Molecular detection of Indian Ocean Lineage Chikungunya virus RNA in field collected Culex quinquefasciatus Say from Bangkok, Thailand but no evidence of virus replication

Atchara Phumee; Proawpilart Intayot; Sriwatapron Sor-Suwan; Akanitt Jittmittraphap; Padet Siriyasatien

doi:10.1371/journal.pone.0246026

Molecular detection of Indian Ocean Lineage Chikungunya virus RNA in field collected Culex quinquefasciatus Say from Bangkok, Thailand but no evidence of virus replication

PLoS One. 2021 Jan 28;16(1):e0246026. doi: 10.1371/journal.pone.0246026. eCollection 2021.

Authors

Atchara Phumee¹, Proawpilart Intayot², Sriwatapron Sor-Suwan³, Akanitt Jittmittraphap⁴, Padet Siriyasatien³

Affiliations

¹ Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thamarat, Thailand.
² Medical Science Program, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
³ Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
⁴ Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.

Abstract

Following an outbreak of chikungunya virus (CHIKV) infections in Thailand in 2019, numerous cases of CHIKV infection have been diagnosed in Bangkok, the capital of the country. In our previous investigation of the vectors for disease transmission, we found natural infection of CHIKV in both male and female Aedes aegypti mosquitoes collected from the outbreak areas in Bangkok. Some reports mentioned the detection of CHIKV in Culex mosquitoes. In Thailand, the Culex quinquefasciatus Say mosquito is a common species found in urban and rural settings that coexists with Ae. aegypti. However, the role of Cx. quinquefasciatus mosquitoes in the spread of the Indian Ocean Lineage (IOL) of CHIKV in Thailand has never been investigated. In this study, Cx. quinquefasciatus were collected (16 males and 27 females) from an outbreak area in Bangkok. Eight of the 27 in field-caught female Cx. quinquefasciatus were positive for IOL CHIKV RNA, and 99-100% identity and full 100% coverage of sequences similar to CHIKV isolated from female Ae. aegypti in Bangkok, Thailand, whereas viral RNA was not detected in male samples using nested-RT-PCR. To determine whether CHIKV is able to replicate in Cx. quinquefasciatus, the laboratory strain of Cx. quinquefasciatus was allowed to feed on blood containing IOL CHIKV isolated from patient serum. The nested-RT-PCR, virus isolation, and immunofluorescence assay (IFA) were performed for CHIKV detection and replication. The results showed that CHIKV RNA was detected in Cx. quinquefasciatus until day 4 post infection. CHIKV did not produce any remarkable signs of infection, dissemination, or transmission in Cx. quinquefasciatus, and cytopathic effect (CPE) was not observed in C6/36 cells when infected with supernatant obtained from Cx. quinquefasciatus at days 7, 10, 14, and 21 post infection when compared to Ae. aegypti. The data from this study infer that CHIKV may be detected in Cx. quinquefasciatus but that the mosquito is not able to transmit CHIKV in Thailand.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Chikungunya Fever / transmission
Chikungunya Fever / virology*
Chikungunya virus / genetics
Chikungunya virus / isolation & purification*
Culex / virology*
Female
Male
Thailand
Virus Replication*

Grants and funding

This study was supported by the Second Century Fund (C2F), Chulalongkorn University, the new strategic research project (P2P), Walailak University, Thailand, National Research Council of Thailand (NRCT): (Grant No. NRCT5-RSA63001-03), Health Systems Research Institute (Grant No. 63-017), Rachadapisek Sompote Fund (RA/MF 21/63), the Thailand Research Fund and Chulalongkorn University, the Program Management Unit for Human Resources & Institutional Development, Research and Innovation - CU (Grant No. B16F630071), TSRI Fund (Grant No. CU_FRB640001_01_30_1), and NIH/NIAID/CREID/07-049-7012-52338. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.