Mediational Effects of Self-Efficacy Dimensions in the Relationship between Knowledge of Dengue and Dengue Preventive Behaviour with Respect to Control of Dengue Outbreaks: A Structural Equation Model of a Cross-Sectional Survey
Background Dengue fever is endemic in Malaysia, with frequent major outbreaks in urban areas. The major control strategy relies on health promotional campaigns aimed at encouraging people to reduce mosquito breeding sites close to people's homes. However, such campaigns have not always been 100% effective. The concept of self-efficacy is an area of increasing research interest in understanding how health promotion can be most effective. This paper reports on a study of the impact of self-efficacy on dengue knowledge and dengue preventive behaviour. Methods and Findings We recruited 280 adults from 27 post-outbreak villages in the state of Terengganu, east coast of Malaysia. Measures of health promotion and educational intervention activities and types of communication during outbreak, level of dengue knowledge, level and strength of self-efficacy and dengue preventive behaviour were obtained via face-to-face interviews and questionnaires. A structural equation model was tested and fitted the data well (?2?=?71.659, df?=?40, p?=?0.002, RMSEA?=?0.053, CFI?=?0.973, TLI?=?0.963). Mass media, local contact and direct information-giving sessions significantly predicted level of knowledge of dengue. Level and strength of self-efficacy fully mediated the relationship between knowledge of dengue and dengue preventive behaviours. Strength of self-efficacy acted as partial mediator in the relationship between knowledge of dengue and dengue preventive behaviours. Conclusions To control and prevent dengue outbreaks by behavioural measures, health promotion and educational interventions during outbreaks should now focus on those approaches that are most likely to increase the level and strength of self-efficacy.
Isa, Affendi; Loke, Yoon K.; Smith, Jane R.; Papageorgiou, Alexia; Hunter, Paul R.
Background Dengue has propagated widely through the Americas. Most countries have not been able to maintain permanent larval mosquito control programs, and the long-term effects of control actions have rarely been documented. Methodology The study design was based on a before-and-after citywide assessment of Aedes aegypti larval indices and the reported incidence of dengue in Clorinda, northeastern Argentina, over 2003–2007. Interventions were mainly based on focal treatment with larvicides of every mosquito developmental site every four months (14 cycles), combined with limited source reduction efforts and ultra-low-volume insecticide spraying during emergency operations. The program conducted 120,000 house searches for mosquito developmental sites and 37,000 larvicide applications. Principal Findings Random-effects regression models showed that Breteau indices declined significantly in nearly all focal cycles compared to pre-intervention indices clustered by neighborhood, after allowing for lagged effects of temperature and rainfall, baseline Breteau index, and surveillance coverage. Significant heterogeneity between neighborhoods was revealed. Larval indices seldom fell to 0 shortly after interventions at the same blocks. Large water-storage containers were the most abundant and likely to be infested. The reported incidence of dengue cases declined from 10.4 per 10,000 in 2000 (by DEN-1) to 0 from 2001 to 2006, and then rose to 4.5 cases per 10,000 in 2007 (by DEN-3). In neighboring Paraguay, the reported incidence of dengue in 2007 was 30.6 times higher than that in Clorinda. Conclusions Control interventions exerted significant impacts on larval indices but failed to keep them below target levels during every summer, achieved sustained community acceptance, most likely prevented new dengue outbreaks over 2003–2006, and limited to a large degree the 2007 outbreak. For further improvement, a shift is needed towards a multifaceted program with intensified coverage and source reduction efforts, lids or insecticide-treated covers to water-storage containers, and a broad social participation aiming at long-term sustainability.
Gurtler, Ricardo E.; Garelli, Fernando M.; Coto, Hector D.
Dengue has affected the north provinces of Argentina, mainly Salta province. The 2009 outbreak, with 5 deaths and >27,000 infected, was the most important, and the first to extend into the central area of the country. This article includes research on seasonal Aedes aegypti abundance variation in Orán City (Salta province), and determination of the date of mosquito population increase and an estimation of the date of maximum rate of increase as well as the intrinsic rate of natural increase (r), to detect the optimal time to apply vector control measures. Between September 2005 and March 2007, ovitraps were randomly distributed in the city to collect Ae. aegypti eggs. The variation observed in the number of collected eggs was described by fitting a third-degree polynomial by the least square method, allowing to determine the time when population increase began (week 1), after the temperate and dry season. Eggs were collected throughout the year, with the highest variation in abundance during the warm and rainy season, and the maximum value registered in February 2007. The rate of increase of the number of eggs laid per week peaked between weeks 9 and 10 after the beginning of the population increase (week 1). Week 1 depends on temperature, it occurs after getting over the thermal threshold and the needed accumulation of 160 degree-day is reached. Consequently, week 1 changes depending on temperature. Peak abundance of eggs during 2005-2006 was recorded on week 15 (after week 1); during 2006-2007, the peak was observed on week 22. Estimation of the intrinsic rate of natural increase (r) of Ae. aegypti is useful not only to determine optimal time to apply vector control measures with better cost-benefit, but also to add an insecticide control strategy against the vector to diminish the possibility of resistance. PMID:20925528
Estallo, Elizabet L; Ludueña-Almeida, Francisco F; Visintin, Andrés M; Scavuzzo, Carlos M; Introini, María V; Zaidenberg, Mario; Almirón, Walter R
We analyzed surveillance data of a dengue outbreak (2010) reported to the Hadramout Health Office (Yemen) and retrospectively analyzed dengue-related epidemiological and entomological events reported in Hadramout from 2005 to 2009. A total of 630 immunoglobulin M (IgM) -confirmed dengue cases of 982 febrile cases was reported during the period from February to June of 2010; 12 cases died, giving case fatality a rate of 1.9%. Among febrile cases, the highest proportion of dengue cases (37.3%) was reported in the 15- to 24-year-old age group. The overall attack rate was 0.89/1,000. The average number of cases reported by month over the preceding 5-year period compared with the 2010 data is consistent with endemicity of dengue in the region and supports epidemic designation for the dengue activity in 2010. Recognition of endemic dengue transmission and potential for substantial dengue epidemics highlight the need for consistent laboratory-based surveillance that can support prevention and control activities accordingly. PMID:22665621
Bin Ghouth, Abdulla Salim; Amarasinghe, Ananda; Letson, G William
We analyzed surveillance data of a dengue outbreak (2010) reported to the Hadramout Health Office (Yemen) and retrospectively analyzed dengue-related epidemiological and entomological events reported in Hadramout from 2005 to 2009. A total of 630 immunoglobulin M (IgM) -confirmed dengue cases of 982 febrile cases was reported during the period from February to June of 2010; 12 cases died, giving case fatality a rate of 1.9%. Among febrile cases, the highest proportion of dengue cases (37.3%) was reported in the 15- to 24-year-old age group. The overall attack rate was 0.89/1,000. The average number of cases reported by month over the preceding 5-year period compared with the 2010 data is consistent with endemicity of dengue in the region and supports epidemic designation for the dengue activity in 2010. Recognition of endemic dengue transmission and potential for substantial dengue epidemics highlight the need for consistent laboratory-based surveillance that can support prevention and control activities accordingly.
Ghouth, Abdulla Salim Bin; Amarasinghe, Ananda; Letson, G. William
Dengue fever has now affected all the major cities of country. About 41,354 patients underwent antibody screening for dengue fever from Shaukat Khanum Memorial Cancer Hospital, Lahore, during the epidemic period (October 1st 2010 to December 20th 2010). Out of them, 1294 (3.1%) patients were positive for IgM antibodies, and 124 (0.3%) for IgG antibodies. A total of 722 (1.7%) patients were borderline positive for IgM antibodies and 108 (0.26%) were borderline positive for IgG antibodies. Dengue fever has emerged as a global problem over the last 5 years. It has also hit Lahore badly especially after the floods in 2010. High index of suspicion should be there in case of related symptoms. PMID:23458054
Hassan, Usman; Loya, Asif; Mehmood, Muhammad Tariq; Nazeer, Hammad; Sultan, Faisal
BackgroundDengue has propagated widely through the Americas. Most countries have not been able to maintain permanent larval mosquito control programs, and the long-term effects of control actions have rarely been documented.MethodologyThe study design was based on a before-and-after citywide assessment of Aedes aegypti larval indices and the reported incidence of dengue in Clorinda, northeastern Argentina, over 2003–2007. Interventions were mainly
Ricardo E. Gürtler; Fernando M. Garelli; Héctor D. Coto
Dengue virus was detected for the first time in Chile, in an outbreak of dengue fever on Easter Island. The virus was isolated in tissue culture and characterized by reverse transcription-polymerase chain reaction as being dengue type 1. PMID:14718094
Perret, Cecilia; Abarca, Katia; Ovalle, Jimena; Ferrer, Pablo; Godoy, Paula; Olea, Andrea; Aguilera, Ximena; Ferrés, Marcela
Dengue is a viral disease usually transmitted by Aedes aegypti mosquitoes. Dengue outbreaks in the Americas reported in medical literature and to the Pan American Health Organization are described. The outbreak history from 1600 to 2010 was categorized into four phases: Introduction of dengue in the Americas (1600-1946); Continental plan for the eradication of the Ae. aegypti (1947-1970) marked by a successful eradication of the mosquito in 18 continental countries by 1962; Ae. aegypti reinfestation (1971-1999) caused by the failure of the mosquito eradication program; Increased dispersion of Ae. aegypti and dengue virus circulation (2000-2010) characterized by a marked increase in the number of outbreaks. During 2010 > 1.7 million dengue cases were reported, with 50,235 severe cases and 1,185 deaths. A dramatic increase in the number of outbreaks has been reported in recent years. Urgent global action is needed to avoid further disease spread. PMID:23042846
Brathwaite Dick, Olivia; San Martín, José L; Montoya, Romeo H; del Diego, Jorge; Zambrano, Betzana; Dayan, Gustavo H
Dengue is a viral disease usually transmitted by Aedes aegypti mosquitoes. Dengue outbreaks in the Americas reported in medical literature and to the Pan American Health Organization are described. The outbreak history from 1600 to 2010 was categorized into four phases: Introduction of dengue in the Americas (1600–1946); Continental plan for the eradication of the Ae. aegypti (1947–1970) marked by a successful eradication of the mosquito in 18 continental countries by 1962; Ae. aegypti reinfestation (1971–1999) caused by the failure of the mosquito eradication program; Increased dispersion of Ae. aegypti and dengue virus circulation (2000–2010) characterized by a marked increase in the number of outbreaks. During 2010 > 1.7 million dengue cases were reported, with 50,235 severe cases and 1,185 deaths. A dramatic increase in the number of outbreaks has been reported in recent years. Urgent global action is needed to avoid further disease spread.
Brathwaite Dick, Olivia; San Martin, Jose L.; Montoya, Romeo H.; del Diego, Jorge; Zambrano, Betzana; Dayan, Gustavo H.
The spreading dynamic of the 2004 dengue fever outbreak that occurred in Tartagal, Northwestern Argentina, was investigated. A total of 487 suspected dengue cases were recorded and geo-referenced. Maps of daily cases were generated for the 109 days of the outbreak. The epidemic affected the majority of the city within 11 days. The age-distribution of the cases was different from the population age-distribution. The spatio-temporal clustering of the cases was analyzed using Knox test concept. Results of the space and time geo-referencing of the cases showed outbreak spotlights and spreading patterns that could be related to entomologic and epidemiologic factors. An environmental risk prediction model was developed based on a synthetic multi-band image created from LandSat 5 TM satellite image. The potential and limitations of remote sensing data and spatial statistics as landscape epidemiology tools for a dengue surveillance strategy and prevention are discussed. PMID:17603989
Rotela, Camilo; Fouque, Florence; Lamfri, Mario; Sabatier, Phillipe; Introini, Virginia; Zaidenberg, Mario; Scavuzzo, Carlos
On September 26, 2012, a woman aged 35 years from Kosrae in the Federated States of Micronesia (FSM) was hospitalized with fever, headache, muscle pain, vomiting, leukopenia, and thrombocytopenia. A rapid diagnostic test (RDT) (Dengue Duo, Standard Diagnostics Inc.) was positive for dengue virus (DENV) nonstructural protein-1 (NS1). During the next week, seven more persons with suspected dengue were tested with the RDT, of whom three were RDT-positive for NS1 or anti-DENV immunoglobulin M (IgM). During October, the Kosrae State Department of Health Services, with support from the FSM Department of Health and Social Affairs and the World Health Organization (WHO), responded to the outbreak with enhanced surveillance, training in clinical management, analysis of hospital surge capacity, a rapid mosquito survey to identify species and distributions, and control measures. By March 14, 2013, approximately 3.7% of Kosrae State residents had been hospitalized with suspected dengue. The outbreak consumed scarce medical and public health services, including outpatient, inpatient, and laboratory services, resulting in redirection of human and material resources from other important medical and public health activities. Because the health consequences of dengue can be substantial in resource-limited settings, Pacific Island nations might wish to consider preparedness measures for dengue outbreaks such as developing and testing outbreak response plans and ensuring adequate capacity for epidemiologic surveillance and laboratory testing. PMID:23863704
A large outbreak of dengue fever (DF)\\/dengue haemorrhagic fever (DHF) occurred in Dhaka city, Bangladesh, in 2000. The present study was conducted on 105 clinically-suspected cases of DF to confirm the diagnosis, determine the major clinical manifestations and correlate the haemorrhagic manifestations with different dengue serotypes circulating during the outbreak. A total of 97 cases were positive for anti-dengue IgM
Monira Pervin; Shahina Tabassum; Mobarak Ali; Kazi Zulfiquer Mamun; Nazrul Islam
BackgroundPeriodic outbreaks of dengue fever occur in the United States Virgin Islands. In June 2005, an outbreak of dengue virus (DENV) serotype-2 with cases of dengue hemorrhagic fever (DHF) was detected in St. Croix, US Virgin Islands. The objective of this report is to describe this outbreak of DENV-2 and the findings of a case-control study examining risk factors for
Hamish Mohammed; Mary Ramos; Julie Armstrong; Jorge Muñoz-Jordán; Kathleen O. Arnold-Lewis; Aurimar Ayala; Gary G. Clark; Eugene S. Tull; Mark E. Beatty; Landon Myer
Background & objectives: Dengue is a major health problem in many parts of India and its neighbouring countries. Dengue cases have not been reported from Manipur, a northeastern State of India till 2007. But, the sudden outbreak of fever with febrile illness during 2007 and 2008, suspected to be dengue/dengue haemorrhagic fever was investigated to detect the causative agent. Potential impact of climatic variables on dengue transmission has been documented and hence the association between climatic factors, entomological parameters and dengue cases was also analysed. Methods: Forty two and 16 blood samples were collected from patients suspected to have dengue infection in the year 2007 and 2008, respectively. Viral RNA was extracted from serum samples and subjected to multiplex one step RT-PCR assay. Dengue specific amplicons were sequenced and phylogenetic analysis was carried out. Multiyear trend analysis and ‘t’ test were performed for the comparison of different meteorological variables between the years 2000-2004 and 2005-2008. Results: The aetiological agent was found to be DENV-2 and the phylogenetic analysis showed that the isolate was similar to that of Cambodian isolate. There was a significant difference in minimum temperature (P<0.05), Relative humidity - morning hours (P<0.001), relative humanity - afternoon hours (P<0.01) and cumulative precipitation (P< 0.05) between the years 2000-2004 and 2005-2008. Interpretation & conclusions: The sudden outbreak of dengue fever in Manipur State occurred was possibly due to the increased temperature, relative humidity and decrease in cumulative precipitation. These climatic factors would have contributed to the Aedes mosquito abundance and increased virus transmission. Proper diseases surveillance system integrated with meteorological warning system and management of vector breeding sites will prevent such outbreaks in future.
Sankari, T.; Hoti, S.L.; Singh, Th Bhubonchandra; Shanmugavel, J.
A dengue outbreak occurred in Kaohsiung City starting in July in 2001. We studied the clinical profile of all patients admitted to Kaohsiung Veterans General Hospital during this outbreak from July 2001 to January 2002. A total of 25 cases of clinically suspected dengue fever were treated during this period, and 13 of them were confirmed by laboratory results (13\\/25;
Ping-Chang Lai; Susan Shin-Jung Lee; Chih-Hsiang Kao; Yao-Shen Chen; Chun-Kai Huang; Wei-Ru Lin; Shue-Ren Wann; Hsi-Hsun Lin; Muh-Yong Yen; Yung-Ching Liu
Outbreaks of dengue occur in Queensland, Australia nearly every summer. In 2008-2009, there was an unusually large, protracted outbreak of dengue, comprised of 1,200 cases. We investigated the weather variables and their contribution to the 2008-2009 dengue outbreak in Queensland. Case data were obtained from the Communicable Disease Branch of Queensland Health for 2000-2010 for the towns of Cairns and Townsville. Monthly weather data (rainfall, maximum temperature, minimum temperature) and Southern Oscillation Index (SOI) was obtained from the Bureau of Meteorology (BOM). We used a negative binomial model to test associations between these variables and dengue. Lagged models were also created for one, two and three months. Our models suggest all weather variables but not the SOI were associated with dengue in both Cairns and Townsville, without a lag (p<0.01). No significant lag was seen with the weather variables. Rainfall and temperature preceding the 2008-2009 outbreak were also not significantly different (p<0.01) from other years. Short-term (non-lagged) weather variables were associated with the number of dengue cases in Cairns and Townsville. No lag was seen and no association was seen between the SOI and the number of dengue cases, which suggests there may be limited potential to predict large dengue outbreaks using climate variability. The large outbreak in 2008-2009 may have been driven by other, non-weather factors in addition to the immediate weather effect. PMID:24050094
Hasan, Tasnim; Bambrick, Hilary
BACKGROUND: This study was designed to find out a relationship of dengue infection with climatic factors such as rainfall, temperature and relative humidity during the dengue fever epidemic in the year 2003. Blood samples were collected from 1550 patients experiencing a febrile illness clinically consistent with dengue infection. Serological confirmation of Dengue Infection was done using Dengue Duo IgM and
Anita Chakravarti; Rajni Kumaria
Between 10 July and 23 October 1966 an epidemic of dengue hemorrhagic fever occurred on an island in the Gulf of Thailand. Fourteen cases of dengue-shock syndrome (with one death) and 20 of hemorrhagic-fever syndrome due to dengue occurred. An additional ...
P. E. Winter T. M. Yuill S. Udomaskdi D. Gould S. Nantapanich
Background Periodic outbreaks of dengue fever occur in the United States Virgin Islands. In June 2005, an outbreak of dengue virus (DENV) serotype-2 with cases of dengue hemorrhagic fever (DHF) was detected in St. Croix, US Virgin Islands. The objective of this report is to describe this outbreak of DENV-2 and the findings of a case-control study examining risk factors for DHF. Methodology/Principal Findings This is the largest dengue outbreak ever recorded in St. Croix, with 331 suspected dengue cases reported island-wide during 2005 (62.2 cases/10,000 population); 54% were hospitalized, 21% had at least one hemorrhagic manifestation, 28% had thrombocytopenia, 5% had DHF and 1 patient died. Eighty-nine laboratory-positive hospitalized patients were identified. Of these, there were 15 (17%) who met the WHO criteria for DHF (cases) and 74 (83%) who did not (controls). The only variable significantly associated with DHF on bivariate or multivariable analysis was age, with an adjusted odds ratio (95% confidence interval) of 1.033 (1.003,1.064). Conclusions/Significance During this outbreak of DENV-2, a high proportion of cases developed DHF and increasing age was significantly associated with DHF.
Mohammed, Hamish; Ramos, Mary; Armstrong, Julie; Munoz-Jordan, Jorge; Arnold-Lewis, Kathleen O.; Ayala, Aurimar; Clark, Gary G.; Tull, Eugene S.; Beatty, Mark E.
Background Dengue fever is a virus infection that is spread by the Aedes aegypti mosquito and can cause severe disease especially in children. Dengue fever is a major problem in tropical and sub-tropical regions of the world. Methodology/Principal Findings We invited dengue experts from around the world to attend meetings to discuss dengue surveillance. We reviewed literature, heard detailed reports on surveillance programs, and shared expert opinions. Results Presentations by 22 countries were heard during the 2.5 day meetings. We describe the best methods of surveillance in general, the stakeholders in dengue surveillance, and the steps from mosquito bite to reporting of a dengue case to explore how best to carry out dengue surveillance. We also provide details and a comparison of the dengue surveillance programs by the presenting countries. Conclusions/Significance The experts provided recommendations for achieving the best possible data from dengue surveillance accepting the realities of the real world (e.g., limited funding and staff). Their recommendations included: (1) Every dengue endemic country should make reporting of dengue cases to the government mandatory; (2) electronic reporting systems should be developed and used; (3) at minimum dengue surveillance data should include incidence, hospitalization rates, deaths by age group; (4) additional studies should be completed to check the sensitivity of the system; (5) laboratories should share expertise and data; (6) tests that identify dengue virus should be used in patients with fever for four days or less and antibody tests should be used after day 4 to diagnose dengue; and (7) early detection and prediction of dengue outbreaks should be goals for national surveillance systems.
Beatty, Mark E.; Stone, Amy; Fitzsimons, David W.; Hanna, Jeffrey N.; Lam, Sai Kit; Vong, Sirenda; Guzman, Maria G.; Mendez-Galvan, Jorge F.; Halstead, Scott B.; Letson, G. William; Kuritsky, Joel; Mahoney, Richard; Margolis, Harold S.
Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (DF, dengue fever) to the more severe forms of hemorrhagic fever/dengue shock syndrome (DHF/DSS). The aim of this study was the serological and molecular confirmation of an outbreak of dengue in Falcon state, Venezuela. A total of 54 sera from patients with clinical diagnosis of DV infection were analyzed by an enzyme immunoassays developed in Venezuela (ELISA -IgM e -IgG) and by PCR. From them, 78% exhibited DV infection (PCR+ y/o IgM+), 48% exhibited viremia by PCR and 57% were positive to IgM. An interesting observation was the high percent (76%) of patients with past or secondary infection (IgG positive), which included all the patients exhibiting clinical symptoms of DHF (n = 8). From the PCR positive sera, serotype 1 was found in 27%, serotype 2 in 54% and serotype 4 in 19%. No serotype 3 was found circulating in this population, although this serotype was already circulating in the nearby island of Aruba. The combination of serological and molecular methods allow us to obtain a fairly precise information of this outbreak. PMID:14552060
Moros, Zoila Caridad; Abad, María Jesús; Arsenak, Miriam; Martínez, Dilia; Cierco, Maria Magdalena; Costagliola, Asunta; Urbina, Leyda; Taylor, Peter; Liprandi, Ferdinando; Pujol, Flor Helene
Since 2001, three autochthonous dengue fever outbreaks have occurred in the United States: in Hawaii (2001); Brownsville, Texas (2005); and southern Florida (2009–2011). We sought to characterize and describe the response to these outbreaks from the perspectives of public health and vector control officials. By conducting a medical literature review through PubMed and news media searches through Google, we identified persons involved in managing each outbreak; 26 persons then participated in qualitative, semistructured interviews. After analyzing the 3 outbreaks, we found the following prominent themes in the response efforts: timely detection of illness; communication of up-to-date, correct information; and development of a rapid response that engages the community. We therefore recommend that public health authorities involve the clinical and laboratory community promptly, provide accurate information, and engage the local community in vector control and case identification and reporting.
Sell, Tara Kirk; Bouri, Nidhi; Franco, Crystal
A large outbreak of dengue virus (DV) infections occurred on Caribbean islands during 2010, with cases peaking during the second half of the year. In conjunction with the outbreak, we observed an unprecedented spike in the number of sera submitted for DV antibody testing between June and December 2010, with a concomitant increase in the number of IgM-positive specimens, indicative of acute DV infection. Analysis of the place of residence of the IgM-positive patients identified from June to December of 2010 revealed that 58.1% were residents of Caribbean islands (Puerto Rico and the U.S. Virgin Islands), whereas 40.6% were residents of the U.S. mainland or Hawaii. The U.S. residents represented 42 states plus the District of Columbia, but most (53%) were from just 3 states (California, Florida, and New York). In comparison to the Caribbean IgM-positive patient group, the U.S. IgM-positive patient group contained proportionately more adults 21 to 60 years old and fewer individuals <21 years old. These findings indicate that the 2010 Caribbean DV outbreak affected many U.S. residents (mostly adults, presumably travelers) from diverse geographic areas and emphasize the potential for a viremic DV-infected returning traveler to spark a local DV outbreak by introducing DV into a community with competent mosquito vectors.
Prince, Harry E.; Matud, Jose L.; Lieberman, Jay M.
Background In 2009, an outbreak of dengue caused high fatality in Sri Lanka. We conducted 5 autopsies of clinically suspected myocarditis cases at the General Hospital, Peradeniya to describe the histopathology of the heart and other organs. Methods The diagnosis of dengue was confirmed with specific IgM and IgG ELISA, HAI and RT-PCR techniques. The histology was done in tissue sections stained with hematoxylin and eosin. Results Of the 319 cases of dengue fever, 166(52%) had severe infection. Of them, 149 patients (90%) had secondary dengue infection and in 5 patients, DEN-1 was identified as the causative serotype. The clinical diagnosis of myocarditis was considered in 45(27%) patients. The autopsies were done in 5 patients who succumbed to shock (3 females and 2 males) aged 13- 31 years. All had pleural effusions, ascites, bleeding patches in tissue planes and histological evidence of myocarditis. The main histological findings of the heart were interstitial oedema with inflammatory cell infiltration and necrosis of myocardial fibers. One patient had pericarditis. The concurrent pulmonary abnormalities were septal congestion, pulmonary haemorrhage and diffuse alveolar damage; one case showed massive necrosis of liver. Conclusions The histology supports occurrence of myocarditis in dengue infection.
|One strain of E. coli is not usually found in foods, but has been related to consumption of undercooked ground beef. Symptoms are stomach cramps and diarrhea, and 2-7% of infections lead to hemolytic uremic syndrome, which is life threatening. Camps can prevent outbreaks by avoiding uncooked meat on overnight campouts and requiring appropriate…
McKinney, Mary D.
The government of Thailand has invested heavily in community-based dengue fever prevention campaigns, yet community participation has been inadequate to prevent transmission. This ethnographic study explored local understandings of dengue in rural northeast Thailand, and their implications for adherence to government-initiated prevention measures centred around mosquito control. While community members recognised the most severe manifestation of the disease – dengue
Dengue is the most important vector-borne disease in the Americas and threatens the lifes of millions of people in developing countries. Imprecise morbidity and mortality statistics underestimate the magnitude of dengue as a regional health problem. As a result, it is considered a low priority by the health sector with no timely steps for effective control. Dengue is perceived as a problem of 'others' (individually, collectively and institutionally), therefore responsibility for its control is passed on to others (neighbors, the community, municipality, health institutions, or other governmental agencies). With no precise risk indicators available there is little opportunity for timely diagnoses, treatment, health interventions or vector control (poor surveillance). Solutions only targeting the vector reduce the impact of interventions and there is no sustainable control. Without political commitment there are insufficient resources to face the problem. This paper discusses the challenges for prevention and control in the Americas. PMID:19287863
Gómez-Dantés, Héctor; Willoquet, Janine Ramsey
Dengue infection (DI) is a major health problem in Thailand and is especially prevalent in Ubon Ratchathani Province. The objectives of the project were: (1) to develop a geo-database system for DI prevention and control, (2) to perform an Aedes aegypti larval vector survey for DI prevention and control in Ubon Ratchathani Province, (3) to study the behavior and perceptions regarding DI prevention among the target population in Ubon Ratchathani Province. Ten villages with high incidences of DI over a 3 year period from 2005 to 2007 were selected. The survey was divided into 2 periods, pre-outbreak period (February-April 2008) and outbreak period (June-August 2008). The data were collected in April and June 2008. The households in each village were purposively sampled. Water containers inside and outside of the houses were surveyed using the World Health Organization's house index (HI), container index (CI), and Breteau index (BI). The location of each household was recorded using the global positioning system (GPS). Data regarding people's perceptions and behaviors concerning DI prevention were collected during interviews of 383 families in Mach 2008. A database for DI was developed using ArcView version 9.2. The results showed during the pre-outbreak period, Non Jig, Non Sawang, and Huai Teeneu villages had the highest risk level (BI > or =50). During the outbreak period, Non Jig and Huai Teeneu village had the highest risk level (BI > or =50). Results regarding DI perceptions showed the target population had high levels of DI perceptions. DI preventive behavior was found in 50.9%. PMID:21073058
Wongbutdee, Jaruwan; Chaikoolvatana, Anun; Saengnill, Wacharapong; Krasuaythong, Nantaya; Phuphak, Surajit
An unprecedented dengue outbreak occurred in 2010 in Port Sudan city, Sudan. Dengue incidence was 94 cases per 10 000 observed over 17 epidemiological weeks (total cases = 3 765). We report here the impact of the vector control response plan to the outbreak, which mainly entailed house inspection and insecticide space spraying. In total 3 048 houses were inspected during vector surveillance and 19 794 larvae and 3 240 pupae of Aedes aegypti were collected. Entomological indices decreased during the period: house index declined from 100% to 16% (F= 57.8, P < 0.001) and pupal/person (P/P) index from 0.77 to 0.10 (F= 3.06, P < 0.01) in weeks 9 and 21 respectively. This decline was accompanied by a decrease in cases from a peak of 341 cases in week 13 to zero in week 29 and the end of the outbreak. There was a significant correlation between the entomological parameters and dengue incidence (R2 = 0.83, F= 23.9, P < 0.001). Integrated epidemiological and vector surveillance is essential to an effective dengue control programme PMID:23301396
Seidahmed, O M E; Siam, H A M; Soghaier, M A; Abubakr, M; Osman, H A; Abd Elrhman, L S; Elmagbol, B; Velayudhan, R
In October 2009, two-3 months after an outbreak of a febrile disease with joint pain on the eastern coast of Madagascar, we assessed serologic markers for chikungunya virus (CHIKV), dengue virus (DENV), and Rift Valley fever virus (RVFV) in 1,244 pregnant women at 6 locations. In 2 eastern coast towns, IgG seroprevalence against CHIKV was 45% and 23%; IgM seroprevalence was 28% and 5%. IgG seroprevalence against DENV was 17% and 11%. No anti-DENV IgM was detected. At 4 locations, 450-1,300 m high, IgG seroprevalence against CHIKV was 0%-3%, suggesting CHIKV had not spread to higher inland-altitudes. Four women had IgG against RVFV, probably antibodies from a 2008 epidemic. Most (78%) women from coastal locations with CHIKV-specific IgG reported joint pain and stiffness; 21% reported no symptoms. CHIKV infection was significantly associated with high bodyweight. The outbreak was an isolated CHIKV epidemic without relevant DENV co-transmission. PMID:23092548
Schwarz, Norbert G; Girmann, Mirko; Randriamampionona, Njary; Bialonski, Alexandra; Maus, Deborah; Krefis, Anne Caroline; Njarasoa, Christine; Rajanalison, Jeanne Fleury; Ramandrisoa, Herly Daniel; Randriarison, Maurice Lucien; May, Jürgen; Schmidt-Chanasit, Jonas; Rakotozandrindrainy, Raphael
BackgroundBecause no dengue vaccine or antiviral therapy is commercially available, controlling the primary mosquito vector, Aedes aegypti, is currently the only means to prevent dengue outbreaks. Traditional models of Ae. aegypti assume that population dynamics are regulated by density-dependent larval competition for food and little affected by oviposition behavior. Due to direct impacts on offspring survival and development, however, mosquito
Jacklyn Wong; Steven T. Stoddard; Helvio Astete; Amy C. Morrison; Thomas W. Scott
Objectives To study the significance of entomological surveillance, the house index (HI), container index (CI), and Breteau index (BI) were determined to estimate the degree of a major dengue outbreak in Tirunelveli, Tamil Nadu, India (Latitude: 8°42?N; Longitude: 77°42?E) in May 2012. Methods The HI, CI, and BI were determined in a primary health center (PHC) in the village of Maruthamputhur (Pappakudi taluk, Tirunelveli) by carrying out an antilarval (AL) work that involved door-to-door search for immature stages of Aedes spp. mosquitoes by trained field workers and volunteers. The work of field workers was evaluated by a junior and senior entomologist the following day. Results Before the AL work, the reported numbers of fever cases from Week 1 to 5 in Maruthamputhur were 211, 394, 244, 222, and 144 with two deaths. By contrast, after the AL work, these numbers were considerably reduced and there was no fever-related death (the HI was reduced from 48.2% to 1.6%, the CI from 28.6% to 0.4%, and the BI from 48.2 to 1.6). Conclusion Because no specific medicine and vaccines are available to treat dengue fever and dengue hemorrhagic fever, entomological surveillance and its significance can be used to halt the outbreak of dengue as shown in this study.
Basker, Parasuraman; Kannan, Pichai; Porkaipandian, Rajagopal Thirugnanasambandam; Saravanan, Sivsankaran; Sridharan, Subramaniam; Kadhiresan, Mahaligam
Background Since the first reported outbreak of dengue hemorrhagic fever in Pakistan, several mini outbreaks have erupted in the region. Dengue virus serotype 3 (DEN-3) was first documented in 2005 outbreak in Karachi. Reports show that serotype 3 is prevalent in Lahore since 2008. Serotype 2 (DEN-2) is the major circulating serotype in Pakistan as it is documented since 1994. We have conducted a detailed study of three outbreaks of dengue virus infection that occurred in years 2007, 2008 and 2009 in Lahore by using molecular techniques such as PCR and nucleotide sequencing of the C-prM gene junction of Dengue virus. Results Through the analysis of 114 serum samples collected over the period of three years (2007-2009), total 20 patients were found to be infected with dengue virus. In year 2007, four were positive for serotype 2 and one sample was positive for serotype DEN-3. In 2008, five samples had concurrent infection with serotypes DEN-2 and DEN-3 while three samples were infected only with serotype DEN-2. In year 2009, one sample had concurrent infection with serotypes DEN-2 and DEN-3 while six were positive for serotype DEN-2 only. Conclusions Our study showed that serotype DEN-2 was dominant in positive samples of dengue virus infection collected during the period of three years (2007-2009). The other serotype present was serotype DEN-3. Genotypes of serotype DEN-2 and serotype DEN-3 were subtype IV and subtype III, respectively.
In 2010, a large outbreak of dengue occurred in Santos, Brazil. The detection of the NS1 antigen was used for diagnosis in addition to the detection of IgG, IgM, and RNA. A large number of NS1 false-negative results were obtained. A total of 379 RNA-positive samples were selected for thorough evaluation. NS1 was reactive in 37.7% of cases. Most of the cases were characterized as a secondary infection by dengue 2 virus. Sequencing of NS1 positive and negative isolates did not reveal any mutation that could justify the diagnostic failure. Use of existing NS1 tests in the Brazilian population may present a low negative predictive value, and they should be used with caution, preferentially after performing a validation with samples freshly obtained during the ongoing epidemic.
Felix, Alvina Clara; Romano, Camila Malta; Centrone, Cristiane de Campos; Rodrigues, Celia Lima; Villas-Boas, Lucy; Araujo, Evaldo Stanislau; de Matos, Andreia Manso; Carvalho, Karina Inacio; Martelli, Celina Maria Turchi; Kallas, Esper Georges; Pannuti, Claudio Sergio
Dengue fever and dengue haemorrhagic fever are important arthropod-borne viral diseases. Each year, there are ?50 million dengue infections and ?500,000 individuals are hospitalized with dengue haemorrhagic fever, mainly in Southeast Asia, the Pacific and the Americas. Illness is produced by any of the four dengue virus serotypes. A global strategy aimed at increasing the capacity for surveillance and outbreak
Maria G. Guzman; Scott B. Halstead; Harvey Artsob; Philippe Buchy; Jeremy Farrar; Duane J. Gubler; Elizabeth Hunsperger; Axel Kroeger; Harold S. Margolis; Eric Martínez; Michael B. Nathan; Jose Luis Pelegrino; Cameron Simmons; Sutee Yoksan; Rosanna W. Peeling
Background The re-emergence of dengue virus 4 (DENV-4) has become a public health concern in South America, Southeast Asia and South Asia. However, it has not been known to have caused a local outbreak in China for the past 20 years. The purpose of this study was to elucidate the epidemiology of one local community outbreak caused by DENV-4 in Guangzhou city, China, in 2010; and to determine the molecular characteristics of the genotype II virus involved. Case presentations During September and October of 2010, one imported case, a Guangzhou resident who travelled back from Thailand, resulted in 18 secondary autochthonous cases in Guangzhou City, with an incidence rate of 5.53 per 10,000 residents. In indigenous cases, 14 serum samples tested positive for IgM against DENV and 7 for IgG from a total of 15 submitted serum samples, accompanied by 5 DENV-4 isolates. With identical envelope gene nucleotide sequences, the two isolates (D10168-GZ from the imported index case and Guangzhou 10660 from the first isolate in the autochthonous cases) were grouped into DENV-4 genotype II after comparison to 32 previous DENV-4 isolates from GenBank that originated from different areas. Conclusions Based on epidemiological and phylogenetic analyses, the outbreak, which was absent for 20 years after the DENV-4 genotype I outbreak in 1990, was confirmed as DENV-4 genotype II and initially traced to the imported index case, a Guangzhou resident who travelled back from Thailand.
WHO recommends that 70% of dogs in a population should be immunized to eliminate or prevent outbreaks of rabies. This critical percentage (pc) has been established empirically from observations on the relationship between vaccination coverage and rabies incidence in dog populations around the world. Here, by contrast, we estimate pc by using epidemic theory, together with data available from four
Paul G. Coleman; Christopher Dye
Kaohsiung City, a modern metropolis of 1.5 million persons, has been the focus of dengue virus activity in Taiwan for several decades. The aim of this study was to provide a temporal and spatial description of dengue virus epidemiology in Kaohsiung City by using data for all laboratory-confirmed dengue cases during 2003–2009. We investigated age- and sex-dependent incidence rates and the spatiotemporal patterns of all cases confirmed through passive or active surveillance. Elderly persons were at particularly high risk for dengue virus–related sickness and death. Of all confirmed cases, ?75% were detected through passive surveillance activities; case-patients detected through active surveillance included immediate family members, neighbors, and colleagues of confirmed case-patients. Changing patterns of case clustering could be due to the effect of unmeasured environmental and demographic factors.
Schi?ler, Karin L.; Jepsen, Martin R.; Ho, Chi-Kung; Li, Shu-Hua; Konradsen, Flemming
In the course of entomologic studies conducted on Koh Samui during 1966 both Aedes aegypti and Aedes albopictus were implicated in the transmission of dengue viruses on that island. Both species were widely distributed and abundant during the 1966 epidemi...
D. J. Gould T. M. Yuill M. A. Moussa P. Simasathien L. C. Rutledge
...Norovirus Gastroenteritis Outbreaks in Healthcare Settings AGENCY: Centers for Disease...Norovirus Gastroenteritis Outbreaks in Healthcare Settings, available on the following...use by infection prevention staff, healthcare epidemiologists, healthcare...
In the French West Indies (Martinique, Guadeloupe and French Guyana), dengue represents a model of a reemerging arbovirosis, with hyperendemicity and more severe cases and deaths than previously observed Co-circulation of the four serotypes, the increasing number of cases during interepidemic periods, and the increase in severe forms (particularly hemorrhagic forms), are signs of forthcoming hyperendemicity. DEN-2 is the viral subtype most frequently associated with severe forms. Other arboviroses, like West Nile disease and chikungunya, overflowing from their usual geographical areas and with the potential to cause hemorrhagic syndromes and encephalitis, have emerged or reemerged in tropical zones of Africa, Asia, America and the Indian Ocean, but also in temperate areas of northern America and southern Europe. The risk of imported arboviroses, particularly dengue and chikungunya, is a real threat in temperate countries, including southern France, where Aedes albopictus, a vector mosquito, is present. PMID:19024949
The dengue virus has a single-stranded positive-sense RNA genome of ?10.700 nucleotides with a single open reading frame that encodes three structural (C, prM, and E) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. It possesses four antigenically distinct serotypes (DENV 1–4). Many phylogenetic studies address particularities of the different serotypes using convenience samples that are
Adriano Mondini; Roberta Vieira de Moraes Bronzoni; Silvia Helena Pereira Nunes; Francisco Chiaravalloti Neto; Eduardo Massad; Wladimir J. Alonso; Eduardo S. M. Lázzaro; Amena Alcântara Ferraz; Paolo Marinho de Andrade Zanotto; Maurício Lacerda Nogueira
We got one of the most significant epidemics of the history of Dengue in Puerto Rico despite all major educational efforts made. The objective is to determine how much knowledge the people have about the prevention and transmission of Dengue virus. We administered a questionnaire of fifteen questions to 140 people of different communities at the metropolitan area as well as in the East area of Puerto Rico during the months of September to November of 2012. 88% were adults, 100 were women and 40 men. The majority was from Caguas, Carolina, San Juan, and Bayamon. 60% were professionals. One hundred percent knew what Dengue is and 90% knows the mosquito. 77% of the participants know the actual epidemics, but the men got a 10% higher knowledge than women on the subject. Around 47% are not prepared to fight the Dengue virus, but they have great knowledge about the preventive measures and the clinical Management of Dengue Syndrome. 66% did not know that Puerto Rico has a Dengue Center from the CDC located at the Island. Only 17.5% of the participants knows that the Dengue Virus can be transmitted through transfusion of blood components. Our study met our objectives showing that we have good knowledge about Dengue, but there is poor knowledge about the transmission of Dengue Virus through transfusion of blood components. There is a big necessity to develop community strategies to eliminate this disease. We recommend repeating this study with more collaboration from other entities, more questions, and more participants. PMID:23882986
Rodríguez, Ian J Rivera; Rivera, Augusto A Puig; Morales-Borges, Raúl H
We describe an outbreak of Legionnaires' disease in 2006 in Amsterdam, the Netherlands. Comparisons with the outbreak that took place in 1999 are made to evaluate changes in legionella prevention and outbreak management. The 2006 outbreak was caused by a wet cooling tower. Thirty-one patients were reported. The outbreak was detected two days after the first patient was admitted to hospital, and the source was eliminated five days later. The 1999 outbreak was caused by a whirlpool at a flower show, and 188 patients were reported. This outbreak was detected 14 days after the first patient was admitted to hospital, and two days later the source was traced. Since 1999, the awareness of legionellosis among physicians, the availability of a urinary antigen tests and more efficient early warning and communication systems improved the efficiency of legionellosis outbreak management. For prevention, extensive legislation with clear responsibilities has been put in place. For wet cooling towers, however, legislation regarding responsibility and supervision of maintenance needs to be improved. PMID:18801319
Sonder, G J; van den Hoek, J A; Bovée, L P; Aanhane, F E; Worp, J; Du Ry van Beest Holle, M; van Steenbergen, J E; den Boer, J W; Ijzerman, E P; Coutinho, R A
Dengue virus currently causes 50-100 million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3(DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008 respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of 7 amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may give additional insight into the adaptive response of DENV-3 at the population level.
Schmidt, DJ; Pickett, BE; Camacho, D; Comach, G; Xhaja, K; Lennon, NJ; Rizzolo, K; de Bosch, N; Becerra, A; Nogueira, ML; Mondini, A; da Silva, EV; Vasconcelos, PF; Munoz-Jordan, JL; Santiago, GA; Ocazionez, R; Gehrke, L; Lefkowitz, EJ; Birren, BW; Henn, MR; Bosch, I
The dengue virus has a single-stranded positive-sense RNA genome of approximately 10.700 nucleotides with a single open reading frame that encodes three structural (C, prM, and E) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. It possesses four antigenically distinct serotypes (DENV 1-4). Many phylogenetic studies address particularities of the different serotypes using convenience samples that are not conducive to a spatio-temporal analysis in a single urban setting. We describe the pattern of spread of distinct lineages of DENV-3 circulating in São José do Rio Preto, Brazil, during 2006. Blood samples from patients presenting dengue-like symptoms were collected for DENV testing. We performed M-N-PCR using primers based on NS5 for virus detection and identification. The fragments were purified from PCR mixtures and sequenced. The positive dengue cases were geo-coded. To type the sequenced samples, 52 reference sequences were aligned. The dataset generated was used for iterative phylogenetic reconstruction with the maximum likelihood criterion. The best demographic model, the rate of growth, rate of evolutionary change, and Time to Most Recent Common Ancestor (TMRCA) were estimated. The basic reproductive rate during the epidemics was estimated. We obtained sequences from 82 patients among 174 blood samples. We were able to geo-code 46 sequences. The alignment generated a 399-nucleotide-long dataset with 134 taxa. The phylogenetic analysis indicated that all samples were of DENV-3 and related to strains circulating on the isle of Martinique in 2000-2001. Sixty DENV-3 from São José do Rio Preto formed a monophyletic group (lineage 1), closely related to the remaining 22 isolates (lineage 2). We assumed that these lineages appeared before 2006 in different occasions. By transforming the inferred exponential growth rates into the basic reproductive rate, we obtained values for lineage 1 of R(0) = 1.53 and values for lineage 2 of R(0) = 1.13. Under the exponential model, TMRCA of lineage 1 dated 1 year and lineage 2 dated 3.4 years before the last sampling. The possibility of inferring the spatio-temporal dynamics from genetic data has been generally little explored, and it may shed light on DENV circulation. The use of both geographic and temporally structured phylogenetic data provided a detailed view on the spread of at least two dengue viral strains in a populated urban area. PMID:19478848
Mondini, Adriano; de Moraes Bronzoni, Roberta Vieira; Nunes, Silvia Helena Pereira; Chiaravalloti Neto, Francisco; Massad, Eduardo; Alonso, Wladimir J; Lázzaro, Eduardo S M; Ferraz, Amena Alcântara; de Andrade Zanotto, Paolo Marinho; Nogueira, Maurício Lacerda
During 1990, Dengue-2 (DEN-2) virus was isolated for the first time from mosquitoes (Aedes furcifer, six isolates; Ae. taylori, six isolates; Ae. luteocephalus, seven isolates) collected during an epidemic in which DEN-2 virus also was isolated from humans. Numerous isolations have been made previously from mosquitoes in the absence of human infection. In Senegal, DEN-2 virus appears to be maintained in an enzootic cycle and, therefore, plays an expanding role in human disease and increases the need for effective surveillance in mosquito populations. PMID:7932611
Traore-Lamizana, M; Zeller, H; Monlun, E; Mondo, M; Hervy, J P; Adam, F; Digoutte, J P
Dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. In 1998 this mosquito-borne disease is the most important tropical infectious disease after malaria, with an estimated 100 million cases of dengue fever, 500,000 cases of dengue hemorrhagic fever, and 25,000 deaths annually. The reasons for this resurgence and emergence of dengue hemorrhagic fever in the waning years of the 20th century are complex and not fully understood, but demographic, societal, and public health infrastructure changes in the past 30 years have contributed greatly. This paper reviews the changing epidemiology of dengue and dengue hemorrhagic fever by geographic region, the natural history and transmission cycles, clinical diagnosis of both dengue fever and dengue hemorrhagic fever, serologic and virologic laboratory diagnoses, pathogenesis, surveillance, prevention, and control. A major challenge for public health officials in all tropical areas of the world is to devleop and implement sustainable prevention and control programs that will reverse the trend of emergent dengue hemorrhagic fever.
