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Parasites & Vectors Aug 2022The entomological inoculation rate (EIR) is one of the key indices used to evaluate malaria transmission and vector control interventions. One of the components of the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The entomological inoculation rate (EIR) is one of the key indices used to evaluate malaria transmission and vector control interventions. One of the components of the EIR is the sporozoite rate in Anopheles vectors. A systematic review and meta-analysis was performed to identify the prevalence of Plasmodium spp. in field-collected Anopheles species across Thailand.
METHODS
This systematic review was registered under the PROSPERO number CRD42021297255. Studies that focused on the identification of Plasmodium spp. in Anopheles mosquitoes were identified from the electronic databases PubMed, Web of Science, and Scopus. The quality of the identified studies was determined using the Strengthening the Reporting of Observational Studies in Epidemiology approach. The proportion of Anopheles mosquitoes collected, Anopheles vectors for Plasmodium species, and specificity of Anopheles vectors for Plasmodium species were analyzed. The pooled prevalence of Plasmodium species among the primary vectors (Anopheles dirus, Anopheles minimus, and Anopheles maculatus) was estimated using the random-effects model.
RESULTS
Of the 1113 studies identified, 31 were included in the syntheses. Of the 100,910 Anopheles mosquitoes identified for species and sibling species, An. minimus (40.16%), An. maculatus (16.59%), and Anopheles epiroticus (9.18%) were the most prevalent Anopheles species. Of the 123,286 Anopheles mosquitoes identified, 566 (0.46%) were positive for Plasmodium species. The highest proportions of Plasmodium species were identified in Anopheles hodgkini (2/6, 33.3%), Anopheles nigerrimus (2/24, 8.33%), Anopheles balabacensis (4/84, 4.76%), An. dirus (114/4956, 2.3%), Anopheles annularis (16/852, 1.88%), Anopheles kochi (8/519, 1.54%), Anopheles vagus (3/215, 1.4%), and Anopheles baimaii (1/86, 1.16%). The pooled prevalence of Plasmodium species identified in the main Anopheles vectors was 0.4% of that of Plasmodium species identified in An. dirus was 2.1%, that of Plasmodium species identified in An. minimus was 0.4%, and that of Plasmodium species identified in An. maculatus was 0.4%.
CONCLUSIONS
We found a low prevalence of Plasmodium infection in Anopheles mosquitoes across Thailand. Therefore, the use of EIR to determine the impact of vector control intervention on malaria parasite transmission and elimination in Thailand must be undertaken with caution, as a large number of Anopheles specimens may be required.
Topics: Animals; Anopheles; Malaria; Mosquito Vectors; Plasmodium; Prevalence; Thailand
PubMed: 35933389
DOI: 10.1186/s13071-022-05397-2 -
Journal of Infection and Public Health Sep 2022Japanese encephalitis (JE) is a viral zoonotic disease that has been found in several countries of Asia and is responsible for high mortality and morbidity of men and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Japanese encephalitis (JE) is a viral zoonotic disease that has been found in several countries of Asia and is responsible for high mortality and morbidity of men and animals in rural and sub-urban endemic areas due to the virus re-circulation among diverse hosts and vectors. The present study estimates the prevalence of the JE virus in the vector and animal population of the Asian continent using a systematic review and meta-analysis.
METHODS
The Cochran collaborators' Preferred Reporting Items for Systematic Reviews and Meta-Analysis [PRISMA] guidelines were used for systematic review and meta-analysis. The heterogeneity was observed in meta-regression analysis due to several factors including region, species, and different diagnostic assays used in various studies. Thus we did sensitivity and subgroup analysis.
RESULTS
The prevalence of the JE virus was calculated using a total sample size of 47,391. Subgroup analysis revealed the JE virus prevalence of 39% in the Southeast Asia region, followed by East Asia with 35% and South Asia with 15% prevalence. Hence, the overall pooled prevalence of the JE virus was 26% in the Asian continent.
CONCLUSIONS
The highest proportion of infection was found in pigs amongst all animals, reinforcing the fact that they can be used as sentinels to predict outbreaks in humans. The findings of this study will enable researchers and policymakers in better understanding the disease's spatial and temporal distribution, as well as in creating and implementing location-specific JE prevention and control measures.
