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PloS One 2015Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change.
METHODOLOGY
A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December 2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines.
PRINCIPAL FINDINGS
We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies.
CONCLUSION
Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant.
Topics: Animals; Climate Change; Dengue; Elephantiasis, Filarial; Encephalitis, Japanese; Humans; Insect Vectors; Insecta; Leishmaniasis, Visceral; Malaria; Nepal
PubMed: 26086887
DOI: 10.1371/journal.pone.0129869 -
Human Vaccines & Immunotherapeutics 2015Japanese encephalitis virus (JEV), a leading cause of Japanese encephalitis (JE) in children and adults, is a major public health problem in Asian countries. This study... (Meta-Analysis)
Meta-Analysis Review
Japanese encephalitis virus (JEV), a leading cause of Japanese encephalitis (JE) in children and adults, is a major public health problem in Asian countries. This study reports a meta-analysis of the immunogenicity and safety of vaccines used to protect infants or children from JE. Three types of JE vaccine were examined, namely, Japanese encephalitis live-attenuated vaccine (JEV-L), Japanese encephalitis inactivated vaccine (Vero cell) (JEV-I(Vero)), and Japanese encephalitis inactivated vaccine (primary hamster kidney cell) (JEV-I(PHK)). These vaccines are used to induce fundamental immunity against JE; however, few studies have compared their immunogenicity and safety in infants and young children less than 2 years of age. Data were obtained by searching 5 databases: Web of Science, PubMed, China National Knowledge Infrastructure, the China Wanfang database, and the Cochrane database. Fifteen articles were identified and scored using the Jadad score for inclusion in the meta-analysis. Random effect models were used to calculate the pooled seroconversion rate and adverse reaction rate when tests for heterogeneity were significant. The results showed that the pooled seroconversion rate for JEV-I(PHK) (62.23%) was lower than that for JEV-I(Vero) (86.49%) and JEV-L (83.52%), and that the pooled adverse reaction rate for JEV-L (18.09%) was higher than that for JEV-I(PHK) (10.08%) and JEV-I(Vero) (12.49%). The pooled relative risk was then calculated to compare the seroconversion and adverse reaction rates. The results showed that JEV-I(Vero) and JEV-L were more suitable than JEV-I(PHK) for inducing fundamental immunity to JE in infants and children less than 2 years of age.
Topics: Antibodies, Viral; Asia; Drug-Related Side Effects and Adverse Reactions; Encephalitis, Japanese; Humans; Japanese Encephalitis Vaccines; Pacific Islands; Vaccines, Attenuated; Vaccines, Inactivated
PubMed: 25915588
DOI: 10.1080/21645515.2015.1011996 -
PLoS Neglected Tropical Diseases Mar 2015Japanese encephalitis virus (JEV) is an important cause of encephalitis in most of Asia, with high case fatality rates and often significant neurologic sequelae among... (Review)
Review
BACKGROUND
Japanese encephalitis virus (JEV) is an important cause of encephalitis in most of Asia, with high case fatality rates and often significant neurologic sequelae among survivors. The epidemiology of JE in the Philippines is not well defined. To support consideration of JE vaccine for introduction into the national schedule in the Philippines, we conducted a systematic literature review and summarized JE surveillance data from 2011 to 2014.
METHODS
We conducted searches on Japanese encephalitis and the Philippines in four databases and one library. Data from acute encephalitis syndrome (AES) and JE surveillance and from the national reference laboratory from January 2011 to March 2014 were tabulated and mapped.
RESULTS
We identified 29 published reports and presentations on JE in the Philippines, including 5 serologic surveys, 18 reports of clinical cases, and 8 animal studies (including two with both clinical cases and animal data). The 18 clinical studies reported 257 cases of laboratory-confirmed JE from 1972 to 2013. JE virus (JEV) was the causative agent in 7% to 18% of cases of clinical meningitis and encephalitis combined, and 16% to 40% of clinical encephalitis cases. JE predominantly affected children under 15 years of age and 6% to 7% of cases resulted in death. Surveillance data from January 2011 to March 2014 identified 73 (15%) laboratory-confirmed JE cases out of 497 cases tested.
SUMMARY
This comprehensive review demonstrates the endemicity and extensive geographic range of JE in the Philippines, and supports the use of JE vaccine in the country. Continued and improved surveillance with laboratory confirmation is needed to systematically quantify the burden of JE, to provide information that can guide prioritization of high risk areas in the country and determination of appropriate age and schedule of vaccine introduction, and to measure the impact of preventive measures including immunization against this important public health threat.
