis are associated with high morbidity and substantial mortality, are a threat to health-care workers, prohibitively expensive to treat, and are therefore a serious public health problem. In this Commission, we examine several aspects of drug-resistant tuberculosis. The traditional view that acquired resistance to antituberculous drugs is driven by poor compliance and programmatic failure is now being questioned, and several lines of evidence suggest that alternative mechanisms-including pharmacokinetic variability, induction of efflux pumps that transport the drug out of cells, and suboptimal drug penetration into tuberculosis lesions-are likely crucial to the pathogenesis of drug-resistant tuberculosis. These factors have implications for the design of new interventions, drug delivery and dosing mechanisms, and public health policy. We discuss epidemiology and transmission dynamics, including new insights into the fundamental biology of transmission, and we review the utility of newer diagnostic tools, including

  13. Turning off the spigot: reducing drug-resistant tuberculosis transmission in resource-limited settings.

    PubMed

    Nardell, E; Dharmadhikari, A

    2010-10-01

    Ongoing transmission and re-infection, primarily in congregate settings, is a key factor fueling the global multidrug-resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB) epidemic, especially in association with the human immunodeficiency virus. Even as efforts to broadly implement conventional TB transmission control measures begin, current strategies may be incompletely effective under the overcrowded conditions extant in high-burden, resource-limited settings. Longstanding evidence suggesting that TB patients on effective therapy rapidly become non-infectious and that unsuspected, untreated TB cases account for the most transmission makes a strong case for the implementation of rapid point-of-care diagnostics coupled with fully supervised effective treatment. Among the most important decisions affecting transmission, the choice of an MDR-TB treatment model that includes community-based treatment may offer important advantages over hospital or clinic-based care, not only in cost and effectiveness, but also in transmission control. In the community, too, rapid identification of infectious cases, especially drug-resistant cases, followed by effective, fully supervised treatment, is critical to stopping transmission. Among the conventional interventions available, we present a simple triage and separation strategy, point out that separation is intimately linked to the design and engineering of clinical space and call attention to the pros and cons of natural ventilation, simple mechanical ventilation systems, germicidal ultraviolet air disinfection, fit-tested respirators on health care workers and short-term use of masks on patients before treatment is initiated.

  14. Turning off the spigot: reducing drug-resistant tuberculosis transmission in resource-limited settings

    PubMed Central

    Nardell, E.; Dharmadhikari, A.

    2013-01-01

    SUMMARY Ongoing transmission and re-infection, primarily in congregate settings, is a key factor fueling the global multidrug-resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB) epidemic, especially in association with the human immunodeficiency virus. Even as efforts to broadly implement conventional TB transmission control measures begin, current strategies may be incompletely effective under the overcrowded conditions extant in high-burden, resource-limited settings. Longstanding evidence suggesting that TB patients on effective therapy rapidly become non-infectious and that unsuspected, untreated TB cases account for the most transmission makes a strong case for the implementation of rapid point-of-care diagnostics coupled with fully supervised effective treatment. Among the most important decisions affecting transmission, the choice of an MDR-TB treatment model that includes community-based treatment may offer important advantages over hospital or clinic-based care, not only in cost and effectiveness, but also in transmission control. In the community, too, rapid identification of infectious cases, especially drug-resistant cases, followed by effective, fully supervised treatment, is critical to stopping transmission. Among the conventional interventions available, we present a simple triage and separation strategy, point out that separation is intimately linked to the design and engineering of clinical space and call attention to the pros and cons of natural ventilation, simple mechanical ventilation systems, germicidal ultraviolet air disinfection, fit-tested respirators on health care workers and short-term use of masks on patients before treatment is initiated. PMID:20843413

  15. 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.

  16. 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

  17. Transmission of multidrug-resistant and extensively drug-resistant tuberculosis in rural Bangladesh: lessons learnt.

    PubMed

    Gumusboga, A; Aung, K J M; Rigouts, L; Van Deun, A

    2012-09-21

    We report community transmission of multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) documented by fingerprinting, with secondary cases appearing over a period of 10 years. The index case failed MDR-TB treatment, with amplification to XDR-TB after refusing treatment when first diagnosed and developing pre-XDR-TB on private treatment. Some of the first MDR-TB patients were not started on appropriate treatment due to delayed diagnosis or to excessively rigid application of National TB Programme guidelines. Early presumptive MDR- and XDR-TB diagnosis and removal of barriers, such as obligatory hospitalisation, could have stopped this trend of resistance amplification and transmission.

  18. A train passenger with pulmonary tuberculosis: evidence of limited transmission during travel.

    PubMed

    Moore, M; Valway, S E; Ihle, W; Onorato, I M

    1999-01-01

    In January 1996, smear- and culture-positive tuberculosis (TB) was diagnosed for a 22-year-old black man after he had traveled on two U.S. passenger trains (29.1 hours) and a bus (5.5 hours) over 2 days. To determine if transmission had occurred, passengers and crew were notified of the potential exposure and instructed to undergo a tuberculin skin test (TST). Of the 240 persons who completed screening, 4 (2%) had a documented TST conversion (increase in induration of > or = 10 mm between successive TSTs), 11 (5%) had a single positive TST (> or = 10 mm), and 225 (94%) had a negative TST (< 10 mm). For two persons who underwent conversion, no other risk factors for a conversion were identified other than exposure to the ill passenger during train and/or bus travel. These findings support limited transmission of Mycobacterium tuberculosis from a potentially highly infectious passenger to other persons during extended train and bus travel.

  19. Analysis of changes in recent tuberculosis transmission patterns after a sharp increase in immigration.

    PubMed

    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.

  20. Acquisition of second-line drug resistance and extensive drug resistance during recent transmission of Mycobacterium tuberculosis in rural China.

    PubMed

    Hu, Y; Mathema, B; Zhao, Q; Chen, L; Lu, W; Wang, W; Kreiswirth, B; Xu, B

    2015-12-01

    Multidrug-resistant tuberculosis (MDR-TB) is prevalent in countries with a high TB burden, like China. As little is known about the emergence and spread of second-line drug (SLD) -resistant TB, we investigate the emergence and transmission of SLD-resistant Mycobacterium tuberculosis in rural China. In a multi-centre population-based study, we described the bacterial population structure and the transmission characteristics of SLD-resistant TB using Spoligotyping in combination with genotyping based on 24-locus MIRU-VNTR (mycobacterial interspersed repetitive unit-variable-number tandem repeat) plus four highly variable loci for the Beijing family, in four rural Chinese regions with diverse geographic and socio-demographic characteristics. Transmission networks among genotypically clustered patients were constructed using social network analysis. Of 1332 M. tuberculosis patient isolates recovered, the Beijing family represented 74.8% of all isolates and an association with MDR and simultaneous resistance between first-line drugs and SLDs. The genotyping analysis revealed that 189 isolates shared MIRU-VNTR patterns in 78 clusters with clustering rate and recent transmission rate of 14.2% and 8.3%, respectively. Fifty-three SLD-resistant isolates were observed in 31 clusters, 30 of which contained the strains with different drug susceptibility profiles and genetic mutations. In conjunction with molecular data, socio-network analysis indicated a key role of Central Township in the transmission across a highly interconnected network where SLD resistance accumulation occurred during transmission. SLD-resistant M. tuberculosis has been spreading in rural China with Beijing family being the dominant strains. Primary transmission of SLD-resistant strains in the population highlights the importance of routine drug susceptibility testing and effective anti-tuberculosis regimens for drug-resistant TB.

  1. 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.

  2. Genetic Diversity and Transmission Characteristics of Beijing Family Strains of Mycobacterium tuberculosis in Peru

    PubMed Central

    Iwamoto, Tomotada; Grandjean, Louis; Arikawa, Kentaro; Nakanishi, Noriko; Caviedes, Luz; Coronel, Jorge; Sheen, Patricia; Wada, Takayuki; Taype, Carmen A.; Shaw, Marie-Anne; Moore, David A. J.; Gilman, Robert H.

    2012-01-01

    Beijing family strains of Mycobacterium tuberculosis have attracted worldwide attention because of their wide geographical distribution and global emergence. Peru, which has a historical relationship with East Asia, is considered to be a hotspot for Beijing family strains in South America. We aimed to unveil the genetic diversity and transmission characteristics of the Beijing strains in Peru. A total of 200 Beijing family strains were identified from 2140 M. tuberculosis isolates obtained in Lima, Peru, between December 2008 and January 2010. Of them, 198 strains were classified into sublineages, on the basis of 10 sets of single nucleotide polymorphisms (SNPs). They were also subjected to variable number tandem-repeat (VNTR) typing using an international standard set of 15 loci (15-MIRU-VNTR) plus 9 additional loci optimized for Beijing strains. An additional 70 Beijing family strains, isolated between 1999 and 2006 in Lima, were also analyzed in order to make a longitudinal comparison. The Beijing family was the third largest spoligotyping clade in Peru. Its population structure, by SNP typing, was characterized by a high frequency of Sequence Type 10 (ST10), which belongs to a modern subfamily of Beijing strains (178/198, 89.9%). Twelve strains belonged to the ancient subfamily (ST3 [n = 3], ST25 [n = 1], ST19 [n = 8]). Overall, the polymorphic information content for each of the 24 loci values was low. The 24 loci VNTR showed a high clustering rate (80.3%) and a high recent transmission index (RTIn−1 = 0.707). These strongly suggest the active and on-going transmission of Beijing family strains in the survey area. Notably, 1 VNTR genotype was found to account for 43.9% of the strains. Comparisons with data from East Asia suggested the genotype emerged as a uniquely endemic clone in Peru. A longitudinal comparison revealed the genotype was present in Lima by 1999. PMID:23185395

  3. 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.

  4. Construction of a mathematical model for tuberculosis transmission in highly endemic regions of the Asia-Pacific.

    PubMed

    Trauer, James M; Denholm, Justin T; McBryde, Emma S

    2014-10-07

    We present a mathematical model to simulate tuberculosis (TB) transmission in highly endemic regions of the Asia-Pacific, where epidemiology does not appear to be primarily driven by HIV-coinfection. The ten-compartment deterministic model captures many of the observed phenomena important to disease dynamics, including partial and temporary vaccine efficacy, declining risk of active disease following infection, the possibility of reinfection both during the infection latent period and after treatment, multidrug resistant TB (MDR-TB) and de novo resistance during treatment. We found that the model could not be calibrated to the estimated incidence rate without allowing for reinfection during latency, and that even in the presence of a moderate fitness cost and a lower value of R0, MDR-TB becomes the dominant strain at equilibrium. Of the modifiable programmatic parameters, the rate of detection and treatment commencement was the most important determinant of disease rates with each respective strain, while vaccination rates were less important. Improved treatment of drug-susceptible TB did not result in decreased rates of MDR-TB through prevention of de novo resistance, but rather resulted in a modest increase in MDR-TB through strain replacement. This was due to the considerably greater relative contribution of community transmission to MDR-TB incidence, by comparison to de novo amplification of resistance in previously susceptible strains.

  5. Image-based spectral transmission estimation using "sensitivity comparison".

    PubMed

    Nahavandi, Alireza Mahmoudi; Tehran, Mohammad Amani

    2017-01-20

    Although digital cameras have been used for spectral reflectance estimation, transmission measurement has rarely been considered in studies. This study presents a method named sensitivity comparison (SC) for spectral transmission estimation. The method needs neither a priori knowledge from the samples nor statistical information of a given reflectance dataset. As with spectrophotometers, the SC method needs one shot for calibration and another shot for measurement. The method exploits the sensitivity of the camera in the absence and presence of transparent colored objects for transmission estimation. 138 Kodak Wratten Gelatin filter transmissions were used for controlling the proposed method. Using modeling of the imaging system in different levels of noise, the performance of the proposed method was compared with a training-based Matrix R method. For checking the performance of the SC method in practice, 33 manmade colored transparent films were used in a conventional three-channel camera. The method generated promising results using different error metrics.

  6. 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.

  7. Transmission of Mycobacterium tuberculosis from an Asian elephant (Elephas maximus) to a chimpanzee (Pan troglodytes) and humans in an Australian zoo.

    PubMed

    Stephens, N; Vogelnest, L; Lowbridge, C; Christensen, A; Marks, G B; Sintchenko, V; McAnulty, J

    2013-07-01

    Mycobacterium tuberculosis is primarily a pathogen of humans. Infections have been reported in animal species and it is emerging as a significant disease of elephants in the care of humans. With the close association between humans and animals, transmission can occur. In November 2010, a clinically healthy Asian elephant in an Australian zoo was found to be shedding M. tuberculosis; in September 2011, a sick chimpanzee at the same zoo was diagnosed with tuberculosis caused by an indistinguishable strain of M. tuberculosis. Investigations included staff and animal screening. Four staff had tuberculin skin test conversions associated with spending at least 10 hours within the elephant enclosure; none had disease. Six chimpanzees had suspected infection. A pathway of transmission between the animals could not be confirmed. Tuberculosis in an elephant can be transmissible to people in close contact and to other animals more remotely. The mechanism for transmission from elephants requires further investigation.

  8. 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.

  9. Population decline induced by gonorrhoea and tuberculosis transmission: Micronesia during the Japanese occupation, 1919-45.

    PubMed

    Cassels, Susan; Singer, Burton H

    2010-12-01

    The islands of Yap in Micronesia survived a period of severe depopulation during the Japanese occupation from 1919 to 1945. Using data from historical documents, supplemented by ethnographic evidence, we calibrate a simulation model that accounts for this phenomenon. Our model tracks the reproduction histories of a synthetic cohort of women in Yap, including effects of infertility due to gonorrhoea as well as tuberculosis mortality, and predicts the net reproduction rate (NRR). In this particular case and throughout history, human migrations and associated social and cultural interactions have frequently been accompanied by dramatic changes in patterns of disease transmission and substantial demographic consequences. Despite the broad emphasis on mortality as a measure of demographic consequences in the historical and contemporary literature, there are important instances where life expectancy at birth, fertility rates, and total population size are important demographic consequences. We find that gonorrhoea may have significantly contributed to depopulation during the Japanese occupation of Micronesia, due to repeated infections and high risk of sterility. Results of our model suggest that gonorrhoea alone could have reduced the net reproduction rate by 82%, whereas deaths from tuberculosis may have contributed to a 17% decline.

  10. Tuberculosis.

    PubMed

    Pearce, Lynne

    2017-03-10

    Essential facts Tuberculosis (TB) is an infection caused by a bacterium, mycobacterium tuberculosis. While it can affect any part of the body, only pulmonary TB is infectious. According to the charity TB Alert, there were 5,758 cases of TB in the UK in 2015 and 39% of them were in London. This represented a fall from a peak of 8,919 cases in 2011. Left untreated, TB is life-threatening, but is usually curable with antibiotics. The sooner it is diagnosed and treated, the better, both for the person's health and in preventing them from passing the infection on to others.

  11. Tuberculosis.

    PubMed

    Pearce, Lynne

    2017-02-22

    Essential facts Tuberculosis (TB) is an infection caused by a bacterium, mycobacterium tuberculosis. While it can affect any part of the body, only pulmonary TB is infectious. According to the charity TB Alert, there were 5,758 cases of TB in the UK in 2015 and 39% of them were in London. This represented a fall from a peak of 8,919 cases in 2011. Left untreated, TB is life-threatening, but is usually curable with antibiotics. The sooner it is diagnosed and treated, the better, both for the person's health and in preventing them from passing the infection on to others.

  12. Within the Enemy’s Camp: contribution of the granuloma to the dissemination, persistence and transmission of Mycobacterium tuberculosis

    PubMed Central

    Shaler, Christopher R.; Horvath, Carly N.; Jeyanathan, Mangalakumari; Xing, Zhou

    2013-01-01

    Pulmonary tuberculosis, caused by Mycobacterium tuberculosis (M.tb) represents a leading global health concern, with 8.7 million newly emerging cases, and 1.4 million reported deaths annually. Despite an estimated one third of the world’s population being infected, relatively few infected individuals ever develop active clinical disease. The ability of the host to remain latently infected while preventing disease is thought to be due to the generation of a robust type 1 immune response in the lung, capable of controlling, but not clearing, M.tb. A key feature of the type 1 immune response to M.tb is the formation of immune cellular aggregates termed granuloma. The granuloma structure has long been considered a hallmark of host’s protective response toward M.tb. Historically, a correlative relationship between granuloma formation/maintenance and bacterial control has been seen in models where disrupted granuloma formation or structure was found to be fatal. Despite this established relationship much about the granuloma’s role in M.tb immunity remains unknown. Recent publications suggest that the granuloma actually aids the persistence of M.tb and that the development of a necrotic granuloma is essential to person-to-person transmission. Our group and others have recently demonstrated that enclosed within the granuloma is a population of immunologically altered antigen-presenting cells and T lymphocyte populations. Of note, the ability of these populations to produce type 1 cytokines such as interferon-gamma, and bactericidal products including nitric oxide, are significantly reduced, while remaining competent to produce high levels immunosuppressive interleukin-10. These observations indicate that although the chronic granuloma represents a highly unique environment, it is more similar to that of a tumor than an active site of bacterial control. In this review we will explore what is known about this unique environment and its contribution to the persistence

  13. 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

  14. Evaluating parasite densities and estimation of parameters in transmission systems.

    PubMed

    Heinzmann, D; Torgerson, P R

    2008-09-01

    Mathematical modelling of parasite transmission systems can provide useful information about host parasite interactions and biology and parasite population dynamics. In addition good predictive models may assist in designing control programmes to reduce the burden of human and animal disease. Model building is only the first part of the process. These models then need to be confronted with data to obtain parameter estimates and the accuracy of these estimates has to be evaluated. Estimation of parasite densities is central to this. Parasite density estimates can include the proportion of hosts infected with parasites (prevalence) or estimates of the parasite biomass within the host population (abundance or intensity estimates). Parasite density estimation is often complicated by highly aggregated distributions of parasites within the hosts. This causes additional challenges when calculating transmission parameters. Using Echinococcus spp. as a model organism, this manuscript gives a brief overview of the types of descriptors of parasite densities, how to estimate them and on the use of these estimates in a transmission model.

  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. Estimating regional transmissivity of the Upper Floridan aquifer

    SciTech Connect

    Johnston, R.H. )

    1993-03-01

    The distribution of permeability in the Upper Floridan aquifer is complex due to variations in the original depositional environments and the post-depositional history. The transmissivity of the aquifer is directly related to the thickness and lithology of the overlying confining unit (Miocene clastic deposits). Where this unit has been thinned or removed by erosion, solution-cavity development and thus high transmissivity are common. At depth, transmissivity is affected by the lithology of the carbonate rocks and the occurrence of paleokarst. The transmissivity of the Upper Floridan varies by more than three orders of magnitude: from less than 1,000 feet squared per day in the thickly confined, micrite-rich limestone of the Fort Walton Beach area of panhandle Florida to more than 1,000,000 feet squared per day in the unconfined, karstic areas of central and northern Florida. The application of aquifer-test methods to determine transmissivity of the Upper Floridan aquifer is summarized as follows: (1) Conducting aquifer tests in the unconfined, karstic areas is virtually impossible because of logistical problems (removing large volumes of pumped water to prevent recycling) and because non-Darcian flow can preclude the use of standard aquifer-test methods. However, flow-net analyses using springs as the discharge control have been used successfully to estimate regional transmissivity values. (2) Multi-well aquifer tests outside of karst areas generally provide data plots that match appropriate type curves. (3) Specific capacity is not a good basis for estimating regional transmissivity values. Transmissivity maps of the Floridan should be accompanied by an evaluation of their reliability based on availability of field-test data. If transmissivity values are derived from computer models, the model sensitivity to transmissivity should be discussed.

  17. COUNTING THE MISSING CASES: ESTIMATING THE GLOBAL BURDEN OF MULTIDRUG-RESISTANT TUBERCULOSIS AMONG PREVALENT CASES OF TB

    PubMed Central

    Nourzad, Susan; Jenkins, Helen E.; Milstein, Meredith; Mitnick, Carole D.

    2017-01-01

    SUMMARY Background Multidrug-resistant tuberculosis (MDR-TB) burden estimates are based on incomplete, infrequently updated data among a limited pool of cases: notified or incident, pulmonary TB patients. Methods Using WHO data reported by 217 countries/territories in 2014, we calculated MDR-TB burdens among prevalent TB cases and compared these with estimates among incident and notified TB patients. We also compared treatment coverage across estimates. Findings Among prevalent TB patients globally in 2014, we estimate that 555,545 (95% credible bounds: 499,340–617,391) MDR-TB cases occurred. This is 85% more than the 300,000 estimated among notified cases, and 16% more than the 480,000 among incident cases. Only 20% of MDR-TB cases among prevalent—compared to 37% of MDR-TB among notified—TB patients had access to MDR-TB treatment. Applying prior estimates, only 10% of MDR-TB cases will have successful outcomes. Interpretation Estimates based on likely-to-be-diagnosed cases of MDR-TB overlook a significant proportion of morbidity, mortality, and transmission: that occur in undiagnosed, untreated, prevalent TB patients. Still likely underestimating the true disease burden, MDR-TB among patients with prevalent TB represents a closer approximation of disease burden than currently reported indicators. Progress toward elimination—or control—depends on policies guided by a more complete representation of the disease burden. PMID:28157458

  18. A Model of Tuberculosis Transmission and Intervention Strategies in an Urban Residential Area

    PubMed Central

    Pienaar, Elsje; Fluitt, Aaron M.; Whitney, Scott E.; Freifeld, Alison G.; Viljoen, Hendrik J.

    2011-01-01

    The model herein aims to explore the dynamics of the spread of tuberculosis (TB) in an informal settlement or township. The population is divided into households of various sizes and also based on commuting status. The model dynamics distinguishes between three distinct social patterns: the exposure of commuters during travel, random diurnal interaction and familial exposure at night. Following the general SLIR models, the population is further segmented into susceptible (S), exposed/latently infected (L), active/infectious (I), and recovered (R) individuals. During the daytime, commuters travel on public transport, while non-commuters randomly interact in the community to mimic chance encounters with infectious persons. At night, each family interacts and sleeps together in the home. The risk of exposure to TB is based on the proximity, duration, and frequency of encounters with infectious persons. The model is applied to a hypothetical population to explore the effects of different intervention strategies including vaccination, wearing of masks or scarves during the commute, prophylactic treatment of latent infections and more effective case-finding and treatment. The most important findings of the model are: (1) members of larger families are responsible for more disease transmissions than those from smaller families, (2) daily commutes on public transport provide ideal conditions for transmission of the disease, (3) improved diagnosis and treatment has the greatest impact on the spread of the disease, and (4) detecting TB at the first clinic visit, when patients are still smear negative, is key. PMID:20381428

  19. Preventing the Transmission of Tuberculosis in Health Care Settings: Administrative Control

    PubMed Central

    2017-01-01

    It is well established that health care workers (HCWs) have a considerably higher risk of occupationally acquired tuberculosis (TB). To reduce the transmission of TB to HCWs and patients, TB infection control programs should be implemented in health care settings. The first and most important level of all protection and control programs is administrative control. Its goals are to prevent HCWs, other staff, and patients from being exposed to TB, and to reduce the transmission of infection by ensuring rapid diagnosis and treatment of affected individuals. Administrative control measures recommended by the United States Centers for Disease Control and Prevention and the World Health Organization include prompt identification of people with TB symptoms, isolation of infectious patients, control of the spread of the pathogen, and minimization of time spent in health care facilities. Another key component of measures undertaken is the baseline and serial screening for latent TB infection in HCWs who are at risk of exposure to TB. Although the interferon-gamma release assay has some advantages over the tuberculin skin test, the former has serious limitations, mostly due to its high conversion rate. PMID:28119743

  20. Tuberculosis.

    PubMed

    Jacobson, Karen R

    2017-02-07

    This issue provides a clinical overview of tuberculosis, focusing on screening, prevention, diagnosis, and treatment. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  1. 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.

  2. Estimation of multiple transmission rates for epidemics in heterogeneous populations.

    PubMed

    Cook, Alex R; Otten, Wilfred; Marion, Glenn; Gibson, Gavin J; Gilligan, Christopher A

    2007-12-18

    One of the principal challenges in epidemiological modeling is to parameterize models with realistic estimates for transmission rates in order to analyze strategies for control and to predict disease outcomes. Using a combination of replicated experiments, Bayesian statistical inference, and stochastic modeling, we introduce and illustrate a strategy to estimate transmission parameters for the spread of infection through a two-phase mosaic, comprising favorable and unfavorable hosts. We focus on epidemics with local dispersal and formulate a spatially explicit, stochastic set of transition probabilities using a percolation paradigm for a susceptible-infected (S-I) epidemiological model. The S-I percolation model is further generalized to allow for multiple sources of infection including external inoculum and host-to-host infection. We fit the model using Bayesian inference and Markov chain Monte Carlo simulation to successive snapshots of damping-off disease spreading through replicated plant populations that differ in relative proportions of favorable and unfavorable hosts and with time-varying rates of transmission. Epidemiologically plausible parametric forms for these transmission rates are compared by using the deviance information criterion. Our results show that there are four transmission rates for a two-phase system, corresponding to each combination of infected donor and susceptible recipient. Knowing the number and magnitudes of the transmission rates allows the dominant pathways for transmission in a heterogeneous population to be identified. Finally, we show how failure to allow for multiple transmission rates can overestimate or underestimate the rate of spread of epidemics in heterogeneous environments, which could lead to marked failure or inefficiency of control strategies.

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

    PubMed Central

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

    1997-01-01

    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. 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

  5. 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.

  6. Networked Estimation with an Area-Triggered Transmission Method

    PubMed Central

    Nguyen, Vinh Hao; Suh, Young Soo

    2008-01-01

    This paper is concerned with the networked estimation problem in which sensor data are transmitted over the network. In the event-driven sampling scheme known as level-crossing or send-on-delta, sensor data are transmitted to the estimator node if the difference between the current sensor value and the last transmitted one is greater than a given threshold. The event-driven sampling generally requires less transmission than the time-driven one. However, the transmission rate of the send-on-delta method becomes large when the sensor noise is large since sensor data variation becomes large due to the sensor noise. Motivated by this issue, we propose another event-driven sampling method called area-triggered in which sensor data are sent only when the integral of differences between the current sensor value and the last transmitted one is greater than a given threshold. Through theoretical analysis and simulation results, we show that in the certain cases the proposed method not only reduces data transmission rate but also improves estimation performance in comparison with the conventional event-driven method. PMID:27879742

  7. 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

  8. Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

    PubMed Central

    Escombe, A. Roderick; Moore, David A. J; Gilman, Robert H; Navincopa, Marcos; Ticona, Eduardo; Mitchell, Bailey; Noakes, Catherine; Martínez, Carlos; Sheen, Patricia; Ramirez, Rocio; Quino, Willi; Gonzalez, Armando; Friedland, Jon S; Evans, Carlton A

    2009-01-01

    Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of

  9. 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.

  10. Use of cattle farm resources by badgers (Meles meles) and risk of bovine tuberculosis (Mycobacterium bovis) transmission to cattle.

    PubMed

    Garnett, B T; Delahay, R J; Roper, T J

    2002-07-22

    Nocturnal observations, radio telemetry and time-lapse camera surveillance were used to investigate visits by badgers (Meles meles L.) to two cattle farms. During 59 half-nights (ca. 295 h) of observation and 17 nights (ca. 154 h) of camera surveillance, 139 separate visits to farm buildings, by at least 26 individually identifiable badgers from two social groups, were recorded. The badgers, which included three individuals infected with bovine tuberculosis (Mycobacterium bovis), used cowsheds, feedsheds, barns, haystacks, slurry pits, cattle troughs and farmyards to exploit a range of food resources, including cattle feed and silage. Cattle feed was contaminated with badger faeces and badgers also came into close contact with cattle. The minimum number of badgers visiting farm buildings per night was negatively correlated with local 24 h rainfall. We conclude that exploitation by badgers of resources provided by cattle farms constitutes a potentially important mechanism for tuberculosis transmission from badgers to cattle.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. INCIDENCE OF MULTIDRUG-RESISTANT TUBERCULOSIS DISEASE IN CHILDREN: SYSTEMATIC REVIEW AND GLOBAL ESTIMATES

    PubMed Central

    Jenkins, Helen E.; Tolman, Arielle W.; Yuen, Courtney M.; Parr, Jonathan B.; Keshavjee, Salmaan; Pérez-Vélez, Carlos M.; Pagano, Marcello; Becerra, Mercedes C.; Cohen, Ted

    2014-01-01

    Background Multidrug-resistant tuberculosis (MDR-TB) threatens to reverse recent reductions in global tuberculosis (TB) incidence. Although children under 15 years of age constitute >25% of the worldwide population, the global incidence of MDR-TB disease in children has never been quantified. Methods Our approach for estimating regional and global annual incidence of MDR-TB in children required development of two models: one to estimate the setting-specific risk of MDR-TB among child TB cases, and a second to estimate the setting-specific incidence of TB disease in children. The model for MDR-TB risk among children with TB required a systematic literature review. We multiplied the setting-specific estimates of MDR-TB risk and TB incidence to estimate regional and global incidence of MDR-TB disease in children in 2010. Findings We identified 3,403 papers, of which 97 studies met inclusion criteria for the systematic review of MDR-TB risk. Thirty-one studies reported the risk of MDR-TB among both children and treatment-naïve adults with TB and were used for evaluating the linear association between MDR-TB risk in these two patient groups. We found that the setting-specific risk of MDR-TB was nearly identical in children and treatment-naïve adults with TB, consistent with the assertion that MDR-TB in both groups reflects the local risk of transmitted MDR-TB. Applying these calculated risks, we estimated that around 1,000,000 (95% Confidence Interval: 938,000 – 1,055,000) children developed TB disease in 2010, among whom 32,000 (95% Confidence Interval: 26,000 – 39,000) had MDR-TB. Interpretation Our estimates highlight a massive detection gap for children with TB and MDR-TB disease. Future estimates can be refined as more and better TB data and new diagnostic tools become available. PMID:24671080

  16. Interpretation of transmissivity estimates from single-well pumping aquifer tests

    USGS Publications Warehouse

    Halford, K.J.; Weight, W.D.; Schreiber, R.P.

    2006-01-01

    Interpretation of single-well tests with the Cooper-Jacob method remains more reasonable than most alternatives. Drawdowns from 628 simulated single-well tests where transmissivity was specified were interpreted with the Cooper-Jacob straight-line method to estimate transmissivity. Error and bias as a function of vertical anisotropy, partial penetration, specific yield, and interpretive technique were investigated for transmissivities that ranged from 10 to 10,000 m2/d. Cooper-Jacob transmissivity estimates in confined aquifers were affected minimally by partial penetration, vertical anisotropy, or analyst. Cooper-Jacob transmissivity estimates of simulated unconfined aquifers averaged twice the known values. Transmissivity estimates of unconfined aquifers were not improved by interpreting results with an unconfined aquifer solution. Judicious interpretation of late-time data consistently improved estimates where transmissivity exceeded 250 m2/d in unconfined aquifers. ?? 2006 National Ground Water Association.

  17. 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

  18. Growth and cell-division in extensive (XDR) and extremely drug resistant (XXDR) tuberculosis strains: transmission and atomic force observation.

    PubMed

    Farnia, Parissa; Mohammad, Reza Masjedi; Merza, Muayad Aghali; Tabarsi, Payam; Zhavnerko, Gennadii Konstantinovich; Ibrahim, Tengku Azmi; Kuan, Ho Oi; Ghanavei, Jalladein; Farnia, Poopak; Ranjbar, Reza; Poleschuyk, Nikolai Nikolaevich; Titov, Leonid Petrovich; Owlia, Parviz; Kazampour, Mehadi; Setareh, Mohammad; Sheikolslami, Muaryam; Migliori, Giovanni Battista; Velayati, Ali Akbar

    2010-09-30

    The ultra-structure of Mycobacterium tuberculosis (MTB) was examined by transmission electronic (TEM)) and atomic force microscopy (AFM). The study was performed to describe the morphology of susceptible, multidrug-resistant (MDR), extensively drug-resistant (XDR) and extremely drug-resistant tuberculosis isolates (XXDR-TB) during their exponential growth phase. Four types of cell division were observed and described. While three of them (symmetrical, asymmetrical and branching type) occurred in all isolates studied, the fourth one (adapted type) was seen only in XDR and XXDR-TB bacilli. In the fourth type of cell division, a rod shaped mother cell produced a small round shape bacillus (0.3-0.5 μm). These round cells were different from buds or polar division, but similar to terminal endospores without showing the typing heat resistance. Based on the present observation, we suggest that XDR-and XXDR-TB bacilli accommodate changes helping them to overcome the hostile environment. Viewed under AFM, the other frequently detected shapes in MTB isolates were oval, V, Y and multi-branching filaments. These shape variation confirmed pleomorphic phenomena in MTB populations and the specific features of pan-resistant strains.

  19. Evolutionary History and Ongoing Transmission of Phylogenetic Sublineages of Mycobacterium tuberculosis Beijing Genotype in China

    PubMed Central

    Yin, Qing-qin; Liu, Hai-can; Jiao, Wei-wei; Li, Qin-jing; Han, Rui; Tian, Jian-ling; Liu, Zhi-guang; Zhao, Xiu-qin; Li, Ying-jia; Wan, Kang-lin; Shen, A-dong; Mokrousov, Igor

    2016-01-01

    Mycobacterium tuberculosis Beijing genotype originated in China and has undergone a dramatic population growth and global spread in the last century. Here, a collection of M. tuberculosis Beijing family isolates from different provinces across all China was genotyped by high-resolution (24-MIRU-VNTR) and low-resolution, high-rank (modern and ancient sublineages) markers. The molecular profiles and global and local phylogenies were compared to the strain phenotype and patient data. The phylogeographic patterns observed in the studied collection demonstrate that large-scale (but not middle/small-scale) distance remains one of the decisive factors of the genetic divergence of M. tuberculosis populations. Analysis of diversity and network topology of the local collections appears to corroborate a recent intriguing hypothesis about Beijing genotype originating in South China. Placing our results within the Eurasian context suggested that important Russian B0/W148 and Asian/Russian A0/94-32 epidemic clones of the Beijing genotype could trace their origins to the northeastern and northwestern regions of China, respectively. The higher clustering of the modern isolates in children and lack of increased MDR rate in any sublineage suggest that not association with drug resistance but other (e.g., speculatively, virulence-related) properties underlie an enhanced dissemination of the evolutionarily recent, modern sublineage of the Beijing genotype in China. PMID:27681182

  20. Trial design to estimate the effect of vaccination on tuberculosis incidence in badgers.

    PubMed

    Aznar, Inma; McGrath, Guy; Murphy, Denise; Corner, Leigh A L; Gormley, Eamonn; Frankena, Klaas; More, Simon J; Martin, Wayne; O'Keeffe, James; De Jong, Mart C M

    2011-07-05

    The principal wildlife reservoir of Mycobacterium bovis in Ireland is the European badger. Studies in the Republic of Ireland (RoI) have shown that badgers culled in association with cattle herd tuberculosis breakdowns (focal culling) have a higher prevalence of infection than the badger population at large. This observation is one rationale for the medium term national strategy of focal badger culling. A vaccination strategy for the control of bovine tuberculosis (bTB) in badgers is a preferred long-term option. The Bacillus Calmette-Guérin (BCG) vaccine has been shown to decrease disease severity in captive badgers under controlled conditions. As the vaccine has been tested in a controlled environment with precise information on infection pressure, it cannot be assumed a priori that the effects of vaccination are similar in the wild, where other environmental and/or ecological factors prevail. For this reason we have designed a vaccine field trial to assess the impact of vaccination on the incidence of TB infection in a wild badger population. The selected study area for the vaccine trial (approximately 755 square kilometers) is divided into three zones each of which has similar characteristics in terms of size, number of main badger setts, cattle herds, cattle and land classification type. Three vaccination levels (100%, 50% and 0%) will be allocated to the three zones in a way that a gradient of vaccination coverage North to South is achieved. The middle zone (zone B) will be vaccinated at a 50% coverage but zone A and C will be randomly allocated with 100% or 0% vaccination coverage. Vaccination within zone B will be done randomly at individual badger level. The objective of this paper is to describe the design of a field tuberculosis vaccination trial for badgers, the epidemiological methods that were used to design the trial and the subsequent data analysis. The analysis will enable us to quantify the magnitude of the observed vaccination effect on M. bovis

  1. The impact of migrant workers on the tuberculosis transmission: general models and a case study for China.

    PubMed

    Liu, Luju; Wu, Jianhong; Zhao, Xiao-Qiang

    2012-10-01

    A tuberculosis (TB) transmission model involving migrant workers is proposed and investigated. The basic reproduction number R0 is calculated, and is shown to be a threshold parameter for the disease to persist or become extinct in the population. The existence and global attractivity of an endemic equilibrium, if R0 > 1, is also established under some technical conditions. A case study, based on the TB epidemiological and other statistical data in China, indicates that the disease spread can be controlled if effective measures are taken to reduce the reactivation rate of exposed/latent migrant workers. Impact of the migration rate and direction, as well as the duration of home visit stay, on the control of disease spread is also examined numerically.

