Isolation and Identification of Arboviruses from Mosquitoes in Yuxi Region of Yunnan, China

Background: Arboviruses, transmitted to humans and animals by blood-feeding arthropods, pose significant public health risks. This study investigates the types, distribution, and epidemiology of arboviruses in the central Yuxi region of Yunnan Province, providing crucial data for the prevention and control of mosquito-borne diseases. Methods: In 2015, mosquitoes were collected from Tonghai County, Huaning County, Jiangchuan District, and Chengjiang County in Yuxi using light traps. The mosquitoes were homogenized, and virus isolation was performed by inoculating the homogenates onto BHK-21 (baby hamster kidney) and C6/36 (Aedes albopictus) cell lines. Reverse Transcription Polymerase Chain Reaction (RT-PCR) amplification was performed with universal and virus-specific primers, followed by sequencing of positive products using bioinformatics tools (DNAstar, MEGA X). Results: A total of 13,050 mosquitoes from four counties were collected, with 261 pools processed for virus detection. The mosquitoes belonged to three genera: Culex Anopheles and Aedes, with Culex tritaeniorhynchus as the predominant species. Cytopathic effects were observed in 95 pools. Nine viruses were identified: Japanese Encephalitis Virus (JEV), Bannavirus, Getah Virus, Tibet Orbivirus (TIBOV), Nam Dinh Virus, Akabane Virus (AKAV), Ngewotan Virus (NWTV), Quang Binh Virus (QBV), and Culex pipiens pallens densovirus. The distribution of viruses varied: six viruses with 35 isolates in Tonghai County; six viruses with 88 isolates in Huaning County; two viruses with five isolates in Chengjiang County; and no viruses were found in Jiangchuan District. TIBOV and NWTV were present in all three counties, while JEV, AKAV, and QBV were found only in Tonghai County. Conclusion: Nine arboviruses were isolated across four counties in Yuxi, with varying distributions. This highlights the epidemiological diversity of mosquito-borne viruses in the region, emphasizing the need for targeted control measures.