Distribution of yellow fever vectors in a disease-free area of Northeast Brazil

Background:  Owing to the recent spread of the yellow fever virus in Brazil and imminent risk of its establishment in previously disease-free areas in the northeast of the country, epidemiological surveillance actions are necessary, including knowledge of non-human primate populations and the vectors that inhabit risk areas. The objective of this study was to evaluate the movement of sylvatic and urban yellow fever vectors between an Atlantic Forest fragment and its surrounding areas.

Methods:  The study site was the Mata do Junco Wildlife Refuge Conservation Unit (CU) in Capela, Sergipe, Brazil. Immatures were collected using ovitraps in the forested area and in peridomestic environments surrounding the CU.

Results:  Fourteen species were recorded, six of which were epidemiologically relevant. The main vectors of yellow fever in Brazil were present in the CU. Aedes albopictus (Skuse, 1894) was the most abundant species and was present in all studied environments. Aedes aegypti (Linnaeus, 1762) was not collected from forested areas. Among the native species, Haemagogus leucocelaenus (Dyar & Shannon, 1924) and Haemagogus janthinomys (Dyar, 1921) were collected only in the forested area of the CU, whereas Haemagogus spegazzinii (Brètes, 1921) was collected both in the forest and in the area around the CU.

Conclusion:  Exotic species circulate between wild and urban areas for feeding and oviposition, but circulation to the urban area is limited among native species.

Keywords:
Arboviruses; Vector ecology; Entomological surveillance; Epizootics