Gubler, Duane J.
Since mid 95, many Caribbean islands and America's countries suffer from a new outbreak of an epidemic of dengue fever and dengue haemorrhagic fever. Until today, no case of dengue haemorrhagic fever was reported in Martinique (FWI) in spite of the high prevalence of dengue fever in the island. The first identified case asserts the severity of illness. In Martinique, these arbovirosis is often underestimated. Nowadays, the disease prevention must become one of the principal targets of the medical corporation and the Public Health Authorities. Consequently, epidemiologic survey and principally vector's control must be reinforced. PMID:9053042
Mansuy, J M; Delor, R; Mehdaoui, H; Elizabeth, L
\\u000a The transition from prescribed to adapted dengue prevention will need to be guided by meaningful goals and accomplished with\\u000a effective tools. Goals will be reached if enhanced vector control is framed by an improved understanding of vector ecology\\u000a in pathogen transmission. Longitudinal field studies that capture entomologic, virologic, and epidemiologic information are\\u000a the most effective was to assess fundamental assumptions
Thomas W. Scott; Amy C. Morrison
In 2001, a major dengue outbreak was recorded in Chennai city, with 737 cases (90%) out of a total of 861 cases recorded from Tamil Nadu state. A KAP survey was carried out to assess the community knowledge, attitude and practice on dengue fever (DF), following the major dengue outbreak in 2001. A pre- tested, structured questionnaire was used for data collection. The multistage cluster sampling method was employed and 640 households (HHs) were surveyed. Among the total HHs surveyed, 34.5% of HHs were aware of dengue and only 3.3% of HHs knew that virus is the causative agent for DF. Majority of the HHs (86.5%) practiced water storage and only 3% of them stored water more than 5 days. No control measures were followed to avoid mosquito breeding in the water holding containers by majority of HHs (65%). Sixty percent of HHs did not know the biting behaviour of dengue vector mosquitoes. The survey results indicate that the community knowledge was very poor on dengue, its transmission, vector breeding sources, biting behavior and preventive measures. The lack of basic knowledge of the community on dengue epidemiology and vector bionomics would be also a major cause of increasing trend of dengue in this highly populated urban environment. There is an inevitable need to organize health education programmes about dengue disease to increase community knowledge and also to sensitize the community to participate in integrated vector control programme to resolve the dengue problem. PMID:20962733
Ashok Kumar, V; Rajendran, R; Manavalan, R; Tewari, S C; Arunachalam, N; Ayanar, K; Krishnamoorthi, R; Tyagi, B K
An outbreak of dengue fever (DF), dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS) in the city of Palembang, south Sumatra, Indonesia was investigated to (i) validate epidemic occurrence, (ii) confirm dengue virus aetiology and associated serotype(s), (iii) provide a demonstrable measure of community impact, and (iv) identify causative relationship (if any) with climatic El Niño Southern Oscillation (ENSO)
Andrew Lee Corwin; Ria Purwita Larasati; Michael J. Bangs; Suharyono Wuryadi; Sumarjati Arjoso; Nono Sukri; Erlin Listyaningsih; Sri Hartati; Rozali Namursa; Zarkasih Anwar; Surya Chandra; Benny Loho; Holani Ahmad; James R. Campbell; Kevin R. Porter
Outbreak! is an online, interactive educational game that helps students and teachers learn and evaluate clinical microbiology skills. When the game was used in introductory microbiology laboratories, qualitative evaluation by students showed very positiv
Smith, Geoffrey B.; Clark, Sherri
Background Although dengue is endemic in Puerto Rico (PR), 2007 and 2010 were recognized as epidemic years. In the continental United States (US), outside of the Texas-Mexico border, there had not been a dengue outbreak since 1946 until dengue re-emerged in Key West, Florida (FL), in 2009–2010. The objective of this study was to use electronic and manual surveillance systems to identify dengue cases in Veterans Affairs (VA) healthcare facilities and then to clinically compare dengue cases in Veterans presenting for care in PR and in FL. Methodology Outpatient encounters from 1/2007–12/2010 and inpatient admissions (only available from 10/2009–12/2010) with dengue diagnostic codes at all VA facilities were identified using VA's Electronic Surveillance System for Early Notification of Community-based Epidemics (ESSENCE). Additional case sources included VA data from Centers for Disease Control and Prevention BioSense and VA infection preventionists. Case reviews were performed. Categorical data was compared using Mantel-Haenszel or Fisher Exact tests and continuous variables using t-tests. Dengue case residence was mapped. Findings Two hundred eighty-eight and 21 PR and FL dengue cases respectively were identified. Of 21 FL cases, 12 were exposed in Key West and 9 were imported. During epidemic years, FL cases had significantly increased dengue testing and intensive care admissions, but lower hospitalization rates and headache or eye pain symptoms compared to PR cases. There were no significant differences in clinical symptoms, laboratory abnormalities or outcomes between epidemic and non-epidemic year cases in FL and PR. Confirmed/probable cases were significantly more likely to be hospitalized and have thrombocytopenia or leukopenia compared to suspected cases. Conclusions Dengue re-introduction in the continental US warrants increased dengue surveillance and education in VA. Throughout VA, under-testing of suspected cases highlights the need to emphasize use of diagnostic testing to better understand the magnitude of dengue among Veterans.
Schirmer, Patricia L.; Lucero-Obusan, Cynthia A.; Benoit, Stephen R.; Santiago, Luis M.; Stanek, Danielle; Dey, Achintya; Martinez, Mirsonia; Oda, Gina; Holodniy, Mark
Outbreaks of infection with multi-resistant microorganisms are an increasing problem in intensive care units. Such outbreaks\\u000a lead to increased mortality, longer duration of stay, higher costs and reduced availability of ICU beds [1, 2]. Many guidelines advocate strict adherence to hygiene measures, patient isolation and antibiotic restriction, but in spite\\u000a of good and sometimes even supervised adherence to these measures,
Hans I. van der Spoel; Rik T. Gerritsen
A cross-sectional survey was conducted to assess the knowledge, attitudes about, and practices to prevent, dengue fever among Myanmar migrant woman caretakers in Mae Sot District, Tak Province, Thailand during January 2004. In total, 307 households out of 1,014 Myanmar migrant households in Mae Sot District were selected using systematic random sampling. One woman caretaker per household was interviewed using
Hmwe Hmwe Kyu; Myint Thu; Marc Van der Putten
Dengue infection is a major public health problem, affecting children in the Southeast Asia region. In Thailand, the dengue hemorrhagic fever is still a major infectious disease among the children with up to two to three epidemics per year. Hemoconcentration accompanied by platelet depletion are the predominant laboratory signs of dengue hemorrhagic fever. Findings from 23 hospitalized patients with dengue
Viroj Wiwanitkit; Pornake Manusvanich
De novo guidance on the management of Gram-negative bacteria outbreaks in UK neonatal units was developed in 2012 by a Department of Health, England Antimicrobial Resistance and Healthcare Associated Infection working group. The recommendations included activation of an organisational response and establishing a control team when an outbreak is suspected; screening for the specific organism only during an outbreak; undertaking multidisciplinary reviews of cleaning routines, hand hygiene and Gram-negative bacteria transmission risks; considering deep-cleaning; cohorting colonised and infected babies preferably but not necessarily in isolation cubicles; and considering reducing beds or closing a unit to new admissions as a way of improving spacing and staff:patient ratios until the outbreak is under control. The group advised establishing mechanisms to communicate effectively across the network; informing parents of the outbreak as early as possible, and providing prewritten 'infection outbreak' information sheets. For prevention of outbreaks, the group advised meeting national staffing and cot-spacing requirements; following a Water Action Plan; using infection reduction care bundles and benchmarking; and introducing breast milk early and limiting antibiotic use. PMID:23792354
Anthony, Mark; Bedford-Russell, Alison; Cooper, Tracey; Fry, Carole; Heath, Paul T; Kennea, Nigel; McCartney, Maureen; Patel, Bharat; Pollard, Tina; Sharland, Mike; Wilson, Peter
Background During the last decades, dengue viruses have spread throughout the Americas region, with an increase in the number of severe forms of dengue. The surveillance system in Guadeloupe (French West Indies) is currently operational for the detection of early outbreaks of dengue. The goal of the study was to improve this surveillance system by assessing a modelling tool to predict the occurrence of dengue epidemics few months ahead and thus to help an efficient dengue control. Methods The Box-Jenkins approach allowed us to fit a Seasonal Autoregressive Integrated Moving Average (SARIMA) model of dengue incidence from 2000 to 2006 using clinical suspected cases. Then, this model was used for calculating dengue incidence for the year 2007 compared with observed data, using three different approaches: 1 year-ahead, 3 months-ahead and 1 month-ahead. Finally, we assessed the impact of meteorological variables (rainfall, temperature and relative humidity) on the prediction of dengue incidence and outbreaks, incorporating them in the model fitting the best. Results The 3 months-ahead approach was the most appropriate for an effective and operational public health response, and the most accurate (Root Mean Square Error, RMSE = 0.85). Relative humidity at lag-7 weeks, minimum temperature at lag-5 weeks and average temperature at lag-11 weeks were variables the most positively correlated to dengue incidence in Guadeloupe, meanwhile rainfall was not. The predictive power of SARIMA models was enhanced by the inclusion of climatic variables as external regressors to forecast the year 2007. Temperature significantly affected the model for better dengue incidence forecasting (p-value = 0.03 for minimum temperature lag-5, p-value = 0.02 for average temperature lag-11) but not humidity. Minimum temperature at lag-5 weeks was the best climatic variable for predicting dengue outbreaks (RMSE = 0.72). Conclusion Temperature improves dengue outbreaks forecasts better than humidity and rainfall. SARIMA models using climatic data as independent variables could be easily incorporated into an early (3 months-ahead) and reliably monitoring system of dengue outbreaks. This approach which is practicable for a surveillance system has public health implications in helping the prediction of dengue epidemic and therefore the timely appropriate and efficient implementation of prevention activities.
This study analyzed the association between household-level ecologic and individual-level sociodemographic determinants and dengue transmission in urban areas of Chachoengsao province, Thailand. The ecologic and sociodemographic variables were examined by univariate analysis and multivariate logistic regression. In the ecologic model, dengue risk was related to households situated in the ecotope of residential mixed with commercial and densely populated urban residential areas (RCDENPURA) (aOR?=?2.23, P = 0.009), high historical dengue risk area (aOR?=?2.06, P < 0.001), and presence of household window screens (aOR?=?1.62, P = 0.023). In the sociodemographic model, the dengue risk was related to householders aged >45 years (aOR?=?3.24, P = 0.003), secondary and higher educational degrees (aOR?=?2.33, P = 0.013), household members >4 persons (aOR?=?2.01, P = 0.02), and community effort in environmental management by clean-up campaign (aOR?=?1.91, P = 0.035). It is possible that the preventive measures were positively correlated with dengue risk because these activities were generally carried out in particular households or communities following dengue experiences or dengue outbreaks. Interestingly, the ecotope of RCDENPURA and high historical dengue risk area appeared to be very good predictors of dengue incidences.
Koyadun, Surachart; Butraporn, Piyarat; Kittayapong, Pattamaporn
Local transmission of dengue fever virus in Argentina is increased by the presence of Aedes aegypti mosquitoes and dengue outbreaks in neighboring countries. From 1995 to 2001, a laboratory-based active surveillance program detected 922 dengue cases. Indigenous transmission involving dengue-1 and -2 serotypes was confirmed only in subtropical areas in northern Argentina.
Paz, Maria Valeria; Rangeon, Griselda; Ranaivoarisoa, Marie Y.; Verzeri, Nora; Roginski, Sandra; Baroni, Pablo; Enria, Delia
|Background: Dengue fever and dengue hemorrhagic fever (DF/DHF) are epidemic and endemic in tropical and subtropical countries including Sri Lanka. Numerous structural and community interventions have been shown to be effective in interrupting the life cycle of mosquitoes that transmit DF/DHF; however, these interventions are not always…
Jayawardene, Wasantha P.; Lohrmann, David K.; YoussefAgha, Ahmed H.; Nilwala, Dayani C.
The dengue virus has a single-stranded positive-sense RNA genome of ?10.700 nucleotides with a single open reading frame that encodes three structural (C, prM, and E) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. It possesses four antigenically distinct serotypes (DENV 1–4). Many phylogenetic studies address particularities of the different serotypes using convenience samples that are not conducive to a spatio-temporal analysis in a single urban setting. We describe the pattern of spread of distinct lineages of DENV-3 circulating in São José do Rio Preto, Brazil, during 2006. Blood samples from patients presenting dengue-like symptoms were collected for DENV testing. We performed M-N-PCR using primers based on NS5 for virus detection and identification. The fragments were purified from PCR mixtures and sequenced. The positive dengue cases were geo-coded. To type the sequenced samples, 52 reference sequences were aligned. The dataset generated was used for iterative phylogenetic reconstruction with the maximum likelihood criterion. The best demographic model, the rate of growth, rate of evolutionary change, and Time to Most Recent Common Ancestor (TMRCA) were estimated. The basic reproductive rate during the epidemics was estimated. We obtained sequences from 82 patients among 174 blood samples. We were able to geo-code 46 sequences. The alignment generated a 399-nucleotide-long dataset with 134 taxa. The phylogenetic analysis indicated that all samples were of DENV-3 and related to strains circulating on the isle of Martinique in 2000–2001. Sixty DENV-3 from São José do Rio Preto formed a monophyletic group (lineage 1), closely related to the remaining 22 isolates (lineage 2). We assumed that these lineages appeared before 2006 in different occasions. By transforming the inferred exponential growth rates into the basic reproductive rate, we obtained values for lineage 1 of R0?=?1.53 and values for lineage 2 of R0?=?1.13. Under the exponential model, TMRCA of lineage 1 dated 1 year and lineage 2 dated 3.4 years before the last sampling. The possibility of inferring the spatio-temporal dynamics from genetic data has been generally little explored, and it may shed light on DENV circulation. The use of both geographic and temporally structured phylogenetic data provided a detailed view on the spread of at least two dengue viral strains in a populated urban area.
Mondini, Adriano; de Moraes Bronzoni, Roberta Vieira; Nunes, Silvia Helena Pereira; Chiaravalloti Neto, Francisco; Massad, Eduardo; Alonso, Wladimir J.; Lazzaro, Eduardo S. M.; Ferraz, Amena Alcantara; de Andrade Zanotto, Paolo Marinho; Nogueira, Mauricio Lacerda
Reported incidence of dengue has increased worldwide in recent decades, but little is known about its incidence in Africa. During 1960–2010, a total of 22 countries in Africa reported sporadic cases or outbreaks of dengue; 12 other countries in Africa reported dengue only in travelers. The presence of disease and high prevalence of antibody to dengue virus in limited serologic surveys suggest endemic dengue virus infection in all or many parts of Africa. Dengue is likely underrecognized and underreported in Africa because of low awareness by health care providers, other prevalent febrile illnesses, and lack of diagnostic testing and systematic surveillance. Other hypotheses to explain low reported numbers of cases include cross-protection from other endemic flavivirus infections, genetic host factors protecting against infection or disease, and low vector competence and transmission efficiency. Population-based studies of febrile illness are needed to determine the epidemiology and true incidence of dengue in Africa.
Kuritsky, Joel N.; Letson, G. William; Margolis, Harold S.
Reported incidence of dengue has increased worldwide in recent decades, but little is known about its incidence in Africa. During 1960-2010, a total of 22 countries in Africa reported sporadic cases or outbreaks of dengue; 12 other countries in Africa reported dengue only in travelers. The presence of disease and high prevalence of antibody to dengue virus in limited serologic surveys suggest endemic dengue virus infection in all or many parts of Africa. Dengue is likely underrecognized and underreported in Africa because of low awareness by health care providers, other prevalent febrile illnesses, and lack of diagnostic testing and systematic surveillance. Other hypotheses to explain low reported numbers of cases include cross-protection from other endemic flavivirus infections, genetic host factors protecting against infection or disease, and low vector competence and transmission efficiency. Population-based studies of febrile illness are needed to determine the epidemiology and true incidence of dengue in Africa. PMID:21801609
Amarasinghe, Ananda; Kuritsk, Joel N; Letson, G William; Margolis, Harold S
... responsibility to understand the causes of foodborne illness and use effective hygienic practices to prevent the transmission of bacteria and viruses ... More results from www.fda.gov/food/guidanceregulation/retailfoodprotection
Background Dengue infection is endemic in many regions throughout the world. While insecticide fogging targeting the vector mosquito Aedes aegypti is a major control measure against dengue epidemics, the impact of this method remains controversial. A previous mathematical simulation study indicated that insecticide fogging minimized cases when conducted soon after peak disease prevalence, although the impact was minimal, possibly because seasonality and population immunity were not considered. Periodic outbreak patterns are also highly influenced by seasonal climatic conditions. Thus, these factors are important considerations when assessing the effect of vector control against dengue. We used mathematical simulations to identify the appropriate timing of insecticide fogging, considering seasonal change of vector populations, and to evaluate its impact on reducing dengue cases with various levels of transmission intensity. Methodology/Principal Findings We created the Susceptible-Exposed-Infectious-Recovered (SEIR) model of dengue virus transmission. Mosquito lifespan was assumed to change seasonally and the optimal timing of insecticide fogging to minimize dengue incidence under various lengths of the wet season was investigated. We also assessed whether insecticide fogging was equally effective at higher and lower endemic levels by running simulations over a 500-year period with various transmission intensities to produce an endemic state. In contrast to the previous study, the optimal application of insecticide fogging was between the onset of the wet season and the prevalence peak. Although it has less impact in areas that have higher endemicity and longer wet seasons, insecticide fogging can prevent a considerable number of dengue cases if applied at the optimal time. Conclusions/Significance The optimal timing of insecticide fogging and its impact on reducing dengue cases were greatly influenced by seasonality and the level of transmission intensity. We suggest that these factors should be considered when planning a control strategy against dengue vectors.
Oki, Mika; Sunahara, Toshihiko; Hashizume, Masahiro; Yamamoto, Taro
Dengue haemorrhagic fever (DHF) is a complicated disease associated with viral and immune pathogenesis. There is still no effective vaccine to prevent the progression of DHF because of its undefined pathogenic mechanisms. The generation of autoimmunity in dengue virus (DEN) infection has been implicated in dengue pathogenesis. Based on our previous studies showing antibodies (Abs) against DEN nonstructural protein 1
Chiou-Feng Lin; Huan-Yao Lei; Ching-Chuan Liu; Hsiao-Sheng Liu; Trai-Ming Yeh; Shun-Hua Chen; Yee-Shin Lin
Background Dengue is a common illness in the tropics. Equally common are neurological complications that stem from dengue infection. However, to date, parkinsonism following dengue has not been reported in medical literature. Case presentation A previously well 18-year old man developed parkinsonism, in addition to other neurological symptoms following serologically confirmed dengue fever. Alternative etiologies were excluded by way of imaging and blood investigations. Conclusions The authors detail the first reported case of parkinsonism complicating dengue fever. Keeping rare presentations of common illnesses in mind, it behoves clinicians to consider parkinsonism as a complication following dengue infection. This would prevent injudicious treatment with L-dopa and dopamine agonists. Immunosuppression with steroids has been shown to be helpful in certain cases.
Dengue viruses are major contributors to illness and death globally. Here we analyze the extrinsic and intrinsic incubation periods (EIP and IIP), in the mosquito and human, respectively. We identified 146 EIP observations from 8 studies and 204 IIP observations from 35 studies. These data were fitted with censored Bayesian time-to-event models. The best-fitting temperature-dependent EIP model estimated that 95% of EIPs are between 5 and 33 days at 25°C, and 2 and 15 days at 30°C, with means of 15 and 6.5 days, respectively. The mean IIP estimate was 5.9 days, with 95% expected between days 3 and 10. Differences between serotypes were not identified for either incubation period. These incubation period models should be useful in clinical diagnosis, outbreak investigation, prevention and control efforts, and mathematical modeling of dengue virus transmission. PMID:23226436
Chan, Miranda; Johansson, Michael A
Dengue is a vector-borne disease that is estimated to affect millions of individuals each year in tropical and subtropical areas, and it is reemerging in areas that have been disease-free for relatively long periods of time. In this issue of the journal, Peng et al. report on a Dengue outbreak in a city in southern China that had been disease-free for more than two decades. The infection, which was due to serotype 1, was introduced by a traveler from South-east Asia and transmitted by Aedes albopictus, the Asian tiger mosquito. Compared to Aedes aegypti, which is the most important vector of Dengue, Ae albopictus is a less competent vector of arboviruses, and the epidemics it causes are milder. However, Ae albopictus is becoming an increasingly important vector because of its rapidly changing global distribution. In particular, the worldwide trade in second hand tires, which often contain water and are an ideal place for eggs and larvae, has been a key factor in the large-scale conquest of Ae albopictus, which easily adapts to new environments, even in a temperate climate. This expansion is creating new opportunities for viruses to circulate in new areas, becoming a common cause of epidemics in Ae aegypti-free countries, from Hawaii to Mauritius. The outbreak in China, like similar events, was mild and short-lived. Because epidemics due to Ae albopictus are milder, the replacement of Ae aegypti with the tiger mosquito could even result in public-health benefits. However, there is no solid evidence of this, and the milder course of the outbreak could be in part explained by the relatively short duration of the hot season in some affected areas. Since it is almost impossible to prevent Ae albopictus from being introduced in a country, mosquito-control measures at local level remain the most effective means of controlling arbovirus outbreaks. PMID:22272602
Background Dengue infection spread in naive populations occurs in an explosive and widespread fashion primarily due to the absence of population herd immunity, the population dynamics and dispersal of Ae. aegypti, and the movement of individuals within the urban space. Knowledge on the relative contribution of such factors to the spatial dimension of dengue virus spread has been limited. In the present study we analyzed the spatio-temporal pattern of a large dengue virus-2 (DENV-2) outbreak that affected the Australian city of Cairns (north Queensland) in 2003, quantified the relationship between dengue transmission and distance to the epidemic's index case (IC), evaluated the effects of indoor residual spraying (IRS) on the odds of dengue infection, and generated recommendations for city-wide dengue surveillance and control. Methods and Findings We retrospectively analyzed data from 383 DENV-2 confirmed cases and 1,163 IRS applications performed during the 25-week epidemic period. Spatial (local k-function, angular wavelets) and space-time (Knox test) analyses quantified the intensity and directionality of clustering of dengue cases, whereas a semi-parametric Bayesian space-time regression assessed the impact of IRS and spatial autocorrelation in the odds of weekly dengue infection. About 63% of the cases clustered up to 800 m around the IC's house. Most cases were distributed in the NW-SE axis as a consequence of the spatial arrangement of blocks within the city and, possibly, the prevailing winds. Space-time analysis showed that DENV-2 infection spread rapidly, generating 18 clusters (comprising 65% of all cases), and that these clusters varied in extent as a function of their distance to the IC's residence. IRS applications had a significant protective effect in the further occurrence of dengue cases, but only when they reached coverage of 60% or more of the neighboring premises of a house. Conclusion By applying sound statistical analysis to a very detailed dataset from one of the largest outbreaks that affected the city of Cairns in recent times, we not only described the spread of dengue virus with high detail but also quantified the spatio-temporal dimension of dengue virus transmission within this complex urban environment. In areas susceptible to non-periodic dengue epidemics, effective disease prevention and control would depend on the prompt response to introduced cases. We foresee that some of the results and recommendations derived from our study may also be applicable to other areas currently affected or potentially subject to dengue epidemics.
Vazquez-Prokopec, Gonzalo M.; Kitron, Uriel; Montgomery, Brian; Horne, Peter; Ritchie, Scott A.
The incidence of dengue has been on the rise since at least the 1960s, bringing greater urgency to the need for a vaccine to prevent the disease. Recent advances suggest that the scientific world is moving closer to an effective dengue vaccine. However, there are concerns that the price of a future vaccine could limit its uptake. High prices, in addition to other challenges, have already weighed negatively in government decisions to include other new vaccines in national immunization programs, e.g., the pneumococcal, rotavirus, and human papillomavirus vaccines. Recent research on the value of vaccination, however, suggests that vaccination confers benefits that are often neglected by traditional economic evaluations. In the case of dengue, commonly overlooked benefits are likely to include reduced spending on outbreak control, averted losses in tourism flows, and avoided productivity losses due to long-term dengue sequelae. Accounting for these and other broader benefits of dengue vaccination could reveal significantly greater economic value and strengthen the case for inclusion of dengue vaccination in national immunization programs. In this article we discuss a framework for the broader value of vaccination and review its application in the context of dengue vaccination for Brazil. PMID:23886895
Bärnighausen, Till; Bloom, David E; Cafiero, Elizabeth T; O'Brien, Jennifer C
In 1990, a Salmonella enteritidis (SE) outbreak occurred in a restaurant chain in Pennsylvania. To determine its cause(s), we conducted a case-control study and a cohort study at one restaurant, and a survey of restaurants. Egg dishes were associated with illness (P = 0.03). Guests from one hotel eating at the restaurant had a diarrhoeal attack rate of 14%, 4.7-fold higher than among those not eating there (P = 0.04). There were no differences in egg handling between affected and unaffected restaurants. Eggs supplied to affected restaurants were medium grade AA eggs from a single farm, and were reportedly refrigerated during distribution. Human and hen SE isolates were phage type 8 and had similar plasmid profiles and antibiograms. We estimate the prevalence of infected eggs during the outbreak to be as high as 1 in 12. Typical restaurant egg-handling practices and refrigeration during distribution appear to be insufficient by themselves to prevent similar outbreaks.
Vugia, D. J.; Mishu, B.; Smith, M.; Tavris, D. R.; Hickman-Brenner, F. W.; Tauxe, R. V.
Purpose. This study was conducted to evaluate the early sonographic findings in dengue hemorrhagic fever. Methods. From July 2002 to September 2002, 86 patients were referred to our center with suspected dengue fever during an outbreak of the disease in Taiwan. All the patients underwent immediate abdom- inal sonography when they arrived at our emergency room. The diagnosis of dengue
Keng-Liang Wu; Chi-Sin Changchien; Chung-Huang Kuo; King-Wah Chiu; Sheng-Nan Lu; Chung-Mou Kuo; Yi-Chun Chiu; Yeh-Pin Chou; Seng-Kee Chuah
... place until the early 1970s. Top of Page Global Dengue Today about 2.5 billion people, or ... Email page link Print page Get email updates Contact Us: Centers for Disease Control and Prevention Dengue ...
Martinique experienced a dengue outbreak with co-circulation of DENV-2 and DENV-4. In an emergency department-based study, we analyzed whether the clinical presentation and outcome of adult patients were related to serotype, immune status, or plasma viral load. Of the 146 adult patients who had confirmed dengue infection, 91 (62.3%) were classified as having classic dengue fever, 11 (7.5%) fulfilled World
Laurent Thomas; Olivier Verlaeten; André Cabié; Stéphane Kaidomar; Victor Moravie; Jenny Martial; Fatiha Najioullah; Yves Plumelle; Christiane Fonteau; Philippe Dussart; Raymond Césaire
Objective: Dengue hemorrhagic fever\\/dengue shock syndrome (DHF\\/DSS) is a growing global health problem. It is not known how age affects the outcome of secondary dengue infections. In an island setting, a large DHF\\/DSS outbreak in Cuba occurred in 1981. Involved were individuals, 3–40 year old, whose only lifetime dengue exposure was to DEN-1 in 1977 and DEN-2 in 1981. In
María G. Guzmán; Gustavo Kouri; Jose Bravo; Luis Valdes; Vazquez Susana; Scott B. Halstead
An outbreak of acute febrile encephalitis affecting pig-farm workers and owners was recognized in peninsular Malaysia as early as September 1998. The outbreak was initially thought to be due to Japanese encephalitis (JE) virus and thus very intensive prevention, control and communication strategies directed at JE virus were undertaken by the Ministry of Health and Ministry of Agriculture of Malaysia. There was an immediate change in the prevention, control and communication strategies with focus and strategies on infected pigs as the source of infections for humans and other animals following the discovery of Nipah virus. Information and understanding the risks of Nipah virus infections and modes of transmission strengthened the directions of prevention, control and communication strategies. A number of epidemiological surveillances and field investigations which were broadly divided into 3 groups covering human health sector, animal health sector and reservoir hosts were carried out as forms of risk assessment to determine and assess the factors and degree of risk of infections by the virus. Data showed that there was significant association between Nipah virus infection and performing activities involving close contact with pigs, such as processing of piglets, administering injection or medication to pigs, assisting in the birth of piglets, assisting in pig breeding, and handling of dead pigs in the affected farms. A complex process of anthropogenic driven deforestation, climatic changes brought on by El Niño-related drought, forest fire and severe haze, and ecological factors of mixed agro-pig farming practices and design of pig-sties led to the spillovers of the virus from its wildlife reservoir into pig population. PMID:21329177
Chua, K B
We analyzed factors associated with severe cases of dengue in children and adolescents hospitalized during the 2007/2008 epidemic in Rio de Janeiro, Brazil. This is a retrospective case-control study that covers 88 cases of severe dengue in patients admitted to four tertiary care children's hospitals. Controls consisted of 22 children with non-severe dengue living in the same neighborhood as the patients with severe dengue. Differences in prevalence of the clinical signs - abdominal pain, breathing difficulty, drowsiness or irritability - emerged on the third day after the onset of symptoms, in the febrile stage. Cases and controls received first medical care at the same clinical stage of disease. However, hospital admission of severe cases occurred later, on average between the third and fourth day after the onset of the disease. Early discharge of patients with fever whose condition could have progressed to severe dengue may have been a consequence of the type of medical assistance provided by primary care units, suggesting deficiencies both in the use of the risk classification protocol and patient triage. PMID:23370027
Gibson, Gerusa; Souza-Santos, Reinaldo; Brasil, Patrícia; Pacheco, Antonio Guilherme; Cruz, Oswaldo G; Honório, Nildimar Alves; Kubelka, Claire; Carvalho, Marilia Sá
Epidemic outbreaks of dengue fever (DF) were first recorded in Venezuela in 1978 and were followed by the emergence of dengue haemorrhagic fever (DHF) outbreaks in 1989. To gain a better understanding of the nature of these epidemics, the complete envelope (E) gene sequence of 34 Venezuelan dengue type 2 (DEN-2) viruses, isolated between 1997 and 2000 was determined. Of
N. Y. Uzcategui; D. Camacho; G. Comach; R. Cuello de Uzcategui; E. C. Holmes; E. A. Gould
... The Signals and Surveillance Team is all about early detection that will limit or prevent illness linked to dietary supplements, cosmetics, and foods ... More results from www.fda.gov/food/recallsoutbreaksemergencies/outbreaks
During the summer of 2012, dengue fever epidemic has emerged in Kolkata and spread throughout West Bengal. During the epidemic period, wide spectrum of atypical presentations of dengue fever has been observed. Here, in this study, the spectrum of dengue fever was analysed in 300 patients who were found to have dengue serology positive (NS1, IgM, IgG). The study was done in the department of medicine, RG Kar Medical College, Kolkata. The patients were classified according to age, gender, duration of symptoms on admission, associated comorbidities and coinfections, complications that developed after admission, the final outcome and duration till death after symptoms developed. The dengue fever cases started to appear from April but it attained its peak during August-September this year. All ages were affected but the brunt was borne maximally by those between 15 and 40 years. Females were more affected than males. It may be concluded from the study that 30% had no complications while 70% cases developed complications, 4% cases had underlying comorbidities and coinfections, 68% developed thrombocytopenia and other haemorrhagic features, 55% serositis, 25% acalculous cholecystitis, 20% myocarditis, 15% pancreatitis, 5% had central nervous system involvement, 0.66% rhabdomyolysis and myositis, 0.33% secondary vasculitis and death occurred in 3% cases. More number of patients were having multiple and atypical complications requiring hospitalisation. Mortality was more common in patients with associated comorbidities and coinfection. Awareness, early treatment with aggressive fluid replacement therapy with close monitoring, supportive management andpatient education showed promising results. PMID:23936956
Majumdar, Ritwika; Jana, Chanchal Kumar; Ghosh, Sandip; Biswas, Uttam
Brazil is the largest country in South America, with 165 million inhabitants largely exposed to dengue outbreaks in the last 16 years. Aedes aegypti was reintroduced in Brazil approximately 25 years ago. Following that, DEN-1, DEN-2 and DEN-3 outbreaks occurred in 1986, 1991 and 2001, respectively. These outbreaks started in Rio de Janeiro and spread to all regions of Brazil.
Luiz Tadeu; Moraes Figueiredo
Herpes gladiatorum (HG) plagues the sport of wrestling, especially in high school wrestlers and summer camps they attend. This study evaluated the usage of valacyclovir to prevent acquisition of primary HG, due to herpes simplex virus type 1 (HSV-1), in high school wrestlers at a 28-day wrestling camp. At the beginning and end of camp, IgM and IgG anti-HSV-1 antibodies were collected. Out of 332 male wrestlers, aged 13-20, who entered camp, 94 elected to participate in blood sampling. Sixty-four were on antiviral medication. Among the 94 wrestlers, 28 (29.8%) had positive IgG anti-HSV-1 titers. Of this group, 66 of 94, were HSV-1 IgG seronegative. At the end of camp, 55 of these original seronegative individuals elected to participate in blood sampling and none had detectable IgM anti-HSV-1 and -2 antibodies. Compared to previous years without antiviral usage, introducing prophylactic valacyclovir reduced clinical HG outbreaks by 87% at this 28-day wrestling camp. Due to the high prevalence of this virus in high school wrestlers, serological testing should be done at the beginning of each season. HSV-1 seropositive individuals should consider being on antiviral medication throughout the season to minimize the risk of transmitting the virus to other wrestlers. PMID:16495626
Anderson, B J
This study analyses education actions and their strategies for preventing and controlling dengue fever, highlighting constraints and difficulties. Conducted through a qualitative approach at the Primary Care Unit and 8 properties in Icaraí, Ceará State, Brazil, its 17 subjects are divided into groups: I (8 PCU users); II (4 Endemic Disease Control Agents); and III (5 healthcare practitioners). The data was collected through semi-structured interviews; participative observation and documentary analyses, using a hermeneutic dialectic analysis method. The findings indicate that health education actions are divergent, while transforming actions are ineffective in terms of impacts on the disease. Difficulties include: weak location-specific actions; educational messages whose contents are not tailored to their contexts; authoritarian and coercive strategies; absence of public policies; gaps between PCU and local population; stress on public health campaigns; practitioners who do not listen to the population and vice-versa; with technical expertise still prevailing over users. The evidence underscores the need for actions strengthening the possibilities of empowering the subjects, helping them become responsible for their own lives and citizenship construction processes. PMID:18813532
Sales, Fátima Maria de Sousa
Study: Although an increasing trend in outbreaks of dengue infection is seen in the northern Indian plains, the importance of dengue infection as a cause of acute undifferentiated febrile illness (AUFI) round the year is not known and the validity of clinical signs and simple laboratory parameters in differentiating dengue from other causes of AUFI has been sparsely reported. Objectives:
R. Kumar; P. Tripathi; S. Tripathi; A. Kanodia; S. Pant; V. Venkatesh
We describe the spread of a dengue virus during an outbreak in Saint Martin island (French West Indies) during winter 2003–2004. Dengue type 3 viruses were isolated from 6 patients exhibiting clinical symptoms. This serotype had not been detected on the island during the preceding 3 years. Genome sequence determinations and analyses showed a common origin with dengue type 3 viruses isolated in Martinique 2 years earlier.
Pastorino, Boris A.M.; Bessaud, Mael; Gravier, Patrick; Tock, Fabienne; Couissinier-Paris, Patricia; Martial, Jenny; Huc-Anais, Patricia; Cesaire, Raymond; Grandadam, Marc; Tolou, Hugues J.
We describe the spread of a dengue virus during an outbreak in Saint Martin island (French West Indies) during winter 2003-2004. Dengue type 3 viruses were isolated from 6 patients exhibiting clinical symptoms. This serotype had not been detected on the island during the preceding 3 years. Genome sequence determinations and analyses showed a common origin with dengue type 3 viruses isolated in Martinique 2 years earlier. PMID:15890134
Peyrefitte, Christophe N; Pastorino, Boris A M; Bessaud, Maël; Gravier, Patrick; Tock, Fabienne; Couissinier-Paris, Patricia; Martial, Jenny; Huc-Anais, Patricia; Césaire, Raymond; Grandadam, Marc; Tolou, Hugues J
In the Lao PDR (Laos), urban dengue is an increasingly recognised public health problem. We describe a dengue-1 virus outbreak in a rural northwestern Lao forest village during the cool season of 2008. The isolated strain was genotypically “endemic” and not “sylvatic,” belonging to the genotype 1, Asia 3 clade. Phylogenetic analyses of 37 other dengue-1 sequences from diverse areas of Laos between 2007 and 2010 showed that the geographic distribution of some strains remained focal overtime while others were dispersed throughout the country. Evidence that dengue viruses have broad circulation in the region, crossing country borders, was also obtained. Whether the outbreak arose from dengue importation from an urban centre into a dengue-naïve community or crossed into the village from a forest cycle is unknown. More epidemiological and entomological investigations are required to understand dengue epidemiology and the importance of rural and forest dengue dynamics in Laos.
Dubot-Peres, Audrey; Vongphrachanh, Phengta; Denny, Justin; Phetsouvanh, Rattanaphone; Linthavong, Singharath; Sengkeopraseuth, Bounthanom; Khasing, Amphai; Xaythideth, Vimattha; Moore, Catrin E.; Vongsouvath, Manivanh; Castonguay-Vanier, Josee; Sibounheuang, Bountoy; Chanthongthip, Anisone; de Lamballerie, Xavier; Newton, Paul N.
Dengue fever outbreaks are reported from India since last 10 years. Since 2005, chikungunya is also causing massive outbreaks in India and other parts of Asia. Both viruses are transmitted by aedes genus and both viruses can re-emerge in many regions due to climatic changes. The clinical presentation of both arthropod borne diseases are similar. Here a concomitant infection of chikungunya and dengue is reported in an 8-year-old child. PMID:23738415
Kumar, K Jagadish; Manjunath, V G; Shailashree, M; Girish, G N
Dengue hemorrhagic fever (DHF) is one of the most important infectious diseases in Thailand for many decades. Knowledge of DHF is vital to its control. Like other tropical countries, Thailand is facing this resurgent disease. The Thai National Dengue Prevention and Control Plan has been recently implemented to prevent and reduce the problems resulting from the spread of DHF. In
In recent foot and mouth disease outbreaks, many healthy animals have been culled to prevent disease transmission. Emergency vaccination is discussed as an alternative to culling of unaffected animals. A spatial and temporal Monte-Carlo simulation model was used to compare preventive culling and emergency vaccination. Different outbreaks are described using additional influence factors such as airborne spread, farm density, type of index-case farm and delay until establishment of the control strategies. The fewest farms were infected establishing a combined strategy including a 1 km preventive culling and 1-10 km emergency vaccination zone around each outbreak farm. Taking the number of culled and vaccinated farms into account, vaccination around the first diagnosed farm combined with the baseline strategy (culling of outbreak farms, protection and surveillance zone, contact tracing) is to be preferred. In the present study, emergency vaccination was an effective control strategy especially in densely populated regions. PMID:21300387
Traulsen, Imke; Rave, Gerhard; Teuffert, Jürgen; Krieter, Joachim
Dengue virus is the most common arboviral infection of humans in the tropical and subtropical regions of the world. This review briefly describes some of the challenges it presents. Dengue is an emerging disease; it is increasing in geographical distribution and severity, despite being significantly underreported. The World Health Organization case definition for the generally more severe manifestation of infection, dengue haemorrhagic fever (DHF), is controversial. The name DHF is something of a misnomer as the disease infrequently results in frank haemorrhage; the hallmark of DHF is actually plasma leakage. The existence of four closely related dengue virus serotypes contributes to difficulties in diagnosis and to original antigenic sin in the serological response to infection. The existence of multiple serotypes can result in more severe disease upon a second infection and complicates vaccine development. Nevertheless, a safe and effective vaccine is the greatest prospect for stemming the tide of dengue. PMID:20696556
Gibbons, Robert V
Background: Dengue fever is one of the most common mosquito-borne viral illnesses in the world. It is usually transmitted to humans through the bite of an infected Aedes aegypti or Aedes albopictus mosquito. Dengue infections are caused by four antigenically distinct but closely related viruses (DEN 1?4). Infection with any one of the viruses is thought to provide lifetime immunity to future infections from the same virus but only short-term cross-immunity to the other types, leading to the possibility of secondary infections. Dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), more severe types of dengue infections, sometimes result when an individual is subsequently infected with a second virus serotype during their lifetime. The most commonly accepted theory for the development of these more severe dengue infections is that of antibody-dependent enhancement, although other factors likely play a role. Infections complicated by DHF/DSS in areas where dengue is endemic are most often seen in the later half of the first year of life, when waning maternal antibodies may enhance the development of a more severe infection, and in young school-age children experiencing secondary infections. Widespread infections are most commonly seen during the rainy season of endemic areas when the breeding habitat of the Aedes mosquito is most favorable. PMID:23817881
Continued Nipah encephalitis outbreaks in Bangladesh highlight the need for preventative and control measures to reduce transmission from bats to humans and human-to-human spread. Qualitative research was conducted at the end of an encephalitis outbreak in Faridpur, Bangladesh in May 2004 and continued through December 2004. Methods included in-depth interviews with caretakers of cases, case survivors, neighbors of cases, and
Lauren S. Blum; Rasheda Khan; Nazmun Nahar; Robert F. Breiman
The current dengue epidemic in Latin America represents a major threat to health. However, surveillance of affected regions lacks timeliness and precision. We investigated real-time electronic sources for monitoring spread of dengue into new regions. This approach could provide timely estimates of changes in distribution of dengue, a critical component of prevention and control efforts.
Keller, Mikaela; Verma, Aman D.; Buckeridge, David L.; Brownstein, John S.
Background & objectives: Dengue is an important arboviral disease. All four dengue virus serotypes are reported to be circulating in India. It is also known that different serotypes, genotypes and clades of genotype determine outbreak severity. Dengue affected children are known to have serious disease outcome. We carried out this study to give reliable diagnosis of dengue infection in children and to detect circulating serotype in central India. Methods: Samples collected from paediatric patients suspected to have dengue fever were subjected to IgM and IgG ELISA to determine dengue virus infection. Samples collected within 0-5 days of onset of illness and positive by IgM ELISA were tested by nested reverse transcription polymerase chain reaction (nRT-PCR). The PCR products were sequenced and analyzed. Results: Of the 89 samples tested, 18 and 7 were positive for dengue IgM and IgG, respectively. Dengue activity was observed in both Jabalpur city and adjoining rural settings. One sample found positive by nRT-PCR was further sequenced to confirm dengue virus 4 as aetiological agent. Interpretation & conclusions: Our findings demonstrated dengue virus infection in children and adolescent in central India. Because of continuous changing epidemiology, it is important to monitor dengue virus activity at both serological and molecular level in this part of the country for better patient care and management.