  2. 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

  3. Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA.

    PubMed

    Lavelle, Michael J; Kay, Shannon L; Pepin, Kim M; Grear, Daniel A; Campa, Henry; VerCauteren, Kurt C

    2016-12-01

    Direct and indirect contacts among individuals drive transmission of infectious disease. When multiple interacting species are susceptible to the same pathogen, risk assessment must include all potential host species. Bovine tuberculosis (bTB) is an example of a disease that can be transmitted among several wildlife species and to cattle, although the potential role of several wildlife species in spillback to cattle remains unclear. To better understand the complex network of contacts and factors driving disease transmission, we fitted proximity logger collars to beef and dairy cattle (n=37), white-tailed deer (Odocoileus virginianus; n=29), raccoon (Procyon lotor; n=53), and Virginia opossum (Didelphis virginiana; n=79) for 16 months in Michigan's Lower Peninsula, USA. We determined inter- and intra-species direct and indirect contact rates. Data on indirect contact was calculated when collared animals visited stationary proximity loggers placed at cattle feed and water resources. Most contact between wildlife species and cattle was indirect, with the highest contact rates occurring between raccoons and cattle during summer and fall. Nearly all visits (>99%) to cattle feed and water sources were by cattle, whereas visitation to stored cattle feed was dominated by deer and raccoon (46% and 38%, respectively). Our results suggest that indirect contact resulting from wildlife species visiting cattle-related resources could pose a risk of disease transmission to cattle and deserves continued attention with active mitigation.

  4. 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.

  5. Challenges in Obtaining Estimates of the Risk of Tuberculosis Infection during Overseas Deployment

    PubMed Central

    Mancuso, James D.; Geurts, Mia

    2015-01-01

    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

  6. The Global Burden of Latent Tuberculosis Infection: A Re-estimation Using Mathematical Modelling

    PubMed Central

    Houben, Rein M. G. J.

    2016-01-01

    methodological heterogeneity of direct ARI data, and limited evidence to inform on potential clearance of LTBI. Conclusions We estimate that approximately 1.7 billion individuals were latently infected with Mycobacterium tuberculosis (M.tb) globally in 2014, just under a quarter of the global population. Investment in new tools to improve diagnosis and treatment of those with LTBI at risk of progressing to disease is urgently needed to address this latent reservoir if the 2050 target of eliminating TB is to be reached. PMID:27780211

  7. 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

  8. Tuberculosis Infection and Latent Tuberculosis

    PubMed Central

    2016-01-01

    Active tuberculosis (TB) has a greater burden of TB bacilli than latent TB and acts as an infection source for contacts. Latent tuberculosis infection (LTBI) is the state in which humans are infected with Mycobacterium tuberculosis without any clinical symptoms, radiological abnormality, or microbiological evidence. TB is transmissible by respiratory droplet nucleus of 1–5 µm in diameter, containing 1–10 TB bacilli. TB transmission is affected by the strength of the infectious source, infectiousness of TB bacilli, immunoresistance of the host, environmental stresses, and biosocial factors. Infection controls to reduce TB transmission consist of managerial activities, administrative control, engineering control, environmental control, and personal protective equipment provision. However, diagnosis and treatment for LTBI as a national TB control program is an important strategy on the precondition that active TB is not missed. Therefore, more concrete evidences for LTBI management based on clinical and public perspectives are needed. PMID:27790271

  9. 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

    2015-10-06

    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.

  10. 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

  11. The perfect storm: incarceration and the high-risk environment perpetuating transmission of HIV, hepatitis C virus, and tuberculosis in Eastern Europe and Central Asia.

    PubMed

    Altice, Frederick L; Azbel, Lyuba; Stone, Jack; Brooks-Pollock, Ellen; Smyrnov, Pavlo; Dvoriak, Sergii; Taxman, Faye S; El-Bassel, Nabila; Martin, Natasha K; Booth, Robert; Stöver, Heino; Dolan, Kate; Vickerman, Peter

    2016-09-17

    Despite global reductions in HIV incidence and mortality, the 15 UNAIDS-designated countries of Eastern Europe and Central Asia (EECA) that gained independence from the Soviet Union in 1991 constitute the only region where both continue to rise. HIV transmission in EECA is fuelled primarily by injection of opioids, with harsh criminalisation of drug use that has resulted in extraordinarily high levels of incarceration. Consequently, people who inject drugs, including those with HIV, hepatitis C virus, and tuberculosis, are concentrated within prisons. Evidence-based primary and secondary prevention of HIV using opioid agonist therapies such as methadone and buprenorphine is available in prisons in only a handful of EECA countries (methadone or buprenorphine in five countries and needle and syringe programmes in three countries), with none of them meeting recommended coverage levels. Similarly, antiretroviral therapy coverage, especially among people who inject drugs, is markedly under-scaled. Russia completely bans opioid agonist therapies and does not support needle and syringe programmes-with neither available in prisons-despite the country's high incarceration rate and having the largest burden of people with HIV who inject drugs in the region. Mathematical modelling for Ukraine suggests that high levels of incarceration in EECA countries facilitate HIV transmission among people who inject drugs, with 28-55% of all new HIV infections over the next 15 years predicted to be attributable to heightened HIV transmission risk among currently or previously incarcerated people who inject drugs. Scaling up of opioid agonist therapies within prisons and maintaining treatment after release would yield the greatest HIV transmission reduction in people who inject drugs. Additional analyses also suggest that at least 6% of all incident tuberculosis cases, and 75% of incident tuberculosis cases in people who inject drugs are due to incarceration. Interventions that reduce

  12. Efficient Acoustic Uncertainty Estimation for Transmission Loss Calculations

    DTIC Science & Technology

    2011-09-01

    Soc. Am. Vol. 129, 589-592. PUBLICATIONS [1] Kundu , P.K., Cohen, I.M., and Dowling, D.R., Fluid Mechanics , 5th Ed. (Academic Press, Oxford, 2012), 891 pages. ...Transmission Loss Calculations Kevin R. James Department of Mechanical Engineering University of Michigan Ann Arbor, MI 48109-2133 phone: (734) 998...1807 fax: (734) 764-4256 email: krj@umich.edu David R. Dowling Department of Mechanical Engineering University of Michigan Ann Arbor, MI

  13. Cryogenic transmission electron microscopy of recombinant tuberculosis vaccine antigen with anionic liposomes reveals formation of flattened liposomes.

    PubMed

    Fox, Christopher B; Mulligan, Sean K; Sung, Joyce; Dowling, Quinton M; Fung, H W Millie; Vedvick, Thomas S; Coler, Rhea N

    2014-01-01

    Development of lipid-based adjuvant formulations to enhance the immunogenicity of recombinant vaccine antigens is a focus of modern vaccine research. Characterizing interactions between vaccine antigens and formulation excipients is important for establishing compatibility between the different components and optimizing vaccine stability and potency. Cryogenic transmission electron microscopy (TEM) is a highly informative analytical technique that may elucidate various aspects of protein- and lipid-based structures, including morphology, size, shape, and phase structure, while avoiding artifacts associated with staining-based TEM. In this work, cryogenic TEM is employed to characterize a recombinant tuberculosis vaccine antigen, an anionic liposome formulation, and antigen-liposome interactions. By performing three-dimensional tomographic reconstruction analysis, the formation of a population of protein-containing flattened liposomes, not present in the control samples, was detected. It is shown that cryogenic TEM provides unique information regarding antigen-liposome interactions not detectable by light-scattering-based methods. Employing a suite of complementary analytical techniques is important to fully characterize interactions between vaccine components.

  14. Gender differentials of pulmonary tuberculosis transmission and reactivation in an endemic area

    PubMed Central

    Jiménez‐Corona, M‐E; García‐García, L; DeRiemer, K; Ferreyra‐Reyes, L; Bobadilla‐del‐Valle, M; Cano‐Arellano, B; Canizales‐Quintero, S; Martínez‐Gamboa, A; Small, P M; Sifuentes‐Osornio, J; Ponce‐de‐León, A

    2006-01-01

    Background In most low income countries there are twice as many cases of tuberculosis (TB) reported among men than among women, a difference commonly attributed to biological and epidemiological characteristics as well as socioeconomic and cultural barriers in access to health care. The World Health Organization has encouraged gender specific comparisons in TB rates to determine whether women with TB are less likely than men with TB to be diagnosed, reported, and treated. A study was undertaken to identify gender based differences in patients with pulmonary TB and to use this information to improve TB control efforts. Methods Individuals with a cough for more than 2 weeks in southern Mexico were screened from March 1995 to April 2003. Clinical and mycobacteriological information (isolation, identification, drug susceptibility testing and IS6110 based genotyping, and spoligotyping) was collected from those with bacteriologically confirmed pulmonary TB. Patients were treated in accordance with official norms and followed to ascertain treatment outcome, retreatment, and vital status. Results 623 patients with pulmonary TB were enrolled. The male:female incidence rate ratio for overall, reactivated, and recently transmitted disease was 1.58 (95% CI 1.34 to 1.86), 1.64 (95% CI 1.36 to 1.98), and 1.41 (95% CI 1.01 to 1.96), respectively. Men were more likely than women to default from treatment (adjusted OR 3.30, 95% CI 1.46 to 7.43), to be retreated (hazard ratio (HR) 3.15, 95% CI 1.38 to 7.22), and to die from TB (HR 2.23, 95% CI 1.25 to 3.99). Conclusions Higher rates of transmitted and reactivated disease and poorer treatment outcomes among men are indicators of gender differentials in the diagnosis and treatment of pulmonary TB, and suggest specific strategies in endemic settings. PMID:16449260

  15. Identifiability and estimation of multiple transmission pathways in cholera and waterborne disease.

    PubMed

    Eisenberg, Marisa C; Robertson, Suzanne L; Tien, Joseph H

    2013-05-07

    Cholera and many waterborne diseases exhibit multiple characteristic timescales or pathways of infection, which can be modeled as direct and indirect transmission. A major public health issue for waterborne diseases involves understanding the modes of transmission in order to improve control and prevention strategies. An important epidemiological question is: given data for an outbreak, can we determine the role and relative importance of direct vs. environmental/waterborne routes of transmission? We examine whether parameters for a differential equation model of waterborne disease transmission dynamics can be identified, both in the ideal setting of noise-free data (structural identifiability) and in the more realistic setting in the presence of noise (practical identifiability). We used a differential algebra approach together with several numerical approaches, with a particular emphasis on identifiability of the transmission rates. To examine these issues in a practical public health context, we apply the model to a recent cholera outbreak in Angola (2006). Our results show that the model parameters-including both water and person-to-person transmission routes-are globally structurally identifiable, although they become unidentifiable when the environmental transmission timescale is fast. Even for water dynamics within the identifiable range, when noisy data are considered, only a combination of the water transmission parameters can practically be estimated. This makes the waterborne transmission parameters difficult to estimate, leading to inaccurate estimates of important epidemiological parameters such as the basic reproduction number (R0). However, measurements of pathogen persistence time in environmental water sources or measurements of pathogen concentration in the water can improve model identifiability and allow for more accurate estimation of waterborne transmission pathway parameters as well as R0. Parameter estimates for the Angola outbreak suggest

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. The evolution of tuberculosis virulence.

    PubMed

    Basu, Sanjay; Galvani, Alison P

    2009-07-01

    The evolution of Mycobacterium tuberculosis presents several challenges for public health. HIV and resistance to antimycobacterial medications have evolutionary implications for how Mycobacterium tuberculosis will evolve, as these factors influence the host environment and transmission dynamics of tuberculosis strains. We present an evolutionary invasion analysis of tuberculosis that characterizes the direction of tuberculosis evolution in the context of different natural and human-driven selective pressures, including changes in tuberculosis treatment and HIV prevalence. We find that the evolution of tuberculosis virulence can be affected by treatment success rates, the relative transmissibility of emerging strains, the rate of reactivation from latency among hosts, and the life expectancy of hosts. We find that the virulence of tuberculosis strains may also increase as a consequence of rising HIV prevalence, requiring faster case detection strategies in areas where the epidemics of HIV and tuberculosis collide.

  1. 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

  2. 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

  3. 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.

  4. The perfect storm: incarceration and the high-risk environment perpetuating transmission of HIV, hepatitis C virus, and tuberculosis in Eastern Europe and Central Asia

    PubMed Central

    Altice, Frederick L; Azbel, Lyuba; Stone, Jack; Brooks-Pollock, Ellen; Smyrnov, Pavlo; Dvoriak, Sergii; Taxman, Faye S; El-Bassel, Nabila; Martin, Natasha K; Booth, Robert; Stöver, Heino; Dolan, Kate; Vickerman, Peter

    2016-01-01

    Despite global reductions in HIV incidence and mortality, the 15 UNAIDS-designated countries of Eastern Europe and Central Asia (EECA) that gained independence from the Soviet Union in 1991 constitute the only region where both continue to rise. HIV transmission in EECA is fuelled primarily by injection of opioids, with harsh criminalisation of drug use that has resulted in extraordinarily high levels of incarceration. Consequently, people who inject drugs, including those with HIV, hepatitis C virus, and tuberculosis, are concentrated within prisons. Evidence-based primary and secondary prevention of HIV using opioid agonist therapies such as methadone and buprenorphine is available in prisons in only a handful of EECA countries (methadone or buprenorphine in five countries and needle and syringe programmes in three countries), with none of them meeting recommended coverage levels. Similarly, antiretroviral therapy coverage, especially among people who inject drugs, is markedly under-scaled. Russia completely bans opioid agonist therapies and does not support needle and syringe programmes—with neither available in prisons—despite the country’s high incarceration rate and having the largest burden of people with HIV who inject drugs in the region. Mathematical modelling for Ukraine suggests that high levels of incarceration in EECA countries facilitate HIV transmission among people who inject drugs, with 28–55% of all new HIV infections over the next 15 years predicted to be attributable to heightened HIV transmission risk among currently or previously incarcerated people who inject drugs. Scaling up of opioid agonist therapies within prisons and maintaining treatment after release would yield the greatest HIV transmission reduction in people who inject drugs. Additional analyses also suggest that at least 6% of all incident tuberculosis cases, and 75% of incident tuberculosis cases in people who inject drugs are due to incarceration. Interventions that

  5. Bayesian Approach for the Estimation of the Transmissivity Spatial Structure from Hydraulic Tomography Data

    NASA Astrophysics Data System (ADS)

    Demir, M. T.; Copty, N. K.; Trinchero, P.; Sanchez-Vila, X.

    2013-12-01

    Groundwater flow and contaminant transport are strongly influenced by the spatial variability of subsurface flow parameters. However, the interpretation of pumping test data used for subsurface characterization is normally performed using conventional methods that are based on the assumption of aquifer homogeneity. In recent years, hydraulic tomography has been proposed by some researchers to address the limitations of conventional site characterization methods. Hydraulic tomography involves the sequential pumping at one of a series of wells and observing the drawdown due to pumping at adjacent wells. The interpretation of the drawdown data from hydraulic tomography has been mostly performed using formal inverse procedures for the estimation of the spatial variability of the flow parameters. The purpose of this study is to develop a method for the estimation of the statistical spatial structure of the transmissivity from hydraulic tomography data. The method relies on the pumping test interpretation procedure of Copty et al. (2011), which uses the time-drawdown data and its time derivative at each observation well to estimate the spatially averaged transmissivity as a function of radial distance from the pumping well. A Bayesian approach is then used to identify the statistical parameters of the transmissivity field (i.e. variance and integral scale). The approach compares the estimated transmissivity as a function of radial distance from the pumping well to the probability density function of the spatially-averaged transmissivity. The method is evaluated using synthetically-generated pumping test data for a range of input parameters. This application demonstrates that, through a relatively simple procedure, additional information of the spatial structure of the transmissivity may be inferred from pumping tests data. Results indicate that as the number of available pumping tests increases, the reliability of the estimated transmissivity statistical parameters also

  6. 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

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

    PubMed

    2013-10-04

    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.

  9. Estimation of the transmission of foot-and-mouth disease virus from infected sheep to cattle

    PubMed Central

    2014-01-01

    The quantitative role of sheep in the transmission of foot-and-mouth disease virus (FMDV) is not well known. To estimate the role of sheep in the transmission of FMDV, a direct contact transmission experiment with 10 groups of animals each consisting of 2 infected lambs and 1 contact calf was performed. Secretions and excretions (oral swabs, blood, urine, faeces and probang samples) from all animals were tested for the presence of FMDV by virus isolation (VI) and/or RT-PCR. Serum was tested for the presence of antibodies against FMDV. To estimate FMDV transmission, the VI, RT-PCR and serology results were used. The partial reproduction ratio R0p i.e. the average number of new infections caused by one infected sheep introduced into a population of susceptible cattle, was estimated using either data of the whole infection chain of the experimental epidemics (the transient state method) or the final sizes of the experimental epidemics (the final size method). Using the transient state method, R0p was estimated as 1.0 (95% CI 0.2 - 6.0) using virus isolation results and 1.4 (95% CI 0.3 - 8.0) using RT-PCR results. Using the final size method, R0p was estimated as 0.9 (95% CI 0.2 - 3.0). Finally, R0p was compared to the R0’s obtained in previous transmission studies with sheep or cattle only. This comparison showed that the infectivity of sheep is lower than that of cattle and that sheep and cattle are similarly susceptible to FMD. These results indicate that in a mixed population of sheep and cattle, sheep play a more limited role in the transmission of FMDV than cattle. PMID:24886222

  10. Testing branching process estimators of cascading failure with data from a simulation of transmission line outages.

    PubMed

    Dobson, Ian; Kim, Janghoon; Wierzbicki, Kevin R

    2010-04-01

    We suggest a statistical estimator to quantify the propagation of cascading transmission line failures in large blackouts of electric power systems. We use a Galton-Watson branching process model of cascading failure and the standard Harris estimator of the mean propagation modified to work when the process saturates at a maximum number of components. If the mean number of initial failures and the mean propagation are estimated, then the branching process model predicts the distribution of the total number of failures. We initially test this prediction on failure data generated by a simulation of cascading transmission line outages on two standard test systems. We discuss the effectiveness of the estimator in terms of how many cascades need to be simulated to predict the distribution of the total number of line outages accurately.

  11. 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.

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

    PubMed Central

    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

  13. Stochastic BER estimation for coherent QPSK transmission systems with digital carrier phase recovery.

    PubMed

    Zhang, Fan; Gao, Yan; Luo, Yazhi; Chen, Zhangyuan; Xu, Anshi

    2010-04-26

    We propose a stochastic bit error ratio estimation approach based on a statistical analysis of the retrieved signal phase for coherent optical QPSK systems with digital carrier phase recovery. A family of the generalized exponential function is applied to fit the probability density function of the signal samples. The method provides reasonable performance estimation in presence of both linear and nonlinear transmission impairments while reduces the computational intensity greatly compared to Monte Carlo simulation.

  14. 77 FR 16126 - Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for Mycobacterium tuberculosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-19

    ... and control materials with the possibility of transmission of tuberculosis infection to healthcare... materials with the possibility of transmission of tuberculosis infection to healthcare workers could be... of rapid detection of infection in patients with suspected tuberculosis as compared to...

  15. Location estimation of an in vivo robotic capsule relative to arrayed power transmission coils.

    PubMed

    Kim, Jong Dae; Ryu, Munho; Hwang, Ji Soo; Kim, Jongwon

    2008-06-01

    A tracking method is presented here for an in vivo robotic capsule with power supplied from one of the multiple power transmission coils. The proposed method aims to select the best coupled coil among the array of power transmission coils. It relies on the fact that the driving current of the power transmitter increases with inductive coupling of the receiver coil inside the capsule with the transmitter coil. Investigation of the current increase characteristic according to its location relative to the transmission coils allows development of a strategy for the in vivo robotic capsule. This study shows results with two transmission coils and a two-dimensional power receiver. Experimental results present the possibility of selecting the best coil by estimating the relative location of the capsule.

  16. 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.

  17. 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.

  18. 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.

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

    PubMed

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

    2012-02-07

    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.

  20. Estimating infectious disease transmission distances using the overall distribution of cases.

    PubMed

    Salje, Henrik; Cummings, Derek A T; Lessler, Justin

    2016-12-01

    The average spatial distance between transmission-linked cases is a fundamental property of infectious disease dispersal. However, the distance between a case and their infector is rarely measurable. Contact-tracing investigations are resource intensive or even impossible, particularly when only a subset of cases are detected. Here, we developed an approach that uses onset dates, the generation time distribution and location information to estimate the mean transmission distance. We tested our method using outbreak simulations. We then applied it to the 2001 foot-and-mouth outbreak in Cumbria, UK, and compared our results to contact-tracing activities. In simulations with a true mean distance of 106m, the average mean distance estimated was 109m when cases were fully observed (95% range of 71-142). Estimates remained consistent with the true mean distance when only five percent of cases were observed, (average estimate of 128m, 95% range 87-165). Estimates were robust to spatial heterogeneity in the underlying population. We estimated that both the mean and the standard deviation of the transmission distance during the 2001 foot-and-mouth outbreak was 8.9km (95% CI: 8.4km-9.7km). Contact-tracing activities found similar values of 6.3km (5.2km-7.4km) and 11.2km (9.5km-12.8km), respectively. We were also able to capture the drop in mean transmission distance over the course of the outbreak. Our approach is applicable across diseases, robust to under-reporting and can inform interventions and surveillance.

  1. 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.

  2. Prevalence of previously undetected tuberculosis and underlying risk factors for transmission in a prison setting in Ibadan, south-western Nigeria

    PubMed Central

    Adesokan, HK; Cadmus, EO; Adeyemi, WB; Lawal, O.; Ogunlade, C.O.; Osman, E.; Olaleye, OD; Cadmus, SIB

    2014-01-01

    Summary People with congregational tendencies such as the prison inmates constitute an important target group in the global efforts towards the control of tuberculosis (TB). The prison setting in most developing countries particularly Nigeria, currently does not have routine diagnostic procedures for TB despite the existing risks that could facilitate disease transmission. We conducted a cross sectional study among the inmates in a major prison in south-western Nigeria for TB by screening their sputum samples using a simple random sampling method coupled with questionnaire interview, on the assumption of sub-clinical pulmonary TB infection. The overall TB prevalence found was 1.2% (2/164). Significant risk factors that could facilitate disease transmission in the prison included lack of BCG immunization (p = 0.017); history of contact with TB patients (p = 0.020); prolonged cough (p = 0.016) and drug abuse (p = 0.019). Our findings of 1.2% undetected pulmonary TB infection among the inmates though low; still reiterate previous observation that the prison setting constitutes a veritable environment for TB transmission and a threat to public health. Efforts are therefore needed to institute routine screening and reduce the risk factors associated with TB transmission among prison inmates in Nigeria. PMID:26689165

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

    PubMed

    Blumberg, S; Lloyd-Smith, J O

    2013-09-01

    Many diseases exhibit subcritical transmission (i.e. 0transmission 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 models used

  4. Tuberculosis (TB)

    MedlinePlus

    ... with facebook share with twitter share with linkedin Tuberculosis (TB) Tuberculosis (TB) is a contagious and often ... are drug resistant. Why Is the Study of Tuberculosis (TB) a Priority for NIAID? Tuberculosis is one ...

  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%.

  7. 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.

  8. 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.

  9. 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

  10. Block Transmissions over Doubly Selective Channels: Iterative Channel Estimation and Turbo Equalization

    NASA Astrophysics Data System (ADS)

    Fang, Kun; Rugini, Luca; Leus, Geert

    2010-12-01

    Modern wireless communication systems require high transmission rates, giving rise to frequency selectivity due to multipath propagation. In addition, high-mobility terminals and scatterers induce Doppler shifts that introduce time selectivity. Therefore, advanced techniques are needed to accurately model the time- and frequency-selective (i.e., doubly selective) channels and to counteract the related performance degradation. In this paper, we develop new receivers for orthogonal frequency-division multiplexing (OFDM) systems and single-carrier (SC) systems in doubly selective channels by embedding the channel estimation task within low-complexity block turbo equalizers. Linear minimum mean-squared error (MMSE) pilot-assisted channel estimators are presented, and the soft data estimates from the turbo equalizers are used to improve the quality of the channel estimates.

  11. 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.

  12. 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.

  13. Determining the Risk of Intra-Community Transmission of Tuberculosis in the Northwest of Iran Through 15 Loci Miru-Vntr Typing

    PubMed Central

    Afaghi-Gharamaleki, Ali; Moaddab, Seyyedreza; Darbouy, Mojtaba; Ansarin, Khalil; Hanifian, Shahram

    2017-01-01

    This study was carried out in order to investigating the effect of travelling on the transmission of tuberculosis from high- to low-burden TB countries. Mycobacteria samples isolated from patients of distinct and relatively co-related countries (Azerbaijan Republic and Tabriz [located in the northwest of Iran]) were analyzed through 15 loci MIRU-VNTR typing method. PCR was done using special primers for each of the loci; then the number of allele repeats for all loci were determined by the size of their fragments. Finally, the created numeric patterns for each isolate were analyzed and clustered, using MIRU-VNTRplus.org website. All 119 isolates dispersing at 106 distinct patterns were composed of 10 clusters with 23 members and 96 unique patterns. Nine and five loci had high and moderate discriminatory power, respectively, but only one of them was poor in clustering. The study showed that 89.08% of TB cases involved resulted from the reactivation pattern and 10.92% were related to ongoing transmission. Although Azerbaijan Republic is a higher-burden TB region than Tabriz and Azerbaijan people make frequent tours to Tabriz to receive low or free medical services, the findings showed no TB transmission from the regions at least during the year of the study. PMID:28386470

  14. Parameter estimation and simulations of a mathematical model of Corynebacterium pseudotuberculosis transmission in sheep.

    PubMed

    O'Reilly, K M; Green, L E; Malone, F E; Medley, G F

    2008-03-17

    Caseous lymphadenitis (CLA) is an infectious disease of sheep caused by Corynebacterium pseudotuberculosis. It is prevalent in most sheep producing countries and was introduced into the UK sheep population in 1991. The pathogen invades the host through epithelium and forms an abscess in the local draining lymph node. Typically, disease presents as clinical, with overt (externally visible) swollen lymph nodes (the parotid, submandibular, prefemoral, prescapular, popliteal or mammary) or sub-clinical, with abscesses in the lungs and associated thoracic (bronchial and mediastinal) lymph nodes. We present a mathematical model in which disease is categorised as overt and/or respiratory (sub-clinical), using the above groupings. In both situations sheep may be infected and may or may not be infectious. In the model, overt abscesses may resolve and respiratory abscesses are considered to be present for life. Using the location of the abscesses, three routes of transmission are postulated: overt to overt, respiratory to overt and respiratory to respiratory. Data from four naturally infected flocks were used to describe populations of sheep with epidemic CLA and to estimate transmission coefficients for each of the postulated transmission routes. The infection process parameters were derived from literature where possible. Parameters were estimated using maximum likelihood methods and compared to the data using a multinomial distribution. The distribution of abscesses in the flocks was similar to endemic data reported in other studies. In the model most infected sheep developed abscesses, and approximately 36% of sheep with overt abscesses recovered from infection. The average time for respiratory abscesses to become infectious was 41 days. In these data, overt to overt transmission was the most frequent route of transmission since it had the highest coefficient in the model compared with respiratory to overt and respiratory to respiratory transmission. Transmission

  15. Predominant Mycobacterium tuberculosis Families and High Rates of Recent Transmission among New Cases Are Not Associated with Primary Multidrug Resistance in Lima, Peru.

    PubMed

    Barletta, Francesca; Otero, Larissa; de Jong, Bouke C; Iwamoto, Tomotada; Arikawa, Kentaro; Van der Stuyft, Patrick; Niemann, Stefan; Merker, Matthias; Uwizeye, Cécile; Seas, Carlos; Rigouts, Leen

    2015-06-01

    Sputum samples from new tuberculosis (TB) cases were collected over 2 years as part of a prospective study in the northeastern part of Lima, Peru. To measure the contribution of recent transmission to the high rates of multidrug resistance (MDR) in this area, Mycobacterium tuberculosis complex (MTBc) isolates were tested for drug susceptibility to first-line drugs and were genotyped by spoligotyping and 15-locus mycobacterial interspersed repetitive-unit (MIRU-15)-variable-number tandem repeat (VNTR) analysis. MDR was found in 6.8% of 844 isolates, of which 593 (70.3%) were identified as belonging to a known MTBc lineage, whereas 198 isolates (23.5%) could not be assigned to these lineages and 12 (1.4%) represented mixed infections. Lineage 4 accounted for 54.9% (n = 463) of the isolates, most of which belonged to the Haarlem family (n = 279). MIRU-15 analysis grouped 551/791 isolates (69.7%) in 102 clusters, with sizes ranging from 2 to 46 strains. The overall high clustering rate suggests a high level of recent transmission in this population, especially among younger patients (odds ratio [OR], 1.6; P = 0.01). Haarlem strains were more prone to cluster, compared to the other families taken together (OR, 2.0; P < 0.0001), while Beijing (OR, 0.6; P = 0.006) and LAM (OR, 0.7; P = 0.07) strains clustered less. Whereas streptomycin-resistant strains were more commonly found in clusters (OR, 1.8; P = 0.03), clustering rates did not differ between MDR and non-MDR strains (OR, 1.8; P = 0.1). Furthermore, only 16/51 MDR strains clustered with other MDR strains, suggesting that patients with primary MDR infections acquired the infections mostly from index cases outside the study population, such as retreated cases.

  16. Improving Estimation Performance in Networked Control Systems Applying the Send-on-delta Transmission Method

    PubMed Central

    Nguyen, Vinh Hao; Suh, Young Soo

    2007-01-01

    This paper is concerned with improving performance of a state estimation problem over a network in which a send-on-delta (SOD) transmission method is used. The SOD method requires that a sensor node transmit data to the estimator node only if its measurement value changes more than a given specified δ value. This method has been explored and applied by researchers because of its efficiency in the network bandwidth improvement. However, when this method is used, it is not ensured that the estimator node receives data from the sensor nodes regularly at every estimation period. Therefore, we propose a method to reduce estimation error in case of no sensor data reception. When the estimator node does not receive data from the sensor node, the sensor value is known to be in a (−δi,+δi) interval from the last transmitted sensor value. This implicit information has been used to improve estimation performance in previous studies. The main contribution of this paper is to propose an algorithm, where the sensor value interval is reduced to (−δi/2,+δi/2) in certain situations. Thus, the proposed algorithm improves the overall estimation performance without any changes in the send-on-delta algorithms of the sensor nodes. Through numerical simulations, we demonstrate the feasibility and the usefulness of the proposed method.

  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. Rapid Test for Identification of a Highly Transmissible Mycobacterium tuberculosis Beijing Strain of Sub-Saharan Origin

    PubMed Central

    Alonso, Henar; Gavín, Patricia; Hernández-Febles, Melissa; Campos-Herrero, María Isolina; Copado, Rodolfo; Cañas, Fernando; Kremer, Kristin; Caminero, José Antonio; Martín, Carlos; Samper, Sofía

    2012-01-01

    The development of a rapid test to identify Mycobacterium tuberculosis Beijing isolates and specifically strain GC1237, coming from a sub-Saharan country, is needed due to its alarming wide spread on Gran Canaria Island (Spain). A rapid test that detects IS6110 present between dnaA and dnaN in the Beijing strains and in a specific site for GC1237 (Rv2180c) has been developed. This test would be a useful tool in the surveillance of subsequent cases. PMID:22116140

  19. Towards Risk-Based Test Protocols: Estimating the Contribution of Intensive Testing to the UK Bovine Tuberculosis Problem

    PubMed Central

    van Dijk, Jan

    2013-01-01

    Eradicating disease from livestock populations involves the balancing act of removing sufficient numbers of diseased animals without removing too many healthy individuals in the process. As ever more tests for bovine tuberculosis (BTB) are carried out on the UK cattle herd, and each positive herd test triggers more testing, the question arises whether ‘false positive’ results contribute significantly to the measured BTB prevalence. Here, this question is explored using simple probabilistic models of test behaviour. When the screening test is applied to the average UK herd, the estimated proportion of test-associated false positive new outbreaks is highly sensitive to small fluctuations in screening test specificity. Estimations of this parameter should be updated as a priority. Once outbreaks have been confirmed in screening-test positive herds, the following rounds of intensive testing with more sensitive, albeit less specific, tests are highly likely to remove large numbers of false positive animals from herds. Despite this, it is unlikely that significantly more truly infected animals are removed. BTB test protocols should become based on quantified risk in order to prevent the needless slaughter of large numbers of healthy animals. PMID:23717517

  20. 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

  1. Geostatistics and Bayesian updating for transmissivity estimation in a multiaquifer system in Manitoba, Canada.

    PubMed

    Kennedy, Paula L; Woodbury, Allan D

    2002-01-01

    In ground water flow and transport modeling, the heterogeneous nature of porous media has a considerable effect on the resulting flow and solute transport. Some method of generating the heterogeneous field from a limited dataset of uncertain measurements is required. Bayesian updating is one method that interpolates from an uncertain dataset using the statistics of the underlying probability distribution function. In this paper, Bayesian updating was used to determine the heterogeneous natural log transmissivity field for a carbonate and a sandstone aquifer in southern Manitoba. It was determined that the transmissivity in m2/sec followed a natural log normal distribution for both aquifers with a mean of -7.2 and - 8.0 for the carbonate and sandstone aquifers, respectively. The variograms were calculated using an estimator developed by Li and Lake (1994). Fractal nature was not evident in the variogram from either aquifer. The Bayesian updating heterogeneous field provided good results even in cases where little data was available. A large transmissivity zone in the sandstone aquifer was created by the Bayesian procedure, which is not a reflection of any deterministic consideration, but is a natural outcome of updating a prior probability distribution function with observations. The statistical model returns a result that is very reasonable; that is homogeneous in regions where little or no information is available to alter an initial state. No long range correlation trends or fractal behavior of the log-transmissivity field was observed in either aquifer over a distance of about 300 km.