Topics: Adolescent; Antibodies, Viral; Child; Child, Preschool; Encephalitis Virus, Japanese; Encephalitis, Japanese; Female; Humans; Infant; Japanese Encephalitis Vaccines; Male; Philippines; Public Health; Seroepidemiologic Studies; Vaccination
PubMed: 25794009
DOI: 10.1371/journal.pntd.0003630 -
Human Vaccines & Immunotherapeutics 2014A number of Japanese encephalitis (JE) vaccines have been used for preventing Japanese encephalitis around the world. We here reviewed the immunogenicity and safety of... (Review)
Review
A number of Japanese encephalitis (JE) vaccines have been used for preventing Japanese encephalitis around the world. We here reviewed the immunogenicity and safety of the currently available Japanese encephalitis vaccines. We searched Pubmed, Embase, Web of Science, the Cochrane Library and other online databases up to March 25, 2014 for studies focusing on currently used JE vaccines in any language. The primary outcomes were the seroconversion rate against JEV and adverse events. Meta-analysis was performed for the primary outcome when available. A total of 51 articles were included. Studies were grouped on the basic types of vaccines. This systematic review led to 2 aspects of the conclusions. On one hand, all the currently available JE vaccines are safe and effective. On the other hand, the overall of JE vaccine evaluation is disorganized, the large variation in study designs, vaccine types, schedules, doses, population and few hand-to-hand trails, make direct comparisons difficult. In order to make a more evidence-based decision on optimizing the JE vaccine, it is warranted to standardize the JE vaccine evaluation research.
Topics: Animals; Clinical Trials as Topic; Humans; Japanese Encephalitis Vaccines; Vaccination
PubMed: 25668666
DOI: 10.4161/21645515.2014.980197 -
PLoS Neglected Tropical Diseases Oct 2014Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curtains (ITCs) and insecticide-treated house screening (ITS) against Chagas disease, cutaneous and visceral leishmaniasis, dengue, human African trypanosomiasis, Japanese encephalitis, lymphatic filariasis and onchocerciasis.
METHODS
MEDLINE, EMBASE, LILACS and Tropical Disease Bulletin databases were searched using intervention, vector- and disease-specific search terms. Cluster or individually randomised controlled trials, non-randomised trials with pre- and post-intervention data and rotational design studies were included. Analysis assessed the efficacy of ITNs, ITCs or ITS versus no intervention. Meta-analysis of clinical data was performed and percentage reduction in vector density calculated.
RESULTS
Twenty-one studies were identified which met the inclusion criteria. Meta-analysis of clinical data could only be performed for four cutaneous leishmaniasis studies which together showed a protective efficacy of ITNs of 77% (95%CI: 39%-91%). Studies of ITC and ITS against cutaneous leishmaniasis also reported significant reductions in disease incidence. Single studies reported a high protective efficacy of ITS against dengue and ITNs against Japanese encephalitis. No studies of Chagas disease, human African trypanosomiasis or onchocerciasis were identified.
CONCLUSION
There are likely to be considerable collateral benefits of ITN roll out on cutaneous leishmaniasis where this disease is co-endemic with malaria. Due to the low number of studies identified, issues with reporting of entomological outcomes, and few studies reporting clinical outcomes, it is difficult to make strong conclusions on the effect of ITNs, ITCs or ITS on other VBDs and therefore further studies be conducted. Nonetheless, it is clear that insecticide-treated materials such as ITNs have the potential to reduce pathogen transmission and morbidity from VBDs where vectors enter houses.
Topics: Animals; Arthropod Vectors; Dengue; Elephantiasis, Filarial; Encephalitis, Japanese; Humans; Immunologic Tests; Insecticide-Treated Bednets; Insecticides; Leishmaniasis; Malaria; Mosquito Control
PubMed: 25299481
DOI: 10.1371/journal.pntd.0003228 -
The American Journal of Tropical... May 2014Mosquito-borne viruses are a major public health threat, but their incubation periods are typically uncited, non-specific, and not based on data. We systematically... (Review)
Review
Mosquito-borne viruses are a major public health threat, but their incubation periods are typically uncited, non-specific, and not based on data. We systematically review the published literature on six mosquito-borne viruses selected for their public health importance: chikungunya, dengue, Japanese encephalitis, Rift Valley fever, West Nile, and yellow fever viruses. For each, we identify the literature's consensus on the incubation period, evaluate the evidence for this consensus, and provide detailed estimates of the incubation period and distribution based on published experimental and observational data. We abstract original data as doubly interval-censored observations. Assuming a log-normal distribution, we estimate the median incubation period, dispersion, 25th and 75th percentiles by maximum likelihood. We include bootstrapped 95% confidence intervals for each estimate. For West Nile and yellow fever viruses, we also estimate the 5th and 95th percentiles of their incubation periods.