Barde, P.V.; Godbole, S.; Bharti, P.K.; Chand, Gyan; Agarwal, M.; Singh, Neeru
A large number of autochthonous cases of dengue fever (2237) and chikungunya fever (231) occurred in Europe (Italy, France, Croatia, Madeira) during the period covered by our analysis (2007-2012). In all dengue outbreaks, the circulating strain, identified by means of molecular analysis, was the DENV-1 strain. Dengue and chikungunya are infectious diseases that often result in hospitalizations and are associated with high public health costs. The dengue epidemic on the island of Madeira resulted in 122 hospitalizations. Only one death (from chikungunya) occurred but long-term sequelae were described after the chikungunya outbreak in Emilia-Romagna, Italy. Vector control is key to reducing the impact of these diseases. During the chikungunya outbreak in Italy and the dengue outbreak in Madeira, appropriate measures for the control of mosquitoes (Aedes aegypti and Aedes albopictus) were effectively implemented. The effectiveness of these measures (reducing the number of breeding sites, application of pesticides and insecticides, public health education) was shown in the context of these real-life outbreaks. All the pre-requisites for autochthonous transmission of both dengue virus and chikungunya virus (vectors, viremic returned travellers, climatic conditions) are present in Europe. Constant surveillance is imperative. PMID:23962447
Tomasello, Danilo; Schlagenhauf, Patricia
Over a period of five months (October 1998–February 1999), an outbreak of scabies affected 19 persons associated with a nursing home in Oslo, Norway. Scabies was diagnosed in 13 patients; six long-term patients, five short-term patients also cared for at home, and two home care patients associated with the same institution. Six healthcare workers who had assisted with infected patients
B. M. Andersen; H. Haugen; M. Rasch; A. Heldal Haugen; A. Tageson
Currently, the mechanisms involved in the pathogenesis of DHF\\/DSS remain poorly understood and there is no effective vaccine available to prevent infection with DEN virus. The lack of a reliable small animal model that mimics dengue disease is a major obstacle. In this paper, the development of small animal models such as mice for dengue virus infections is reviewed.
Tao Peng; Junlei Zhang; Jing An
Primary prevention is the most effective measure in dengue prevention and control. The objectives were (i) to determine the level of knowledge and practice of dengue control amongst the study community, and (ii) to explore the factors affecting practice of dengue control in the study area. A cross-sectional study was conducted in a semi-urban Town of Malaysia, using a structured questionnaire covering sociodemography, knowledge related to dengue, knowledge related to Aedes mosquito and preventive measures against the disease. For comparison of survey responses, chi-square test was applied for categorical data. To explore the factors affecting the practice of dengue control, a linear regression model was introduced. Almost all of the respondents (95%) had heard about dengue. Overall, misconceptions of dengue transmission were identified and the practice of dengue control in the study population was insufficient. About half (50.5%) had misconceptions that Aedes can breed in dirty water and the preferred biting time is dusk or sunset (45.6%). Only 44.5% of the households surveyed had covered their water containers properly. Significant associations were found between knowledge scores of dengue and age (P = 0.001), education level (P = 0.001), marital status (P = 0.012), and occupation (P = 0.007). In regression analysis, only the knowledge of dengue was significantly and positively associated with practice on dengue control. A future study with larger samples and more variables to assess the knowledge, attitudes and practices of dengue control is recommended. PMID:21528416
Naing, Cho; Ren, Wong Yih; Man, Chan Yuk; Fern, Koh Pei; Qiqi, Chua; Ning, Choo Ning; Ee, Clarice Wong Syun
The growing burden of dengue in endemic countries and outbreaks in previously unaffected countries stress the need to assess the economic impact of this disease. This paper synthesizes existing studies to calculate the economic burden of dengue illness in the Americas from a societal perspective. Major data sources include national case reporting data from 2000 to 2007, prospective cost of illness studies, and analyses quantifying underreporting in national routine surveillance systems. Dengue illness in the Americas was estimated to cost $2.1 billion per year on average (in 2010 US dollars), with a range of $1–4 billion in sensitivity analyses and substantial year to year variation. The results highlight the substantial economic burden from dengue in the Americas. The burden for dengue exceeds that from other viral illnesses, such as human papillomavirus (HPV) or rotavirus. Because this study does not include some components (e.g., vector control), it may still underestimate total economic consequences of dengue.
Shepard, Donald S.; Coudeville, Laurent; Halasa, Yara A.; Zambrano, Betzana; Dayan, Gustavo H.
Martinique experienced a dengue outbreak with co-circulation of DENV-2 and DENV-4. In an emergency department-based study, we analyzed whether the clinical presentation and outcome of adult patients were related to serotype, immune status, or plasma viral load. Of the 146 adult patients who had confirmed dengue infection, 91 (62.3%) were classified as having classic dengue fever, 11 (7.5%) fulfilled World Health Organization criteria for dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), 21 other patients (14.4%) presented with at least one typical feature of DHF/DSS [i.e., internal hemorrhage, plasma leakage, marked thrombocytopenia (platelet count < or = 50,000 platelets/mm(3)) and/or shock], and 23 further patients (15.8%) had unusual manifestations. Four patients died. Severe illness was more frequent in patients with secondary dengue infection (odds ratio, 7.18; 95% confidence interval, 3.1-16.7; P < 0.001). Multivariate regression analysis showed that gastrointestinal symptoms and other unusual manifestations were independently associated with DENV-2 infection, whereas cough and DHF/DSS features were independently associated with secondary immune response. A high plasma viral load was associated with DENV-2 infection, increased serum liver enzymes, and with DHF/DSS features in patients presenting after the third day of illness. The most severe cases of dengue resulted from the combined effects of DENV-2 and secondary infection. PMID:18541782
Thomas, Laurent; Verlaeten, Olivier; Cabié, André; Kaidomar, Stéphane; Moravie, Victor; Martial, Jenny; Najioullah, Fatiha; Plumelle, Yves; Fonteau, Christiane; Dussart, Philippe; Césaire, Raymond
The invention relates, in general, to chimeric dengue viruses. In particular, the invention relates to chimeric dengue viruses and vaccines comprising same. Further, the invention relates to segments of dengue viral DNA.
C. J. Lai M. Bray
Dengue disease is an increasing global health problem that threatens one-third of the world's population. To control this emerging arbovirus, an efficient preventive vaccine is still needed. Because four serotypes of dengue virus (DV) coexist and antibody-dependent enhanced infection may occur, most strategies developed so far rely on the administration of tetravalent formulations of four live attenuated or chimeric viruses.
Samantha Brandler; Claude Ruffie; Valérie Najburg; Marie-Pascale Frenkiel; Hughes Bedouelle; Philippe Desprès; Frédéric Tangy
At the end of the last century, India has faced resurgence of many infectious diseases, of which dengue is one of the most important in terms of morbidity and mortality. The National Vector Borne Disease Control Program data show that dengue is established in India and is becoming endemic to many areas (dengue cases have increased steadily from ?450 to ?50,000 from 2000 to 2012). Despite extensive efforts being made in developing the effective dengue control measures, the number of dengue cases, their severity, and geographical boundaries are expanding alarmingly and posing dengue as one of the deadly disease. Recently, the increasing burden of dengue in the country has attracted the scientific as well as Indian Government's administrative attention; however, a lot remain to be achieved for managing the disease under threshold level. Like other vector-borne diseases, better management of the dengue needs balanced approach involving various aspects like disease prevention, cure/treatment, and the vector control, simultaneously. We have briefly discussed here the situation of dengue in India and have tried to highlight the worrying facets of dengue control and its implementation in Indian perspective. The review on various aspects of dengue control has revealed an urgent need for permanent surveillance programs, coupled with improvised disease diagnostics, effective anti-dengue treatment measures, and controlling the disease transmission by following an effective implementation of vector control programs. PMID:23455936
Gupta, Bhavna; Reddy, B P Niranjan
Dengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of 'Comprehensive control of Dengue fever under changing climatic conditions'. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named 'DengueTools' to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change.The consortium comprises 12 work packages to address a set of research questions in three areas:Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring.Research area 2: Develop novel strategies to prevent dengue in children.Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change.In this paper, we report on the rationale and specific study objectives of 'DengueTools'. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589 Dengue Tools. PMID:22451836
Wilder-Smith, Annelies; Renhorn, Karl-Erik; Tissera, Hasitha; Abu Bakar, Sazaly; Alphey, Luke; Kittayapong, Pattamaporn; Lindsay, Steve; Logan, James; Hatz, Christoph; Reiter, Paul; Rocklöv, Joacim; Byass, Peter; Louis, Valérie R; Tozan, Yesim; Massad, Eduardo; Tenorio, Antonio; Lagneau, Christophe; L'Ambert, Grégory; Brooks, David; Wegerdt, Johannah; Gubler, Duane
BackgroundDengue dynamics are driven by complex interactions between human-hosts, mosquito-vectors and viruses that are influenced by environmental and climatic factors. The objectives of this study were to analyze and model the relationships between climate, Aedes aegypti vectors and dengue outbreaks in Noumea (New Caledonia), and to provide an early warning system.Methodology\\/Principal FindingsEpidemiological and meteorological data were analyzed from 1971 to
Elodie Descloux; Morgan Mangeas; Christophe Eugène Menkes; Matthieu Lengaigne; Anne Leroy; Temaui Tehei; Laurent Guillaumot; Magali Teurlai; Ann-Claire Gourinat; Justus Benzler; Anne Pfannstiel; Jean-Paul Grangeon; Nicolas Degallier; Xavier De Lamballerie
This study was conducted on seropositive cases of dengue less than 12 years of age admitted in a tertiary-level referral centre during the outbreak of dengue in Chennai, India, between October and December 2001. Fifty-nine cases were admitted during the study period and detailed clinical history, physical examination and laboratory values were recorded on presentation. The cases were followed-up daily
M Narayanan; M A Aravind; P Ambikapathy; R Prema; M P Jeyapaul
Recent outbreaks of dengue fever (DF) along the United States\\/Mexico border, coupled with the high number of reported cases in Mexico suggest that there is the possibility for DF emergence in Houston, Texas1,2. To determine the presence of DF, populations of Aedes aegypti and Aedes albopictus were identified and tested for dengue virus. Maps were created to identify \\
J. Marie Bloemer
In dengue virus infections the asymptomatic cases are much more frequent than the symptomatic ones, but their true role in the introduction and subsequent spread of dengue viruses in non-endemic regions remains to de clarified. We analyzed data from English and French literatures to assess if viremia in asymptomatic dengue infections might be sufficient to represent a true risk. During outbreaks of dengue a large number of individuals are infected and since viremia levels in symptomatic patients are known to vary by many orders of magnitude, it is reasonable to augur that a proportion of asymptomatic cases might reach levels of viremia sufficient to infect competent mosquitoes. In addition, a number of new ways of contamination in man by dengue viruses were recently described such as blood transfusion, bone marrow transplantation, and nosocomial infections that may be worth considering.
Links to the Ongoing Investigations of the Coordinated Outbreak Response and Evaluation (CORE) Network sorted by year. More results from www.fda.gov/food/recalls,%20outbreaks%20&%20emergencies/outbreaks
Background: Nosocomial outbreaks of Salmonella infections in Australia are an infrequent but significant source of morbidity and mortality. Such an outbreak results in direct, measurable expenses for acute care management, as well as numerous indirect (and less quantifiable) costs to those affected, the hospital, and the wider community. This article describes the significant direct costs incurred as a result of
N. M. Spearing; A. Jensen; B. J. McCall; A. S. Neill; J. G. McCormack
Background An estimated 2.4 billion people live in areas at risk of dengue transmission, therefore the factors determining the establishment of endemic dengue in areas where transmission suitability is marginal is of considerable importance. Hanoi, Vietnam is such an area, and following a large dengue outbreak in 2009, we set out to determine if dengue is emerging in Hanoi. Methods and Principal Findings We undertook a temporal and spatial analysis of 25,983 dengue cases notified in Hanoi between 1998 and 2009. Age standardized incidence rates, standardized age of infection, and Standardized Morbidity Ratios (SMR) were calculated. A quasi-Poisson regression model was used to determine if dengue incidence was increasing over time. Wavelet analysis was used to explore the periodicity of dengue transmission and the association with climate variables. After excluding the two major outbreak years of 1998 and 2009 and correcting for changes in population age structure, we identified a significant annual increase in the incidence of dengue cases over the period 1999–2008 (incidence rate ratio ?=?1.38, 95% confidence interval ?=?1.20–1.58, p value ?=?0.002). The age of notified dengue cases in Hanoi is high, with a median age of 23 years (mean 26.3 years). After adjusting for changes in population age structure, there was no statistically significant change in the median or mean age of dengue cases over the period studied. Districts in the central, highly urban, area of Hanoi have the highest incidence of dengue (SMR>3). Conclusions Hanoi is a low dengue transmission setting where dengue incidence has been increasing year on year since 1999. This trend needs to be confirmed with serological surveys, followed by studies to determine the underlying drivers of this emergence. Such studies can provide insights into the biological, demographic, and environmental changes associated with vulnerability to the establishment of endemic dengue.
Cuong, Hoang Quoc; Hien, Nguyen Tran; Duong, Tran Nhu; Phong, Tran Vu; Cam, Nguyen Nhat; Farrar, Jeremy; Nam, Vu Sinh; Thai, Khoa T. D.; Horby, Peter
In 2009, an increased proportion of suspected dengue cases reported to the surveillance system in Puerto Rico were laboratory negative. As a result, enhanced acute febrile illness (AFI) surveillance was initiated in a tertiary care hospital. Patients with fever of unknown origin for 2-7 days duration were tested for Leptospira, enteroviruses, influenza, and dengue virus. Among the 284 enrolled patients, 31 dengue, 136 influenza, and 3 enterovirus cases were confirmed. Nearly half (48%) of the confirmed dengue cases met clinical criteria for influenza. Dengue patients were more likely than influenza patients to have hemorrhage (81% versus 26%), rash (39% versus 9%), and a positive tourniquet test (52% versus 18%). Mean platelet and white blood cell count were lower among dengue patients. Clinical diagnosis can be particularly difficult when outbreaks of other AFI occur during dengue season. A complete blood count and tourniquet test may be useful to differentiate dengue from other AFIs. PMID:23382160
Lorenzi, Olga D; Gregory, Christopher J; Santiago, Luis Manuel; Acosta, Héctor; Galarza, Ivonne E; Hunsperger, Elizabeth; Muñoz, Jorge; Bui, Duy M; Oberste, M Steven; Peñaranda, Silvia; García-Gubern, Carlos; Tomashek, Kay M
Background Because no dengue vaccine or antiviral therapy is commercially available, controlling the primary mosquito vector, Aedes aegypti, is currently the only means to prevent dengue outbreaks. Traditional models of Ae. aegypti assume that population dynamics are regulated by density-dependent larval competition for food and little affected by oviposition behavior. Due to direct impacts on offspring survival and development, however, mosquito choice in oviposition site can have important consequences for population regulation that should be taken into account when designing vector control programs. Methodology/Principal Findings We examined oviposition patterns by Ae. aegypti among 591 naturally occurring containers and a set of experimental containers in Iquitos, Peru. Using larval starvation bioassays as an indirect measure of container food content, we assessed whether females select containers with the most food for their offspring. Our data indicate that choice of egg-laying site is influenced by conspecific larvae and pupae, container fill method, container size, lid, and sun exposure. Although larval food positively influenced oviposition, our results did not support the hypothesis that females act primarily to maximize food for larvae. Females were most strongly attracted to sites containing immature conspecifics, even when potential competitors for their progeny were present in abundance. Conclusion/Significance Due to strong conspecific attraction, egg-laying behavior may contribute more to regulating Ae. aegypti populations than previously thought. If highly infested containers are targeted for removal or larvicide application, females that would have preferentially oviposited in those sites may instead distribute their eggs among other suitable, previously unoccupied containers. Strategies that kill mosquitoes late in their development (i.e., insect growth regulators that kill pupae rather than larvae) will enhance vector control by creating “egg sinks,” treated sites that exploit conspecific attraction of ovipositing females, but reduce emergence of adult mosquitoes via density-dependent larval competition and late acting insecticide.
Wong, Jacklyn; Stoddard, Steven T.; Astete, Helvio; Morrison, Amy C.; Scott, Thomas W.
Since no protective vaccine or specific treatments are available for dengue fever\\/dengue hemorrhagic fever (DHF), accurate diagnosis is critical for the early initiation of specific preventive health measures to curtail epidemic spread and reduce economic losses. Commonly used diagnosis methods for confirming dengue infection involve virus isolation, detection of virus antigen or RNA in plasma or serum or tissues, and
Chuan-Liang Kao; Chwan-Chuen King; Day-Yu Chao; Hui-Lin Wu; Gwong-Jen J. Chang
Noroviruses are the most common cause of epidemic gastroenteritis, responsible for at least 50% of all gastroenteritis outbreaks worldwide, and a major cause of foodborne illness. In the United States, approximately 21 million illnesses attributable to no...
A. J. Hall B. Lopman C. Yen G. W. Park J. Vinje N. Gregoricus U. Parashar
Bangladesh is experiencing resurgence of' dengue endemic since 2000. In an attempt to see the pattern of' dengue infection we analyzed retrospectively results of 225 blood samples from patients having fever and clinically suspected to have been suffering from dengue fever who were tested for dengue IgM and IgG in Health Care Development Project (HCDP), Dhaka, an enterprise of Diabetic Association of Bangladesh (DAB) one of the largest private health care facility provider in Bangladesh. Out of 225 samples tested, a total of 156(69.33%) cases were serologically positive for dengue and 69(30.67%) were negative. Of the positive cases, 70(44.87%) were positive for Dengue IgM and 86(55.13%) were positive for Dengue IgG. which showed statistical difference between male and female (p<0.05). Both IgM and IgG, were positive in 23(14, 74%) cases. The mean age +/-SD of affected is 36.86+/-17.60 years and the maximum number of positive cases 114(73.08%) diagnosed were in the months between July-December. It is evident from the present study that dengue is endemic in Dhaka city particularly during monsoon and rainy season. Secondary dengue is more common than primary dengue and both preventive and curative measures are needed to combat this menace. PMID:17703160
Rahman, M T; Tahmin, H A; Mannan, T; Sultana, R
Dengue is an emerging disease in Nepal and was first observed as an outbreak in nine lowland districts in 2006. In 2010, however, a large epidemic of dengue occurred with 4,529 suspected and 917 serologically-confirmed cases and five deaths reported in government hospitals in Nepal. The collection of demographic information was performed along with an entomological survey and clinical evaluation of the patients. A total of 280 serum samples were collected from suspected dengue patients. These samples were subjected to routine laboratory investigations and IgM-capture ELISA for dengue serological identification, and 160 acute serum samples were used for virus isolation, RT-PCR, sequencing and phylogenetic analysis. The results showed that affected patients were predominately adults, and that 10% of the cases were classified as dengue haemorrhagic fever/ dengue shock syndrome. The genetic characterization of dengue viruses isolated from patients in four major outbreak areas of Nepal suggests that the DENV-1 strain was responsible for the 2010 epidemic. Entomological studies identified Aedes aegypti in all epidemic areas. All viruses belonged to a monophyletic single clade which is phylogenetically close to Indian viruses. The dengue epidemic started in the lowlands and expanded to the highland areas. To our knowledge, this is the first dengue isolation and genetic characterization reported from Nepal.
Pandey, Basu D.; Nabeshima, Takeshi; Pandey, Kishor; Rajendra, Saroj P.; Shah, Yogendra; Adhikari, Bal R.; Gupta, Govinda; Gautam, Ishan; Tun, Mya M. N.; Uchida, Reo; Shrestha, Mahendra; Kurane, Ichiro; Morita, Kouichi
Dengue is an emerging disease in Nepal and was first observed as an outbreak in nine lowland districts in 2006. In 2010, however, a large epidemic of dengue occurred with 4,529 suspected and 917 serologically-confirmed cases and five deaths reported in government hospitals in Nepal. The collection of demographic information was performed along with an entomological survey and clinical evaluation of the patients. A total of 280 serum samples were collected from suspected dengue patients. These samples were subjected to routine laboratory investigations and IgM-capture ELISA for dengue serological identification, and 160 acute serum samples were used for virus isolation, RT-PCR, sequencing and phylogenetic analysis. The results showed that affected patients were predominately adults, and that 10% of the cases were classified as dengue haemorrhagic fever/ dengue shock syndrome. The genetic characterization of dengue viruses isolated from patients in four major outbreak areas of Nepal suggests that the DENV-1 strain was responsible for the 2010 epidemic. Entomological studies identified Aedes aegypti in all epidemic areas. All viruses belonged to a monophyletic single clade which is phylogenetically close to Indian viruses. The dengue epidemic started in the lowlands and expanded to the highland areas. To our knowledge, this is the first dengue isolation and genetic characterization reported from Nepal. PMID:24155651
Pandey, Basu D; Nabeshima, Takeshi; Pandey, Kishor; Rajendra, Saroj P; Shah, Yogendra; Adhikari, Bal R; Gupta, Govinda; Gautam, Ishan; Tun, Mya M N; Uchida, Reo; Shrestha, Mahendra; Kurane, Ichiro; Morita, Kouichi
Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. In more severe or complicated dengue, patients present with a severe febrile illness characterized by abnormalities of hemostasis and increased vascular permeability, which in some instances results in a hypovolemic shock. Four distinct serotypes of the dengue virus (dengue-1, dengue-2, dengue-3, and dengue-4) exist, with numerous virus strains found worldwide. Molecular cloning methods have led to a greater understanding of the structure of the RNA genome and definition of virus-specific structural and nonstructural proteins. Progress towards producing safe, effective dengue virus vaccines, a goal for over 45 years, has been made. Images
Henchal, E A; Putnak, J R
Text VersionDengue Transfusion Risk Model. Lyle R. Petersen, MD, MPH. ... D s = Duration of viremia before symptoms develop. Dengue Risk Model Variables. ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials
Background During the last decades, dengue viruses have spread throughout the Americas region, with an increase in the number of severe\\u000a forms of dengue. The surveillance system in Guadeloupe (French West Indies) is currently operational for the detection of\\u000a early outbreaks of dengue. The goal of the study was to improve this surveillance system by assessing a modelling tool to\\u000a predict
Myriam Gharbi; Philippe Quenel; Joël Gustave; Sylvie Cassadou; Guy La Ruche; Laurent Girdary; Laurence Marrama
Aedes aegypti, eradicated from Argentina in 1963, has now reinfested the country as far south as Buenos Aires. In 1997, four persons with travel histories to Brazil, Ecuador, or Venezuela had confirmed dengue, and surveillance for indigenous transmission allowed the detection of 19 dengue cases in Salta Province. These cases of dengue are the first in Argentina since 1916 and represent a new southern extension of dengue virus.
Aviles, G.; Rangeon, G.; Vorndam, V.; Briones, A.; Baroni, P.; Enria, D.; Sabattini, M. S.
The extent of cumulative disease burden caused by dengue virus has attained an unprecedented level in recent times with sharp increase in the size of human population at risk. Dengue disease presents highly complex medical, economic and ecologic problems. The surge in publications on the development of dengue vaccines, taking advantage of new generation of biotechnology techniques indicates the profound
U. C. Chaturvedi; Richa Shrivastava; Rachna Nagar
We assessed in a case-control study the test-validity of Aedes larval indices for the 2000 Havana outbreak. "Cases" were blocks where a dengue fever patient lived during the outbreak. "Controls" were randomly sampled blocks. Before, during, and after the epidemic, we calculated Breteau index (BI) and house index at the area, neighborhood, and block level. We constructed receiver operating characteristic (ROC) curves to determine their performance as predictors of dengue transmission. We observed a pronounced effect of the level of measurement. The BImax (maximum block BI in a radius of 100 m) at 2-month intervals had an area under the ROC curve of 71%. At a cutoff of 4.0, it significantly (odds ratio 6.00, p<0.05) predicted transmission with 78% sensitivity and 63% specificity. Analysis of BI at the local level, with human-defined boundaries, could be introduced in control programs to identify neighborhoods at high risk for dengue transmission.
Sanchez, Lizet; Vanlerberghe, Veerle; Alfonso, Lazara; Marquetti, Maria del Carmen; Guzman, Maria Guadalupe; Bisset, Juan; van der Stuyft, Patrick
Outbreaks of Dengue impose a heavy economic burden on developing countries in terms of vector control and human morbidity. Effective vaccines against all four serotypes of Dengue are in development, but population replacement with transgenic vectors unable to transmit the virus might ultimately prove to be an effective approach to disease suppression, or even eradication. A key element of the
Pruksa Nawtaisong; James Keith; Tresa Fraser; Velmurugan Balaraman; Andrey Kolokoltsov; Robert A Davey; Stephen Higgs; Ahmed Mohammed; Yupha Rongsriyam; Narumon Komalamisra; Malcolm J Fraser Jr
BackgroundDemographic features of dengue fever have changed tremendously in Pakistan over the past two decades. Small scale studies from all over the country have reported different aspects of individual outbreaks during this time. However, there is scarcity of data looking at the overall trend of dengue virus infection in the country. In this study, we examined annual trends, seasonality, and
Erum Khan; Mehreen Kisat; Nabil Khan; Amna Nasir; Salma Ayub; Rumina Hasan; Aric Gregson
Dengue fever is a multistrain mosquito-borne subtropical disease that exhibits complex oscillatory outbreaks. Epidemiological data from Thailand displays traveling waves of infection originating in Bangkok, the largest population center (Cummings et al., Nature 427: 344, 2004). We present a multistrain metapopulation model in which traveling wave like behavior results from migration coupling between heterogeneous regions. The region with the highest
Simone Bianco; Andrea Faatz; Derek Cummings; Leah Shaw
Our objective was to determine the association between temperature, humidity, rainfall and dengue activity in Singapore, after taking into account lag periods as well as long-term climate variability such as the El Niño Southern Oscillation Index (SOI). We used a Poisson model which allowed for autocorrelation and overdispersion in the data. We found weekly mean temperature and mean relative humidity as well as SOI to be significantly and independently associated with dengue notifications. There was an interaction effect by periods of dengue outbreaks, but periods where El Niño was present did not moderate the relationship between humidity and temperature with dengue notifications. Our results help to understand the temporal trends of dengue in Singapore, and further reinforce the findings that meteorological factors are important in the epidemiology of dengue. PMID:21906411
Earnest, A; Tan, S B; Wilder-Smith, A
Introduction: Dengue is an acute viral infection which presents as uneventful pyrexia to a fatal complication. This infection is increasingly being recognized as the world’s major emerging tropical disease and an important public health problem. This article highlights the clinical manifestations of Dengue virus infection and the various molecular tests that were used for its laboratory diagnosis. Methods: Serum samples from 713 suspected cases of Dengue were collected between August and December 2007. The clinical profiles of 123 hospitalized patients were analyzed. Serology, RT- PCR, virus isolation and sequencing were done. Results: The most common clinical symptoms were fever, thrombocytopenia, rash and elevated liver enzymes. The demonstration of the Dengue RNA in 5.16% samples, the detection of Dengue specific IgM antibodies in 18% samples and the isolation of the DENV-4 and the DENV-3 viruses from the clinical samples confirmed this Dengue outbreak. A co -infection with Chikungunya was observed in 2.06% of the cases. The phylogenetic analysis revealed that the Indian Dengue-4 isolates from this outbreak belonged to the genotype I. This study clearly indicated the sudden dominance of DENV-4 in an Indian Dengue outbreak. Conclusion: The surveillance of the Dengue viruses needs to be closely monitored for the emergence of newer serotype(s) in hitherto unknown areas.
Neeraja, Mamidi; Lakshmi, Vemu; Dash, P.K.; Parida, M.M.; Rao, P.V.L.
Emergence of the Severe Syndrome and Mortality Associated with Dengue and Dengue-Like Illness: Historical Records (1890 to 1950) and Their Compatibility with Current Hypotheses on the Shift of Disease Manifestation
Summary: Outbreaks of the severe dengue syndrome, dengue hemorrhagic fever (DHF), emerged beginning in the 1950s, marking a dramatic change in the dengue syndrome. While intense investigations in multiple directions have been conducted for many years to elucidate the intrinsic mechanisms conducive to the development of DHF, no consensus has yet emerged. Meanwhile, relatively little attention has been paid to the occurrence of severe dengue and death prior to the 1950s. This comprehensive review was designed to evaluate outbreak records in the early dengue history to better understand the epidemiologic background and other factors that existed before the emergence of DHF outbreaks. By applying a set of stringent criteria to remove unreliable data as much as possible and by interpreting the results conservatively, a short list of etiologically more reliable outbreaks with high mortality was obtained. The results show that severe dengue syndrome, clinically very much compatible with DHF, occurred far more frequently in multiple locations than it had been assumed before; that the magnitudes of mortality in several outbreaks were not negligible; and that the epidemiologic background features shared among these outbreaks in the early period were, with the exceptions of more limited demographic changes, generally similar to the post-1950 conditions.
To investigate the changes in community responsiveness during the pre-community-outbreak phase of the H1N1 epidemic in Hong Kong, a pooled sample of 999 adults was interviewed in three surveys (S1, S2, S3) from 7 May to 6 June 2009. Over time, fewer people felt confident in staying free from H1N1 infection in the following year (S1, 63·3%; S3, 46%; P<0·001). The level of distress due to H1N1 remained modest throughout the study period. People's confidence in the government's ability to control a large-scale H1N1 outbreak declined slightly at the third survey (S1, 80·5%; S3, 73·8%; P=0·025). Across the three surveys, respondents remained vigilant with frequent adoption of preventive measures (e.g. wearing face masks in public areas when suffering from influenza-like symptoms and frequent hand-washing). The public was generally supportive of the Hong Kong government although misconceptions regarding the disease were common. Provision of evidence-based public-health education is still warranted as the disease outbreak unfolds. PMID:20800008
Lau, J T F; Griffiths, S; Au, D W H; Choi, K C
Background We describe an outbreak of Bullous Impetigo (BI), caused by a (methicillin susceptible, fusidic acid resistant) Staphylococcus aureus (SA) strain, spa-type t408, at the neonatal and gynaecology ward of the Jeroen Bosch hospital in the Netherlands, from March-November 2011. Methods We performed an outbreak investigation with revision of the hygienic protocols, MSSA colonization surveillance and environmental sampling for MSSA including detailed typing of SA isolates. Spa typing was performed to discriminate between the SA isolates. In addition, Raman-typing was performed on all t408 isolates. Results Nineteen cases of BI were confirmed by SA positive cultures. A cluster of nine neonates and three health care workers (HCW) with SA t408 was detected. These strains were MecA-, PVL-, Exfoliative Toxin (ET)A-, ETB+, ETAD-, fusidic acid-resistant and methicillin susceptible. Eight out of nine neonates and two out of three HCW t408 strains yielded a similar Raman type. Positive t408 HCW were treated and infection control procedures were reinforced. These measures stopped the outbreak. Conclusions We conclude that treatment of patients and HCW carrying a predominant SA t408, and re-implementing and emphasising hygienic measures were effective to control the outbreak of SA t408 among neonates.
|A flu outbreak at Madison Junior High School in Ohio prompted school officials to close the building for two days. At Webber Junior High School in Fort Collins, Colorado, where absenteeism recently hit 20 percent for two bad weeks, educators were forced to slow the pace of schoolwork so sick students did not fall behind. This article reports on…
Jacobson, Linda; Bowman, Darcia Harris
Background Although most symptomatic dengue infections follow an uncomplicated course, complications and unusual manifestations are increasingly being reported due to rising disease burden. Expanded dengue syndrome is a new entity added into World Health Organization (WHO) classification system to incorporate this wide spectrum of unusual manifestations. We report a case of expanded dengue syndrome with subacute thyroiditis and intracerebral hemorrhage. This is the first case report of thyroiditis in dengue infection. Case presentation A 20?years old man presented with fever, myalgias, arthralgias, retro-orbital pain, vomiting and gum bleeding during a large dengue outbreak in Lahore, Pakistan. On 7th day of illness patient became afebrile, but he developed severe headaches, unconsciousness followed by altered behavior. On 9th day of illness patient developed painful neck swelling accompanied by fever, tremors, palpitations, hoarseness of voice and odynophagia. Examination revealed acutely swollen, tender thyroid gland along with features of hyperthyroidism. Laboratory evaluation revealed stable hematocrit, thrombocytopenia and leukopenia. Patient had seroconverted for anti-dengue IgM antibodies on the 10th day of illness. A non-contrast Computed Tomogram (CT) of the brain showed right frontal lobe hematoma. Thyroid profile showed increased free T3 and T4 and low TSH. Technetium thyroid scan showed reduced tracer uptake. He was diagnosed as having subacute thyroiditis and treated with oral prednisolone and propranolol. Follow up CT brain showed resolving hematoma. Patient’s recovery was uneventful. Conclusion Subacute thyroiditis may develop during the course of dengue fever and should be included as a manifestation of expanded dengue syndrome. It should be suspected in patients with dengue fever who develop painful thyroid swelling and clinical features of hyperthyroidism.
Emergency control of disease vectors requires high efficacy, rapid reaction and safe use of biocides in order interrupt transmission\\u000a cycles without harming humans, non-target animals and the environment. In countries with complex emergencies, air-borne large-scale\\u000a vector control is often limited, or impossible, due to questionable security as well as military, safety, equipment, or logistical\\u000a constraints. While facing a potential outbreak
M. K. Faulde; J. J. Scharninghausen; M. Tisch
Background Dengue virus infection has recently taken endemic proportion in India implicating all the four known dengue serotypes. There was a major dengue outbreak in northern India including Delhi in October- December, 2003 and again in 2004. We have carried out a detailed investigation of the 2004 outbreak by Serosurveillance, RT-PCR, nested PCR, virus isolation and genotyping. We also report the molecular epidemiological investigation of these outbreaks. Results The serological investigation of 162 suspected serum samples using an in-house dengue dipstick ELISA revealed 11%-IgM, 51%-IgG and 38%-both IgM and IgG antibody positivity. The RT-PCR analysis revealed presence of dengue RNA in 17 samples. Further subtyping and genotyping by nested PCR and nucleotide sequencing of C-prM gene junction revealed the association of subtype III of dengue virus type 3 in the outbreak. Conclusion The sudden shifting and dominance of the dengue virus serotype-3 (subtype III) replacing the earlier circulating serotype-2 (subtype IV) is a point of major concern and may be attributed to increased incidence of DHF and DSS in India.
Dash, Paban Kumar; Parida, Man Mohan; Saxena, Parag; Abhyankar, Ajay; Singh, CP; Tewari, KN; Jana, Asha Mukul; Sekhar, K; Rao, PV Lakshmana
Urban dengue is common in most countries of the Americas, but has been rare in the United States for more than half a century. In 1999 we investigated an outbreak of the disease that affected Nuevo Laredo, Tamaulipas, Mexico, and Laredo, Texas, United States, contiguous cities that straddle the international border. The incidence of recent cases, indicated by immunoglobulin M antibody serosurvey, was higher in Nuevo Laredo, although the vector, Aedes aegypti, was more abundant in Laredo. Environmental factors that affect contact with mosquitoes, such as air-conditioning and human behavior, appear to account for this paradox. We conclude that the low prevalence of dengue in the United States is primarily due to economic, rather than climatic, factors.
Lathrop, Sarah; Bunning, Michel; Biggerstaff, Brad; Singer, Daniel; Tiwari, Tejpratap; Baber, Laura; Amador, Manuel; Thirion, Jaime; Hayes, Jack; Seca, Calixto; Mendez, Jorge; Ramirez, Bernardo; Robinson, Jerome; Rawlings, Julie; Vorndam, Vance; Waterman, Stephen; Gubler, Duane; Clark, Gary; Hayes, Edward
An optimal control problem for a host-vector Dengue transmission model is discussed here. In the model, treatments with mosquito repellent are given to adults and children and those who undergo treatment are classified in treated compartments. With this classification, the model consists of 11 dynamic equations. The basic reproductive ratio that represents the epidemic indicator is obtained from the largest eigenvalue of the next generation matrix. The optimal control problem is designed with four control parameters, namely the treatment rates for children and adult compartments, and the drop-out rates from both compartments. The cost functional accounts for the total number of the infected persons, the cost of the treatment, and the cost related to reducing the drop-out rates. Numerical results for the optimal controls and the related dynamics are shown for the case of epidemic prevention and outbreak reduction strategies. PMID:23274179
Aldila, Dipo; Götz, Thomas; Soewono, Edy
Dengue viruses (DENV) serotypes 1, 2, and 3 have been causing yearly outbreaks in Brazil. In this study, we report the re-introduction of DENV2 in the coast of São Paulo State. Partial envelope viral genes were sequenced from eighteen patients with dengue fever during the 2010 epidemic. Phylogenetic analysis showed this strain belongs to the American\\/Asian genotype and was closely
Camila Malta Romano; Andréia Manso de Matos; Evaldo Stanislau A. Araújo; Lucy Santos Villas-Boas; Wanessa Cardoso da Silva; Olímpia M. N. P. F. Oliveira; Karina I. Carvalho; Ana Carolina Mamana de Souza; Celia L. Rodrigues; José Eduardo Levi; Esper G. Kallas; Claudio Sergio Pannuti; Laurent Rénia
We present our surveillance results on imported dengue cases in Taiwan during 2008–2010. A total of 734 imported dengue patients were identified. The travelers were arriving from 18 countries, including Southeast Asia, the Indian subcontinent, South Pacific islands, and Latin America. Gene sequences from 358 dengue virus (DENV) isolates were used to perform phylogenetic analyses, thus, providing an updated view of the geographic distribution and dynamic transmission of DENV strains circulating in these countries. Our results suggest that the DENV-1 genotype I and DENV-2 Cosmopolitan genotype comprise the predominant DENV strains circulating in Southeast Asian countries. The DENV-3 Genotype III strain was found to be newly emerging in several Southeast Asian countries, however, the Asian genotype 2 and the Asian/American genotype of DENV-2 strains appeared to be less prevalent in Southeast Asia. Furthermore, imported dengue viruses are representative of the overall patterns of serotype/genotype frequencies of dengue outbreaks that occurred in Taiwan.
Huang, Jyh-Hsiung; Su, Chien-Ling; Yang, Cheng-Fen; Liao, Tsai-Ling; Hsu, Tung-Chien; Chang, Shu-Fen; Lin, Chien-Chou; Shu, Pei-Yun
Background The mosquito-borne dengue viruses are a major public health problem throughout the tropical and subtropical regions of the world. Changes in temperature and precipitation have well-defined roles in the transmission cycle and may thus play a role in changing incidence levels. The El Niño Southern Oscillation (ENSO) is a multiyear climate driver of local temperature and precipitation worldwide. Previous studies have reported varying degrees of association between ENSO and dengue incidence. Methods and Findings We analyzed the relationship between ENSO, local weather, and dengue incidence in Puerto Rico, Mexico, and Thailand using wavelet analysis to identify time- and frequency-specific association. In Puerto Rico, ENSO was transiently associated with temperature and dengue incidence on multiyear scales. However, only local precipitation and not temperature was associated with dengue on multiyear scales. In Thailand, ENSO was associated with both temperature and precipitation. Although precipitation was associated with dengue incidence, the association was nonstationary and likely spurious. In Mexico, no association between any of the variables was observed on the multiyear scale. Conclusions The evidence for a relationship between ENSO, climate, and dengue incidence presented here is weak. While multiyear climate variability may play a role in endemic interannual dengue dynamics, we did not find evidence of a strong, consistent relationship in any of the study areas. The role of ENSO may be obscured by local climate heterogeneity, insufficient data, randomly coincident outbreaks, and other, potentially stronger, intrinsic factors regulating transmission dynamics. Please see later in the article for the Editors' Summary
Johansson, Michael A.; Cummings, Derek A. T.; Glass, Gregory E.
The impact of weather variation on dengue transmission in Cairns, Australia, was determined by applying a process-based dengue simulation model (DENSiM) that incorporated local meteorologic, entomologic, and demographic data. Analysis showed that inter-annual weather variation is one of the significant determinants of dengue outbreak receptivity. Cross-correlation analyses showed that DENSiM simulated epidemics of similar relative magnitude and timing to those historically recorded in reported dengue cases in Cairns during 1991-2009, (r = 0.372, P < 0.01). The DENSiM model can now be used to study the potential impacts of future climate change on dengue transmission. Understanding the impact of climate variation on the geographic range, seasonality, and magnitude of dengue transmission will enhance development of adaptation strategies to minimize future disease burden in Australia. PMID:23166197
Bannister-Tyrrell, Melanie; Williams, Craig; Ritchie, Scott A; Rau, Gina; Lindesay, Janette; Mercer, Geoff; Harley, David
The role played by food workers and other individuals in the contamination of food has been identified as an important contributing factor leading to foodborne outbreaks. To prevent direct bare hand contact with food and food surfaces, many jurisdictions have made glove use compulsory for food production and preparation. When properly used, gloves can substantially reduce opportunities for food contamination. However, gloves have limitations and may become a source of contamination if they are punctured or improperly used. Experiments conducted in clinical and dental settings have revealed pinhole leaks in gloves. Although such loss of glove integrity can lead to contamination of foods and surfaces, in the food industry improper use of gloves is more likely than leakage to lead to food contamination and outbreaks. Wearing jewelry (e.g., rings) and artificial nails is discouraged because these items can puncture gloves and allow accumulation of microbial populations under them. Occlusion of the skin during long-term glove use in food operations creates the warm, moist conditions necessary for microbial proliferation and can increase pathogen transfer onto foods through leaks or exposed skin or during glove removal. The most important issue is that glove use can create a false sense of security, resulting in more high-risk behaviors that can lead to cross-contamination when employees are not adequately trained. PMID:20828485
Todd, Ewen C D; Michaels, Barry S; Greig, Judy D; Smith, Debra; Bartleson, Charles A
Background Travelers who acquire dengue infection are often routes for virus transmission to other regions. Nevertheless, the interplay between infected travelers, climate, vectors, and indigenous dengue incidence remains unclear. The role of foreign-origin cases on local dengue epidemics thus has been largely neglected by research. This study investigated the effect of both imported dengue and local meteorological factors on the occurrence of indigenous dengue in Taiwan. Methods and Principal Findings Using logistic and Poisson regression models, we analyzed bi-weekly, laboratory-confirmed dengue cases at their onset dates of illness from 1998 to 2007 to identify correlations between indigenous dengue and imported dengue cases (in the context of local meteorological factors) across different time lags. Our results revealed that the occurrence of indigenous dengue was significantly correlated with temporally-lagged cases of imported dengue (2–14 weeks), higher temperatures (6–14 weeks), and lower relative humidity (6–20 weeks). In addition, imported and indigenous dengue cases had a significant quantitative relationship in the onset of local epidemics. However, this relationship became less significant once indigenous epidemics progressed past the initial stage. Conclusions These findings imply that imported dengue cases are able to initiate indigenous epidemics when appropriate weather conditions are present. Early detection and case management of imported cases through rapid diagnosis may avert large-scale epidemics of dengue/dengue hemorrhagic fever. The deployment of an early-warning surveillance system, with the capacity to integrate meteorological data, will be an invaluable tool for successful prevention and control of dengue, particularly in non-endemic countries.
Shang, Chuin-Shee; Wen, Tzai-Hung; Tsai, Kun-Hsien
Background Dengue is a mosquito-borne viral disease endemic in many countries in the tropics and sub-tropics. The disease affects mainly children, but in recent years it is becoming more of an adult disease. Malaysia experienced a large dengue outbreak in 2006 to 2007, involving mostly adults, with a high number of deaths. Methodology/Principal Findings We undertook a retrospective study to examine dengue death cases in our hospital from June 2006 to October 2007 with a view to determine if there have been changes in the presentation of severe to fatal dengue. Nine of ten fatal cases involved adult females with a median age of 32 years. All had secondary dengue infection. The mean duration of illness prior to hospitalization was 4.7 days and deaths occurred at an average of 2.4 days post-admission. Gastrointestinal pain, vomiting, diarrhea, intravascular leakages and bleeding occurred in the majority of cases. DSS complicated with severe bleeding, multi-organ failure and coagulopathy were the primary causes of deaths. Seven patients presented with thrombocytopenia and hypoalbuminemia, five of which had hemoconcentration and increased ALT and AST indicative of liver damage. Co-morbidities particularly diabetes mellitus was common in our cohort. Prominent unusual presentations included acute renal failure, acute respiratory distress syndrome, myocarditis with pericarditis, and hemorrhages over the brain and heart. Conclusions In our cohort, dengue fatalities are seen primarily in adult females with secondary dengue infection. The majority of the patients presented with common clinical and laboratory warning signs of severe dengue. Underlying co-morbidities may contribute to the rapid clinical deterioration in severe dengue. The uncommon presentations of dengue are likely a reflection of the changing demographics where adults are now more likely to contract dengue in dengue endemic regions.
