Entomological survey for identification of Aedes larval breeding sites and their distribution in Chattogram, Bangladesh

Md Sahidur Rahman,Najmul Haider,Sumiya Tanjila,Nur Mohammad Sabbir,Md Omar Faruk,Sharmin Chowdhury

doi:10.1186/s43088-021-00122-x

Abstract

BackgroundStudying the characteristics of Aedes mosquito habitats is essential to control the mosquito population. The objective of this study was to identify the breeding sites of Aedes larvae and their distribution in Chattogram, Bangladesh. We conducted an entomological survey in 12 different sub-districts (Thana) under Chattogram City, during the late monsoon (August to November) 2019. The presence of different wet containers along with their characteristics and immature mosquitoes was recorded in field survey data form. Larvae and/or pupae were collected and brought to the laboratory for identification.ResultsDifferent indices like house index, container index, and the Breteau index were estimated. The multiple logistic regression analysis was applied to identify habitats that were more likely to be positive for Aedes larvae/pupae. A total of 704 wet containers of 37 different types from 216 properties were examined, where 52 (7.39%) were positive for Aedes larvae or pupae. Tire, plastic buckets, plastic drums, and coconut shells were the most prevalent container types. The plastic group possessed the highest container productivity (50%) whereas the vehicle and machinery group was found as most efficient (1.83) in terms of immature Aedes production. Among the total positive properties, 8% were infested with Aedes aegypti, 2% with Aedes albopictus, and 1% contained both species Ae. aegypti and A. albopictus. The overall house index was 17.35%, the container index was 7%, and the Breteau index was 24.49. Containers in multistoried houses had significantly lower positivity compared to independent houses. Binary logistic regression represented that containers having shade were 6.7 times more likely to be positive than the containers without shade (p< 0.01).ConclusionsThese findings might assist the authorities to identify the properties, containers, and geographical areas with different degrees of risk for mosquito control interventions to prevent dengue and other Aedes-borne disease transmissions.

Highlights

Studying the characteristics of Aedes mosquito habitats is essential to control the mosquito population
Vector control remains the center of dengue prevention options, which can be done by limiting the transmission potential by reducing the emergence of adult mosquitoes
2 Methods This entomological survey was conducted in late monsoon in 2019 between August and November, when dengue incidence was high in the study area and throughout Bangladesh [6]

Summary

Introduction

Studying the characteristics of Aedes mosquito habitats is essential to control the mosquito population. Aedes albopictus belongs to the same subgenus (Stegomyia) considered as a secondary vector of DENV They are primarily found in rural areas and peridomestic sites of urban areas like parks and green corridors interspersing housing estates. Both of these species were first recorded in Bangladesh in 1952 [2]. Vector control remains the center of dengue prevention options, which can be done by limiting the transmission potential by reducing the emergence of adult mosquitoes This could be achieved by targeting the aquatic habitats of the immature stages of Ae. aegypti through source reduction or biological and/or biocidal treatment [8, 9]. The productivity of a container type depends on a range of factors, such as size and shape, the purpose of use, their locations, method of filling (passively/actively), the material of the container (plastic, metal, cement/clay, etc.), temperature, availability of food, and competition among co-species [10, 11]

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