Topics: Animals; Culicidae; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Male; Mosquito Vectors; Prevalence; Swine
PubMed: 35914358
DOI: 10.1016/j.jiph.2022.07.010 -
PLoS Neglected Tropical Diseases Jul 2022Dengue is the world's most prevalent mosquito-borne viral disease. It is endemic in many tropical and subtropical countries and represents a significant global health... (Review)
Review
BACKGROUND
Dengue is the world's most prevalent mosquito-borne viral disease. It is endemic in many tropical and subtropical countries and represents a significant global health burden. The first reports of dengue virus (DENV) circulation in the South West Indian Ocean (SWIO) islands date back to the early 1940s; however, an increase in DENV circulation has been reported in the SWIO in recent years. The aim of this review is to trace the history of DENV in the SWIO islands using available records from the Comoros, Madagascar, Mauritius, Mayotte, Seychelles, and Reunion. We focus in particular on the most extensive data from Reunion Island, highlighting factors that may explain the observed increasing incidence, and the potential shift from one-off outbreaks to endemic dengue transmission.
METHODS
Following the PRISMA guidelines, the literature review focused queried different databases using the keywords "dengue" or "Aedes albopictus" combined with each of the following SWIO islands the Comoros, Madagascar, Mauritius, Mayotte, Seychelles, and Reunion. We also compiled case report data for dengue in Mayotte and Reunion in collaboration with the regional public health agencies in these French territories. References and data were discarded when original sources were not identified. We examined reports of climatic, anthropogenic, and mosquito-related factors that may influence the maintenance of dengue transmission independently of case importation linked to travel.
FINDINGS AND CONCLUSIONS
The first report of dengue circulation in the SWIO was documented in 1943 in the Comoros. Then not until an outbreak in 1976 to 1977 that affected approximately 80% of the population of the Seychelles. DENV was also reported in 1977 to 1978 in Reunion with an estimate of nearly 30% of the population infected. In the following 40-year period, DENV circulation was qualified as interepidemic with sporadic cases. However, in recent years, the region has experienced uninterrupted DENV transmission at elevated incidence. Since 2017, Reunion witnessed the cocirculation of 3 serotypes (DENV-1, DENV-2 and DENV-3) and an increased number of cases with severe forms and deaths. Reinforced molecular and serological identification of DENV serotypes and genotypes circulating in the SWIO as well as vector control strategies is necessary to protect exposed human populations and limit the spread of dengue.
Topics: Aedes; Animals; Disease Outbreaks; Humans; Indian Ocean; Mosquito Vectors; Reunion
PubMed: 35900991
DOI: 10.1371/journal.pntd.0010547 -
Acta Tropica Oct 2022Dengue is classified as an endemic infectious disease, which is transmitted by Aedes mosquitos. Kinetic studies, which monitor the viral load of the disease, have been...
Dengue is classified as an endemic infectious disease, which is transmitted by Aedes mosquitos. Kinetic studies, which monitor the viral load of the disease, have been the mainstay for several decades in humanity's quest to control this disease. Our study aims to systematically evaluate the usage of different timing systems in dengue kinetic studies. A search in nine electronic databases and manual search of reference and citation lists were conducted to find relevant studies. A quality assessment using the National Institute of Health tools for observational cohort and cross-sectional studies was performed. The protocol was registered in PROSPERO with number CRD42018086435. As results, among included 87 studies, 71 studies (81.6%) use a timing system which is based on the day of illness onset, of which, 11 studies designate the day of illness onset as "day 0″ (type 1A) while 60 studies designate it as "day 1″ (type 1B). Only ten articles (11.5%) designate the day of defervescence as "day 0″, the day before and after defervescence as "day -1″ and "day +1″, respectively. Four articles (4.6%) use a timing system based on the day of hospital admission. Lastly, two studies (2.3%) designate the day of hemorrhagic manifestation as "day 0″ and two studies (2.3%) designate the day of pharmacological treatment as "day 1″. Therefore, the timing system which designates the day of illness onset as "day 1″ (type 1B) was most commonly used. Inconsistent definitions of "day 0″ and "day 1″ may lead to disparities in results across the studies and may have a negative impact on treatment guidelines implementation.
Topics: Aedes; Animals; Cohort Studies; Cross-Sectional Studies; Dengue; Dengue Virus; Humans; Kinetics; Mosquito Vectors
PubMed: 35798088
DOI: 10.1016/j.actatropica.2022.106584 -
Nature Communications Jul 2022The cause of malaria transmission has been known for over a century but it is still unclear whether entomological measures are sufficiently reliable to inform policy...