Sam, Sing-Sin; Omar, Sharifah Faridah Syed; Teoh, Boon-Teong; Abd-Jamil, Juraina; AbuBakar, Sazaly
Dengue is the most important disease caused by an arbovirus (1, 2, 3 and 4 serotypes) worldwide, especially in the tropical and sub-tropical regions. Its clinical manifestations range from asymptomatic infections to a severe disease characterized by hemorrhage and shock. The incidence of dengue virus activity in the Americas has substantially increased from 1980 to 1994. In Brazil, the increase in the incidence of dengue is especially linked to the dissemination of Aedes aegypti. Thus, a rapid and accurate dengue diagnosis is of paramount importance for effective control of dengue outbreaks . Five serological tests have been used for the diagnosis of dengue infection: hemagglutination-inhibition (HI), complement fixation (CF), neutralization test (NT), immunoglobulin M (IgM) capture enzyme linked immunosorbent assay (MAC-ELISA) and indirect immunoglobulin G ELISA. The limitations of these techniques are the high cross-reactivity observed with these tests. Four methods of viral isolation have been routinely used for dengue viruses: intracerebral inoculation of newborn mice, inoculation on mammalian cell cultures, intrathoracic inoculation of adult mosquitoes, and inoculation on mosquito cell cultures. In recent years, several new diagnostic techniques have been developed and have proven very useful in dengue diagnosis, such as: nucleic and acid hybridization, RT-PCR. Currently, dengue diagnosis is based on serology, viral isolation and RNA detection. Enzyme-linked immunosorbent assays (ELISA) are still the most widely used technique for serological diagnosis, but they do not identify the dengue virus serotype responsible for the current infection, so molecular techniques may soon assume a very important role in dengue diagnosis. RT-PCR is definitely the most satisfactory test that can be used on these infections, since it has been shown to be able to detect dengue viruses up to the 10th day after the onset of the symptoms. PMID:15880229
De Paula, Sérgio Oliveira; Fonseca, Benedito Antônio Lopes da
Dengue-1 viruses responsible for the dengue fever outbreak in Easter Island in 2002 were isolated from acute-phase sera of dengue fever patients. In order to analyze the complete genome sequence, we designed primers to amplify contiguous segments across the entire sequence of the viral genome. RT-PCR products obtained were cloned, and complete nucleotide and deduced amino acid sequences were determined. This report constitutes the first complete genetic characterization of a DENV-1 isolate from Chile. Phylogenetic analysis shows that an Easter Island isolate is most closely related to Pacific DENV-1 genotype IV viruses. PMID:18815724
Cáceres, C; Yung, V; Araya, P; Tognarelli, J; Villagra, E; Vera, L; Fernández, J
Numerous outbreaks of shellfish-borne enteric virus illness have been reported worldwide. Most notable among the outbreaks\\u000a are those involving norovirus illness and hepatitis A. Lessons learned from outbreak investigations indicate that most outbreaks\\u000a are preventable. Anthropogenic sources of contamination will continue to invade shellfish growing waters, and shellfish, by\\u000a their very nature, will continue to bioconcentrate these contaminants, including enteric
Gary P. Richards
Dengue virus infection causes dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS), whose pathogeneses are not clearly understood. Current hypotheses of antibody-dependent enhancement, virus virulence, and IFN-?\\/TNF?-mediated immunopathogenesis are insufficient to explain clinical manifestations of DHF\\/DSS such as thrombocytopenia and hemoconcentration. Dengue virus infection induces transient immune aberrant activation of CD4\\/CD8 ratio inversion and cytokine overproduction,
Huan-Yao Lei; Trai-Ming Yeh; Hsiao-Sheng Liu; Yee-Shin Lin; Shun-Hua Chen; Ching-Chuan Liu
Scientists have come one step closer to tracking outbreaks of bartonellosis, a potentially fatal vector-borne disease. Outbreaks of the disease, which was once thought to be found primarily in the high Andes Mountains of Peru, Ecuador, and Colombia, may be related to El Ni˜no events, according to researchers with NASA and the U.S. military.In findings reported on 17 January, climatology and disease prevention researchers said a study conducted in two regions in Peru points to a strong potential link between the 1997-1998 El Niño and an increase in sand flies, which are thought to be the disease host carriers.
Dengue often presents with non-specific clinical signs, and given the current paucity of accurate, rapid diagnostic laboratory tests, identifying easily obtainable bedside markers of dengue remains a priority. Previous studies in febrile Asian children have suggested that the combination of a positive tourniquet test (TT) and leucopenia can distinguish dengue from other febrile illnesses, but little data exists on the usefulness of these tests in adults or in the Americas. We evaluated the diagnostic accuracy of the TT and leucopenia (white blood cell count <5000/mm(3)) in identifying dengue as part of an acute febrile illness (AFI) surveillance study conducted in the Emergency Department of Saint Luke's Hospital in Ponce, Puerto Rico. From September to December 2009, 284 patients presenting to the ED with fever for 2-7 days and no identified source were enrolled. Participants were tested for influenza, dengue, leptospirosis and enteroviruses. Thirty-three (12%) patients were confirmed as having dengue; 2 had dengue co-infection with influenza and leptospirosis, respectively. An infectious etiology was determined for 141 others (136 influenza, 3 enterovirus, 2 urinary tract infections), and 110 patients had no infectious etiology identified. Fifty-two percent of laboratory-positive dengue cases had a positive TT versus 18% of patients without dengue (P<0.001), 87% of dengue cases compared to 28% of non-dengue cases had leucopenia (P<0.001). The presence of either a positive TT or leucopenia correctly identified 94% of dengue patients. The specificity and positive predictive values of these tests was significantly higher in the subset of patients without pandemic influenza A H1N1, suggesting improved discriminatory performance of these tests in the absence of concurrent dengue and influenza outbreaks. However, even during simultaneous AFI outbreaks, the absence of leucopenia combined with a negative tourniquet test may be useful to rule out dengue. PMID:22163057
Gregory, Christopher J; Lorenzi, Olga D; Colón, Lisandra; García, Arleene Sepúlveda; Santiago, Luis M; Rivera, Ramón Cruz; Bermúdez, Liv Jossette Cuyar; Báez, Fernando Ortiz; Aponte, Delanor Vázquez; Tomashek, Kay M; Gutierrez, Jorge; Alvarado, Luisa
Background Dengue fever is perhaps the most important viral re-emergent disease especially in tropical and sub-tropical countries, affecting about 50 million people around the world yearly. In Colombia, dengue virus was first detected in 1971 and still remains as a major public health issue. Although four viral serotypes have been recurrently identified, dengue virus type 2 (DENV-2) has been involved in the most important outbreaks during the last 20 years, including 2010 when the fatality rate highly increased. As there are no major studies reviewing virus origin and genotype distribution in this country, the present study attempts to reconstruct the phylogenetic history of DENV-2 using a sequence analysis from a 224 bp PCR-amplified product corresponding to the carboxyl terminus of the envelope (E) gene from 48 Colombian isolates. Results As expected, the oldest isolates belonged to the American genotype (subtype V), but the strains collected since 1990 represent the American/Asian genotype (subtype IIIb) as previously reported in different American countries. Interestingly, the introduction of this genotype coincides with the first report of dengue hemorrhagic fever in Colombia at the end of 1989 and the increase of cases during the next years. Conclusion After replacement of the American genotype, several lineages of American/Asian subtype have rapidly spread all over the country evolving in new clades. Nevertheless, the direct association of these new variants in the raise of lethality rate observed during the last outbreak has to be demonstrated.
This study is part of a program to control and prevent dengue in a slum bordering on the grounds of the Oswaldo Cruz Foundation in Rio de Janeiro, Brazil. The results obtained from a questionnaire and entomological survey called attention to problems pertaining to the information transmitted by public health campaigns and its interpretation, since many practices result from misunderstanding or forgetting preventive messages. Dengue-related data include most frequent vector breeding sites, people's knowledge, and dengue-related habits. The study's conclusions in terms of dengue prevention point to the need for drafting messages not only about ideal preventive practices but also teaching possible solutions: disseminating frequent messages throughout the year and not only seasonally and planning health education to join health professionals and the population in the search for sustainable dengue control alternatives. PMID:11035525
Lenzi, M F; Camillo-Coura, L; Grault, C E; Val, M B
Sera from patients involved in a Peruvian outbreak of dengue virus serotype 1 infection cross-neutralized the American genotype of dengue virus serotype 2 up to 100-fold more efficiently than they did the virulent Asian genotype of dengue virus serotype 2, as determined by a plaque reduction neutralization test (PRNT) with CV-1 fibroblasts modified to express human Fcgamma receptor CD32. The concordant preferential immune enhancement of the Asian genotype of dengue virus serotype 2 in human monocytes suggests that such a modification might strengthen the correlation between the PRNT titer and protection. PMID:19038781
Rodrigo, W W Shanaka I; Rodrigo, W W I S; Alcena, D C; Kou, Z; Kochel, T J; Porter, K R; Comach, G; Rose, R C; Jin, X; Schlesinger, J J
BackgroundDengue is a mosquito-borne viral disease caused by four closely related serotypes of Dengue viruses (DENVs). This disease whose symptoms range from mild fever to potentially fatal haemorrhagic fever and hypovolemic shock, threatens nearly half the global population. There is neither a preventive vaccine nor an effective antiviral therapy against dengue disease. The difference between severe and mild disease appears
Anil Babu Korrapati; Gokul Swaminathan; Aarti Singh; Navin Khanna; Sathyamangalam Swaminathan
The only way for dengue to spread in the human population is through the human-mosquito-human cycle. Most research in this field discusses the dengue-mosquito or dengue-human relationships over a particular study area, but few have explored the local spatial variations of dengue-mosquito and dengue-human relationships within a study area. This study examined whether spatial heterogeneity exists in these relationships. We used Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR) models to analyze spatial relationships and identify the geographical heterogeneities by using the information of entomology and dengue cases in the cities of Kaohsiung and Fengshan in 2002. Our findings indicate that dengue-mosquito and dengue-human relationships were significantly spatially non-stationary. This means that in some areas higher dengue incidences were associated with higher vector/host densities, but in some areas higher incidences were related to lower vector/host densities. We demonstrated that a GWR model can be used to geographically differentiate the relationships of dengue incidence with immature mosquito and human densities. This study provides more insights into spatial targeting of intervention and control programs against dengue outbreaks within the study areas.
Lin, Chia-Hsien; Wen, Tzai-Hung
In the study of vaccines for dengue viruses, which are multivalent immunization, genetically and antigenically distinct, we\\u000a should have more sophisticated understanding of viral immune physiology. Because the immune response to dengue and its role\\u000a in the pathophysiology of dengue fever and dengue hemorrhagic fever are multifaceted, several different efforts have been\\u000a made to engineer a protective vaccine. Because of
Xiaofang Wang; Xiaoxia Huang; Shiwen Wang
Animal models of dengue virus disease have been very difficult to develop because of the virus' specificity for infection and replication in certain human cells. We developed a model of dengue fever in immunodeficient mice transplanted with human stem cells from umbilical cord blood. These mice show measurable signs of dengue disease as in humans (fever, viremia, erythema and thrombocytopenia),
Javier Mota; Rebeca Rico-Hesse
Aedes aegypti was eliminated from Brazil in 1955, but re-infested the country in the 1970s. Dengue outbreaks have occurred since 1981 and became endemic in several cities in Brazil after 1986. Urban yellow fever has not occurred since 1942, and only jungle yellow fever cases have been reported. A population genetic analysis using isoenzyme variation combined with an evaluation of
R Lourenço-de-Oliveira; M Vazeille; A. M. B de Filippis; A. B Failloux
Background Dengue is a major health problem in tropical and subtropical regions. In Colombia, dengue viruses (DENV) cause about 50,000 cases annually, 10% of which involve Dengue Haemorrhagic Fever/Dengue Shock Syndrome. The picture is similar in other surrounding countries in the Americas, with recent outbreaks of severe disease, mostly associated with DENV serotype 3, strains of the Indian genotype, introduced into the Americas in 1994. Results The analysis of the 3'end (224 bp) of the envelope gene from 32 DENV-3 strains recently recovered in Colombia confirms the circulation of the Indian genotype, and surprisingly the co-circulation of an Asian-Pacific genotype only recently described in the Americas. Conclusion These results have important implications for epidemiology and surveillance of DENV infection in Central and South America. Molecular surveillance of the DENV genotypes infecting humans could be a very valuable tool for controlling/mitigating the impact of the DENV infection.
Usme-Ciro, Jose A; Mendez, Jairo A; Tenorio, Antonio; Rey, Gloria J; Domingo, Cristina; Gallego-Gomez, Juan C
A serosurvey carried out in 2006 in Mayotte, a French overseas collectivity in the Indian Ocean, confirmed previous circulation of dengue virus (DENV) on the island, but since the set up of a laboratory-based surveillance of dengue-like illness in 2007, no case of DENV has been confirmed. In response to an outbreak of DENV-3 on Comoros Islands in March 2010 surveillance of dengue-like illness in Mayotte was enhanced. By September 15, 76 confirmed and 31 probable cases of DENV have been identified in Mayotte. In urban and periurban settings on the island, Aedes albopictus is the predominant Aedes species, but Ae. aegyptii remains the most common species in rural areas. Given the epidemic potential of dengue virus in Mayotte, adequate monitoring including early detection of cases, timely investigation and sustained mosquito control actions remain essential. PMID:22066303
Lernout, T; Giry, C; Binder, P; Zumbo, B; Durquety, E; Lajoinie, G; D'Ortenzio, E; Filleul, L
The efficacy of tulathromycin in the treatment (phase 1) and prevention (phase 2) of bovine respiratory disease (BRD) was evaluated on commercial farms in France, Germany, Italy, and Spain. In phase 1, commingled cattle with clinical BRD were treated with tulathromycin (n = 128) or florfenicol (n = 125) on day 0. Similar percentages of animals showed sustained clinical improvement at day 14 (tulathromycin 83.3% versus florfenicol 81.0%) and had not relapsed by day 60 (tulathromycin 63.3% versus florfenicol 58.4%). In phase 2, healthy in-contact cattle were treated with tulathromycin (n = 492), tilmicosin (n = 494), or saline (n = 265) on day 0. Significantly more (P = .0001) tulathromycin-treated cattle remained healthy to day 14 (92.4%) than tilmicosin-treated (83.7%) or saline-treated (63.7%) cattle, and this was maintained through day 60 (tulathromycin 85.4% versus tilmicosin 75.1% and saline 56.2%). Tulathromycin was highly effective in the treatment and prevention of BRD. PMID:16094560
Godinho, Kevin S; Wolf, Regina M-L G; Sherington, John; Rowan, Tim G; Sunderland, Simon J; Evans, Nigel A
Dengue has emerged as a major public health problem worldwide. Dengue virus infection causes a wide range of clinical manifestations. Since the 1970s, clinical dengue has been classified according to the World Health Organization guideline as dengue fever and dengue hemorrhagic fever. The classification has been criticized with regard to its usefulness and its applicability. In 2009, the World Health Organization issued a new guideline that classifies clinical dengue as dengue and severe dengue. The 2009 classification differs significantly from the previous classification in both conceptual and practical levels. The impacts of the new classification on clinical practice, dengue research, and public health policy are discussed.
Rothman, Alan L.; Gibbons, Robert V.; Sittisombut, Nopporn; Malasit, Prida; Ennis, Francis A.; Nimmannitya, Suchitra; Kalayanarooj, Siripen
Six human beings were inoculated with dengue and developed typical disease. Two of these were reinoculated and proved immune. The remaining four were later inoculated with Colorado tick fever. Three developed typical disease. The fourth, who remained well, has previously lived in an endemic area (Colorado). One patient was inoculated with Colorado tick fever first and later with dengue. He developed both diseases. Colorado tick fever and dengue do not give a cross-immunity. Hamsters can be infected with Colorado tick fever but not with dengue. Colorado tick fever and dengue appear to be distinct disease entities.
Florio, Lloyd; Hammon, William McD.; Laurent, Angela; Stewart, Mabel O.
Dengue is a tropical disease affecting 110 countries throughout the world and placing over 3 billion people at risk of infection. According the World Health Organization 70 to 500 million persons are infected every year including 2 million who develop hemorrhagic form and 20,000 who die. Children are at highest risk for death. Due to the absence of specialized laboratories in most endemic regions and to the lack of specifici clinical presentation, the incidence of dengue and its economic costs are certainly underestimated. Dengue iscaused by an arbovirus belonging to the Flavivirus genus of the family Flaviviridae. There are four dengue virus serotypes and no cross protection between them. The disease is transmitted through the bites of mosquitoes belonging to the Aedes genus, mainly Aedes aegypti. However A. albopictus has played an important role in the spread of the disease and other species may be involved in specific locations (e.g., A. polynesiensis in the South Pacific). There is no specific treatment for dengue. Management of severe forms depends on symptomatic treatment of hemorrhagic complications and hypovolemic shock. Prevention requires control of vector mosquitoes that is difficult to implement and maintain. Dengue is a major emerging infectious disease with a heavy impact on public health. The high human and economic costs as well as the absence of specific preventive measures underscore the need to develop a vaccine. However finding and distributing such a vaccine to populations at risk is hampered by numerous obstacles. The most notable challenges standing in the way of development of a candidate vaccine are as follows: absence of an animal model, which has important implications for the preclinical development strategy; need to develop a live attenuated vaccine; existence of 4 antigenically distinct serotypes with the resulting risk of competition between vaccine strains; immunologic risks related to antibody-dependent enhancement that has been hypothesized to be the cause of severe forms of the illness; absence of a well defined correlate of protection and preexisting vaccine, which will require the organization of large-scale pre-clinical trials to demonstrate the efficacy of the virus; complexity associated with industrial production of a tetravalent vaccine. Development and production of a safe and reliable vaccine are only the first steps to ensuring protection of the populations at risk, It twill also be necessary to identify and take into account a variety of geographic, economic, regulatory, and logistic factors: The epidemiological profile of dengue is variable. For example the age at which the likelihood of developing the disease is highest is not the same in Asia and Latin America. Vaccination programs must be tailored to regional and national epidemiological specificities. Introduction of dengue vaccination in the national immunization programs must take into account the special features of each country without jeopardizing the existing vaccines already in use. The need for an additional visit can represent a hardship both economically and logistically. Alternative funding will be needed to finance vaccination programs in some countries located in endemic zones, Long-term phase 4 effectiveness and tolerance field studies must be planned in collaboration with national authorities. All these challenges and obstacles have been taken into account in the development of Sanofi Pasteur's live attenuated tetravalent vaccine. Research for development of a dengue vaccine began during the 1990s. Clinical studies with the most promising tetravalent vaccine were started in the 2000s. A trial carried out in adults in the United States has shown that administration of three doses of the tetravalent candidate vaccine was 100% successful in inducing an antibody response capable of neutralizing all four dengue virus serotypes. Phase II clinical trials are now under way in children and adults in Mexico, Peru, and the Philippines. The first efficacy trial in children began in Thailand in February 2009. The purp
Background Maternal dengue antibodies are considered to play a significant role in dengue pathogenesis among infants. Determining the transplacental specific antibody transfer is invaluable for establishing the optimal vaccination age among infants in endemic regions. Methods We conducted a cross-sectional study among pairs of maternal and corresponding umbilical cord blood samples in public hospitals. The prevalence and incidence of dengue infection were determined in 505 pairs of pregnant women and neonates during a large outbreak (2009–2010) in central Brazil. The women were interviewed at late pregnancy to assess current or past symptoms of dengue. All parturients and their neonates were screened using Dengue IgG Indirect ELISA (Panbio) to assess previous dengue exposure. A semi-quantitative measurement of the IgG antibody expressed by the index ratio was calculated using optical density (OD) values according to the manufacturer’s instructions. The studied population of parturients and their offspring was also screened for recent dengue infection by the Dengue IgM-capture ELISA (Panbio). Those participants with history of fever and two or more symptoms of dengue at least 10 days before the delivery were also tested for the dengue NS1 antigen using the Dengue Early ELISA (Panbio) and RT-PCR. Results The mean maternal age was 25.8 (SD?=?6.4), and 83.6% of deliveries were between 37 and 41 weeks. Approximately half of the 505 women and neonates were IgG-seropositive, yielding 99.3% co-positive mother-child frequency of antibody transfer (Kappa?=?0.96). The incidence of dengue infection was 2.8% (95% CI 1.4–4.4%) among the women considering 14 IgM-positive results and one DENV2 detected by RT-PCR. The dengue NS1 antigen was undetectable in the matched pairs. Conclusion This study provides critical data on the prevalence of transplacental transferred maternal-infant anti-dengue antibodies and incidence of infection. The design of future vaccine trials should consider diverse regional epidemiological scenarios.
Objective. To determine the prevalence of leptospirosis in patients from Veracruz with initial diagnosis of dengue and its association with risk factors. Materials and Methods. Transversal study in patients who sought medical attention under the suspicion of dengue. Backgrounds were researched and blood samples were drawn to determine dengue (NS1, RT-PCR) and leptospirosis (IFI). Simple frequencies, central tendency and dispersion measures, and prevalence and trust intervals at 95% (IC95%) were obtained. Prevalence reasons (RP) and IC95% were obtained and a multivariate logistic model was applied, using SPSS?V15. Results. 171 patients were included, 56% women (32 ± 14 years) and 44% men (32 ± 17 years). 48% of the cases (IC95%?40.5–55.4) was positive to dengue, with a cut point of 1?:?80, seroprevalence for leptospirosis was of 6% (IC95%?2.7–10); 12% (IC95%?7–16.5) was positive to both pathologies and 34% was negative to both tests. Although the largest number of isolations corresponded to serotype 2, the four dengue virus serotypes were identified. In the bivariate analysis, overcrowding RP?=?1.33, (IC?=?0.46–3.5), bathing in rivers (RP?=?1.31, IC?=?0.13–7.4), and walking barefoot (RP?=?1.39, IC?=?0.58–3.3) were the variables associated with leptospirosis, although the relation was not statistically significant. Conclusions. Leptospirosis prevalence in subjects under suspicion of dengue fever is high, as well as the coincidence of both infections. The results show the coexistence of overlapped outbreaks of several diseases sharing the side of transmission. It is necessary the intentional search of other pathologies, such as influenza, rickettsiosis, and brucella, among others.
Dircio Montes Sergio, A.; Gonzalez Figueroa, E.; Maria Saadia, Verdalet Guzman; Elizabeth, Soler Huerta; Beatriz, Rivas Sanchez; Altuzar Aguilar Victor, M.; Navarrete Espinosa, J.
Objective. To determine the prevalence of leptospirosis in patients from Veracruz with initial diagnosis of dengue and its association with risk factors. Materials and Methods. Transversal study in patients who sought medical attention under the suspicion of dengue. Backgrounds were researched and blood samples were drawn to determine dengue (NS1, RT-PCR) and leptospirosis (IFI). Simple frequencies, central tendency and dispersion measures, and prevalence and trust intervals at 95% (IC95%) were obtained. Prevalence reasons (RP) and IC(95%) were obtained and a multivariate logistic model was applied, using SPSS?V15. Results. 171 patients were included, 56% women (32 ± 14 years) and 44% men (32 ± 17 years). 48% of the cases (IC95%?40.5-55.4) was positive to dengue, with a cut point of 1?:?80, seroprevalence for leptospirosis was of 6% (IC(95%)?2.7-10); 12% (IC95%?7-16.5) was positive to both pathologies and 34% was negative to both tests. Although the largest number of isolations corresponded to serotype 2, the four dengue virus serotypes were identified. In the bivariate analysis, overcrowding RP?=?1.33, (IC?=?0.46-3.5), bathing in rivers (RP?=?1.31, IC?=?0.13-7.4), and walking barefoot (RP?=?1.39, IC?=?0.58-3.3) were the variables associated with leptospirosis, although the relation was not statistically significant. Conclusions. Leptospirosis prevalence in subjects under suspicion of dengue fever is high, as well as the coincidence of both infections. The results show the coexistence of overlapped outbreaks of several diseases sharing the side of transmission. It is necessary the intentional search of other pathologies, such as influenza, rickettsiosis, and brucella, among others. PMID:22685476
Dircio Montes Sergio, A; González Figueroa, E; María Saadia, Verdalet Guzmán; Elizabeth, Soler Huerta; Beatriz, Rivas Sánchez; Altuzar Aguilar Víctor, M; Navarrete Espinosa, J
Dengue represents a substantial burden in many tropical and sub-tropical regions of the world. We estimated the economic burden of dengue illness in Malaysia. Information about economic burden is needed for setting health policy priorities, but accurate estimation is difficult because of incomplete data. We overcame this limitation by merging multiple data sources to refine our estimates, including an extensive literature review, discussion with experts, review of data from health and surveillance systems, and implementation of a Delphi process. Because Malaysia has a passive surveillance system, the number of dengue cases is under-reported. Using an adjusted estimate of total dengue cases, we estimated an economic burden of dengue illness of US$56 million (Malaysian Ringgit MYR196 million) per year, which is approximately US$2.03 (Malaysian Ringgit 7.14) per capita. The overall economic burden of dengue would be even higher if we included costs associated with dengue prevention and control, dengue surveillance, and long-term sequelae of dengue. PMID:23033404
Shepard, Donald S; Undurraga, Eduardo A; Lees, Rosemary Susan; Halasa, Yara; Lum, Lucy Chai See; Ng, Chiu Wan
Dengue disease is becoming a huge public health concern around the world as more than one-third of the world's population living in areas at risk of infection. In an effort to assess host factors interacting with dengue virus, we identified claudin-1, a major tight junction component, as an essential cell surface protein for dengue virus entry. When claudin-1 was knocked down in Huh 7.5 cells via shRNA, the amount of dengue virus entering host cells was reduced. Consequently, the progeny virus productions were decreased and dengue virus-induced CPE was prevented. Furthermore, restoring the expression of claudin-1 in the knockdown cells facilitated dengue virus entry. The interaction between claudin-1 and dengue viral prM protein was further demonstrated using the pull-down assay. Deletion of the extracellular loop 1 (ECL1) of claudin-1 abolished such interaction, so did point mutations C54A, C64A and I32M on ECL1. These results suggest that the interaction between viral protein prM and host protein claudin-1 was essential for dengue entry. Since host and viral factors involved in virus entry are promising therapeutic targets, determining the essential role of claudin-1 could lead to the discovery of entry inhibitors with attractive therapeutic potential against dengue disease. PMID:24074594
Che, Pulin; Tang, Hengli; Li, Qianjun
Prevention and containment of outbreaks requires examination of the contribution and interrelation of outbreak causative events. An outbreak fault tree was developed and applied to 61 enteric outbreaks related to public drinking water supplies in the EU. A mean of 3.25 causative events per outbreak were identified; each event was assigned a score based on percentage contribution per outbreak. Source and treatment system causative events often occurred concurrently (in 34 outbreaks). Distribution system causative events occurred less frequently (19 outbreaks) but were often solitary events contributing heavily towards the outbreak (a mean % score of 87.42). Livestock and rainfall in the catchment with no/inadequate filtration of water sources contributed concurrently to 11 of 31 Cryptosporidium outbreaks. Of the 23 protozoan outbreaks experiencing at least one treatment causative event, 90% of these events were filtration deficiencies; by contrast, for bacterial, viral, gastroenteritis and mixed pathogen outbreaks, 75% of treatment events were disinfection deficiencies. Roughly equal numbers of groundwater and surface water outbreaks experienced at least one treatment causative event (18 and 17 outbreaks, respectively). Retrospective analysis of multiple outbreaks of enteric disease can be used to inform outbreak investigations, facilitate corrective measures, and further develop multi-barrier approaches. PMID:17890833
Risebro, Helen L; Doria, Miguel F; Andersson, Yvonne; Medema, Gertjan; Osborn, Keith; Schlosser, Olivier; Hunter, Paul R
Dengue has been present in the Americas for centuries, but the current situation is dynamic, and is worsening. The main vector, Aedes aegypti, infests most countries. Vector control efforts have been largely inadequate. Population growth, especially in urban, low latitude areas, has resulted in a greater risk for contact with a competent vector. An increasing number of cities have reached
Mary E Wilson; Lin H Chen
Dengue is the most important arthropod-borne viral disease, it is characterized by mild symptoms to hemorrhagic manifestations and shock syndrome (DHF/DSS). Dengue and DHF/DSS have become major public health problems worldwide. In the urban areas of tropical and subtropical regions approximately 50 million infections occur annually. In Venezuela the situation is similar to the rest of the Americas. The impact of dengue points out the necessity of very organized and effective control programs. The emergency measures to combat the epidemics have had limited effects. There is not a specific management of dengue infections, no vaccine is commercially available and vector control is one of the alternatives to stop the spread of the disease, but an integral control program is needed, with each population's particularities and the state of epidemic risk in that it is. In the practice, it is to combine the environmental reparation with the changes in the human behavior taken place by the sanitary education and the necessary laws for it, integrated with the biological fight against the vector in the way and more appropriate moment and the chemical control in epidemic situations. This last aspect is fundamental as message of change toward an active attitude and of conscience, without which we can affirm with all security that doesn't exist government neither system of health able to solve this problem. PMID:12229276
Identification of Chimpanzee Fab Fragments by Repertoire Cloning and Production of a Full-Length Humanized Immunoglobulin G1 Antibody That Is Highly Efficient for Neutralization of Dengue Type 4 Virus
A safe and effective dengue vaccine is still not available. Passive immunization with monoclonal antibodies from humans or nonhuman primates represents an attractive alternative for the prevention of dengue virus infection. Fab monoclonal antibodies to dengue type 4 virus (DENV-4) were recovered by repertoire cloning of bone marrow mRNAs from an immune chimpanzee and analyzed for antigen binding specificity, VH
Ruhe Men; Tetsu Yamashiro; Ana P. Goncalvez; Claire Wernly; Darren J. Schofield; Suzanne U. Emerson; Robert H. Purcell; Ching-Juh Lai
Dengue virus infection causes dengue fever, dengue haemorrhagic fever and dengue shock syndrome. No animal model is available that mimics these clinical manifestations. In this study, the establishment is reported of a murine model for dengue virus infection that resembles the thrombocytopenia manifestation. Dengue-2 virus (dengue virus type 2) can infect murine cells either in vitro (primary cell culture) or
Kao-Jean Huang; Shu-Yi J. Li; Shiour-Ching Chen; Hsiao-Sheng Liu; Yee-Shin Lin; Trai-Ming Yeh; Ching-Chuan Liu; Huan-Yao Lei
... FDA's CORE: A Food Safety Network; CORE Network Background Paper; Consumer Update: Rapid Response Helps Contain Outbreak Linked to ... More results from www.fda.gov/food/recalls,%20outbreaks%20&%20emergencies/outbreaks
Dengue disease is an increasing global health problem that threatens one-third of the world's population. To control this emerging arbovirus, an efficient preventive vaccine is still needed. Because four serotypes of dengue virus (DV) coexist and antibody-dependent enhanced infection may occur, most strategies developed so far rely on the administration of tetravalent formulations of four live attenuated or chimeric viruses. Here, we evaluated a new strategy based on the expression of a single minimal tetravalent DV antigen by a single replicating viral vector derived from pediatric live-attenuated measles vaccine (MV). We generated a recombinant MV vector expressing a DV construct composed of the four envelope domain III (EDIII) from the four DV serotypes fused with the ectodomain of the membrane protein (ectoM). After two injections in mice susceptible to MV infection, the recombinant vector induced neutralizing antibodies against the four serotypes of dengue virus. When immunized mice were further inoculated with live DV from each serotype, a strong memory neutralizing response was raised against all four serotypes. A combined measles-dengue vaccine might be attractive to immunize infants against both diseases where they co-exist. PMID:20688034
Brandler, Samantha; Ruffie, Claude; Najburg, Valérie; Frenkiel, Marie-Pascale; Bedouelle, Hughes; Desprès, Philippe; Tangy, Frédéric
Dengue is a systemic arthropod-borne viral disease of major global public health importance. At least 2.5 billion people who live in areas of the world where dengue occurs are at risk of developing dengue fever (DF) and its severe complications, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Repeated reemergences of dengue in sudden explosive epidemics often cause public alarm and seriously stress healthcare systems. The control of dengue is further challenged by the lack of effective therapies, vaccines, and point-of-care diagnostics. Despite years of study, even its pathogenic mechanisms are poorly understood. This article discusses recent advances in dengue research and identifies challenging gaps in research on dengue clinical evaluation, diagnostics, epidemiology, immunology, therapeutics, vaccinology/clinical trials research, vector biology, and vector ecology. Although dengue is a major global tropical pathogen, epidemiologic and disease control considerations in this article emphasize dengue in the Americas. PMID:22782946
Laughlin, Catherine A; Morens, David M; Cassetti, M Cristina; Costero-Saint Denis, Adriana; San Martin, Jose-Luis; Whitehead, Stephen S; Fauci, Anthony S
Dengue is a systemic arthropod-borne viral disease of major global public health importance. At least 2.5 billion people who live in areas of the world where dengue occurs are at risk of developing dengue fever (DF) and its severe complications, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Repeated reemergences of dengue in sudden explosive epidemics often cause public alarm and seriously stress healthcare systems. The control of dengue is further challenged by the lack of effective therapies, vaccines, and point-of-care diagnostics. Despite years of study, even its pathogenic mechanisms are poorly understood. This article discusses recent advances in dengue research and identifies challenging gaps in research on dengue clinical evaluation, diagnostics, epidemiology, immunology, therapeutics, vaccinology/clinical trials research, vector biology, and vector ecology. Although dengue is a major global tropical pathogen, epidemiologic and disease control considerations in this article emphasize dengue in the Americas.
Laughlin, Catherine A.; Morens, David M.; Cassetti, M. Cristina; Costero-Saint Denis, Adriana; San Martin, Jose-Luis; Whitehead, Stephen S.; Fauci, Anthony S.
\\u000a Infection with one of the four serotypes of dengue virus (DENV) causes a wide spectrum of clinical disease ranging from asymptomatic\\u000a infection, undifferentiated fever, dengue fever (DF) to dengue hemorrhagic fever (DHF). DHF occurs in a minority of patients\\u000a and is characterized by bleeding and plasma leakage which may lead to shock. There are currently no reliable clinical or laboratory
Anon Srikiatkhachorn; Sharone Green
Dengue is one of the most important emerging vector-borne viral diseases. There are four serotypes of dengue viruses (DENV), each of which is capable of causing self-limited dengue fever (DF) or even life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The major clinical manifestations of severe DENV disease are vascular leakage, thrombocytopenia, and hemorrhage, yet the detailed mechanisms are not fully resolved. Besides the direct effects of the virus, immunopathological aspects are also involved in the development of dengue symptoms. Although no licensed dengue vaccine is yet available, several vaccine candidates are under development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, and live recombinant, DNA and subunit vaccines. The live attenuated virus vaccines and live chimeric virus vaccines are undergoing clinical evaluation. The other vaccine candidates have been evaluated in preclinical animal models or are being prepared for clinical trials. For the safety and efficacy of dengue vaccines, the immunopathogenic complications such as antibody-mediated enhancement and autoimmunity of dengue disease need to be considered.
Dengue fever is a common tropical infection. This acute febrile illness can be a deadly infection in cases of severe manifestation, causing dengue hemorrhagic shock. In this brief article, I will summarize and discuss the diagnosis and treatment of this disease. For diagnosis of dengue, most tropical doctors make use of presumptive diagnosis; however, the definite diagnosis should be based on immunodiagnosis or viral study. Focusing on treatment, symptomatic and supportive treatment is the main therapeutic approach. The role of antiviral drugs in the treatment of dengue fever has been limited, but is currently widely studied. PMID:20586568
Background: Invasive listeriosis is a potentially fatal foodborne disease caused by Listeria monocytogenes. In February 2010, a listeriosis cluster was identified in Texas. We investigated to confirm the outbreak, identify the source, and prevent additional infections. Methods: All clinical isol...
Summary Achievements in malaria control could inform efforts to control the increasing global burden of dengue. Better methods for quantifying dengue endemicity—equivalent to parasite prevalence surveys and endemicity mapping used for malaria—would help target resources, monitor progress, and advocate for investment in dengue prevention. Success in controlling malaria has been attributed to widespread implementation of interventions with proven efficacy. An improved evidence base is needed for large-scale delivery of existing and novel interventions for vector control, alongside continued investment in dengue drug and vaccine development. Control of dengue is unlikely to be achieved without coordinated international financial and technical support for national programmes, which has proven effective in reducing the global burden of malaria.
Anders, Katherine L; Hay, Simon I
Achievements in malaria control could inform efforts to control the increasing global burden of dengue. Better methods for quantifying dengue endemicity-equivalent to parasite prevalence surveys and endemicity mapping used for malaria-would help target resources, monitor progress, and advocate for investment in dengue prevention. Success in controlling malaria has been attributed to widespread implementation of interventions with proven efficacy. An improved evidence base is needed for large-scale delivery of existing and novel interventions for vector control, alongside continued investment in dengue drug and vaccine development. Control of dengue is unlikely to be achieved without coordinated international financial and technical support for national programmes, which has proven effective in reducing the global burden of malaria. PMID:23174383
Anders, Katherine L; Hay, Simon I
In October 2010, the Ministry of Public Health and Population reported an outbreak of dengue-like acute febrile illness in Al Hodayda governorate. By January 2011, a total of 1542 cases had been recorded from 19 of the 26 districts in the governorate with 104 purportedly associated deaths. In response this event, in January 2011 entomological investigations aimed at identifying the primary vector and the epidemic associated etiological agent were carried out. Based on the reported cases and the progress of the outbreak in the governorate, mosquito collection was undertaken in two of the most recent outbreak areas; Al Khokha district (130km south of Al Hodayda) and Al Muneera district (100km north). Mosquito adults were collected from houses using BG-sentinel™ traps, aspiration of resting mosquitoes and knock-down spraying. Indoor and outdoor containers adjacent to the houses were inspected for larvae. Subsequently mosquito pools were analyzed by RT-PCR for detection of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, DENV-4), and for Chikungunya virus (CHIKV). Aedes aegypti was the dominant mosquito species collected. Four pools represent 40% of the tested pools, all containing adult female Ae. aegypti, were positive for CHIKV. Three CHIKV isolates were obtained from the RNA positive mosquito pools and identified by rRT-PCR. This finding marks the first record of CHIKV isolated from Ae. aegypti in Yemen. The larval container and Breteau indices in the visited localities surveyed were estimated at 53.8 and 100, respectively. The emergence of this unprecedented CHIKV epidemic in Al Hodayda is adding up another arboviral burden to the already existing vector-borne diseases. Considering the governorate as one focal port in the Red Sea region, the spread of the disease to other areas in Yemen and in neighboring countries is anticipated. Public health education and simple measures to detect and prevent mosquito breeding in water storage containers could prevent and reduce the spread of mosquito-borne viruses like CHIKV and DENV in Yemen. PMID:22469818
Zayed, Alia; Awash, Abdullah A; Esmail, Mohammed A; Al-Mohamadi, Hani A; Al-Salwai, Mostafa; Al-Jasari, Adel; Medhat, Iman; Morales-Betoulle, Maria E; Mnzava, Abraham
Aim To investigate maternal and perinatal outcomes (maternal death, preterm delivery, low birth weight and perinatal mortality) of dengue at PortSudan and Elmawani hospitals in the eastern Sudan. Method This was a retrospective Cohort study where medical files of women with dengue were reviewed. Results There were 10820 deliveries and 78 (0.7%) pregnant women with confirmed dengue IgM serology at the mean (SD) gestational age of 29.4(8.2) weeks. While the majority of these women had dengue fever (46, 58.9%), hemorrhagic fever and dengue shock syndrome were the presentations in 18 (23.0%) and 12, (15.3%) of these women, respectively. There were 17(21.7%) maternal deaths. Fourteen (17.9%) of these 78 women had preterm deliveries and 19 (24.3%) neonates were admitted to neonatal intensive care unit. Nineteen (24.3%) women gave birth to low birth weight babies. There were seven (8.9%) perinatal deaths. Eight (10.2%) patients delivered by caesarean section due to various obstetrical indications. Conclusion Thus dengue has poor maternal and perinatal outcomes in this setting. Preventive measures against dengue should be employed in the region, and more research on dengue during pregnancy is needed.
The use of vector surveillance tools for preventing dengue disease requires fine assessment of risk, in order to improve vector control activities. Nevertheless, the thresholds between vector detection and dengue fever occurrence are currently not well established. In Belo Horizonte (Minas Gerais, Brazil), dengue has been endemic for several years. From January 2007 to June 2008, the dengue vector Aedes (Stegomyia) aegypti was monitored by ovitrap, the sticky-trap MosquiTRAP™ and larval surveys in an study area in Belo Horizonte. Using a space-time scan for clusters detection implemented in SaTScan software, the vector presence recorded by the different monitoring methods was evaluated. Clusters of vectors and dengue fever were detected. It was verified that ovitrap and MosquiTRAP vector detection methods predicted dengue occurrence better than larval survey, both spatially and temporally. MosquiTRAP and ovitrap presented similar results of space-time intersections to dengue fever clusters. Nevertheless ovitrap clusters presented longer duration periods than MosquiTRAP ones, less acuratelly signalizing the dengue risk areas, since the detection of vector clusters during most of the study period was not necessarily correlated to dengue fever occurrence. It was verified that ovitrap clusters occurred more than 200 days (values ranged from 97.0±35.35 to 283.0±168.4 days) before dengue fever clusters, whereas MosquiTRAP clusters preceded dengue fever clusters by approximately 80 days (values ranged from 65.5±58.7 to 94.0±14. 3 days), the former showing to be more temporally precise. Thus, in the present cluster analysis study MosquiTRAP presented superior results for signaling dengue transmission risks both geographically and temporally. Since early detection is crucial for planning and deploying effective preventions, MosquiTRAP showed to be a reliable tool and this method provides groundwork for the development of even more precise tools.
de Melo, Diogo Portella Ornelas; Scherrer, Luciano Rios; Eiras, Alvaro Eduardo
Many countries in Central and South America as well as Brazil have been characterized by a rise in dengue endemicity. Since 1986, dengue infection has gained endemicity in these countries and more than 3 million dengue cases have been reported along with the emergence also of the severe forms of the disease. Once intratypic variations among dengue virus (DEN) serotypes
Marize Pereira Miagostovich; Flávia Barreto dos Santos; Rita Maria Ribeiro Nogueira
The medical literature contains only a few reports of rhabdomyolysis occurring in patients with dengue fever. We report the case of a 25-year-old Jamaican man who was admitted to a private hospital four days after the onset of an acute febrile illness with fever, myalgia, and generalized weakness. Dengue fever was confirmed with a positive test for the dengue antigen, nonstructural protein 1. He remained well and was discharged on day 6 of his illness. On day 8, he started to pass red urine and was subsequently admitted to the University Hospital of the West Indies. On admission he was found to have myoglobinuria and an elevated creatine phosphokinase (CPK) of 325,600?U/L, leading to a diagnosis of rhabdomyolysis. Dengue IgM was positive. He was treated with aggressive hydration and had close monitoring of his urine output, creatinine, and CPK levels. His hospital course was uneventful without the development of acute renal failure and he was discharged after 14 days in hospital, with a CPK level of 2463?U/L. This case highlights that severe rhabdomyolysis may occur in patients with dengue fever and that early and aggressive treatment may prevent severe complications such as acute renal failure and death.
Sargeant, Tanya; Harris, Tricia; Wilks, Rohan; Barned, Sydney; Galloway-Blake, Karen; Ferguson, Trevor
To determine the frequency and the natural history of neurological manifestations of dengue infection in Thai children, 1,493 children diagnosed with dengue infection by serology and admitted to the Department of Pediatrics, Chulalongkorn Hospital, Bangkok, Thailand from 1987 to 1998 were reviewed from prospectively recorded medical charts. There were 80 chil- dren identified with neurological manifestations, an incidence of 5.4%
Dengue viral infections affect up to 100 million individuals per year. Dengue haemorrhagic fever is a clinical form of disease characterised by intravascular fluid loss. There has been a marked increase in the incidence of this form of the disease over the last few decades, associated with significant mortality, particularly in the paediatric population. A number of theories relating to
William J. H McBride; Helle Bielefeldt-Ohmann
Dengue fever is an emerging mosquito-borne flaviviral disease that threatens 2.5 billion people worldwide. No clinically approved vaccine and antiviral therapy are currently available to prevent or treat dengue virus (DENV) infection. Vertebrate animals other than primates are not normally infectable with DENV; however, a small animal dengue infection model would greatly facilitate the development of a vaccine or an antiviral therapy. To this end, a rodent model for DENV infection has been established in IFN-?/? and IFN-? receptor-deficient (AG129) mice. This chapter describes the protocol for the DENV infection model in AG129 mice and testing of antiviral compounds by oral gavage or parenteral injection. PMID:23821275
Schul, Wouter; Yip, Andy; Shi, Pei-Yong
Dengue virus infection may remain asymptomatic or manifest as nonspecific viral infection to life threatening dengue hemorrhagic\\u000a fever (DHF)\\/dengue shock syndrome (DSS). Patients with DHF\\/DSS have fever, hemorrhagic manifestations along with thrombocytopenia\\u000a and hemoconcentration. Thrombocytopenia and hemoconcentration are distinguishing features between DHF\\/DSS and dengue fever\\u000a (DF). Some patients with dengue fever may have significant bleed and mild thrombocytopenia but no
S. K. Kabra; Y. Jain; T. Singhal; V. H. Ratageri
Vaccination with plasmid DNA against infectious pathogens including dengue is an active area of investigation. By design, DNA vaccines are able to elicit both antibody responses and cellular immune responses capable of mediating long-term protection. Great technical improvements have been made in dengue DNA vaccine constructs and trials are underway to study these in the clinic. The scope of this review is to highlight the rich history of this vaccine platform and the work in dengue DNA vaccines accomplished by scientists at the Naval Medical Research Center. This work resulted in the only dengue DNA vaccine tested in a clinical trial to date. Additional advancements paving the road ahead in dengue DNA vaccine development are also discussed. PMID:21777640
Danko, Janine R; Beckett, Charmagne G; Porter, Kevin R
Despite many successes in the field of vaccinology over the past century, several important scourges for which effective vaccines remain elusive continue to be threats to public health. The mosquito-borne dengue virus causes millions of infections in tropical and subtropical regions throughout the world, and is responsible for an annual mortality that measures in the thousands. The ubiquitous presence of dengue virus, and its potentially lethal complications, have made the development of an effective vaccine against the virus a priority. However, before such a vaccine can be created, the basic immunology surrounding dengue infection must be clarified. Such research is underway, including efforts focusing on the response of T-cells and the potentially central role of this response in dengue pathophysiology. 'Shaping' the T-cell response may be the key to successful dengue vaccine design. PMID:18175262
Hatch, Steven; Mathew, Anuja; Rothman, Alan
Dengue hemorrhagic fever leading to hemorrhage in pituitary adenoma is not reported till date: We herein report the first case of bilateral visual loss secondary to pituitary adenoma hemorrhage associated with dengue hemorrhagic fever. Urgent transnasal trans sphenoidal decompression of the macroadenoma prevented permanent visual loss in this patient. Pituitary apoplexy should be considered as differential diagnosis of visual deterioration apart from retinal hemorrhage, maculopathy, and optic neuropathy in cases of dengue hemorrhagic fever. Early decompression of optic nerves helped in the restoration of vision.
