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- A database of circadian and diel rhythmic gene expression in the yellow fever mosquito Aedes aegypti.
Leming MT, Rund SS, Behura SK, et al. A database of circadian and diel rhythmic gene expression in the yellow fever mosquito Aedes aegypti. [JOURNAL ARTICLE]BMC Genomics 2014 Dec 17; 15(1):1128.AbstractPublisher Full TextThe mosquito species Aedes aegypti is the primary vector of many arboviral diseases, including dengue and yellow fevers, that are responsible for a large worldwide health burden. The biological rhythms of mosquitoes regulate many of the physiological processes and behaviors that influence the transmission of these diseases. For insight into the molecular basis of biological rhythms, diel and circadian gene expression profiling has been carried out for many species. To bring these resources to Aedes aegypti researchers, we used microarray technology to carry out a genome wide assessment of gene expression during the 24 hour light/dark (LD) cycle and during constant darkness (DD). The purpose of this report is to describe the methods, the validation of the results, and the organization of this database resource.Description: The Aedes aegypti Circadian Database is a publicly accessible database that can be searched via a text-based query to visualize 44 hour temporal expression patterns of a given gene in Ae. aegypti heads under diel (observed under a 12 hour/12 hour LD cycle) and circadian (observed under DD) conditions. Profiles of gene expression under these conditions were assayed by Nimblegen 12-plex microarrays and rhythmicity was objectively assessed by the JTK_CYCLE algorithm. The output of the search is a graphical representation of the expression data along with computed period length, the time-of-day of gene expression peaks, and statistical determination for rhythmicity.Our results show that at least 7.9% of the gene set present in the Aedes aegypti head are rhythmic under LD conditions and 6.7% can be considered circadian, oscillating under constant dark conditions. We present these results in the Aedes aegypti Circadian Database through Bioclock, a public website hosted by the University of Notre Dame at http://www.nd.edu/~bioclock/. This website allows searchable browsing of this quantitative gene expression information. The visualization allows for gene-by-gene comparison of transcript expression under both diel and circadian conditions, and the results are presented graphically in a plot profile of gene expression. The Ae. aegypti Circadian Database provides a community resource for observing diel and circadian fluctuations in gene expression across the Ae. aegypti genome.
- Seroprevalence screening for the West Nile virus in Malaysia¿s Orang Asli population.
Marlina S, Radzi S, Lani R, et al. Seroprevalence screening for the West Nile virus in Malaysia¿s Orang Asli population. [JOURNAL ARTICLE]Parasit Vectors 2014 Dec 17; 7(1):597.AbstractPublisher Full TextBackgroundWest Nile virus (WNV) infection is an emerging zoonotic disease caused by an RNA virus of the genus Flavivirus. WNV is preserved in the environment through cyclic transmission, with mosquitos, particularly Culexspecies, serving as a vector, birds as an amplifying host and humans and other mammals as dead-end hosts. To date, no studies have been carried out to determine the prevalence of the WNV antibody in Malaysia. The aim of this study was to screen for the seroprevalence of the WNV in Malaysia¿s Orang Asli population.MethodsSerum samples of 742 Orang Asli were collected in seven states in peninsular Malaysia. The samples were assessed to determine the seroprevalence of WNV immunoglobulin (Ig)G with the WNV IgG enzyme-linked immunosorbent assay (ELISA) method. For each individual, we documented the demographic factors. Anti-dengue and anti-tick-borne encephalitis virus IgG ELISA were also performed to rule out a cross reaction. All statistical analyses were performed using the GraphPad Prism 6 (GraphPad Software, Inc.); p values of less than 0.05 were considered significant.ResultsThe serosurvey included 298 men (40.16%) and 444 women (59.84%) of Malaysia¿s Orang Asli. Anti-WNV IgG was found in 9 of the 742 samples (1.21%). The seroprevalence was 0.67% (2 of 298) in men and 1.58% (7 of 444) in women. The presence of anti-WNV IgG was found not to be associated with gender but, however, did correlate with age. The peak seroprevalence was found to be 2.06% (2 of 97) in individuals between 30 to 42 years of age.ConclusionsNo previous studies have examined the seroprevalence of the WNV antibody in the human population in Malaysia, and no clinical reports of infections have been made. Screening for the WNV seroprevalence is very significant because of many risk factors contribute to the presence of WNV in Malaysia, such as the abundance of Culexmosquitoes as the main vector and a high degree of biodiversity, including migratory birds that serve as a reservoir to the virus.
- Estimates of meteorological variability in association with dengue cases in a coastal city in northern Vietnam: an ecological study.