  2. 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

  3. 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

    2016-07-08

    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.

  4. 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.

  5. Estimating magnetic fields of homes near transmission lines in the California Power Line Study.

    PubMed

    Vergara, Ximena P; Kavet, Robert; Crespi, Catherine M; Hooper, Chris; Silva, J Michael; Kheifets, Leeka

    2015-07-01

    The California Power Line Study is a case-control study investigating the relation between residences near transmission lines and risk of childhood leukemia. It includes 5788 childhood leukemia cases and 5788 matched primary controls born between 1986 and 2007. We describe the methodology for estimating magnetic fields at study residences as well as for characterizing sources of uncertainty in these estimates. Birth residences of study subjects were geocoded and their distances to transmission lines were ascertained. 302 residences were deemed sufficiently close to transmission lines to have non-zero magnetic fields attributable to the lines. These residences were visited and detailed data, describing the physical configuration and dimensions of the lines contributing to the magnetic field at the residence, were collected. Phasing, loading, and directional load flow data for years of birth and diagnosis for each subject as well as for the day of site visit were obtained from utilities when available; when yearly average load for a particular year was not available, extrapolated values based on expert knowledge and prediction models were obtained. These data were used to estimate the magnetic fields at the center, closest and farthest point of each residence. We found good correlation between calculated fields and spot measurements of fields taken on site during visits. Our modeling strategies yielded similar calculated field estimates, and they were in high agreement with utility extrapolations. Phasing was known for over 90% of the lines. Important sources of uncertainty included a lack of information on the precise location of residences located within apartment buildings or other complexes. Our findings suggest that we were able to achieve high specificity in exposure assessment, which is essential for examining the association between distance to or magnetic fields from power lines and childhood leukemia risk.

  6. Implication of the RD(Rio) Mycobacterium tuberculosis sublineage in multidrug resistant tuberculosis in Portugal.

    PubMed

    David, Susana; Duarte, Elsa L; Leite, Clarice Queico Fugimura; Ribeiro, João-Nuno; Maio, José-Nuno; Paixão, Eleonora; Portugal, Clara; Sancho, Luísa; Germano de Sousa, José

    2012-10-01

    Multidrug and extensively drug resistant Mycobacterium tuberculosis are a threat to tuberculosis control programs. Genotyping methods, such as spoligotyping and MIRU-VNTR typing (Mycobacterial Interspersed Repetitive Units), are useful in monitoring potentially epidemic strains and estimating strain phylogenetic lineages and/or genotypic families. M. tuberculosis Latin American Mediterranean (LAM) family is a major worldwide contributor to tuberculosis (TB). LAM specific molecular markers, Ag85C(103) single nucleotide polymorphism (SNP) and RD(Rio) long-sequence polymorphism (LSP), were used to characterize spoligotype signatures from 859 patient isolates from Portugal. LAM strains were found responsible for 57.7% of all tuberculosis cases. Strains with the RD(Rio) deletion (referred to as RD(Rio)) were estimated to represent 1/3 of all the strains and over 60% of the multidrug resistant (MDR) strains. The major spoligotype signature SIT20 belonging to the LAM1 RD(Rio) sublineage, represented close to 1/5th of all the strains, over 20% of which were MDR. Analysis of published datasets according to stipulated 12loci MIRU-VNTR RD(Rio) signatures revealed that 96.3% (129/134) of MDR and extensively drug resistant (XDR) clusters were RD(Rio). This is the first report associating the LAM RD(Rio) sublineage with MDR. These results are an important contribution to the monitoring of these strains with heightened transmission for future endeavors to arrest MDR-TB and XDR-TB.

  7. 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

  8. 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.

  9. Accurate and efficient velocity estimation using Transmission matrix formalism based on the domain decomposition method

    NASA Astrophysics Data System (ADS)

    Wang, Benfeng; Jakobsen, Morten; Wu, Ru-Shan; Lu, Wenkai; Chen, Xiaohong

    2017-03-01

    Full waveform inversion (FWI) has been regarded as an effective tool to build the velocity model for the following pre-stack depth migration. Traditional inversion methods are built on Born approximation and are initial model dependent, while this problem can be avoided by introducing Transmission matrix (T-matrix), because the T-matrix includes all orders of scattering effects. The T-matrix can be estimated from the spatial aperture and frequency bandwidth limited seismic data using linear optimization methods. However the full T-matrix inversion method (FTIM) is always required in order to estimate velocity perturbations, which is very time consuming. The efficiency can be improved using the previously proposed inverse thin-slab propagator (ITSP) method, especially for large scale models. However, the ITSP method is currently designed for smooth media, therefore the estimation results are unsatisfactory when the velocity perturbation is relatively large. In this paper, we propose a domain decomposition method (DDM) to improve the efficiency of the velocity estimation for models with large perturbations, as well as guarantee the estimation accuracy. Numerical examples for smooth Gaussian ball models and a reservoir model with sharp boundaries are performed using the ITSP method, the proposed DDM and the FTIM. The estimated velocity distributions, the relative errors and the elapsed time all demonstrate the validity of the proposed DDM.

  10. Control strategies for wildlife tuberculosis in Ireland.

    PubMed

    Gormley, E; Corner, L A L

    2013-11-01

    The principal domestic maintenance host for Mycobacterium bovis is infected cattle. In countries where comprehensive surveillance schemes have been applied, tuberculosis rarely affects an animal to the extent that it presents with clinical disease. In the latter stages of an eradication campaign, the aim is to maintain the disease-free status of clear herds and eliminate foci of infection in herds as well as restricting movement of infected animals from these herds, other than to slaughter. However, the eradication of tuberculosis from cattle herds may be compromised if infected wildlife species, such as Eurasian badgers (Meles meles), share the same environment and contribute to transmission of infection. The options for dealing with tuberculosis in the wildlife reservoir hosts are limited to segregation of domestic animals from the wildlife, culling of the wildlife host or vaccination. Options are further limited by conservation and social reasons, particularly where culling is concerned. In Ireland and the UK, vaccination of badgers against M. bovis, if successfully employed, could directly facilitate the completion of bovine tuberculosis eradication. Programmes of research into vaccination of badgers are being undertaken in both countries, and there is clear evidence that vaccination induces protection. Vaccine trials in captive badgers have established that the M. bovis bacille Calmette-Guérin (BCG) vaccine can induce a protective response that limits the distribution and severity of tuberculosis disease following experimental challenge. In Ireland, a large-scale field trial of oral BCG vaccination is being conducted to measure the protection generated in wild badgers subjected to natural transmission of infection and to estimate vaccine efficacy. The results will provide a framework for the development and implementation of a national strategy to address the disease in badger populations and if successful will remove this major impediment to tuberculosis

  11. Transmissivity and storage coefficient estimates from slug tests, Naval Air Warfare Center, West Trenton, New Jersey

    USGS Publications Warehouse

    Fiore, Alex R.

    2014-01-01

    Slug tests were conducted on 56 observation wells open to bedrock at the former Naval Air Warfare Center (NAWC) in West Trenton, New Jersey. Aquifer transmissivity (T) and storage coefficient (S) values for most wells were estimated from slug-test data using the Cooper-Bredehoeft-Papadopulos method. Test data from three wells exhibited fast, underdamped water-level responses and were analyzed with the Butler high-K method. The range of T at NAWC was approximately 0.07 to 10,000 square feet per day. At 11 wells, water levels did not change measurably after 20 minutes following slug insertion; transmissivity at these 11 wells was estimated to be less than 0.07 square feet per day. The range of S was approximately 10-10 to 0.01, the mode being 10-10. Water-level responses for tests at three wells fit poorly to the type curves of both methods, indicating that these methods were not appropriate for adequately estimating T and S from those data.

  12. 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

  13. Molecular Epidemiology of Mycobacterium tuberculosis among South African Gold Miners

    PubMed Central

    Lewis, James J.; Connors, Jeremy; Chihota, Violet N.; Shashkina, Elena; van der Meulen, Minty; Graviss, Edward A.; Ha, Ngan P.; Kreiswirth, Barry N.; Grant, Alison D.; Fielding, Katherine L.; Dorman, Susan E.; Churchyard, Gavin J.

    2015-01-01

    Rationale: HIV-associated tuberculosis remains a major health problem among the gold-mining workforce in South Africa. We postulate that high levels of recent transmission, indicated by strain clustering, are fueling the tuberculosis epidemic among gold miners. Objectives: To combine molecular and epidemiologic data to describe Mycobacterium tuberculosis genetic diversity, estimate levels of transmission, and examine risk factors for clustering. Methods: We conducted a cross-sectional study of culture-positive M. tuberculosis isolates in 15 gold mine shafts across three provinces in South Africa. All isolates were subject IS6110-based restriction fragment length polymorphisms, and we performed spoligotyping analysis and combined it with basic demographic and clinical information. Measurements and Main Results: Of the 1,602 M. tuberculosis patient isolates, 1,240 (78%) had genotyping data available for analysis. A highly diverse bacillary population was identified, comprising a total of 730 discrete genotypes. Four genotypic families (Latin American Mediterranean spoligotype family; W-Beijing; AH or X; and T1–T4) accounted for over 50% of all strains. Overall, 45% (560/1,240) of strains were genotypically clustered. The minimum estimate for recent transmission (n − 1 method) was 32% (range, 27–34%). There were no individual-level risk factors for clustering, apart from borderline evidence for being non–South African and having self-reported HIV infection. Conclusions: The high M. tuberculosis genetic diversity and lack of risk factors for clustering are indicative of a universal risk for disease among gold miners and likely mixing with nonmining populations. Our results underscore the urgent need to intensify interventions to interrupt transmission across the entire gold-mining workforce in South Africa. PMID:25419914

  14. 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

  15. Key transmission parameters of an institutional outbreak during the 1918 influenza pandemic estimated by mathematical modelling

    PubMed Central

    Sertsou, Gabriel; Wilson, Nick; Baker, Michael; Nelson, Peter; Roberts, Mick G

    2006-01-01

    Aim To estimate the key transmission parameters associated with an outbreak of pandemic influenza in an institutional setting (New Zealand 1918). Methods Historical morbidity and mortality data were obtained from the report of the medical officer for a large military camp. A susceptible-exposed-infectious-recovered epidemiological model was solved numerically to find a range of best-fit estimates for key epidemic parameters and an incidence curve. Mortality data were subsequently modelled by performing a convolution of incidence distribution with a best-fit incidence-mortality lag distribution. Results Basic reproduction number (R0) values for three possible scenarios ranged between 1.3, and 3.1, and corresponding average latent period and infectious period estimates ranged between 0.7 and 1.3 days, and 0.2 and 0.3 days respectively. The mean and median best-estimate incidence-mortality lag periods were 6.9 and 6.6 days respectively. This delay is consistent with secondary bacterial pneumonia being a relatively important cause of death in this predominantly young male population. Conclusion These R0 estimates are broadly consistent with others made for the 1918 influenza pandemic and are not particularly large relative to some other infectious diseases. This finding suggests that if a novel influenza strain of similar virulence emerged then it could potentially be controlled through the prompt use of major public health measures. PMID:17137517

  16. Estimating enhanced prevaccination measles transmission hotspots in the context of cross-scale dynamics

    PubMed Central

    Becker, Alexander D.; Birger, Ruthie B.; Teillant, Aude; Gastanaduy, Paul A.; Wallace, Gregory S.; Grenfell, Bryan T.

    2016-01-01

    A key question in clarifying human–environment interactions is how dynamic complexity develops across integrative scales from molecular to population and global levels. Apart from its public health importance, measles is an excellent test bed for such an analysis. Simple mechanistic models have successfully illuminated measles dynamics at the city and country levels, revealing seasonal forcing of transmission as a major driver of long-term epidemic behavior. Seasonal forcing ties closely to patterns of school aggregation at the individual and community levels, but there are few explicit estimates of school transmission due to the relative lack of epidemic data at this scale. Here, we use data from a 1904 measles outbreak in schools in Woolwich, London, coupled with a stochastic Susceptible-Infected-Recovered model to analyze measles incidence data. Our results indicate that transmission within schools and age classes is higher than previous population-level serological data would suggest. This analysis sheds quantitative light on the role of school-aged children in measles cross-scale dynamics, as we illustrate with references to the contemporary vaccination landscape. PMID:27872300

  17. Tracheobronchial tuberculosis

    PubMed Central

    Pathak, Vikas; Shepherd, Ray W.

    2016-01-01

    Tracheobronchial tuberculosis (TBTB) is reported in approximately 10% to 39% of the patients with pulmonary tuberculosis. It is defined as the tubercle infection of the trachea and or bronchi. Due to its non-specific presentation, insidious onset and normal chest radiography in about 10–20% of the patients, the diagnosis is delayed. Bronchoscopy is the most definite method of diagnosis which provides adequate specimens for microbiological and histopathological diagnosis. Tracheobronchial stenosis is one of the most common long term complications of TBTB resulting in significant morbidity. It is estimated that 90% of patients with TBTB have some degree of tracheal and or bronchial stenosis. In this review article, we will discuss the pathogenesis, symptoms, imaging, bronchoscopic findings, and treatment of TBTB and management of tracheobronchial stenosis. PMID:28149582

  18. Population estimation and trappability of the European badger (Meles meles): implications for tuberculosis management.

    PubMed

    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 km(2)) 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.

  19. 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

  20. Estimating uncertainty in subsurface glider position using transmissions from fixed acoustic tomography sources.

    PubMed

    Van Uffelen, Lora J; Nosal, Eva-Marie; Howe, Bruce M; Carter, Glenn S; Worcester, Peter F; Dzieciuch, Matthew A; Heaney, Kevin D; Campbell, Richard L; Cross, Patrick S

    2013-10-01

    Four acoustic Seagliders were deployed in the Philippine Sea November 2010 to April 2011 in the vicinity of an acoustic tomography array. The gliders recorded over 2000 broadband transmissions at ranges up to 700 km from moored acoustic sources as they transited between mooring sites. The precision of glider positioning at the time of acoustic reception is important to resolve the fundamental ambiguity between position and sound speed. The Seagliders utilized GPS at the surface and a kinematic model below for positioning. The gliders were typically underwater for about 6.4 h, diving to depths of 1000 m and traveling on average 3.6 km during a dive. Measured acoustic arrival peaks were unambiguously associated with predicted ray arrivals. Statistics of travel-time offsets between received arrivals and acoustic predictions were used to estimate range uncertainty. Range (travel time) uncertainty between the source and the glider position from the kinematic model is estimated to be 639 m (426 ms) rms. Least-squares solutions for glider position estimated from acoustically derived ranges from 5 sources differed by 914 m rms from modeled positions, with estimated uncertainty of 106 m rms in horizontal position. Error analysis included 70 ms rms of uncertainty due to oceanic sound-speed variability.

  1. Transmission

    SciTech Connect

    Sugano, K.

    1988-12-27

    A transmission is described which consists of: an input shaft; an output shaft; a first planetary gear set including a first sun gear selectively connectable by a first clutch to the input shaft, a first carrier selectively connectable by a second clutch to the input shaft and a first ring gear connected to the output shaft. The first sun gear selectively held stationary by a first brake, the first carrier is allowed to rotate in the same forward direction as the input shaft when the second clutch is engaged, but prevented from rotating in a reverse direction opposite to the forward direction by a first one-way clutch, the first carrier being selectively held stationary by a second brake; a second planetary gear set including a second sun gear connected to the input shaft, a second carrier connected to the first ring gear and also the the output shaft, and a second ring gear.

  2. 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

  3. Whole-Genome Sequences of Mycobacterium tuberculosis TB282 and TB284, a Widespread and a Unique Strain, Respectively, Identified in a Previous Study of Tuberculosis Transmission in Central Los Angeles, California, USA

    PubMed Central

    Yang, Zhenhua

    2017-01-01

    ABSTRACT We report here the genome sequences of two Mycobacterium tuberculosis clinical isolates previously identified in central Los Angeles, CA, in the 1990s using a PacBio platform. Isolate TB282 represents a large-cluster strain that caused 27% of the tuberculosis cases, while TB284 represents a strain that caused disease in only one patient. PMID:28082486

  4. Optimal estimation of spatially variable recharge and transmissivity fields under steady-state groundwater flow. Part 1. Theory

    NASA Astrophysics Data System (ADS)

    Graham, Wendy D.; Tankersley, Claude D.

    1994-05-01

    Stochastic methods are used to analyze two-dimensional steady groundwater flow subject to spatially variable recharge and transmissivity. Approximate partial differential equations are developed for the covariances and cross-covariances between the random head, transmissivity and recharge fields. Closed-form solutions of these equations are obtained using Fourier transform techniques. The resulting covariances and cross-covariances can be incorporated into a Bayesian conditioning procedure which provides optimal estimates of the recharge, transmissivity and head fields given available measurements of any or all of these random fields. Results show that head measurements contain valuable information for estimating the random recharge field. However, when recharge is treated as a spatially variable random field, the value of head measurements for estimating the transmissivity field can be reduced considerably. In a companion paper, the method is applied to a case study of the Upper Floridan Aquifer in NE Florida.

  5. Estimating the role of casual contact from the community in transmission of Bordetella pertussis to young infants

    PubMed Central

    Wendelboe, Aaron M; Hudgens, Michael G; Poole, Charles; Van Rie, Annelies

    2007-01-01

    The proportion of infant pertussis cases due to transmission from casual contact in the community has not been estimated since before the introduction of pertussis vaccines in the 1950s. This study aimed to estimate the proportion of pertussis transmission due to casual contact using demographic and clinical data from a study of 95 infant pertussis cases and their close contacts enrolled at 14 hospitals in France, Germany, Canada, and the U.S. between February 2003 and September 2004. A complete case analysis was conducted as well as multiple imputation (MI) to account for missing data for participants and close contacts who did not participate. By considering all possible close contacts, the MI analysis estimated 66% of source cases were close contacts, implying the minimum attributable proportion of infant cases due to transmission from casual contact with community members was 34% (95% CI = 24%, 44%). Estimates from the complete case analysis were comparable but less precise. Results were sensitive to changes in the operational definition of a source case, which broadened the range of MI point estimates of transmission from casual community contact to 20%–47%. We conclude that casual contact appears to be responsible for a substantial proportion of pertussis transmission to young infants. Medical subject headings (MeSH): multiple imputation, pertussis, transmission, casual contact, sensitivity analysis, missing data, community. PMID:17949498

  6. Estimating the risk of cattle exposure to tuberculosis posed by wild deer relative to badgers in England and Wales.

    PubMed

    Ward, Alastair I; Smith, Graham C; Etherington, Thomas R; Delahay, Richard J

    2009-10-01

    Wild deer populations in Great Britain are expanding in range and probably in numbers, and relatively high prevalence of bovine tuberculosis (bTB, caused by infection with Mycobacterium bovis) in deer occurs locally in parts of southwest England. To evaluate the M. bovis exposure risk posed to cattle by wild deer relative to badgers in England and Wales, we constructed and parameterized a quantitative risk model with the use of information from the literature (on deer densities, activity patterns, bTB epidemiology, and pathology) and contemporary data on deer, cattle, and badger (Meles meles) distribution and abundance. The median relative risk score for each of the four deer species studied--red (Cervus elaphus), fallow (Dama dama), and roe (Capreolus capreolus) deer, and muntjac (Muntiacus reevesi)--was lower than unity (the relative risk set for badgers, the putative main wildlife reservoir of M. bovis in England and Wales). However, the 95th percentiles associated with risk estimates were large, and the upper limits for all four deer species exceeded unity. Although M. bovis exposure risks to cattle from deer at pasture are likely to be lower than those from badgers across most areas of England and Wales where cattle are affected by bTB because these areas coincide with high-density badger populations but not high-density deer populations, we predict the presence of localized areas where relative risks posed by deer may be considerable. Moreover, wherever deer are infected, risks to cattle may be additive to those posed by badgers. There are considerable knowledge gaps associated with bTB in deer, badgers, and cattle, and data available for model parameterization were generally of low quality and high variability, and consequently model output were subject to some uncertainty. Improved estimates of the proportion of time that deer of each species spend at pasture, the likelihood and magnitude of M. bovis excretion, and local badger and deer densities appear

  7. Achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping.

    PubMed

    Semrau, Daniel; Xu, Tianhua; Shevchenko, Nikita A; Paskov, Milen; Alvarado, Alex; Killey, Robert I; Bayvel, Polina

    2017-01-01

    Achievable information rates (AIRs) of wideband optical communication systems using a ∼40  nm (∼5  THz) erbium-doped fiber amplifier and ∼100  nm (∼12.5  THz) distributed Raman amplification are estimated based on a first-order perturbation analysis. The AIRs of each individual channel have been evaluated for DP-64QAM, DP-256QAM, and DP-1024QAM modulation formats. The impact of full-field nonlinear compensation (FF-NLC) and probabilistically shaped constellations using a Maxwell-Boltzmann distribution were studied and compared to electronic dispersion compensation. It has been found that a probabilistically shaped DP-1024QAM constellation, combined with FF-NLC, yields achievable information rates of ∼75  Tbit/s for the EDFA scheme and ∼223  Tbit/s for the Raman amplification scheme over a 2000 km standard single-mode fiber transmission.

  8. 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

  9. 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.

  10. 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

  11. The Impact of Prior Information on Estimates of Disease Transmissibility Using Bayesian Tools

    PubMed Central

    Moser, Carlee B.; Gupta, Mayetri; Archer, Brett N.; White, Laura F.

    2015-01-01

    The basic reproductive number (R₀) and the distribution of the serial interval (SI) are often used to quantify transmission during an infectious disease outbreak. In this paper, we present estimates of R₀ and SI from the 2003 SARS outbreak in Hong Kong and Singapore, and the 2009 pandemic influenza A(H1N1) outbreak in South Africa using methods that expand upon an existing Bayesian framework. This expanded framework allows for the incorporation of additional information, such as contact tracing or household data, through prior distributions. The results for the R₀ and the SI from the influenza outbreak in South Africa were similar regardless of the prior information (R^0 = 1.36–1.46, μ^ = 2.0–2.7, μ^ = mean of the SI). The estimates of R₀ and μ for the SARS outbreak ranged from 2.0–4.4 and 7.4–11.3, respectively, and were shown to vary depending on the use of contact tracing data. The impact of the contact tracing data was likely due to the small number of SARS cases relative to the size of the contact tracing sample. PMID:25793993

  12. 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

  13. A mathematical framework for estimating pathogen transmission fitness and inoculum size using data from a competitive mixtures animal model.

    PubMed

    McCaw, James M; Arinaminpathy, Nimalan; Hurt, Aeron C; McVernon, Jodie; McLean, Angela R

    2011-04-01

    We present a method to measure the relative transmissibility ("transmission fitness") of one strain of a pathogen compared to another. The model is applied to data from "competitive mixtures" experiments in which animals are co-infected with a mixture of two strains. We observe the mixture in each animal over time and over multiple generations of transmission. We use data from influenza experiments in ferrets to demonstrate the approach. Assessment of the relative transmissibility between two strains of influenza is important in at least three contexts: 1) Within the human population antigenically novel strains of influenza arise and compete for susceptible hosts. 2) During a pandemic event, a novel sub-type of influenza competes with the existing seasonal strain(s). The unfolding epidemiological dynamics are dependent upon both the population's susceptibility profile and the inherent transmissibility of the novel strain compared to the existing strain(s). 3) Neuraminidase inhibitors (NAIs), while providing significant potential to reduce transmission of influenza, exert selective pressure on the virus and so promote the emergence of drug-resistant strains. Any adverse outcome due to selection and subsequent spread of an NAI-resistant strain is exquisitely dependent upon the transmission fitness of that strain. Measurement of the transmission fitness of two competing strains of influenza is thus of critical importance in determining the likely time-course and epidemiology of an influenza outbreak, or the potential impact of an intervention measure such as NAI distribution. The mathematical framework introduced here also provides an estimate for the size of the transmitted inoculum. We demonstrate the framework's behaviour using data from ferret transmission studies, and through simulation suggest how to optimise experimental design for assessment of transmissibility. The method introduced here for assessment of mixed transmission events has applicability beyond

  14. 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

  15. Cutaneous Tuberculosis

    PubMed Central

    Frankel, Amylynne; Penrose, Carolin

    2009-01-01

    Cutaneous tuberculosis occurs rarely, despite a high and increasing prevalence of tuberculosis worldwide. Mycobacterium tuberculosis, Mycobacterrium bovis, and the Bacille Calmette-Guérin vaccine can cause tuberculosis involving the skin. Cutaneous tuberculosis can be acquired exogenously or endogenously and present as a multitude of differing clinical morphologies. Diagnosis of these lesions can be difficult, as they resemble many other dermatological conditions that are often primarily considered. Further, microbiological confirmation is poor, despite scientific advances, such as the more frequent use of polymerase chain reaction. The authors report a case that illustrates the challenges faced by dermatologists when considering a diagnosis of cutaneous tuberculosis. PMID:20725570

  16. 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

  17. Factors Associated with Differences between Conventional Contact Tracing and Molecular Epidemiology in Study of Tuberculosis Transmission and Analysis in the City of Barcelona, Spain ▿

    PubMed Central

    Borrell, Sònia; Español, Montserrat; Orcau, Àngels; Tudó, Griselda; March, Francesca; Caylà, Joan A.; Jansà, Josep Maria; Alcaide, Fernando; Martín-Casabona, Núria; Salvadó, Margarita; Martínez, José Antonio; Vidal, Rafael; Sánchez, Francesca; Altet, Neus; Coll, Pere; González-Martín, Juliàn

    2009-01-01

    The aim of this study was to analyze the factors associated with conventional contact tracing (CCT) and molecular epidemiology (ME) methods in assessing tuberculosis (TB) transmission, comparing the populations studied and the epidemiological links established by both methods. Data were obtained from TB case and CCT registries, and ME was performed using IS6110-based restriction fragment length polymorphism (RFLP) analysis and mycobacterial interspersed repetitive unit 12 (MIRU12) typing as a secondary typing method. During two years (2003 and 2004), 892 cases of TB were reported, of which 687 (77%) were confirmed by culture. RFLP analysis was performed with 463 (67.4%) of the 687 isolated strains, and MIRU12 types in 75 strains were evaluated; 280 strains (60.5%) had a unique RFLP pattern, and 183 (39.5%) shared patterns, grouping into 65 clusters. CCT of 613 (68.7%) of 892 cases detected 44 clusters involving 101 patients. The results of both CCT and ME methods yielded 96 clusters involving 255 patients. The household link was the one most frequently identified by CCT (corresponding to 80.7% of the cases clustered by this method), whereas nonhousehold and unknown links were associated with 94.1% of the strains clustered by ME. When both methods were used in 351 cases (39.3%), they showed the same results in 214 cases (61%). Of the remainder, 106 (30.2%) were clustered only by ME, 19 (5.5%) were clustered only by CCT, and 12 (3.4%) were clustered by both methods but into different clusters. Patients with factors potentially associated with social problems were less frequently studied by CCT (P = 0.002), whereas patients of <15 years of age, most with negative cultures, were less frequently studied by ME (P = 0.005). Significant differences in the populations studied by ME versus CCT were observed, possibly explaining the scarce correlation found between the results of these methods. Moreover, ME allowed the detection of nonhousehold contact relationships, whereas

  18. 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

    2015-12-05

    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.

  19. Estimation of the noise contributions from blank, transmission and emission scans in PET

    SciTech Connect

    Holm, S.; Jensen, M.; Toft, P.

    1996-08-01

    This work determines the relative importance of noise from blank (B), transmission (T) and emission (E) scans in PET using a GE Advance scanner on a 20 cm cylinder, a brain phantom, and a torso-like ellipse (18/35 cm) with examples of human scans (brain O-15 water and F-18 FDG, heart FDG). Phantom E scans were acquired in both 2D and 3D modes as decay series with C-11 or F-18 over 3--6 decades of Noise Equivalent Counts (NEC). B and T scans were made using two pin sources ({approx} 500 MBq total) over 64-32768 sec. In humans only a limited subset was available. In homogeneous phantoms normalized variance (var) was estimated from pixel distributions in single images. In other objects, including the human studies, calculations were performed on differences of paired images. In all cases a fit was made to a simple noise model. The cylinder data show expected relations of T to B noise proving the adequacy of B scan times {le} 20 min for most purposes. For the brain phantom, a contour plot is provided for var (E,T). In a typical 3D O-15 water study with 0.5 M counts per central slice, a 10 min T-scan adds less than 10% to the total noise level. An example shows how to split a total scan time between E and T scans, in order to minimize the variance.

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

    PubMed Central

    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

  1. [Focus on the role of ventilation and ultraviolet rays in preventing nosocomial transmission of tuberculosis in health care facilities. Groupe de travail sur la prévention de la transmission nosocomiale de la tuberculose (Direction Générale de la Santé)].

    PubMed

    Desenclos, J C; Abiteboul, D; Bouvet, E; Brucker, G; Demeulemester, R; Haury, B; Huré, P; Leprince, A; Macrez, A; Mayaud, C

    1995-01-01

    Recent episodes of nosocomial tuberculosis, sometimes due to multiresistant strains, in HIV infected patients in the USA has led to the need for new prevention measures against the transmission of Mycobacterium tuberculosis in health care facilities. Tuberculosis is transmitted in Pflügge droplets generated when contagious persons cough. After drying, the droplets become aerosolized solid particles which are rapidly dispersed by air flow within the patient's room. People exposed to the same air are thus at high risk of being contaminated. If the air pressure in the patient's room is higher than the rest of the facility, the air coming form the room may contaminate personnel and other patients elsewhere in the facility. Infecting particles can be eliminated rapidly if the room air is ventilated outdoors. If the ventilation is strong enough so that air constantly circulates from the corridor into the room, infecting particles can no longer diffuse to the rest of the ward. It is also possible to use ultraviolet C light to disinfect the air, either within the room or within the ventilation system. These two basically simple systems are the fundamental environmental and prevention measures needed to limit tuberculosis spread in health care facilities. These methods are however technically complex, costly and require constant evaluation and maintenance by specialized personnel. In addition the potential side effects of ultraviolet waves could considerably reduce their application. These environmental methods, which are complementary methods, only have a meaning if the elementary measures for preventing the transmission of tuberculosis are correctly applied.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Lives saved by Global Fund-supported HIV/AIDS, tuberculosis and malaria programs: estimation approach and results between 2003 and end-2007

    PubMed Central

    2010-01-01

    Background Since 2003, the Global Fund has supported the scale-up of HIV/AIDS, tuberculosis and malaria control in low- and middle-income countries. This paper presents and discusses a methodology for estimating the lives saved through selected service deliveries reported to the Global Fund. Methods Global Fund-supported programs reported, by end-2007, 1.4 million HIV-infected persons on antiretroviral treatment (ARV), 3.3 million new smear-positive tuberculosis cases detected in DOTS (directly observed TB treatment, short course) programs, and 46 million insecticide-treated mosquito nets (ITNs) delivered. We estimated the corresponding lives saved using adaptations of existing epidemiological estimation models. Results By end-2007, an estimated 681,000 lives (95% uncertainty range 619,000-774,000) were saved and 1,097,000 (993,000-1,249,000) life-years gained by ARV. DOTS treatment would have saved 1.63 million lives (1.09 - 2.17 million) when compared against no treatment, or 408,000 lives (265,000-551,000) when compared against non-DOTS treatment. ITN distributions in countries with stable endemic falciparum malaria were estimated to have achieved protection from malaria for 26 million of child-years at risk cumulatively, resulting in 130,000 (27,000-232,000) under-5 deaths prevented. Conclusions These results illustrate the scale of mortality effects that supported programs may have achieved in recent years, despite margins of uncertainty and covering only selected intervention components. Evidence-based evaluation of disease impact of the programs supported by the Global Fund with international and in-country partners must be strengthened using population-level data on intervention coverage and demographic outcomes, information on quality of services, and trends in disease burdens recorded in national health information systems. PMID:20433714

  3. 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

  4. 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...

  5. 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.

  6. Nonlinear pattern of pulmonary tuberculosis among migrants at entry in Kuwait: 1997–2006

    PubMed Central

    Akhtar, Saeed; Mohammad, Hameed GHH

    2008-01-01

    Background There is a paucity of published data on the pattern of pulmonary tuberculosis among migrant workers entering Middle Eastern countries particularly Kuwait. The objectives of this study were to use routine health surveillance data i) to estimate the prevalence of pulmonary tuberculosis among migrant workers at entry in Kuwait and ii) to determine the occurrence of any time trends in the proportions of pulmonary tuberculosis positive workers over the study period. Methods The monthly aggregates of daily number of migrants tested and the number of pulmonary tuberculosis cases detected during routine health examinations of migrant workers from tuberculosis high-prevalence countries were used to generate the monthly series of proportions (per 100,000) of pulmonary tuberculosis cases over 120 months between January 1, 1997 and December 31, 2006 and analysed using time series methods. Results The overall prevalence (per 100,000) of documented pulmonary tuberculosis cases among screened migrants was 198 (4608/2328582). Year-specific prevalence (per 100,000) of tuberculosis cases consistently declined from 456 (95% CI: 424 – 490) in 1997 to 124 (95% CI: 110 – 140) in 2002 before showing a steady increase up to 183 (95% CI: 169–197) in 2006. The second-order polynomial regression model revealed significant (P < 0.001) initial decline, followed by a significant (P < 0.001) increasing trend thereafter in monthly proportions of tuberculosis cases among migrant workers. Conclusion The proportions of documented tuberculosis cases among migrant workers showed a significant nonlinear pattern, with an initial decline followed by a significant increasing trend towards the end of the study period. These findings underscore the need to maintain the current policy of migrants' screening for tuberculosis at entry. The public health authorities in Kuwait and perhaps other countries in the region may consider complementing the current screening protocol with interferon

  7. The Importance of Implementation Strategy in Scaling Up Xpert MTB/RIF for Diagnosis of Tuberculosis in the Indian Health-Care System: A Transmission Model

    PubMed Central

    Salje, Henrik; Andrews, Jason R.; Deo, Sarang; Satyanarayana, Srinath; Sun, Amanda Y.; Pai, Madhukar; Dowdy, David W.

