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

• Published in: Environment international Vol. 79; pp. 17 - 24
• Main Authors: Tian, Huai-Yu, Bi, Peng, Cazelles, Bernard, Zhou, Sen, Huang, Shan-Qian, Yang, Jing, Pei, Yao, Wu, Xiao-Xu, Fu, Shi-Hong, Tong, Shi-Lu, Wang, Huan-Yu, Xu, Bing
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-06-2015
• Subjects: Animals; China; China - epidemiology; Climate; Culicidae; Culicidae - physiology; Density; Disease Vectors; Diseases; Ecology; Ecosystem; Encephalitis; Encephalitis, Japanese - epidemiology; Encephalitis, Japanese - transmission; Environmental thresholds; Generalized threshold models; Human; Humans; Humidity; Japanese encephalitis; Mathematical models; Mosquito vector; Population Density; Risk Factors; Risk management; Temperature; Thresholds; China; ISEW, Southeast Asia; China, People's Rep; China, People's Rep., Hunan Prov., Changsha; Generalized threshold models; Climate; Environmental thresholds; China; Mosquito vector; Japanese encephalitis
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2015.03.002

Japanese encephalitis (JE) is one of the major vector-borne diseases in Southeast Asia and the Western Pacific region, posing a threat to human health. In rural and suburban areas, traditional rice farming and intensive pig breeding provide an ideal environment for both mosquito development and the transmission of JEV among human beings. Combining surveillance data for mosquito vectors, human JE cases, and environmental conditions in Changsha, China, 2004–2009, generalized threshold models were constructed to project the mosquito and JE dynamics. Temperature and rainfall were found to be closely associated with mosquito density at 1, and 4month lag, respectively. The two thresholds, maximum temperature of 22–23°C for mosquito development and minimum temperature of 25–26°C for JEV transmission, play key roles in the ecology of JEV. The model predicts that, in the upper regime, a 1g/m3 increase in absolute humidity would on average increase human cases by 68–84%. A shift in mosquito species composition in 2007 was observed, and possibly caused by a drought. Effective predictive models could be used in risk management to provide early warnings for potential JE transmission.
•Threshold of maximum temperature, 22–23°C, was detected for mosquito development.•Threshold of minimum temperature, 25–26°C, was detected for JE occurrence.•A 1g/m3 increase in absolute humidity would on average increase human cases by 68–84%.•Climate could result in mosquito species composition shift.