Kumar, Vimal; Kataria, Rashim; Mehta, V S
We examined outbreak investigations conducted around the world from 1988 to 1999 by the Centers for Disease Control and Prevention’s Epidemic Intelligence Service. In 44 (4.0%) of 1,099 investigations, identified causative agents had bioterrorism potential. In six investigations, intentional use of infectious agents was considered. Healthcare providers reported 270 (24.6%) outbreaks and infection control practitioners reported 129 (11.7%); together they reported 399 (36.3%) of the outbreaks. Health departments reported 335 (30.5%) outbreaks. For six outbreaks in which bioterrorism or intentional contamination was possible, reporting was delayed for up to 26 days. We confirmed that the most critical component for bioterrorism outbreak detection and reporting is the frontline healthcare profession and the local health departments. Bioterrorism preparedness should emphasize education and support of this frontline as well as methods to shorten the time between outbreak and reporting.
Kaiser, Robyn M.; Bales, Michael E.; Shutt, Kathleen; Patrawalla, Amee; McShan, Andre; Tappero, Jordan W.; Perkins, Bradley A.; Dannenberg, Andrew L.
To assess risk for importation of dengue virus (DENV) into Queensland, Australia, and sources of imported viruses, we sequenced the envelope region of DENV isolates from symptomatic patients with a history of travel during 2002–2010. The number of imported dengue cases greatly increased over the surveillance period, some of which were associated with domestic outbreaks. Patients reported traveling to (in order) Asia, Papua New Guinea, Pacific Island countries, and non–Asia-Pacific countries. By using phylogenetic methods, we assigned DENV isolates from returning residents and overseas visitors with viremia to a specific genotypic group. Genotypes circulating in Asia were extremely diverse. Genotyping and molecular clock analysis supported Asian origination of a strain that caused an outbreak of DENV-4 in Pacific Island countries during 2007–2009, and subsequently, in Innisfail, Australia, in 2009. Our findings indicate that Asia is a major source of DENVs that are imported into Australia, causing a risk for epidemics.
Northill, Judith A.; Pyke, Alyssa T.
Dengue fever is a widespread disease that can occur outside tropical areas. Several thousand French military personnel are exposed to this infectious risk each year and exposure is expected to rise with the creation of a professional army and the increasing number of foreign missions. As a result, dengue fever has become a major priority for the Armed Services Health Corps (ASHC). A system of epidemiological surveillance based on the active participation of all military physicians has been designed by the ASHC to collect and analyze all data relevant to cases of dengue fever involving French military personnel stationed overseas or at home. The purpose of this study is to present data compiled for the period from 1996 to 1999. Analysis of these data demonstrated that the incidence of dengue fever peaked in 1997 due to epidemic outbreaks occurring in French Polynesia and Martinique. In response to these outbreaks control measures were adapted especially in regard to vector control. This study shows that the system of surveillance implemented by the ASHC is an effective but still perfectible tool. PMID:11980396
Meynard, J B; Ollivier-Gay, L; Deparis, X; Durand, J P; Michel, R; Pages, F; Matton, T; Boutin, J P; Tolou, H; Merouze, F; Baudon, D
The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population.
Le Goff, G.; Revollo, J.; Guerra, M.; Cruz, M.; Barja Simon, Z.; Roca, Y.; Vargas Flores, J.; Herve, J.P.
The Armed Forces Health Surveillance Center, Division of Global Emerging Infections Surveillance and Response System Operations (AFHSC-GEIS) initiated a coordinated, multidisciplinary program to link data sets and information derived from eco-climatic remote sensing activities, ecologic niche modeling, arthropod vector, animal disease-host/reservoir, and human disease surveillance for febrile illnesses, into a predictive surveillance program that generates advisories and alerts on emerging infectious disease outbreaks. The program's ultimate goal is pro-active public health practice through pre-event preparedness, prevention and control, and response decision-making and prioritization. This multidisciplinary program is rooted in over 10 years experience in predictive surveillance for Rift Valley fever outbreaks in Eastern Africa. The AFHSC-GEIS Rift Valley fever project is based on the identification and use of disease-emergence critical detection points as reliable signals for increased outbreak risk. The AFHSC-GEIS predictive surveillance program has formalized the Rift Valley fever project into a structured template for extending predictive surveillance capability to other Department of Defense (DoD)-priority vector- and water-borne, and zoonotic diseases and geographic areas. These include leishmaniasis, malaria, and Crimea-Congo and other viral hemorrhagic fevers in Central Asia and Africa, dengue fever in Asia and the Americas, Japanese encephalitis (JE) and chikungunya fever in Asia, and rickettsial and other tick-borne infections in the U.S., Africa and Asia. PMID:21388561
Witt, Clara J; Richards, Allen L; Masuoka, Penny M; Foley, Desmond H; Buczak, Anna L; Musila, Lillian A; Richardson, Jason H; Colacicco-Mayhugh, Michelle G; Rueda, Leopoldo M; Klein, Terry A; Anyamba, Assaf; Small, Jennifer; Pavlin, Julie A; Fukuda, Mark M; Gaydos, Joel; Russell, Kevin L; Wilkerson, Richard C; Gibbons, Robert V; Jarman, Richard G; Myint, Khin S; Pendergast, Brian; Lewis, Sheri; Pinzon, Jorge E; Collins, Kathrine; Smith, Matthew; Pak, Edwin; Tucker, Compton; Linthicum, Kenneth; Myers, Todd; Mansour, Moustafa; Earhart, Ken; Kim, Heung Chul; Jiang, Ju; Schnabel, Dave; Clark, Jeffrey W; Sang, Rosemary C; Kioko, Elizabeth; Abuom, David C; Grieco, John P; Richards, Erin E; Tobias, Steven; Kasper, Matthew R; Montgomery, Joel M; Florin, Dave; Chretien, Jean-Paul; Philip, Trudy L
Over the last decade, the Espírito Santo State, Brazil has become an endemic Dengue fever location with annual outbreaks of\\u000a varying magnitude. It is still unclear which geographical route allowed the virus entry in the state and how it has genetically\\u000a changed since then. Therefore we have set out to study the local molecular constitution of the virus and determine
Raquel Spinassé Dettogni; Iúri Drumond Louro
Dengue fever affects over a 100 million people annually hence is one of the world's most important vector-borne diseases. The transmission area of this disease continues to expand due to many direct and indirect factors linked to urban sprawl, increased travel and global warming. Current preventative measures include mosquito control programs, yet due to the complex nature of the disease and the increased importation risk along with the lack of efficient prophylactic measures, successful disease control and elimination is not realistic in the foreseeable future. Epidemiological models attempt to predict future outbreaks using information on the risk factors of the disease. Through a systematic literature review, this paper aims at analyzing the different modeling methods and their outputs in terms of acting as an early warning system. We found that many previous studies have not sufficiently accounted for the spatio-temporal features of the disease in the modeling process. Yet with advances in technology, the ability to incorporate such information as well as the socio-environmental aspect allowed for its use as an early warning system, albeit limited geographically to a local scale. PMID:22629476
Racloz, Vanessa; Ramsey, Rebecca; Tong, Shilu; Hu, Wenbiao
Dengue fever affects over a 100 million people annually hence is one of the world's most important vector-borne diseases. The transmission area of this disease continues to expand due to many direct and indirect factors linked to urban sprawl, increased travel and global warming. Current preventative measures include mosquito control programs, yet due to the complex nature of the disease and the increased importation risk along with the lack of efficient prophylactic measures, successful disease control and elimination is not realistic in the foreseeable future. Epidemiological models attempt to predict future outbreaks using information on the risk factors of the disease. Through a systematic literature review, this paper aims at analyzing the different modeling methods and their outputs in terms of acting as an early warning system. We found that many previous studies have not sufficiently accounted for the spatio-temporal features of the disease in the modeling process. Yet with advances in technology, the ability to incorporate such information as well as the socio-environmental aspect allowed for its use as an early warning system, albeit limited geographically to a local scale.
Racloz, Vanessa; Ramsey, Rebecca; Tong, Shilu; Hu, Wenbiao
Although the introduction of the measles vaccine in the United States in 1963 has led to a marked decrease in the incidence of measles (rubeola), this childhood exanthem has not been eliminated. Since 1983, increases in incidence have been observed. Outbreaks have occurred among previously immunized school and college-age students and unimmunized preschool children, infants, and babies. This article reports a measles outbreak at a state university in Texas and proposes a plan to develop immunity against measles to prevent future outbreaks at college and university campuses. PMID:1574783
Zoretic, J A
Dengue fever (DF) is endemic in tropical and subtropical zones and the prevalence is increasing across South-east Asia, Africa, the Western Pacific and the Americas. In recent years, the spread of unplanned urbanisation, with associated substandard housing, overcrowding and deterioration in water, sewage and waste management systems, has created ideal conditions for increased transmission of the dengue virus in tropical urban centres. While dengue infection has traditionally been considered a paediatric disease, the age distribution of dengue has been rising and more cases have been observed in adolescents and adults. Furthermore, the development of tourism in the tropics has led to an increase in the number of tourists who become infected, most of whom are adults. Symptoms and risk factors for dengue haemorrhagic fever (DHF) and severe dengue differ between children and adults, with co-morbidities and incidence in more elderly patients associated with greater risk of mortality. Treatment options for DF and DHF in adults, as for children, centre round fluid replacement (either orally or intravenously, depending on severity) and antipyretics. Further data are needed on the optimal treatment of adult patients.
West Nile virus (WN), an agent of significant human and veterinary disease, is endemic in the Old World and rapidly spreading throughout the Americas. Vaccines are needed to halt the geographic expansion of this virus and prevent disease where it is established. However, to preclude introduction of a vaccine virus into the environment, a live attenuated WN vaccine should have low potential for transmission by mosquitoes. A chimeric WN vaccine candidate was previously generated by replacing the membrane and envelope structural protein genes of recombinant dengue type 4 virus (rDEN4) with those of WN; a derivative of this virus, WN/DEN4-3'delta30, contains a 30-nucleotide deletion in the 3' untranslated region. To assess the potential for transmission by mosquitoes of these vaccine candidates, the ability of each chimeric virus to infect the mosquito midgut, disseminate to the head, and pass into the saliva was compared to that of their wild-type parental WN and DEN4 viruses in three vector species. The WN/DEN4 chimeric viruses were significantly attenuated in both Culex tarsalis, a vector able to transmit WN but not dengue, and in Ae. aegypti, a vector able to transmit dengue but not WN. However, the chimeric viruses were as infectious as either wild-type virus for Ae. albopictus, a vector able to transmit both dengue and WN. These results indicate that chimerization caused a contraction in vector host range rather than universal attenuation for mosquitoes per se. This restriction in potential vectors renders it less likely that WN/DEN4 and WN/DEN4-3'delta30 would be transmitted from vaccinees to mosquitoes. PMID:15815144
Hanley, Kathryn A; Goddard, Laura B; Gilmore, Lara E; Scott, Thomas W; Speicher, James; Murphy, Brian R; Pletnev, Alexander G
Text Version... as early as day of fever onset; Present in both ... Evaluation of Dengue Diagnostic Kits. ... sites established: Asia: Cambodia, Malaysia, Thailand, Vietnam; ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials
Dengue viruses are the most important arboviruses causing human disease. Expansion of the disease in recent decades to include more geographical areas of the world, an appreciation of the disease burden and market potentials have spurred a flurry of activity in the development of vaccines to combat dengue viruses. Recent progress in this area and some of the obstacles associated with this development are discussed. PMID:19535912
Raviprakash, Kanakatte; Defang, Gabriel; Burgess, Timothy; Porter, Kevin
To understand circumstances of tuberculosis transmission that strain public health resources, we systematically reviewed Centers for Disease Control and Prevention (CDC) staff reports of US outbreaks in which CDC participated during 2002–2008 that involved >3 culture-confirmed tuberculosis cases linked by genotype and epidemiology. Twenty-seven outbreaks, representing 398 patients, were reviewed. Twenty-four of the 27 outbreaks involved primarily US-born patients; substance abuse was another predominant feature of outbreaks. Prolonged infectiousness because of provider- and patient-related factors was common. In 17 outbreaks, a drug house was a notable contributing factor. The most frequently documented intervention to control the outbreak was prioritizing contacts according to risk for infection and disease progression to ensure that the highest risk contacts were completely evaluated. US-born persons with reported substance abuse most strongly characterized the tuberculosis outbreaks in this review. Substance abuse remains one of the greatest challenges to controlling tuberculosis transmission in the United States.
Oeltmann, John E.; Ijaz, Kashef; Haddad, Maryam B.
We examined outbreak investigations conducted around the world from 1988 to 1999 by the Centers for Disease Control and Prevention's Epidemic Intelligence Service. In 44 (4.0%) of 1,099 investigations, identified causative agents had bioterrorism potential. In six investigations, intentional use of infectious agents was considered. Healthcare providers reported 270 (24.6%) outbreaks and infection control practitioners reported 129 (11.7%); together they reported 399 (36.3%) of the outbreaks. Health departments reported 335 (30.5%) outbreaks. For six outbreaks in which bioterrorism or intentional contamination was possible, reporting was delayed for up to 26 days. We confirmed that the most critical component for bioterrorism outbreak detection and reporting is the frontline healthcare profession and the local health departments. Bioterrorism preparedness should emphasize education and support of this frontline as well as methods to shorten the time between outbreak and reporting. PMID:12737732
Ashford, David A; Kaiser, Robyn M; Bales, Michael E; Shutt, Kathleen; Patrawalla, Amee; McShan, Andre; Tappero, Jordan W; Perkins, Bradley A; Dannenberg, Andrew L
Passive immunization with monoclonal antibodies from humans or nonhuman primates represents an attractive alternative to vaccines for prevention of illness caused by dengue viruses (DENV) and other flaviviruses, including the West Nile virus. In a previous study, repertoire cloning to recover Fab fragments from bone marrow mRNA of chimpanzees infected with all four DENV serotypes (dengue virus serotype 1 (DENV-1)
Ana P. Goncalvez; Ruhe Men; Claire Wernly; Robert H. Purcell; Ching-Juh Lai
Dengue hemorrhagic fever (DHF) causing by dengue viral infection is endemic in Thailand and Southeast Asian countries where thalassemias are prevalent. Thalassemic patients are also at risk to acquire dengue viral infections and to develop DHF. However, they can have different clinical manifestations and complications as well as more severity than general population requiring special awareness for proper diagnosis and
The evolution of dengue viruses has had a major impact on their virulence for humans and on the epidemiology of dengue disease around the world. Although antigenic and genetic differences in virus strains had become evident, it is mainly due to the lack of animal models of disease that has made it difficult to detect differences in virulence of dengue
Dengue fever is a public health problem of growing importance. Today, at least one-third of the world' population lives in areas of regular or episodic dengue transmission. The recognition that individuals can experience more than one dengue infection and...
W. H. Bancroft K. H. Eckels W. E. Brandt
The pathophysiological basis of severe dengue disease (i.e., dengue hemorrhagic fever [DHF]), appears to be multifactorial, involving complex interactions among viral factors, host genetics, and the immunologic background of the host, principally prior exposure to dengue virus. Analysis of these processes has been limited to observational studies of naturally infected humans because there have not been useful animal models of
Alan L. Rothman
This review provides details on the role of Geographical Information Systems (GIS) in current dengue surveillance systems and focuses on the application of open access GIS technology to emphasize its importance in developing countries, where the dengue burden is greatest. It also advocates for increased international collaboration in transboundary disease surveillance to confront the emerging global challenge of dengue.
Duncombe, Jennifer; Clements, Archie; Hu, Wenbiao; Weinstein, Philip; Ritchie, Scott; Espino, Fe Esperanza
Independent outbreaks of dengue virus (DENV) infection and sporadic cases of chikungunya virus (CHIKV) have been recorded in the metropolitan city of Delhi on several occasions in the past. However, during a recent 2010 arboviral outbreak in Delhi many cases turned negative for DENV. This prompted us to use duplex reverse transcriptase-polymerase chain reaction (D-RT-PCR) to establish the aetiology of dengue/chikungunya through sequencing of CprM and E1 genes of dengue and chikungunya viruses. Interestingly, for the first time, both DENV and CHIKV co-circulated simultaneously and in equally dominant proportion during the post-monsoon period of 2010. DENV-1 genotype III and the East Central South African genotype of CHIKV were associated with post-monsoon spread of these viruses. PMID:21906409
Singh, P; Mittal, V; Rizvi, M M A; Chhabra, M; Sharma, P; Rawat, D S; Bhattacharya, D; Chauhan, L S; Rai, A
During August 2009-October 2010, a multidisciplinary team investigated 14 outbreaks of animal and human anthrax in Bangladesh to identify the etiology, pathway of transmission, and social, behavioral, and cultural factors that led to these outbreaks. The team identified 140 animal cases of anthrax and 273 human cases of cutaneous anthrax. Ninety one percent of persons in whom cutaneous anthrax developed had history of butchering sick animals, handling raw meat, contact with animal skin, or were present at slaughtering sites. Each year, Bacillus anthracis of identical genotypes were isolated from animal and human cases. Inadequate livestock vaccination coverage, lack of awareness of the risk of anthrax transmission from animal to humans, social norms and poverty contributed to these outbreaks. Addressing these challenges and adopting a joint animal and human health approach could contribute to detecting and preventing such outbreaks in the future. PMID:22492157
Chakraborty, Apurba; Khan, Salah Uddin; Hasnat, Mohammed Abul; Parveen, Shahana; Islam, M Saiful; Mikolon, Andrea; Chakraborty, Ranjit Kumar; Ahmed, Be-Nazir; Ara, Khorsed; Haider, Najmul; Zaki, Sherif R; Hoffmaster, Alex R; Rahman, Mahmudur; Luby, Stephen P; Hossain, M Jahangir
During August 2009–October 2010, a multidisciplinary team investigated 14 outbreaks of animal and human anthrax in Bangladesh to identify the etiology, pathway of transmission, and social, behavioral, and cultural factors that led to these outbreaks. The team identified 140 animal cases of anthrax and 273 human cases of cutaneous anthrax. Ninety one percent of persons in whom cutaneous anthrax developed had history of butchering sick animals, handling raw meat, contact with animal skin, or were present at slaughtering sites. Each year, Bacillus anthracis of identical genotypes were isolated from animal and human cases. Inadequate livestock vaccination coverage, lack of awareness of the risk of anthrax transmission from animal to humans, social norms and poverty contributed to these outbreaks. Addressing these challenges and adopting a joint animal and human health approach could contribute to detecting and preventing such outbreaks in the future.
Chakraborty, Apurba; Khan, Salah Uddin; Hasnat, Mohammed Abul; Parveen, Shahana; Islam, M. Saiful; Mikolon, Andrea; Chakraborty, Ranjit Kumar; Ahmed, Be-Nazir; Ara, Khorsed; Haider, Najmul; Zaki, Sherif R.; Hoffmaster, Alex R.; Rahman, Mahmudur; Luby, Stephen P.; Hossain, M. Jahangir
Dengue fever is a mosquito-borne viral disease prevalent mainly in tropical countries. As the clinical manifestations of dengue are not very unique, laboratory diagnosis is crucial in identifying cases of dengue infection. Detection of dengue infection based on the identification of antidengue antibodies has emerged as a practical and reliable means of diagnosing dengue fever. We recently developed a customized
Ravulapalli AnandaRao; Sathyamangalam Swaminathan; Sirimali Fernando; Asha M. Jana; Navin Khanna
Dengue virus infections are an emerging global threat. Severe dengue infection is manifested as dengue hemorrhagic fever and dengue shock syndrome, both of which can be fatal complications. Factors predisposing to complicated disease and pathogenesis of severe infections are discussed. Using immunohistochemistry, immunofluorescence, flow cytometry, and ELISA techniques, we studied the cellular targets of dengue virus infection, at both the
Mary Marovich; Geraldine Grouard-Vogel; Mark Louder; Michael Eller; Wellington Sun; Shuenn-Ju Wu; Ravithat Putvatana; Gerald Murphy; Boonrat Tassaneetrithep; Timothy Burgess; Deborah Birx; Curtis Hayes; Sarah Schlesinger-Frankel; John Mascola; M. Marovitch
Although the dengue iceberg phenomenon is well known, there is a paucity of data on inapparent dengue. Results from a seroepidemiological study conducted during a dengue epidemic in 2007 in Singapore showed a seroprevalence of 65.9% and an inapparent dengue rate of 78%. Older adults (> 45 years old) had significantly higher rates of inapparent dengue infections (P < 0.05).
Yap, Grace; Li, Chenny; Mutalib, Adeliza; Lai, Yee-Ling; Ng, Lee-Ching
Background Dengue remains an important cause of morbidity in Laos. Good knowledge, attitudes and practices (KAP) among the public regarding dengue prevention are required for the success of disease control. Very little is known about dengue KAP among the Lao general population. Methods This was a KAP household survey on dengue conducted in a peri-urban Pak-Ngum district of Vientiane capital, Laos. A two-stage cluster sampling method was used to select a sample of participants to represent the general community. Participants from 231 households were surveyed using an interviewer-administered questionnaire. Results Although 97% of the participants heard of dengue, there was a lack of depth of knowledge on dengue: 33% of them did not know that malaria and dengue were different diseases, 32% incorrectly believed that Aedes mosquito transmits malaria, 36% could not correctly report that Aedes mosquitoes bite most frequently at sunrise and sunset; and?10% of them recognized that indoor water containers could be Aedes mosquito breeding sites. Attitude levels were moderately good with a high proportion (96%) of participants recognizing that dengue was a severe yet preventable disease. Self reported prevention methods were quite high yet observation of the participants’ yards showed use of prevention methods to be only moderate. The majority (93%) of the interviewees did not believe that they had enough information on dengue. There was an association between good knowledge and better practices, but good knowledge was associated with worse attitudes. Conclusions There is a lack of depth of knowledge regarding dengue in Pak-Ngum community and observation methods revealed that more needs to be done by community members themselves to prevent the spread of Aedes mosquitoes.
Introduction Dengue virus (DENV) affects over half the world’s population in 112 countries, and dengue fever (DF) is the second largest arthropod borne infectious global hazard after malaria with complications like Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS), accounting for significant morbidity and mortality world-over. Pakistan is significantly affected with DENV infection and to-date no study identifying risk factors associated with development of severe complications of DF has been done. Methods 997 confirmed cases of DF were collected from a tertiary care hospital in Lahore, Pakistan and their clinical and biochemical data were collected. Univariate, multivariate and logistics regression analysis was performed to identify risk factors associated with development of DHF and DSS. Results Bleeding OR 70.7 (CI 38.4–129.9), deranged liver function test OR 1.9 (CI 0.97–0.99), presence of urinary red blood cells OR 1.4 (95%CI 0.179–0.900) and presence of urinary protein OR 1.1 (95%CI 0.191–0.974) were related to development of DHF and DSS. Discussion Severe Dengue, like DHF and DSS can be predicted by the presence of clinical and biochemical factors like signs of bleeding, deranged liver function test, presence of urinary red blood cells and urinary protein; so that the patients at high risk for complication be identified early and started on treatment timely. Conclusion Predictors of severe dengue are identified in this study but further large scale multi-centered studies are needed for better interpretation.
Khan, Muhammad Imran Hasan; Anwar, Eram; Agha, Adnan; Hassanien, Noha Saleh Mohamed; Ullah, Ehsan; Syed, Imran Ali; Raja, Arsalan
Dengue is a vector-borne viral infection of global importance. Several pathogenetic mechanisms such as immune enhancement and selection pressure have been proposed and febrile, critical and recovery phases have been identified. A new classification proposed by WHO has recently been introduced where definitions have been changed to 'probable dengue', 'dengue with warning signs' and 'severe dengue'. The majority of dengue viral infections are self-limiting, but complications have high morbidity and mortality. The diagnosis of dengue viral infection is essentially clinical, although confirmation requires laboratory tests including serology, NS1 antigen detection, PCR and viral cultures. There are no specific anti-dengue drugs and treatment is basically supportive and consists of early recognition of complications and appropriate fluid therapy. A number of candidate vaccines are under development. PMID:22806236
Balasubramanian, S; Ramachandran, Bala; Amperayani, Sumanth
An improved understanding of heterogeneities in dengue virus transmission might provide insights into biological and ecologic drivers and facilitate predictions of the magnitude, timing, and location of future dengue epidemics. To investigate dengue dynamics in urban Ho Chi Minh City and neighboring rural provinces in Vietnam, we analyzed a 10-year monthly time series of dengue surveillance data from southern Vietnam. The per capita incidence of dengue was lower in Ho Chi Minh City than in most rural provinces; annual epidemics occurred 1-3 months later in Ho Chi Minh City than elsewhere. The timing and the magnitude of annual epidemics were significantly more correlated in nearby districts than in remote districts, suggesting that local biological and ecologic drivers operate at a scale of 50-100 km. Dengue incidence during the dry season accounted for 63% of variability in epidemic magnitude. These findings can aid the targeting of vector-control interventions and the planning for dengue vaccine implementation. PMID:23735713
Cuong, Hoang Quoc; Vu, Nguyen Thanh; Cazelles, Bernard; Boni, Maciej F; Thai, Khoa T D; Rabaa, Maia A; Quang, Luong Chan; Simmons, Cameron P; Huu, Tran Ngoc; Anders, Katherine L
Dengue virus is the most significant virus transmitted by arthropods worldwide and may cause a potentially fatal systemic disease named dengue hemorrhagic fever. In this work, dengue virus serotype 4 was detected in the tissues of one fatal dengue hemorrhagic fever case using electron immunomicroscopy and molecular methods. This is the first report of dengue virus polypeptides findings by electron immunomicroscopy in human samples. In addition, not-previously-documented virus-like particles visualized in spleen, hepatic, brain, and pulmonary tissues from a dengue case are discussed. PMID:22527878
Limonta, D; Falcón, V; Torres, G; Capó, V; Menéndez, I; Rosario, D; Castellanos, Y; Alvarez, M; Rodríguez-Roche, R; de la Rosa, M C; Pavón, A; López, L; González, K; Guillén, G; Diaz, J; Guzmán, M G
OBJECTIVES. Mumps is a vaccine-preventable disease that may cause outbreaks. In July 2005, an outbreak of mumps occurred during a children's summer camp in upstate New York. An investigation was initiated to describe the cases and evaluate vaccine effectiveness. METHODS. A retrospective cohort study was conducted among 541 children from the United States and abroad who attended a 1- or
Joshua K. Schaffzin; Lynn Pollock; Cynthia Schulte; Kyle Henry; Gustavo Dayan; Perry Smith
Background Recognized outbreaks of Legionnaires' disease (LD) are rare; when they occur, they provide opportunities to understand the epidemiology of the illness and improve prevention strategies. We investigated a population-based outbreak. Methods After the confirmation of LD in October 1996 in five people in neighbouring towns in southwest Virginia, active surveillance for additional cases was undertaken. A case-control study was
Denise H Benkel; Emily M McClure; Diane Woolard; John V Rullan; Suzanne R Jenkins; Jody H Hershey; Robert F Benson; Janet M Pruckler; Ellen W Brown; Margarette S Kolczak; Robert L Hackler; Betty S Rousec; Robert F Breimanb
Objectives: To investigate patterns of behaviours and attitudes related to SARS prevention in the Hong Kong cross border traveller population.Settings: A survey was carried out at the Hong Kong-China cross border checkpoint in the middle of the epidemic.Participants: A total of 839 Hong Kong adult residents returning to Hong Kong from mainland China were surveyed.Main outcome measures: Practice of preventive
Joseph T F Lau; Xilin Yang; H Y Tsui; Ellie Pang
Dengue and dengue hemorrhagic fever in the Americas have been on the rise throughout the 1990s, with the highest number -over one million cases- reported in 2002. This paper analyzed the situation of dengue in the region and discussed the determining factors that account for the rise of the disease, making emphasis on socioeconomic factors, such as poverty, inequality, migrations and the lack of access to basic services, which are the most influential in perpetuating this disease in most countries. Considering that a safe and accessible vaccine is now unavailable, basic principles of vector control combined with political willingness, inter-sectoral involvement, active community participation and the tightening of health legislation were also examined as the only viable solution at present. PMID:23427454
Kouri, Gustavo; Pelegrino, José L; Munster, Blanca María; Guzmán, María G
Background Dengue vaccines are now in late-stage development, and evaluation and robust estimates of dengue disease burden are needed to facilitate further development and introduction. In Cambodia, the national dengue case-definition only allows reporting of children less than 16 years of age, and little is known about dengue burden in rural areas and among older persons. To estimate the true burden of dengue in the largest province of Cambodia, Kampong Cham, we conducted community-based active dengue fever surveillance among the 0-to-19–year age group in rural villages and urban areas during 2006–2008. Methods and Findings Active surveillance for febrile illness was conducted in 32 villages and 10 urban areas by mothers trained to use digital thermometers combined with weekly home visits to identify persons with fever. An investigation team visited families with febrile persons to obtain informed consent for participation in the follow-up study, which included collection of personal data and blood specimens. Dengue-related febrile illness was defined using molecular and serological testing of paired acute and convalescent blood samples. Over the three years of surveillance, 6,121 fever episodes were identified with 736 laboratory-confirmed dengue virus (DENV) infections for incidences of 13.4–57.8/1,000 person-seasons. Average incidence was highest among children less than 7 years of age (41.1/1,000 person-seasons) and lowest among the 16-to-19–year age group (11.3/1,000 person-seasons). The distribution of dengue was highly focal, with incidence rates in villages and urban areas ranging from 1.5–211.5/1,000 person-seasons (median 36.5). During a DENV-3 outbreak in 2007, rural areas were affected more than urban areas (incidence 71 vs. 17/1,000 person-seasons, p<0.001). Conclusion The large-scale active surveillance study for dengue fever in Cambodia found a higher disease incidence than reported to the national surveillance system, particularly in preschool children and that disease incidence was high in both rural and urban areas. It also confirmed the previously observed focal nature of dengue virus transmission.
Vong, Sirenda; Khieu, Virak; Glass, Olivier; Ly, Sowath; Duong, Veasna; Huy, Rekol; Ngan, Chantha; Wichmann, Ole; Letson, G. William; Margolis, Harold S.; Buchy, Philippe
Background Dengue infection ranks as one of the most significant viral diseases of the globe. Currently, there is no specific vaccine or antiviral therapy for prevention or treatment. Monocytes/macrophages are the principal target cells for dengue virus and are responsible for disseminating the virus after its transmission. Dengue virus enters target cells via receptor-mediated endocytosis after the viral envelope protein E attaches to the cell surface receptor. This study aimed to investigate the effect of silencing the CD-14 associated molecule and clathrin-mediated endocytosis using siRNA on dengue virus entry into monocytes. Methodology/Principal Findings Gene expression analysis showed a significant down-regulation of the target genes (82.7%, 84.9 and 76.3% for CD-14 associated molecule, CLTC and DNM2 respectively) in transfected monocytes. The effect of silencing of target genes on dengue virus entry into monocytes was investigated by infecting silenced and non-silenced monocytes with DENV-2. Results showed a significant reduction of infected cells (85.2%), intracellular viral RNA load (73.0%), and extracellular viral RNA load (63.0%) in silenced monocytes as compared to non-silenced monocytes. Conclusions/Significance Silencing the cell surface receptor and clathrin mediated endocytosis using RNA interference resulted in inhibition of the dengue virus entry and subsequently multiplication of the virus in the monocytes. This might serve as a novel promising therapeutic target to attenuate dengue infection and thus reduce transmission as well as progression to severe dengue hemorrhagic fever.
Alhoot, Mohammed Abdelfatah; Wang, Seok Mui; Sekaran, Shamala Devi
The outbreak of chikungunya fever that surfaced in India during late 2005 has affected more than 1.56 million people, spread to more than 17 states/union territories, and is still ongoing. Many of these areas are dengue- and leptospirosis-endemic settings. We carried out a cross-sectional survey in one such chikungunya-affected location in Dakshina Kannada District of Karnataka State to estimate the magnitude of the epidemic and the proportion of chikungunya virus (CHIKV) infections that remained clinically inapparent. The seropositivity for CHIKV infection was 62.2%, and the attack rate of confirmed CHIK fever was 58.3%. The proportion of inapparent CHIKV infection was 6.3%. The increasing trend in the seropositivity and attack rate of CHIKV infection with age group was statistically significant. The present study is an indicator of the magnitude of the ongoing outbreak of CHIKV infection in India that started during 2005-2006. PMID:20889860
Manimunda, Sathya P; Sugunan, Attayur P; Rai, Subhodh K; Vijayachari, Paluru; Shriram, Ananganallur N; Sharma, Sameer; Muruganandam, Nagarajan; Chaitanya, Itta K; Guruprasad, Dev R; Sudeep, Anakkathil B
The outbreak of chikungunya fever that surfaced in India during late 2005 has affected more than 1.56 million people, spread to more than 17 states/union territories, and is still ongoing. Many of these areas are dengue- and leptospirosis-endemic settings. We carried out a cross-sectional survey in one such chikungunya-affected location in Dakshina Kannada District of Karnataka State to estimate the magnitude of the epidemic and the proportion of chikungunya virus (CHIKV) infections that remained clinically inapparent. The seropositivity for CHIKV infection was 62.2%, and the attack rate of confirmed CHIK fever was 58.3%. The proportion of inapparent CHIKV infection was 6.3%. The increasing trend in the seropositivity and attack rate of CHIKV infection with age group was statistically significant. The present study is an indicator of the magnitude of the ongoing outbreak of CHIKV infection in India that started during 2005–2006.
Manimunda, Sathya P.; Sugunan, Attayur P.; Rai, Subhodh K.; Vijayachari, Paluru; Shriram, Ananganallur N.; Sharma, Sameer; Muruganandam, Nagarajan; Chaitanya, Itta K.; Guruprasad, Dev R.; Sudeep, Anakkathil B.
Factors known to trigger the emergence or re-emergence of infectious diseases include globalisation, population growth, migration, international trade, urbanisation, forest destruction, climate change, loss of biodiversity, poverty, famine and war. Epidemics not only lead to disastrous loss of human life but may also have catastrophic economic, political and social consequences. Outbreaks may rapidly jeopardize industry, trade or tourism in countries that are unprepared. Dengue is currently spreading throughout the tropics, while another arbovirus, chikungunya, infected 30 to 75% of the population in some parts of the Indian Ocean region between 2005 and 2006. Chikungunya is now spreading through India, where more than a million people have so far been infected. This viral disease can cause lasting disability, and the first deaths were recently reported in La Réunion and Mayotte. All countries are at risk from emerging or re-emerging diseases, but the consequences are far worse in poor countries. Microbial pathogens and wild mammals, birds and arthropods do not respect man-made borders. There is still time to act against this threat of emerging and re-emerging infectious diseases, through prevention, anticipation, monitoring and research. PMID:17645111
In the past 10 years, an increasing number of outbreaks of enteric disease associated with animals in public settings, such as fairs and petting zoos, have been reported. Fifty-five of these outbreaks that occurred in the United States during 1991- 2005 are reviewed in this article. Lessons learned from these outbreaks and recommendations for prevention are also discussed. Physicians should
Frederick J. Angulo; Nicole Steinmuller; Linda Demma; Jeff B. Bender; Millicent Eidson
The dengue viruses (DENV) are endemic in the tropical and sub-tropical countries and cause the most common arthropod-borne viral disease in humans. Travelers visiting endemic areas may both acquire and spread DENV infections, and this is the reason why prevention of mosquito bites is of crucial importance. Dengue fever (DF) has become the most common cause for tropical fever in Swedish tourists. Swedish data from 1995 to 2010 show that the number of DF cases has increased since the beginning of 2000; partly due to improved diagnostics based on IgM detection, and partly due to an increase in the number of tourists traveling to, and between, endemic areas. Young adults aged 20-29 are mostly affected, and epidemiological data indicate increased incidence rates from 2008 onwards. Our data pose a call for attention when traveling to DENV endemic areas as well as an increased awareness among physicians when treating returning travelers. PMID:22957112
Tuiskunen, Anne; Hjertqvist, Marika; Vene, Sirkka; Lundkvist, Ake
BACKGROUND: The ability to detect disease outbreaks in their early stages is a key component of efficient disease control and prevention. With the increased availability of electronic health-care data and spatio-temporal analysis techniques, there is great potential to develop algorithms to enable more effective disease surveillance. However, to ensure that the algorithms are effective they need to be evaluated. The
Rochelle E Watkins; Serryn Eagleson; Sam Beckett; Graeme Garner; Bert Veenendaal; Graeme Wright; Aileen J Plant
Population outbreaks in tundra rodents have intrigued scientists for a century as a result of their spectacular appearances and their general lessons in ecology. One outstanding question that has led to competing hypotheses is why sympatric lemmings and voles differ in regularity and shape of their outbreaks. Lemming outbreaks may be lost for decades while vole populations maintain regular population cycles. Moreover, when lemming populations eventually irrupt, they do so more steeply than the vole populations. Norwegian lemmings exhibited a large-scale outbreak synchronously with gray-sided voles in Finnmark, northern Fennoscandia, during 2006 to 2007 for the first time in two decades. Analyses of spatial variability of this outbreak across altitudinal gradients allowed us to identify determinants of the contrasting lemming and vole dynamics. The steeper lemming outbreak trajectories were caused by breeding and population growth during winter, when nonbreeding vole populations consistently declined. The differently shaped lemming and vole outbreaks appear to result from a particular demographic tactic of lemmings that evolved as an adaptation to the long and cold Arctic-Alpine winters. The lemming outbreak amplitude increased with altitude and vole density, indicating that lemming outbreaks are jointly facilitated by low temperatures and apparent mutualism with voles mediated by shared predators. High sensitivity to variation in climate and predation is likely to be the reasons why lemmings have more erratic population dynamics than sympatric voles. The combination of continued climatic warming and dampened vole cycles is expected to further decrease the frequency, amplitude, and geographic range of lemming outbreaks in tundra ecosystems. PMID:21245340
Ims, Rolf A; Yoccoz, Nigel G; Killengreen, Siw T
Population outbreaks in tundra rodents have intrigued scientists for a century as a result of their spectacular appearances and their general lessons in ecology. One outstanding question that has led to competing hypotheses is why sympatric lemmings and voles differ in regularity and shape of their outbreaks. Lemming outbreaks may be lost for decades while vole populations maintain regular population cycles. Moreover, when lemming populations eventually irrupt, they do so more steeply than the vole populations. Norwegian lemmings exhibited a large-scale outbreak synchronously with gray-sided voles in Finnmark, northern Fennoscandia, during 2006 to 2007 for the first time in two decades. Analyses of spatial variability of this outbreak across altitudinal gradients allowed us to identify determinants of the contrasting lemming and vole dynamics. The steeper lemming outbreak trajectories were caused by breeding and population growth during winter, when nonbreeding vole populations consistently declined. The differently shaped lemming and vole outbreaks appear to result from a particular demographic tactic of lemmings that evolved as an adaptation to the long and cold Arctic–Alpine winters. The lemming outbreak amplitude increased with altitude and vole density, indicating that lemming outbreaks are jointly facilitated by low temperatures and apparent mutualism with voles mediated by shared predators. High sensitivity to variation in climate and predation is likely to be the reasons why lemmings have more erratic population dynamics than sympatric voles. The combination of continued climatic warming and dampened vole cycles is expected to further decrease the frequency, amplitude, and geographic range of lemming outbreaks in tundra ecosystems.
Ims, Rolf A.; Yoccoz, Nigel G.; Killengreen, Siw T.
Dengue is a major public health problem in tropical and subtropical regions; however, under-reporting of cases to national surveillance systems hinders accurate knowledge of disease burden and costs. Laboratory-confirmed dengue cases identified through the Nicaraguan Pediatric Dengue Cohort Study (PDCS) were compared to those reported from other health facilities in Managua to the National Epidemiologic Surveillance (NES) program of the Nicaraguan Ministry of Health. Compared to reporting among similar pediatric populations in Managua, the PDCS identified 14 to 28 (average 21.3) times more dengue cases each year per 100,000 persons than were reported to the NES. Applying these annual expansion factors to national-level data, we estimate that the incidence of confirmed pediatric dengue throughout Nicaragua ranged from 300 to 1000 cases per 100,000 persons. We have estimated a much higher incidence of dengue than reported by the Ministry of Health. A country-specific expansion factor for dengue that allows for a more accurate estimate of incidence may aid governments and other institutions calculating disease burden, costs, resource needs for prevention and treatment, and the economic benefits of drug and vaccine development.
Standish, Katherine; Kuan, Guillermina; Aviles, William; Balmaseda, Angel; Harris, Eva
Outbreaks of dengue hemorrhagic fever have coincided with the introduction of the Southeast (SE) Asian genotype of dengue type 2 virus in the Western Hemisphere. This introduced genotype appears to be rapidly displacing the indigenous, American genotype of dengue 2 virus throughout the region. These field observations raise the possibility that the SE Asian genotype of dengue 2 is better adapted for vector transmission than its American counterpart. To evaluate this hypothesis, we compared the ability of viral strains of the SE Asian and American genotypes to infect, replicate, and disseminate within vector mosquitoes (Aedes aegypti). Viral strains of the SE Asian genotype tended to infect and disseminate more efficiently in mosquitoes than did variants of the American genotype. These differences, however, were observed solely in field-derived mosquitoes, whereas viral infection rates were virtually identical in the laboratory-adapted Rockefeller colony of Ae. aegypti. Our findings could provide a physiological basis for the contrasting patterns of dengue virus genotype transmission and spread. Such an understanding of functional differences between viral strains and genotypes may ultimately improve surveillance and intervention strategies.
ARMSTRONG, PHILIP M.; RICO-HESSE, REBECA
Dengue represents an important public health issue in many tropical areas, leading to high morbidity and the employment of substantial health resources. Even though the number of fatalities related to dengue is unknown, several reports warn about the potential occurrence of severe infections and even death. The clinical spectrum of dengue is highly variable, ranging from a mild flu-like syndrome to severe disease, with shock and hemorrhage. The occurrence of bacterial superinfection, or coinfection, in patients with dengue has been noted by some authors, but the available information comes from anecdotic reports. In this study, we show the clinical and anatomopathological data of a patient infected with dengue, who subsequently died of acute multi-organic failure related to Staphylococcus aureus infection. The autopsy revealed a severe disseminated staphylococcal disease and confirmed dengue infection.
Araujo, Stanley Almeida; Moreira, Daniel Ribeiro; Veloso, Juliana Marcia Ribeiro; Silva, Jenaine Oliveira; Barros, Vera Lucia Souza Reis; Nobre, Vandack
Dengue is a systemic viral infection transmitted between humans by Aedes mosquitoes1. For some patients dengue is a life-threatening illness2. There are currently no licensed vaccines or specific therapeutics, and substantial vector control efforts have not stopped its rapid emergence and global spread3. The contemporary worldwide distribution of the risk of dengue virus infection4 and its public health burden are poorly known2,5. Here we undertake an exhaustive assembly of known records of dengue occurrence worldwide, and use a formal modelling framework to map the global distribution of dengue risk. We then pair the resulting risk map with detailed longitudinal information from dengue cohort studies and population surfaces to infer the public health burden of dengue in 2010. We predict dengue to be ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and the degree of urbanisation. Using cartographic approaches, we estimate there to be 390 million (95 percent credible interval 284-528) dengue infections per year, of which 96 million (67-136) manifest apparently (any level of clinical or sub-clinical severity). This infection total is more than three times the dengue burden estimate of the World Health Organization2. Stratification of our estimates by country allows comparison with national dengue reporting, after taking into account the probability of an apparent infection being formally reported. The most notable differences are discussed. These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue. We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help guide improvements in disease control strategies using vaccine, drug and vector control methods and in their economic evaluation. [285
Bhatt, Samir; Gething, Peter W.; Brady, Oliver J.; Messina, Jane P.; Farlow, Andrew W.; Moyes, Catherine L.; Drake, John M.; Brownstein, John S.; Hoen, Anne G.; Sankoh, Osman; Myers, Monica F.; George, Dylan B.; Jaenisch, Thomas; Wint, G.R. William; Simmons, Cameron P.; Scott, Thomas W.; Farrar, Jeremy J.; Hay, Simon I.