Topics: Alphavirus Infections; Animals; Chikungunya Fever; Chikungunya virus; Culicidae; Dengue; Dengue Virus; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Infectious Disease Incubation Period; Public Health; Rift Valley Fever; Rift Valley fever virus; West Nile Fever; West Nile virus; Yellow Fever; Yellow fever virus
PubMed: 24639305
DOI: 10.4269/ajtmh.13-0403 -
PLoS Neglected Tropical Diseases 2013Dengue poses a substantial economic and disease burden in Southeast Asia (SEA). Quantifying this burden is critical to set policy priorities and disease-control... (Review)
Review
BACKGROUND
Dengue poses a substantial economic and disease burden in Southeast Asia (SEA). Quantifying this burden is critical to set policy priorities and disease-control strategies.
METHODS AND FINDINGS
We estimated the economic and disease burden of dengue in 12 countries in SEA: Bhutan, Brunei, Cambodia, East-Timor, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Viet Nam. We obtained reported cases from multiple sources--surveillance data, World Health Organization (WHO), and published studies--and adjusted for underreporting using expansion factors from previous literature. We obtained unit costs per episode through a systematic literature review, and completed missing data using linear regressions. We excluded costs such as prevention and vector control, and long-term sequelae of dengue. Over the decade of 2001-2010, we obtained an annual average of 2.9 million (m) dengue episodes and 5,906 deaths. The annual economic burden (with 95% certainty levels) was US$950m (US$610m-US$1,384m) or about US$1.65 (US$1.06-US$2.41) per capita. The annual number of disability-adjusted life years (DALYs), based on the original 1994 definition, was 214,000 (120,000-299,000), which is equivalent to 372 (210-520) DALYs per million inhabitants.
CONCLUSION
Dengue poses a substantial economic and disease burden in SEA with a DALY burden per million inhabitants in the region. This burden is higher than that of 17 other conditions, including Japanese encephalitis, upper respiratory infections, and hepatitis B.
Topics: Asia, Southeastern; Cost of Illness; Dengue; Health Care Costs; Humans; Survival Analysis
PubMed: 23437406
DOI: 10.1371/journal.pntd.0002055 -
The National Medical Journal of India 2012Seasonal outbreaks of acute encephalitis syndrome (AES) occur with striking regularity in India and lead to substantial mortality. Several viruses, endemic in many parts... (Review)
Review
BACKGROUND
Seasonal outbreaks of acute encephalitis syndrome (AES) occur with striking regularity in India and lead to substantial mortality. Several viruses, endemic in many parts of India, account for AES. Although Japanese encephalitis virus (JEV) is a key aetiological agent for AES in India, and has attracted countrywide attention, many recent studies suggest that enteroviruses and rhabdoviruses might account for outbreaks of AES. We did a systematic review of published studies to understand the changing landscape of AES in India.
DATA SOURCES
Electronic databases (PubMed, Web of Science and BIOSIS) from the start of the database to 2010. We also hand-searched journals and screened reference lists of original articles, reviews and book chapters to identify additional studies.
STUDY SELECTION
We included studies only on humans and from three time-periods: pre-1975, 1975-1999 and 2000-2010.
DATA EXTRACTION
Independent, duplicate data extraction and quality assessment were conducted. Data extracted included study characteristics, type of study and aetiological agent identified.
DATA SYNTHESIS
Of the 749 unique published articles screened, 57 studies met the inclusion criteria (35 outbreak investigations and 22 surveillance studies).
RESULTS
While most studies from 1975 to 1999 identified JEV as the main cause of AES, many studies published after 2000 identified Chandipura and enteroviruses as the most common agents, in both outbreaks and surveillance studies. Overall, a positive yield with respect to identification of aetiological agents was higher in outbreak investigations as compared to surveillance studies.
CONCLUSION
The landscape of AES in India has changed in the previous decade, and both outbreak investigations and surveillance studies have increasingly reported non-JEV aetiologies. Because of these findings, there is a need to explore additional strategies to prevent AES beyond vector control and JEV vaccination.
