Ronan Kelly
Retired 2020
Circulation of Japanese Encephalitis Virus in Pigs and Mosquito Vectors within Can Tho City, Vietnam
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne, zoonotic flavivirus causing encephalitis in humans and reproductive disorder in pigs. JEV is present in large parts of Asia, where urbanization is high. Households within and outside Can Tho city, South Vietnam, were selected to monitor circulation of JEV. A nested RT-PCR was established to detect the presence of JEV in mosquitoes whereas sera from pigs belonging to households within the province were analyzed for the presence of antibodies to JEV. A total of 7885 mosquitoes were collected and divided into 352 pools whereof seven were JEV-positive, six of which were collected within the city. Fragments from four pools clustered with JEV genotype III and three with genotype I. Of the 43 pigs sampled inside the city 100% had JEV antibodies. Our study demonstrates exposure to JEV in pigs, and co-circulation of JEV genotype I and III in mosquitoes within an urban environment in South Vietnam. Thus, although JEV has mainly been considered a rural disease, the potential for transmission in urban areas cannot be ignored.
Author Summary
Japanese encephalitis (JE) is a serious disease, especially in children, in large parts of Asia. It is transmitted by mosquitoes and mainly known as a disease in the rural, rice-producing areas in South and Southeast Asia. Here, the authors show that of 43 pigs sampled in Can Tho city, South Vietnam, all had antibodies to JE virus (JEV), and since some of these were born in the city, they must have been infected within the urban area. Mosquitoes were collected during night at households both in the city and in a rural area, using traps that attract mosquitoes with light. The mosquitoes were analyzed to see if they had JEV in them. Two different types of JEV were found in mosquito samples collected at urban households. One of these, genotype I, has been emerging in Northern Vietnam and was now shown to be circulating together with the older genotype III. These findings suggest a risk of JEV transmission from pigs to humans in urban areas, or in other words, that JE should not be regarded as a rural disease only.
Citation: Lindahl JF, St?hl K, Chirico J, Boqvist S, Thu HTV, et al. (2013) Circulation of Japanese Encephalitis Virus in Pigs and Mosquito Vectors within Can Tho City, Vietnam. PLoS Negl Trop Dis 7(4): e2153. doi:10.1371/journal.pntd.0002153
Editor: Michael J. Turell, United States Army Medical Research Institute of Infectious Diseases, United States of America
Received: October 2, 2012; Accepted: February 26, 2013; Published: April 4, 2013
Copyright: ? 2013 Lindahl et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was supported by Swedish International Development Cooperation Agency/Department of Research Cooperation (Sida/SAREC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
full paper at; http://www.plosntds.org/article/inf...ra+-+Neglected+Tropical+Diseases+New+Articles)
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne, zoonotic flavivirus causing encephalitis in humans and reproductive disorder in pigs. JEV is present in large parts of Asia, where urbanization is high. Households within and outside Can Tho city, South Vietnam, were selected to monitor circulation of JEV. A nested RT-PCR was established to detect the presence of JEV in mosquitoes whereas sera from pigs belonging to households within the province were analyzed for the presence of antibodies to JEV. A total of 7885 mosquitoes were collected and divided into 352 pools whereof seven were JEV-positive, six of which were collected within the city. Fragments from four pools clustered with JEV genotype III and three with genotype I. Of the 43 pigs sampled inside the city 100% had JEV antibodies. Our study demonstrates exposure to JEV in pigs, and co-circulation of JEV genotype I and III in mosquitoes within an urban environment in South Vietnam. Thus, although JEV has mainly been considered a rural disease, the potential for transmission in urban areas cannot be ignored.
Author Summary
Japanese encephalitis (JE) is a serious disease, especially in children, in large parts of Asia. It is transmitted by mosquitoes and mainly known as a disease in the rural, rice-producing areas in South and Southeast Asia. Here, the authors show that of 43 pigs sampled in Can Tho city, South Vietnam, all had antibodies to JE virus (JEV), and since some of these were born in the city, they must have been infected within the urban area. Mosquitoes were collected during night at households both in the city and in a rural area, using traps that attract mosquitoes with light. The mosquitoes were analyzed to see if they had JEV in them. Two different types of JEV were found in mosquito samples collected at urban households. One of these, genotype I, has been emerging in Northern Vietnam and was now shown to be circulating together with the older genotype III. These findings suggest a risk of JEV transmission from pigs to humans in urban areas, or in other words, that JE should not be regarded as a rural disease only.
Citation: Lindahl JF, St?hl K, Chirico J, Boqvist S, Thu HTV, et al. (2013) Circulation of Japanese Encephalitis Virus in Pigs and Mosquito Vectors within Can Tho City, Vietnam. PLoS Negl Trop Dis 7(4): e2153. doi:10.1371/journal.pntd.0002153
Editor: Michael J. Turell, United States Army Medical Research Institute of Infectious Diseases, United States of America
Received: October 2, 2012; Accepted: February 26, 2013; Published: April 4, 2013
Copyright: ? 2013 Lindahl et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was supported by Swedish International Development Cooperation Agency/Department of Research Cooperation (Sida/SAREC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
full paper at; http://www.plosntds.org/article/inf...ra+-+Neglected+Tropical+Diseases+New+Articles)