The cause of malaria transmission has been known for over a century but it is still unclear whether entomological measures are sufficiently reliable to inform policy decisions in human health. Decision-making on the effectiveness of new insecticide-treated nets (ITNs) and the indoor residual spraying of insecticide (IRS) have been based on epidemiological data, typically collected in cluster-randomised control trials. The number of these trials that can be conducted is limited. Here we use a systematic review to highlight that efficacy estimates of the same intervention may vary substantially between trials. Analyses indicate that mosquito data collected in experimental hut trials can be used to parameterize mechanistic models for Plasmodium falciparum malaria and reliably predict the epidemiological efficacy of quick-acting, neuro-acting ITNs and IRS. Results suggest that for certain types of ITNs and IRS using this framework instead of clinical endpoints could support policy and expedite the widespread use of novel technologies.
Topics: Animals; Culicidae; Humans; Insecticide-Treated Bednets; Insecticides; Malaria; Mosquito Control; Mosquito Vectors
PubMed: 35790746
DOI: 10.1038/s41467-022-30700-1 -
Frontiers in Public Health 2022Arboviruses are a group of diseases that are transmitted by an arthropod vector. Since they are part of the Neglected Tropical Diseases that pose several public health...
Arboviruses are a group of diseases that are transmitted by an arthropod vector. Since they are part of the Neglected Tropical Diseases that pose several public health challenges for countries around the world. The arboviruses' dynamics are governed by a combination of climatic, environmental, and human mobility factors. Arboviruses prediction models can be a support tool for decision-making by public health agents. In this study, we propose a systematic literature review to identify arboviruses prediction models, as well as models for their transmitter vector dynamics. To carry out this review, we searched reputable scientific bases such as IEE Xplore, PubMed, Science Direct, Springer Link, and Scopus. We search for studies published between the years 2015 and 2020, using a search string. A total of 429 articles were returned, however, after filtering by exclusion and inclusion criteria, 139 were included. Through this systematic review, it was possible to identify the challenges present in the construction of arboviruses prediction models, as well as the existing gap in the construction of spatiotemporal models.
Topics: Animals; Arbovirus Infections; Arboviruses; Arthropod Vectors; Humans; Machine Learning; Models, Statistical; Neglected Diseases; Public Health
PubMed: 35719644
DOI: 10.3389/fpubh.2022.900077 -
Archives of Microbiology Jun 2022The number of arbovirus cases has increased in recent years, demonstrating a need for investing in effective control actions. Among these actions, are strategies using... (Review)
Review
The number of arbovirus cases has increased in recent years, demonstrating a need for investing in effective control actions. Among these actions, are strategies using biological control vectors, a field where Wolbachia pipientis has shown itself as useful. Wolbachia pipientis, an obligatory intracellular Gram-negative bacteria, which parasites arthropods naturally or through laboratory-induced infections, is capable of manipulating the reproduction of its host. A systematic literature review gathering studies on this bacteria over last 10 years (2007-2021) was performed given its important role in the reduction of insect disease vectors. 111 articles were found, from which 78 were used in this study. Information on the Wolbachia biology, mechanism of action and potential for the biological control of insect disease vectors was gathered. The present study may contribute to the knowledge surrounding the bacterium, as well as stimulate the production of other studies with the same theme.
Topics: Animals; Arboviruses; Insect Vectors; Wolbachia
PubMed: 35678877
DOI: 10.1007/s00203-022-02983-x -
International Journal of Environmental... Nov 2023Among several vector control methods commonly used, environmental management is one of the control measures to mitigate dengue in such vulnerable communities. Since... (Review)
Review
Among several vector control methods commonly used, environmental management is one of the control measures to mitigate dengue in such vulnerable communities. Since there is no curative treatment for dengue yet, targeted environmental and ecosystem management is increasingly relevant. Hence, this review was conducted to identify the effectiveness of environmental management intervention strategy to reduce dengue cases. We searched PUBMED, CENTRAL, SCOPUS, Web of Science, CIJE, WHO ICTRP, and ClinicalTrials.gov up to January 2021. A total of 521 articles were screened. Only 16 studies were included in this review. There were 6 studies that applied all three types of environmental management interventions (manipulation, modification and behavior), 8 studies applied two types of interventions (manipulation and behavior) and 2 studies applied one type of intervention (manipulation or behavior). All included studies reported reduction of entomological indices. The studies showed reduction in dengue cases and density of population through environmental interventions. It is recommended for the health authority to incorporate environmental management intervention in dengue control activities and enhanced the community involvement to ensure sustainability with high impact on dengue reduction.
