An entomological analysis on the prevalence of dengue vectors in urban areas of Ernakulam district, Kerala, India

Abstract

Dengue is one of the major mosquito-borne diseases in Kerala, posing a threat to human health. Stegomyia aegypti and Stegomyia albopicta are serving as the primary and secondary vector of the dengue virus, respectively in Kerala. The present study was conducted to know the diversity and breeding sites along with the level of infestation of dengue vectors in the urban areas of the Ernakulam district of the Kerala state. The present study was carried out for a period of 11 months, i.e. from October 2017 to August 2018. A cross sectional survey entomological survey was carried out in the peridomestic areas for the breeding of mosquito immatures in the water holding containers in the study area. A total of 7018 water holding containers form 3025 houses were surveyed during the study period of which 801 containers from 508 houses were harboring mosquito immatures either larvae or pupae. Stegomyia albopicta was the dominant container breeding mosquito in the area and presence of Stegomyia aegypti was also identified in the area. Co-infestation of mosquito species in breeding habitats was reported in the study. The most frequently encountered breeding sites were plastic containers, earthen, glass containers, tyres and cement tanks etc. Twelve species were recorded in the present study including the major dengue vector, Stegomyia aegypti and the urban malaria vector, Anopheles stephensi. Stegomyia indices were high during the month of June and lowest in the month of February. This baseline data on the vector density can help the authorities in planning and evaluation of vector control activities specific to the local ecology of the vector.