Japanese encephalitis in Sri Lanka: comparison of vector and virus ecology in different agro-climatic areas

Peiris, Jsm; Amerasinghe, Felix P.; Arunagiri, C. K.; Perera, L. P.; Karunaratne, S.H.P.P.; Ratnayake, C.B.; Kulatilaka, T.A.; Abeysinghe, M.R.N.

doi:10.1016/0035-9203(93)90080-a

Cited by 67 publications

(61 citation statements)

References 4 publications

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“…8 The extended period of seroconversion observed in pigs in the NPA may be similar to the pattern of transmission in some parts of Sri Lanka, where asynchronous infections occur in pigs, and transmission to humans is rare, compared to other regions where synchronous infections in pigs leads to epidemics of JE in humans. 25 Additionally, Ritchie and others suggested that it was the proximity of domestic pigs, people and mosquitoes that contributed to the intense JE virus activity on Badu Island in 1995. 26 On Badu Island, domestic pigs were kept by approximately 50% of residences, usually within 50 m of houses.…”

Section: Resultsmentioning

confidence: 99%

Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

Hurk

Johansen²,

Zborowski³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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Abstract. In response to an outbreak of Japanese encephalitis (JE) virus on Cape York Peninsula, Australia, in 1998, mosquitoes were collected using CO 2 and octenol-baited Centers for Disease Control and Prevention light traps. A total of 35,235 adult mosquitoes, comprising 31 species, were processed for virus isolation. No isolates of JE virus were recovered from these mosquitoes. However, 18 isolates of Kokobera virus, another flavivirus were obtained from Culex annulirostris. Twelve isolates were from western Cape York (minimum infection rate (MIR) of 0.61: 1,000 mosquitoes) and 6 were from the Northern Peninsula Area (MIR of 1.0:1,000). Potential explanations for the failure to detect JE virus in mosquitoes collected from Cape York Peninsula include the timing of collections, the presence of alternative bloodmeal hosts, differences in pig husbandry, asynchronous porcine seroconversion, and the presence of other flaviviruses.

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Section: Resultsmentioning

confidence: 99%

Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

Hurk

Johansen²,

Zborowski³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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“…tritaeniorhynchus for higher elevations, which is consistent with literature reports that Cx. tritaeniorhynchus is infrequently collected above 1,000 m in elevation (Peiris et al, 1993;Pandey et al, 2003). The highest collection site in the ROK occurred at 517 m and the model approaches zero probability of occurrence at approximately 600 m and above (Fig.…”

Section: Discussionmentioning

confidence: 99%

Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea

et al. 2010

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Abstract. Over 35,000 cases of Japanese encephalitis (JE) are reported worldwide each year. Culex tritaeniorhynchus is the primary vector of the JE virus, while wading birds are natural reservoirs and swine amplifying hosts. As part of a JE risk analysis, the ecological niche modeling programme, Maxent, was used to develop a predictive model for the distribution of Cx. tritaeniorhynchus in the Republic of Korea, using mosquito collection data, temperature, precipitation, elevation, land cover and the normalized difference vegetation index (NDVI). The resulting probability maps from the model were consistent with the known environmental limitations of the mosquito with low probabilities predicted for forest covered mountains. July minimum temperature and land cover were the most important variables in the model. Elevation, summer NDVI (July-September), precipitation in July, summer minimum temperature (May-August) and maximum temperature for fall and winter months also contributed to the model. Comparison of the Cx. tritaeniorhynchus model to the distribution of JE cases in the Republic of Korea from 2001 to 2009 showed that cases among a highly vaccinated Korean population were located in high-probability areas for Cx. tritaeniorhynchus. No recent JE cases were reported from the eastern coastline, where higher probabilities of mosquitoes were predicted, but where only small numbers of pigs are raised. The geographical distribution of reported JE cases corresponded closely with the predicted high-probability areas for Cx. tritaeniorhynchus, making the map a useful tool for health risk analysis that could be used for planning preventive public health measures.

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“…As such, pigs are considered to be the main amplification host of JEV. Considering that synchronous infection of pigs has led to significant transmission of JEV to humans (33), targeting the amplifying host is a rational strategy for control and prevention of human cases. The live-inactivated vaccine is not recommended for piglets less than 6 months of age due to neutralization by maternal antibodies, but most pigs live only up to 6 to 8 months before they are slaughtered (13).…”

Section: Japanese Encephalitis Virus (Jev) Is a Member Of The Genusmentioning

confidence: 99%

Delayed Cytosolic Exposure of Japanese Encephalitis Virus Double-Stranded RNA Impedes Interferon Activation and Enhances Viral Dissemination in Porcine Cells

Espada-Murao

Morita

2011

J Virol

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Interferon is a principal component of the host antiviral defense system. In this study, abortive focus formation by Japanese encephalitis virus (JEV) in primate cells was accompanied by early interferon induction, while productive focus formation in porcine cells was associated with a late interferon response. Neutralization antibodies against interferon relieved the restricted infection in primate cells, and increasingly larger foci were generated as treatment with exogenous interferon was delayed, thereby establishing a solid correlation between interferon response and viral dissemination. However, delayed interferon induction in JEV-infected porcine cells occurred in the absence of active inhibition by the virus. We further demonstrated that JEV mediates interferon activation through double-stranded RNA and cytosolic pattern recognition receptors. Immunofluorescence and subcellular fractionation studies revealed that double-stranded RNA is concealed in intracellular membranes at an early phase of infection but eventually appears in the cytosol at later periods, which could then allow detection by cytosolic pattern recognition receptors. Interestingly, cytosolic exposure of double-stranded RNA was delayed in porcine cells compared to primate cells, independent of total double-stranded RNA levels and in correlation with the timing of the interferon response. Furthermore, when double-stranded RNA was artificially introduced into the cytosol of porcine cells, more rapid and robust interferon activation was triggered than in viral infection. Thus, cytosolic exposure of JEV double-stranded RNA is imperative for interferon induction, but in cell lines (e.g., porcine cells) with delayed emergence of cytosolic double-stranded RNA, the interferon response is late and viral dissemination is consequently enhanced.

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Japanese encephalitis in Sri Lanka: comparison of vector and virus ecology in different agro-climatic areas

Cited by 67 publications

References 4 publications

Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea

Delayed Cytosolic Exposure of Japanese Encephalitis Virus Double-Stranded RNA Impedes Interferon Activation and Enhances Viral Dissemination in Porcine Cells

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