Xuan le TT, Van Hau P, Thu do T, et al. Estimates of meteorological variability in association with dengue cases in a coastal city in northern Vietnam: an ecological study. [Journal Article]Glob Health Action 2014.:23119.AbstractPMC Free Full TextPublisher Full TextDengue fever (DF) is a vector-borne disease that is sensitive to weather and climate variability. To date, however, this relationship in coastal northern Vietnam has not been well documented.This paper aims to examine the associations between meteorological variables and dengue incidence in Haiphong, Vietnam, over the period 2008-2012.Monthly data on dengue incidence from all commune health stations and hospitals of Haiphong (with a total population of ~1.8 million) were obtained in accordance with the WHO's recommendations over a 5-year period (2008-2012). Temperature, rainfall, and humidity were recorded as monthly averages by local meteorological stations. The association between ecologic weather variables and dengue cases was assessed using a Poisson regression model. The estimation of regression parameters was based on the method of maximum likelihood using the R program package.From 2008 through 2012, 507 cases of dengue were reported. The risk of dengue was increased by sevenfold during the September-December period compared with other months over the period 2008-2012. DF cases in Haiphong were correlated with rainfall and humidity. In the multivariable Poisson regression model, an increased risk of dengue was independently associated with months with a higher amount of rainfall (RR=1.06; 95% CI 1.00-1.13 per 50 mm increase) and higher humidity (RR=1.05; 95% CI 1.02-1.08 per 1% increase).These data suggest that rainfall and relative humidity could be used as ecological indicators of dengue risk in Haiphong. Intensified surveillance and disease control during periods with high rainfall and humidity are recommended. This study may provide baseline information for identifying potential long-term effects and adaptation needs of global climate change on dengue in the coming decades.
- Epidemiology of dengue fever in Hanoi from 2002 to 2010 and its meteorological determinants.
Minh An DT, Rocklöv J Epidemiology of dengue fever in Hanoi from 2002 to 2010 and its meteorological determinants. [Journal Article]Glob Health Action 2014.:23074.AbstractPMC Free Full TextPublisher Full TextDengue fever (DF) is a growing public health problem in Vietnam. The disease burden in Vietnam has been increasing for decades. In Hanoi, in contrast to many other regions, extrinsic drivers such as weather have not been proved to be predictive of disease frequency, which limits the usefulness of such factors in an early warning system.The purpose of this research was to review the epidemiology of DF transmission and investigate the role of weather factors contributing to occurrence of DF cases.Monthly data from Hanoi (2002-2010) were used to test the proposed model. Descriptive time-series analysis was conducted. Stepwise multivariate linear regression analysis assuming a negative binomial distribution was established through several models. The predictors used were lags of 1-3 months previous observations of mean rainfall, mean temperature, DF cases, and their interactions.Descriptive analysis showed that DF occurred annually and seasonally with an increasing time trend in Hanoi. The annual low occurred from December to March followed by a gradual increase from April to July with a peak in September, October. The amplitude of the annual peak varied between years. Statistically significant relationships were estimated at lag 1-3 with rainfall, autocorrelation, and their interaction while temperature was estimated as influential at lag 3 only. For these relationships, the final model determined a correlation of 92% between predicted number of dengue cases and the observed dengue disease frequencies.Although the model performance was good, the findings suggest that other forces related to urbanization, density of population, globalization with increasing transport of people and goods, herd immunity, government vector control capacity, and changes in serotypes are also likely influencing the transmission of DF. Additional research taking into account all of these factors besides climatic factors is needed to help developing and developed countries find the right intervention for controlling DF epidemics, and to set up early warning systems with high sensitivity and specificity. Immediate action to control DF outbreak in Hanoi should include an information, communication, and education program that focuses on training Hanoi residents to more efficiently eliminate stagnant puddles and water containers after each rainfall to limit the vector population growth.
- Perceptions of climate change and its impact on human health: an integrated quantitative and qualitative approach.
Toan do TT, Kien VD, Bao Giang K, et al. Perceptions of climate change and its impact on human health: an integrated quantitative and qualitative approach. [Journal Article]Glob Health Action 2014.:23025.AbstractPMC Free Full TextPublisher Full TextThe World Health Organization emphasized that climate change is a significant and emerging threat to public health, especially in lower income populations and tropical/subtropical countries. However, people in Asia and Africa were the least likely to perceive global warming as a threat. In Vietnam, little research has been conducted concerning the perceptions of effects of climate change on human health.The aim of this study was to explore the perceptions on climate change and its impact on human health among people in Hanoi.We applied a combined quantitative and qualitative approach to study perceptions on climate change among people in Hanoi. A total of 1,444 people were recruited, including 754 people living in non-slum areas and 690 people living in slum areas of Hanoi. A structured questionnaire was used to collect quantitative data on their perceptions. In a parallel qualitative study, two focus group discussions and 12 in-depth interviews (IDs) were carried out involving 24 people from both slum and non-slum areas.The majority of the respondents in the study had heard about climate change and its impact on human health (79.3 and 70.1% in non-slum and slum areas, respectively). About one third of the respondents reported that members of their family had experienced illness in the recent summer and winter compared to the same seasons 5 years ago. The most common symptoms reported during hot weather were headaches, fatigue, and dizziness; hypertension and other cardiovascular diseases were also reported. During cold weather, people reported experiencing cough, fever, and influenza, as well as pneumonia and emerging infectious diseases such as dengue and Japanese encephalitis.The observed high level of awareness on the links between climate change and human health may help to increase the success of the National Prevention Program on Climate Change. Moreover, understanding the concerns of the people may help policy makers to develop and implement effective and sustainable adaptation measures for Hanoi City as well as for Vietnam as a whole.
