Availability and Breeding Preferences of Aedes Mosquitoes in Fifteen High Altitude Localities, Maekel Region, Eritrea: A Cross-sectional Study

Abstract

Background: Even-though dengue fever suspicion started to surface in the high altitude localities of Zoba Maekel, presence of the vector has not been studied. Therefore, the study aimed to identify the availability of Aedes mosquitoes, their breeding preferences, and level of infestation in fifteen localities of this region.Methods: Inspection of all water holding containers, in 740 systematically selected households of fifteen localities, was done identifying immature stages of Aedes mosquitoes. All immatures were then, classified, reared and identified using taxonomic keys. Breeding preferences ratio and infestation indices were calculated.Results: In this study Aedes Aegypti mosquito was found in four localities, whereas mosquito of other Aedes specie was identified in twelve localities. Out of all the households inspected 51 were positive for Aedes immature. All indoor containers studied were free of Aedes infestation, whilst 53 of 874 outdoor containers were infested by Aedes larvae and pupae. In this study, discarded tyres were found to have the highest breeding preference ratio (2.11) and pupal productivity (40%). Plastic barrels had the highest positivity (42%) and were the second most productive type of container (28%). The Household, Container and Breteau Indices of more than half of the localities were higher than the high transmission risk thresholds.Conclusion: The study indicated possibilities of local dengue fever transmission in the studied areas. Hence, in depth confirmative studies should be considered and strategic preventive actions should be commenced in regard to the most preferred sites such as discarded tyres.