Urban Ecology of Arboviral Mosquito Vectors Along the Kenyan Coast.

Martin Rono,Joseph Mwangangi,Simon Muriu,Charles M Mbogo,Donwilliams Omuoyo,George Warimwe,Moses Ngari,Boniface Karia,Doris Nyamwaya,Jonathan Karisa,Athanase Badolo

doi:10.1093/jme/tjaa136

Martin Rono, Joseph Mwangangi + Show 9 more

Open Access

https://doi.org/10.1093/jme/tjaa136

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Abstract

The purpose of this study was to determine the ecology of the common arboviral mosquito vectors in Mombasa, Kilifi and Malindi urban areas of coastal Kenya. Mosquito larvae were collected using standard dippers and pipettes. Egg survivorship in dry soil was evaluated by collecting soil samples from dry potential larval developmental sites, re-hydrating them for hatching and rearing of the eventual larvae to adults. Adult mosquitoes were collected with CDC light traps and BG-Sentinel traps. All blood-fed females were tested for bloodmeal origin. Mosquitoes were screened for arboviruses using RT-qPCR. Overall, the predominant species were Culex quinquefasciatus (Say) 72.4% (n = 2,364) and Aedes aegypti (L.), 25.7%, (n = 838). A total of 415 larval developmental sites were identified indoors (n = 317) and outdoors (n = 98). The most productive larval developmental sites, both indoors and outdoors, were assorted small containers, water tanks, drainages, drums, and jerricans. Overall, 62% (n = 18) of the soil samples collected were positive for larvae which were used as a proxy to measure the presence of eggs. The mosquitoes fed on humans (29.8%) and chickens (3.7%). Of 259 mosquitoes tested for viral infection, 11.6% were positive for Flavivirus only. The most productive larval developmental sites for arboviral vectors indoors were small containers, water tanks, jerricans, and drums whereas small containers, water tanks, drainage channels, buckets, tires, and water troughs were the productive larval developmental sites outdoors.

Highlights

Arboviruses are arthropod borne viruses transmitted by an enormous number of haematophagous arthropod species, including but not limited to ticks, mosquitoes and sand flies [1]
All larvae collected from indoor containers resulted in the emergence of only Aedes aegypti mosquitoes and this was consistent with other studies [10,76]
This could be attributed to the period of collection as we were interested to establish the dry ecology of mosquitoes

Summary

Introduction

Arboviruses are arthropod borne viruses transmitted by an enormous number of haematophagous arthropod species, including but not limited to ticks, mosquitoes and sand flies [1]. The emergence and re-emergence of arboviruses have significantly impacted on human and animal health as it results in global insecurity to all populations [35]. They have been attributed to high level of morbidity and mortality in sub-Saharan Africa and other tropical and subtropical environments [8]. The emergence and re-emergence of arboviral infections Chikungunya, dengue hemorrhagic fever, rift valley fever, and yellow fever in humans around the world threatens global health and security. Egg survivorship in dry soil was evaluated by collecting of soil samples from dry potential breeding habitats, watering them for hatching and rearing of the eventual larvae to adults. Of 259 mosquitoes tested for viral infection, 11.6% were positive for flavivirus only

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