    2014-01-01

    Background India has announced a goal of universal access to quality tuberculosis (TB) diagnosis and treatment. A number of novel diagnostics could help meet this important goal. The rollout of one such diagnostic, Xpert MTB/RIF (Xpert) is being considered, but if Xpert is used mainly for people with HIV or high risk of multidrug-resistant TB (MDR-TB) in the public sector, population-level impact may be limited. Methods and Findings We developed a model of TB transmission, care-seeking behavior, and diagnostic/treatment practices in India and explored the impact of six different rollout strategies. Providing Xpert to 40% of public-sector patients with HIV or prior TB treatment (similar to current national strategy) reduced TB incidence by 0.2% (95% uncertainty range [UR]: −1.4%, 1.7%) and MDR-TB incidence by 2.4% (95% UR: −5.2%, 9.1%) relative to existing practice but required 2,500 additional MDR-TB treatments and 60 four-module GeneXpert systems at maximum capacity. Further including 20% of unselected symptomatic individuals in the public sector required 700 systems and reduced incidence by 2.1% (95% UR: 0.5%, 3.9%); a similar approach involving qualified private providers (providers who have received at least some training in allopathic or non-allopathic medicine) reduced incidence by 6.0% (95% UR: 3.9%, 7.9%) with similar resource outlay, but only if high treatment success was assured. Engaging 20% of all private-sector providers (qualified and informal [providers with no formal medical training]) had the greatest impact (14.1% reduction, 95% UR: 10.6%, 16.9%), but required >2,200 systems and reliable treatment referral. Improving referrals from informal providers for smear-based diagnosis in the public sector (without Xpert rollout) had substantially greater impact (6.3% reduction) than Xpert scale-up within the public sector. These findings are subject to substantial uncertainty regarding private-sector treatment patterns, patient care-seeking behavior

  8. 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

  9. [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.

  10. Surveillance of bovine tuberculosis and risk estimation of a future reservoir formation in wildlife in Switzerland and Liechtenstein.

    PubMed

    Schöning, Janne Marie; Cerny, Nadine; Prohaska, Sarah; Wittenbrink, Max M; Smith, Noel H; Bloemberg, Guido; Pewsner, Mirjam; Schiller, Irene; Origgi, Francesco C; Ryser-Degiorgis, Marie-Pierre

    2013-01-01

    Bovine tuberculosis (bTB) caused by Mycobacterium bovis or M. caprae has recently (re-) emerged in livestock and wildlife in all countries bordering Switzerland (CH) and the Principality of Liechtenstein (FL). Comprehensive data for Swiss and Liechtenstein wildlife are not available so far, although two native species, wild boar (Sus scrofa) and red deer (Cervus elaphus elaphus), act as bTB reservoirs elsewhere in continental Europe. Our aims were (1) to assess the occurrence of bTB in these wild ungulates in CH/FL and to reinforce scanning surveillance in all wild mammals; (2) to evaluate the risk of a future bTB reservoir formation in wild boar and red deer in CH/FL. Tissue samples collected from 2009 to 2011 from 434 hunted red deer and wild boar and from eight diseased ungulates with tuberculosis-like lesions were tested by direct real-time PCR and culture to detect mycobacteria of the Mycobacterium tuberculosis complex (MTBC). Identification of suspicious colonies was attempted by real-time PCR, genotyping and spoligotyping. Information on risk factors for bTB maintenance within wildlife populations was retrieved from the literature and the situation regarding identified factors was assessed for our study areas. Mycobacteria of the MTBC were detected in six out of 165 wild boar (3.6%; 95% CI: 1.4-7.8) but none of the 269 red deer (0%; 0-1.4). M. microti was identified in two MTBC-positive wild boar, while species identification remained unsuccessful in four cases. Main risk factors for bTB maintenance worldwide, including different causes of aggregation often resulting from intensive wildlife management, are largely absent in CH and FL. In conclusion, M. bovis and M. caprae were not detected but we report for the first time MTBC mycobacteria in Swiss wild boar. Present conditions seem unfavorable for a reservoir emergence, nevertheless increasing population numbers of wild ungulates and offal consumption may represent a risk.

  11. Sources of error in the estimation of mosquito infection rates used to assess risk of arbovirus transmission.

    PubMed

    Bustamante, Dulce M; Lord, Cynthia C

    2010-06-01

    Infection rate is an estimate of the prevalence of arbovirus infection in a mosquito population. It is assumed that when infection rate increases, the risk of arbovirus transmission to humans and animals also increases. We examined some of the factors that can invalidate this assumption. First, we used a model to illustrate how the proportion of mosquitoes capable of virus transmission, or infectious, is not a constant fraction of the number of infected mosquitoes. Thus, infection rate is not always a straightforward indicator of risk. Second, we used a model that simulated the process of mosquito sampling, pooling, and virus testing and found that mosquito infection rates commonly underestimate the prevalence of arbovirus infection in a mosquito population. Infection rate should always be used in conjunction with other surveillance indicators (mosquito population size, age structure, weather) and historical baseline data when assessing the risk of arbovirus transmission.

  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. Estimating Plasmodium falciparum transmission rates in low-endemic settings using a combination of community prevalence and health facility data.

    PubMed

    Yukich, Joshua; Briët, Olivier; Bretscher, Michael T; Bennett, Adam; Lemma, Seblewengel; Berhane, Yemane; Eisele, Thomas P; Keating, Joseph; Smith, Thomas

    2012-01-01

    As some malaria control programs shift focus from disease control to transmission reduction, there is a need for transmission data to monitor progress. At lower levels of transmission, it becomes increasingly more difficult to measure precisely, for example through entomological studies. Many programs conduct regular cross sectional parasite prevalence surveys, and have access to malaria treatment data routinely collected by ministries of health, often in health management information systems. However, by themselves, these data are poor measures of transmission. In this paper, we propose an approach for combining annual parasite incidence and treatment data with cross-sectional parasite prevalence and treatment seeking survey data to estimate the incidence of new infections in the human population, also known as the force of infection. The approach is based on extension of a reversible catalytic model. The accuracy of the estimates from this model appears to be highly dependent on levels of detectability and treatment in the community, indicating the importance of information on private sector treatment seeking and access to effective and appropriate treatment.

  14. Effects of contact network structure on epidemic transmission trees: implications for data required to estimate network structure.

    PubMed

    Carnegie, Nicole Bohme

    2017-02-13

    Understanding the dynamics of disease spread is key to developing effective interventions to control or prevent an epidemic. The structure of the network of contacts over which the disease spreads has been shown to have a strong influence on the outcome of the epidemic, but an open question remains as to whether it is possible to estimate contact network features from data collected in an epidemic. The approach taken in this paper is to examine the distributions of epidemic outcomes arising from epidemics on networks with particular structural features to assess whether that structure could be measured from epidemic data and what other constraints might be needed to make the problem identifiable. To this end, we vary the network size, mean degree, and transmissibility of the pathogen, as well as the network feature of interest: clustering, degree assortativity, or attribute-based preferential mixing. We record several standard measures of the size and spread of the epidemic, as well as measures that describe the shape of the transmission tree in order to ascertain whether there are detectable signals in the final data from the outbreak. The results suggest that there is potential to estimate contact network features from transmission trees or pure epidemic data, particularly for diseases with high transmissibility or for which the relevant contact network is of low mean degree. Copyright © 2017 John Wiley & Sons, Ltd.

  15. 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

  16. Estimation of parameters influencing waterborne transmission of infectious hematopoietic necrosis virus (IHNV) in Atlantic salmon (Salmo salar).

    PubMed

    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 × 10(7) 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.

  17. Mycobacterium tuberculosis Infection among Asian Elephants in Captivity

    PubMed Central

    Simpson, Gary; Zimmerman, Ralph; Shashkina, Elena; Chen, Liang; Richard, Michael; Bradford, Carol M.; Dragoo, Gwen A.; Saiers, Rhonda L.; Peloquin, Charles A.; Daley, Charles L.; Planet, Paul; Narachenia, Apurva; Mathema, Barun

    2017-01-01

    Although awareness of tuberculosis among captive elephants is increasing, antituberculosis therapy for these animals is not standardized. We describe Mycobacterium tuberculosis transmission between captive elephants based on whole genome analysis and report a successful combination treatment. Infection control protocols and careful monitoring of treatment of captive elephants with tuberculosis are warranted. PMID:28221115

  18. 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

  19. 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

  20. 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

  1. 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

  2. Estimating West Nile virus transmission period in Pennsylvania using an optimized degree-day model.

    PubMed

    Chen, Shi; Blanford, Justine I; Fleischer, Shelby J; Hutchinson, Michael; Saunders, Michael C; Thomas, Matthew B

    2013-07-01

    Abstract We provide calibrated degree-day models to predict potential West Nile virus (WNV) transmission periods in Pennsylvania. We begin by following the standard approach of treating the degree-days necessary for the virus to complete the extrinsic incubation period (EIP), and mosquito longevity as constants. This approach failed to adequately explain virus transmission periods based on mosquito surveillance data from 4 locations (Harrisburg, Philadelphia, Pittsburgh, and Williamsport) in Pennsylvania from 2002 to 2008. Allowing the EIP and adult longevity to vary across time and space improved model fit substantially. The calibrated models increase the ability to successfully predict the WNV transmission period in Pennsylvania to 70-80% compared to less than 30% in the uncalibrated model. Model validation showed the optimized models to be robust in 3 of the locations, although still showing errors for Philadelphia. These models and methods could provide useful tools to predict WNV transmission period from surveillance datasets, assess potential WNV risk, and make informed mosquito surveillance strategies.

  3. Dynamics of shigellosis epidemics: estimating individual-level transmission and reporting rates from national epidemiologic data sets.

    PubMed

    Joh, Richard I; Hoekstra, Robert M; Barzilay, Ezra J; Bowen, Anna; Mintz, Eric D; Weiss, Howard; Weitz, Joshua S

    2013-10-15

    Shigellosis, a diarrheal disease, is endemic worldwide and is responsible for approximately 15,000 laboratory-confirmed cases in the United States every year. However, patients with shigellosis often do not seek medical care. To estimate the burden of shigellosis, we extended time-series susceptible-infected-recovered models to infer epidemiologic parameters from underreported case data. We applied the time-series susceptible-infected-recovered-based inference schemes to analyze the largest surveillance data set of Shigella sonnei in the United States from 1967 to 2007 with county-level resolution. The dynamics of shigellosis transmission show strong annual and multiyear cycles, as well as seasonality. By using the schemes, we inferred individual-level parameters of shigellosis infection, including seasonal transmissibilities and basic reproductive number (R0). In addition, this study provides quantitative estimates of the reporting rate, suggesting that the shigellosis burden in the United States may be more than 10 times the number of laboratory-confirmed cases. Although the estimated reporting rate is generally under 20%, and R0 is generally under 1.5, there is a strong negative correlation between estimates of the reporting rate and R0. Such negative correlations are likely to pose identifiability problems in underreported diseases. We discuss complementary approaches that might further disentangle the true reporting rate and R0.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26267223

  5. 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.

  6. Estimation of the rate of mother to child transmission of HIV in Nigeria.

    PubMed

    Audu, R A; Salu, O B; Musa, A Z; Onyewuche, J; Funso-Adebayo, E O; Iroha, E O; Ezeaka, V C; Adetifa, I M O; Okoeguale, B; Idigbe, E O

    2006-06-01

    Definitive diagnosis of HIV infection in infants < 18 months of age who were born to HIV-infected mothers is still posing some difficulty in Nigeria and other developing countries. Within this age definitive diagnosis can only be carried out by antigen based techniques which are indeed not available in these developing countries. This has resulted in the absence of authoritative data on the rate of mother-to-child transmission in these countries. Nigeria inclusive. The present pilot study was therefore carried out to generate some information on the rate of mother to child transmission in Nigeria using the PCR technique. Plasma samples were obtained from 68 children of both sexes less than 18 months of age and who were born to HIV infected mothers. The samples were collected from two pediatric departments. in Lagos and in Benin. The presence of HIV 1 RNA in each of the samples. was determined using the Amplicor Monitor V 1.5 technique (Roche Diagnostics). Data showed that HIV-1 RNA was detected in 15 of the 68 samples tested. This gave an HIV-1 RNA detection rate of 22%. Among women who had some intervention, the rate of transmission of infection was 11% while the rate among those without intervention was 30%. The 22% transmission rate recorded in this study is close to the range of 25 to 35% that has been reported in several developed and a few developing countries. A multicenter nationwide study will still be needed to determine the national mother to child transmission rate in Nigeria.

  7. [Strategical use of genotyping of Mycobacterium tuberculosis in tuberculosis control].

    PubMed

    David, Susana

    2008-01-01

    The tuberculosis situation in Portugal justifies the use of a strategy for the genotyping of Mycobacterium tuberculosis, particularly as Portugal is part of the global backdrop of human mobility, something which has a knock-on effect on the pandemic. Several international studies have placed spoligotyping and MIRU- VNTR typing as first line techniques for the molecular epidemiology of Mycobacterium tuberculosis as these techniques rely on simple technologies (PCR) and produce patterns which are easily translated into a direct interpretation numerical code. Spoligotyping has been accordingly proposed for all the isolates, while MIRU-VNTR typing should be applied to isolates with a common spoliotype. Other techniques, including IS6110-RFLP, should be reserved for use ill accordance with selected criteria. Previous studies in Portugal using spoligotyping have underlined the advantages of a strategy based on sampling consecutive patient isolates with no prior selection criteria. This allows characterisation of the M. tuberculosis population structure through monitoring the distribution of the genotypes geographically over time and within the various risk groups. On the other hand, the association of spoligotyping, MIRU-VNTF (typing and, possibly, other techniques, needs evaluating as part of bigger pictures, including identifying recent transmission situations, distinguishing between reinfection and relapse episodes and mapping the size and dynamics of disease transmission. The solution to the tuberculosis problem in Portugal implies structuring genotyping's role in tuberculosis prevention and control and its evaluation through concrete examples and results.

  8. Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling

    PubMed Central

    Olive, Marie-Marie; Grosbois, Vladimir; Tran, Annelise; Nomenjanahary, Lalaina Arivony; Rakotoarinoro, Mihaja; Andriamandimby, Soa-Fy; Rogier, Christophe; Heraud, Jean-Michel; Chevalier, Veronique

    2017-01-01

    The force of infection (FOI) is one of the key parameters describing the dynamics of transmission of vector-borne diseases. Following the occurrence of two major outbreaks of Rift Valley fever (RVF) in Madagascar in 1990–91 and 2008–09, recent studies suggest that the pattern of RVF virus (RVFV) transmission differed among the four main eco-regions (East, Highlands, North-West and South-West). Using Bayesian hierarchical models fitted to serological data from cattle of known age collected during two surveys (2008 and 2014), we estimated RVF FOI and described its variations over time and space in Madagascar. We show that the patterns of RVFV transmission strongly differed among the eco-regions. In the North-West and Highlands regions, these patterns were synchronous with a high intensity in mid-2007/mid-2008. In the East and South-West, the peaks of transmission were later, between mid-2008 and mid-2010. In the warm and humid northwestern eco-region favorable to mosquito populations, RVFV is probably transmitted all year-long at low-level during inter-epizootic period allowing its maintenance and being regularly introduced in the Highlands through ruminant trade. The RVF surveillance of animals of the northwestern region could be used as an early warning indicator of an increased risk of RVF outbreak in Madagascar. PMID:28051125

  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. 78 FR 36698 - Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for Mycobacterium tuberculosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... handling specimens and control materials with the possibility of transmission of tuberculosis infection to... materials with the possibility of transmission of tuberculosis infection to health care workers could be... infection in patients with suspected tuberculosis as compared to traditional means of diagnosis....

  11. A nonlinear programming approach for estimation of transmission parameters in childhood infectious disease using a continuous time model.

    PubMed

    Word, Daniel P; Cummings, Derek A T; Burke, Donald S; Iamsirithaworn, Sopon; Laird, Carl D

    2012-08-07

    Mathematical models can enhance our understanding of childhood infectious disease dynamics, but these models depend on appropriate parameter values that are often unknown and must be estimated from disease case data. In this paper, we develop a framework for efficient estimation of childhood infectious disease models with seasonal transmission parameters using continuous differential equations containing model and measurement noise. The problem is formulated using the simultaneous approach where all state variables are discretized, and the discretized differential equations are included as constraints, giving a large-scale algebraic nonlinear programming problem that is solved using a nonlinear primal-dual interior-point solver. The technique is demonstrated using measles case data from three different locations having different school holiday schedules, and our estimates of the seasonality of the transmission parameter show strong correlation to school term holidays. Our approach gives dramatic efficiency gains, showing a 40-400-fold reduction in solution time over other published methods. While our approach has an increased susceptibility to bias over techniques that integrate over the entire unknown state-space, a detailed simulation study shows no evidence of bias. Furthermore, the computational efficiency of our approach allows for investigation of a large model space compared with more computationally intensive approaches.

  12. A nonlinear programming approach for estimation of transmission parameters in childhood infectious disease using a continuous time model

    PubMed Central

    Word, Daniel P.; Cummings, Derek A. T.; Burke, Donald S.; Iamsirithaworn, Sopon; Laird, Carl D.

    2012-01-01

    Mathematical models can enhance our understanding of childhood infectious disease dynamics, but these models depend on appropriate parameter values that are often unknown and must be estimated from disease case data. In this paper, we develop a framework for efficient estimation of childhood infectious disease models with seasonal transmission parameters using continuous differential equations containing model and measurement noise. The problem is formulated using the simultaneous approach where all state variables are discretized, and the discretized differential equations are included as constraints, giving a large-scale algebraic nonlinear programming problem that is solved using a nonlinear primal–dual interior-point solver. The technique is demonstrated using measles case data from three different locations having different school holiday schedules, and our estimates of the seasonality of the transmission parameter show strong correlation to school term holidays. Our approach gives dramatic efficiency gains, showing a 40–400-fold reduction in solution time over other published methods. While our approach has an increased susceptibility to bias over techniques that integrate over the entire unknown state-space, a detailed simulation study shows no evidence of bias. Furthermore, the computational efficiency of our approach allows for investigation of a large model space compared with more computationally intensive approaches. PMID:22337634

  13. Risk of tuberculosis among air passengers estimated by interferon gamma release assay: survey of contact investigations, Japan, 2012 to 2015.

    PubMed

    Ota, Masaki; Kato, Seiya

    2017-03-23

    Although the World Health Organization recommends contact investigations around air travel-associated sputum smear-positive tuberculosis (TB) patients, evidence suggests that the information thus obtained may have overestimated the risk of TB infection because it involved some contacts born in countries with high TB burden who were likely to have been infected with TB in the past, or because tuberculin skin tests were used, which are less specific than the interferon gamma release assay (IGRA) particularly in areas where Bacillus Calmette-Guérin (BCG) vaccination coverage is high. We conducted a questionnaire survey on air travel-associated TB contact investigations in local health offices of Japan from 2012 to 2015, focusing on IGRA positivity. Among 651 air travel-associated TB contacts, average positivity was 3.8% (95% confidence interval (CI): 2.5-5.6) with a statistically significant increasing trend with older age (p < 0.0094). Positivity among 0-34 year-old contacts was 1.0% (95% CI: 0.12-3.5%), suggesting their risk of TB infection is as small as among Japanese young adults with low risk of TB infection (positivity: 0.85-0.90%). Limiting the contact investigation to fewer passengers (within two seats surrounding the index case, rather than two rows) seems reasonable in the case of aircraft with many seats per row.

  14. Tuberculosis in European badgers (Meles meles) and the control of infection with bacille Calmette-Guérin vaccination.

    PubMed

    Corner, L A L; Murphy, D; Costello, E; Gormley, E

    2009-10-01

    The eradication of tuberculosis (Mycobacterium bovis infection) from cattle herds may be compromised if infected wildlife species, such as European badgers (Meles meles), share the same environment and contribute to transfer of infection. Options for dealing with tuberculosis in this wild reservoir host are limited by conservation and social concerns, despite a clear implication that infected badgers are involved with the initiation of tuberculosis in cattle herds. Vaccination of badgers against M. bovis, if successfully employed, would directly facilitate the completion of bovine tuberculosis eradication in affected areas. Vaccine trials in captive badgers have established that the M. bovis bacille Calmette-Guérin (BCG) vaccine can induce a protective response that limits the distribution and severity of tuberculosis disease following experimental challenge. The protective effect of the vaccine has been demonstrated when the vaccine was delivered by subcutaneous injection, deposited on mucous membranes, and given orally in a lipid formulation. A large-scale field trial of oral BCG vaccine has been designed to measure the protection generated in wild badgers subjected to natural transmission of infection and to estimate vaccine efficacy. These parameters will be estimated by comparing the prevalence of M. bovis infection in vaccinated and nonvaccinated badgers. The results will provide a framework for the development and implementation of a national strategy to eliminate the disease in badger populations and if successful will remove this major impediment to bovine tuberculosis eradication.

  15. Tuberculosis (TB): Treatment

    MedlinePlus

    ... Training Home Conditions Tuberculosis (TB) Treating Tuberculosis Treating Tuberculosis Make an Appointment Refer a Patient Ask a ... bones is treated longer. NEXT: Preventive Treatment Diagnosing Tuberculosis History of TB Clinical Trials For more than ...

  16. 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.

  17. Comparative analysis estimates the relative frequencies of co-divergence and cross-species transmission within viral families

    PubMed Central

    Geoghegan, Jemma L.

    2017-01-01

    The cross-species transmission of viruses from one host species to another is responsible for the majority of emerging infections. However, it is unclear whether some virus families have a greater propensity to jump host species than others. If related viruses have an evolutionary history of co-divergence with their hosts there should be evidence of topological similarities between the virus and host phylogenetic trees, whereas host jumping generates incongruent tree topologies. By analyzing co-phylogenetic processes in 19 virus families and their eukaryotic hosts we provide a quantitative and comparative estimate of the relative frequency of virus-host co-divergence versus cross-species transmission among virus families. Notably, our analysis reveals that cross-species transmission is a near universal feature of the viruses analyzed here, with virus-host co-divergence occurring less frequently and always on a subset of viruses. Despite the overall high topological incongruence among virus and host phylogenies, the Hepadnaviridae, Polyomaviridae, Poxviridae, Papillomaviridae and Adenoviridae, all of which possess double-stranded DNA genomes, exhibited more frequent co-divergence than the other virus families studied here. At the other extreme, the virus and host trees for all the RNA viruses studied here, particularly the Rhabdoviridae and the Picornaviridae, displayed high levels of topological incongruence, indicative of frequent host switching. Overall, we show that cross-species transmission plays a major role in virus evolution, with all the virus families studied here having the potential to jump host species, and that increased sampling will likely reveal more instances of host jumping. PMID:28178344

  18. Model-based estimates of the effects of efavirenz on bedaquiline pharmacokinetics and suggested dose adjustments for patients coinfected with HIV and tuberculosis.

    PubMed

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

    2013-06-01

    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.

  19. Global burden of HIV, viral hepatitis, and tuberculosis in prisoners and detainees.

    PubMed

    Dolan, Kate; Wirtz, Andrea L; Moazen, Babak; Ndeffo-Mbah, Martial; Galvani, Alison; Kinner, Stuart A; Courtney, Ryan; McKee, Martin; Amon, Joseph J; Maher, Lisa; Hellard, Margaret; Beyrer, Chris; Altice, Fredrick L

    2016-09-10

    The prison setting presents not only challenges, but also opportunities, for the prevention and treatment of HIV, viral hepatitis, and tuberculosis. We did a comprehensive literature search of data published between 2005 and 2015 to understand the global epidemiology of HIV, hepatitis C virus (HCV), hepatitis B virus (HBV), and tuberculosis in prisoners. We further modelled the contribution of imprisonment and the potential impact of prevention interventions on HIV transmission in this population. Of the estimated 10·2 million people incarcerated worldwide on any given day in 2014, we estimated that 3·8% have HIV (389 000 living with HIV), 15·1% have HCV (1 546 500), 4·8% have chronic HBV (491 500), and 2·8% have active tuberculosis (286 000). The few studies on incidence suggest that intraprison transmission is generally low, except for large-scale outbreaks. Our model indicates that decreasing the incarceration rate in people who inject drugs and providing opioid agonist therapy could reduce the burden of HIV in this population. The prevalence of HIV, HCV, HBV, and tuberculosis is higher in prison populations than in the general population, mainly because of the criminalisation of drug use and the detention of people who use drugs. The most effective way of controlling these infections in prisoners and the broader community is to reduce the incarceration of people who inject drugs.

  20. [The development of tuberculosis control and tuberculosis epidemiology in East Germany].

    PubMed

    Steinbrück, P

    1983-01-01

    The fight against tuberculosis in the German Democratic Republic was performed from the very beginning as a task of the state and the society; it was developed according to the progress of economic possibilities and the epidemiological situation. The contribution of the community and of the social-economic development on tuberculosis epidemiology has proved to be decisively important factors in tuberculosis control. The specific methods applied in tuberculosis control in the course of more than 30 years have changed in their importance effectiveness and efficiency with the reduction of the tuberculosis problem and the development of new techniques. Therefore a continuous evaluation of the tuberculosis situation is necessary to recognize the most effective approach. By reducing the estimated annual infection rate to less than 0.05%, the incidence of smear positive pulmonary tuberculosis to less than 5/100,000 and the practical disappearance of tuberculosis among children tuberculosis has become an endemic localized disease among predominantly old citizens. People's mass x-ray examinations have considerably lost their value for finding tuberculosis. Early coverage and examination of persons with respiratory symptoms (21-days-coughers), of contact persons and high risk groups will determine the future activities of the chest clinics. Their integration into the system of outpatient clinics and the system of primary health care were an important step on this way. Successful treatment of each case of tuberculosis is now possible and must be attained. Early case finding + treatment considered as an united activity has become the decisively important measure in the control of tuberculosis. The endemic foci of tuberculosis in some communities have to be surveyed and eliminated with priority. Moreover, the cooperation of all physicians of public health is necessary. Only by this way tuberculosis can be eradicated in GDR in a defined time. (Aim of WHO and IUaT: 1 case of

  1. [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.

  2. 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

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

    PubMed

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

    2014-10-01

    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.

  4. Equalization of nonlinear transmission impairments by maximum-likelihood-sequence estimation in digital coherent receivers.

    PubMed

    Khairuzzaman, Md; Zhang, Chao; Igarashi, Koji; Katoh, Kazuhiro; Kikuchi, Kazuro

    2010-03-01

    We describe a successful introduction of maximum-likelihood-sequence estimation (MLSE) into digital coherent receivers together with finite-impulse response (FIR) filters in order to equalize both linear and nonlinear fiber impairments. The MLSE equalizer based on the Viterbi algorithm is implemented in the offline digital signal processing (DSP) core. We transmit 20-Gbit/s quadrature phase-shift keying (QPSK) signals through a 200-km-long standard single-mode fiber. The bit-error rate performance shows that the MLSE equalizer outperforms the conventional adaptive FIR filter, especially when nonlinear impairments are predominant.

  5. 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.

  6. Transmission map estimation of weather-degraded images using a hybrid of recurrent fuzzy cerebellar model articulation controller and weighted strategy

    NASA Astrophysics Data System (ADS)

    Wang, Jyun-Guo; Tai, Shen-Chuan; Lin, Cheng-Jian

    2016-08-01

    This study proposes a hybrid of a recurrent fuzzy cerebellar model articulation controller (RFCMAC) and a weighted strategy for solving single-image visibility in a degraded image. The proposed RFCMAC model is used to estimate the transmission map. The average value of the brightest 1% in a hazy image is calculated for atmospheric light estimation. A new adaptive weighted estimation is then used to refine the transmission map and remove the halo artifact from the sharp edges. Experimental results show that the proposed method has better dehazing capability compared to state-of-the-art techniques and is suitable for real-world applications.

  7. Estimation, transmission, and distribution of motion information in future image communication networks

    NASA Astrophysics Data System (ADS)

    Chupeau, Bertrand

    1993-10-01

    There is no doubt that in a near future a large number of image processing techniques will be based on motion compensation, making thus very common the cascading of several 'motion compensated' devices in the same image chain. A reference scheme for the optimum use of motion compensation in future image communication networks is presented. Motion estimation is performed once only, at a very early stage of the process chain, then motion information is encoded, transmitted in a separate data channel and distributed to the cascaded motion compensated processes. The distribution scenario must take into consideration the various transformations performed on the image signal since its origination so that the motion information distributed is always consistent with the pictures to process. The problems of the representation of motion relatively to a given source image signal and of its adjustment to new frame rate environments are especially addressed.

  8. Nonlinear mitigation using carrier phase estimation and digital backward propagation in coherent QAM transmission.

    PubMed

    Lin, Chien-Yu; Asif, Rameez; Holtmannspoetter, Michael; Schmauss, Bernhard

    2012-12-10

    We investigate the performance of carrier phase estimation (CPE) and digital backward propagation (DBP) in compensating fiber nonlinearity for 224 Gbps polarization-multiplexed quadrature-amplitude-modulation coherent systems with level of 4 and 16 (PM-4-QAM and PM-16-QAM) over standard single-mode fiber (SSMF) uncompensated link. The results from numerical simulation show the individual performance of CPE and DBP as well as their mutual influence. With DBP compensation, required CPE tap number for optimal performance can be reduced by 50% for 4-QAM signal and 67% for 16-QAM signal compared to linear compensation. On the other hand, employing CPE compensation after DBP also allows to reduce DBP steps. In the mentioned PM-16-QAM system, 60% reduction in the required number of DBP steps to achieve BER=10(-3) is possible, with a step-size of 200 km, which reveals great potential to reduce the complexity for future real time implementation.

  9. Estimation of the Effective Number of Founders That Initiate an Infection after Aphid Transmission of a Multipartite Plant Virus ▿

    PubMed Central

    Betancourt, Mónica; Fereres, Alberto; Fraile, Aurora; García-Arenal, Fernando

    2008-01-01

    The fecundity of RNA viruses can be very high. Thus, it is often assumed that viruses have large populations, and RNA virus evolution has been mostly explained using purely deterministic models. However, population bottlenecks during the virus life cycle could result in effective population numbers being much smaller than reported censuses, and random genetic drift could be important in virus evolution. A step at which population bottlenecks may be severe is host-to-host transmission. We report here an estimate of the size of the population that starts a new infection when Cucumber mosaic virus (CMV) is transmitted by the aphid Aphis gossypii, based on the segregation of two CMV genotypes in plants infected by aphids that acquired the virus from plants infected by both genotypes. Results show very small effective numbers of founders, between one and two, both in experiments in which the three-partite genome of CMV was aphid transmitted and in experiments in which a fourth RNA, CMV satellite RNA, was also transmitted. These numbers are very similar to those published for Potato virus Y, which has a monopartite genome and is transmitted by aphids according to a different mechanism than CMV. Thus, the number of genomic segments seems not to be a major determinant of the effective number of founders. Also, our results suggest that the occurrence of severe bottlenecks during horizontal transmission is general for viruses nonpersistently transmitted by aphids, indicating that random genetic drift should be considered when modeling virus evolution. PMID:18842732

  10. 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).

  11. 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.

  12. Monitoring and modelling of pumping-induced self-potentials for transmissivity estimation within a heterogeneous confined aquifer

    NASA Astrophysics Data System (ADS)

    DesRoches, Aaron J.; Butler, Karl E.

    2016-12-01

    Variations in self-potentials (SP) measured at surface during pumping of a heterogeneous confined fractured rock aquifer have been monitored and modelled in order to investigate capabilities and limitations of SP methods in estimating aquifer hydraulic properties. SP variations were recorded around a pumping well using an irregular grid of 31 non-polarizing Pb-PbCl2 that were referenced to a remote electrode and connected to a commercial multiplexer and digitizer/data logger through a passive lowpass filter on each channel. The lowpass filter reduced noise by a factor of 10 compared to levels obtained using the data logger's integration-based sampling method for powerline noise suppression alone. SP signals showed a linear relationship with water levels observed in the pumping and monitoring wells over the pumping period, with an apparent electrokinetic coupling coefficient of -3.4 mV · m-1. Following recent developments in SP methodology, variability of the SP response between different electrodes is taken as a proxy for lateral variations in hydraulic head within the aquifer and used to infer lateral variations in the aquifer's apparent transmissivity. In order to demonstrate the viability of this approach, SP is modelled numerically to determine its sensitivity to (i) lateral variations in the hydraulic conductivity of the confined aquifer and (ii) the electrical conductivity of the confining layer and conductive well casing. In all cases, SP simulated on the surface still varies linearly with hydraulic head modelled at the base on the confining layer although the apparent coupling coefficient changes to varying degrees. Using the linear relationship observed in the field, drawdown curves were inferred for each electrode location using SP variations observed over the duration of the pumping period. Transmissivity estimates, obtained by fitting the Theis model to inferred drawdown curves at all 31 electrodes, fell within a narrow range of (2.0-4.2) × 10-3 m2

  13. [Extrapulmonary tuberculosis].

    PubMed

    Mazza-Stalder, J; Nicod, L; Janssens, J-P

    2012-04-01

    Extrapulmonary tuberculosis represents an increasing proportion of all cases of tuberculosis reaching 20 to 40% according to published reports. Extrapulmonary TB is found in a higher proportion of women, black people and immunosuppressed individuals. A significant proportion of cases have a normal chest X-Ray at the time of diagnosis. The most frequent clinical presentations are lymphadenitis, pleuritis and osteoarticular TB. Peritoneal, urogenital or meningeal tuberculosis are less frequent, and their diagnosis is often difficult due to the often wide differential diagnosis and the low sensitivity of diagnostic tests including cultures and genetic amplification tests. The key clinical elements are reported and for each form the diagnostic yield of available tests. International therapeutic recommendations and practical issues are reviewed according to clinical presentation.

  14. MULTIFOCAL TUBERCULOSIS VERRUCOSA CUTIS

    PubMed Central

    Rajan, Jiby; Mathai, Ashok Thomas; Prasad, P V S; Kaviarasan, P K

    2011-01-01

    Tuberculosis has been a well-known affliction of human kind, since antiquity. Cutaneous tuberculosis constitutes only a small proportion of extra pulmonary tuberculosis and multifocal involvement of cutaneous tuberculosis is an even rarer manifestation. We report one such case of multifocal tuberculosis verrucosa cutis in a 17-year old male patient in the absence of any primary tuberculous focus. PMID:21772603

  15. Tuberculosis of the Gallbladder

    PubMed Central

    Kumar, K.; Ayub, M.; Kumar, Mohan; Keswani, N. K.

    2000-01-01

    Analysis of 5 patients with gallbladder tuberculosis who had open cholecystectomy and review of literature have shown that, although still rare it presents as a part of systemic miliary tuberculosis, abdominal tuberculosis, isolated gallbladder tuberculosis and as acalculus cholecystitis in anergic patients. There are no pathognomonic signs, the diagnosis depends on suspicion of tuberculosis, peroperative findings and histological examination. PMID:10977119

  16. Estimation of mass thickness response of embedded aggregated silica nanospheres from high angle annular dark-field scanning transmission electron micrographs.