Topics: Acute Disease; Encephalitis; Encephalitis, Japanese; Enterovirus; Humans; India; Vesiculovirus
PubMed: 23278779
DOI: No ID Found -
Vaccine Jan 2013China is the most populous country in the world, with an annual birth cohort of approximately 16 million, requiring an average of 500 million vaccine doses administered... (Review)
Review
Systematic review of reporting rates of adverse events following immunization: an international comparison of post-marketing surveillance programs with reference to China.
BACKGROUND
China is the most populous country in the world, with an annual birth cohort of approximately 16 million, requiring an average of 500 million vaccine doses administered annually. In China, over 30 domestic and less than 10 overseas vaccine manufacturers supply over 60 licensed vaccine products, representing a growing vaccine market mainly due to recent additions to the national immunization schedule, but data on post-marketing surveillance for adverse events following immunization (AEFI) are sparse.
OBJECTIVES
To compare reporting rates for various categories of AEFI from China with other routine post-marketing surveillance programs internationally.
METHODS
Systematic review of published studies reporting rates of AEFI by vaccine, category of reaction and age from post-marketing surveillance systems in English and Chinese languages.
RESULTS
Overall AEFI reporting rates (all vaccines, all ages) in Chinese studies were consistent with those from similar international studies elsewhere, but there was substantial heterogeneity in regional reporting rates in China (range 2.3-37.8/100,000 doses). The highest AEFI reporting rates were for diphtheria-tetanus-pertussis whole-cell (DTwP) and acellular (DTaP) vaccines (range 3.3-181.1/100,000 doses for DTwP; range 3.5-92.6/100,000 doses for DTaP), with higher median rates for DTwP than DTaP, and higher than expected rates for DTaP vaccine. Similar higher rates for DTwP and DTaP containing vaccines, and relatively lower rates for vaccines against hepatitis B virus, poliovirus, and Japanese encephalitis virus were found in China and elsewhere in the world.
CONCLUSIONS
Overall AEFI reporting rates in China were consistent with similar post-marketing surveillance systems in other countries. Sources of regional heterogeneity in AEFI reporting rates, and their relationships to differing vaccine manufacturers versus differing surveillance practices, require further exploration.
Topics: Adverse Drug Reaction Reporting Systems; Bacterial Vaccines; Child; Child, Preschool; China; Humans; Immunization; Immunization Schedule; Infant; Infant, Newborn; Product Surveillance, Postmarketing; Viral Vaccines
PubMed: 23200940
DOI: 10.1016/j.vaccine.2012.11.051 -
PloS One 2012An increasing use of point of care diagnostic tests that exclude malaria, coupled with a declining malaria burden in many endemic countries, is highlighting the lack of... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
An increasing use of point of care diagnostic tests that exclude malaria, coupled with a declining malaria burden in many endemic countries, is highlighting the lack of ability of many health systems to manage other causes of febrile disease. A lack of knowledge of distribution of these pathogens, and a lack of screening and point-of-care diagnostics to identify them, prevents effective management of these generally treatable contributors to disease burden. While prospective data collection is vital, an untapped body of knowledge already exists in the published health literature.
METHODS
Focusing on the Mekong region of Southeast Asia, published data from 1986 to 2011 was screened to for frequency of isolation of pathogens implicated in aetiology of non-malarial febrile illness. Eligibility criteria included English-language peer-reviewed studies recording major pathogens for which specific management is likely to be warranted. Of 1,252 identified papers, 146 met inclusion criteria and were analyzed and data mapped.
RESULTS
Data tended to be clustered around specific areas where research institutions operate, and where resources to conduct studies are greater. The most frequently reported pathogen was dengue virus (n = 70), followed by Orientia tsutsugamushi and Rickettsia species (scrub typhus/murine typhus/spotted fever group n = 58), Leptospira spp. (n = 35), Salmonella enterica serovar Typhi and Paratyphi (enteric fever n = 24), Burkholderia pseudomallei (melioidosis n = 14), and Japanese encephalitis virus (n = 18). Wide tracts with very little published data on aetiology of fever are apparent.
DISCUSSION AND CONCLUSIONS
This mapping demonstrates a very heterogeneous distribution of information on the causes of fever in the Mekong countries. Further directed data collection to address gaps in the evidence-base, and expansion to a global database of pathogen distribution, is readily achievable, and would help define wider priorities for research and development to improve syndromic management of fever, prioritize diagnostic development, and guide empirical therapy.
Topics: Asia, Southeastern; Fever; Geography; Humans
PubMed: 22970193
DOI: 10.1371/journal.pone.0044269