Association of Deforestation With Severe Fever With Thrombocytopenia Syndrome

Deforestation increases the risk of severe fever with thrombocytopenia syndrome (SFTS). Shifted ecosystems, or substituted land use, resulting from deforestation alters relationships between vector, reservoir, and host. An integrated approach that accounts for deforestation is required for SFTS surveillance. Background Severe fever with thrombocytopenia syndrome (SFTS) virus was first isolated in China in 2009 and has since spread to several Asian countries. SFTS is closely related to environmental factors that accelerate vector growth. We evaluated the associations of SFTS and deforestation with environmental variables. Methods For this observational study, we generated multiple Poisson models using national SFTS outbreak data (2013-2018) and official environmental data for Korea. We included established risk factors as variables. Deforestation was used as the main variable. All variables were analyzed according to their spatial characteristics using the R-INLA package. Results SFTS cases increased over time and peaked in 2017, at 272, followed by a decrease in 2018. Disease mapping showed a high incidence of SFTS nationwide, with particular risks in Gangwon and Gyeonggi Provinces in the north, and Jeju in the south of South Korea. Deforestation was significantly associated with a higher risk of SFTS in the final model (relative risk, 1.751 [95% confidence interval, 1.125-2.743]). Conclusions SFTS outbreaks are associated with deforestation. Therefore, deforestation in Gyeonggi, Gangwon, and Jeju provinces of South Korea needs to be considered in vector-control strategies and active surveillance of SFTS occurrence.