    PubMed

    Nordin, M; Abrahamsson, C; Blomqvist, C H; Häbel, H; Röding, M; Olsson, E; Nydén, M; Rudemo, M

    2014-02-01

    In this study, we investigate the functional behaviour of the intensity in high-angle annular dark field scanning transmission electron micrograph images. The model material is a silica particle (20 nm) gel at 5 wt%. By assuming that the intensity response is monotonically increasing with increasing mass thickness of silica, an estimate of the functional form is calculated using a maximum likelihood approach. We conclude that a linear functional form of the intensity provides a fair estimate but that a power function is significantly better for estimating the amount of silica in the z-direction. The work adds to the development of quantifying material properties from electron micrographs, especially in the field of tomography methods and three-dimensional quantitative structural characterization from a scanning transmission electron micrograph. It also provides means for direct three-dimensional quantitative structural characterization from a scanning transmission electron micrograph.

  17. Genotypic characteristics of Mycobacterium tuberculosis isolated from household contacts of tuberculosis patients in the Philippines

    PubMed Central

    2013-01-01

    Background The Philippines has an extremely high rate of tuberculosis but little is known about M. tuberculosis genotypes and transmission dynamics in this country. The aim of this study was to determine the proportion of household contacts who develop active TB due to direct transmission from an index case in that household. Methods Mycobacterium tuberculosis isolates from household contacts of tuberculosis patients in the Philippines were characterized using restriction-fragment-length polymorphism analysis, spoligotyping, and mycobacterial interspersed repetitive units – variable number tandem repeats typing (12-loci) to determine their utility in elucidating transmission in an area of high tuberculosis prevalence. Drug susceptibility patterns for these isolates were also determined. Results Spoligotyping and MIRU-VNTR typing results matched in 10 (62.5%) of 16 index patient-household contact pairs while IS6110 fingerprints matched in only six (37.5%) pairs. Only 3/16 (18.8%) index patient-household contact pairs had identical drug susceptibility results. Conclusions Strain typing of M. tuberculosis isolates from household contacts in the Philippines indicates that transmission of strains does not necessarily occur directly from the index patient living in close proximity in the same household but rather that community-based transmission also frequently occurs. Accurate susceptibility testing of all isolates is necessary to insure optimal care of both the index patients and any culture-positive household contacts. PMID:24308751

  18. Tuberculosis in indigenous communities of Antioquia, Colombia: epidemiology and beliefs.

    PubMed

    Hernández Sarmiento, José Mauricio; Dávila Osorio, Victoria Lucia; Martínez Sánchez, Lina María; Restrepo Serna, Laura; Grajales Ospina, Diana Carolina; Toro Montoya, Andrés Eduardo; Arango Urrea, Verónica; Vargas Grisales, Natalia; Estrada Gómez, Manuela; Lopera Valle, Johan Sebastián; García Gil, Juan José; Restrepo, Lady; Mejía, Gloria; Zapata, Elsa; Gómez, Verónica; Lopera, Diver; Domicó Domicó, José Leonardo; Robledo, Jaime

    2013-02-01

    Morbidity and mortality caused by tuberculosis are increased in most of the Latin-American indigenous communities. Factors that could explain this situation are poverty and limited health services access due to social conflicts and geographical isolation. We determined the frequency of tuberculosis in Colombian indigenous communities and described their knowledge related to transmission and control. We developed a descriptive study and health survey. Interviews were performed to find ancestral knowledge about tuberculosis. Sputum samples from patients with respiratory symptoms were analyzed. 10 indigenous communities were studied, which tuberculosis incidence was 291/100,000. Communities believe that tuberculosis is a body and spirit disease, which transmission is by direct contact or by witchcraft. Tuberculosis incidence in the studied communities was ninefold higher than that of the general population from Antioquia Department. Knowledge exchange could facilitate the community empowerment and implementation of educational activities which might improve the control of the disease.

  19. Frequency and predictors of estimated HIV transmissions and bacterial STI acquisition among HIV-positive patients in HIV care across three continents

    PubMed Central

    Safren, Steven A; Hughes, James P; Mimiaga, Matthew J; Moore, Ayana T; Friedman, Ruth Khalili; Srithanaviboonchai, Kriengkrai; Limbada, Mohammed; Williamson, Brian D; Elharrar, Vanessa; Cummings, Vanessa; Magidson, Jessica F; Gaydos, Charlotte A; Celentano, David D; Mayer, Kenneth H

    2016-01-01

    Introduction Successful global treatment as prevention (TasP) requires identifying HIV-positive individuals at high risk for transmitting HIV, and having impact via potential infections averted. This study estimated the frequency and predictors of numbers of HIV transmissions and bacterial sexually transmitted infection (STI) acquisition among sexually active HIV-positive individuals in care from three representative global settings. Methods HIV-positive individuals (n=749), including heterosexual men, heterosexual women and men who have sex with men (MSM) in HIV care, were recruited from Chiang Mai (Thailand), Rio De Janeiro (Brazil) and Lusaka (Zambia). Participants were assessed on HIV and STI sexual transmission risk variables, psychosocial characteristics and bacterial STIs at enrolment and quarterly for 12 months (covering 15 months). Estimated numbers of HIV transmissions per person were calculated using reported numbers of partners and sex acts together with estimates of HIV transmissibility, accounting for ART treatment and condom use. Results An estimated 3.81 (standard error, (SE)=0.63) HIV transmissions occurred for every 100 participants over the 15 months, which decreased over time. The highest rate was 19.50 (SE=1.68) for every 100 MSM in Brazil. In a multivariable model, country×risk group interactions emerged: in Brazil, MSM had 2.85 (95% CI=1.45, 4.25, p<0.0001) more estimated transmissions than heterosexual men and 3.37 (95% CI=2.01, 4.74, p<0.0001) more than heterosexual women over the 15 months. For MSM and heterosexual women, the combined 12-month STI incidence rate for the sample was 22.4% (95% CI=18.1%, 27.3%; incidence deemed negligible in heterosexual men). In the multivariable model, MSM had 12.3 times greater odds (95% CI=4.44, 33.98) of acquiring an STI than women, but this was not significant in Brazil. Higher alcohol use on the Alcohol Use Disorders Identification Test (OR=1.04, 95% CI=1.01, 1.08) was also significantly associated

  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 and mental health in the Asia-Pacific

    PubMed Central

    Mason, Paul H; Sweetland, Annika C; Fox, Greg J; Halovic, Shaun; Nguyen, Thu Anh; Marks, Guy B

    2017-01-01

    Objective This opinion piece encourages mental health researchers and clinicians to engage with mental health issues among tuberculosis patients in the Asia-Pacific region in a culturally appropriate and ethical manner. The diversity of cultural contexts and the high burden of tuberculosis throughout the Asia-Pacific presents significant challenges. Research into tuberculosis and mental illness in this region is an opportunity to develop more nuanced models of mental illness and treatment, while simultaneously contributing meaningfully to regional tuberculosis care and prevention. Conclusions We overview key issues in tuberculosis and mental illness co-morbidity, highlight ethical concerns and advocate for a regional approach to tuberculosis and mental health that is consistent with the transnational challenges presented by this airborne infectious disease. Integrating tuberculosis and mental health services will go a long way to addressing the needs of vulnerable populations and stopping the transmission of one of the world’s biggest infectious killers. PMID:27206468

  2. Getting to Zero: Tuberculosis Elimination in California.

    PubMed

    Barry, Pennan M; Kay, Alexander W; Flood, Jennifer M; Watt, James

    This review of tuberculosis epidemiology is intended to provide a historical perspective on the public health approach to tuberculosis (TB) control in California. This historical context offers a lens through which to view current epidemiologic trends and insight into how new therapeutic tools can be applied. Since 1993, the year detailed case reporting was instituted, California has had a decrease in recent TB transmission as evidenced by a reduction in pediatric cases and an increased percentage of cases attributable to progression of latent infection to TB disease in the foreign-born population. Overall, there has been a dramatic decline in the annual TB case count, but the speed of the decline has slowed over the last several years. At the current pace and case count of 2137 in 2015, California will not achieve TB elimination (<1 TB case per one million population) for at least 100 years. There are an estimated 2.1 million persons in California with latent TB infection. Modeling suggests that LTBI detection and treatment are important in reaching TB elimination. For this reason, a coalition of stakeholders in California is exploring novel approaches to accelerate the case decline in order to prevent unnecessary disease and death.

  3. 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.

  4. 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

  5. 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.

  6. 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...

  7. HIV and Tuberculosis (TB)

    MedlinePlus

    ... AIDS-Related Opportunistic Infections and Coinfections HIV and Tuberculosis (TB) (Last updated 9/1/2016; last reviewed ... depends on a person’s individual circumstances. What is tuberculosis? Tuberculosis (TB) is a contagious disease that can ...

  8. 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 ...

  9. Mycobacterium Tuberculosis in Spinal Tuberculosis

    PubMed Central

    Kim, Sung-Sim; Moon, Han-Lim; Kim, Dong-Hyeon

    2017-01-01

    Even in an era of remarkable medical advances, there is an issue of why tuberculosis remains in the list of disastrous diseases, afflicting humans and causing suffering. There has not been a plausible answer to this, and it has been suggested that clinicians and medical scientists could presently not win the war against the tubercle bacilli. With regards to this issue, based on the authors' own clinical and research experiences, in this review, the available literature was revisited in order to address the raised questions and to provide recent information on characteristics of tubercle bacilli and possible ways to more effectively treat tuberculosis. PMID:28243382

  10. Rationale and methods for the National Tuberculosis Genotyping and Surveillance Network.

    PubMed

    Castro, Kenneth G; Jaffe, Harold W

    2002-11-01

    Our understanding of tuberculosis (TB) transmission dynamics has been refined by genotyping of Mycobacterium tuberculosis strains. The National Tuberculosis Genotyping and Surveillance Network was designed and implemented to systematically evaluate the role of genotyping technology in improving TB prevention and control activities. Genotyping proved a useful adjunct to investigations of outbreaks, unusual clusters, and laboratory cross-contamination.

  11. [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

  12. [Multidrug-resistant tuberculosis. Epidemiology, treatment, prevention and diagnostic research].

    PubMed

    Perronne, C; de Truchis, P

    1995-01-01

    The recent augmentation of the prevalence of multidrug resistant (MDR) tuberculosis is related to the high incidence of tuberculosis in HIV infected people, especially in those with low social status and no medical care; several nosocomial epidemics of MDR tuberculosis were observed in American and European institutions where HIV-infected persons were hospitalized; these MDR tuberculosis were associated with a high mortality-rate and frequent nosocomial transmission to immunocompromised contacts and care workers. The rapid institution of an adequate treatment with ancient antituberculosis agents (cycloserin, capreomycin, aminoglycosides) and/or new drugs (rifabutine, ofloxacin, sparfloxacin, etc) is necessary to avoid mortality and to diminish transmission. Prevention of MDR tuberculosis transmission is very important: patient isolation, adequate and prolonged therapy, better detection of resistance with gene-amplification methods (PCR) which are under investigation.

  13. A Perspective of the Diagnosis and Management of Congenital Tuberculosis

    PubMed Central

    Saramba, Manou Irmina

    2016-01-01

    Tuberculosis continues to be a prevalent disease in the world and a global public health issue in many countries. The disease is more complicated in pregnant women because it imperils unborn offspring and results in congenital tuberculosis later if undiagnosed and untreated. Congenital tuberculosis is rare entity and an uncommon disease along with a high mortality rate. Congenital tuberculosis, a severe clinical type of tuberculosis caused by Mycobacterium tuberculosis, is a serious and fatal disease if left untreated. Our study emphasizes that it is necessary and mandatory to consider congenital tuberculosis in the differential diagnosis of neonatal or pulmonary infections in infants, essentially in countries where the incidence of tuberculosis is high burden. Mother to neonatal transmission of disease is well known via transplacental transmission through the umbilical vein to the fetus, through the ingestion of infected amniotic fluid. Early detection is challenging, because of the nonspecific nature of the signs and symptoms in tuberculosis during pregnancy and infancy. The degree of clinical suspicion is the essential component of diagnosis. Furthermore, it generally has a difficult treatment and it should not be delayed while waiting for diagnostic test results. Prompt identification and proper treatment regimens for congenital tuberculosis strongly relate with enhanced outcomes. PMID:27999684

  14. Pre-fixation of virulent Mycobacterium tuberculosis with glutaraldehyde preserves exquisite ultrastructure on transmission electron microscopy through cryofixation and freeze-substitution with osmium-acetone at ultralow temperature.

    PubMed

    Yamada, Hiroyuki; Chikamatsu, Kinuyo; Aono, Akio; Mitarai, Satoshi

    2014-01-01

    Sample preparations for transmission electron microscopy of virulent Mycobacterium tuberculosis are usually performed with chemical fixation using glutaraldehyde (GA) in a biosafety area followed by post-fixation with aqueous osmium tetroxide (OT) in a conventional laboratory outside the biosafety area. Freeze-substitution with osmium-acetone (OA) at ultralow temperature (-85°C) has been shown to provide high quality final images and preserves cellular structures intact. However, some preparation procedures for freeze-substitution often require large fixed devices for freezing in a special laboratory. We have reported a novel freeze-substitution preparation method that can be performed using a portable device in a biosafety cabinet at biosafety level (BSL) 3 areas. Here, as a next step, we examined whether images obtained from rapid freeze-substitution (RFS) after fixation with glutaraldehyde (GA>RFS) are of comparable quality to those obtained using standard RFS. GA>RFS provided excellent preservation of mycobacterial cell ultrastructure, including visualization of cytoplasmic ribosomes, DNA fibers, and the outer membrane. The average number of ribosomes per cubic micrometer counted on RFS and GA>RFS was not significantly different (6987.8±2181.0 and 6888.9±1799.3, respectively). These values were higher, but not significantly so, than those obtained using conventional chemical fixation (5018.7±2511.3). This procedure may be useful for RFS preparation of unculturable mycobacteria strains or virulent strains isolated in laboratories that cannot perform RFS.

  15. 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%).

  16. Bovine tuberculosis in a wild boar (Sus scrofa) in Poland.

    PubMed

    Krajewska, Monika; Lipiec, Marek; Zabost, Anna; Augustynowicz-Kopeć, Ewa; Szulowski, Krzysztof

    2014-10-01

    Poland is officially tuberculosis free and bovine tuberculosis (BTB) cases are rarely found except in bovids. We found BTB in a wild boar (Sus scrofa) in the Bieszczady Mountains, southeastern Poland. Studies suggest possible transmission of infection between free-living European bison (Bison bonasus caucasicus) and wild boar in this area.

  17. Is tuberculosis a lymphatic disease with a pulmonary portal?

    PubMed

    Behr, Marcel A; Waters, W Ray

    2014-03-01

    Tuberculosis most commonly presents as a pulmonary disease, in which infection, persistence, and induction of transmissible pathology all occur in the lungs. If viewed as a pulmonary disease, enlarged lymph nodes represent reactive adenitis, and extrapulmonary forms of tuberculosis (including lymphatic tuberculosis) are not transmissible, hence representing an evolutionary dead-end for the pathogen. In an alternative theory, Mycobacterium tuberculosis passes asymptomatically through the lungs and rapidly establishes a chronic lymphatic infection. After a period of weeks to decades secondary lung pathology develops, ultimately allowing transmission to occur. Evidence that supports this lymphatic model includes historical descriptions of human tuberculosis from the preantibiotic era, analogy with other mycobacterial infections, observations of tuberculosis in non-human hosts, and experimental models of tuberculosis disease. At a fundamental level, a lymphocentric model proposes that spread of organisms outside the lung parenchyma is essential to induce adaptive immunity, which is crucial for the generation of transmissible pathology. Furthermore, a lymphatic model could explain why the lesion associated with primary infection (Ghon focus) is anatomically separated from the most common site of reactivation disease (the apex). More practically, an alternative perspective that classes tuberculosis as a lymphatic disease might affect strategies for preclinical and clinical assessment of novel diagnostics, drugs, and vaccines.

  18. Immunological consequences of strain variation within the Mycobacterium tuberculosis complex

    PubMed Central

    Tientcheu, Leopold D.; Ndengane, Mthawelenga; Andoseh, Genevieve; Kampmann, Beate; Wilkinson, Robert J

    2017-01-01

    In 2015, there were an estimated 10.4 million new cases of tuberculosis (TB) globally, making it one of the leading causes of death due to an infectious disease. TB is caused by members of the Mycobacterium tuberculosis complex (MTBC), with human disease resulting from infection by M. tuberculosis sensu stricto and M. africanum. Recent progress in genotyping techniques, in particular the increasing availability of whole genome sequence data, has revealed previously under appreciated levels of genetic diversity within the MTBC. Several studies have shown that this genetic diversity may translate into differences in TB transmission, clinical manifestations of disease, and host immune responses. This suggests the existence of MTBC genotype‐dependent host–pathogen interactions which may influence the outcome of infection and progression of disease. In this review, we highlight the studies demonstrating differences in innate and adaptive immunological outcomes consequent on MTBC genetic diversity, and discuss how these differences in immune response might influence the development of TB vaccines, diagnostics and new therapies. PMID:28150302

  19. Estimation of the reproduction ratio (R(0)) of bluetongue based on serological field data and comparison with other BTV transmission models.

    PubMed

    Santman-Berends, I M G A; Stegeman, J A; Vellema, P; van Schaik, G

    2013-03-01

    Bluetongue virus serotype 8 (BTV-8) emerged in north-western Europe in 2006. In 2007, one of the affected countries (the Netherlands) implemented a sentinel network in dairy cattle. This data offered the opportunity to estimate transmission parameters. From our field data, the number of secondary infected cows that became infected by one infectious cow in a completely susceptible herd through the bites of infectious Culicoides i.e. the basic reproduction ratio (R(0)) was calculated. With that information, the R(0) of BTV-8 was estimated using an formulae of a general SIR model. In 2007, the BTV-8 epidemic started in the south and spread northwards in the following months. R(0) could be estimated for 197 herds in which transmission occurred. The median R(0) was 2.3 and the mean R(0) was 3.7 (5th percentile=1.8; 95th percentile=11.0). In the northern region where BTV-8 transmission occurred later in the season with less favorable conditions for transmission, R(0) remained significantly lower than in the south. Our model differed from earlier published more theoretical models on BTV-8 transmission because we estimated transmission from serological field data while other models used literature based assumptions for the majority of the parameters included in their models. Although there were many differences between our model and the previously developed more theoretical models, the results showed similar ranges of R(0) for BTV-8. The reasons for the similarity between the results may be that, although the part of the vector was not included with parameters in our model, the transmission based on serological field data in cows represented both BTV-8 transmission influenced by cows and by its vector, Culicoides. Furthermore, in the earlier models the assumptions made on the vector part, although derived from literature, probably gave a good representation of the true behavior of the Culicoides species that were associated with BTV-8 transmission in north-western Europe.

  20. Abdominal tuberculosis.

    PubMed Central

    Kapoor, V. K.

    1998-01-01

    Tuberculosis has staged a global comeback and forms a dangerous combination with AIDS. The abdomen is one of the common sites of extrapulmonary involvement. Patients with abdominal tuberculosis have a wide range and spectrum of symptoms and signs; the disease is therefore a great mimic. Diagnosis, mainly radiological and supported by endoscopy, is difficult to make and laparotomy is required in a large number of patient. Management involves judicious combination of antitubercular therapy and surgery which may be required to treat complications such as intestinal obstruction and perforation. The disease, though potentially curable, carries a significant morbidity and mortality. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 PMID:9926119

  1. [Tuberculosis, today].

    PubMed

    Scala, Raffaele

    2012-06-01

    Tuberculosis is still a major health and social problem because, on the one hand, we have witnessed the dismantling of the sanatoriums, with a reduced level of diagnostic suspicion, knowledge and expertise on the management of the disease, while, the other side, are considered migratory flows, the lower socio-economic faced by immigrants, the states of immunosuppression associated with HIV prevalence of malnutrition and other diseases, and the phenomenon of multidrug-resistance, which often turns out to be iatrogenic. The success of the strategy of control/elimination of tuberculosis promoted by the World Health Organization requires a well coordinated multidisciplinary approach in which everyone does their part, the general practitioner, the pulmonologist, the infectious disease specialist, and the microbiologist.

  2. Congenital tuberculosis: presentation of a rare case.

    PubMed

    Şen, Velat; Selimoğlu Şen, Hadice; Aktar, Fesih; Uluca, Ünal; Karabel, Müsemma; Fuat Gürkan, Mehmet

    2015-04-01

    Congenital tuberculosis is a rare disease with a high mortality rate. Congenital tuberculosis is considered the result of mother-to-child transmission from the placenta to the fetus, through the ingestion of the amniotic fluid, or via transplacental transmission through the umbilical vein. Given the non-specific clinical signs of tuberculosis, it is usually difficult to diagnose it. The case of a 48-day-old male infant hospitalized due to weight loss, fever, cough, hemoptysis, and respiratory distress for the past 20 days, is presented. In this period, he had received broad spectrum antibiotics but with no improvement. A chest x-ray showed the presence of consolidation and a cavitary lesion in the upper and middle left lung fields. Mycobacterium tuberculosis was detected by polymerase chain reaction in a bronchoalveolar lavage specimen. Congenital tuberculosis was diagnosed based on this finding; hence, a tuberculostatic regimen was started accordingly. The patient died 13 days after treatment initiation. Congenital tuberculosis should be considered in infants with weight loss, fever, cough, hemoptysis and respiratory distress.

  3. Tuberculosis (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Tuberculosis KidsHealth > For Parents > Tuberculosis A A A What's in this article? Signs ... When to You Call the Doctor en español Tuberculosis Tuberculosis (popularly known as "TB") is a disease ...

  4. Tuberculosis (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Tuberculosis KidsHealth > For Parents > Tuberculosis Print A A A What's in this article? ... When to You Call the Doctor en español Tuberculosis Tuberculosis (popularly known as "TB") is a disease ...

  5. Prevalence of latent tuberculosis infection among tuberculosis laboratory workers in Iran

    PubMed Central

    2017-01-01

    OBJECTIVES The risk of transmission of Mycobacterium tuberculosis from patients to health care workers (HCWs) is a neglected problem in many countries, including Iran. The aim of this study was to estimate the prevalence of latent tuberculosis (TB) infection (LTBI) among TB laboratory staff in Iran, and to elucidate the risk factors associated with LTBI. METHODS All TB laboratory staff (689 individuals) employed in the TB laboratories of 50 Iranian universities of medical sciences and a random sample consisting of 317 low-risk HCWs were included in this cross-sectional study. Participants with tuberculin skin test indurations of 10 mm or more were considered to have an LTBI. RESULTS The prevalence of LTBI among TB laboratory staff and low-risk HCWs was 24.83% (95% confidence interval [CI], 21.31 to 27.74%) and 14.82% (95% CI, 11.31 to 19.20%), respectively. No active TB cases were found in either group. After adjusting for potential confounders, TB laboratory staff were more likely to have an LTBI than low-risk HCWs (prevalence odds ratio, 2.06; 95% CI, 1.35 to 3.17). CONCLUSIONS This study showed that LTBI are an occupational health problem among TB laboratory staff in Iran. This study reinforces the need to design and implement simple, effective, and affordable TB infection control programs in TB laboratories in Iran. PMID:28092930

  6. 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.

  7. Palaeogenomics of Mycobacterium tuberculosis: epidemic bursts with a degrading genome.

    PubMed

    Djelouadji, Zoheira; Raoult, Didier; Drancourt, Michel

    2011-08-01

    Genome-scale analysis suggests that the last common ancestor of the Mycobacterium tuberculosis complex and Mycobacterium leprae diverged 36 million years ago, and members of the Mycobacterium tuberculosis complex differentiated 40,000 years ago. Analysis of palaeomicrobiological data from a 17,000-year-old sample from a bison and a 9000-year-old sample from a human being suggested that M tuberculosis preceded Mycobacterium bovis and related species. Whole-genome comparisons show that members of the M tuberculosis complex form a unique bacterial species with distinct ecotypes that are transmissible from any infected mammalian species to several others. Genomic deletions identified several M tuberculosis lineages that could be placed on a phylogeographical map, suggesting adaptation to local host populations. The degrees of transmissibility and virulence vary between M tuberculosis clones, with increased virulence mainly linked to gene loss in regulatory pathways. Such data suggest that most M tuberculosis clones have a restricted spreading capacity between the host population, allowing unpredictable bursts of highly transmissible, virulent, and successful clones, such as the east Asian (Beijing) clone. Advances in genomics have helped the development of molecular techniques for accurate identification of species and clones in the M tuberculosis complex, which is essential for tracing the source of infections.

  8. Prioritizing Tuberculosis Clusters by Genotype for Public Health Action, Washington, USA

    PubMed Central

    Allen, Sheanne; Field, Kim; Ghosh, Smita; Haddad, Maryam B.; Narita, Masahiro; Oren, Eyal

    2013-01-01

    Groups of tuberculosis cases with indistinguishable Mycobacterium tuberculosis genotypes (clusters) might represent recent transmission. We compared geospatial concentration of genotype clusters with independent priority rankings determined by local public health officials; findings were highly correlated. Routine use of geospatial statistics could help health departments identify recent disease transmission. PMID:23621956

  9. Prioritizing tuberculosis clusters by genotype for public health action, Washington, USA.

    PubMed

    Lindquist, Scott; Allen, Sheanne; Field, Kim; Ghosh, Smita; Haddad, Maryam B; Narita, Masahiro; Oren, Eyal

    2013-03-01

    Groups of tuberculosis cases with indistinguishable Mycobacterium tuberculosis genotypes (clusters) might represent recent transmission. We compared geospatial concentration of genotype clusters with independent priority rankings determined by local public health officials; findings were highly correlated. Routine use of geospatial statistics could help health departments identify recent disease transmission.

  10. The role of screening and treatment in the transmission dynamics of HIV/AIDS and tuberculosis co-infection: a mathematical study.

    PubMed

    Kaur, Navjot; Ghosh, Mini; Bhatia, S S

    2014-03-01

    In this paper, we present a deterministic non-linear mathematical model for the transmission dynamics of HIV and TB co-infection and analyze it in the presence of screening and treatment. The equilibria of the model are computed and stability of these equilibria is discussed. The basic reproduction numbers corresponding to both HIV and TB are found and we show that the disease-free equilibrium is stable only when the basic reproduction numbers for both the diseases are less than one. When both the reproduction numbers are greater than one, the co-infection equilibrium point may exist. The co-infection equilibrium is found to be locally stable whenever it exists. The TB-only and HIV-only equilibria are locally asymptotically stable under some restriction on parameters. We present numerical simulation results to support the analytical findings. We observe that screening with proper counseling of HIV infectives results in a significant reduction of the number of individuals progressing to HIV. Additionally, the screening of TB reduces the infection prevalence of TB disease. The results reported in this paper clearly indicate that proper screening and counseling can check the spread of HIV and TB diseases and effective control strategies can be formulated around 'screening with proper counseling'.

  11. Estimating dynamic transmission model parameters for seasonal influenza by fitting to age and season-specific influenza-like illness incidence.

    PubMed

    Goeyvaerts, Nele; Willem, Lander; Van Kerckhove, Kim; Vandendijck, Yannick; Hanquet, Germaine; Beutels, Philippe; Hens, Niel

    2015-12-01

    Dynamic transmission models are essential to design and evaluate control strategies for airborne infections. Our objective was to develop a dynamic transmission model for seasonal influenza allowing to evaluate the impact of vaccinating specific age groups on the incidence of infection, disease and mortality. Projections based on such models heavily rely on assumed 'input' parameter values. In previous seasonal influenza models, these parameter values were commonly chosen ad hoc, ignoring between-season variability and without formal model validation or sensitivity analyses. We propose to directly estimate the parameters by fitting the model to age-specific influenza-like illness (ILI) incidence data over multiple influenza seasons. We used a weighted least squares (WLS) criterion to assess model fit and applied our method to Belgian ILI data over six influenza seasons. After exploring parameter importance using symbolic regression, we evaluated a set of candidate models of differing complexity according to the number of season-specific parameters. The transmission parameters (average R0, seasonal amplitude and timing of the seasonal peak), waning rates and the scale factor used for WLS optimization, influenced the fit to the observed ILI incidence the most. Our results demonstrate the importance of between-season variability in influenza transmission and our estimates are in line with the classification of influenza seasons according to intensity and vaccine matching.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Estimating the efficacy of interventions to prevent mother-to-child transmission of human immunodeficiency virus in breastfeeding populations: comparing statistical methods

    PubMed Central

    Alioum, Ahmadou; Cortina-Borja, Mario; Dabis, François; Dequae-Merchadou, Laurence; Haverkamp, Geert; Hughes, James; Karon, John; Leroy, Valeriane; Newell, Marie-Louise; Richardson, Barbra A; Van Weert, Liesbeth; Weverling, Gerrit-Jan; Group, Ghent

    2003-01-01

    Postnatal transmission of human immunodeficiency virus infection through breastfeeding complicates evaluating the efficacy of interventions aimed to reduce mother-to-child transmission risk. Results from trials in Africa evaluating either peripartum antiretroviral therapy or refraining from breastfeeding show an estimated long-term efficacy at 15–24 months of age between 25 and 50 percent. Differences in statistical methods, duration of follow-up, and age at weaning hinder direct comparison between trials. The authors recently outlined theoretically preferred statistical methods for evaluating interventions aimed to reduce risk of mother-to-child transmission of human immunodeficiency virus. When multiple test results and/or supplementary information is available, the more sophisticated methods account for the fact that exact age at infection is unknown, that risk for infection ends at weaning, or that censoring due to death may be informative. The authors apply these methods to four scenarios, using data from four randomized trials carried out in Africa between 1995 and 2000. The authors’ findings suggest that, to estimate the cumulative proportion infected at age 6 weeks, a standard Kaplan-Meier approach is likely to give valid results. For estimation of this proportion at age 18 months, more sophisticated methods, such as the extension of the Kaplan-Meier procedure to interval-censored data and competing risks, would be preferred. PMID:12965885

  17. 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

  18. Novel Mycobacterium tuberculosis complex pathogen, M. mungi.

    PubMed

    Alexander, Kathleen A; Laver, Pete N; Michel, Anita L; Williams, Mark; van Helden, Paul D; Warren, Robin M; Gey van Pittius, Nicolaas C

    2010-08-01

    Seven outbreaks involving increasing numbers of banded mongoose troops and high death rates have been documented. We identified a Mycobacterium tuberculosis complex pathogen, M. mungi sp. nov., as the causative agent among banded mongooses that live near humans in Chobe District, Botswana. Host spectrum and transmission dynamics remain unknown.

  19. 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

  20. Tuberculosis: Medico-Legal Aspects

    PubMed Central

    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

  1. Whole-Genome Sequencing of Mycobacterium tuberculosis Provides Insight into the Evolution and Genetic Composition of Drug-Resistant Tuberculosis in Belarus

    PubMed Central

    Wollenberg, Kurt R.; Desjardins, Christopher A.; Zalutskaya, Aksana; Slodovnikova, Vervara; Oler, Andrew J.; Quiñones, Mariam; Abeel, Thomas; Chapman, Sinead B.; Tartakovsky, Michael; Gabrielian, Andrei; Hoffner, Sven; Skrahin, Aliaksandr; Birren, Bruce W.; Rosenthal, Alexander

    2016-01-01

    ABSTRACT The emergence and spread of drug-resistant Mycobacterium tuberculosis (DR-TB) are critical global health issues. Eastern Europe has some of the highest incidences of DR-TB, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. To better understand the genetic composition and evolution of MDR- and XDR-TB in the region, we sequenced and analyzed the genomes of 138 M. tuberculosis isolates from 97 patients sampled between 2010 and 2013 in Minsk, Belarus. MDR and XDR-TB isolates were significantly more likely to belong to the Beijing lineage than to the Euro-American lineage, and known resistance-conferring loci accounted for the majority of phenotypic resistance to first- and second-line drugs in MDR and XDR-TB. Using a phylogenomic approach, we estimated that the majority of MDR-TB was due to the recent transmission of already-resistant M. tuberculosis strains rather than repeated de novo evolution of resistance within patients, while XDR-TB was acquired through both routes. Longitudinal sampling of M. tuberculosis from 34 patients with treatment failure showed that most strains persisted genetically unchanged during treatment or acquired resistance to fluoroquinolones. HIV+ patients were significantly more likely to have multiple infections over time than HIV− patients, highlighting a specific need for careful infection control in these patients. These data provide a better understanding of the genomic composition, transmission, and evolution of MDR- and XDR-TB in Belarus and will enable improved diagnostics, treatment protocols, and prognostic decision-making. PMID:27903602

  2. Whole-Genome Sequencing of Mycobacterium tuberculosis Provides Insight into the Evolution and Genetic Composition of Drug-Resistant Tuberculosis in Belarus.

    PubMed

    Wollenberg, Kurt R; Desjardins, Christopher A; Zalutskaya, Aksana; Slodovnikova, Vervara; Oler, Andrew J; Quiñones, Mariam; Abeel, Thomas; Chapman, Sinead B; Tartakovsky, Michael; Gabrielian, Andrei; Hoffner, Sven; Skrahin, Aliaksandr; Birren, Bruce W; Rosenthal, Alexander; Skrahina, Alena; Earl, Ashlee M

    2017-02-01

    The emergence and spread of drug-resistant Mycobacterium tuberculosis (DR-TB) are critical global health issues. Eastern Europe has some of the highest incidences of DR-TB, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. To better understand the genetic composition and evolution of MDR- and XDR-TB in the region, we sequenced and analyzed the genomes of 138 M. tuberculosis isolates from 97 patients sampled between 2010 and 2013 in Minsk, Belarus. MDR and XDR-TB isolates were significantly more likely to belong to the Beijing lineage than to the Euro-American lineage, and known resistance-conferring loci accounted for the majority of phenotypic resistance to first- and second-line drugs in MDR and XDR-TB. Using a phylogenomic approach, we estimated that the majority of MDR-TB was due to the recent transmission of already-resistant M. tuberculosis strains rather than repeated de novo evolution of resistance within patients, while XDR-TB was acquired through both routes. Longitudinal sampling of M. tuberculosis from 34 patients with treatment failure showed that most strains persisted genetically unchanged during treatment or acquired resistance to fluoroquinolones. HIV+ patients were significantly more likely to have multiple infections over time than HIV- patients, highlighting a specific need for careful infection control in these patients. These data provide a better understanding of the genomic composition, transmission, and evolution of MDR- and XDR-TB in Belarus and will enable improved diagnostics, treatment protocols, and prognostic decision-making.

