Abstract
This study examined household risk factors and prevalence, abundance, and distribution of immature Aedes aegypti and Aedes albopictus, and their association with socioeconomic and ecological factors at urban zonal and household levels in the city of Dhaka, Bangladesh. During the 2011 monsoon, 826 households in 12 randomly selected administrative wards were surveyed for vector mosquitoes. Results revealed that the abundance and distribution of immature Ae. aegypti and Ae. albopictus, and pupae-per-person indices did not vary significantly among the zones with varied socioeconomic status. Of 35 different types of identified wet containers, 30 were infested, and among the 23 pupae-positive container types, nine were defined as the “most productive” for pupae including: disposable plastic containers (12.2% of 550), sealable plastic barrels (12.0%), tires (10.4%), abandoned plastic buckets (9.6%), flower tub and trays (8.5%), refrigerator trays (6.5%), plastic bottles (6.4%), clay pots (4.9%), and water tanks (1.6%). When the function of the containers was assessed, ornamental, discarded, and household repairing and reconstruction-related container categories were found significantly associated with the number of pupae in the households. The purpose of storing water and income variables were significant predictors of possession of containers that were infested by vector mosquitoes.
Highlights
Worldwide, more than 50 million dengue virus (DENV) infections occur each year, including 500,000 hospitalizations for dengue hemorrhagic fever (DHF), with the case fatality rate exceeding 5% in some areas.[1,2] others estimate the size of annual dengue infection globally to be much larger—390 million, of which 90 million manifest symptoms of varying levels of clinical or subclinical severity.[3]
Because no antiviral drugs and vaccines are commercially available for DENV, vector control is the primary means to reduce dengue transmission and there are relatively few examples in the literature where dengue outbreaks have been successfully controlled through implementation of vector control measures
The results of our study provide evidence that Ae. aegypti productivity is significantly influenced by household socioeconomic factors, through container ownership and ecological factors in the city of Dhaka, Bangladesh, and they are consistent with the findings of some recent studies.[11,23,24,25]
Summary
More than 50 million dengue virus (DENV) infections occur each year, including 500,000 hospitalizations for dengue hemorrhagic fever (DHF), with the case fatality rate exceeding 5% in some areas.[1,2] others estimate the size of annual dengue infection globally to be much larger—390 million, of which 90 million manifest symptoms of varying levels of clinical or subclinical severity.[3]. In a pilot project in Singapore in the late 1960s, the development of a vector control system, based on entomological surveillance and larval source reduction, resulted in the reduction of the Ae. aegypti population from 16 to 2% in a 3-month period, as measured by the premises index.[4,5] Guzman and Kouri[6] observed successful vector eradication campaigns starting in the mid-1940s through larval control in domestic water storage containers and use of insecticides,[7] and most countries in the Central and South American regions were free of the vector. These regions were reinfested by Ae. aegypti during the 1960s and 1970s.6
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