- What diseases are disguised as dengue?
Su PA, Tan CK, Hsu CC, et al. What diseases are disguised as dengue? [LETTER]Am J Emerg Med 2014 Dec 2.Publisher Full Text
- Economic Cost and Burden of Dengue in the Philippines.
Edillo FE, Halasa YA, Largo FM, et al. Economic Cost and Burden of Dengue in the Philippines. [JOURNAL ARTICLE]Am J Trop Med Hyg 2014 Dec 15.AbstractPublisher Full TextDengue, the world's most important mosquito-borne viral disease, is endemic in the Philippines. During 2008-2012, the country's Department of Health reported an annual average of 117,065 dengue cases, placing the country fourth in dengue burden in southeast Asia. This study estimates the country's annual number of dengue episodes and their economic cost. Our comparison of cases between active and passive surveillance in Punta Princesa, Cebu City yielded an expansion factor of 7.2, close to the predicted value (7.0) based on the country's health system. We estimated an annual average of 842,867 clinically diagnosed dengue cases, with direct medical costs (in 2012 US dollars) of $345 million ($3.26 per capita). This is 54% higher than an earlier estimate without Philippines-specific costs. Ambulatory settings treated 35% of cases (representing 10% of direct costs), whereas inpatient hospitals served 65% of cases (representing 90% of direct costs). The economic burden of dengue in the Philippines is substantial.
- Isolation and Characterization of Mayaro Virus from a Human in Acre, Brazil.
Terzian AC, Auguste AJ, Vedovello D, et al. Isolation and Characterization of Mayaro Virus from a Human in Acre, Brazil. [JOURNAL ARTICLE]Am J Trop Med Hyg 2014 Dec 15.AbstractPublisher Full TextMayaro virus (MAYV) is widely distributed throughout South America and is the etiologic agent of Mayaro fever, an acute febrile illness often presenting with arthralgic manifestations. The true incidence of MAYV infection is likely grossly underestimated because the symptomatic presentation is very similar to that of dengue fever and other acute febrile tropical diseases. We report the complete genome sequence of a MAYV isolate detected from an Acrelândia patient presenting with fever, chills, and sweating, but with no arthralgia. Results show that this isolate belongs to genotype D and is closely related to Bolivian strains. Our results suggest that the Acre/Mayaro strain is closely related to the progenitor of these Bolivian strains that were isolated between 2002 and 2006.
- Application of post-PCR methods for analysis of mosquito densovirus.
Jotekratok U, Boonnak K, Suttitheptumrong A, et al. Application of post-PCR methods for analysis of mosquito densovirus. [Journal Article, Research Support, Non-U.S. Gov't]Southeast Asian J Trop Med Public Health 2014 Jul; 45(4):801-7.AbstractAggregator Full TextTwo clades of Aedes densovirus, Aedes aegypti densovirus and Aedes albopictus densovirus, were classified according to the origin of isolation. These two densoviruses were isolated from indigenous mosquitoes and mosquito cell lines, respectively. This group of invertebrate viruses belongs to the subfamily Densovirinae of the Parvoviridae family and infects only insects. Several types of densoviruses have been isolated from mosquitoes especially Aedes aegypti and Aedes albopictus, which are important vectors of dengue hemorrhagic fever and yellow fever in humans. We describe applications of post-PCR techniques, re- striction fragment length polymorphism (RFLP) and single-strand conformation polymorphism (SSCP) to classify these two clades of Aedes densoviruses isolated from different origins. These methods are simple and rapid and are applicable to identify other groups of densoviruses isolated from biological samples.
- Medically important mosquitoes in the rubber plantation belt of central Kerala, India.
Jomon K V , Valamparampil T T Medically important mosquitoes in the rubber plantation belt of central Kerala, India. [Journal Article, Research Support, Non-U.S. Gov't]Southeast Asian J Trop Med Public Health 2014 Jul; 45(4):796-800.AbstractAggregator Full TextEntomological surveys were carried out in the rubber plantation belt of Kerala to record mosquito fauna. Samples were collected from 23 randomly selected localities using standard methods for a period of three years, from Feb- ruary 2008 to January 2011. Thirty-two species belonging to nine genera: Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Heizmannia, Mansonia, Toxorhynchites, and Uranotaenia were recorded. Many of the recorded species were medically im- portant as potential vectors of dengue fever, chikungunya, Japanese encephalitis, malaria and filariasis.