Human exposure to zoonotic malaria vectors in village, farm and forest habitats in Sabah, Malaysian Borneo

Rebecca Brown and Chua, Tock Hing and Kimberly Fornace and Chris Drakeley and Indra Vythilingam and Heather M. Ferguson (2020) Human exposure to zoonotic malaria vectors in village, farm and forest habitats in Sabah, Malaysian Borneo. PLOS NEGLECTED TROPICAL DISEASES. pp. 1-18.

[img]
Preview
Text
Human exposure to zoonotic malaria vectors in village, farm and forest habitats in Sabah, Malaysian Borneo.pdf

Download (76kB) | Preview
[img]
Preview
Text
Human exposure to zoonotic malaria vectors in village, farm and forest habitats in Sabah, Malaysian Borneo1.pdf

Download (1MB) | Preview

Abstract

The zoonotic malaria parasite, Plasmodium knowlesi, is now a substantial public health problem in Malaysian Borneo. Current understanding of P. knowlesi vector bionomics and ecology in Sabah comes from a few studies near the epicentre of human cases in one district, Kudat. These have incriminated Anopheles balabacensis as the primary vector, and suggest that human exposure to vector biting is peri-domestic as well as in forest environments. To address the limited understanding of vector ecology and human exposure risk outside of Kudat, we performed wider scale surveillance across four districts in Sabah with confirmed transmission to investigate spatial heterogeneity in vector abundance, diversity and infection rate. Entomological surveillance was carried out six months after a cross-sectional survey of P. knowlesi prevalence in humans throughout the study area; providing an opportunity to investigate associations between entomological indicators and infection. Human-landing catches were performed in peri-domestic, farm and forest sites in 11 villages (3–4 per district) and paired with estimates of human P. knowlesi exposure based on seroprevalence. Anopheles balabacensis was present in all districts but only 6/11 villages. The mean density of An. balabacensis was relatively low, but significantly higher in farm (0.094/ night) and forest (0.082/night) than peri-domestic areas (0.007/night). Only one An. balabacensis (n = 32) was infected with P. knowlesi. Plasmodium knowlesi sero-positivity in people was not associated with An. balabacensis density at the village-level however post hoc analyses indicated the study had limited power to detect a statistical association due low vector density. Wider scale sampling revealed substantial heterogeneity in vector density and distribution between villages and districts. Vector-habitat associations predicted from this larger-scale surveillance differed from those inferred from smaller-scale studies in Kudat; highlighting the importance of local ecological context. Findings highlight potential trade-offs between maximizing temporal versus spatial breadth when designing entomological surveillance; and provide baseline entomological and epidemiological data to inform future studies of entomological risk factors for human P. knowlesi infection.

Item Type: Article
Keyword: zoonotic malaria vectors, village, farm, forest, habitats
Subjects: R Medicine > R Medicine (General)
?? RA0421 ??
Department: FACULTY > Faculty of Medicine and Health Sciences
Depositing User: SITI AZIZAH BINTI IDRIS -
Date Deposited: 30 Oct 2020 08:50
Last Modified: 30 Oct 2020 08:50
URI: https://eprints.ums.edu.my/id/eprint/26223

Actions (login required)

View Item View Item