How environmental conditions impact mosquito ecology and Japanese encephalitis: An eco-epidemiological approach

Tian, Huaiyu; Bi, Peng; Cazelles, Bernard; Zhou, Sen; Huang, Shanqian; Yang, Jing; Yao, Panpan; Wu, Xiaoxu; Fu, Shihong; Tong, Shilu; Wang, Huanyu; Xu, Bing

doi:10.1016/j.envint.2015.03.002

Cited by 76 publications

(68 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[43] Studies have implicated meteorological conditions and vector populations as critical to the occurrence of JE infection in areas without significant pig populations. [22,44] In Australia, it has been seen that herons and egrets are potential sources from where the vectors may acquire the JEV;[45] such a scenario, though not entirely unlikely in the Indian setting, is probably not a major driver. The proximity of villages and the feral nature of pigs which have been documented to have wide wandering ranges, in combination with extensive vector flight ranges, is likely to drive the intense transmission of JEV infection in children even in the villages without any pig-rearing activities.…”

Section: Discussionmentioning

confidence: 99%

Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

et al. 2017

View full text Add to dashboard Cite

Japanese Encephalitis (JE) has caused repeated outbreaks in endemic pockets of India. This study was conducted in Kushinagar, a highly endemic district, to understand the human-animal-ecosystem interactions, and the drivers that influence disease transmission. Utilizing the ecosystems approach, a cross-sectional, descriptive study, employing mixed methods design was employed. Four villages (two with pig-rearing and two without) were randomly selected from a high, a medium and a low burden (based on case counts) block of Kushinagar. Children, pigs and vectors were sampled from these villages. A qualitative arm was incorporated to explain the findings from the quantitative surveys. All human serum samples were screened for JE-specific IgM using MAC ELISA and negative samples for JE RNA by rRT-PCR in peripheral blood mononuclear cells. In pigs, IgG ELISA and rRT-PCR for viral RNA were used. Of the 242 children tested, 24 tested positive by either rRT-PCR or MAC ELISA; in pigs, 38 out of the 51 pigs were positive. Of the known vectors, Culex vishnui was most commonly isolated across all biotopes. Analysis of 15 blood meals revealed human blood in 10 samples. Univariable analysis showed that gender, religion, lack of indoor residual spraying of insecticides in the past year, indoor vector density (all species), and not being vaccinated against JE in children were significantly associated with JE positivity. In multivariate analysis, only male gender remained as a significant risk factor. Based on previous estimates of symptomatic: asymptomatic cases of JE, we estimate that there should have been 618 cases from Kushinagar, although only 139 were reported. Vaccination of children and vector control measures emerged as major control activities; they had very poor coverage in the studied villages. In addition, lack of awareness about the cause of JE, lack of faith in the conventional medical healthcare system and multiple referral levels causing delay in diagnosis and treatment emerged as factors likely to result in adverse clinical outcomes.

show abstract

Section: Discussionmentioning

confidence: 99%

Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

et al. 2017

View full text Add to dashboard Cite

show abstract

“…However, under dry conditions, mosquito's vector competence might get reduced, because of the diversion of available cellular resources for its own maintenance . In context of natural human infections, increase in humidity has been associated with increased human cases for Japanese encephalitis virus . In view of the fewer studies, demonstrating role of humidity on viral transmission, it is difficult to predict the actual effect of humidity on vector competence.…”

Section: Factors Affecting Vector Competencementioning

confidence: 99%

Impact of transmission cycles and vector competence on global expansion and emergence of arboviruses

2017

View full text Add to dashboard Cite

Arboviruses are transmitted between arthropod vectors and vertebrate host. Arboviral infection in mosquitoes is initiated when a mosquito feeds on a viremic host. Following ingestion of a viremic blood meal by mosquitoes, virus enters midgut along with the blood, infects and replicates in midgut epithelial cells, and then escapes to the hemocoel, from where it disseminates to various secondary organs including salivary glands. Subsequently, when mosquito bites another host, a new transmission cycle is initiated. The midgut and salivary glands act as anatomical barriers to virus infection and escape. These complex interactions between the virus and vector dictate the vector competence. Thus, vector competence reflects the success in overcoming different barriers within the vector. Along with these, other intrinsic factors like midgut microbiota and immune responses, extrinsic factors like temperature and humidity, and genetic factors like vector genotype and viral genotype have been discussed in this review. Recent advancement on novel molecular tools to study vector competence is also included. Different modes of arboviral transmission like horizontal, vertical, and venereal and how these play role in sustenance and emergence of arboviruses in nature are also discussed. These factors can be exploited to reduce the susceptibility of vectors for the viruses, so as to control arboviral diseases to certain extent.

show abstract

“…Absolute humidity is related to longevity, mating, dispersal, and feeding behaviour of mosquitoes. Temperatures within the range 22-34°C increases mosquito density, decreases larval development time and reduces the extrinsic incubation period of the virus in mosquito vectors, affecting potential JEV transmission (Wang et al, 2014;Tian et al, 2015).…”

Section: Environmentmentioning

confidence: 99%

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Japanese encephalitis (JE)

More¹,

Bøtner²,

Butterworth

et al. 2017

EFS2

View full text Add to dashboard Cite

show abstract

How environmental conditions impact mosquito ecology and Japanese encephalitis: An eco-epidemiological approach

Cited by 76 publications

References 50 publications

Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

Impact of transmission cycles and vector competence on global expansion and emergence of arboviruses

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Japanese encephalitis (JE)

Contact Info

Product

Resources

About