Successive epidemics of dengue have been occurring in Brazil since 1986 and almost three million cases of dengue fever (DF) and 2,229 cases of dengue haemorrhagic fever (DHF) had already been recorded till 15 September 2002. The introduction of the three serotypes in circulation (DEN-1, DEN-2 and DEN- 3) has always started in Rio de Janeiro. Approximately 47,370 and 89,394
Maria da Glória Teixeira; Maria da Conceição; Nascimento Costa; Maurício Lima Barreto
Dengue is a systemic viral infection transmitted between humans by Aedes mosquitoes. For some patients, dengue is a life-threatening illness. There are currently no licensed vaccines or specific therapeutics, and substantial vector control efforts have not stopped its rapid emergence and global spread. The contemporary worldwide distribution of the risk of dengue virus infection and its public health burden are poorly known. Here we undertake an exhaustive assembly of known records of dengue occurrence worldwide, and use a formal modelling framework to map the global distribution of dengue risk. We then pair the resulting risk map with detailed longitudinal information from dengue cohort studies and population surfaces to infer the public health burden of dengue in 2010. We predict dengue to be ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and the degree of urbanization. Using cartographic approaches, we estimate there to be 390 million (95% credible interval 284-528) dengue infections per year, of which 96 million (67-136) manifest apparently (any level of disease severity). This infection total is more than three times the dengue burden estimate of the World Health Organization. Stratification of our estimates by country allows comparison with national dengue reporting, after taking into account the probability of an apparent infection being formally reported. The most notable differences are discussed. These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue. We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help to guide improvements in disease control strategies using vaccine, drug and vector control methods, and in their economic evaluation. PMID:23563266
Bhatt, Samir; Gething, Peter W; Brady, Oliver J; Messina, Jane P; Farlow, Andrew W; Moyes, Catherine L; Drake, John M; Brownstein, John S; Hoen, Anne G; Sankoh, Osman; Myers, Monica F; George, Dylan B; Jaenisch, Thomas; Wint, G R William; Simmons, Cameron P; Scott, Thomas W; Farrar, Jeremy J; Hay, Simon I
Dengue virus infection can cause a wide spectrum of illness. Thrombocytopenia with concurrent haemoconcentration differentiates\\u000a dengue haemorrhagic fever from classical dengue fever. Only cases with shock or unstable vitals signs need admission in the\\u000a pediatric intensive care. The management is essentially supportive and symptomatic. The key to success is frequent monitoring\\u000a and changing strategies. A rise in hematocrit of 20%
Arun Soni; Krishan Chugh; Anil Sachdev; Dhiren Gupta
Following the terrorist attacks of September 11 and the anthrax attacks in 2001, public health entities implemented automated surveillance systems based on disease syndromes for early detection of bioterror events and to increase timeliness of responses. Despite widespread adoption, syndromic surveillance systems' ability to provide early notification of outbreaks is unproven, and there is little documentation on their role in outbreak response. We hypothesized that biosurveillance is used in practice to augment classical outbreak investigations, and we used case studies conducted in 2007-08 to determine (1) which steps in outbreak investigations were best served by biosurveillance, and (2) which steps presented the greatest opportunities for improvement. The systems used in the case studies varied in how they functioned, and there were examples in which syndromic systems had identified outbreaks before other methods. Biosurveillance was used successfully for all steps of outbreak investigations. Key advantages of syndromic systems were sensitivity, timeliness, and flexibility and as a source of data for situational awareness. Limitations of biosurveillance were a lack of specificity, reliance on chief complaint data, and a lack of formal training for users. Linking syndromic data to triage notes and medical chart data would substantially increase the value of biosurveillance in the conduct of outbreak investigations and reduce the burden on health department staff. PMID:23448272
Kaydos-Daniels, S Cornelia; Rojas Smith, Lucia; Farris, Tonya R
An outbreak of strangles, which occurred during the spring, summer and fall of 1980 on a Standardbred stud farm in eastern Alberta is described. The infective organism, Streptococcus equi, may have been introduced by an outside mare that was brought to the stud for breeding. All of the groups of horses on the farm were affected. For the most part, the disease was allowed to run its natural course. Only severely affected individuals were treated. During the outbreak, the foals were prophylactically treated with penicillin to prevent them from contracting the disease. Ten horses died of complications of strangles infection.
Piche, C. A.
Dengue viruses (DENV) serotypes 1, 2, and 3 have been causing yearly outbreaks in Brazil. In this study, we report the re-introduction of DENV2 in the coast of São Paulo State. Partial envelope viral genes were sequenced from eighteen patients with dengue fever during the 2010 epidemic. Phylogenetic analysis showed this strain belongs to the American/Asian genotype and was closely related to the virus that circulated in Rio de Janeiro in 2007 and 2008. The phylogeny also showed no clustering by clinical presentation, suggesting that the disease severity could not be explained by distinct variants or genotypes. The time of the most recent common ancestor of American/Asian genotype and the São Paulo and Rio de Janeiro (SP/RJ) monophyletic cluster was estimated to be around 40 and 10 years, respectively. Since this virus was first identified in Brazil in 2007, we suggest that it was already circulating in the country before causing the first documented outbreak. This is the first description of the 2010 outbreak in the State of São Paulo, Brazil, and should contribute to efforts to control and monitor the spread of DENVs in endemic areas.
Romano, Camila Malta; de Matos, Andreia Manso; Araujo, Evaldo Stanislau A.; Villas-Boas, Lucy Santos; da Silva, Wanessa Cardoso; Oliveira, Olimpia M. N. P. F.; Carvalho, Karina I.; de Souza, Ana Carolina Mamana; Rodrigues, Celia L.; Levi, Jose Eduardo; Kallas, Esper G.; Pannuti, Claudio Sergio
Dengue, endemic in Puerto Rico, reached a record high in 2010. To inform policy makers, we derived annual economic cost. We assessed direct and indirect costs of hospitalized and ambulatory dengue illness in 2010 dollars through surveillance data and interviews with 100 laboratory-confirmed dengue patients treated in 2008–2010. We corrected for underreporting by using setting-specific expansion factors. Work absenteeism because of a dengue episode exceeded the absenteeism for an episode of influenza or acute otitis media. From 2002 to 2010, the aggregate annual cost of dengue illness averaged $38.7 million, of which 70% was for adults (age 15+ years). Hospitalized patients accounted for 63% of the cost of dengue illness, and fatal cases represented an additional 17%. Households funded 48% of dengue illness cost, the government funded 24%, insurance funded 22%, and employers funded 7%. Including dengue surveillance and vector control activities, the overall annual cost of dengue was $46.45 million ($12.47 per capita).
Halasa, Yara A.; Shepard, Donald S.; Zeng, Wu
Recently, we showed that infection with dengue virus increases the locomotor activity of Aedes aegypti females. We speculate that the observed increased locomotor activity could potentially increase the chances of finding a suitable host and, as a consequence, the relative biting rate of infected mosquitoes. We used a mathematical model to investigate the impact of the increased locomotor activity by assuming that this activity translated into an increased biting rate for infected mosquitoes. The results show that the increased biting rate resulted in dengue outbreaks with greater numbers of primary and secondary infections and with more severe biennial epidemics. PMID:22012232
Luz, Paula Mendes; Lima-Camara, Tamara Nunes; Bruno, Rafaela Vieira; Castro, Márcia Gonçalves de; Sorgine, Marcos Henrique Ferreira; Lourenço-de-Oliveira, Ricardo; Peixoto, Alexandre Afrânio
In this study, we successfully established retrovirus-based reporter viruses pseudotyped with the precursor membrane and envelope (PrM/E) proteins of each of the four serotypes of dengue viruses, which caused the most important arboviral diseases in this century. Co-sedimentation of the dengue E protein and HIV-1 core proteins by sucrose gradient analysis of the pseudotype reporter virus of dengue virus type 2, D2(HIVluc), and detection of HIV-1 core proteins by immunoprecipitation with anti-E monoclonal antibody suggested that dengue viral proteins were incorporated into the pseudotype viral particles. The infectivity in target cells, as assessed by the luciferase activity, can be inhibited by the lysosomotropic agents, suggesting a pH-dependent mechanism of entry. Amino acid substitutions of the leucine at position 107, a critical residue at the fusion loop of E protein, with lysine resulted in severe impairment in infectivity, suggesting that entry of the pseudotype reporter virus is mediated through the fusogenic properties of E protein. With more and more dengue viral sequences available from different outbreaks worldwide, this sensitive and convenient tool has the potential to facilitate molecular characterization of the PrM/E proteins of dengue field isolates.
Hu, H.-P.; Hsieh, S.-C. [Institute of Microbiology, College of Medicine, National Taiwan University, No 1 Sec1 Jen-Ai Rd, Taipei 100, Taiwan (China); King, C.-C. [Institute of Epidemiology, College of Public Health, National Taiwan University, No 1 Sec1 Jen-Ai Rd, Taipei 100, Taiwan (China); Wang, W.-K. [Institute of Microbiology, College of Medicine, National Taiwan University, No 1 Sec1 Jen-Ai Rd, Taipei 100, Taiwan (China); Department of Internal Medicine, National Taiwan University Hospital, No 7 Chung-Shan S Rd, Taipei 100, Taiwan (China)], E-mail: firstname.lastname@example.org
This study aimed to develop a forecasting model for the incidence of dengue in Ribeirão Preto, São Paulo State, Brazil, using time series analysis. The model was performed using the Seasonal Autoregressive Integrated Moving Average (SARIMA). Firstly, we fitted a model considering monthly notifications of cases of dengue recorded from 2000 to 2008 in Ribeirão Preto. We then extracted predicted values for 2009 from the adjusted model and compared them with the number of cases observed for that year. The SARIMA (2,1,3)(1,1,1)12 model offered best fit for the dengue incidence data. The results showed that the seasonal ARIMA model predicts the number of dengue cases very effectively and reliably, and is a useful tool for disease control and prevention. PMID:21986608
Martinez, Edson Zangiacomi; Silva, Elisângela Aparecida Soares da
Based on in vitro data, the U.S. Food and Drug Administration recommends chemical disinfection of raw sprout seeds to reduce enteric pathogens contaminating the seed coats. However, little is known about the effectiveness of decontamination at preventing human disease. In 1999, an outbreak of Salmonella enterica serotype Mbandaka occurred in Oregon, Washington, Idaho, and California. Based on epidemiologic and pulsed-field gel electrophoresis evidence from 87 confirmed cases, the outbreak was linked to contaminated alfalfa seeds grown in California’s Imperial Valley. Trace-back and trace-forward investigations identified a single lot of seeds used by five sprout growers during the outbreak period. Cases of salmonellosis were linked with two sprout growers who had not employed chemical disinfection; no cases were linked to three sprout growers who used disinfection. This natural experiment provides empiric evidence that chemical disinfection can reduce the human risk for disease posed by contaminated seed sprouts.
Gill, Christopher J.; Mohle-Boetani, Janet C.; Farrar, Jeff A.; Waller, Patti L.; Hahn, Christine G.; Cieslak, Paul R.
Seasonality is a driving force that has major impact on the spatio-temporal dynamics of natural systems and their populations. This is especially true for the transmission of common infectious diseases such as influenza, measles, chickenpox, and pertussis. Here we gain new insights into the nonlinear dynamics of recurrent diseases through the analysis of the classical seasonally forced SIR epidemic model. Despite many efforts over the last decades, it has been difficult to gain general analytical insights because of the complex synchronization effects that can evolve between the external forcing and the model's natural oscillations. The analysis advanced here attempts to make progress in this direction by focusing on the dynamics of ``skips'' where we identify and predict years in which the epidemic is absent rather than outbreak years. Skipping events are intrinsic to the forced SIR model when parameterised in the chaotic regime. In fact, it is difficult if not impossible to locate realistic chaotic parameter regimes in which outbreaks occur regularly each year. This contrasts with the well known Rossler oscillator whose outbreaks recur regularly but whose amplitude vary chaotically in time (Uniform Phase Chaotic Amplitude oscillations). The goal of the present study is to develop a ``language of skips'' that makes it possible to predict under what conditions the next outbreak is likely to occur, and how many ``skips'' might be expected after any given outbreak. We identify a new threshold effect and give clear analytical conditions that allow accurate predictions. Moreover, the time of occurrence (i.e., phase) of an outbreak proves to be a useful new parameter that carries important epidemiological information. In forced systems, seasonal changes can prevent late-initiating outbreaks (i.e., having high phase) from running to completion. These principles yield forecasting tools that should have relevance for the study of newly emerging and reemerging diseases.
One-Step Rapid Reverse Transcription-PCR Assay for Detecting and Typing Dengue Viruses with GC Tail and Induced Fluorescence Resonance Energy Transfer Techniques for Melting Temperature and Color Multiplexing
Background: Dengue fever is an arthropod-borne infec- tion caused by dengue viruses (DVs; DEN-1 to DEN-4). Early diagnosis is critical to prevent severe disease progression and the spreading of DV because no vac- cine or specific treatment is available; therefore, a rapid and specific diagnostic assay capable of detecting and typing all serotypes would be ideal. Methods: We amplified RNA
Constance L. H. Lo; Shea Ping Yip; Peter K. C. Cheng; Tony S. S. To; Wilina W. L. Lim; Polly H. M. Leung
Dengue is the most important arboviral infection of humans. Thrombocytopenia is frequently observed in the course of infection and haemorrhage may occur in severe disease. The degree of thrombocytopenia correlates with the severity of infection, and may contribute to the risk of haemorrhage. As a result of this prophylactic platelet transfusions are sometimes advocated for the prevention of haemorrhage. There
James Whitehorn; Rosmari Rodriguez Roche; Maria G. Guzman; Eric Martinez; Wilmar Villamil Gomez; Leonard Nainggolan; Ida Safitri Laksono; Ajay Mishra; Lucy Lum; Abul Faiz; Amadou Sall; Joshua Dawurung; Alvaro Borges; Yee-Sin Leo; Lucille Blumberg; Daniel G. Bausch; Axel Kroeger; Olaf Horstick; Guy Thwaites; Heiman Wertheim; Mattias Larsson; Tran Tinh Hien; Rosanna Peeling; Bridget Wills; Cameron Simmons; Jeremy Farrar
BackgroundTransmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that
Mammen P Mammen; Chusak Pimgate; Constantianus J. M Koenraadt; Alan L Rothman; Jared Aldstadt; Ananda Nisalak; Richard G Jarman; James W Jones; Anon Srikiatkhachorn; Charity Ann Ypil-Butac; Arthur Getis; Suwich Thammapalo; Amy C Morrison; Daniel H Libraty; Sharone Green; Thomas W Scott
Background Competitive displacement of a weakly virulent pathogen strain by a more virulent strain is one route to disease emergence. However the mechanisms by which pathogens compete for access to hosts are poorly understood. Among vector-borne pathogens, variation in the ability to infect vectors may effect displacement. The current study focused on competitive displacement in dengue virus serotype 3 (DENV3), a mosquito-borne pathogen of humans. In Sri Lanka in the 1980's, a native DENV3 strain associated with relatively mild dengue disease was displaced by an invasive DENV3 strain associated with the most severe disease manifestations, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), resulting in an outbreak of DHF/DSS. Here we tested the hypothesis that differences between the invasive and native strain in their infectivity for Aedes aegypti mosquitoes, the primary vector of DENV, contributed to the competitive success of the invasive strain Results To be transmitted by a mosquito, DENV must infect and replicate in the midgut, disseminate into the hemocoel, infect the salivary glands, and be released into the saliva. The ability of the native and invasive DENV3 strains to complete the first three steps of this process in Aedes aegypti mosquitoes was measured in vivo. The invasive strain infected a similar proportion of mosquitoes as the native strain but replicated to significantly higher titers in the midgut and disseminated with significantly greater efficiency than the native strain. In contrast, the native and invasive strain showed no significant difference in replication in cultured mosquito, monkey or human cells. Conclusion The invasive DENV3 strain infects and disseminates in Ae. aegypti more efficiently than the displaced native DENV3 strain, suggesting that the invasive strain is transmitted more efficiently. Replication in cultured cells did not adequately characterize the known phenotypic differences between native and invasive DENV3 strains. Infection dynamics within the vector may have a significant impact on the spread and replacement of dengue virus lineages.
Hanley, Kathryn A; Nelson, Jacob T; Schirtzinger, Erin E; Whitehead, Stephen S; Hanson, Christopher T
The World Health Organization (WHO) estimates that there are over 50 million cases of dengue fever reported annually and approximately 2.5 billion people are at risk. Mild dengue fever presents with headache, fever, rash, myalgia, osteogenic pain, and lethargy. Severe disease can manifest as dengue shock syndrome (DSS) or dengue hemorrhagic fever (DHF). Symptoms of DSS\\/DHF are leukopenia, low blood
David G Nielsen
To characterize the molecular basis for the hemostatic defects of dengue infections, a study was con- ducted in Bangkok, Thailand. Febrile children (n 68) hospitalized with suspected dengue were enrolled before their clinical syndromes were classified as either dengue fever (DF) or dengue hemorrhagic fever (DHF). Hospital course and outcome were recorded; blood was obtained during the febrile illness (S1),
CHITRA KRISHNAMURTI; SIRIPEN KALAYANAROOJ; MARY A. CUTTING; RAQUEL A. PEAT; STEPHEN W. ROTHWELL; THOMAS J. REID; SHARONE GREEN; ANANDA NISALAK; TIMOTHY P. ENDY; DAVID W. VAUGHN; SUCHITRA NIMMANNITYA; BRUCE L. INNIS
The age distribution of cases of dengue hemorrhagic fever and dengue shock syndrome (DHF\\/DSS) in infants under the age of 1 year are reported from Bangkok, Thailand, and for the first time for Ho Chi Minh City, Vietnam; Yangon, Myanmar; and Surabaya, Indonesia. The four dengue viruses were isolated from Thai infants, all of whom were having a primary dengue
Scott B. Halstead; Nguyen Trong Lan; Thein Thein Myint; Than Nu Shwe; Ananda Nisalak; Siripen Kalyanarooj; Suchitra Nimmannitya; Soegeng Soegijanto; David W. Vaughn; Timothy P. Endy
The number of cases and severity of disease associated with dengue infection in Sri Lanka has been increasing since 1989, when the first epidemic of dengue hemorrhagic fever was recorded. We identified a new dengue virus 1 strain circulating in Sri Lanka that coincided with the 2009 dengue epidemic. PMID:22099096
Tissera, Hasitha A; Ooi, Eng Eong; Gubler, Duane J; Tan, Ying; Logendra, Barathy; Wahala, Wahala M P B; de Silva, Aravinda M; Abeysinghe, M R Nihal; Palihawadana, Paba; Gunasena, Sunethra; Tam, Clarence C; Amarasinghe, Ananda; Letson, G William; Margolis, Harold S; De Silva, Aruna Dharshan
The number of cases and severity of disease associated with dengue infection in Sri Lanka has been increasing since 1989, when the first epidemic of dengue hemorrhagic fever was recorded. We identified a new dengue virus 1 strain circulating in Sri Lanka that coincided with the 2009 dengue epidemic.
Tissera, Hasitha A.; Ooi, Eng Eong; Gubler, Duane J.; Tan, Ying; Logendra, Barathy; Wahala, Wahala M.P.B.; de Silva, Aravinda M.; Abeysinghe, M.R. Nihal; Palihawadana, Paba; Gunasena, Sunethra; Tam, Clarence C.; Amarasinghe, Ananda; Letson, G. William; Margolis, Harold S.
BACKGROUND: Dengue is a mosquito-borne viral infection that is now endemic in most tropical countries. In Thailand, dengue fever\\/dengue hemorrhagic fever is a leading cause of hospitalization and death among children. A longitudinal study among 1750 people in two rural and one urban sites in northern Thailand from 2001 to 2003 studied spatial and temporal determinants for recent dengue infection
Sophie O Vanwambeke; Birgit HB van Benthem; Nardlada Khantikul; Chantal Burghoorn-Maas; Kamolwan Panart; Linda Oskam; Eric F Lambin; Pradya Somboon
This online portal features a research project funded by The Grand Challenges in Global Health Initiative to develop new strategies to control mosquitoes that transmit human disease. Specifically, the project is focused on a method to reduce dengue transmission using naturally occurring bacterial symbionts that reduce mosquito life span. The site includes a background of this work, participating research programs and researchers, project publications, current progress, news and events, and FAQs.
Initiative, The G.
A report of 19 cases of serologically-proven dengue hemorrhagic fever (DHF) in infants aged 3-12 months who were admitted to the Department of Pediatrics, Chon Buri Regional Hospital, Thailand, during 1995 to 1998. Subjects were 8 males and 11 females, with the peak age of 8 months. Four cases (21%) had DHF and other common co-infections ie pneumonia (2 cases),
\\u000a Each of the DENV serotypes can cause the full spectrum of dengue illness. Epidemiological studies have implicated preexisting\\u000a heterotypic DENV antibody as a risk factor for more severe disease upon secondary DENV infection. For these reasons, a successful\\u000a DENV vaccine must protect against all four DENV serotypes. Live attenuated DENV vaccine candidates are the furthest along\\u000a in development and clinical
Anna P. Durbin; Stephen S. Whitehead
Introduction. – Transmitted by Aedes mosquitoes all over the inter-tropical area, Dengue fever is the leading arboviral disease in humans. It is also an emerging disease.Current knowledge and key points. – Increasing morbidity-mortality, and geographical expansion are the drastic changes noted in the recent epidemiology of the disease. They are related to those occurring at the bio-climatic, socio-demographic and behavioural levels, which
M Strobel; I Lamaury
The burden of dengue in Nicaragua has been steadily rising during the last three decades; however, there have been few efforts to quantify the burden (measured in disability-adjusted life years [DALYs]) and cost to society. Using primary data from the Nicaraguan Ministry of Health (MINSA), the total cost and burden of dengue were calculated from 1996 to 2010. Total costs included both direct costs from medical expenditures and prevention activities and indirect costs from lost productivity. The annual disease burden ranged from 99 to 805 DALYs per million, with a majority associated with classic dengue fever. The total cost was estimated to be US$13.5 million/year (range: US$5.1–27.6 million). This analysis can help improve allocation of dengue control resources in Nicaragua and the region. As one of the most comprehensive analyses of its type to date in Nicaragua and Latin America, this study can serve as a model to determine the burden and cost of dengue.
Wettstein, Zachary S.; Fleming, Michael; Chang, Aileen Y.; Copenhaver, David J.; Wateska, Angela R.; Bartsch, Sarah M.; Lee, Bruce Y.; Kulkarni, Rajan P.
Dengue is the most important arboviral disease of humans with over half of the world’s population living in areas of risk. The frequency and magnitude of epidemic dengue have increased dramatically in the past 40 years as the viruses and the mosquito vectors have both expanded geographically in the tropical regions of the world. There are many factors that have contributed to this emergence of epidemic dengue, but only three have been the principal drivers: 1) urbanization, 2) globalization and 3) lack of effective mosquito control. The dengue viruses have fully adapted to a human-Aedes aegypti-human transmission cycle, in the large urban centers of the tropics, where crowded human populations live in intimate association with equally large mosquito populations. This setting provides the ideal home for maintenance of the viruses and the periodic generation of epidemic strains. These cities all have modern airports through which 10s of millions of passengers pass each year, providing the ideal mechanism for transportation of viruses to new cities, regions and continents where there is little or no effective mosquito control. The result is epidemic dengue. This paper discusses this unholy trinity of drivers, along with disease burden, prevention and control and prospects for the future.
Gubler, Duane J.
We argue that using more natural blood feeding methods to study mosquito vector competence for dengue viruses and exploring the effect of viral infection on other mosquito life-history traits that influence vectorial capacity will significantly advance our understanding of dengue epidemiology. PMID:23295765
Lambrechts, Louis; Failloux, Anna-Bella
The number of cases of severe dengue disease continues to grow in endemic areas of southeast Asia, Central and South America, and other subtropical regions. Children bear the greatest burden of disease, and the development of an effective vaccine remains a global public health priority. A tetravalent vaccine is urgently needed and must be effective against all four dengue virus
Joseph E. Blaney; Anna P. Durbin; Brian R. Murphy; Stephen S. Whitehead
Dengue virus is a mosquito borne, positive strand RNA virus responsible for hundreds of thousands of illnesses annually. No effective vaccine exists for any of the four dengue serotypes. The ultimate goal of our research is the production of a vaccine for...
J. M. Ivy
Nucleotide sequence analysis was performed on 14 dengue virus isolates (13 dengue-2 viruses and 1 dengue-3 virus) recovered from febrile soldiers in Somalia in 1993. The dengue-2 viruses were most closely related to dengue-2 virus recovered in Somalia in 1984. However, differences in nucleotide sequence (0.35% to 1.35%) were evident among the 1993 isolates. These differences were closely associated with
Niranjan Kanesa-thasan; Gwong-Jen J. Chang; Bonnie L. Smoak; Alan Magill; M. Jeanne Burrous; Charles H. Hoke
BackgroundDengue is the most prevalent mosquito borne infection worldwide. Vertical transmissions after maternal dengue infection to the fetus and pregnancy losses in relation to dengue illness have been reported. The relationship of dengue to miscarriage is not known.MethodWe aimed to establish the relationship of recent dengue infection and miscarriage. Women who presented with miscarriage (up to 22 weeks gestation) to
Peng Chiong Tan; May Zaw Soe; Khaing Si Lay; Seok Mui Wang; Shamala Devi Sekaran; Siti Zawiah Omar
Dengue is the most common mosquito-borne viral disease in humans. The spread of both mosquito vectors and viruses has led to the resurgence of epidemic dengue fever (a self-limited flu-like syndrome) and the emergence of dengue hemorrhagic fever (severe dengue with bleeding abnormalities) in urban centers of the tropics. There are no animal or laboratory models of dengue disease; indirect
Raymond Cologna; Philip M. Armstrong; Rebeca Rico-Hesse
Clostridium perfringens is estimated to be the second most common bacterial cause of foodborne illness in the United States, causing one million illnesses each year. Local, state, and territorial health departments voluntarily report C. perfringens outbreaks to the U.S. Centers for Disease Control and Prevention through the Foodborne Disease Outbreak Surveillance System. Our analysis included outbreaks confirmed by laboratory evidence during 1998-2010. A food item was implicated if C. perfringens was isolated from food or based on epidemiologic evidence. Implicated foods were classified into one of 17 standard food commodities when possible. From 1998 to 2010, 289 confirmed outbreaks of C. perfringens illness were reported with 15,208 illnesses, 83 hospitalizations, and eight deaths. The number of outbreaks reported each year ranged from 16 to 31 with no apparent trend over time. The annual number of outbreak-associated illnesses ranged from 359 to 2,173, and the median outbreak size was 24 illnesses. Outbreaks occurred year round, with the largest number in November and December. Restaurants (43%) were the most common setting of food preparation. Other settings included catering facility (19%), private home (16%), prison or jail (11%), and other (10%). Among the 144 (50%) outbreaks attributed to a single food commodity, beef was the most common commodity (66 outbreaks, 46%), followed by poultry (43 outbreaks, 30%), and pork (23 outbreaks, 16%). Meat and poultry outbreaks accounted for 92% of outbreaks with an identified single food commodity. Outbreaks caused by C. perfringens occur regularly, are often large, and can cause substantial morbidity yet are preventable if contamination of raw meat and poultry products is prevented at the farm or slaughterhouse or, after contamination, if these products are properly handled and prepared, particularly in restaurants and catering facilities. PMID:23379281
Grass, Julian E; Gould, L Hannah; Mahon, Barbara E
A commercial dengue NS1 antigen-capture ELISA was evaluated to demonstrate its potential application for early laboratory diagnosis of acute dengue virus infection. Dengue virus NS1 antigen was detected in 199 of 213 acute serum samples from patients with laboratory confirmation of acute dengue virus infection but none of the 354 healthy blood donors’ serum specimens. The dengue NS1 antigen-capture ELISA
V. Kumarasamy; A. H. Abdul Wahab; S. K. Chua; Z. Hassan; Y. K. Chem; M. Mohamad; K. B. Chua
Dengue fever and dengue hemorrhagic fever constitute a substantial health burden on the population in Thailand. In this study, the impact of symptomatic dengue virus infection on the families of patients hospitalized at the Kamphaeng Phet Provincial Hospital with laboratory-confirmed dengue in 2001 was assessed, and the disability-adjusted life years (DALYs) lost for fatal and non-fatal cases of dengue were
DANIELLE V. CLARK; MAMMEN P. MAMMEN JR.; ANANDA NISALAK; VIRAT PUTHIMETHEE; TIMOTHY P. ENDY
Dengue virus occurs as four distinct serotypes, called Dengue 1, 2, 3, and 4. Symptomatic dengue virus infection ranges from a self limited febrile illness, dengue fever (DF), to a more severe disease, dengue hemorrhagic fever\\/dengue shock syndrome (DHF\\/DSS). The anti-Dengue treatment is severely hampered as no specific therapeutic agents are available. Even present treatment strategies for Dengue are more
Monika Jain; L. Ganju; A. Katiyal; Y. Padwad; K. P. Mishra; S. Chanda; D. Karan; K. M. S. Yogendra; R. C. Sawhney
Dengue fever (DF) is a mosquito-borne disease that significantly endangers the well-being of people in most tropical Asia-Pacific areas. The transmission of DF is inherently a spatial process, requiring susceptible humans encountering infectious mosquito. The relationships between humans, mosquito and environment underpin the dynamics and patterns of the epidemic. In this article, the objective is to find out the key abiotic factors in the spatial dynamics of DF. An interdisciplinary study has been carried out by taking advantage of statistics, geographical information science, and remote sensing technologies. The case study is the DF outbreak in the Chinese city of Guangzhou throughout the year of 2002--the most serious DF outbreak in the recent decade. This study shows that the presence and abundance of DF cases can be associated with (a) socioeconomic factors relating to urbanization and (b) meteorological factors favoring mosquito survival. PMID:21852418
Li, Sen; Tao, Haiyan; Xu, Yong
In Angola, nearly 900 cases of polio have occurred in one of the largest polio outbreaks ever recorded in Africa. It is noted that 58 children have already died, with almost all cases reported in children under 5 years old who have never been immunized. Such an outbreak was sparked by renewed fighting which displaced families to over-crowded slums in the capital Luanda. To this effect, the Government of Angola acted quickly to control the epidemic through an emergency vaccination campaign. Working with WHO and the UN Children's Fund, the Ministry of Health vaccinated more than 900,000 children during the campaign in Luanda and Benguela province in April. In addition to given caution to the world against failing to vaccinate children, the massive outbreak has also given new impetus to negotiations between Angola's warring parties to hold fire for polio vaccination. PMID:12349797
Mathematical models of viral transmission and control are important tools for assessing the threat posed by deliberate release of the smallpox virus and the best means of containing an outbreak. Models must balance biological realism against limitations of knowledge, and uncertainties need to be accurately communicated to policy-makers. Smallpox poses the particular challenge that key biological, social and spatial factors affecting disease spread in contemporary populations must be elucidated largely from historical studies undertaken before disease eradication in 1979. We review the use of models in smallpox planning within the broader epidemiological context set by recent outbreaks of both novel and re-emerging pathogens.
Ferguson, Neil M.; Keeling, Matt J.; John Edmunds, W.; Gani, Raymond; Grenfell, Bryan T.; Anderson, Roy M.; Leach, Steve
We examined outbreak investigations conducted around the world from 1988 to 1999 by the Centers for Disease Control and Prevention's Epidemic Intelligence Service. In 44 (4.0%) of 1,099 investigations, identified causative agents had bioterrorism potential. In six investi- gations, intentional use of infectious agents was consid- ered. Healthcare providers reported 270 (24.6%) outbreaks and infection control practitioners reported 129 (11.7%);
David A. Ashford; Robyn M. Kaiser; Michael E. Bales; Kathleen Shutt; Amee Patrawalla; Andre McShan; Jordan W. Tappero; Bradley A. Perkins; Andrew L. Dannenberg
A multicenter effort was begun in 1994 to characterize the pathophysiology of dengue using a study design that minimized patient selection bias by offering enrollment to all children with undifferentiated fever for <72 h. In the first year, 189 children were enrolled (age range, 8 months to 14 years). Thirty-two percent of these children had dengue infections (60 volunteers). The percentage of children with a secondary dengue infection was 93%, with only 4 (7%) having a primary dengue infection. The virus isolation rate from the plasma of children with dengue was 98%. Viremia correlated highly with temperature. All four dengue virus serotypes were isolated at both study sites. This study demonstrates that all four serotypes of dengue virus can cause dengue hemorrhagic fever, that all dengue patients as defined by serology experience viremia during the febrile phase, and that as fever subsides, so does viremia. PMID:9237696
Vaughn, D W; Green, S; Kalayanarooj, S; Innis, B L; Nimmannitya, S; Suntayakorn, S; Rothman, A L; Ennis, F A; Nisalak, A
Dengue virus (DENV) is transmitted to humans through the bite of mosquitoes. In November 2010, a dengue outbreak was reported in Monroe County in southern Florida (FL), including greater than 20 confirmed human cases. The virus collected from the human cases was verified as DENV serotype 1 (DENV-1) and one isolate was provided for sequence analysis. RNA was extracted from the DENV-1 isolate and was used in reverse transcription polymerase chain reaction (RT-PCR) to amplify PCR fragments to sequence. Nucleic acid primers were designed to generate overlapping PCR fragments that covered the entire genome. The DENV-1 isolate found in Key West (KW), FL was sequenced for whole genome characterization. Sequence assembly, Genbank searches, and recombination analyses were performed to verify the identity of the genome sequences and to determine percent similarity to known DENV-1 sequences. We show that the KW DENV-1 strain is 99% identical to Nicaraguan and Mexican DENV-1 strains. Phylogenetic and recombination analyses suggest that the DENV-1 isolated in KW originated from Nicaragua (NI) and the KW strain may circulate in KW. Also, recombination analysis results detected recombination events in the KW strain compared to DENV-1 strains from Puerto Rico. We evaluate the relative growth of KW strain of DENV-1 compared to other dengue viruses to determine whether the underlying genetics of the strain is associated with a replicative advantage, an important consideration since local transmission of DENV may result because domestic tourism can spread DENVs.
Shin, Dongyoung; Richards, Stephanie L.; Alto, Barry W.; Bettinardi, David J.; Smartt, Chelsea T.
Dengue virus (DENV) is transmitted to humans through the bite of mosquitoes. In November 2010, a dengue outbreak was reported in Monroe County in southern Florida (FL), including greater than 20 confirmed human cases. The virus collected from the human cases was verified as DENV serotype 1 (DENV-1) and one isolate was provided for sequence analysis. RNA was extracted from the DENV-1 isolate and was used in reverse transcription polymerase chain reaction (RT-PCR) to amplify PCR fragments to sequence. Nucleic acid primers were designed to generate overlapping PCR fragments that covered the entire genome. The DENV-1 isolate found in Key West (KW), FL was sequenced for whole genome characterization. Sequence assembly, Genbank searches, and recombination analyses were performed to verify the identity of the genome sequences and to determine percent similarity to known DENV-1 sequences. We show that the KW DENV-1 strain is 99% identical to Nicaraguan and Mexican DENV-1 strains. Phylogenetic and recombination analyses suggest that the DENV-1 isolated in KW originated from Nicaragua (NI) and the KW strain may circulate in KW. Also, recombination analysis results detected recombination events in the KW strain compared to DENV-1 strains from Puerto Rico. We evaluate the relative growth of KW strain of DENV-1 compared to other dengue viruses to determine whether the underlying genetics of the strain is associated with a replicative advantage, an important consideration since local transmission of DENV may result because domestic tourism can spread DENVs. PMID:24098658
Shin, Dongyoung; Richards, Stephanie L; Alto, Barry W; Bettinardi, David J; Smartt, Chelsea T
The literature of the outbreaks of 'epidemic neuromyasthenia' (ENM) from 1934 to 1955 has been selected to show that the disease affects other people besides young adult females in hospitals and nursing homes. There have been district epidemics, in which the male: female ratio was almost even and several male outbreaks affecting soldiers in barracks. Some outbreaks appear to have
J. G. Parish
OBJECTIVES: This study describes the epidemiology of raw milk-associated outbreaks reported to the Centers for Disease Control and Prevention from 1973 through 1992. METHODS: Surveillance data for each reported raw milk-associated outbreak were reviewed. A national survey was conducted to determine the legal status of intrastate raw milk sales for the period 1973 through 1995. RESULTS: Forty-six raw milk-associated outbreaks were reported during the study period; 40 outbreaks (87%) occurred in states where the intrastate sale of raw milk was legal. CONCLUSIONS: Consumption of raw milk remains a preventable cause of foodborne disease outbreaks.
Headrick, M L; Korangy, S; Bean, N H; Angulo, F J; Altekruse, S F; Potter, M E; Klontz, K C
The Sanofi Pasteur tetravalent dengue vaccine candidate is composed of 4 recombinant live attenuated vaccines based on a yellow fever vaccine 17D (YFV 17D) backbone, each expressing the prM and envelope genes of one of the four dengue virus serotypes. Pre-clinical studies have demonstrated that the TV dengue vaccine is genetically and phenotypically stable, non-hepatotropic, less neurovirulent than YFV 17D and does not infect mosquitoes by the oral route. In vitro and in vivo preclinical studies also showed that the TV dengue vaccine induced controlled stimulation in human dendritic cells and significant immune responses in monkeys. TV dengue vaccine reactogenicity, viraemia induction and antibody responses were investigated in three Phase I trials in the USA, the Philippines and Mexico, in a two or three-dose regimen over a 12 month period. Results showed that the majority of adverse events were mild to moderate and transient in nature. Viraemia was transient and low, and was not increased after initial dengue TV administration, even in the case of incomplete responses. ?Seropositivity [?10 in a PRNT 50 assay] was 100% for all four serotypes in flavivirus-naive adults injected with 3 doses of TV dengue vaccine in the USA. Similarly, seropositivity was 88-100% following three administrations in flavivirus-naive Mexican children aged 2-5 years. Furthermore, the proportion of seropositive subjects increased with each dengue TV injection in the Philippines where baseline flavivirus immunity was high. Responses were also monitored at the cellular level in humans, and their level and nature were in good agreement with the observed safety and the immunogenicity of the vaccine. Finally, the challenges inherent to the development of such TV dengue vaccines will also be discussed in the last part of this review. In conclusion, preclinical and clinical results support the favorable immunogenicity and short-term safety of the dengue TV vaccine. An extensive clinical development program for dengue TV is underway including completion of the enrollment of 4,000 4-11 years old children in an efficacy trial in Thailand, in an area of high dengue incidence. Assuming continued successful outcomes, initial submissions to regulatory authorities are envisaged within a 5-year period. PMID:20861669
Guy, Bruno; Saville, Melanie; Lang, Jean
Eighteen dengue viruses (DENVs) representing all four serotypes, isolated from pediatric patients at children's hospital, Queen Sirikit National Institute of Child Health, Bangkok, Thailand exhibiting a diverse spectrum of disease ranging from uncomplicated dengue fever (DF) to severe dengue hemorrhagic fever (DHF), were tested for their ability to attach to host cells, replicate and interfere with the IFN? signaling pathway
Ratree Takhampunya; Dupeh R. Palmer; Sasha McClain; David A. Barvir; Julia Lynch; Richard G. Jarman; Stephen Thomas; Robert V. Gibbons; Timothy H. Burgess; Peifang Sun; Edwin Kamau; Robert Putnak; Chunlin Zhang
Despite advances in water management and sanitation, waterborne disease outbreaks continue to occur in the United States. CDC collects data on waterborne disease outbreaks submitted from all states and territories* through the Waterborne Disease and Outbreak Surveillance System.† During 2009-2010, the most recent years for which finalized data are available, 33 drinking water-associated outbreaks were reported, comprising 1,040 cases of illness, 85 hospitalizations, and nine deaths. Legionella accounted for 58% of outbreaks and 7% of illnesses, and Campylobacter accounted for 12% of outbreaks and 78% of illnesses. The most commonly identified outbreak deficiencies§ in drinking water-associated outbreaks were Legionella in plumbing¶ systems (57.6%), untreated ground water (24.2%), and distribution system deficiencies (12.1%), suggesting that efforts to identify and correct these deficiencies could prevent many outbreaks and illnesses associated with drinking water. In addition to the drinking water outbreaks, 12 outbreaks associated with other nonrecreational water** were reported, comprising 234 cases of illness, 51 hospitalizations, and six deaths. Legionella accounted for 58% of these outbreaks, 42% of illnesses, 96% of hospitalizations, and all deaths. Public health, regulatory, and industry professionals can use this information to target prevention efforts against pathogens, infrastructure problems, and water sources associated with waterborne disease outbreaks. PMID:24005226
Dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) are little known and topics studied in the context of transplant patients (especially in cardiac transplants). In our knowled- ge there are no reports in the literature on dengue cases in cardiac transplant patients. Objective. To make the report of a patient who develops a hemorrhagic dengue and
Eduardo Contreras Zúñiga
As part of an intensified monitoring program for foodborne disease outbreaks in Finland, waterborne outbreaks were investigated for viruses. The diagnostic procedure included analysis of patients' stool samples by electron microscopy and reverse transcription–polymerase chain reaction (RT-PCR) for noroviruses and astroviruses. When these test results were positive for a virus, the water sample was analyzed. Virus concentration was based on positively charged filters from 1-L samples. Of the total 41 waterborne outbreaks reported during the observation period (1998–2003), samples from 28 outbreaks were available for analysis. As judged by RT-PCR results from patient samples, noroviruses caused 18 outbreaks. In 10 outbreaks, the water sample also yielded a norovirus. In all but 1 instance, the amplicon sequence was identical to that recovered from the patients. The ubiquity of waterborne norovirus outbreaks calls for measures to monitor water for viruses.
Miettinen, Ilkka T.; von Bonsdorff, Carl-Henrik
Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease. PMID:14636482
Horta Veloso, Henrique; Ferreira Júnior, João Anísio; Braga de Paiva, Joyce Morgana; Faria Honório, Júlio; Junqueira Bellei, Nancy C; Vicenzo de Paola, Angelo Amato
Dengue is an expanding public health problem, and an effective vaccine remains elusive. This review discusses how the significant influence of sequential infection with different dengue virus serotypes on the severity of disease can be viewed in terms of beneficial and detrimental effects of heterologous immunity. A more complete understanding of these effects is likely to be critical for predicting optimal vaccine-induced immune responses.
Rothman, Alan L.
Dengue hemorrhagic fever (DHF) is a potentially fatal manifestation of an infection with the mosquito-borne dengue virus. Because of the social and economic costs of DHF, many countries in Asia and South America have initiated public health measures aimed at vector control. Despite these measures, DHF incidence rates do not appear to be declining. The effectiveness of vector control in
Yoshiro Nagao; Katia Koelle
Summary: Much remains to be learned about the pathogenesis of the different manifestations of dengue virus (DENV) infections in humans. They may range from subclinical infection to dengue fever, dengue hemorrhagic fever (DHF), and eventually dengue shock syndrome (DSS). As both cell tropism and tissue tropism of DENV are considered major determinants in the pathogenesis of dengue, there is a critical need for adequate tropism assays, animal models, and human autopsy data. More than 50 years of research on dengue has resulted in a host of literature, which strongly suggests that the pathogenesis of DHF and DSS involves viral virulence factors and detrimental host responses, collectively resulting in abnormal hemostasis and increased vascular permeability. Differential targeting of specific vascular beds is likely to trigger the localized vascular hyperpermeability underlying DSS. A personalized approach to the study of pathogenesis will elucidate the basis of individual risk for development of DHF and DSS as well as identify the genetic and environmental bases for differences in risk for development of severe disease.
Martina, Byron E. E.; Koraka, Penelope; Osterhaus, Albert D. M. E.
The mechanisms underlying the pathogenesis of dengue hemorrhagic fever (DHF) remain poorly understood. Intriguing evidence suggest a role for viral strain differences. Consistent genetic differences exist in the envelope glycoproteins of dengue 2 strains ...
N. C. Martin
Epidemic dengue hemorrhagic fever recurred in 1967 on an island in the Gulf of Thailand. All cases seen were categorized by clinical syndrome as shock, hemorrhagic fever, dengue fever, or undifferentiated fever. Paired serum samples were examined for HI, ...
P. E. Winter S. Nantapanich A. Nisalak S. Udomsakdi R. W. Dewey
The re-emergence and subsequent failure to control dengue in Latin America provides a compelling illustration of the clinical, political and socio-economic challenges to eradicating dengue across the world. Insufficient political commitment, inadequate financial resources and increased urbanisation have contributed to the re-emergence and dramatic increase in dengue fever and dengue haemorrhagic fever in all 19 Latin American countries previously certified
Roberto Tapia-Conyer; Jorge F. Méndez-Galván; Héctor Gallardo-Rincón
The four dengue virus serotypes (DENV1–4) cause the most prevalent mosquito-borne viral disease affecting humans worldwide. In 2009, Nicaragua experienced the largest dengue epidemic in over a decade, marked by unusual clinical presentation, as observed in two prospective studies of pediatric dengue in Managua. From August 2009–January 2010, 212 dengue cases were confirmed among 396 study participants at the National
Gamaliel Gutierrez; Katherine Standish; Federico Narvaez; Maria Angeles Perez; Saira Saborio; Douglas Elizondo; Oscar Ortega; Andrea Nuñez; Guillermina Kuan; Angel Balmaseda; Eva Harris
When a pathogen is rare in a host population, there is a chance that it will die out because of stochastic effects instead of causing a major epidemic. Yet no criteria exist to determine when the pathogen increases to a risky level, from which it has a large chance of dying out, to when a major outbreak is almost certain. We introduce such an outbreak threshold (T0), and find that for large and homogeneous host populations, in which the pathogen has a reproductive ratio R0, on the order of 1/Log(R0) infected individuals are needed to prevent stochastic fade-out during the early stages of an epidemic. We also show how this threshold scales with higher heterogeneity and R0 in the host population. These results have implications for controlling emerging and re-emerging pathogens.
Hartfield, Matthew; Alizon, Samuel
SUMMARY The purpose of this study was to examine global epidemiological trends in human norovirus (NoV) outbreaks by transmission route and setting, and describe relationships between these characteristics, viral attack rates, and the occurrence of genogroup I (GI) or genogroup II (GII) strains in outbreaks. We analysed data from 902 RT-PCR-confirmed, human NoV outbreaks extracted from a systematic review of articles published from 1993 to 2011 and indexed under the terms “norovirus” and “outbreak.” Multivariate regression analyses demonstrated that foodservice and winter outbreaks were significantly associated with higher attack rates. Food- and waterborne outbreaks were associated with multiple strains (GI+GII). Waterborne outbreaks were significantly associated with GI strains, while healthcare-related and winter outbreaks were associated with GII strains. These results identify important trends for epidemic NoV detection, prevention, and control.
Matthews, J. E.; Dickey, B. W.; Miller, R. D.; Felzer, J. R.; Dawson, B. P.; Lee, A. S.; Rocks, J. J.; Kiel, J.; Montes, J. S.; Moe, C. L.; Eisenberg, J. N. S.; Leon, J. S.
