Dengue Virus Infecting Mosquito Vectors and Non-recognized Vectors in Zoological Parks: a Call for Vector Borne Diseases Surveillance

Abstract

Purpose: To investigate the prevalence of zoonotic mosquito-borne viruses in mosquitoes, and to determine the eco-biology of mosquito populations in the zoos of Thailand. Thus, to ascertain the risks of zoonotic mosquito-borne virus infections in animals and humans, and for future research on prevention and control of these viruses to minimize zoonotic transmission and prevent emergence or re-emergence of local and exotic mosquito-borne viral diseases. Methods & Materials: Mosquitoes were collected in three zoological parks in Thailand. Collection sites, six in CM, eight in KK and five in BK, were selected targeting zones hosting avian, non-human primates and ungulates. A cross-sectional adult mosquito collections were carried out during two night sessions (18:00 – 07:00 hour) and two daytime sessions (07:00 – 19:00 hour) by using BG (BIOGENT)-Sentinel in combination with the BG-Lure, during the night and daytime sessions, respectively; and CDC type miniature Light Trap baited with dry ice as a source of C02, during night time sessions. Two-step RT-PCR was performed on the viral nucleic extracts using flavivirus universal primer pairs targeting the NS5 region, then PCR amplicons were purified and the nucleotide sequences of the purified PCR amplicons were determined by automated DNA sequencing using Dye Terminator sequencing technology at 1st BASE. Results: A total of 767 mosquitoes 6 genera within 4 species were collected and identified from 3 sites during the early rainy season of May 2018. Over the three sites, 6 genera of Culex, Aedes, Anopheles, Armigeres, Toxorhychites and Mansonia were recorded. Viral RNA of Dengue virus serotype 2 where identified in Aedes aegypti and Ae. albopictus, and in Mansonia sp. and Armigeres sp.; recognized mosquito vectors and non-recognized vectors respectively. Conclusion: The findings of the study reveal the need of the establishment of a arbovirus surveillance and monitoring program in the zoological parks for the appropriated control of the mosquitoes thriving in the parks and consequently reduce the risk for the emergence of zoonotic mosquito-borne virus infection in animals and humans.