Topics: Animals; Humans; Mosquito Control; Dengue; Ecosystem; Conservation of Natural Resources; Mosquito Vectors; Aedes
PubMed: 35642722
DOI: 10.1080/09603123.2022.2076815 -
Acta Tropica Sep 2022Vector-borne diseases are a major public health problem. Amongst them, dengue, Zika and chikungunya illnesses are increasing their incidence and geographical expansion.... (Review)
Review
Vector-borne diseases are a major public health problem. Amongst them, dengue, Zika and chikungunya illnesses are increasing their incidence and geographical expansion. Since vector control is the main measure to prevent these diseases, this systematic review aims to determine the effectiveness of environmental interventions for the prevention of the transmission of these three diseases, as well as for the reduction of their burden. Experimental studies of environmental management interventions aimed at vector control were included. The outcome variables of interest were disease burden indicators and entomological indicators. Of the 923 references initially retrieved, after discarding those that were duplicated or didn't comply with the inclusion criteria, a total of 7 articles were included. All included studies carried out environmental manipulation interventions and only 1 carried out an environmental modification intervention. Regarding the outcome variables, all used entomological indicators (larval or pupae indices). Of those, pupae indices are better indicators of vector abundance. In 4 out of the 6 studies, there was a statistically significant reduction of the pupae indices related to the elimination of small containers, manipulation of large tanks and cleaning outdoor spaces. These interventions are easy to implement and involve little resources, which acquires special importance regarding areas with limited resources. Although it is assumed that a reduction of mosquitoes would lead to a reduction or the risk of transmission, a little evidence proving this has been published. It would be advisable that, in addition to entomological indicators, epidemiological, environmental and sociodemographic factors would be taken into consideration, bearing in mind that mosquito density is one of the many factors that influence the transmission of these viruses. None of the papers included used disease indicators, not allowing to demonstrate if environmental interventions contribute to reduce disease burden.
Topics: Aedes; Animals; Chikungunya Fever; Dengue; Humans; Mosquito Control; Mosquito Vectors; Pupa; Zika Virus; Zika Virus Infection
PubMed: 35598649
DOI: 10.1016/j.actatropica.2022.106523 -
PLoS Neglected Tropical Diseases May 2022Indoor Residual Spraying (IRS) is one of the interventions to control the vectors of Visceral Leishmaniasis (VL). Different insecticides are used in affected countries,...
Indoor Residual Spraying (IRS) is one of the interventions to control the vectors of Visceral Leishmaniasis (VL). Different insecticides are used in affected countries, also in the Regional Initiative for the Elimination of VL in South-East Asia. This systematic review assesses all available studies analysing the effectiveness of IRS on the key vectors of VL. The systematic review followed PRISMA guidelines, with a broad search strategy, applied to seven key databases. Inclusion criteria were studies focusing on 1) Visceral leishmaniasis 2) Indoor Residual Spraying (IRS) or synonyms, and 3) all primary research methods. 21 studies were included, five cluster randomised controlled trials (cRCTs), one randomised controlled trial (RCT), 11 intervention studies, also included were three modelling studies and one survey. 19 out of 21 included studies were published between 2009 and 2020. 18 of the studies were conducted in the context of the Regional Initiative. Effects of IRS on vector populations are positive, confirmed in terms of effectiveness and by the availability of studies. Deltamethrin and alpha-Cypermethrin reduce total sandfly counts, and/or Phlebotomus argentipes counts by up to 95% with an effect of a minimum of one month. Prolonged effects are not regularly seen. DDT has been used in India only: whereas in the 1990s a good effect could be measured, this effect waned over time. Two intervention studies, embedded in larger programmes in 2019 and 2020, replaced DDT with alpha-Cypermethrin throughout the study. Combinations of different interventions are not systematically researched, however showing some promising results, for example for the combination of IRS and Temephos. Constant monitoring of insecticide resistancies and quality delivery of IRS are confirmed as key issues for programmes. No human transmission data are available to directly relate an effect of IRS-although modelling studies confirm the effect of IRS on human transmission. Concluding, IRS continues to be an effective intervention for Phlebotomus argentipes control. Delivery requires constant monitoring and quality assurance. Further studies need to assess IRS in different geographical areas affected by VL and combinations of interventions.
Topics: Animals; DDT; Disease Progression; Humans; Insect Vectors; Insecticides; Leishmaniasis, Visceral; Phlebotomus; Psychodidae
PubMed: 35587498
DOI: 10.1371/journal.pntd.0010391