Temporal and Geographical Patterns of Pacific Arboviral Vectors on Ebeye, Republic of the Marshall Islands: Insights from a Longitudinal Entomological Study

TL;DR

This study tracks mosquito populations on Ebeye Island to understand patterns and inform better control of arboviruses like dengue and Zika.

Contribution

The study provides new longitudinal data on mosquito species abundance and distribution in the Marshall Islands.

Findings

Aedes aegypti was most prevalent, with higher abundance on Ebeye compared to northern islets.

Aedes albopictus was more common on northern islets, while Culex quinquefasciatus showed similar levels across locations.

Mosquito abundance was influenced by rainfall and human factors like water storage and housing density.

Abstract

Arthropod-borne viruses (arboviruses) such as dengue, chikungunya, Zika, and yellow fever pose significant global health risks, with mosquitoes from the Aedes genus as the primary vectors responsible for human transmission. The Republic of the Marshall Islands (RMI), particularly the urbanized areas of Kwajalein and Majuro atolls, has experienced multiple outbreaks of dengue, Zika, and chikungunya with substantial health and economic impacts. Vector control remains the most effective method for reducing disease risk, but comprehensive data on local mosquito vector composition, distribution, and abundance are needed to guide new, effective control efforts. From 2022 to 2024, we conducted a longitudinal baseline assessment of mosquito abundance and species composition on Ebeye and nearby islets in Kwajalein Atoll, RMI, using BG-Sentinel traps and ovitraps. Aedes aegypti was the most prevalent species, accounting for 58% of all adult females collected across study locations, with higher relative abundances on Ebeye than on northern islets (4.7 vs. 2.3 per trap/night). Aedes albopictus was more abundant on northern islets (0.7 vs. 3.2 per trap/night), and Culex quinquefasciatus showed similar abundances (1.2 vs. 1.7 per trap/night). Rainfall and anthropogenic factors, including water storage practices and housing density, influenced mosquito abundance. These findings provide multi-seasonal baseline data to support targeted vector control strategies in RMI.

Figures