Molecular Epidemiology and Genetic Diversity of Zika Virus from Field-Caught Mosquitoes in Various Regions of Thailand.

Atchara Phumee,Akanitt Jittmittraphap,Rome Buathong,Supaporn Wacharapluesadee,Rungfar Boonserm,Proawpilart Intayot,Yutthana Joyjinda,Padet Siriyasatien,Nucharat Aungsananta

doi:10.3390/pathogens8010030

Abstract

Zika virus (ZIKV) infection is an emerging and re-emerging arbovirus disease that is transmitted to humans through the bite of infected mosquitoes. ZIKV infections were first described in Thailand in 1954 from the sera of indigenous residents and several travelers returning from Thailand in 2014. However, reported cases in Thailand have been increasing since 2015 and 2016, and epidemiological information about the vectors of ZIKV is unclear. We investigated the molecular epidemiology and genetic diversity of ZIKV from mosquitoes collected from different geographic regions experiencing ZIKV outbreaks in Thailand. Polymerase chain reaction was used to amplify the non-structural protein (NS5) gene of ZIKV, which was then sequenced. A total of 1026 mosquito samples (626 females, 367 males, and 33 larvae) were collected from active ZIKV patients’ houses. ZIKV was detected in 79 samples (7.7%), including Aedes aegypti (2.24% female, 1.27% male, and 0.19% larvae), Culex quinquefasciatus (1.85% female, 1.66% male, and 0.29% larvae), and Armigeres subalbatus (0.1% female and 0.1% male), whereas no ZIKV was detected in Aedes albopictus. Phylogenetic analysis of the 79 positive samples were classified into two clades: Those closely related to a previous report in Thailand, and those related to ZIKV found in the Americas. This is the first report of the detection of ZIKV in Ae. aegypti, Cx. quinquefasciatus, and Ar. subalbatus mosquitoes, and genetic variations of ZIKV in the mosquitoes collected from several geographic regions of Thailand were examined. Detection of ZIKV in male and larval mosquitoes suggests that vertical transmission of ZIKV occurred in these mosquito species. This study provides a more in-depth understanding of the patterns and epidemiologic data of ZIKV in Thailand; the data could be used for future development of more effective prevention and control strategies of ZIKV in Thailand.

Highlights

The Zika virus (ZIKV) is a mosquito-borne flavivirus, closely related to dengue, Japanese encephalitis, West Nile, and yellow fever viruses [1]
In 1966, ZIKV was first isolated in Asia from Ae. aegypti mosquitoes collected in Malaysia [6]
We investigated the potential vectors, molecular epidemiology, and genetic diversity of ZIKV in mosquitoes from several affected regions in Thailand by using Hemi-nested real-time polymerase chain reaction of the non-structural protein (NS5) gene

Summary

Introduction

The Zika virus (ZIKV) is a mosquito-borne flavivirus, closely related to dengue, Japanese encephalitis, West Nile, and yellow fever viruses [1]. ZIKV was first isolated from an Aedes africanus mosquito collected at the same site [4] and documented in humans in 1952 from Uganda and the United Republic of Tanzania [5]. In 1966, ZIKV was first isolated in Asia from Ae. aegypti mosquitoes collected in Malaysia [6]. There are some reports of ZIKV cases among Canadian [8], German [9], and Japanese [10] travelers returning from Thailand in 2014. The MoPH reported the first two indigenous cases of ZIKV-related microcephaly in Asia since September 2016 [13]. Human ZIKV infection cases had been reported, data are lacking on ZIKV in mosquito vectors in Thailand. Many studies reported that Aedes mosquitoes such as Ae. africanus, Ae. aegypti, Ae. apicocoargenteus, Ae. furcifer, Ae. vitattus, and Ae

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