  3. Interface Control Document for the EMPACT Module that Estimates Electric Power Transmission System Response to EMP-Caused Damage

    SciTech Connect

    Werley, Kenneth Alan; Mccown, Andrew William

    2016-06-26

    The EPREP code is designed to evaluate the effects of an Electro-Magnetic Pulse (EMP) on the electric power transmission system. The EPREP code embodies an umbrella framework that allows a user to set up analysis conditions and to examine analysis results. The code links to three major physics/engineering modules. The first module describes the EM wave in space and time. The second module evaluates the damage caused by the wave on specific electric power (EP) transmission system components. The third module evaluates the consequence of the damaged network on its (reduced) ability to provide electric power to meet demand. This third module is the focus of the present paper. The EMPACT code serves as the third module. The EMPACT name denotes EMP effects on Alternating Current Transmission systems. The EMPACT algorithms compute electric power transmission network flow solutions under severely damaged network conditions. Initial solutions are often characterized by unacceptible network conditions including line overloads and bad voltages. The EMPACT code contains algorithms to adjust optimally network parameters to eliminate network problems while minimizing outages. System adjustments include automatically adjusting control equipment (generator V control, variable transformers, and variable shunts), as well as non-automatic control of generator power settings and minimal load shedding. The goal is to evaluate the minimal loss of customer load under equilibrium (steady-state) conditions during peak demand.

  4. Permutations of time and place in tuberculosis.

    PubMed

    Elkington, Paul T; Friedland, Jon S

    2015-11-01

    Tuberculosis remains a global health pandemic. The current depiction of the Mycobacterium tuberculosis life cycle proposes that airborne bacilli are inhaled and phagocytosed by alveolar macrophages, resulting in the formation of a granuloma that ruptures into the airways to reinitiate the infectious cycle. However, this widely proposed model overlooks the fact, established 100 years ago, that the initial site of M tuberculosis implantation is in the lower zones of the lungs, whereas infectious cavitary pulmonary disease develops at the lung apices. The immunological events at these two pulmonary locations are different--cavitation only occurs in the apices and not in the bases. Yet the current conceptual model of tuberculosis renders the immunology of these two temporally and spatially separated events identical. One key consequence is that prevention of primary childhood tuberculosis at the lung bases is regarded as adequate immunological protection, but extensive evidence shows that greater immunity could predispose to immunopathology and transmission at the lung apex. A much greater understanding of time and place in the immunopathological mechanisms underlying human tuberculosis is needed before further pre-exposure vaccination trials can be done.

  5. Did ice-age bovids spread tuberculosis?

    NASA Astrophysics Data System (ADS)

    Rothschild, Bruce M.; Martin, Larry D.

    2006-11-01

    Pathognomonic metacarpal undermining is a skeletal pathology that has been associated with Mycobacterium tuberculosis in bovids. Postcranial artiodactyl, perissodactyl, and carnivore skeletons were examined in major university and museum collections of North America and Europe for evidence of this and other pathology potentially attributable to tuberculosis. Among nonproboscidean mammals from pre-Holocene North America, bone lesions indicative of tuberculosis were restricted to immigrant bovids from Eurasia. No bone lesions compatible with diagnosis of tuberculosis were found in large samples of other pre-Holocene (164 Oligocene, 397 Miocene, and 1,041 Plio Pleistocene) North American mammals, including 114 antilocaprids. Given the unchanged frequency of bovid tubercular disease during the Pleistocene, it appears that most did not die from the disease but actually reached an accommodation with it (as did the mastodon) (Rothschild and Laub 2006). Thus, they were sufficiently long-lived to assure greater spread of the disease. The relationships of the proboscidean examples need further study, but present evidence suggests a Holarctic spread of tuberculosis during the Pleistocene, with bovids acting as vectors. While the role of other animals in the transmission of tuberculosis could be considered, the unique accommodation achieved by bovids and mastodons makes them the likely “culprits” in its spread.

  6. Tuberculosis among long term hospital residents: report of a recent outbreak.

    PubMed

    Taylor, D R; Allison, G; Phillips, D E

    1991-10-09

    Following the diagnosis of a case of miliary tuberculosis in a ward of 30 psychogeriatric patients, a further seven patients required treatment for active tuberculosis, and an additional four received prophylactic therapy. Tuberculosis contributed significantly to the deaths of three patients during the outbreak. This report highlights the particular risks of both reactivation and primary tuberculosis among geriatric patients receiving long term residential care. Late diagnosis contributed to the extent of the outbreak. Previous studies indicate that occult transmission of tuberculosis is relatively common in this group. An active policy of screening and prophylactic treatment is advised.

  7. Tuberculosis epidemiology in India: a review.

    PubMed

    Chadha, V K

    2005-10-01

    High prevalence and incidence of disease and a high rate of transmission of infection characterise the tuberculosis (TB) situation in India. Disease surveys conducted in different parts of the country since the 1950s have reported prevalences of smear-positive pulmonary TB (PTB) of 0.6-7.6 per 1000 population, culture-positive TB of 1.7-9.8 and culture and/or smear-positive TB of 1.8-12.7. The incidence of smear-positive PTB has been observed in the range of 1.0-1.6/1000 and that of culture-positive PTB 1.0-2.5/1000 in the limited number of studies carried out. The annual risk of tuberculous infection (ARTI) had been estimated at 1-2% for most of the tuberculin surveys carried out in different areas over different time periods. During a nationwide study in 2000-2003, the average ARTI in the country was estimated at 1.5%. An increasing trend has been observed in human immunodeficiency virus (HIV) seropositivity among TB cases, which has been found to vary between 0.4% and 28.8% in different studies conducted mostly at tertiary health care centres. The proportion of new cases with multidrug resistance (MDR) was relatively low, at 0.5-5.3%. However, the proportion of MDR cases among previously treated cases varied between 8% and 67%.

  8. Multiple estimates of transmissibility for the 2009 influenza pandemic based on influenza-like-illness data from small US military populations.

    PubMed

    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 ([Formula: see text], 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.

  9. 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

  10. A soft computing scheme incorporating ANN and MOV energy in fault detection, classification and distance estimation of EHV transmission line with FSC.

    PubMed

    Khadke, Piyush; Patne, Nita; Singh, Arvind; Shinde, Gulab

    2016-01-01

    In this article, a novel and accurate scheme for fault detection, classification and fault distance estimation for a fixed series compensated transmission line is proposed. The proposed scheme is based on artificial neural network (ANN) and metal oxide varistor (MOV) energy, employing Levenberg-Marquardt training algorithm. The novelty of this scheme is the use of MOV energy signals of fixed series capacitors (FSC) as input to train the ANN. Such approach has never been used in any earlier fault analysis algorithms in the last few decades. Proposed scheme uses only single end measurement energy signals of MOV in all the 3 phases over one cycle duration from the occurrence of a fault. Thereafter, these MOV energy signals are fed as input to ANN for fault distance estimation. Feasibility and reliability of the proposed scheme have been evaluated for all ten types of fault in test power system model at different fault inception angles over numerous fault locations. Real transmission system parameters of 3-phase 400 kV Wardha-Aurangabad transmission line (400 km) with 40 % FSC at Power Grid Wardha Substation, India is considered for this research. Extensive simulation experiments show that the proposed scheme provides quite accurate results which demonstrate complete protection scheme with high accuracy, simplicity and robustness.

  11. Tuberculosis Data and Statistics

    MedlinePlus

    ... Search The CDC Cancel Submit Search The CDC Tuberculosis (TB) Note: Javascript is disabled or is not ... message, please visit this page: About CDC.gov . Tuberculosis Basic TB Facts How TB Spreads Latent TB ...

  12. 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. ...

  13. Tuberculosis Treatment and Pregnancy

    MedlinePlus

    ... Search The CDC Cancel Submit Search The CDC Tuberculosis (TB) Note: Javascript is disabled or is not ... message, please visit this page: About CDC.gov . Tuberculosis Basic TB Facts How TB Spreads Latent TB ...

  14. Impaired Cytokine but Enhanced Cytotoxic Marker Expression in Mycobacterium tuberculosis-Induced CD8+ T Cells in Individuals With Type 2 Diabetes and Latent Mycobacterium tuberculosis Infection.

    PubMed

    Kumar, Nathella Pavan; Moideen, Kadar; George, Parakkal Jovvian; Dolla, Chandrakumar; Kumaran, Paul; Babu, Subash

    2016-03-01

    Type 2 diabetes mellitus (DM) is a risk factor for tuberculosis among individuals with latent Mycobacterium tuberculosis infection. To explore the influence of DM on CD8(+) T-cell responses during latent M. tuberculosis infection, we estimated the cytokine and cytotoxic marker expression pattern in individuals with latent M. tuberculosis infection with DM and those with latent M. tuberculosis infection without DM. Among individuals with latent M. tuberculosis infection, those with DM had diminished frequencies of CD8(+) T-helper type 1 (Th1), Th2, and Th17 cells following stimulation by M. tuberculosis antigen and enhanced frequencies of CD8(+) T cells expressing cytotoxic markers, compared with those without DM. Thus, our results suggest that coincident DM modulates CD8(+) T-cell function during latent M. tuberculosis infection.

  15. [Tuberculosis epidemiology in Mayotte Island].

    PubMed

    Woessner, J; Receveur, M C; Malvy, D; Taytard, A

    2008-10-01

    Mayotte is a French territory island, part of the Comoros Archipelago in the Indian Ocean with 200,000 inhabitants. The tuberculosis control program started in 1976, although available epidemiological data remains incomplete. We conducted a retrospective hospital-based survey in 202 outpatients and hospital medical records from the Hospital Centre of the main city to contribute to the epidemiological evaluation of tuberculosis patterns. The tuberculosis frequency remains unchanged since 2000. It affects a young population partly coming from the other neighbouring Comoro Islands (69%) with illegal immigrate status (53% in 2004). The systematic diagnostic screening efficiency of the condition appears marginal. Pulmonary involvement is the most frequent clinical manifestation (78%), although severe extrapulmonary manifestations are not exceptional. Co-infection with HIV and multi resistance to antituberculosis agents are not frequent. Up to 60% of cases have been proven to be bacteriologically linked. The notification rate remains critically low with an estimate of 39% of notifications to the local sanitary authorities in charge of secondary cases screening. The case coverage seems limited both by low socio-economical status and poor health facility accessibility The loss of follow up is dramatically high, 41% on the overall period, and up to 51% in 2004. Our results make mandatory the reinforcement of a tuberculosis survey and control involvement within the context of this French territory. Screening, care and follow up are to be implemented particularly for vulnerable and precarious groups and for patients.

  16. 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.

  17. Global Tuberculosis Report 2016

    MedlinePlus

    ... WHO Language عربي 中文 English Français Русский Español Tuberculosis (TB) Menu Tuberculosis The End TB Strategy Areas ... data News, events and features About us Global tuberculosis report 2016 WHO has published a global TB ...

  18. Standardised PCR-based molecular epidemiology of tuberculosis.

    PubMed

    Allix-Béguec, C; Supply, P; Wanlin, M; Bifani, P; Fauville-Dufaux, M

    2008-05-01

    A population-based molecular epidemiology investigation has been undertaken to evaluate tuberculosis transmission and control in the Brussels-Capital Region (Belgium). All tuberculosis cases reported from January 2003 to December 2004 were investigated. In total, 536 Mycobacterium tuberculosis isolates (89% of culture-positive samples) were genotyped by the newly standardised 24 loci-based mycobacterial interspersed repetitive unit-variable number tandem-repeat typing, spoligotyping and IS6110 fingerprinting. Of all the patients, 30% were grouped based on strain clusters, suggesting a transmission index of 20%. An unsuspected outbreak entailing > or = 23 patients was evidenced by molecular typing analysis and confirmed by contact tracing. Foreign-born status accounted for 79% of the studied patients, including 37.9% illegal immigrants and asylum seekers. Among foreign-born patients, asylum seekers and illegal immigrants were significantly less abundant in strain clusters than settled residents. Tuberculosis in the Brussels-Capital Region is a bi-faceted problem, comprising both persisting recent transmission and "imported diseases". Molecular epidemiology based on real-time genotyping techniques has proven invaluable in better understanding tuberculosis transmission. However, it will most efficiently contribute to tuberculosis control when implemented in an integrated public health system.

  19. 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.

  20. Tuberculosis knowledge among New York City injection drug users.

    PubMed Central

    Wolfe, H; Marmor, M; Maslansky, R; Nichols, S; Simberkoff, M; Des Jarlais, D; Moss, A

    1995-01-01

    Structured interviews measuring tuberculosis knowledge were administered to 494 New York City injection drug users, 31% of whom reported a history of having a reactive tuberculin skin test. Medical records review of a subsample confirmed the validity of self-reported data. Most respondents understood the mechanisms of tuberculosis transmission. Three fourths of the subjects did not fully understand the distinction between a reactive skin test and active tuberculosis, but those who reported a history of skin test reactivity were twice as likely to understand this distinction. Forty percent of subjects did not understand the importance of medication adherence. Misunderstandings, based on a recent lack of tuberculosis education, may contribute to the fear and confusion that interfere with efforts to control tuberculosis. PMID:7604926

  1. [Four cases of pulmonary tuberculosis among deep-sea fishermen].

    PubMed

    Ono, Hidemaro; Murakami, Reiko; Tsuruwaka, Mia; Suzuki, Yoshihiko

    2003-06-01

    Pulmonary tuberculosis among deep-sea fishermen was reported. Four pulmonary tuberculosis cases among fishing boat members engaged in deep-sea fishing were registered at the Kesennuma Health Center during three years period from 2000 to 2002. Crew engaging in deep-sea fishing live together in a narrow cabin with inadequate airconditioning for a long period of time, about 1 year. It is difficult to consult with a medical institution in an open sea. If a tuberculosis patient breaks out in a boat, the risk of transmission of tuberculosis to other members is high. In boats of all four cases in this report, about 30 to 70 percent of crew were Indonesian. Indonesia is one of the high burden countries of tuberculosis in the world. The Japanese fishing boat members have received the medical checkup every year. Indonesians have also received the pre-employment medical checkup, however, the improvement in the quality of this medical checkup is required.

  2. [Diagnosed tuberculosis using specific DNA probe hybridization methods].

    PubMed

    Furuta, Itaru; Yamazumi, Toshiaki

    2002-11-01

    In Japan, reported cases of tuberculosis had declined nearly every year until 1995. However, in 1997 newly recorded cases began increasing for the first time in more than 38 years. Recent studies using DNA fingerprinting show that person- to person transmission may account for as many as one-third of new cases of tuberculosis in citizen populations. Nucleic acid hybridization methods using specific DNA probes can specifically identify M. tuberculosis and other mycobacterial species. Rapid nucleic acid amplification techniques such as polymerase chain reaction methods allow direct identification of M. tuberculosis in clinical specimens. Is 6110 has been exploited extensively as a clonal marker in molecular epidemiology studies of tuberculosis. The emergence of resistance to antituberculosis drugs is a relevant matter worldwide. A recent genotypic method allows earlier detection of RFP-resistant and INH-resistant stains using probes for mutation in rpoB and in katG.

  3. Miliary tuberculosis

    PubMed Central

    Mert, Ali; Arslan, Ferhat; Kuyucu, Tülin; Koç, Emine Nur; Yılmaz, Mesut; Turan, Demet; Altın, Sedat; Pehlivanoglu, Filiz; Sengoz, Gonul; Yıldız, Dilek; Dokmetas, Ilyas; Komur, Suheyla; Kurtaran, Behice; Demirdal, Tuna; Erdem, Hüseyin A.; Sipahi, Oguz Resat; Batirel, Ayse; Parlak, Emine; Tekin, Recep; Tunçcan, Özlem Güzel; Balkan, Ilker Inanc; Hayran, Osman; Ceylan, Bahadır

    2017-01-01

    Abstract The aim of this study was to determine the clinical features, and outcome of the patients with miliary tuberculosis (TB). We retrospectively evaluated 263 patients (142 male, 121 female, mean age: 44 years, range: 16–89 years) with miliary TB. Criteria for the diagnosis of miliary TB were at least one of the followings in the presence of clinical presentation suggestive of miliary TB such as prolonged fever, night sweats, anorexia, weight loss: radiologic criterion and pathological criterion and/or microbiological criterion; pathological criterion and/or microbiological criterion. The miliary pattern was seen in 88% of the patients. Predisposing factors were found in 41% of the patients. Most frequent clinical features and laboratory findings were fever (100%), fatigue (91%), anorexia (85%), weight loss (66%), hepatomegaly (20%), splenomegaly (19%), choroid tubercules (8%), anemia (86%), pancytopenia (12%), and accelerated erythrocyte sedimentation rate (89%). Tuberculin skin test was positive in 29% of cases. Fifty percent of the patients met the criteria for fever of unknown origin. Acid-fast bacilli were demonstrated in 41% of patients (81/195), and cultures for Mycobacterium tuberculosis were positive in 51% (148/292) of tested specimens (predominantly sputum, CSF, and bronchial lavage). Blood cultures were positive in 20% (19/97). Granulomas in tissue samples of liver, lung, and bone marrow were present in 100% (21/21), 95% (18/19), and 82% (23/28), respectively. A total of 223 patients (85%) were given a quadruple anti-TB treatment. Forty-four (17%) patients died within 1 year after diagnosis established. Age, serum albumin, presence of military pattern, presence of mental changes, and hemoglobin concentration were found as independent predictors of mortality. Fever resolved within first 21 days in the majority (90%) of the cases. Miliary infiltrates on chest X-ray should raise the possibility of miliary TB especially in countries where TB is

  4. Cutaneous tuberculosis in children.

    PubMed

    Sethuraman, Gomathy; Ramesh, Venkatesh

    2013-01-01

    Cutaneous tuberculosis is a rare form of extrapulmonary tuberculosis that accounts for 1% to 2% of cases. Childhood skin tuberculosis represents 18% to 82% of all cutaneous tuberculosis cases. Scrofuloderma and lupus vulgaris are the two most common clinical forms in children. An increase in the number of tuberculids, especially lichen scrofulosorum, has been observed in the last several years. Cutaneous tuberculosis in children can be severe and have a protracted course. Multiplicity of lesions and multifocal disseminated involvement in scrofuloderma and lupus vulgaris is common. Scrofuloderma progressing to gummatous lesions (scrofulous gumma) is mostly described in children. Morbidities and deformities are more severe in children.

  5. [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.

  6. 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.

  7. Long-term temporal trends and estimated transmission rates for Mycobacterium bovis infection in an undisturbed high-density badger (Meles meles) population.

    PubMed

    Delahay, R J; Walker, N; Smith, G C; Smith, G S; Wilkinson, D; Clifton-Hadley, R S; Cheeseman, C L; Tomlinson, A J; Chambers, M A

    2013-07-01

    We describe epidemiological trends in Mycobacterium bovis infection in an undisturbed wild badger (Meles meles) population. Data were derived from the capture, clinical sampling and serological testing of 1803 badgers over 9945 capture events spanning 24 years. Incidence and prevalence increased over time, exhibiting no simple relationship with host density. Potential explanations are presented for a marked increase in the frequency of positive serological test results. Transmission rates (R0) estimated from empirical data were consistent with modelled estimates and robust to changes in test sensitivity and the spatial extent of the population at risk. The risk of a positive culture or serological test result increased with badger age, and varied seasonally. Evidence consistent with progressive disease was found in cubs. This study demonstrates the value of long-term data and the repeated application of imperfect diagnostic tests as indices of infection to reveal epidemiological trends in M. bovis infection in badgers.

  8. 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

  9. Comparison of QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for diagnosis of latent tuberculosis in haemodialysis (HD) patients: a meta-analysis of κ estimates.

    PubMed

    Ayubi, E; Doosti-Irani, A; Sanjari Moghaddam, A; Khazaei, S; Mansori, K; Safiri, S; Sani, M; Mostafavi, E

    2017-03-02

    Diagnosis of latent tuberculosis infection (LTBI) is a concern in haemodialysis (HD) patients. Many studies have compared QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for detecting LTBI and reported the κ statistic of agreement between QFT-GIT and TST in HD patients. The present study aimed to systematically review this literature and conduct meta-analysis of individual studies that estimated the κ between QFT-GIT with TST among HD patients. All relevant published studies that were available as full-text were obtained by searching Medline (1950), Web of Sciences (1945), Scopus (1973) through May 2016. The κ was re-estimated from the individual studies and pooled using random effect meta-analysis. Subgroup analysis and meta-regression were applied to evaluate the effect of Bacillus Calmette-Guérin (BCG) vaccination, TST cut-off points, quality of studies, sample size and age on variation of κ estimate. Eight studies involving 901 HD patients were included in meta-analysis. The pooled κ estimate was 0·28 (I 2 = 18·4%, P = 0·239, 95% confidence intervals 0·22-0·34). The discordance of TST-/QFT-GIT+ was more than TST+/QFT-GIT-. History of BCG vaccination, TST cut-off points and age are related to variation of κ estimates. TST and QFT-GIT are not comparable in detecting LTBI in HD patients. The higher TST-/QFT-GIT+ ratio compared with TST+/QFT-GIT- ratio, may indicate the superiority of QFT-GIT over TST for detection LTBI in HD patients.

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

    PubMed

    Wang, Han; Du, Wencai; Xu, Lingwei

    2016-06-24

    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.

  11. 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

  12. Equilibrating errors: reliable estimation of information transmission rates in biological systems with spectral analysis-based methods.

    PubMed

    Ignatova, Irina; French, Andrew S; Immonen, Esa-Ville; Frolov, Roman; Weckström, Matti

    2014-06-01

    Shannon's seminal approach to estimating information capacity is widely used to quantify information processing by biological systems. However, the Shannon information theory, which is based on power spectrum estimation, necessarily contains two sources of error: time delay bias error and random error. These errors are particularly important for systems with relatively large time delay values and for responses of limited duration, as is often the case in experimental work. The window function type and size chosen, as well as the values of inherent delays cause changes in both the delay bias and random errors, with possibly strong effect on the estimates of system properties. Here, we investigated the properties of these errors using white-noise simulations and analysis of experimental photoreceptor responses to naturalistic and white-noise light contrasts. Photoreceptors were used from several insect species, each characterized by different visual performance, behavior, and ecology. We show that the effect of random error on the spectral estimates of photoreceptor performance (gain, coherence, signal-to-noise ratio, Shannon information rate) is opposite to that of the time delay bias error: the former overestimates information rate, while the latter underestimates it. We propose a new algorithm for reducing the impact of time delay bias error and random error, based on discovering, and then using that size of window, at which the absolute values of these errors are equal and opposite, thus cancelling each other, allowing minimally biased measurement of neural coding.

  13. Understanding tuberculosis epidemiology using structured statistical models.

    PubMed

    Getoor, Lise; Rhee, Jeanne T; Koller, Daphne; Small, Peter

    2004-03-01

    Molecular epidemiological studies can provide novel insights into the transmission of infectious diseases such as tuberculosis. Typically, risk factors for transmission are identified using traditional hypothesis-driven statistical methods such as logistic regression. However, limitations become apparent in these approaches as the scope of these studies expand to include additional epidemiological and bacterial genomic data. Here we examine the use of Bayesian models to analyze tuberculosis epidemiology. We begin by exploring the use of Bayesian networks (BNs) to identify the distribution of tuberculosis patient attributes (including demographic and clinical attributes). Using existing algorithms for constructing BNs from observational data, we learned a BN from data about tuberculosis patients collected in San Francisco from 1991 to 1999. We verified that the resulting probabilistic models did in fact capture known statistical relationships. Next, we examine the use of newly introduced methods for representing and automatically constructing probabilistic models in structured domains. We use statistical relational models (SRMs) to model distributions over relational domains. SRMs are ideally suited to richly structured epidemiological data. We use a data-driven method to construct a statistical relational model directly from data stored in a relational database. The resulting model reveals the relationships between variables in the data and describes their distribution. We applied this procedure to the data on tuberculosis patients in San Francisco from 1991 to 1999, their Mycobacterium tuberculosis strains, and data on contact investigations. The resulting statistical relational model corroborated previously reported findings and revealed several novel associations. These models illustrate the potential for this approach to reveal relationships within richly structured data that may not be apparent using conventional statistical approaches. We show that Bayesian

  14. 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.

  15. 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.

  16. 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

  17. 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.

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

    PubMed

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

    2015-12-05

    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.

  19. Functional, biochemical and 3D studies of Mycobacterium tuberculosis protein peptides for an effective anti-tuberculosis vaccine.

    PubMed

    Ocampo, Marisol; Patarroyo, Manuel A; Vanegas, Magnolia; Alba, Martha P; Patarroyo, Manuel E

    2014-05-01

    Tuberculosis (TB) is an air-born, transmissible disease, having an estimated 9.4 million new TB cases worldwide in 2009. Eventual control of this disease by developing a safe and efficient new vaccine able to detain its spread will have an enormous impact on public health policy. Selecting potential antigens to be included in a multi-epitope, minimal subunit-based, chemically-synthesized vaccine containing the minimum sequences needed for blocking mycobacterial interaction with host cells is a complex task due to the multiple mechanisms involved in M. tuberculosis infection and the mycobacterium's immune evasion mechanisms. Our methodology, described here takes into account a highly robust, specific, sensitive and functional approach to the search for potential epitopes to be included in an anti-TB vaccine; it has been based on identifying short mycobacterial protein fragments using synthetic peptides having high affinity interaction with alveolar epithelial cells (A549) and monocyte-derived macrophages (U937) which are able to block the microorganism's entry to target cells in in vitro assays. This manuscript presents a review of the results obtained with some of the MTB H37Rv proteins studied to date, aimed at using these high activity binding peptides (HABPs) as platforms to be included in a minimal subunit-based, multiepitope, chemically-synthesized, antituberculosis vaccine.

  20. 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

  1. 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

  2. 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, ...

  3. Tuberculosis in the aftermath of the 2010 earthquake in Haiti

    PubMed Central

    Rouzier, Vanessa; Vilbrun, Stalz Charles; Morose, Willy; Collins, Sean E; Joseph, Patrice; Decome, Diessy; Ocheretina, Oksana; Galbaud, Stanislas; Hashiguchi, Lauren; Pierrot, Julma; Pape, Jean William

    2015-01-01

    Abstract Problem In 2010, Haiti sustained a devastating earthquake that crippled the health-care infrastructure in the capital city, Port-au-Prince, and left 1.5 million people homeless. Subsequently, there was an increase in reported tuberculosis in the affected population. Approach We conducted active tuberculosis case finding in a camp for internally displaced persons and a nearby slum. Community health workers screened for tuberculosis at the household level. People with persistent cough were referred to a physician. The National Tuberculosis Program continued its national tuberculosis reporting system. Local setting Even before the earthquake, Haiti had the highest tuberculosis incidence in the Americas. About half of the tuberculosis cases occur in the Port-au-Prince region. Relevant changes The number of reported tuberculosis cases in Haiti has increased after the earthquake, but data are too limited to determine if this is due to an increase in tuberculosis burden or to improved case detection. Compared to previous national estimates (230 per 100 000 population), undiagnosed tuberculosis was threefold higher in a camp for internally displaced persons (693 per 100 000) and fivefold higher in an urban slum (1165 per 100 000). With funding from the World Health Organization (WHO), active case finding is now being done systematically in slums and camps. Lessons learnt Household-level screening for prolonged cough was effective in identifying patients with active tuberculosis in this study. Without accurate data, early detection of rising tuberculosis rates is challenging; data collection should be incorporated into pragmatic disease response programmes. PMID:26170508

  4. 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

  5. Non-pulmonary tuberculosis.

    PubMed

    Carrol, E D; Clark, J E; Cant, A J

    2001-06-01

    Tuberculosis (TB) is a serious disease of global importance, with a rising incidence in the developed world in recent years. Tuberculous lymphadenitis, tuberculous meningitis, osteoarticular tuberculosis and miliary tuberculosis are some of the more well-recognised manifestations of non-pulmonary TB in childhood. The diagnosis of non-pulmonary TB poses a particular challenge for clinicians because of the protean ways in which the disease presents. The omission of tuberculosis from the differential diagnosis of patients with obscure illnesses and the relatively insensitive bacteriological methods for detecting Mycobacterium tuberculosis add to the complexity of the problem. A high index of suspicion is required in order to avoid delays in diagnosis which may influence treatment outcome. The advent of DNA amplification techniques such as the polymerase chain reaction may herald a promising new era in the prompt and accurate management of extrapulmonary tuberculosis.

  6. Childhood tuberculosis and malnutrition.

    PubMed

    Jaganath, Devan; Mupere, Ezekiel

    2012-12-15

    Despite the burden of both malnutrition and tuberculosis in children worldwide, there are few studies on the mechanisms that underlie this relationship. From available research, it appears that malnutrition is a predictor of tuberculosis disease and is associated with worse outcomes. This is supported through several lines of evidence, including the role of vitamin D receptor genotypes, malnutrition's effects on immune development, respiratory infections among malnourished children, and limited work specifically on pediatric tuberculosis and malnutrition. Nutritional supplementation has yet to suggest significant benefits on the course of tuberculosis in children. There is a critical need for research on childhood tuberculosis, specifically on how nutritional status affects the risk and progression of tuberculosis and whether nutritional supplementation improves clinical outcomes or prevents disease.

  7. Clonality and micro-diversity of a nationwide spreading genotype of Mycobacterium tuberculosis in Japan.

    PubMed

    Wada, Takayuki; Iwamoto, Tomotada; Tamaru, Aki; Seto, Junji; Ahiko, Tadayuki; Yamamoto, Kaori; Hase, Atushi; Maeda, Shinji; Yamamoto, Taro

    2015-01-01

    Mycobacterium tuberculosis transmission routes can be estimated from genotypic analysis of clinical isolates from patients. In Japan, still a middle-incidence country of TB, a unique genotype strain designated as 'M-strain' has been isolated nationwide recently. To ascertain the history of the wide spread of the strain, 10 clinical isolates from different areas were subjected to genome-wide analysis based on deep sequencers. Results show that all isolates possessed common mutations to those of referential strains. The greatest number of accumulated single nucleotide variants (SNVs) from the oldest coalescence was 13 nucleotides, indicating high clonality of these isolates. When an SNV common to the isolates was used as a surrogate marker of the clone, authentic clonal isolates with variation in a reliable subset of variable number of tandem repeat (VNTR) genotyping method can be selected successfully from clinical isolates populations of M. tuberculosis. When the authentic clones can also be assigned to sub-clonal groups by SNVs derived from the genomic comparison, they are classifiable into three sub-clonal groups with a bias of geographical origins. Feedback from genomic analysis of clinical isolates of M. tuberculosis to genotypic markers will be an efficient strategy for the big data in various settings for public health actions against TB.

  8. Tuberculosis versus vasculitis.

    PubMed

    Baig, Zahid Farooq; Raja, Khalid Mahmood; Abbas, Fahad

    2014-01-01

    Vasculitis (Wegeners Granulomatosis and Microscopic Polyangiitis) and Tuberculosis share many features including constitutional symptoms and respiratory tract involvement. The presence of kidney involvement with new onset azotaemia and active urine sediment support the diagnosis of vasculitis. We describe two cases that were diagnosed to be suffering from tuberculosis and placed on anti-tuberculosis therapy. On further workup they were found to be suffering from pauci- immune glomerulonephritis and recovered well with treatment.

  9. Abdominal involvement in tuberculosis.

    PubMed

    Neyman, Edward G; Georgiades, Christos S; Fishman, Elliot K

    2002-10-01

    Rising incidence of disseminated and extrapulmonary tuberculosis (TB), especially in immunocompromised hosts and patients with multi-drug-resistant tuberculosis, has resulted in an increase of unusual clinical and radiographic presentations of TB. With CT being a common part of emergency room (ER) evaluation of abdominal pain, it is imperative that radiologists be able to recognize abdominal presentations of TB. We discuss and illustrate typical and less common CT manifestations of tuberculosis in the abdomen to help ER radiologists in this task.

  10. 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

  11. Cost-effectiveness of tuberculosis evaluation and treatment of newly-arrived immigrants

    PubMed Central

    Porco, Travis C; Lewis, Bryan; Marseille, Elliot; Grinsdale, Jennifer; Flood, Jennifer M; Royce, Sarah E

    2006-01-01

    Background Immigrants to the U.S. are required to undergo overseas screening for tuberculosis (TB), but the value of evaluation and treatment following entry to the U.S. is not well understood. We determined the cost-effectiveness of domestic follow-up of immigrants identified as tuberculosis suspects through overseas screening. Methods Using a stochastic simulation for tuberculosis reactivation, transmission, and follow-up for a hypothetical cohort of 1000 individuals, we calculated the incremental cost-effectiveness of follow-up and evaluation interventions. We utilized published literature, California Reports of Verified Cases of Tuberculosis (RVCTs), demographic estimates from the California Department of Finance, Medicare reimbursement, and Medi-Cal reimbursement rates. Our target population was legal immigrants to the United States, our time horizon is twenty years, and our perspective was that of all domestic health-care payers. We examined the intervention to offer latent tuberculosis therapy to infected individuals, to increase the yield of domestic evaluation, and to increase the starting and completion rates of LTBI therapy with INH (isoniazid). Our outcome measures were the number of cases averted, the number of deaths averted, the incremental dollar cost (year 2004), and the number of quality-adjusted life-years saved. Results Domestic follow-up of B-notification patients, including LTBI treatment for latently infected individuals, is highly cost-effective, and at times, cost-saving. B-notification follow-up in California would reduce the number of new tuberculosis cases by about 6–26 per year (out of a total of approximately 3000). Sensitivity analysis revealed that domestic follow-up remains cost-effective when the hepatitis rates due to INH therapy are over fifteen times our best estimates, when at least 0.4 percent of patients have active disease and when hospitalization of cases detected through domestic follow-up is no less likely than

  12. Updates on Knowledge, Attitude and Preventive Practices on Tuberculosis among Healthcare Workers

    PubMed Central

    Wahab, Farhanah Abd; Abdullah, Sarimah; Abdullah, Jafri Malin; Jaafar, Hasnan; Noor, Siti Suraiya Md; Mohammad, Wan Mohd Zahiruddin Wan; Yusoff, Abdul Aziz Mohamed; Tharakan, John; Bhaskar, Shalini; Sangu, Muthuraju; Mahmood, Mohd Shah; Kassim, Fauziah; Rafia, Md. Hanip; Haspani, Mohammed Safari Mohammed; Alias, Azmi; Pando, Rogelio Hernández

    2016-01-01

    Ranking as the most communicable disease killer worldwide, tuberculosis, has accounted with a total of 9.6 million new tuberculosis cases with 1.5 million tuberculosis-related deaths reported globally in 2014. Tuberculosis has remain as an occupational hazard for healthcare workers since 1920s and due to several tuberculosis outbreaks in healthcare settings in the early 1990s, the concern about the transmission to both patients and healthcare workers has been raised. Healthcare workers have two to three folds greater the risk of active tuberculosis than the general population. Several studies on knowledge, attitude and practices on tuberculosis among healthcare workers worldwide have revealed that majority of the participated healthcare workers had good knowledge on tuberculosis. Most of the healthcare workers from South India and South Africa also reported to have positive attitude whereas a study in Thailand reported that most of the healthcare providers have negative attitude towards tuberculosis patients. Nevertheless, majority of the healthcare workers have low level of practice on tuberculosis prevention. An improved communication between healthcare workers and the patients as well as their families is the key to better therapeutic outcomes with good knowledge, attitude and preventive practice towards tuberculosis. PMID:28090176

  13. 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

  14. New Mycobacterium tuberculosis Complex Sublineage, Brazzaville, Congo

    PubMed Central

    Malm, Sven; Linguissi, Laure S. Ghoma; Tekwu, Emmanuel M.; Vouvoungui, Jeannhey C.; Kohl, Thomas A.; Beckert, Patrick; Sidibe, Anissa; Rüsch-Gerdes, Sabine; Madzou-Laboum, Igor K.; Kwedi, Sylvie; Penlap Beng, Véronique; Frank, Matthias; Ntoumi, Francine

    2017-01-01

    Tuberculosis is a leading cause of illness and death in Congo. No data are available about the population structure and transmission dynamics of the Mycobacterium tuberculosis complex strains prevalent in this central Africa country. On the basis of single-nucleotide polymorphisms detected by whole-genome sequencing, we phylogenetically characterized 74 MTBC isolates from Brazzaville, the capital of Congo. The diversity of the study population was high; most strains belonged to the Euro-American lineage, which split into Latin American Mediterranean, Uganda I, Uganda II, Haarlem, X type, and a new dominant sublineage named Congo type (n = 26). Thirty strains were grouped in 5 clusters (each within 12 single-nucleotide polymorphisms), from which 23 belonged to the Congo type. High cluster rates and low genomic diversity indicate recent emergence and transmission of the Congo type, a new Euro-American sublineage of MTBC. PMID:28221129

  15. Web tools for molecular epidemiology of tuberculosis.

    PubMed

    Shabbeer, Amina; Ozcaglar, Cagri; Yener, Bülent; Bennett, Kristin P

    2012-06-01

    In this study we explore publicly available web tools designed to use molecular epidemiological data to extract information that can be employed for the effective tracking and control of tuberculosis (TB). The application of molecular methods for the epidemiology of TB complement traditional approaches used in public health. DNA fingerprinting methods are now routinely employed in TB surveillance programs and are primarily used to detect recent transmissions and in outbreak investigations. Here we present web tools that facilitate systematic analysis of Mycobacterium tuberculosis complex (MTBC) genotype information and provide a view of the genetic diversity in the MTBC population. These tools help answer questions about the characteristics of MTBC strains, such as their pathogenicity, virulence, immunogenicity, transmissibility, drug-resistance profiles and host-pathogen associativity. They provide an integrated platform for researchers to use molecular epidemiological data to address current challenges in the understanding of TB dynamics and the characteristics of MTBC.

