[Survey on mosquito species diversity and pathogen spectrum of arbovirus in tropical regions of China].

Objective

To investigate the species and distribution of mosquitoes and pathogen spectrum of arbovirus in tropical regions of China.

Methods

From April 2023 to December 2024, mosquitoes were collected at various survey sites in the tropical regions of Guangdong Province, Guangxi Zhuang Autonomous Region, Yunnan Province, and Hainan Province. Classify and identify collected mosquitoes using morphological and molecular biological methods (1-50 specimens per tube). Arboviruses in mosquito specimens were detected using Sanger first-generation sequencing and high-throughput second-generation sequencing. Using the PooledInfRate v4 plugin to estimate arboviruses prevalence rates in tropical survey areas.

Results

A total of 40 481 mosquitoes were collected from 70 township-level sampling sites across 22 cities (autonomous) prefectures in four provinces of China. These specimens were identified morphologically and molecularly as belonging to 5 genera and 31 species. The Culex tritaeniorhynchus, Anopheles sinensis, Aedes albopictus, Armigeres subalbatus, and Mansonia uniformis were the ecologically dominant species within the Culex, Anopheles, Aedes, Armigeres, and Mansonia genera, respectively, in the tropical survey areas. Culex tritaeniorhynchus was the dominant mosquito species, accounting for 69.08% (27 963/40 481). Anopheles sinensis ranked second (9.11%, 3 688/40 481), followed by Aedes albopictus (6.58%,2 662/40 481). This survey identified 10 pathogenic arboviruses and 43 insect-specific viruses, distributed across 16 families and the Negevirus taxon. The prevalence rates of Tembusu virus, Japanese encephalitis virus, Dengue virus, Nam Dinh virus, Cat Que virus, Batai virus, Umbre virus, Banana virus, Mangshi virus, and Getah virus among mosquito vectors in China's tropical regions of investigation were all relatively low. The maximum and minimum values of the maximum likelihood estimation (MLE) for prevalence rates of these pathogenic arboviruses in mosquito vectors from tropical survey areas were 4.78/10 000 (95%CI: 2.26/10 000-9.08/10 000) and 0.25/10 000 (95%CI: 0.01/10 000-1.19/10 000), respectively. The prevalence rate of Japanese encephalitis virus in Culex tritaeniorhynchus in tropical survey areas was 0.36/10 000 (MLE, 95%CI: 0.02/10 000-1.73/10 000). The prevalence rate of Batai virus in Aedes albopictus in tropical survey areas was 3.76/10 000 (MLE,95%CI: 0.22/10 000-18.20/10 000). 30.23% (13/43) of specific viruses exhibited high infection rates among mosquito vectors across all four surveyed provinces.

Conclusions

The tropical regions of Guangdong Province, Guangxi Zhuang Autonomous Region, Yunnan Province, and Hainan Province harbor a wide range of mosquito vectors, with Culex tritaeniorhynchus being the predominant species. This survey also revealed the circulation of multiple pathogenic arboviruses and insect-specific viruses in China's tropical regions.