Spatiotemporal dynamics of dengue: a town level study in Guangdong, China.

BACKGROUND

Dengue has been prevalent in Guangdong Province, China, for more than forty years and has shown an increasing trend over the past decade.

METHOD: A fine-scale analysis of dengue clusters was conducted. The relationship between virus evolution time and spatial distance was analyzed, and a genetic algorithm was used to quantify the effects of environmental, social, and economic factors on the transmission of dengue.

RESULTS

A retrospective study analyzed 172 confirmed dengue cases (April 2019 to April 2020) at the Seventh Affiliated Hospital of Southern Medical University. Whole-genome sequencing revealed a unique transmission origin in Lishui town, Guangdong Province (99.64% to 100% homology). Regardless of the duration of the outbreak (1, 3, or 6 months), the probability that cases within 5 km belonged to the same transmission chain decreased with distance, with a 60-70% probability observed within 200 m. Population density and income were more influential factors than vegetation and precipitation in terms of virus transmission.

CONCLUSION

The geographical distance among cases and the population density are crucial for determining dengue transmission during fine-scale outbreaks, highlighting important implications for control and surveillance and informing precise prevention strategies for dengue and other vector-borne viruses in China and tropical regions globally as well.

CLINICAL TRIAL NUMBER: Not applicable.