  16. 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

  17. Tuberculosis eradication versus control.

    PubMed

    Schito, Marco; Hanna, Debra; Zumla, Alimuddin

    2017-03-01

    According to the World Health Organization (WHO), 10.4 million people died of tuberculosis (TB) in 2015, and the disease is now the number one cause of death from a preventable infectious disease worldwide. A bold vision is needed from global leaders to end the TB epidemic and plans to this end have been proposed. However enthusiasm must be matched by tangible and achievable goals based on the science and available funding. In order to reach the target and goals set by the WHO End TB Strategy, the challenges for TB eradication need to be addressed. In order to achieve the targets, several areas need to be bolstered, including the requirement to better identify and treat existing drug-susceptible cases and diagnose all the drug-resistant forms of the disease. Although treatment is available for most TB patients, stock-outs and other delays are problematic in some settings, resulting in ongoing transmission, especially for the drug-resistant forms of the disease. Despite the fact that a majority of multidrug-resistant cases are linked to treatment, the cure rate is only 50%, which highlights the need for safer, shorter, and more efficacious drug regimens that are more tolerable to patients. Prospects for a more efficacious vaccine are limited, with no correlates of protection identified; thus the availability of a vaccine by 2025 is highly improbable. Support for instituting infection control methods should be prioritized to subvert transmission while patients seek treatment and care. Finally, more adequate financial mechanisms should be instituted to reduce patient expenditures and support national TB programs. Moreover, funding to support basic science, drug development, clinical trials, vaccine development, diagnostics, and implementation research needs to be secured in order to reduce global TB incidence in the future.

  18. 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.

  19. 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

  20. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    NASA Astrophysics Data System (ADS)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2016-11-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  1. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    NASA Astrophysics Data System (ADS)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2017-03-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  2. 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.

  3. 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

  4. [The global importance of tuberculosis].

    PubMed

    Rieder, Hans L

    2011-07-01

    In the western industrialized world tuberculosis has receded from its peak with an annual mortality of 1 % some 150 to 250 years ago to currently 10 to 20 new cases annually per 100,000 population. The introduction of chemotherapy in the 1950s reduced case fatality from some 70 % to a small fraction. Nowadays, the indigenous elderly and immigrants from high-prevalence countries contribute most of tuberculosis morbidity in the industrialized world. In contrast, tuberculosis remains a major public health problem in most resource-constrained countries and has substantially increased in sub-Saharan Africa as a result of the impact of HIV infection. The World Health Organization estimates that each year over 9 million new cases emerge in the world. Because of weak infrastructures low-income countries continue to experience shortages in the drug supply, facilitating the emergence of strains resistant to first-line drugs which are difficult or impossible to treat. The primordial task for the international community is to assist in strengthening the necessary infrastructures and to help ensuring that patients have unrestricted and uninterrupted access to antituberculosis medications and antiretroviral drugs.

  5. Zoonotic tuberculosis in human beings caused by Mycobacterium bovis-a call for action.

    PubMed

    Olea-Popelka, Francisco; Muwonge, Adrian; Perera, Alejandro; Dean, Anna S; Mumford, Elizabeth; Erlacher-Vindel, Elisabeth; Forcella, Simona; Silk, Benjamin J; Ditiu, Lucica; El Idrissi, Ahmed; Raviglione, Mario; Cosivi, Ottorino; LoBue, Philip; Fujiwara, Paula I

    2017-01-01

    Mycobacterium tuberculosis is recognised as the primary cause of human tuberculosis worldwide. However, substantial evidence suggests that the burden of Mycobacterium bovis, the cause of bovine tuberculosis, might be underestimated in human beings as the cause of zoonotic tuberculosis. In 2013, results from a systematic review and meta-analysis of global zoonotic tuberculosis showed that the same challenges and concerns expressed 15 years ago remain valid. These challenges faced by people with zoonotic tuberculosis might not be proportional to the scientific attention and resources allocated in recent years to other diseases. The burden of zoonotic tuberculosis in people needs important reassessment, especially in areas where bovine tuberculosis is endemic and where people live in conditions that favour direct contact with infected animals or animal products. As countries move towards detecting the 3 million tuberculosis cases estimated to be missed annually, and in view of WHO's end TB strategy endorsed by the health authorities of WHO Member States in 2014 to achieve a world free of tuberculosis by 2035, we call on all tuberculosis stakeholders to act to accurately diagnose and treat tuberculosis caused by M bovis in human beings.

  6. Declaring a tuberculosis outbreak over with genomic epidemiology

    PubMed Central

    Hatherell, Hollie-Ann; Didelot, Xavier; Pollock, Sue L.; Tang, Patrick; Crisan, Anamaria; Johnston, James C.; Colijn, Caroline

    2016-01-01

    We report an updated method for inferring the time at which an infectious disease was transmitted between persons from a time-labelled pathogen genome phylogeny. We applied the method to 48 Mycobacterium tuberculosis genomes as part of a real-time public health outbreak investigation, demonstrating that although active tuberculosis (TB) cases were diagnosed through 2013, no transmission events took place beyond mid-2012. Subsequent cases were the result of progression from latent TB infection to active disease, and not recent transmission. This evolutionary genomic approach was used to declare the outbreak over in January 2015. PMID:28348853

  7. Global Epidemiology of Tuberculosis

    PubMed Central

    Glaziou, Philippe; Sismanidis, Charalambos; Floyd, Katherine; Raviglione, Mario

    2015-01-01

    Despite the availability of effective chemotherapy, tuberculosis (TB) killed 1.3 million people in 2012. Alongside HIV, it remains a top cause of death from an infectious disease. Global targets for reductions in the epidemiological burden of TB have been set for 2015 and 2050 within the context of the Millennium Development Goals (MDGs) and by the Stop TB Partnership. Achieving these targets is the focus of national and international efforts in TB control, and showing whether or not they are achieved is of major importance to guide future and sustainable investments. This article provides a short overview of sources of data to estimate TB disease burden; presents estimates of TB incidence, prevalence, and mortality in 2012 and an assessment of progress toward the 2015 targets for reductions in these indicators based on trends since 1990 and projections up to 2015; analyzes trends in TB notifications and in the implementation of the Stop TB Strategy; and considers prospects for elimination of TB after 2015. PMID:25359550

  8. 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.

  9. 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.

  10. [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.

  11. [Tuberculosis in Switzerland].

    PubMed

    Shang, H; Desgrandchamps, D

    1995-10-03

    In Switzerland, in 1992, 957 persons suffered from tuberculosis; 52.3% were Swiss, 47.7% foreigners. Most of the swiss TB patients were more than 65 years old, whereas the foreigners generally were young patients originating from countries with high TB-infection rates. Asylum seekers had much higher TB-case rates (131 cases per 100,000) than other foreigners (27 cases per 100,000) or Swiss (9 cases per 100,000). Special refuge reception centers have been set up in Switzerland, in charge of tuberculosis screening procedures in this high-risk group on arrival to this country. Although HIV and AIDS patients bear a much higher risk of developing tuberculosis once infected, the HIV epidemic did not lead to an increase of tuberculosis in Switzerland so far, since young Swiss are rarely infected with tuberculosis. HIV-infected, drug addicts, homeless persons and alcoholics run a higher risk of contracting tuberculosis only when congregating with a person suffering from active tuberculosis not yet diagnosed or improperly treated. In order to maintain low levels of tuberculosis in Switzerland DOT (directly observed therapy) must be implemented in all patients with uncertain compliance, especially as cultural and social backgrounds become increasingly complex.

  12. Tuberculosis of the knee

    PubMed Central

    Lidder, Surjit; Lang, Kathryn; Haroon, Mallick; Shahidi, Mitra; El-Guindi, Magdi

    2009-01-01

    Extrapulmonary manifestations of tuberculosis are reported in less than one in five cases with the knee affected in 8% after the spine and hip. We report a case of isolated highly erosive tuberculosis of the knee presenting in a previously fit Vietnamese woman. The difficulties of diagnosis, modalities of chemotherapeutic management, and surgical treatment are discussed. PMID:21808686

  13. "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…

  14. Tuberculosis in Somalia.

    PubMed

    Turpie, I D

    2008-05-01

    This is a description of a tuberculosis treatment programme in a country at war where security and the absence of order pose problems to health care delivery. It is also a description of an epidemic of tuberculosis where treatment and diagnosis are difficult and the methods used have changed little in many years. More international pressure is needed.

  15. 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

  16. A dynamic model of tuberculosis epidemiology for Singapore.

    PubMed

    Goh, E H; Fam, K L

    1981-01-01

    An epidemiological model was used to estimate the size of the tuberculosis problem in Singapore from 1975 to 2025. It was shown that even without any control activities after 1979 there would be a reduction of the tuberculosis indices in the country. If the present control programme was pursued unchanged, a reduction of the tuberculosis problem by 10.0% and 14.5% would be expected in 2000 and 2025 respectively. Tuberculosis would be expected to remain a major public health problem over the next fifty years. In Singapore's context increased case finding and treatment of bacteriologically positive cases of tuberculosis would be the most effective ways of further reducing the tuberculosis problem over the next fifty years. Practical methods of implementing this were suggested. Reduced BCG coverage of infants was not expected to increase the tuberculosis problem to any significant extent over this period. Treatment relapse rates were shown not to be a sensitive variable that would affect the tuberculosis problem in Singapore.

  17. Bovine tuberculosis at the human-livestock-wildlife interface: is it a public health problem in Tanzania? A review.

    PubMed

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

    2012-06-20

    Despite the apparent public health concern about Bovine tuberculosis (BTB) in Tanzania, little has been done regarding the zoonotic importance of the disease and raising awareness of the community to prevent the disease. Bovine tuberculosis is a potential zoonotic disease that can infect a variety of hosts, including humans. The presence of multiple hosts including wild animals, inefficient diagnostic techniques, absence of defined national controls and eradication programs could impede the control of bovine TB. In Tanzania, the diagnosis of Mycobacterium bovis in animals is mostly carried out by tuberculin skin testing, meat inspection in abattoirs and only rarely using bacteriological techniques. The estimated prevalence of BTB in animals in Tanzania varies and ranges across regions from 0.2% to 13.3%, which is likely to be an underestimate if not confirmed by bacteriology or molecular techniques. Mycobacterium bovis has been detected and isolated from different animal species and has been recovered in 10% of apparently healthy wildebeest that did not show lesions at post-mortem. The transmission of the disease from animals to humans can occur directly through the aerosol route and indirectly by consumption of raw milk. This poses an emerging disease threat in the current era of HIV confection in Tanzania and elsewhere. Mycobacterium bovis is one of the causative agents of human extra pulmonary tuberculosis. In Tanzania there was a significant increase (116.6%) of extrapulmonary cases reported between 1995 and 2009, suggesting the possibility of widespread M. bovis and Mycobacterium tuberculosis infection due to general rise of Human Immunodeficiency virus (HIV). This paper aims to review the potential health and economic impact of bovine tuberculosis and challenges to its control in order to safeguard human and animal population in Tanzania.

  18. 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

  19. Genitourinary manifestations of tuberculosis.

    PubMed

    Wise, Gilbert J; Marella, Venkata K

    2003-02-01

    By the 1980s, the availability of antituberculosis chemotherapy reduced the incidence and prevalence of tuberculosis. Changing patterns of population emigration and the development of large pools of immune-compromised individuals reversed the downward trend of tuberculosis. The incidence of genitourinary tuberculosis has remained constant. The manifestations of GU TB can be variable and cause a variety of clinical patterns that mimic other diseases. Adrenal insufficiency, renal disease, obstructive uropathy, and chronic cystitis are not uncommon with TB. The patient with TB may have genital disease that simulates STD or scrotal tumors. Infertility can be caused by GU tuberculosis. Awareness of environmental factors and patient history should alert the urologist to the wide array of clinical findings in the genitourinary system that can be caused by tuberculosis.

  20. Tuberculosis: current trends in diagnosis and treatment.

    PubMed

    Bello, A K; Njoku, C H; Njoku, A K

    2005-12-01

    Among communicable diseases, tuberculosis (TB) is the second leading cause of death worldwide, killing nearly 2 million people each year. It is estimated that about one-third of the world population are infected with TB (2 billion people) and about 10% of this figure will progress to disease state. Most cases are in the less-developed countries of the world. Tuberculosis incidence has been on the increase in Africa, mainly as a result of the burden of HIV infection. Definitive diagnosis of tuberculosis remains based on culture for Mycobacterium tuberculosis, but rapid diagnosis of infectious tuberculosis by simple sputum smear for acid fast bacilli remains an important tool, as more rapid molecular techniques are being developed. Treatment with several drugs for 6 months or more can cure more than 95% of patients. Direct observation of treatment, a component of the recommended five-element DOTS strategy, is judged to be the standard of care by most authorities. Currently only a third of cases worldwide are treated using this approach. There may be need to modify the treatment modalities especially with the choice of drugs and duration of therapy when TB infection occurs in special situation like pregnancy, liver disease, renal failure or even in coexistence with HlV/AIDS or the drug resistant state.

  1. 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.

  2. The effect of diabetes and undernutrition trends on reaching 2035 global tuberculosis targets.

    PubMed

    Odone, Anna; Houben, Rein M G J; White, Richard G; Lönnroth, Knut

    2014-09-01

    To achieve the post-2015 global tuberculosis target of 90% reduction in tuberculosis incidence by 2035, the present rate of decline must accelerate. Among factors that hinder tuberculosis control, malnutrition and diabetes are key challenges. We review available data to describe the complex relationship between tuberculosis, diabetes, and nutritional status. Additionally, we review past trends, present burden, and available future global projections for diabetes, overweight and obesity, as well as undernutrition and food insecurity. Using a mathematical model, we estimate the potential effect of these factors on tuberculosis burden up to 2035. Great potential exists for reduction of worldwide tuberculosis burden by combination of improved prevention and care of diabetes with reduction of undernutrition. To achieve this combination will require joint efforts and strong cross-programme links, enabling synergistic effects of public health policies that promote good nutrition and optimum clinical care for tuberculosis and diabetes.

  3. Diversity of DNA Fingerprints of Mycobacterium tuberculosis Isolates in the United States

    PubMed Central

    Yang, Zhenhua; Barnes, Peter F.; Chaves, Fernando; Eisenach, Kathleen D.; Weis, Stephen E.; Bates, Joseph H.; Cave, M. Donald

    1998-01-01

    To investigate the diversity of IS6110 fingerprints of Mycobacterium tuberculosis isolates in the United States and to determine if matching IS6110 fingerprints represent recent interstate tuberculosis transmission, we performed restriction fragment length polymorphism analysis of M. tuberculosis isolates from 1,326 patients in three geographically separated states. Seven hundred ninety-five different IS6110 fingerprint patterns were generated, and pattern diversity was similar in each state. Ninety-six percent of the fingerprint patterns were observed in only one state, demonstrating that most IS6110 fingerprint patterns are confined to a single geographic location. Of the IS6110 fingerprint patterns that were shared by isolates from more than one state, most isolates with 1 to 5 IS6110 copies were separable by pTBN12 fingerprinting whereas those with >15 copies were not. One high-copy-number M. tuberculosis strain had identical IS6110 and pTBN12 fingerprints and included 57 isolates from three states. Epidemiological data demonstrated significant recent transmission of tuberculosis within each city but not among the states. This suggests that identical fingerprints of isolates from geographically separate locations most likely reflect interstate tuberculosis transmission in the past, with subsequent intrastate spread of disease. Further evaluation of M. tuberculosis strains that cause outbreaks in different geographic locations will provide insight into the epidemiological and bacteriological factors that facilitate the spread of tuberculosis. PMID:9542926

  4. Mycobacterium tuberculosis Isolates from Single Outpatient Clinic in Panama City Exhibit Wide Genetic Diversity

    PubMed Central

    Sambrano, Dilcia; Correa, Ricardo; Almengor, Pedro; Domínguez, Amada; Vega, Silvio; Goodridge, Amador

    2014-01-01

    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

  5. 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.

  6. Data for action: collection and use of local data to end tuberculosis.

    PubMed

    Theron, Grant; Jenkins, Helen E; Cobelens, Frank; Abubakar, Ibrahim; Khan, Aamir J; Cohen, Ted; Dowdy, David W

    2015-12-05

    Accelerating progress in the fight against tuberculosis will require a drastic shift from a strategy focused on control to one focused on elimination. Successful disease elimination campaigns are characterised by locally tailored responses that are informed by appropriate data. To develop such a response to tuberculosis, we suggest a three-step process that includes improved collection and use of existing programmatic data, collection of additional data (eg, geographic information, drug resistance, and risk factors) to inform tailored responses, and targeted collection of novel data (eg, sequencing data, targeted surveys, and contact investigations) to improve understanding of tuberculosis transmission dynamics. Development of a locally targeted response for tuberculosis will require substantial investment to reconfigure existing systems, coupled with additional empirical data to evaluate the effectiveness of specific approaches. Without adoption of an elimination strategy that uses local data to target hotspots of transmission, ambitious targets to end tuberculosis will almost certainly remain unmet.

  7. 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

  8. Dentistry and tuberculosis in the 1900s.

    PubMed

    Riben, P D; Epstein, J B; Mathias, R G

    1995-06-01

    The number of new cases--or incidence--of tuberculosis is increasing in nearly every region of the world. A number of forces have resulted in the increased incidence of TB in developed countries, including the HIV epidemic, homelessness, and emigration from highly endemic regions. Although the number of new cases in Canada is relatively constant, the TB experience in the United States serves as a reminder that this situation could change rapidly. The appearance of multidrug-resistant tuberculosis has added to the urgency of situation. The basic methods of preventing TB transmission include preventing the release of the organism into the air, removing the organism from the air, and preventing the inhalation of the organism. Identifying and appropriately treating every person with active tuberculosis is an extremely important component of the control strategy; adequate ventilation, filtering air, and ultraviolet germicidal irradiation are methods used to remove the organism from the air; and masks and other personal protective devices, such as high-efficiency particulate air filters (HEPA), have been suggested as a means of preventing inhalation of the organism. In addition, identifying new TB infections and using chemoprophylaxis often prevents infection from progressing to active disease. Given the route by which tuberculosis is transmitted, it is necessary for both dentists and allied dental personnel to be aware of the risks they may face in day-to-day practice, and the means by which they can protect themselves and their patients.

  9. 68 FR 75767 - Occupational Exposure to Tuberculosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2003-12-31

    ... Tuberculosis; Proposed Rule; Termination of Rulemaking Respiratory Protection for M. Tuberculosis; Final Rule... Exposure to Tuberculosis AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION... Occupational Exposure to Tuberculosis (TB). Because of a broad range of Federal and community initiatives,...

  10. Do high rates of empirical treatment undermine the potential effect of new diagnostic tests for tuberculosis in high-burden settings?

    PubMed

    Theron, Grant; Peter, Jonny; Dowdy, David; Langley, Ivor; Squire, S Bertel; Dheda, Keertan

    2014-06-01

    In tuberculosis-endemic settings, patients are often treated empirically, meaning that they are placed on treatment based on clinical symptoms or tests that do not provide a microbiological diagnosis (eg, chest radiography). New tests for tuberculosis, such as the Xpert MTB/RIF assay (Cepheid, Sunnyvale, CA, USA), are being implemented at substantial cost. To inform policy and rationally drive implementation, data are needed for how these tests affect morbidity, mortality, transmission, and population-level tuberculosis burden. If people diagnosed by use of new diagnostics would have received empirical treatment a few days later anyway, then the incremental benefit might be small. Will new diagnostics substantially improve outcomes and disease burden, or simply displace empirical treatment? Will the extent and accuracy of empirical treatment change with the introduction of a new test? In this Personal View, we review emerging data for how empirical treatment is frequently same-day, and might still be the predominant form of treatment in high-burden settings, even after Xpert implementation; and how Xpert might displace so-called true-positive, rather than false-positive, empirical treatment. We suggest types of studies needed to accurately assess the effect of new tuberculosis tests and the role of empirical treatment in real-world settings. Until such questions can be addressed, and empirical treatment is appropriately characterised, we postulate that the estimated population-level effect of new tests such as Xpert might be substantially overestimated.

  11. 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.

  12. Molecular characterisation of Mycobacterium tuberculosis isolates in the First National Survey of Anti-tuberculosis Drug Resistance from Venezuela

    PubMed Central

    Aristimuño, Liselotte; Armengol, Raimond; Cebollada, Alberto; España, Mercedes; Guilarte, Alexis; Lafoz, Carmen; Lezcano, María A; Revillo, María J; Martín, Carlos; Ramírez, Carmen; Rastogi, Nalin; Rojas, Janet; de Salas, Albina Vázques; Sola, Christophe; Samper, Sofía

    2006-01-01

    Background Molecular typing of Mycobacterium tuberculosis strains has become a valuable tool in the epidemiology of tuberculosis (TB) by allowing detection of outbreaks, tracking of epidemics, identification of genotypes and transmission events among patients who would have remained undetected by conventional contact investigation. This is the first genetic biodiversity study of M. tuberculosis in Venezuela. Thus, we investigated the genetic patterns of strains isolated in the first survey of anti-tuberculosis drug-resistance realised as part of the Global Project of Anti-tuberculosis Drug Resistance Surveillance (WHO/IUATLD). Results Clinical isolates (670/873) were genotyped by spoligotyping. The results were compared with the international spoligotyping database (SpolDB4). Multidrug resistant (MDR) strains (14/18) were also analysed by IS6110-RFLP assays, and resistance to isoniazid and rifampicin was characterised. Spoligotyping grouped 82% (548/670) of the strains into 59 clusters. Twenty new spoligotypes (SITs) specific to Venezuela were identified. Eight new inter-regional clusters were created. The Beijing genotype was not found. The genetic network shows that the Latin American and Mediterranean family constitutes the backbone of the genetic TB population-structure in Venezuela, responsible of >60% of total TB cases studied. MDR was 0.5% in never treated patients and 13.5% in previously treated patients. Mutations in rpoB gene and katG genes were detected in 64% and 43% of the MDR strains, respectively. Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis. Conclusion This study gives a first overview of the M. tuberculosis strains circulating in Venezuela during the first survey of anti-tuberculosis drug-resistance. It may aid in the creation of a national database that will be a valuable support for further studies. PMID:17032442

  13. 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.

  14. Effectiveness of contact investigations for tuberculosis control in Arkansas

    PubMed Central

    Guzzetta, Giorgio; Ajelli, Marco; Yang, Zhenhua; Mukasa, Leonard N.; Patil, Naveen; Bates, Joseph H.; Kirschner, Denise E.; Merler, Stefano

    2015-01-01

    Comprehensive assessment of the effectiveness of contact investigations for tuberculosis (TB) control is still lacking. In this study, we use a computational model, calibrated against notification data from Arkansas during the period 2001–2011, that reproduces independent data on key features of TB transmission and epidemiology. The model estimates that the Arkansas contact investigations program has avoided 18.6% (12.1–25.9%) of TB cases and 23.7% (16.4–30.6%) of TB deaths that would have occurred during 2001–2014 if passive diagnosis alone were implemented. If contacts of sputum smear-negative cases had not been included in the program, the percentage reduction would have been remarkably lower. In addition, we predict that achieving national targets for performance indicators of contact investigation programs has strong potential to further reduce TB transmission and burden. However, contact investigations are expected to have limited effectiveness on avoiding reactivation cases of latent infections over the next 60 years. PMID:26051196

  15. IFNγ Response to Mycobacterium tuberculosis, Risk of Infection and Disease in Household Contacts of Tuberculosis Patients in Colombia

    PubMed Central

    Marín, Nancy D.; Marín, Diana M.; López, Lucelly; Henao, Hanna M.; Martínez, Teresita; Villa, Liliana; Barrera, Luis F.; Ortiz, Blanca L.; Ramírez, María E.; Montes, Carlos J.; Oquendo, María C.; Arango, Lisandra M.; Riaño, Felipe; Aguirre, Carlos; Bustamante, Alberto; Belisle, John T.; Dobos, Karen; Mejía, Gloria I.; Giraldo, Margarita R.; Brennan, Patrick J.; Robledo, Jaime; Arbeláez, María P.; Rojas, Carlos A.; García, Luis F.

    2009-01-01

    Objectives Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNγ produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNγ levels in HHCs correlate with tuberculosis development. Methods A cohort of 2060 HHCs was followed for 2–3 years after exposure to a tuberculosis case. Besides TST, IFNγ responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. Results Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNγ response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNγ responders to CFP-10 (HR 1.82 95% CI 0.79–4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNγ producers was observed (trend Log rank p = 0.007). Discussion CFP-10-induced IFNγ production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high

  16. 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.

  17. [Epidemiology of tuberculosis].

    PubMed

    Mjid, M; Cherif, J; Ben Salah, N; Toujani, S; Ouahchi, Y; Zakhama, H; Louzir, B; Mehiri-Ben Rhouma, N; Beji, M

    2015-01-01

    Tuberculosis is a contagious disease caused by Mycobacterium tuberculosis. It represents, according to World Health Organization (WHO), one of the most leading causes of death worldwide. With nearly 8 million new cases each year and more than 1 million deaths per year, tuberculosis is still a public health problem. Despite of the decrease in incidence, morbidity and mortality remain important partially due to co-infection with human immunodeficiency virus and emergence of resistant bacilli. All WHO regions are not uniformly affected by TB. Africa's region has the highest rates of morbidity and mortality. The epidemiological situation is also worrying in Eastern European countries where the proportion of drug-resistant tuberculosis is increasing. These regional disparities emphasize to develop screening, diagnosis and monitoring to the most vulnerable populations. In this context, the Stop TB program, developed by the WHO and its partner's, aims to reduce the burden of disease in accordance with the global targets set for 2015.

  18. 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

  19. 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

  20. [Tuberculosis of the prostate].

    PubMed

    Streltsova, O S; Krupin, V N; Yunusova, K E; Mamonov, M V

    2016-12-01

    Genitourinary tract is the second most common site where extrapulmonary tuberculosis (TB) occurs. Genitourinary TB is notable for a latent clinical course and difficult diagnosis. The paper presents clinical observations of two patients treated in a urology department of a general public hospital. One of them was diagnosed with tuberculosis of the prostate, MTB+. In the other, TB of the prostate was suspected based on pathologic assessment of the surgical specimen after surgery for prostate cancer.

  1. Current approaches to tuberculosis in the United States.

    PubMed

    Gordin, Fred M; Masur, Henry

    2012-07-18

    Tuberculosis is a major threat to global health, infecting a third of the world's population. In the United States, however, control of tuberculosis has been increasingly successful. Only 3.2% of the US population is estimated to have latent tuberculosis and there are only 11,000 cases annually of active disease. More than half the cases in this country occur in individuals born outside the United States. Human immunodeficiency virus coinfection is not a major factor in the United States, since only approximately 10% of cases are coinfected. Drug resistance is also uncommon in this country. Because the United States has more resources for the diagnosis, therapy, and public health control of tuberculosis than many regions of the world, and because many hospitals have more cases of clinically significant nontuberculous mycobacteria than tuberculosis, the management approaches to tuberculosis need to be quite different in this country than in other regions. The resurgence in interest in developing new tools and the investment in public health infrastructure will hopefully be sustained in the United States so that the effect of tuberculosis on the US population will continue to diminish, and these new tools and approaches can be adapted to both high and low prevalence areas to meet the global challenge.

  2. Molecular diversity of Mycobacterium tuberculosis isolates from patients with tuberculosis in Honduras

    PubMed Central

    2010-01-01

    Background Tuberculosis persists as a public health problem in Honduras. A better knowledge of the molecular characteristics of Mycobacterium tuberculosis strains will contribute to understand the transmission dynamics of the disease within the country. The aim of this study was to provide an insight of the genetic biodiversity of M. tuberculosis clinical isolates collected in Honduras between 1994 and 2002. Genotyping was performed using spoligotyping and RFLP. The spoligotypes obtained were compared with the SITVIT2 proprietary database of the Pasteur Institute of Guadeloupe. Results Spoligotyping grouped 84% of the isolates into 27 clusters (2 to 43 strains per cluster). Of the 44 shared international types (SITs) identified among the Honduran stains, 8 SITs were newly identified either within the present study or after match with an orphan type previously identified in the SITVIT2 database. In addition, 16 patterns corresponded to orphan, previously unreported isolates. The Latin American Mediterranean (LAM) lineage was the most common in this study; 55% of the strains belonged to this family. Other genotypes found were Haarlem (16%), T (16%), X-clade (6%), Unknown signature (5%) and S (1%). Only one Beijing strain was identified (0.5%). We observed a high degree of diversity after characterizing the 43 isolates belonging to the main spoligotyping cluster (SIT 33, LAM3) with IS6110-RFLP. A total of 35 different RFLP-fingerprints were detected, of which 6 patterns corresponded to the same number of clusters comprising 14 strains. Conclusions The findings obtained in this study show that tuberculosis transmission in Honduras is due to modern M. tuberculosis lineages with high level of biodiversity. PMID:20678242

  3. 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

  4. 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

  5. Genetic Lineages of Mycobacterium tuberculosis Isolates in Isfahan, Iran.

    PubMed

    Riyahi Zaniani, Fatemeh; Moghim, Sharareh; Mirhendi, Hossein; Ghasemian Safaei, Hajieh; Fazeli, Hossein; Salehi, Mahshid; Nasr Esfahani, Bahram

    2017-01-01

    In this study, we aimed to identify the genetic lineages of Mycobacterium tuberculosis isolates in Isfahan via the mycobacterial interspersed repetitive-unit-variable number tandem repeat typing method based on 15 loci. Forty-nine M. tuberculosis isolates were collected between 2013 and 2015 from Tuberculosis patients in Mollahadi Sabzevari Tuberculosis Center in Isfahan. All isolates were typed by 15-locus MIRU-VNTR typing. The highest percentage of isolates, 44.89 % (22/49), belonged to the Euro-American lineage, while the frequencies of the East-African-Indian, East-Asian, and Indo-Oceanic lineages were 28.57 % (14/49), 24.4 % (12/49), and 2.04 % (1/49), respectively. Among the 22 isolates of the Euro-American lineage, those belonging to the NEW-1 sub-lineage were most prevalent (24.4 %). Approximately, the same proportion of isolates belonging to the Delhi/CAS, Beijing, and NEW-1 sub-lineages were identified in Iranian and Afghan immigrant patients. The Delhi/CAS and Beijing sub-lineage isolates were prevalent among patients who had been previously treated for TB. Results showed that all of the 49 MIRU-VNTR patterns were unique and the clustering rate of the 15-locus MIRU-VNTR was 0.0 (minimum recent transmission). The results of this study show that the lineages of M. tuberculosis isolates in Isfahan are similar to those reported in the Eastern Mediterranean region (indicative of the epidemiological relationship between the countries in the region). The low clustering rate in our results reveals that transmission of tuberculosis in Isfahan is, in most cases, a reactivation of previous tuberculosis infection and the role of recently transmitted disease is minor.

  6. Accidental infection of veterinary personnel with Mycobacterium tuberculosis at necropsy: a case study.

    PubMed

    Posthaus, H; Bodmer, T; Alves, L; Oevermann, A; Schiller, I; Rhodes, S G; Zimmerli, S

    2011-05-05

    Mycobacterium tuberculosis is the main cause of human tuberculosis. Infection in companion animals is mainly acquired from close contact to a diseased human patient and hence rarely diagnosed in countries with low tuberculosis incidence rates. Therefore the general awareness of the disease might be low. Here we report the potential risk of infection for veterinary personnel with M. tuberculosis during the clinical and pathological examination of a dog with unexpected disseminated tuberculosis. The dog had presented with symptoms of a central nervous system disease; rapid deterioration prevented a complete clinical workup, however. Post-mortem examination revealed systemic mycobacteriosis, and M. tuberculosis was identified by PCR amplification of DNA extracts from paraffin-embedded tissue sections and spoligotyping. Contact investigations among the owners and veterinary personnel using an IFN-γ release assay indicated that the index dog did not infect humans during its lifetime. Serological and IFN-γ release assay results of one of two cats in direct contact with the index dog, however, suggested that transmission of M. tuberculosis might have occurred. Importantly, all three pathologists performing the necropsy on the dog tested positive. Accidental infection was most likely due to inhalation of M. tuberculosis containing aerosols created by using an electric saw to open the brain cavity. As a consequence routine necropsy procedures have been adapted and a disease surveillance program, including tuberculosis, has been initiated. Our results highlight the importance of disease awareness and timely diagnosis of zoonotic infectious agents in optimizing work safety for veterinary personnel.

  7. [Primary infection and pulmonary tuberculosis].

