Abstract
Chikungunya virus (CHIKV) is a mosquito-borne virus belonging to the genus Alphavirus. The virus is transmitted to humans by the bite of infected female Aedes mosquitoes, primarily Aedes aegypti. CHIKV infection is spreading worldwide, and it periodically sparks new outbreaks. There are no specific drugs or effective vaccines against CHIKV. The interruption of pathogen transmission by mosquito control provides the only effective approach to the control of CHIKV infection. Many studies have shown that CHIKV can be transmitted among the Ae. aegypti through vertical transmission. The previous chikungunya fever outbreaks in Thailand during 2008–2009 were caused by CHIKV, the East/Central/South African (ECSA) genotype. Recently, there have been 3794 chikungunya cases in 27 provinces reported by the Bureau of Epidemiology of Health Ministry, Thailand during 1 January–16 June 2019; however, the cause of the re-emergence of CHIKV outbreaks is uncertain. Therefore, the aims of this study were to detect and analyze the genetic diversity of CHIKV infection in field-caught mosquitoes. Both female and male Ae. aegypti were collected from endemic areas of Thailand, and CHIKV detection was done by using E1-nested RT-PCR and sequencing analysis. A total of 1646 Ae. aegypti samples (900 females and 746 males) were tested. CHIKV was detected in 54 (3.28%) and 14 samples (0.85%) in female and male mosquitoes, respectively. Seventeen samples of female Ae. aegypti collected from the Ubon Ratchathani, Chiang Rai, Chiang Mai, Nakhon Sawan, and Songkhla provinces found mutation at E1: A226V. Interestingly, E1: K211E mutation was observed in 50 samples collected from Nong Khai, Bangkok, Prachuap Khiri Khan, and Krabi. In addition, the phylogenetic tree indicated that CHIKV in Ae. aegypti samples were from the Indian Ocean Clade and East/South African Clade. Both clades belong to the ECSA genotype. The information obtained from this study could be used for prediction, epidemiological study, prevention, and effective vector control of CHIKV. For instance, a novel CHIKV strain found in new areas has the potential to lead to a new outbreak. Health authorities could plan and apply control strategies more effectively given the tools provided by this research.
Highlights
Chikungunya virus (CHIKV) is a species of the genus Alphavirus belonging to the familyTogaviridae, which has a genome consisting of a linear, positive-sense, single-stranded RNA molecule of approximately 11.8 kb
Our results show that 17 samples found the E1: A226V mutation from female of Ae. aegypti; we found that the E1: K211E mutation was observed in 50 samples from both female and male Ae. aegypti collected from Nong Khai, Bangkok, Prachuap Khiri Khan, and Krabi
We highlight the natural infection of CHIKV RNA in female and male Ae. aegypti from the chikungunya fever endemic area of Thailand
Summary
Chikungunya virus (CHIKV) is a species of the genus Alphavirus belonging to the familyTogaviridae, which has a genome consisting of a linear, positive-sense, single-stranded RNA molecule of approximately 11.8 kb. The genome of CHIKV is considered to be 50 cap-nsP1-nsP2-nsP3-nsP4-(junction region)-C-E3-E2-6K-E1-poly (A) 30 [1,2]. CHIKV consists of three genotypes: East/Central/South African (ECSA), West African (WA), and Asian. Vazeille et al (2007) revealed that the ECSA genotype carrying a new variant of mutation at alanine-to-valine (A226V) in the E1 protein has spread in areas where. This mutation has shown to be increasing the fitness of the virus for Ae. albopictus mosquitoes as well as its infectivity [3]. CHIKV infection is one of the emerging and re-emerging mosquito-borne viral diseases transmitted by Aedes mosquitoes such as Ae. aegypti and Ae. albopictus, the Asian tiger mosquito associated with several recent large-scale epidemics [4,5].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
