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

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.

Travel Surveillance and Genomics Uncover a Hidden Zika Outbreak during the Waning Epidemic

“…A single report about a Zika outbreak in Cuba made the news in 2017 ( Reuters, 2017 ), but critically, cases were not reported to PAHO ( PAHO, 2017c ) or other public health agencies and thus went undetected by the international community. With Zika outbreaks still arising in new locations, including Angola, India, Cabo Verde, Vietnam, and Thailand ( Hill et al., 2019 , Lourenço et al., 2018 , Meltzer et al., 2016 , Phumee et al., 2019 , Ruchusatsawat et al., 2019 , Yadav et al., 2019 ), it is important to identify and report lingering outbreaks to better prepare for potential future spread ( Bogoch et al., 2016 , Kraemer et al., 2017 ).…”

“…By mid-2017, reports from the Pan American Health Organization (PAHO) ( PAHO, 2017a , PAHO, 2017b ) revealed Zika virus activity throughout the Americas was waning, prompting predictions for the end of the epidemic (e.g., O’Reilly et al., 2018 ) and the removal of the World Health Organization’s (WHO’s) “Public Health Emergency of International Concern” status ( WHO, 2016a , WHO, 2016b ). More recently, however, new Zika outbreaks have been described across the world ( CDC, 2018 ), including from Angola, India, Cabo Verde, Vietnam, and Thailand, with some of these resulting from Zika virus introductions from the epidemic in the Americas (e.g., Hill et al., 2019 , Lourenço et al., 2018 , Meltzer et al., 2016 , Phumee et al., 2019 , Ruchusatsawat et al., 2019 , Yadav et al., 2019 ). These observations would suggest that significant transmission of Zika virus in the Americas could still be ongoing, despite case reporting having come close to zero.…”

Zika and dengue viruses infecting wild-caught mosquitoes in an environmental protection area in Brazil

“…quinquefasciatus (DENV-4) [57]; species infected with ZIKV include Ae. aegypti [59, 60], Cx. quinquefasciatus and Armigeres subalbatus [60].…”

“…aegypti [59, 60], Cx. quinquefasciatus and Armigeres subalbatus [60]. Aedes aegypti , considered the main vector of DENV and ZIKV in Brazil and other parts of the world [16,58], was not found in the Capivari-Monos EPA, probably because this species is an urban mosquito and the collection sites were in wild environments.…”

The Taxonomic Signal of the Internal Mosquito Wing Cells.

“…In addition to transmitting the chikungunya virus, they are able to spread all of the four dengue serotypes (DENV1-4). Aedes aegypti is also a competent vector of Zika virus [11,12,13]. Ae.…”