BACKGROUND: Dengue is endemic in Cambodia (pop. estimates 14.4 million), a country with poor health and economic indicators. Disease burden estimates help decision makers in setting priorities. Using recent estimates of dengue incidence in Cambodia, we estimated the cost of dengue and its burden using disability adjusted life years (DALYs). METHODS: Recent population-based cohort data were used to calculate direct
Julien Beauté; Sirenda Vong
\\u000a Dengue, dengue haemorrhagic fever and dengue shock syndrome are endemic throughout South East Asia where they present a serious\\u000a public health concern. The current status of these diseases in Thailand is described along with the challenges that confront\\u000a those who seek to control the spread of these diseases.
Apiwat Tawatsin; Usavadee Thavara
Dengue is a re-emergent vector-borne disease affecting large portions of the world's population living in the tropics and subtropics. The virus is transmitted through the bites of female Aedes aegypti mosquitoes, and it is widely believed that these bites occur primarily in the daytime. The transmission of dengue is a complicated process, and one of the main sources of this complexity is due to the movement of people, e.g. between home and their places of work. Hence, the mechanics of disease progression may also differ between day and night. A discrete-time multi-patch dengue transmission model which takes into account the mobility of people as well as processes of infection, recovery, recruitment, mortality, and outbound and return movements is considered here. One patch (the city) is connected to all other patches (the villages) in a spoke-like network. We obtain here the basic reproductive ratio (0) of the transmission model which represents a threshold for an epidemic to occur. Dynamical analysis for vector control, human treatment and vaccination, and different kinds of mobility are performed. It is shown that changes in human movement patterns can, in some situations, affect the ability of the disease to persist in a predictable manner. We conclude with biological implications for the prevention and control of dengue virus transmission. PMID:23475426
Nevai, Andrew L; Soewono, Edy
Dengue is the most important arboviral infection of humans. Thrombocytopenia is frequently observed in the course of infection and haemorrhage may occur in severe disease. The degree of thrombocytopenia correlates with the severity of infection, and may contribute to the risk of haemorrhage. As a result of this prophylactic platelet transfusions are sometimes advocated for the prevention of haemorrhage. There is currently no evidence to support this practice, and platelet transfusions are costly and sometimes harmful. We conducted a global survey to assess the different approaches to the use of platelets in dengue. Respondents were all physicians involved with the treatment of patients with dengue. Respondents were asked that their answers reflected what they would do if they were the treating physician. We received responses from 306 physicians from 20 different countries. The heterogeneity of the responses highlights the variation in clinical practice and lack of an evidence base in this area and underscores the importance of prospective clinical trials to address this key question in the clinical management of patients with dengue.
Whitehorn, James; Roche, Rosmari Rodriguez; Guzman, Maria G.; Martinez, Eric; Villamil Gomez, Wilmar; Nainggolan, Leonard; Laksono, Ida Safitri; Mishra, Ajay; Lum, Lucy; Faiz, Abul; Sall, Amadou; Dawurung, Joshua; Borges, Alvaro; Leo, Yee-Sin; Blumberg, Lucille; Bausch, Daniel G.; Kroeger, Axel; Horstick, Olaf; Thwaites, Guy; Wertheim, Heiman; Larsson, Mattias; Hien, Tran Tinh; Peeling, Rosanna; Wills, Bridget; Simmons, Cameron; Farrar, Jeremy
NS5 methyltransferase (Mtase) has a crucial role in the replication of dengue virus. There are two active sites on NS5 Mtase i.e., SAM and RNA-cap binding sites. Inhibition of the NS5 Mtase activity is expected to prevent the propagation of dengue virus. This study was conducted to design cyclic peptide ligands as enzyme inhibitors of dengue virus NS5 Mtase through computational approach. Cyclopentapeptides were designed as ligand of SAM binding site as much as 1635 and 736 cyclopentpeptides were designed as ligand of RNA-cap binding site. Interaction between ligand and NS5 Mtase has been conducted on the Docking simulation. The result shows that cyclopentapeptide CTWYC was the best peptide candidate on SAM binding site, with estimated free binding energy -30.72 kca/mol. Cyclopentapeptide CYEFC was the best peptide on RNA-cap binding site with estimated free binding energy -22.89 kcal/mol. Both peptides did not have tendency toward toxicity properties. So it is expected that both CTWYC and CYEFC ligands could be used as a potential antiviral drug candidates, which can inhibit the SAM and RNA-cap binding sites of dengue virus NS5 Mtase.
Idrus, Syarifuddin; Tambunan, Usman Sumo Friend; Zubaidi, Ahmad Ardilla
In a step towards a tetravalent dengue virus subunit vaccine which is economical to produce, highly immunogenic and stable, a hybrid dengue virus envelope (E) protein molecule has been con- structed. It consists of 36 amino acids from the membrane protein, the N-terminal 288 amino acids of the dengue-2 virus E protein plus amino acids 289-424 of the dengue-3 virus
Helle Bielefeldt-Ohmann; David W. C. Beasley; David R. Fitzpatrick; John G. Aaskov
Implemented in 2009, the National Outbreak Reporting System provides surveillance for acute gastroenteritis outbreaks in the United States resulting from any transmission mode. Data from the first 2 years of surveillance highlight the predominant role of norovirus. The pathogen-specific transmission pathways and exposure settings identified can help inform prevention efforts. PMID:23876187
Hall, Aron J; Wikswo, Mary E; Manikonda, Karunya; Roberts, Virginia A; Yoder, Jonathan S; Gould, L Hannah
Implemented in 2009, the National Outbreak Reporting System provides surveillance for acute gastroenteritis outbreaks in the United States resulting from any transmission mode. Data from the first 2 years of surveillance highlight the predominant role of norovirus. The pathogen-specific transmission pathways and exposure settings identified can help inform prevention efforts.
Wikswo, Mary E.; Manikonda, Karunya; Roberts, Virginia A.; Yoder, Jonathan S.; Gould, L. Hannah
A waterborne disease outbreak associated with Salmonella typhimurium was identified in Gideon, Missouri (population 1104), a town in southeastern Missouri (USA) in December, 1993. It was estimated by the US Centers for Disease Control and Prevention (CDC) that approximately 44% of the city residents developed gastroenteritis during the outbreak. Data from the field investigation was used in a computer program
R. M. Clark; E. E. Geldreich; K. R. Fox; E. W. Rice; C. H. Johnson; J. A. Goodrich; J. A. Barnick; F. Abdesaken; J. E. Hill; F. J. Angulo
Surveillance of travel-acquired dengue could improve dengue risk estimation in countries without ability. Surveillance in the French army in 2010 to 2011 highlighted 330 dengue cases, mainly in French West Indies and Guiana: DENV-1 circulated in Guadeloupe, Martinique, French Guiana, New Caledonia, Djibouti; DENV-3 in Mayotte and Djibouti; and DENV-4 in French Guiana. PMID:23809078
de Laval, Franck; Dia, Aissata; Plumet, Sébastien; Decam, Christophe; Leparc Goffart, Isabelle; Deparis, Xavier
During an epidemic of dengue hemorrhagic fever on Koh Samui, Thailand, dengue viruses were recovered from 10 patients and 29 mosquito pools. All recovered strains were dengue type 4. Virus was recovered from both Aedes aegypti and Aedes albopictus under c...
P. K. Russell D. J. Gould T. M. Yuill A. Nisalak P. E. Winter
Dengue disease is an increasing global health problem that threatens one-third of the world's population. Despite decades of efforts, no licensed vaccine against dengue is available. With the aim to develop an affordable vaccine that could be used in young populations living in tropical areas, we evaluated a new strategy based on the expression of a minimal dengue antigen by
Samantha Brandler; Marianne Lucas-Hourani; Arnaud Moris; Marie-Pascale Frenkiel; Chantal Combredet; Michèle Février; Hugues Bedouelle; Olivier Schwartz; Philippe Desprès; Frédéric Tangy
Intelligent organizations (IO) represent a valuable tool to organize and guide dengue fever surveillance, prevention and control interventions. IO entail state of the art technology in managerial science to generate behavioral frameworks of organizational structures and policies. They present a systematic description of problems and construct computerized models to develop systemic thinking; they produce a shared vision and build progressive mental learning and advancement models. Also, IO promote team building and personal control skills. Scientific-technological advances have produced a wealth of information in medicine, with the corresponding growth of organizations and difficulty of responses because of sudden and incessant change. This new environment calls for the application of IO know-how. This article is oriented to prove the usefulness of the IO technology in the ordering and systematization of the reports about the medical sciences facts. Dengue was chosen to exemplify the use of IO technology as it represents an increasing health problem in America, as well as in Mexico; it is so complex that it can evolve to a more serious problem, besides it can be analyzed within a systemic method. PMID:8599151
Ortiz-Quesada, F; Méndez-Galván, J F; Ritchie-Dunham, J; Rosado-Muñoz, F J
During 2006–2007, a cohort of 144 confirmed dengue cases in Can Tho Province, Vietnam were compared with a matching set of 144 households that had no dengue cases. Approximately 6–9 months after sickness, there were no significant differences in terms of knowledge of the etiology of dengue, mosquito breeding habitats, and prevention measures in respondents from both sets of households. There was also no difference in the abundance of Aedes aegypti (Linn.) adults but the average numbers of late instar and pupal Ae. aegypti per household were greater in the negative control houses. Thus, the risk seemed to be no higher in case households, although it is conceivable that changes may have occurred in either group over the intervening period. The average cost for a dengue patient was 2,798,000 Vietnamese Dong (VND) (US$167.77), 2,154,000 VND for direct costs, and 644,000 VND for indirect costs. There was a 22% difference in cost for those with and without health insurance. In terms of impact on family economies, 47.2% had to borrow money for treatment, and after 6 months, 71.7% had not begun or had only managed part repayments. Approximately 72.9% indicated that the cost of supporting a dengue patient had impacted on the family economy, with the loss averaging 36% of the annual income in the lowest economic quartile.
Tam, Pham Thi; Dat, Nguyen Tan; Huu, Le Minh; Thi, Xuan Cuc Pham; Duc, Hoang Minh; Tu, Tran Cong; Kutcher, Simon; Ryan, Peter A.; Kay, Brian H.
There are 100 million cases of dengue infection, 500,000 cases of dengue hemorrhagic fever, and 25,000 deaths annually due to dengue worldwide. Gastrointestinal bleeding is the most common type of severe hemorrhage in dengue fever. However, there are no reports about the clinical applications of endoscopic therapy for upper gastroin- testinal bleeding (UGI) in dengue patients. From June 17, 2002
YI-CHUN CHIU; KENG-LIANG WU; CHUNG-HUANG KUO; TSUNG-HUI HU; YEH-PIN CHOU; SENG-KEE CHUAH; CHUNG-MOU KUO; KWONG-MING KEE; CHI-SIN CHANGCHIEN; JIEN-WEI LIU; KING-WAH CHIU
Background: The spectrum of liver dysfunction in children with dengue infection is wide and has been associated with disease severity. Aims: This study was undertaken to estimate the range of hepatic involvement in dengue infection in children. Materials and Methods: This study assessed the biochemical and clinical profile of hepatic involvement by dengue virus in 120 children with serologically positive dengue fever (DF), aged 2 months to 14 years. Results: All cases were grouped into DF without warning signs (Group 1), DF with warning signs (Group 2) and severe dengue (Group 3) according to revised World Health Organization 2009 criteria. The spectrum of hepatic manifestations included hepatomegaly (80.8%), hepatic tenderness (46.3%), jaundice (60%), raised aspartate transaminase (AST), alanine transaminase (ALT) and prolonged prothrombin time (41.7%) and reduced serum albumin (56%). Conclusions: Hepatic dysfunction was observed more in Groups 2 and 3. There was 84.4% and 93.75% ALT and AST elevation respectively in Group 2 and 94.5% and 95.9% ALT and AST elevation respectively in Group 3 and fulminant hepatic failure was observed in Group 3. Therefore in a child with fever, jaundice, hepatomegaly and altered liver function tests, the diagnosis of dengue infection should be strongly considered in areas where dengue infection is endemic.
Roy, Amrita; Sarkar, Debalina; Chakraborty, Sohini; Chaudhuri, Jasodhara; Ghosh, Pramit; Chakraborty, Swapna
Dengue fever, a mosquito-borne flavivirus infection, is endemic in Southeast Asia. Currently, incidences have been increasing among adults. There have been no published reports of dengue fever from Iran. Widespread connection between different countries may predispose them for acquisition of infection. The patient was a 58-year-old Iranian woman with acute unexplained high-grade fever for 4 days, associated with skin rash, after returning from Southeast Asia. CBC showed WBC = 1600/mm(3) and platelet count 99,000/mm(3). The patient also had hematuria. ELISA immunoglobulin M (IgM) antibodies to dengue and serum RT-PCR for dengue virus was positive. The patient managed with conservative treatment and due to good general condition and improvement specific antiviral treatment was not started. She became afebrile at the 3(rd) day of hospitalization and discharged with good general condition on fourth day. She was afebrile after two weeks follow-up. Dengue fever has been increasing among adults. It should be suspected, when a patient presents with acute febrile illness and skin rashes returning from endemic region. Conservative treatment may be conducted in uncomplicated cases. PMID:24130951
Mardani, Masoud; Abbasi, Farhad; Aghahasani, Morteza; Ghavam, Babak
The incidence of dengue increased sharply in Martinique from the end of 1995 into 1996. Virological tests performed jointly on 36 serum samples by the Pasteur Institute in French Guyana and the Center for Disease Control in Puerto Rico led to identification of serogroups 1, 2, and 4 for six dengue virus. Between January 1995 and December 1996, the Departmental Hygiene Laboratory of Martinique carried out screening tests to detect specific IgM by the immunocapture method (MAC ELISA) in patients with suspected dengue. Results were positive in 701 of the 2,143 patients tested (32.7%). Symptoms were studied in 421 of these positive cases. The most frequent presentation was a flu-like syndrome with hyperalgia. Nausea, vomiting, joint pain, and retroocular pain were frequent. At least one clinical sign of coagulation disturbance was noted in 83 patients (19.7%). Dengue hemorrhagic syndrome was diagnosed according to the criteria of the World Health Organization in six patients including one who developed circulatory collapse and died. This fatality was the first to be reported in Martinique. The incidence of typical dengue as well as of the hemorrhagic form is probably underestimated in Martinique because specific serological tests are not routinely requested and application of WHO criteria for diagnosis of hemorrhagic forms is often impractical. PMID:9791593
Villeneuve, L; Mansuy, J M; Magnaval, J F; Schlegel, L
Dengue fever is a noncontagious infectious disease caused by dengue virus (DENV). DENV belongs to the family Flaviviridae, genus Flavivirus, and is classified into four antigenically distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The number of nations and people affected has increased steadily and today is considered the most widely spread arbovirus (arthropod-borne viral disease) in the world. The absence of an appropriate animal model for studying the disease has hindered the understanding of dengue pathogenesis. In our study, we have found that immunocompetent C57BL/6 mice infected intraperitoneally with DENV-1 presented some signs of dengue disease such as thrombocytopenia, spleen hemorrhage, liver damage, and increase in production of IFN? and TNF? cytokines. Moreover, the animals became viremic and the virus was detected in several organs by real-time RT-PCR. Thus, this animal model could be used to study mechanism of dengue virus infection, to test antiviral drugs, as well as to evaluate candidate vaccines. PMID:22666132
Gonçalves, Denise; de Queiroz Prado, Rafael; Almeida Xavier, Eric; Cristina de Oliveira, Natália; da Matta Guedes, Paulo Marcos; da Silva, João Santana; Moraes Figueiredo, Luiz Tadeu; Aquino, Victor Hugo
Dengue fever, a mosquito-borne flavivirus infection, is endemic in Southeast Asia. Currently, incidences have been increasing among adults. There have been no published reports of dengue fever from Iran. Widespread connection between different countries may predispose them for acquisition of infection. The patient was a 58-year-old Iranian woman with acute unexplained high-grade fever for 4 days, associated with skin rash, after returning from Southeast Asia. CBC showed WBC = 1600/mm3 and platelet count 99,000/mm3. The patient also had hematuria. ELISA immunoglobulin M (IgM) antibodies to dengue and serum RT-PCR for dengue virus was positive. The patient managed with conservative treatment and due to good general condition and improvement specific antiviral treatment was not started. She became afebrile at the 3rd day of hospitalization and discharged with good general condition on fourth day. She was afebrile after two weeks follow-up. Dengue fever has been increasing among adults. It should be suspected, when a patient presents with acute febrile illness and skin rashes returning from endemic region. Conservative treatment may be conducted in uncomplicated cases.
Mardani, Masoud; Abbasi, Farhad; Aghahasani, Morteza; Ghavam, Babak
... collected during the outbreak, ill persons answered questions about foods consumed and other exposures during the week before becoming ill. ... More results from www.fda.gov/food/recalls,%20outbreaks%20&%20emergencies/outbreaks
In August 2012, FDA warned consumers against eating mangoes from Agricola Daniella. Read details of the outbreak and the response to it. More results from www.fda.gov/food/recalls,%20outbreaks%20&%20emergencies/outbreaks
All human Ebola virus outbreaks during 2001–2003 in the forest zone between Gabon and Republic of Congo resulted from handling infected wild animal carcasses. After the first outbreak, we created an Animal Mortality Monitoring Network in collaboration with the Gabonese and Congolese Ministries of Forestry and Environment and wildlife organizations (Wildlife Conservation Society and Programme de Conservation et Utilisation Rationnelle des Ecosystèmes Forestiers en Afrique Centrale) to predict and possibly prevent human Ebola outbreaks. Since August 2001, 98 wild animal carcasses have been recovered by the network, including 65 great apes. Analysis of 21 carcasses found that 10 gorillas, 3 chimpanzees, and 1 duiker tested positive for Ebola virus. Wild animal outbreaks began before each of the 5 human Ebola outbreaks. Twice we alerted the health authorities to an imminent risk for human outbreaks, weeks before they occurred.
Froment, Jean-Marc; Bermejo, Magdalena; Kilbourn, Annelisa; Karesh, William; Reed, Patricia; Kumulungui, Brice; Yaba, Philippe; Delicat, Andre; Rollin, Pierre E.; Leroy, Eric M.
|Twenty outbreaks of foodborne illness in schools were reported to the Centers for Disease Control and Prevention (CDC) during 1997; however, only 8 cases were associated with food served in the school meal programs. Preliminary findings identified nine outbreaks in 1998, affecting an estimated 1,609 individuals. CDC notes that such outbreaks are…
Robertson, Robert E.
We still have an incomplete understanding of both immunoprotection and immunopathogenesis mechanisms in dengue. Proper balance among the components of the immune response plays an important role in protection as well as in pathogenesis because these impact clinical outcomes and severity of dengue cases. In this article, we review the elements of the immune response that participate in DENV infections, and we contrast the levels of immune effectors in both classic dengue fever and the severe dengue fever cases. We also emphasize the components frequently related to the immunopathogenesis in dengue. It is clear that several effectors are increased or dysregulated in the severe cases. Finally, the global mechanism that contributes to the subversion of the immune system in dengue hemorrhagic fever or dengue shock syndrome still requires complete elucidation. PMID:24108339
Castro-Mussot, María Eugenia; Machain-Williams, Carlos; Loroño-Pino, María Alba; Salazar, Ma Isabel
Dengue is an important global public health problem. The World Health Organization estimates that 2/5 of entire world population are in risk of dengue infection. Almost 50 millions cases occur annually, with at least 20 thousand deaths. The etiological agent of this acute febrile disease is a single-strand positive-sense RNA virus of Flavivirus genus. It is an arboviral disease transmitted by Aedes sp. mosquitoes (Aedes aegypti and A. albopictus). Most infected individuals present asymptomatic infection, but some may develop clinical signs. Therefore, a wide spectrum of illness can be observed, ranging from unapparent, mild disease, called dengue fever, to a severe and occasionally fatal dengue hemorrhagic fever/dengue shock syndrome. Currently, neurological manifestations related to dengue infections are increasingly been observed and appears as a challenge for medical practice. In this study the neurological complications of dengue infection will be reviewed, focusing a better understanding of the disease for the clinical practice. PMID:24141501
Puccioni-Sohler, Marzia; Rosadas, Carolina; Cabral-Castro, Mauro Jorge
Dengue viruses are members of the Flaviviridae, transmitted principally in a cycle involving humans and mosquito vectors. In the last 20 years the incidence of dengue fever epidemics has increased and hyperendemic transmission has been established over a geographically expanding area. A severe form, dengue hemorrhagic fever (DHF), is an immunopathologic disease occurring in persons who experience sequential dengue infections. The risk of sequential infections, and consequently the incidence of DHF, has risen dramatically, first in Asia and now in the Americas. At the root of the emergence of dengue as a major health problem are changes in human demography and behavior, leading to unchecked populations of and increased exposure to the principal domestic mosquito vector, Aedes aegypti. Virus-specified factors also influence the epidemiology of dengue. Speculations on future events in the epidemiology, evolution, and biological expression of dengue are presented. Images
Monath, T P
The Water-associated Disease Index (WADI) was developed to identify and visualize vulnerability to different water-associated diseases by integrating a range of social and biophysical determinants in map format. In this study vulnerability is used to encompass conditions of exposure, susceptibility, and differential coping capacity to a water-associated health hazard. By assessing these conditions, the tool is designed to provide stakeholders with an integrated and long-term understanding of subnational vulnerabilities to water-associated disease and contribute to intervention strategies to reduce the burden of illness. The objective of this paper is to describe and validate the WADI tool by applying it to dengue. A systemic ecohealth framework that considers links between people, the environment and health was applied to identify secondary datasets, populating the index with components including climate conditions, land cover, education status and water use practices. Data were aggregated to create composite indicators of exposure and of susceptibility in a Geographic Information System (GIS). These indicators were weighted by their contribution to dengue vulnerability, and the output consisted of an overall index visualized in map format. The WADI was validated in this Malaysia case study, demonstrating a significant association with dengue rates at a sub-national level, and illustrating a range of factors that drive vulnerability to the disease within the country. The index output indicated high vulnerability to dengue in urban areas, especially in the capital Kuala Lumpur and surrounding region. However, in other regions, vulnerability to dengue varied throughout the year due to the influence of seasonal climate conditions, such as monsoon patterns. The WADI tool complements early warning models for water-associated disease by providing upstream information for planning prevention and control approaches, which increasingly require a comprehensive and geographically broad understanding of vulnerability for implementation. PMID:23667642
Dickin, Sarah K; Schuster-Wallace, Corinne J; Elliott, Susan J
Background Dengue virus-host cell interaction initiates when the virus binds to the attachment receptors followed by endocytic internalization of the virus particle. Successful entry into the cell is necessary for infection initiation. Currently, there is no protective vaccine or antiviral treatment for dengue infection. Targeting the viral entry pathway has become an attractive therapeutic strategy to block infection. This study aimed to investigate the effect of silencing the GRP78 and clathrin-mediated endocytosis on dengue virus entry and multiplication into HepG2 cells. Methodology/Principal Findings HepG2 cells were transfected using specific siRNAs to silence the cellular surface receptor (GRP78) and clathrin-mediated endocytosis pathway. Gene expression analysis showed a marked down-regulation of the targeted genes (87.2%, 90.3%, and 87.8% for GRP78, CLTC, and DNM2 respectively) in transfected HepG2 cells when measured by RT-qPCR. Intracellular and extracellular viral RNA loads were quantified by RT-qPCR to investigate the effect of silencing the attachment receptor and clathrin-mediated endocytosis on dengue virus entry. Silenced cells showed a significant reduction of intracellular (92.4%) and extracellular viral RNA load (71.4%) compared to non-silenced cells. Flow cytometry analysis showed a marked reduction of infected cells (89.7%) in silenced HepG2 cells compared to non-silenced cells. Furthermore, the ability to generate infectious virions using the plaque assay was reduced 1.07 log in silenced HepG2 cells. Conclusions/Significance Silencing the attachment receptor and clathrin-mediated endocytosis using siRNA could inhibit dengue virus entry and multiplication into HepG2 cells. This leads to reduction of infected cells as well as the viral load, which might function as a unique and promising therapeutic agent for attenuating dengue infection and prevent the development of dengue fever to the severe life-threatening DHF or DSS. Furthermore, a decrease of viremia in humans can result in the reduction of infected vectors and thus, halt of the transmission cycle.
Alhoot, Mohammed Abdelfatah; Wang, Seok Mui; Sekaran, Shamala Devi
Nipah virus, a novel paramyxovirus, closely related to Hendra virus emerged in northern part of Peninsular Malaysia in 1998. The virus caused an outbreak of severe febrile encephalitis in humans with a high mortality rate, whereas, in pigs, encephalitis and respiratory diseases but with a relatively low mortality rate. The outbreak subsequently spread to various regions of the country and
Kaw Bing Chua
Background Dengue is the most prevalent mosquito borne infection worldwide. Vertical transmissions after maternal dengue infection to the fetus and pregnancy losses in relation to dengue illness have been reported. The relationship of dengue to miscarriage is not known. Method We aimed to establish the relationship of recent dengue infection and miscarriage. Women who presented with miscarriage (up to 22 weeks gestation) to our hospital were approached to participate in the study. For each case of miscarriage, we recruited 3 controls with viable pregnancies at a similar gestation. A brief questionnaire on recent febrile illness and prior dengue infection was answered. Blood was drawn from participants, processed and the frozen serum was stored. Stored sera were thawed and then tested in batches with dengue specific IgM capture ELISA, dengue non-structural protein 1 (NS1) antigen and dengue specific IgG ELISA tests. Controls remained in the analysis if their pregnancies continued beyond 22 weeks gestation. Tests were run on 116 case and 341 control sera. One case (a misdiagnosed viable early pregnancy) plus 45 controls (39 lost to follow up and six subsequent late miscarriages) were excluded from analysis. Findings Dengue specific IgM or dengue NS1 antigen (indicating recent dengue infection) was positive in 6/115 (5·2%) cases and 5/296 (1·7%) controls RR 3·1 (95% CI 1·0–10) P?=?0·047. Maternal age, gestational age, parity and ethnicity were dissimilar between cases and controls. After adjustments for these factors, recent dengue infection remained significantly more frequently detected in cases than controls (AOR 4·2 95% CI 1·2–14 P?=?0·023). Interpretation Recent dengue infections were more frequently detected in women presenting with miscarriage than in controls whose pregnancies were viable. After adjustments for confounders, the positive association remained.
Tan, Peng Chiong; Soe, May Zaw; Si Lay, Khaing; Wang, Seok Mui; Sekaran, Shamala Devi; Omar, Siti Zawiah
Research has demonstrated that cholera epidemics in Bangladesh occur seasonally. This bimodal outbreak pattern closely follows times when large monsoon events are most frequent (spring and fall). While these patterns are presented in regional data, this knowledge alone cannot forecast the severity and location of cholera outbreaks until a monsoon event occurs, or an outbreak is reported. Therefore, there can only be reactive responses to cholera outbreaks. A heightened understanding of the link between environmental factors and outbreak occurrence will greatly enhance disease management capabilities. A predictive tool capable of giving an advanced warning of the environmental hazards that lead to location specific outbreaks allows for proactive and preventative responses, minimizing negative effects. A specific goal of this research was to relate latitude-longitude data with existing points associated with V. cholerae human case data collected from four cities in Bangladesh. Remotely sensed products were used to better understand the correlation between human outbreak occurrences, chlorophyll-a estimates, sea surface temperature (SST), and rainfall. Using MODIS, SeaWiFS, and TRMM satellite data, a gridded regional image was developed. Correlation analyses of the data were studied within the context of geographically diverse locations for the four cities of interest. Seasonal relationships were found between the cholera case data and all three of the chosen remotely sensed parameters. The strongest correlation found was between chlorophyll-a concentrations and reported human cases. The primary deliverable of this project was the production of an interactive Google Earth base map for use in a pilot design study that will lead to the development of applications to connect earth science products with water and health studies. The base map, with its inherent value of merging remotely sensed data with in situ observation points, can be used as a basis for constructing better models of disease outbreaks. This effort will build upon current research at University of Maryland, College Park, which focuses on the impacts of climate on both water and health.
Stack, D.; Sandborn, A.; Widmeyer, P. A.; Escobar, V. M.
To strengthen active dengue surveillance in Saint Martin and Saint Barthélemy, two French Caribbean islands, we evaluated the epidemiological usefulness of collecting blood samples from NS1-positive dengue patients on filter paper to identify the dengue serotypes circulating in these regions during a 27-month period. This approach allowed dengue serotypes to be identified by reverse transcriptase-polymerase chain reaction in 90.1% of the total set of 666 samples analyzed and, in 95.5% of the samples collected during the acute phase of the disease. This prospective virological surveillance using blood samples absorbed onto filter paper, which were stored at 4°C and shipped at ambient temperature to a specialized laboratory for analysis, allowed us to avoid the logistic and financial costs associated with shipping frozen venous blood samples. This surveillance system offers a low-cost alternative for reinforcing dengue prevention in areas where specialized laboratories do not exist, notably by facilitating the early detection of potentially new dengue serotypes.
Matheus, Severine; Chappert, Jean-Loup; Cassadou, Sylvie; Berger, Franck; Labeau, Bhetty; Bremand, Laetitia; Winicki, Alain; Huc-Anais, Patricia; Quenel, Philippe; Dussart, Philippe
The purpose of this study was to examine the relationship between Aedes aegypti egg and adult density indices, dengue fever and climate in Mirassol, state of São Paulo, Brazil, between November 2004-November 2005. Weekly collections of adults and eggs were made using, respectively, manual aspirators and oviposition traps that produced four entomological indices (positivity and average of females and eggs). Weekly incidence coefficients were calculated based on dengue cases. Each week, the data obtained from entomological indices were related to each other, dengue, and climate variables. The first index to show an association with dengue transmission was the female average, followed by female positivity and egg average. Egg positivity did not show a relationship with risk for dengue, but was sensitive to identifying the presence of the vector, principally in dry seasons. The relationship between climatic factors, the vector and the disease found in this study can be widely employed in planning and undertaking dengue surveillance and control activities, but it is a tool that has not been considered by the authorities responsible for controlling the disease. In fact, this relationship permits the use of information about climate for early detection of epidemics and for establishing more effective prevention strategies than currently exist. PMID:18949325
Dibo, Margareth Regina; Chierotti, Ana Patricia; Ferrari, Mariana Silveira; Mendonça, Adriano Luis; Chiaravalloti Neto, Francisco
During 2010, an outbreak of West Nile virus infection occurred in Greece. A total of 197 patients with neuroinvasive disease were reported, of whom 33 (17%) died. Advanced age and a history of heart disease were independently associated with death, emphasizing the need for prevention of this infection in persons with these risk factors.
Papa, Anna; Theocharopoulos, George; Dougas, Georgios; Athanasiou, Maria; Detsis, Marios; Baka, Agoritsa; Lytras, Theodoros; Mellou, Kassiani; Bonovas, Stefanos; Panagiotopoulos, Takis
An infant with diarrhea attended a community playgroup. In the subsequent 48 hours, 6 of the 7 mothers and children reported gastroenteritis; fecal specimens from 5 persons tested positive for norovirus, with identical sequences. No breach of hygiene or contact with fecal matter was identified. Excluding the child with gastroenteritis from the playgroup could have prevented this outbreak. PMID:15933572
Isakbaeva, Elmira T; Bulens, Sandra N; Beard, R Suzanne; Adams, Susan; Monroe, Stephan S; Chaves, Sandra S; Widdowson, Marc-Alain; Glass, Roger I
In the second half of the twentieth century dengue spread throughout the tropics, threatening the health of a third of the world's population. Dengue viruses cause 50-100 million cases of acute febrile disease every year, including more than 500,000 reported cases of the severe forms of the disease--dengue haemorrhagic fever and dengue shock syndrome. Attempts to create conventional vaccines have been hampered by the lack of suitable experimental models, the need to provide protection against all four serotypes simultaneously and the possible involvement of virus-specific immune responses in severe disease. The current understanding of dengue pathogenesis is outlined in this review, with special emphasis on the role of the immune response. The suspected involvement of the immune system in increased disease severity and vascular damage has raised concerns about every vaccine design strategy proposed so far. Clearly more research is needed on understanding the correlates of protection and mechanisms of pathogenesis. There is, however, an urgent need to provide a solution to the escalating global public health problems caused by dengue infections. Better disease management, vector control and improved public health measures will help reduce the current disease burden, but a safe and effective vaccine is probably the only long-term solution. Although concerns have been raised about the possible safety and efficacy of both conventional and novel vaccine technologies, the situation is now so acute that it is not possible to wait for the perfect vaccine. Consequently the careful and thorough evaluation of several of the current candidate vaccines may be the best approach to halting the spread of disease.
Stephenson, John R.
Dengue is considered an emerging disease with an increasing prevalence especially in South America. In 2002, an epidemic of classic Dengue (DENV-1) occurred unexpectedly on Easter Island, where it had never been detected before. It reappeared in 2006-2007 and 2008, 2009 and 2011. The aim of this study was to estimate the most relevant parameters of the epidemiological dynamics of transmission of Dengue on Easter Island and to model the dynamics since 2002, comparing the predictions with the actual situation observed. Of the total cases, 52.27% were females and 47.73% men. The average age of infection was 31.38 ± 18.37 years, similar in men and women. We estimated the reproductive number R0 = 3.005 with an IC0,95 = [1.92, 4.61]. The inter-epidemic period reached an estimated T = 5.20 to 6.8 years. The case simulation showed recurrent epidemics with decreasing magnitude (damped oscillations), which is a known phenomenon in models of dengue and malaria. There was good qualitative fit to the epidemiological dynamics from 2002 onwards. It accurately predicted the rise in cases between 2006 and 2011. The predicted number of cases during the 2002 epidemic is greater than the confirmed cases and the predicted epidemic was faster than notified cases. Interepidemic period in the simulation was 6.72 years between 2002 and 2008 and 4.68 years between 2008 and 2013. From the theoretical perspective, the first epidemic had affected 94% of the population (approximately 3500 cases), but 639 were reported suggesting underreporting and a lot of sub-clinical cases occurred. Future epidemic of decreasing size are expected, although the main danger are epidemics of hemorrhagic dengue fever resulting from the introduction of different dengue virus serotypes. PMID:23096537
Canals, Mauricio; González, Christian; Canals, Andrea; Figueroa, Daniela
Dengue is the most important arboviral disease worldwide. We report the complete genome sequence of a dengue virus serotype 4, genotype II strain isolated in 2010 from a patient with classical dengue fever in Boa Vista, Roraima, Brazil.
Souza, Victor C.; Silva, George A. V.; Maito, Rodrigo M.; Granja, Fabiana; Siqueira, Thalita; Acosta, Pablo O. A.
Dengue is the most important arboviral disease worldwide. We report the complete genome sequence of a dengue virus serotype 4, genotype II strain isolated in 2010 from a patient with classical dengue fever in Boa Vista, Roraima, Brazil. PMID:22247521
Naveca, Felipe G; Souza, Victor C; Silva, George A V; Maito, Rodrigo M; Granja, Fabiana; Siqueira, Thalita; Acosta, Pablo O A
We report a case of nephrotic range proteinuria with 24-hour urine protein level of 335.7 mg/kg/day which developed following dengue hemorrhagic fever. Due to prolonged hypoalbuminemia from renal loss, right pleural effusion persisted and required pleuracentesis. The patient did not have classical nephrotic syndrome. The proteinuria improved without specific treatment. A renal biopsy was not performed due to self-resolution of the proteinuria and azotemia. Heavy proteinuria is not a typical characteristic of dengue virus infection, therefore the pathophysiology of this nephropathy has not been well described to date. PMID:21706936
Hutspardol, Sakara; Prommalikit, Olarn; Upiya, Nuttaphol; Chataroopwijit, Jintana; Khemakanok, Khemika; Assadamongkol, Kesara
... FAQ: Non-U.S. Visitors to Yosemite Outbreak of Hantavirus Infection in Yosemite National Park As of November ... Añadir en... Favorites Delicious Digg Google Bookmarks Preventing Hantavirus Pulmonary Syndrome (HPS) Eliminate or minimize contact with ...
6%, 21%) of the total cases; 2) closing the drinking-water plant prevented 19% (95% confidence interval: 17%, 21%) of the additional cases of disease that occurred compared with the scenario in which the plant had not been closed, a result primarily driven by conferred immunity that resulted in depletion of the susceptible population; and 3) the outbreak was caused by
Joseph N. S. Eisenberg; Xiudong Lei; Alan H. Hubbard; M. Alan Brookhart; John M. Colford
Military operations are conducted in a variety of settings. Some settings provide significant U.S. resources for preventive, primary, urgent, and emergency or trauma care. Other operations consist of small numbers of personnel relying on limited internal, improvised, and/or host nation resources. Special Forces often conduct their missions in rural, austere, and remote settings with a small "medical footprint." Often the supported government has difficulty providing essential services, including medical care. To address this, U.S. Special Forces select and train highly motivated individuals to perform medical duties in an exceptionally austere environment devoid of resources. This case highlights those services and the medical decision-making process required to provide medical care to approach the standard of care in the United States. In this case, the affected individual had dengue fever. PMID:16997781
Taylor, Shawn F; Taylor, Charles L
Dengue virus (DENV) infections are expanding worldwide and, because of the lack of a vaccine, the search for antiviral products is imperative. Four serotypes of DENV are described and they all cause a similar disease outcome. It would be interesting to develop an antiviral product that can interact with all four serotypes, prevent host cell infection and subsequent immune activation. DENV entry is thus an interesting target for antiviral therapy. DENV enters the host cell through receptor-mediated endocytosis. Several cellular receptors have been proposed, and DC-SIGN, present on dendritic cells, is considered as the most important DENV receptor until now. Because DENV entry is a target for antiviral therapy, various classes of compounds have been investigated to inhibit this process. In this paper, an overview is given of all the putative DENV receptors, and the most promising DENV entry inhibitors are discussed.
Alen, Marijke M. F.; Schols, Dominique
This study assessed the current situation and trends of dengue fever\\/dengue haemorrhagic fever (DF\\/DHF) in Myanmar and its states\\/divisions. It made forecasts from the epidemiological standpoint and also attempted a comparison with Thailand. Between 1991 and 2001, the distribution of DF\\/DHF showed upward trends with cyclical pattern and seasonal variation. Heterogenous distribution of DF\\/DHF in Myanmar was evident. According to
Dengue fever\\/dengue haemorrhagic fever (DF\\/DHF) is the most important emerging viral disease affecting nearly half of the world's population. It is estimated that there are between 50 to 100 million cases of DF and about 500 000 cases of DHF which require hospitalization every year. In the WHO South-East Asia Region, over the past 15 years, DF\\/DHF has become a
Chusak Prasittisuk; A. G. Andjaparidze; Vijay Kumar
To characterize the dengue epidemic that recently occurred in Malaysia, we sequenced cDNAs from nine 1993-1994 dengue virus type-3 (DEN-3) isolates in Malaysia (DEN-3 was the most common type in Malaysia during this period). Nucleic acid sequences (720 nucleotides in length) from the nine isolates, encompassing the precursor of membrane protein (preM) and membrane (M) protein genes and part of
NOBUYOSHI KOBAYASHI; RAVINDRAN THAYAN; CHIE SUGIMOTO; KAZUMASA ODA; ZAINAH SAAT; BALASUBRAMANIAM VIJAYAMALAR; MANGALAM SINNIAH; AKIRA IGARASHI
Summary. ?Dengue is an acute viral disease transmitted by the Aedesaegypti mosquito which is present in most tropical urban areas of the world. There are four antigenically distinct serotypes, designated\\u000a dengue-1 (DEN-1), dengue-2 (DEN-2), dengue-3 (DEN-3) and dengue-4 virus (DEN-4). In this study, we determined the serotypes\\u000a of dengue viruses isolated in Guatemala in 1995–1998, and found that DEN-3 viruses appeared
S. Usuku; L. Castillo; C. Sugimoto; Y. Noguchi; Y. Yogo; N. Kobayashi
Background: Despite the seriousness of dengue-related disease, with an estimated 50-100 million cases of dengue fever and 250,000-500,000 cases of dengue hemorrhagic fever\\/dengue shock syndrome each year, a clear understanding of dengue pathogenesis remains elusive. Because of the lack of a disease model in animals and the complex immune interaction in dengue infection, the study of host response and immunopathogenesis
Joshua Fink; Feng Gu; Ling Ling; Thomas Tolfvenstam; Farzad Olfat; Keh Chuang Chin; Pauline Aw; Joshy George; Vladimir A. Kuznetsov; Mark Schreiber; Subhash G. Vasudevan; Martin L. Hibberd
In Myanmar, dengue fever (DF)/dengue hemorrhagic fever (DHF) is one of the leading causes of morbidity and mortality among children. From Pyinmana Hospital in 2004 and Mandalay Children Hospital in 2006, 160 patients diagnosed clinically to have DHF/dengue shock syndrome (DSS) were examined for immunoglobulin M (IgM) and IgG levels. A focus reduction neutralization test was also used to determine primary or secondary dengue virus (DENV) infection. By using IgM-capture ELISA, 139 cases were confirmed as DENV infections. Of these IgM-positives, 94 samples were collected 7-24 days from the onset of illness, to which 13 (14%) and 81 (86%) were determined to be primary and secondary DENV infections, respectively. The 13 primary DENV infection cases were spread among the various severity groups (DHF grade I-IV and DSS) and represented age groups ranging from <1 year of age to 9 years of age. The patients in these primary infection cases showed a remarkably high IgM with a low IgG titer response compared with the secondary infection cases. No significant differences were observed in IgG titers with clinical severity. The data obtained in this study suggest that primary DENV infection cases exist certainly among DHF/DSS cases in Myanmar, and that additional mechanism(s) aside from the antibody-dependent enhancement mechanism could have influenced the clinical severity in DHF/DSS cases. PMID:23595687
Ngwe Tun, Mya Myat; Thant, Kyaw Zin; Inoue, Shingo; Kurosawa, Yae; Lwin, Yee Yee; Lin, Sanda; Aye, Kay Thi; Thet Khin, Pe; Myint, Tin; Htwe, Khin; Mapua, Cynthia A; Natividad, Filipinas F; Hirayama, Kenji; Morita, Kouichi
A total of 136 matched serum and urine samples obtained from 55 patients with dengue infection and 30 other febrile illnesses were assayed for dengue nonstructural protein 1 (NS1) antigen. The urine NS1 ELISA was positive in patients with dengue fever (68.4%) and dengue hemorrhagic fever (63.9%), whereas the strip method showed a lower positive rate. PMID:21996098
Chuansumrit, Ampaiwan; Chaiyaratana, Wathanee; Tangnararatchakit, Kanchana; Yoksan, Sutee; Flamand, Marie; Sakuntabhai, Anavaj
A dengue-2 epidemic causing dengue hemorrhagic fever (DHF) occurred in the contiguous border cities of Matamoros, Tamaulipas (Mexico), and Brownsville, TX, in 2005. In December, we conducted a household-based epidemiologic survey to determine the incidence and seroprevalence of dengue infection among Matamoros and Brownsville residents and to identify risk factors associated with infection. Antibodies to dengue were measured in 273
Mary M. Ramos; Hamish Mohammed; Mary H. Hayden; Jose Luis Robles Lopez; Marta Fournier; Roy Burton; Joan M. Brunkard; Luis Anaya-Lopez; Allison Abell Banicki; Pablo Kuri Morales; Brian Smith; Jorge L. Muñoz; Stephen H. Waterman
Background Leptospirosis is an emerging zoonosis that is often under-recognized in children and commonly confused with dengue in tropical settings. An enhanced ability to distinguish leptospirosis from dengue in children would guide clinicians and public health personnel in the appropriate use of limited healthcare resources. Methodology/Principal Findings We conducted a prospective, hospital-based, study of children with acute febrile illnesses and dengue in Thailand. Among the children without dengue, we identified those with leptospirosis using anti-leptospira IgM and microscopic agglutination titers in paired acute and convalescent blood samples. We then performed a case-control comparison of symptoms, signs, and clinical laboratory values between children with leptospirosis and dengue. In a semi-rural region of Thailand, leptospirosis accounted for 19% of the non-dengue acute febrile illnesses among children presenting during the rainy season. None of the children with leptospirosis were correctly diagnosed at the time of hospital discharge, and one third (33%) were erroneously diagnosed as dengue or scrub typhus. A predictive model to distinguish pediatric leptospirosis from dengue was generated using three variables: the absolute neutrophil count, plasma albumin, and aspartate aminotransferase levels in the first 72 hours of illness. Conclusions/Significance Unrecognized leptospirosis can be a significant cause of “dengue-like” febrile illness in children. Increased awareness of pediatric leptospirosis, and an enhanced ability to discriminate between leptospirosis and dengue early in illness, will help guide the appropriate use of healthcare resources in often resource-limited settings.
Libraty, Daniel H.; Myint, Khin S. A.; Murray, Clinton K.; Gibbons, Robert V.; Mammen, Mammen P.; Endy, Timothy P.; Li, Wenjun; Vaughn, David W.; Nisalak, Ananda; Kalayanarooj, Siripen; Hospenthal, Duane R.; Green, Sharone; Rothman, Alan L.; Ennis, Francis A.