    PubMed

    Toujani, S; Ben Salah, N; Cherif, J; Mjid, M; Ouahchy, Y; Zakhama, H; Daghfous, J; Beji, M; Mehiri-Ben Rhouma, N; Louzir, B

    2015-01-01

    Tuberculosis is a major public health problem worldwide. Indeed, a third of the world population is infected with Mycobacterium tuberculosis and more than 8 million new cases of tuberculosis each year. Pulmonary tuberculosis is the most common location. Its diagnosis is difficult and often established with a delay causing a spread of infection. The diagnosis of tuberculosis infection is mainly based on immunological tests represented by the tuberculin skin test and detection of gamma interferon, while the diagnosis of pulmonary tuberculosis is suspected on epidemiological context, lasting general and respiratory symptoms, contrasting usually with normal lung examination, and a chest radiography showing suggestive lesions. The radioclinical feature may be atypical in patients with extreme ages and in case of immunodeficiency. Confirmation of tuberculosis is bacteriological. Conventional bacteriological methods remain the reference. Innovative tests using the technique of molecular biology have improved the diagnosis of tuberculosis in terms of sensitivity and especially speed. However, those techniques are of limited use.

  8. Tuberculosis in seals caused by a novel member of the Mycobacterium tuberculosis complex: Mycobacterium pinnipedii sp. nov.

    PubMed

    Cousins, Debby V; Bastida, Ricardo; Cataldi, Angel; Quse, Viviana; Redrobe, Sharon; Dow, Sue; Duignan, Padraig; Murray, Alan; Dupont, Christine; Ahmed, Niyaz; Collins, Des M; Butler, W Ray; Dawson, David; Rodríguez, Diego; Loureiro, Julio; Romano, Maria Isabel; Alito, A; Zumarraga, M; Bernardelli, Amelia

    2003-09-01

    A comparison of Mycobacterium tuberculosis complex isolates from seals (pinnipeds) in Australia, Argentina, Uruguay, Great Britain and New Zealand was undertaken to determine their relationships to each other and their taxonomic position within the complex. Isolates from 30 cases of tuberculosis in six species of pinniped and seven related isolates were compared to representative and standard strains of the M. tuberculosis complex. The seal isolates could be distinguished from other members of the M. tuberculosis complex, including the recently defined 'Mycobacterium canettii' and 'Mycobacterium caprae', on the basis of host preference and phenotypic and genetic tests. Pinnipeds appear to be the natural host for this 'seal bacillus', although the organism is also pathogenic in guinea pigs, rabbits, humans, Brazilian tapir (Tapirus terrestris) and, possibly, cattle. Infection caused by the seal bacillus is predominantly associated with granulomatous lesions in the peripheral lymph nodes, lungs, pleura, spleen and peritoneum. Cases of disseminated disease have been found. As with other members of the M. tuberculosis complex, aerosols are the most likely route of transmission. The name Mycobacterium pinnipedii sp. nov. is proposed for this novel member of the M. tuberculosis complex (the type strain is 6482(T)=ATCC BAA-688(T)=NCTC 13288(T)).

  9. A dynamic model of bovine tuberculosis spread and control in Great Britain.

    PubMed

    Brooks-Pollock, Ellen; Roberts, Gareth O; Keeling, Matt J

    2014-07-10

    Bovine tuberculosis (TB) is one of the most complex, persistent and controversial problems facing the British cattle industry, costing the country an estimated £100 million per year. The low sensitivity of the standard diagnostic test leads to considerable ambiguity in determining the main transmission routes of infection, which exacerbates the continuing scientific debate. In turn this uncertainty fuels the fierce public and political disputes on the necessity of controlling badgers to limit the spread of infection. Here we present a dynamic stochastic spatial model for bovine TB in Great Britain that combines within-farm and between-farm transmission. At the farm scale the model incorporates stochastic transmission of infection, maintenance of infection in the environment and a testing protocol that mimics historical government policy. Between-farm transmission has a short-range environmental component and is explicitly driven by movements of individual cattle between farms, as recorded in the Cattle Tracing System. The resultant model replicates the observed annual increase of infection over time as well as the spread of infection into new areas. Given that our model is mechanistic, it can ascribe transmission pathways to each new case; the majority of newly detected cases involve several transmission routes with moving infected cattle, reinfection from an environmental reservoir and poor sensitivity of the diagnostic test all having substantive roles. This underpins our findings on the implications of control measures. Very few of the control options tested have the potential to reverse the observed annual increase, with only intensive strategies such as whole-herd culling or additional national testing proving highly effective, whereas controls focused on a single transmission route are unlikely to be highly effective.

  10. Screening for tuberculosis and testing for human immunodeficiency virus in Zambian prisons

    PubMed Central

    Maggard, Katie R; Hatwiinda, Sisa; Harris, Jennifer B; Phiri, Winifreda; Krüüner, Annika; Kaunda, Kaunda; Topp, Stephanie M; Kapata, Nathan; Ayles, Helen; Chileshe, Chisela; Henostroza, German

    2015-01-01

    Abstract Objective To improve the Zambia Prisons Service’s implementation of tuberculosis screening and human immunodeficiency virus (HIV) testing. Methods For both tuberculosis and HIV, we implemented mass screening of inmates and community-based screening of those residing in encampments adjacent to prisons. We also established routine systems – with inmates as peer educators – for the screening of newly entered or symptomatic inmates. We improved infection control measures, increased diagnostic capacity and promoted awareness of tuberculosis in Zambia’s prisons. Findings In a period of 9 months, we screened 7638 individuals and diagnosed 409 new patients with tuberculosis. We tested 4879 individuals for HIV and diagnosed 564 cases of infection. An additional 625 individuals had previously been found to be HIV-positive. Including those already on tuberculosis treatment at the time of screening, the prevalence of tuberculosis recorded in the prisons and adjacent encampments – 6.4% (6428/100 000) – is 18 times the national prevalence estimate of 0.35%. Overall, 22.9% of the inmates and 13.8% of the encampment residents were HIV-positive. Conclusion Both tuberculosis and HIV infection are common within Zambian prisons. We enhanced tuberculosis screening and improved the detection of tuberculosis and HIV in this setting. Our observations should be useful in the development of prison-based programmes for tuberculosis and HIV elsewhere. PMID:25883402

  11. 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

  12. Tuberculosis Comorbidity with Communicable and Noncommunicable Diseases.

    PubMed

    Bates, Matthew; Marais, Ben J; Zumla, Alimuddin

    2015-02-06

    The 18th WHO Global Tuberculosis Annual Report indicates that there were an estimated 8.6 million incident cases of tuberculosis (TB) in 2012, which included 2.9 million women and 530,000 children. TB caused 1.3 million deaths including 320,000 human immunodeficiency virus (HIV)-infected people; three-quarters of deaths occurred in Africa and Southeast Asia. With one-third of the world's population latently infected with Mycobacterium tuberculosis (Mtb), active TB disease is primarily associated with a break down in immune surveillance. This explains the strong link between active TB disease and other communicable diseases (CDs) or noncommunicable diseases (NCDs) that exert a toll on the immune system. Comorbid NCD risk factors include diabetes, smoking, malnutrition, and chronic lung disease, all of which have increased relentlessly over the past decade in developing countries. The huge overlap between killer infections such as TB, HIV, malaria, and severe viral infections with NCDs, results in a "double burden of disease" in developing countries. The current focus on vertical disease programs fails to recognize comorbidities or to encourage joint management approaches. This review highlights major disease overlaps and discusses the rationale for better integration of tuberculosis care with services for NCDs and other infectious diseases to enhance the overall efficiency of the public health responses.

  13. 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. ...

  14. 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…

  15. 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…

  16. 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…

  17. Beijing Lineage of MDR Mycobacterium tuberculosis in Bulgaria, 2007–2011

    PubMed Central

    Bachiyska, Elizabeta; Yordanova, Stanislava; Atanasova, Yuliana; Brankova, Nadia; Levterova, Viktoria; Sengstake, Sarah; Anthony, Richard; Bergval, Indra; Sola, Christophe; Kantardjiev, Todor

    2014-01-01

    To assess the spread of the Mycobacterium tuberculosis Beijing genotype among patients with multidrug-resistant and extensively resistant tuberculosis in Bulgaria, we genotyped 188 (72%) of 261 microbiologically confirmed resistant isolates obtained during 2007–2011. The estimated prevalence of the Beijing genotype among these patients was 3.2%. PMID:25340498

  18. Beijing lineage of MDR Mycobacterium tuberculosis in Bulgaria, 2007-2011.

    PubMed

    Panaiotov, Stefan; Bachiyska, Elizabeta; Yordanova, Stanislava; Atanasova, Yuliana; Brankova, Nadia; Levterova, Viktoria; Sengstake, Sarah; Anthony, Richard; Bergval, Indra; Sola, Christophe; Kantardjiev, Todor

    2014-11-01

    To assess the spread of the Mycobacterium tuberculosis Beijing genotype among patients with multidrug-resistant and extensively resistant tuberculosis in Bulgaria, we genotyped 188 (72%) of 261 microbiologically confirmed resistant isolates obtained during 2007-2011. The estimated prevalence of the Beijing genotype among these patients was 3.2%.

  19. Tuberculosis Risk among Medical Trainees, Pune, India.

    PubMed

    Basavaraj, Anita; 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

    2016-03-01

    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.

  20. Tuberculosis genotyping information management system: enhancing tuberculosis surveillance in the United States.

    PubMed

    Ghosh, Smita; Moonan, Patrick K; Cowan, Lauren; Grant, Juliana; Kammerer, Steve; Navin, Thomas R

    2012-06-01

    Molecular characterization of Mycobacterium tuberculosis complex isolates (genotyping) can be used by public health programs to more readily identify tuberculosis (TB) transmission. The Centers for Disease Control and Prevention's National Tuberculosis Genotyping Service has offered M. tuberculosis genotyping for every culture-confirmed case in the United States since 2004. The TB Genotyping Information Management System (TB GIMS), launched in March 2010, is a secure online database containing genotype results linked with case characteristics from the national TB registry for state and local TB programs to access, manage and analyze these data. As of September 2011, TB GIMS contains genotype results for 89% of all culture-positive TB cases for 2010. Over 400 users can generate local and national reports and maps using TB GIMS. Automated alerts on geospatially concentrated cases with matching genotypes that may represent outbreaks are also generated by TB GIMS. TB genotyping results are available to enhance national TB surveillance and apply genotyping results to conduct TB control activities in the United States.

  1. Screening programmes for tuberculosis in new entrants across Europe.

    PubMed

    Coker, R J; Bell, A; Pitman, R; Hayward, A; Watson, J

    2004-08-01

    Screening foreign-born groups with high rates of tuberculosis may help to ensure that they can benefit from early treatment and minimise onward transmission. In January 2003, we surveyed new entrant screening programmes in Europe. Of the 26 countries from whom a response was received, 13 (50%) conducted no specific tuberculosis screening. Of 13 countries with programmes, none conducted pre-entry screening, three conducted screening at ports of entry, and nine screened in other centres. All 13 principally screened refugees. All programmes used chest X-rays as a screening tool, but no two countries took the same specific clinical approach.

  2. [Urogenital tuberculosis today].

    PubMed

    Zhukova, I I; Kul'chavenia, E V; Kholtobin, D P; Brizhatiuk, E V; Khomiakov, V T; Osadchiĭ, A V

    2013-01-01

    In order to analyze the structure of urogenital tuberculosis, retrospective analysis of medical records of 131 patients with newly diagnosed urogenital tuberculosis observed in the Novosibirsk Regional TB Dispensary from 2009 to 2011 was performed. The renal tuberculosis is main form in the structure is urotuberculosis, detected in 75% of patients, and widespread destructive forms of the disease were diagnosed in more than half of cases. Isolated nephrotuberculosis was more often diagnosed in women--56.8%. 15.9% of patients had asymptomatic nephrotuberculosis; one-third of patients complained of pain in the lumbar region and frequent painful urination (35.2 and 39.8%, respectively); symptoms of intoxication were present in 17% of patients, renal colic--in 9.1%, and gross hematuria--in 7.9% of patients. Mycobacteriuria in isolated nephrotuberculosis was detected in 31.8% of cases. Acute tuberculous orchiepididymitis developed in 35.7% of patients, hemospermia was observed in 7.1% of patients, dysuria was in 35.7% of patients. The pain in the perineum, frequent painful urination (both by 31.6%), hemospermia (26.3%) were main complaints in prostate tuberculosis. Mycobacteria was detected in 10.5% of cases. It was found that urogenital tuberculosis has no pathognomonic symptoms; the most alarming manifestations include long-term dysuria, hematuria, hemospermia.

  3. The Importance of First Impressions: Early Events in Mycobacterium tuberculosis Infection Influence Outcome.

    PubMed

    Cadena, Anthony M; Flynn, JoAnne L; Fortune, Sarah M

    2016-04-05

    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.

  4. Tuberculosis of the oesophagus

    PubMed Central

    Fahmy, A. R.; Guindi, R.; Farid, A.

    1969-01-01

    A case of primary tuberculosis of the oesophagus is presented; the patient was successfully treated by oesophagectomy. The condition, being rare, has stimulated the authors to review the literature concerning primary and secondary oesophageal tuberculosis. The history, modes of infection, the pathology, clinical picture, diagnosis, investigations, and methods of treatment are discussed. In contradistinction to the secondary disease, which is terminal, primary tuberculosis of the oesophagus is a curable disease with a fairly good prognosis. The case report shows that the surgeon should pay careful attention to the site of the anastomosis; otherwise post-operative stricture can develop. Even this responds well to dilatations and the patient can regain normal health. PMID:5821628

  5. CT of abdominal tuberculosis

    SciTech Connect

    Epstein, B.M.; Mann, J.H.

    1982-11-01

    Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms of peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.

  6. [The diagnosis of pulmonary tuberculosis].

    PubMed

    Koyama, Sekiya; Sakaguchi, Nobuki; Hotta, Jyunnichi

    2012-08-01

    Mycobacterium tuberculosis (M. tuberculosis) infects all organs in the body; however, lung infection is the primary lesion. The total number of infections is decreasing, but the percentage of infections in older people is rising. Because this disease is due to infection with M. tuberculosis, the diagnosis requires the presence of M. tuberculosis. Chest X-ray and CT are very powerful tools to suggest the presence of M. tuberculosis infection. Pathological examination of the tissues also shows the typical findings of M. tuberculosis infection; however, the presence of the bacterium was not proven in certain cases of M. tuberculosis infection, and especially in cases of latent infection. Recently, the whole-blood interferon--gamma test (QuantiFERON-TB, QFT) became more popular than the tuberculin skin test. It is reported that the specificity and sensitivity of QFT are similar to or better than the tuberculin skin test. However, it should be noted that QFT positive does not automatically lead to a diagnosis of active M. tuberculosis infection and that QFT is one of the supplementary tests in the diagnosis of M. tuberculosis infection. Currently, massive infection with M. tuberculosis is increasing. The precise responsible linkage in massive infection with M. tuberculosis needs DNA polymorphism analysis using variable numbers of tandem repeats (VNTR) or restricted fragment length polymorphism (RFLP).

  7. 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.

  8. Spectrum of urogenital tuberculosis.

    PubMed

    Kulchavenya, Ekaterina; Zhukova, Irina; Kholtobin, Denis

    2013-10-01

    Urogenital tuberculosis (UGTB) plays an important role because its complications may be fatal, it significantly reduces quality of life, and it is often associated with AIDS. Diagnosis of UGTB is often delayed. We analyzed 131 case histories of UGTB patients from the years 2009-2011. Gender, age, and the clinical form and main features of the disease were taken into account. The most common form was kidney tuberculosis (74.8%). Isolated kidney tuberculosis (KTB) more often occurs in women: 56.8%. Patients of middle and old age more often showed the stage of cavernous KTB; younger patients had smaller forms. Among all cases, an asymptomatic course was seen in 12.2% and, among cases of KTB, in 15.9%. Every third patient complained of flank pain and dysuria (35.2% and 39.8%, respectively); 17% presented with toxicity symptoms, 9.1% with renal colic, and 7.9% with gross hematuria. Mycobacterium tuberculosis (MTB) in urine was found in 31.8% of cases in all levels of isolated KTB. UGTB has no specific symptom; even sterile pyuria occurs only in 25%. The acute onset of tuberculous orchiepididymitis was seen in 35.7% of patients, hemospermia in 7.1%, and dysuria in 35.7%. The most common complaints for prostate tuberculosis were perineal pain (31.6%), dysuria (also 31.6%), and hemospermia (26.3%). MTB in prostate secretion/ejaculate was revealed in 10.5% of this group. All urogenital tract infections should be suspected as UGTB in patients who are living in a region with a high incidence rate, who have had contact with tuberculosis infection, and who have a recurrence of the disease that is resistant to standard therapy.

  9. Spatial Dynamics of Bovine Tuberculosis in the Autonomous Community of Madrid, Spain (2010–2012)

    PubMed Central

    de la Cruz, Maria Luisa; Perez, Andres; Bezos, Javier; Pages, Enrique; Casal, Carmen; Carpintero, Jesus; Romero, Beatriz; Dominguez, Lucas; Barker, Christopher M.; Diaz, Rosa; Alvarez, Julio

    2014-01-01

    Progress in control of bovine tuberculosis (bTB) is often not uniform, usually due to the effect of one or more sometimes unknown epidemiological factors impairing the success of eradication programs. Use of spatial analysis can help to identify clusters of persistence of disease, leading to the identification of these factors thus allowing the implementation of targeted control measures, and may provide some insights of disease transmission, particularly when combined with molecular typing techniques. Here, the spatial dynamics of bTB in a high prevalence region of Spain were assessed during a three year period (2010–2012) using data from the eradication campaigns to detect clusters of positive bTB herds and of those infected with certain Mycobacterium bovis strains (characterized using spoligotyping and VNTR typing). In addition, the within-herd transmission coefficient (β) was estimated in infected herds and its spatial distribution and association with other potential outbreak and herd variables was evaluated. Significant clustering of positive herds was identified in the three years of the study in the same location (“high risk area”). Three spoligotypes (SB0339, SB0121 and SB1142) accounted for >70% of the outbreaks detected in the three years. VNTR subtyping revealed the presence of few but highly prevalent strains within the high risk area, suggesting maintained transmission in the area. The spatial autocorrelation found in the distribution of the estimated within-herd transmission coefficients in herds located within distances <14 km and the results of the spatial regression analysis, support the hypothesis of shared local factors affecting disease transmission in farms located at a close proximity. PMID:25536514

  10. Spatial dynamics of bovine tuberculosis in the Autonomous Community of Madrid, Spain (2010-2012).

    PubMed

    de la Cruz, Maria Luisa; Perez, Andres; Bezos, Javier; Pages, Enrique; Casal, Carmen; Carpintero, Jesus; Romero, Beatriz; Dominguez, Lucas; Barker, Christopher M; Diaz, Rosa; Alvarez, Julio

    2014-01-01

    Progress in control of bovine tuberculosis (bTB) is often not uniform, usually due to the effect of one or more sometimes unknown epidemiological factors impairing the success of eradication programs. Use of spatial analysis can help to identify clusters of persistence of disease, leading to the identification of these factors thus allowing the implementation of targeted control measures, and may provide some insights of disease transmission, particularly when combined with molecular typing techniques. Here, the spatial dynamics of bTB in a high prevalence region of Spain were assessed during a three year period (2010-2012) using data from the eradication campaigns to detect clusters of positive bTB herds and of those infected with certain Mycobacterium bovis strains (characterized using spoligotyping and VNTR typing). In addition, the within-herd transmission coefficient (β) was estimated in infected herds and its spatial distribution and association with other potential outbreak and herd variables was evaluated. Significant clustering of positive herds was identified in the three years of the study in the same location ("high risk area"). Three spoligotypes (SB0339, SB0121 and SB1142) accounted for >70% of the outbreaks detected in the three years. VNTR subtyping revealed the presence of few but highly prevalent strains within the high risk area, suggesting maintained transmission in the area. The spatial autocorrelation found in the distribution of the estimated within-herd transmission coefficients in herds located within distances <14 km and the results of the spatial regression analysis, support the hypothesis of shared local factors affecting disease transmission in farms located at a close proximity.

  11. Metallobiology of Tuberculosis

    PubMed Central

    Rodriguez, G. Marcela; Neyrolles, Olivier

    2016-01-01

    Transition metals are essential constituents of all living organisms, playing crucial structural and catalytic parts in many enzymes and transcription factors. However, transition metals can also be toxic when present in excess. Their uptake and efflux rates must therefore be carefully controlled by biological systems. In this chapter, we summarize the current knowledge about uptake and efflux systems in Mycobacterium tuberculosis for mainly three of these metals, namely iron, zinc and copper. We also propose questions fur future research in the field of metallobiology of host-pathogen interactions in tuberculosis. PMID:26103977

  12. Pathogen-derived biomarkers for active tuberculosis diagnosis.

    PubMed

    Tucci, Paula; González-Sapienza, Gualberto; Marin, Monica

    2014-01-01

    Tuberculosis (TB) is an infectious disease caused by members of Mycobacterium tuberculosis complex. Despite the availability of effective treatments, TB remains a major public health concern in most low and middle-income countries, representing worldwide the second leading cause of death from an infectious disease. Inadequate case detection and failures to classify the disease status hamper proper TB control. The limitations of the conventional diagnostic methods have encouraged much research activities in this field, but there is still an urgent need for an accurate point of care test for active TB diagnosis. A rapid, precise, and inexpensive TB diagnostic test would allow an earlier implementation of an appropriate treatment and the reduction of disease transmission. Pathogen-derived molecules present in clinical specimens of affected patients are being validated for that purpose. This short review aims to summarize the available data regarding biomarkers derived from M. tuberculosis, and their current usage in active TB diagnosis.

  13. The re-emergence of tuberculosis: what have we learnt from molecular epidemiology?

    PubMed

    Borgdorff, M W; van Soolingen, D

    2013-10-01

    Tuberculosis (TB) has re-emerged over the past two decades: in industrialized countries in association with immigration, and in Africa owing to the human immunodeficiency virus epidemic. Drug-resistant TB is a major threat worldwide. The variable and uncertain impact of TB control necessitates not only better tools (diagnostics, drugs, and vaccines), but also better insights into the natural history and epidemiology of TB. Molecular epidemiological studies over the last two decades have contributed to such insights by answering long-standing questions, such as the proportion of cases attributable to recent transmission, risk factors for recent transmission, the occurrence of multiple Mycobacterium tuberculosis infection, and the proportion of recurrent TB cases attributable to re-infection. M. tuberculosis lineages have been identified and shown to be associated with geographical origin. The Beijing genotype is strongly associated with multidrug resistance, and may have escaped from bacille Calmette-Guérin-induced immunity. DNA fingerprinting has quantified the importance of institutional transmission and laboratory cross-contamination, and has helped to focus contact investigations. Questions to be answered in the near future with whole genome sequencing include identification of chains of transmission within clusters of patients, more precise quantification of mixed infection, and transmission probabilities and rates of progression from infection to disease of various M. tuberculosis lineages, as well as possible variations in vaccine efficacy by lineage. Perhaps most importantly, dynamics in the population structure of M. tuberculosis in response to control measures in high-prevalence areas should be better understood.

  14. Subtle genotypic changes can be observed soon after diagnosis in Mycobacterium tuberculosis infection.

    PubMed

    Pérez-Lago, Laura; Rodríguez Borlado, Ana Isabel; Comas, Iñaki; Herranz, Marta; Ruiz-Serrano, María Jesús; Bouza, Emilio; García-de-Viedma, Darío

    2016-09-01

    Clonal variants of Mycobacterium tuberculosis (MTB) coexist in specific patients, although the dynamics of their emergence is unknown. We used MIRU-VNTR to detect microevolution leading to variants of MTB in 3 out of 19 patients (15%) soon after diagnosis (61-85days). Most harbored SNPs and for some of them a potential functional role was suggested. Microevolution in tuberculosis seems to occur sooner and more often than expected and could affect tracking of transmission.

  15. Evolution of drug-resistant tuberculosis: a tale of two species.

    PubMed Central

    Iseman, M D

    1994-01-01

    The history of the disease tuberculosis is briefly discussed. Now human societal failures have potentiated the evolution of drug-resistant strains of the tubercle bacillus in the United States and around the world. Until recently, this evolutionary change largely posed a threat to the health and survival of the individual in whom inadequate therapy promoted the drug resistance. However, the human immunodeficiency virus epidemic threatens to promote wholesale transmission of multidrug-resistant tuberculosis with the potential for immense morbidity and mortality. Reinforced treatment and control programs for tuberculosis are vital. PMID:8146134

  16. New approaches in the diagnosis and treatment of latent tuberculosis infection

    PubMed Central

    2010-01-01

    With nearly 9 million new active disease cases and 2 million deaths occurring worldwide every year, tuberculosis continues to remain a major public health problem. Exposure to Mycobacterium tuberculosis leads to active disease in only ~10% people. An effective immune response in remaining individuals stops M. tuberculosis multiplication. However, the pathogen is completely eradicated in ~10% people while others only succeed in containment of infection as some bacilli escape killing and remain in non-replicating (dormant) state (latent tuberculosis infection) in old lesions. The dormant bacilli can resuscitate and cause active disease if a disruption of immune response occurs. Nearly one-third of world population is latently infected with M. tuberculosis and 5%-10% of infected individuals will develop active disease during their life time. However, the risk of developing active disease is greatly increased (5%-15% every year and ~50% over lifetime) by human immunodeficiency virus-coinfection. While active transmission is a significant contributor of active disease cases in high tuberculosis burden countries, most active disease cases in low tuberculosis incidence countries arise from this pool of latently infected individuals. A positive tuberculin skin test or a more recent and specific interferon-gamma release assay in a person without overt signs of active disease indicates latent tuberculosis infection. Two commercial interferon-gamma release assays, QFT-G-IT and T-SPOT.TB have been developed. The standard treatment for latent tuberculosis infection is daily therapy with isoniazid for nine months. Other options include therapy with rifampicin for 4 months or isoniazid + rifampicin for 3 months or rifampicin + pyrazinamide for 2 months or isoniazid + rifapentine for 3 months. Identification of latently infected individuals and their treatment has lowered tuberculosis incidence in rich, advanced countries. Similar approaches also hold great promise for other

  17. The HIV-associated tuberculosis epidemic--when will we act?

    PubMed

    Harries, Anthony D; Zachariah, Rony; Corbett, Elizabeth L; Lawn, Stephen D; Santos-Filho, Ezio T; Chimzizi, Rhehab; Harrington, Mark; Maher, Dermot; Williams, Brian G; De Cock, Kevin M

    2010-05-29

    Despite policies, strategies, and guidelines, the epidemic of HIV-associated tuberculosis continues to rage, particularly in southern Africa. We focus our attention on the regions with the greatest burden of disease, especially sub-Saharan Africa, and concentrate on prevention of tuberculosis in people with HIV infection, a challenge that has been greatly neglected. We argue for a much more aggressive approach to early diagnosis and treatment of HIV infection in affected communities, and propose urgent assessment of frequent testing for HIV and early start of antiretroviral treatment (ART). This approach should result in short-term and long-term declines in tuberculosis incidence through individual immune reconstitution and reduced HIV transmission. Implementation of the 3Is policy (intensified tuberculosis case finding, infection control, and isoniazid preventive therapy) for prevention of HIV-associated tuberculosis, combined with earlier start of ART, will reduce the burden of tuberculosis in people with HIV infection and provide a safe clinical environment for delivery of ART. Some progress is being made in provision of HIV care to HIV-infected patients with tuberculosis, but too few receive co-trimoxazole prophylaxis and ART. We make practical recommendations about how to improve this situation. Early HIV diagnosis and treatment, the 3Is, and a comprehensive package of HIV care, in association with directly observed therapy, short-course (DOTS) for tuberculosis, form the basis of prevention and control of HIV-associated tuberculosis. This call to action recommends that both HIV and tuberculosis programmes exhort implementation of strategies that are known to be effective, and test innovative strategies that could work. The continuing HIV-associated tuberculosis epidemic needs bold but responsible action, without which the future will simply mirror the past.

  18. Does Non-Central Nervous System Tuberculosis Increase the Risk of Ischemic Stroke? A Population-Based Propensity Score-Matched Follow-Up Study

    PubMed Central

    Wu, Chueh-Hung; Chen, Li-Sheng; Yen, Ming-Fang; Chiu, Yueh-Hsia; Fann, Ching-Yuan; Chen, Hsiu-Hsi; Pan, Shin-Liang

    2014-01-01

    Background Previous studies on the association between tuberculosis and the risk of developing ischemic stroke have generated inconsistent results. We therefore performed a population-based, propensity score-matched longitudinal follow-up study to investigate whether contracting non-central nervous system (CNS) tuberculosis leads to an increased risk of ischemic stroke. Methods We used a logistic regression model that includes age, sex, pre-existing comorbidities and socioeconomic status as covariates to compute the propensity score. A total of 5804 persons with at least three ambulatory visits in 2001 with the principal diagnosis of non-CNS tuberculosis were enrolled in the tuberculosis group. The non-tuberculosis group consisted of 5804, propensity score-matched subjects without tuberculosis. The three-year ischemic stroke-free survival rates for these 2 groups were estimated using the Kaplan-Meier method. The stratified Cox proportional hazards regression was used to estimate the effect of tuberculosis on the occurrence of ischemic stroke. Results During three-year follow-up, 176 subjects in the tuberculosis group (3.0%) and 207 in the non-tuberculosis group (3.6%) had ischemic stroke. The hazard ratio for developing ischemic stroke in the tuberculosis group was 0.92 compared to the non-tuberculosis group (95% confidence interval: 0.73–1.14, P = 0.4299). Conclusions Non-CNS tuberculosis does not increase the risk of subsequent ischemic stroke. PMID:25048551

  19. Genetic variation of Mycobacterium tuberculosis circulating in Kharkiv Oblast, Ukraine

    PubMed Central

    2011-01-01

    Background A persistent increase of tuberculosis cases has recently been noted in the Ukraine. The reported incidence of drug-resistant isolates of M. tuberculosis is growing steadily; however, data on the genetic variation of isolates of M. tuberculosis circulating in northern Ukraine and on the spectrum and frequency of occurrence of mutations determining resistance to the principal anti-tuberculosis drugs isoniazid and rifampicin have not yet been reported. Methods Isolates of M. tuberculosis from 98 tuberculosis patients living in Kharkiv Oblast (Ukraine) were analyzed using VNTR- and RFLP-IS6110-typing methods. Mutations associated with resistance to rifampicin and isoniazid were detected by RFLP-PCR methods, and also confirmed by sequencing. Results We identified 75 different genetic profiles. Thirty four (34%) isolates belonged to the Beijing genotype and 23 (23%) isolates belonged to the LAM family. A cluster of isolates belonging to the LAM family had significant genetic heterogeneity, indicating that this family had an ancient distribution and circulation in this geographical region. Moreover, we found a significant percentage of the isolates (36%) belonged to as yet unidentified families of M. tuberculosis or had individual non-clustering genotypes. Mutations conferring rifampicin and isoniazid resistance were detected in 49% and 54% isolates, respectively. Mutations in codon 531 of the rpoB gene and codon 315 of the katG gene were predominant among drug-resistant isolates. An association was found for belonging to the LAM strain family and having multiple drug resistance (R = 0.27, p = 0.0059) and also for the presence of a mutation in codon 531 of the rpoB gene and belonging to the Beijing strain family (R = 0.2, p = 0.04). Conclusions Transmission of drug-resistant isolates seems to contribute to the spread of resistant TB in this oblast. The Beijing genotype and LAM genotype should be seen as a major cause of drug resistant TB in this region. PMID

  20. In vitro susceptibility testing of Mycobacterium tuberculosis complex strains isolated from seals to antituberculosis drugs.

    PubMed

    Bernardelli, Amelia; Morcillo, Nora; Loureiro, Julio; Quse, Viviana; Davenport, Silvana

    2004-06-01

    Mycobacteria strains belonging to the Mycobacterium tuberculosis complex were isolated from seals found in the South Atlantic. The animals were received in Mundo Marino installations and treated for Mycobacterium tuberculosis complex by conventional therapy of intensive care and enriched food supply; however, in all cases treatment failed. Necropsies of all animals revealed extensive lesions compatible with tuberculosis involving lungs, liver, spleen and lymphatic nodes. Classical biochemical methods as well as molecular techniques using the IS6110 probes were performed for mycobacterial identification. Furthermore, the LCx M. tuberculosis assay (Abbott Laboratories) identified all strains as Mycobacterium tuberculosis complex members. The in vitro susceptibility pattern was examined in mycobacterial strains isolated from seven seals and in 3 reference strains--BCG, H37Rv (M. tuberculosis) and AN5 (Mycobacterium bovis)--to 4 medications--isoniazid, rifampin, streptomycin and ethambutol. Minimal inhibitory drug concentrations were determined by the Mycobacterial Growth Indicator Tube (BD Argentina) method and a microdilution and colorimetric assay using 3-(4-5 dimethyltiazol-2)-2,5 diphenyltetrazolium bromide. All the isolates and the reference strains BCG and AN5 were inhibited by MIC values similar to those of H37Rv with good agreement obtained by both techniques. These findings suggest that a therapeutic regimen aimed to seals diagnosed with tuberculosis play an important role in the prevention of tuberculosis transmission from infected animals to humans that are in routine contact with them.

  1. Reflections on the immunology of tuberculosis: will we ever unravel the skein?

    PubMed Central

    2014-01-01

    Many and large dumps exist in our knowledge about Mycobacterium tuberculosis infection and disease in infants and children. We still do not understand why some individuals do acquire and others do not acquire the infection in the presence of the same risk factors. We do not understand why some individuals convert from latent to active tuberculosis and why other individuals convert from active to inactive tuberculosis even without treatment. As a matter of fact the immune system mounts a bouncing, robust and polyedral defence against Mycobacterium tuberculosis, but the bacillus is so much artful and dextrous that it has ahead from this immunological fierce accoutrements. Mycobacterium tuberculosis survival, multiplication, and transmission are largely favoured by the immune mechanisms. The granuloma itself is more bacillus- than host-protective. These abilities make Mycobacterium tuberculosis one of more successful human pathogens, but dumps in our knowledge and the counterproductive immunity hinder development of new diagnostics, therapies and vaccines. This occurs in front of an infection which engages one third of the world population and a disease which kills in a year about 1.5 million individuals worldwide. Understanding mechanisms and meaning of immune response in tuberculosis marks out the foundations of strategies with a view to prepare effective vaccines and reliable diagnostic tools as well as to build up therapeutic weapons. To gain these objectives is vital and urgent considering that tuberculosis is a common cause of morbidity and is a leading cause of death. PMID:24564297

  2. Molecular, Spatial, and Field Epidemiology Suggesting TB Transmission in Community, Not Hospital, Gaborone, Botswana.

    PubMed

    Surie, Diya; Fane, Othusitse; Finlay, Alyssa; Ogopotse, Matsiri; Tobias, James L; Click, Eleanor S; Modongo, Chawangwa; Zetola, Nicola M; Moona