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

Abstract

Background Studying 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. Results Different 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). Conclusions These 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.

A community based case-control study to determine the risk factors of dengue fever in Bangladesh

“…On the other hand, housewives were at a higher risk of infection (OR= 2.29) although the relation was nonsignificant. It indicates that house status and environment play a role in dengue transmission may be due to the presence of Aedes mosquito larvae and breeding sites in and around the houses of the study area found by an entomological survey (Rahman et al 2021). On the other hand, government employees and students were significantly associated with protection against dengue virus infection.…”

“…The copyright holder for this preprint this version posted August 26, 2021. ; https://doi.org/10.1101/2021.08.24.21262563 doi: medRxiv preprint et al 2015b). Single houses presented higher odds (2.49) for the infection of occupants which may be due to high densities of Aedes larvae recorded in single independent houses of the study area (Rahman et al 2021). Single houses are small building or semi paka structure inhabitants of one or two families.…”

“…Hence, urbanization has been considered as one of the drivers of dengue fever dynamics. However, in recent times dengue is not only transmitting in urban setting rather spread in rural villages also by secondary vector Aedes albopictus which has found available in the study area (Rahman et al 2021).…”

“…The copyright holder for this preprint this version posted August 26, 2021. ; https://doi.org/10.1101/2021.08.24.21262563 doi: medRxiv preprint in rural villages also by secondary vector Aedes albopictus which has found available in the study area (Rahman et al 2021).…”

“…Since Bangladesh is a densely populated developing country, rapid urbanization, unregulated infrastructure development, poor sewerage system in cities, and monsoon rains provided a suitable condition for the dengue virus to replicate at a higher rate which ultimately increases the risk of dengue transmission among the people (Mahmood and Mahmood 2011). A local survey found that households of Chattogram city were infested with Aedes mosquito larvae (Rahman et al 2021).…”