Entomological Investigation of Japanese Encephalitis Vector in Bali, Indonesia

Abstract

Background: Japanese encephalitis (JE), caused by the Japanese encephalitis virus (JEV), is a mosquito-borne disease prevalent in Southeast Asia. Pigs act as amplifying hosts, and their presence influences mosquito population dynamics. This study investigates the relationship between mosquito density and pig population in three regencies of Bali, Indonesia: Jembrana, Badung, and Karangasem.

Method: The research was a cross-sectional study using spot survey method in three regencies in Bali. The samples were all mosquitoes captured in the research locations. Mosquitoes were collected using techniques like human landing catches (HLCs) and animal-baited traps across different ecosystems—urban, forest, and coastal. Data on pig populations were obtained from the Bali Central Bureau of Statistics.

Results: Culex tritaeniorhynchus, Cx. vishnui, and Anopheles vagus were the dominant mosquito species across all regencies. Higher mosquito densities were observed in areas with significant pig populations, such as Negara and Mengwi, suggesting a link between pig farming and mosquito populations. However, some areas with high pig potential, like Rendang, showed lower mosquito densities, indicating the influence of other ecological factors.

Conclusion: The study highlights an observed association between mosquito density and the presence of pig populations, suggesting that livestock may play an important role in areas where Japanese Encephalitis Virus (JEV) transmission is prevalent. Recognizing this pattern could help inform future vector control strategies. Further observational research may be needed to investigate additional environmental conditions that coincide with higher mosquito populations in these regions.

Keywords: Japanese encephalitis; Mosquito density; Pig population; Vector control