After the introduction of measles vaccine in the United States in 1963 the reported incidence of measles (rubeola) decreased substantially. The disease, however, has not been eliminated. Since 1983, when the lowest number of cases was reported, slight increases in incidence have been observed. Outbreaks are occurring among previously immunized school- and college-age children and unimmunized preschool children and infants. This article describes measles occurrence, transmission, diagnosis, development of measles immunity, the 1989 Centers for Disease Control recommendations for immunization, and implications for health care providers for preventing measles outbreaks. PMID:2547055
Grimes, D E; Woolbert, L F
Objective To predict the performance of outbreak detection algorithms under different circumstances which will guide the method selection and algorithm configuration in surveillance systems, to characterize the dependence of the performance of detection algorithms on the type and severity of outbreak, to develop quantitative evidence about determinants of detection performance. Introduction The choice of outbreak detection algorithm and its configuration can result in important variations in the performance of public health surveillance systems. Our work aims to characterize the performance of detectors based on outbreak types. We are using Bayesian networks (BN) to model the relationships between determinants of outbreak detection and the detection performance based on a significant study on simulated data. Methods The simulated surveillance data that we used was generated by Surveillance Lab of McGill University using Simulation Analysis Platform  considering surveillance in an urban area to detect waterborne outbreaks due to the failure of a water treatment plant. We focus on predicting the performance of the C-family of algorithms, because they are widely used, state-of-art outbreak detection algorithms . We investigate the influence of algorithm characteristics and outbreak characteristics in determining outbreak detection performance. The C1, C2, and C3 are distinguished by the configuration of 2 parameters,the guardband and memory. Generally, gradually increasing outbreaks can bias the test statistic upward, so the detection algorithm will fail to flag the outbreak. To avoid this situation, the C2 and C3 use a 2-day gap, guardband, between the baseline interval and the test interval. The C3 includes 2 recent observations, called memory, in the computation of the test statistic. The W2 algorithm is a modified version of the C2 which takes weekly patterns of surveillance time series into account . In the W2, the baseline data is stratified to 2 distinct baselines: one for weekdays, the other for weekends. The W3 includes 2 recent observations of each baseline while calculating the test statistic in the corresponding baseline. We ran the C1, C2, C3, W2, and W3 on 18k simulated time series and measured the sensitivity and specificity of detection. Then we created the training data set of 5400000 instances. Each instance was the result of performance evaluation of an outbreak detection algorithm with a specific setting of parameters. In order to investigate the determinants of detection performance and reveal their effects quantitatively, we used BN to predict the performance based on algorithm characteristics and outbreak characteristics. Results We developed 2 BN models in the Weka machine learning software  using 5-fold cross-validation. The first BN determines the effect of the guardband, memory, alerting threshold, and the weekly pattern indicator (0 for C-algorithms, 1 for W-algorithms) and outbreak characteristics (contamination level and duration) on the sensitivity of detection. The value of sensitivity was mapped to 4 classes: (0, 0.3], (0.3, 0.6], (0.6, 0.9], (0.9, 1]. The developed BN correctly classified 67.74% of instances. The misclassification error was 0.9407. The second BN for predicting the specificity of detection correctly classified 95.895% of instances in 10 classes and the misclassification error was 0.2975. Conclusions The contamination level and duration of outbreaks, alerting threshold, memory, guardband, and whether the weekly pattern was considered or not influence the sensitivity and specificity of outbreak detection and given the C-algorithm parameter settings, we can predict outbreak detection performance quantitatively. In future work, we plan to investigate other predictors of performance and study how these predictions can be used in algorithm and policy choices.
Jafarpour, Nastaran; Precup, Doina; Buckeridge, David
The dengue-2 vaccine virus (S-1) and its parent virus (PR-159) were compared for their ability to infect orally, to replicate in, and subsequently to be transmitted by Aedes aegypti mosquitoes. The vaccine virus was markedly less efficient in its ability ...
B. J. Beaty T. H. G. Aitken
Work has been in four areas: subcloning of NS1, characterization of anti-D3 human sera, subcloning of E, and expression of dengue proteins/peptides. Four HaeIII fragments subclones in lambda gtll have been identified in the correct orientation: Hae272, Ha...
J. M. Ivy
Venezuelan equine encephalitis (VEE) is an emerging infectious disease in Latin America. Outbreaks have been recorded for decades in countries with enzootic circulation, and the recent implementation of surveillance systems has allowed the detection of additional human cases in countries and areas with previously unknown VEE activity. Clinically, VEE is indistinguishable from dengue and other arboviral diseases and confirmatory diagnosis requires the use of specialized laboratory tests that are difficult to afford in resource-limited regions. Thus, the disease burden of endemic VEE in developing countries remains largely unknown, but recent surveillance suggests that it may represent up to 10% of the dengue burden in neotropical cities, or tens-of-thousands of cases per year throughout Latin America. The potential emergence of epizootic viruses from enzootic progenitors further highlights the need to strengthen surveillance activities, identify mosquito vectors and reservoirs and develop effective strategies to control the disease. In this article, we provide an overview of the current status of endemic VEE that results from spillover of the enzootic cycles, and we discuss public health measures for disease control as well as future avenues for VEE research.
Aguilar, Patricia V; Estrada-Franco, Jose G; Navarro-Lopez, Roberto; Ferro, Cristina; Haddow, Andrew D; Weaver, Scott C
Dengue virus (DV) is the most widespread arbovirus, being endemic in over 100 countries, and is estimated to cause 50 million infections annually. Viral factors, such as the genetic composition of the virus strain can play a role in determining the virus virulence and subsequent clinical disease severity. Virus vector competence plays an integral role in virus transmission and is a critical factor in determining the severity and impact of DV outbreaks. Host genetic variations in immune-related genes, including the human leukocyte antigen, have also been shown to correlate with clinical disease and thus may play a role in regulating disease severity. The host's immune system, however, appears to be the primary factor in DV pathogenesis with the delicate interplay of innate and acquired immunity playing a crucial role. Although current research of DV pathogenesis has been limited by the lack of an appropriate animal model, the development of DV therapeutics has been a primary focus of research groups around the world. In the past decade advances in both the development of vaccines and anti-virals have increased in dramatically. This review summarises the current understanding of viral, vector and host factors which contribute to dengue virus pathogenesis and how this knowledge is critically important in the development of pharmaceutical interventions. PMID:23103333
Herrero, Lara J; Zakhary, Andrew; Gahan, Michelle E; Nelson, Michelle A; Herring, Belinda L; Hapel, Andrew J; Keller, Paul A; Obeysekera, Maheshi; Chen, Weiqiang; Sheng, Kuo-Ching; Taylor, Adam; Wolf, Stefan; Bettadapura, Jayaram; Broor, Shobha; Dar, Lalit; Mahalingam, Suresh
OBJECTIVE: The organization of water supply to and on ships differs considerably from that of water supply on land. Risks of contamination can arise from source water at the port or during loading, storage, or distribution on the ship. The purpose of this article is to review documented outbreaks of waterborne diseases associated with passenger, cargo, fishing, and naval ships to identify contributing factors so that similar outbreaks can be prevented in the future. METHODS: The authors reviewed 21 reported outbreaks of waterborne diseases associated with ships. For each outbreak, data on pathogens/toxins, type of ship, factors contributing to outbreaks, mortality and morbidity, and remedial action are presented. RESULTS: The findings of this review show that the majority of reported outbreaks were associated with passenger ships and that more than 6,400 people were affected. Waterborne outbreaks due to Enterotoxigenic Escherichia coli, noroviruses, Salmonella spp, Shigella sp, Cryptosporidium sp, and Giardia lamblia occurred on ships. Enterotoxigenic E. coli was the pathogen most frequently associated with outbreaks. One outbreak of chemical water poisoning also occurred on a ship. Risk factors included contaminated port water, inadequate treatment, improper loading techniques, poor design and maintenance of storage tanks, ingress of contamination during repair and maintenance, cross-connections, back siphonage, and insufficient residual disinfectant. CONCLUSIONS: Waterborne disease outbreaks on ships can be prevented. The factors contributing to outbreaks emphasize the need for hygienic handling of water along the supply chain from source to consumption. A comprehensive approach to water safety on ships is essential. This may be achieved by the adoption of Water Safety Plans that cover design, construction, operation, and routine inspection and maintenance.
Rooney, Roisin M.; Bartram, Jamie K.; Cramer, Elaine H.; Mantha, Stacey; Nichols, Gordon; Suraj, Rohini; Todd, Ewen C. D.
Bark beetle outbreaks can kill a large number of trees—in fact, insect outbreaks affect an area similar in size to that affected by forest fires annually across North America. Trees absorb carbon dioxide, so bark beetle outbreaks can significantly affect regional carbon dynamics. In general, immediately after an outbreak, carbon uptake by trees decreases. Dead trees become snags, which may fall to the ground several or more years after the outbreak. After snags fall, decomposition increases. Carbon uptake begins to recover years to decades after a bark beetle outbreak. There have been few studies of biogeochemical cycling following outbreaks, and those studies have shown a variety of effects in different forests.
Between December 2009 and the end of January 2010, the largest hitherto known outbreak of Legionella in Germany took place in the cities of Ulm and Neu-Ulm. Of a total of 64 patients involved, 60 patients had to be hospitalized, and 5 patients died from the infection. This event was caused by a wet cooling tower of a large air conditioning system in the city center of Ulm. The search for the source of the Legionella emission was extremely difficult, since these plants are neither notifiable nor subject to authorization in Germany. We report about the search for the source and the measures to control the outbreak. We also discuss communication and coordination during these investigations. Regulatory measures as proposed by the World Health Organization (WHO) and the European Network for Legionellosis (EWGLI) and already implemented in numerous other European countries would be desirable to prevent such outbreaks in the future. PMID:22015788
Freudenmann, M; Kurz, S; von Baum, H; Reick, D; Schreff, A M; Essig, A; Lück, C; Gonser, T; Brockmann, S O; Härter, G; Eberhardt, B; Embacher, A; Höller, C
This study was designed to conduct systematic reviews of existing evaporative cooling system maintenance guidelines and of published Legionnaires' disease outbreaks to determine what, if any, maintenance practices were in place at the time of the disease outbreaks and then to contrast the reported practices with the published guidelines for evaporative cooling systems. For the first review, similarities in the reported recommendations were assessed; in the second review, any reported information about the state of the evaporative cooling system during the outbreak investigation was summarized. The systematic reviews yielded 38 current guidelines for evaporative cooling systems and 38 published outbreak investigations. The guidelines varied regarding the recommended type and dose of biocides, frequency of general inspections and total system maintenance, the preferred disinfection and cleaning procedures when testing a system for microbiological contamination, the type and frequency of testing procedures, and interpretation of test results. Overall, the maintenance guidelines did not contain sufficiently detailed procedures to prevent the problems that were observed in the outbreak investigations. These maintenance procedures included lack or improper use of a biocide; infrequent testing for microbiological contamination; improper use or maintenance of drift eliminators; and lack of a total system cleaning within 6 months of the outbreak for cooling systems that were either under continuous use, recently started up, or frequently switched on and off. This study suggests that more specific and standardized maintenance guidelines for the control of Legionella bacteria are needed and that these guidelines must be properly implemented to help reduce further Legionnaires' disease outbreaks associated with evaporative cooling systems. PMID:21416443
Rangel, Kelly M; Delclos, George; Emery, Robert; Symanski, Elaine
It was recently reported that disease severity increased during the 1997 Cuban dengue 2 virus epidemic and it was suggested that this might be explained by the appearance of neutralization resistant escape mutants. We investigated these observations and ideas by sequencing 20 dengue 2 virus isolates obtained during the early (low case fatality rate) and the late (high case fatality rate) phases of the outbreak. Our results showed total conservation of the E gene sequence for these isolates suggesting that the selection of envelope gene escape mutants was not the determinant of increased disease severity. Alignment of these sequences with those available in GenBank, followed by Maximum likelihood phylogenetic analysis generated a tree, which indicated that our isolates are closely related to the virus that circulated in Venezuela in 1997/98 and subsequently in Martinique in 1998. This "American/Asian" genotype has therefore gradually dispersed across the Caribbean region during the past 5 years. PMID:15578237
Rodriguez-Roche, R; Alvarez, M; Gritsun, T; Rosario, D; Halstead, S; Kouri, G; Gould, E A; Guzman, M G
Dengue virus (DENV) causes the most significant mosquito-borne viral disease in the world in terms of illness, death, and economic cost, due to the lack of an approved vaccine or antiviral. Infections with one of the four serotypes of DENV (DENV1–4) can result in diseases ranging from an acute, self-limiting febrile illness (dengue fever, DF) to life-threatening dengue hemorrhagic fever
Lauren E. Yauch; Sujan Shresta
Saliva was collected prospectively from patients presenting with suspected dengue infection 4 to 8 days after the onset of symptoms and assayed by a commercial dengue immunoglobulin M (IgM) and IgG capture enzyme-linked immunosorbent assay (ELISA) (PanBio Dengue Duo ELISA). Laboratory diagnosis was based on virus isolation and on hemagglutination inhibition (HAI) assay and an in-house IgM and IgG capture
ANDREA J. CUZZUBBO; DAVID W. VAUGHN; ANANDA NISALAK; SAROJ SUNTAYAKORN; JOHN AASKOV; PETER L. DEVINE
Background: The economic effects of waterborne outbreaks have rarely been reported. A large waterborne outbreak occurred in the town of Nokia in Finland in 2007 with half of the population in the contaminated area suffering from gastroenteritis. We studied the healthcare costs of this outbreak. Methods: Healthcare costs were studied using register data from the Nokia Health Care Centre, data collected in the regional university hospital, and data from laboratory register on stool samples. Results: Total excess healthcare costs were EUR 354,496, which is approximately EUR 10 per resident of Nokia. There were 2052 excess visits because of gastroenteritis in Nokia Health Care Centre, 403 excess episodes in the university hospital, and altogether over 2000 excess stool samples due to the outbreak. Care in the Nokia Health Care Centre accounted for 44% and care in the university hospital for 42% of the excess healthcare costs while stool samples accounted for only 10%. Conclusions: Despite the high morbidity, the total cost was low because most patients had a relatively mild illness. The situation would have been worse if the microbes involved had been more hazardous or if the financial situation of the community had been worse. Prevention of waterborne outbreaks is important, as there is a risk of severe short- and long-term health effects and substantial health-economic costs. PMID:23703625
Huovinen, Elisa; Laine, Janne; Virtanen, Mikko J; Snellman, Marja; Hujanen, Timo; Kiiskinen, Urpo; Kujansuu, Eila; Lumio, Jukka; Ruutu, Petri; Kuusi, Markku
In Martinique, Aedes aegypti, the vector of dengue viruses has been the target of insecticide control for more than 35 years. Despite significant control efforts, dengue has become a major disease of public health concern. We conducted a population genetic analysis based on isoenzyme variations combined with an estimation of infection rate to a dengue virus among 26 Ae. aegypti samples. Aedes aegypti samples could be differentiated for their susceptibility to dengue infection (infection rates ranging from 42.8% to 98.6%) and showed important genetic variation (significant F(ST) values). PMID:15117302
Yébakima, André; Charles, Céline; Mousson, Laurence; Vazeille, Marie; Yp-Tcha, Marie-Michelle; Failloux, A-B
Epidemic keratoconjunctivitis (EKC) is a highly contagious, severe form of conjunctivitis. During 2008-2010, six unrelated EKC outbreaks associated with human adenovirus (HAdV) in four states were reported to CDC. In total, 411 EKC cases were identified in Florida, Illinois, Minnesota, and New Jersey. In each outbreak, health-care-associated transmission appeared to occur via ophthalmologic examination; however, community transmission was also documented. These outbreaks resulted in significant morbidity and cost resulting from the number of persons affected, duration of the outbreaks, and the temporary closure of a neonatal intensive-care unit (NICU) and several clinics. Clusters of EKC infections should be reported to the appropriate state or local health department. In settings where ophthalmologic care is provided, routine adherence to basic infection control measures and early implementation of enhanced outbreak control measures are essential to prevent HAdV transmission. PMID:23945769
Escherichia coli O157:H7 causes 73,000 illnesses in the United States annually. We reviewed E. coli O157 outbreaks reported to Centers for Disease Control and Prevention (CDC) to better understand the epidemiology of E. coli O157. E. coli O157 outbreaks (?2 cases of E. coli O157 infection with a common epidemiologic exposure) reported to CDC from 1982 to 2002 were reviewed. In that period, 49 states reported 350 outbreaks, representing 8,598 cases, 1,493 (17%) hospitalizations, 354 (4%) hemolytic uremic syndrome cases, and 40 (0.5%) deaths. Transmission route for 183 (52%) was foodborne, 74 (21%) unknown, 50 (14%) person-to-person, 31 (9%) waterborne, 11 (3%) animal contact, and 1 (0.3%) laboratory-related. The food vehicle for 75 (41%) foodborne outbreaks was ground beef, and for 38 (21%) outbreaks, produce.
Sparling, Phyllis H.; Crowe, Collen; Griffin, Patricia M.; Swerdlow, David L.
In 2010, 7/44 (16%) reported foodborne outbreaks in Finland were linked with raw beetroot consumption. We reviewed data from the national outbreak registry in order to hypothesize the aetiology of illness and to prevent further outbreaks. In the seven outbreaks, 124 cases among 623 respondents were identified. Consumption of raw beetroot was strongly associated with gastrointestinal illness (relative risk 8?99, 95% confidence interval 6?06-13?35). The illness was characterized by sudden onset of gastrointestinal symptoms; the median incubation time was 40 min and duration of illness 5 h. No common foodborne pathogens or toxins were found in either clinical or beetroot samples, but all tested beetroot samples were of poor quality according to total bacterial counts. Beta-haemolytic Pseudomonas fluorescens was detected in several beetroot samples but its effect on human health is unknown. No outbreaks were reported after the Finnish Food Safety Authority Evira advised against serving raw beetroot in institutional canteens. PMID:23068603
Jacks, A; Toikkanen, S; Pihlajasaari, A; Johansson, T; Hakkinen, M; Hemminki, K; Hokkanen, P; Käpyaho, A; Kärnä, A; Valkola, K; Niskanen, T; Takkinen, J; Kuusi, M; Rimhanen-Finne, R
The resurgence of dengue (DEN) virus infections in the last few decades coupled with the lack of a preventive vaccine and specific antiviral drugs has jointly contributed to making this a significant global public health problem. Currently, symptomatic supportive treatment and fluid replacement therapy are the only means available to minimize DEN-induced mortality. As the clinical symptoms associated with DEN
Menaka D. Hapugoda; Gaurav Batra; W. Abeyewickreme; S. Swaminathan; N. Khanna
Dengue is a significant public health problem worldwide. Despite the important social and clinical impact, there is no vaccine or specific antiviral therapy for prevention and treatment of dengue virus (DENV) infection. Considering the above, drug discovery research for dengue is of utmost importance; in addition natural marine products provide diverse and novel chemical structures with potent biological activities that must be evaluated. In this study we propose a target-free approach for dengue drug discovery based on a novel, rapid, and economic in situ enzyme-linked immunosorbent assay and the screening of a panel of marine seaweed extracts. The in situ ELISA was standardized and validated for Huh7.5 cell line infected with all four serotypes of DENV, among them clinical isolates and a laboratory strain. Statistical analysis showed an average S/B of 7.2 and Z-factor of 0.62, demonstrating assay consistency and reliability. A panel of fifteen seaweed extracts was then screened at the maximum non-toxic dose previously determined by the MTT and Neutral Red cytotoxic assays. Eight seaweed extracts were able to reduce DENV infection of at least one serotype tested. Four extracts (Phaeophyta: Canistrocarpus cervicornis, Padina gymnospora; Rhodophyta: Palisada perforate; Chlorophyta: Caulerpa racemosa) were chosen for further evaluation, and time of addition studies point that they might act at an early stage of the viral infection cycle, such as binding or internalization. PMID:23227238
Koishi, Andrea Cristine; Zanello, Paula Rodrigues; Bianco, Éverson Miguel; Bordignon, Juliano; Nunes Duarte dos Santos, Claudia
Aim: The objective of this study is to present epidemiological characteristics and clinical symptoms of dengue fever cases in Czech workers who acquired the infection while working on the island of Fushivelavaru, Maldives. Furthermore, the study compares the sensitivity of novel direct detection assays, i.e. Real-Time Polymerase Chain Reaction (RT-PCR) and detection of Dengue NS1 antigen.Material and Methods: The retrospective study evaluated the clinical course of dengue fever cases in Czech workers returning from a job in the Maldives who were diagnosed with dengue virus infection from September 1 to October 31, 2012. The laboratory diagnosis of dengue fever was based on the serological detection of IgM and IgG antibodies, detection of dengue NS1 antigen by enzyme-linked immunosobent assay (ELISA), and detection of dengue virus DNA by RT-PCR. Results: The infection with dengue virus was confirmed in 18 males with a median age of 40 years (IQR 36-47) who returned from a job in the Maldives. Only one patient required admission to the hospital while the others were treated on an outpatient basis. The most frequently observed symptoms were fever (18), headache (9), muscle and joint pain (8 and 7, respectively), and rash (9). Typical laboratory findings were leukocytopenia and thrombocytopenia, a low CRP level, and elevated aminotransferase activity. The clinical course was uncomplicated in all patients. The dengue NS1 antigen detection (positive in all 10 patients with acute dengue fever) showed significantly higher sensitivity than the detection of viral RNA using RT-PCR (positive in 4 patients), p = 0.011. Conclusion: Although the vast majority of dengue fever cases are diagnosed among travellers returning from the tropics, the presented study points out the risks posed by dengue fever to long-term workers in endemic areas. The infection in the serologically naïve hosts is usually uncomplicated; however, infected persons are at significant risk of developing a severe complicated clinical course if challenged by another serotype. Furthermore, sick leaves or premature departures cause a considerable economic burden to employers. In the diagnosis of acute dengue fever, preference should be given to highly sensitive and specific tests for the direct detection of dengue virus (NS1 antigen and RT-PCR assays). Keywords: dengue - flaviviruses - imported infections - fever. PMID:24116697
Trojánek, Milan; Tomí?ková, Dora; Rohá?ová, Hana; Kosina, Pavel; Gebouský, Jan; Dvo?ák, Jan; Chmelik, Vaclav; Batistová, Kv?toslava; Husa, Petr; Maixner, Jan; Sojková, Nad?žda; Zelená, Hana; Marešová, Vilma; Stejskal, František
Severe forms of dengue fever, dengue haemorrhagic fever, and dengue shock syndrome, were not prominent in the Americas until the epidemic of Cuba in 1981. Since that time, they have spread to other countries in Central and South America, correlating with the spread of dengue type 2 viruses related to Southeast Asian strains. We report here the complete genomic sequence
H. Tolou; V. Mercier; M. R. Pisano; X. de Lamballerie; P. de Micco; J. P. Durand
Severe dengue virus (DENV) disease symptoms, including dengue hemorrhagic fever and dengue shock syndrome, have been correlated with the presence of pre-existing antibodies that enhance rather than neutralize infections in Fc receptor bearing cells. These antibodies can originate from previous infection with a different serotype of dengue, or from waning antibody titers that occur in infants and young children as
Cindo O. Nicholson; Joshua M. Costin; Dawne K. Rowe; Li Lin; Ekachai Jenwitheesuk; Ram Samudrala; Sharon Isern; Scott F. Michael
Dengue fever is a viral infection transmitted by mosquitoes (Aedes Aegypti). WHO estimates that 40% of the world's population live in areas endemic for dengue fever, and that there are approximately 50 million cases of dengue in- fection worldwide every year. This study aims to measure the economic consequences of dengue hemor- rhagic fever in Southern Vietnam on family level.
Mette Lønstrup Harving; Ho Chi
The clinical and laboratory parameters of dengue in children, along with predictive markers of dengue shock syndrome (DSS), were studied in Mumbai in 2003. In 2004, there was again a resurgence of dengue in Mumbai and a prospective study of children admitted in hospital was undertaken to determine the clinical and laboratory features of dengue, with specific features in order
Ira Shah; Bhushan Katira
Severe forms of dengue virus disease, known as dengue hemorrhagic fever and dengue shock syndrome, result from an aberrant immune response involving antibody-dependent enhance- ment of infection, thrombocytopenia, and a loss of vascular integrity, culminating in hemorrhage, shock, and in some cases, death. Several studies have indicated that dengue virus infection results in the induction of apoptosis of certain cells
Michael G. Brown; Yan Y. Huang; Jean S. Marshall; Christine A. King; David W. Hoskin; Robert Anderson
Introduction: Dengue is a major public health problem in Singapore. Age-specific dengue morbidity rates are highest in the young adult population, unlike in many other Southeast Asian countries where dengue is mainly a paediatric disease. Hence, the World Health Organization (WHO) guidelines on dengue diagnosis and management which were developed using the paediatric experiences, may not be suitable for the
Eng-Eong Ooi; Thomas Tolfvenstam; Yee-Sin Leo; Martin L Hibberd; Lee-Ching Ng; Yee-Ling Lai
Cholera remains a public health concern in developing countries because of its high morbidity and mortality. This study was designed to assess the magnitude of and factors responsible for an outbreak in a South Indian village and to implement measures for containing and preventing the recurrence of such outbreaks. Data was obtained by surveying households in the village to identify cases and assess factors responsible for the outbreak. A sanitary survey of the water supply system was performed to identify the cause of the outbreak. Preventive measures were implemented by setting up a rapid response team to manage cases and provide safe drinking water and health education regarding the prevention of such outbreaks. A total of 73 cases were reported during the outbreak, an attack rate of 17.5%. Attack rates were similar among males and females, and the highest rates were observed among the elderly (33.3%), while the lowest rates were observed among adults (14.7%). There were no deaths reported due to cholera in the village. Most households (81%) surveyed did not use any method of water purification, 79.7% practiced open field defecation and 58.2% practiced inadequate hand washing, indicating poor sanitary practices. Cases were most commonly observed in houses which did not practice any method of water purification (p<0.001) and among people living below the poverty line (p=0.02). Despite the high attack rate, no deaths were reported, largely thanks to timely medical and preventive interventions. PMID:23290091
Deepthi, R; Sandeep, S R; Rajini, M; Rajeshwari, H; Shetty, Achal
Background The explosive epidemics of dengue that have been occurring in various countries have stimulated investigation into new approaches to improve understanding of the problem and to develop new strategies for controlling the disease. The objective of this study was to evaluate the characteristics of diffusion of the first dengue epidemic that occurred in the city of Salvador in 1995. Methods The epidemiological charts and records of notified cases of dengue in Salvador in 1995 constituted the source of data. The cases of the disease were georeferenced according to census areas (spatial units) and epidemiological weeks (temporal unit). Kernel density estimation was used to identify the pattern of spatial diffusion using the R-Project computer software program. Results Of the 2,006 census areas in the city, 1,400 (70%) registered cases of dengue in 1995 and the spatial distribution of these records revealed that by the end of 1995 practically the entire city had been affected by the virus, with the largest concentration of cases occurring in the western region, composed of census areas with a high population density and predominantly horizontal residences compared to the eastern region of the city, where there is a predominance of vertical residential buildings. Conclusion The pattern found in this study shows the characteristics of the classic process of spreading by contagion that is common to most infectious diseases. It was possible to identify the epicenter of the epidemic from which centrifugal waves of the disease emanated. Our results suggest that, if a more agile control instrument existed that would be capable of rapidly reducing the vector population within a few days or of raising the group immunity of the population by means of a vaccine, it would theoretically be possible to adopt control actions around the epicenter of the epidemic and consequently reduce the incidence of the disease in the city. This finding emphasizes the need for further research to improve the technology available for the prevention of this disease.
Barreto, Florisneide R; Teixeira, Maria Gloria; Costa, Maria da Conceicao N; Carvalho, Marilia S; Barreto, Mauricio L
Background Control and prevention of dengue relies heavily on the application of insecticides to control dengue vector mosquitoes. In Colombia, application of the larvicide temephos to the aquatic breeding sites of Aedes aegypti is a key part of the dengue control strategy. Resistance to temephos was recently detected in the dengue-endemic city of Cucuta, leading to questions about its efficacy as a control tool. Here, we characterize the underlying mechanisms and estimate the operational impact of this resistance. Methodology/Principal Findings Larval bioassays of Ae. aegypti larvae from Cucuta determined the temephos LC50 to be 0.066 ppm (95% CI 0.06–0.074), approximately 15× higher than the value obtained from a susceptible laboratory colony. The efficacy of the field dose of temephos at killing this resistant Cucuta population was greatly reduced, with mortality rates <80% two weeks after application and <50% after 4 weeks. Neither biochemical assays nor partial sequencing of the ace-1 gene implicated target site resistance as the primary resistance mechanism. Synergism assays and microarray analysis suggested that metabolic mechanisms were most likely responsible for the temephos resistance. Interestingly, although the greatest synergism was observed with the carboxylesterase inhibitor, DEF, the primary candidate genes from the microarray analysis, and confirmed by quantitative PCR, were cytochrome P450 oxidases, notably CYP6N12, CYP6F3 and CYP6M11. Conclusions/Significance In Colombia, resistance to temephos in Ae. aegypti compromises the duration of its effect as a vector control tool. Several candidate genes potentially responsible for metabolic resistance to temephos were identified. Given the limited number of insecticides that are approved for vector control, future chemical-based control strategies should take into account the mechanisms underlying the resistance to discern which insecticides would likely lead to the greatest control efficacy while minimizing further selection of resistant phenotypes.
Grisales, Nelson; Poupardin, Rodolphe; Gomez, Santiago; Fonseca-Gonzalez, Idalyd; Ranson, Hilary; Lenhart, Audrey
Phylogenetic evidence suggests that endemic and epidemic dengue viruses (DENV), transmitted among humans by the anthropophilic mosquitoes Aedes aegypti and Ae. albopictus, emerged when ancestral, sylvatic DENV transmitted among nonhuman primates by sylvatic Aedes mosquitoes adapted to these peridomestic vectors. We tested this hypothesis by retrospectively examining evidence for adaptation of epidemic and endemic versus sylvatic strains of DENV-2 to Ae. albopictus and Ae. aegypti. First and second-generation offspring of mosquitoes from different geographic regions in the Americas and Southeast Asia were tested for their susceptibility to epidemic/endemic and sylvatic DENV-2 isolates from West Africa, Southeast Asia, and Oceania. Both Aedes species were highly susceptible (up to 100% infected) to endemic/epidemic DENV-2 strains after ingesting artificial blood meals but significantly less susceptible (as low as 0%) to sylvatic DENV-2 strains. Our findings support the hypothesis that adaptation to peridomestic mosquito vectors mediated dengue emergence from sylvatic progenitor viruses.
Moncayo, Abelardo C.; Fernandez, Zoraida; Ortiz, Diana; Diallo, Mawlouth; Sall, Amadou; Hartman, Sammie; Davis, C. Todd; Coffey, Lark; Mathiot, Christian C.; Tesh, Robert B.
Severe acute respiratory syndrome (SARS) was an unknown disease barely 3 years ago. After the World Health Organization declared the world SARS-free on 5 July 2003, there were episodic recurrences of SARS between September 2003 and May 2004, including 4 cases of laboratory-acquired SARS. SARS posed a mammoth challenge because of the impact of nosocomial transmission on healthcare manpower and facilities, and the resources needed for controlling and preventing further spread. Through worldwide scientific collaboration, the medical community has made much progress in unraveling its enigma, though much more needs to be discovered. This paper highlights how we can apply our knowledge of its epidemiology, mode of transmission, clinical course, ICU admission, complications, predictors of poor outcome, treatment and infection control to help us avert a catastrophic outbreak, and to manage our resources and patients. SARS preparedness and response planning must be flexible and dynamic so that appropriate measures can be implemented as an outbreak progresses. Even if SARS does not reemerge, the experience gained from such planning is valuable in preparing for threats of bioterrorism or a global avian influenza A (H5N1) virus pandemic. PMID:16830006
Tai, Dessmon Y H
Eight of 69 (12%) healthy adult volunteers vaccinated with monovalent live-attenuated dengue virus (DENV) vaccine candidates had atypical antibody responses, with depressed IgM:IgG antibody ratios and induction of high-titer hemagglutination-inhibiting and neutralizing (NT) antibodies to all four DENV serotypes. These features suggested flavivirus exposure prior to DENV vaccination, yet no volunteer had a history of previous flavivirus infection, flavivirus vaccination,
N. KANESA-THASAN; W. SUN; G. V. LUDWIG; C. ROSSI; J. R. PUTNAK; J. A. MANGIAFICO; B. L. INNIS; R. EDELMAN
\\u000a Dengue virus is sensed in mammalian cells by Toll-like receptors and DExD\\/H box RNA helicases, triggering a Type 1 interferon\\u000a response. Interferon acts upon infected and noninfected cells by stimulating the JAK\\/STAT signaling pathway resulting in the\\u000a activation of interferon stimulated genes that lead cells toward the establishment of an antiviral response. The recognition\\u000a of the importance of this rapid
Jorge L. Muñoz-Jordán
The development of animal models of dengue virus (DENV) infection and disease has been challenging, as epidemic DENV does not naturally infect non-human species. Non-human primates (NHPs) can sustain viral replication in relevant cell types and develop a robust immune response, but they do not develop overt disease. In contrast, certain immunodeficient mouse models infected with mouse-adapted DENV strains show signs of severe disease similar to the 'vascular-leak' syndrome seen in severe dengue in humans. Humanized mouse models can sustain DENV replication and show some signs of disease, but further development is needed to validate the immune response. Classically, immunocompetent mice infected with DENV do not manifest disease or else develop paralysis when inoculated intracranially; however, a new model using high doses of DENV has recently been shown to develop hemorrhagic signs after infection. Overall, each model has its advantages and disadvantages and is differentially suited for studies of dengue pathogenesis and immunopathogenesis and/or pre-clinical testing of antiviral drugs and vaccines. PMID:22355452
Zompi, Simona; Harris, Eva
Dengue fever is the most prevalent mosquito-borne viral disease globally with about 100 million cases of acute dengue annually. Severe dengue infection can result in a life-threatening illness. In the absence of either a licensed vaccine or antiviral drug against dengue, therapeutic antibodies that neutralize dengue virus (DENV) may serve as an effective medical countermeasure against severe dengue. However, therapeutic antibodies would need to effectively neutralize all four DENV serotypes. It must not induce antibody-dependent enhancement of DENV infection in monocytes/macrophages through Fc gamma receptor (Fc?R)-mediated phagocytosis, which is hypothesized to increase the risk of severe dengue. Here, we review the strategies and technologies that can be adopted to develop antibodies for therapeutic applications. We also discuss the mechanism of antibody neutralization in the cells targeted by DENV that express Fc gamma receptor. These studies have provided significant insight toward the use of therapeutic antibodies as a potentially promising bulwark against dengue. PMID:24093625
Chan, Kuan Rong; Ong, Eugenia Z; Ooi, Eng Eong
Perinatal transmission of dengue virus was confirmed by the evidence of virus in fetal tissue, newborn serum, and placenta of pregnant women. Abortion, several different clinical findings, and placental inflammatory findings were documented. No association was seen between severity of maternal dengue and disease of the newborn. PMID:23916226
Ribeiro, Christiane Fernandes; Lopes, Vânia Glória Silami; Brasil, Patrícia; Coelho, Janice; Muniz, Adriana Gouveia; Nogueira, Rita Maria Ribeiro
Dengue is a febrile illness caused by any of the four dengue virus types (DENV-1 to -4, genus Flavivirus, family Flaviviridae) mainly transmitted by the mosquito Aedes aegypti. DENV can be transmitted by blood transfusion. Dengue has been historically present in the continental United States (US), in the state of Hawaii, and in the US insular territories in the Caribbean and the Pacific. During the second half of the 20th century, most of the cases reported in the US were imported cases brought to the country by travelers. Since 2009, cases of autochthonous dengue have been recognized in the state of Florida after 75 years of absence, followed by intensification of transmission in endemic places including the US territories of US Virgin Islands and Puerto Rico, which experienced a large dengue epidemic in 2010. The widespread distribution of dengue mosquito vectors, deficient mosquito control measures and increased frequency of DENV-infected visitors to the US coming from dengue-endemic locations or places experiencing epidemics appear to be jointly responsible for the emergence and reemergence of dengue in the US and its territories.
Dengue fever is a reportable disease in Germany. Surveillance data from 2001 and 2002 were analyzed and compared to travel patterns. Imported dengue fever increased strongly in this time. Most infections were acquired in Southeast Asia, specifically Thailand. The 2002 epidemic in Brazil was also reflected in these data.
Schoneberg, Irene; Krause, Gerard; Claus, Hermann; Ammon, Andrea; Stark, Klaus
The variability of the insect-borne disease dengue in Puerto Rico was studied in relation to climatic variables in the period 1979-2005. Annual and monthly reported dengue cases were compared with precipitation and temperature data. Results show that the incidence of dengue in Puerto Rico was relatively constant over time despite global warming, possibly due to the offsetting effects of declining rainfall, improving health care and little change in population. Seasonal fluctuations of dengue were driven by rainfall increases from May to November. Year-to-year variability in dengue cases was positively related to temperature, but only weakly associated with local rainfall and an index of El Nino Southern Oscillation (ENSO). Climatic conditions were mapped with respect to dengue cases and patterns in high and low years were compared. During epidemics, a low pressure system east of Florida draws warm humid air over the northwestern Caribbean. Long-term trends in past observed and future projected rainfall and temperatures were studied. Rainfall has declined slowly, but temperatures in the Caribbean are rising with the influence of global warming. Thus, dengue may increase in the future, and it will be necessary to anticipate dengue epidemics using climate forecasts, to reduce adverse health impacts. PMID:18821372
Jury, Mark R
The aim of this study was to examine retrospective dengue-illness classification using only clinical laboratory data, without relying on X-ray, ultrasound, or percent hemoconcentration. We analyzed data from a study of children who presented with acute febrile illness to two hospitals in Thailand. Multivariable logistic regression models were used to distinguish: (1) dengue hemorrhagic fever (DHF) versus dengue fever (DF), (2) DHF versus DF + other febrile illness (OFI), (3) dengue versus OFI, and (4) severe dengue versus non-severe dengue + OFI. Data from the second hospital served as a validation set. There were 1,227 patients in the analysis. The sensitivity of the models ranged from 89.2% (dengue versus OFI) to 79.6% (DHF versus DF). The models showed high sensitivity in the validation dataset. These models could be used to calculate a probability and classify patients based on readily available clinical laboratory data, and they will need to be validated in other dengue-endemic regions. PMID:20889865
Potts, James A; Thomas, Stephen J; Srikiatkhachorn, Anon; Supradish, Pra-on; Li, Wenjun; Nisalak, Ananda; Nimmannitya, Suchitra; Endy, Timothy P; Libraty, Daniel H; Gibbons, Robert V; Green, Sharone; Rothman, Alan L; Kalayanarooj, Siripen
The aim of this study was to examine retrospective dengue-illness classification using only clinical laboratory data, without relying on X-ray, ultrasound, or percent hemoconcentration. We analyzed data from a study of children who presented with acute febrile illness to two hospitals in Thailand. Multivariable logistic regression models were used to distinguish: (1) dengue hemorrhagic fever (DHF) versus dengue fever (DF), (2) DHF versus DF + other febrile illness (OFI), (3) dengue versus OFI, and (4) severe dengue versus non-severe dengue + OFI. Data from the second hospital served as a validation set. There were 1,227 patients in the analysis. The sensitivity of the models ranged from 89.2% (dengue versus OFI) to 79.6% (DHF versus DF). The models showed high sensitivity in the validation dataset. These models could be used to calculate a probability and classify patients based on readily available clinical laboratory data, and they will need to be validated in other dengue-endemic regions.
Potts, James A.; Thomas, Stephen J.; Srikiatkhachorn, Anon; Supradish, Pra-on; Li, Wenjun; Nisalak, Ananda; Nimmannitya, Suchitra; Endy, Timothy P.; Libraty, Daniel H.; Gibbons, Robert V.; Green, Sharone; Rothman, Alan L.; Kalayanarooj, Siripen
Dengue is a febrile illness caused by any of the four dengue virus types (DENV-1 to -4, genus Flavivirus, family Flaviviridae) mainly transmitted by the mosquito Aedes aegypti. DENV can be transmitted by blood transfusion. Dengue has been historically present in the continental United States (US), in the state of Hawaii, and in the US insular territories in the Caribbean and the Pacific. During the second half of the 20th century, most of the cases reported in the US were imported cases brought to the country by travelers. Since 2009, cases of autochthonous dengue have been recognized in the state of Florida after 75 years of absence, followed by intensification of transmission in endemic places including the US territories of US Virgin Islands and Puerto Rico, which experienced a large dengue epidemic in 2010. The widespread distribution of dengue mosquito vectors, deficient mosquito control measures and increased frequency of DENV-infected visitors to the US coming from dengue-endemic locations or places experiencing epidemics appear to be jointly responsible for the emergence and reemergence of dengue in the US and its territories. PMID:23865061
Añez, Germán; Rios, Maria
Objective. Severe dengue affects all age groups in the Americas, but little detailed infor- mation is available about this disease in the elderly. The objective of this article is to describe the disease in this age group. Methods. We reviewed suspected dengue-case investigation forms submitted with diagnos- tic samples as well as clinical reports from infection control nurses in Puerto
Enid J. García-Rivera; José G. Rigau-Pérez
Vertical transmission of dengue type 1 virus was demonstrated by a strain of Haemagogus equinus mosquitoes from Panama. Parental females were infected by intrathoracic inoculation and egg production was stimulated by feeding on mice. Dengue 1 virus was detected in fourth instar larval progeny obtained from two installment hatches of eggs. Minimum filial infection rates ranged up to 1:495. PMID:1675252
de Souza, M; Freier, J E
Using active microbiologic surveillance and enhanced infection control measures to control an outbreak of health care-associated extended-spectrum beta-lactamase-producing Klebsiella pneumoniae infections--New Jersey, 2007.
Between April and June 2007, an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae infections occurred in an intensive care unit in New Jersey. The outbreak was contained through active microbiologic surveillance, contact precautions, cohorting, and frequent room cleaning. This outbreak demonstrates the importance of rapid response in identifying and isolating patients to prevent further transmission. PMID:18834744
Langer, Adam J; Lafaro, Pat; Genese, Carol A; McDonough, Pauline; Nahass, Ron; Robertson, Corwin
Background: The pathogenesis of the severe form of dengue virus infection, dengue hemorrhagic fever, is still obscure. A major research objective has been to determine which body organs are being damaged by dengue virus in this form of dengue. Research has been difficult because dengue hemorrhagic fever is sporadic and tends to occur in parts of the world where modern
Daoroong Kangwanpong; Natth Bhamarapravati; Helen L. Lucia
We investigated a norovirus outbreak (genotype GII.2) affecting 9 members of a soccer team. Illness was associated with touching a reusable grocery bag or consuming its packaged food contents (risk difference, 0.636; P < .01). By polymerase chain reaction, GII norovirus was recovered from the bag, which had been stored in a bathroom used before the outbreak by a person with norovirus-like illness. Airborne contamination of fomites can lead to subsequent point-source outbreaks. When feasible, we recommend dedicated bathrooms for sick persons and informing cleaning staff (professional or otherwise) about the need for adequate environmental sanitation of surfaces and fomites to prevent spread.
Repp, Kimberly K.; Keene, William E.
Summary Antisera from dengue patients and dengue virus infected rabbits recognized octapeptides corresponding to linear amino acid sequences in the envelope protein of dengue 2 (Jamaica 1409). Although no peptide was recognized by sera from all dengue infected hosts, two peptides (216LPLPWLPG223 and448FSGVSWTM455) were recognized by sera from all dengue 2 infected rabbits. One of these448FSGVSWTM455 was also recognized by
J. G. Aaskov; H. M. Geysen; T. J. Mason
Background Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level. Methods/Principal Findings We carried out intrathoracic Dengue 2 virus (DENV-2) infections in Aedes aegypti females and recorded their locomotor activity behavior. We observed an increase of up to ?50% in the activity of infected mosquitoes compared to the uninfected controls. Conclusions Dengue infection alters mosquito locomotor activity behavior. We speculate that the higher levels of activity observed in infected Aedes aegypti females might involve the circadian clock. Further studies are needed to assess whether this behavioral change could have implications for the dynamics of Dengue virus transmission.
Luz, Paula M.; Castro, Marcia G.; Lourenco-de-Oliveira, Ricardo; Sorgine, Marcos H. F.; Peixoto, Alexandre A.
We report epidemiology of dengue infection as revealed through a hospital based surveillance for dengue infection over a 3 year period in Lucknow, U.P., India. In 2003-2005, children with acute febrile encephalopathy (AFE) and in 2005-2006, children with acute undifferentiated febrile illness (AUFI) were enrolled. IgM antibodies to dengue were tested by ELISA in acute serum. A total of 118/563 (20.9%) patients tested positive for dengue antibodies. Dengue transmission occurred round the year in the Lucknow region with peak in postmonsoon season and occurred equally in rural and urban areas. All the surrounding districts were affected, with no distinct high prevalence areas. PMID:18451453
Tripathi, Piyush; Kumar, Rashmi; Tripathi, Sanjeev; Tambe, J J; Venkatesh, Vimala
Timely and extensive space spraying has been widely used to prevent the spread of dengue fever/dengue hemorrhagic fever (DF/DHF). Field evaluations on its effectiveness have been rarely reported. This study aimed to evaluate the timeliness, coverage, and effectiveness of space spraying for DF/DHF control using a geographic information system (GIS). Longitudinal monitoring of DF/DHF cases and spray activities in Songkhla municipality was done between May 2006 and April 2007. After a case was detected, subsequent cases occurring within a 100 meter radius of the index case's house and between 16-35 days of onset were considered as potential secondary cases. During the study period, 140 cases of DF/DHF were detected. Of these, 25 were identified as secondar