BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a newly 
identified viral zoonosis caused by a phlebovirus. Most reported SFTS cases are 
farmers living in rural areas. The seroprevalence of SFTS virus in farmers has 
not been investigated. The current knowledge of SFTS virus seroprevalence in 
animals, especially in wild animals, is still poor.
OBJECTIVES: To investigate SFTS virus seroprevalence among farmers and a variety 
of animal species.
STUDY DESIGN: SFTS virus antibodies in sera were determined using a 
double-antigen sandwich ELISA. Serum samples were collected from 2547 farmers 
and 2741 animals in 6 SFTS-endemic counties from March 2012 to February 2013 in 
Jiangsu province. The farmer participants aged from 15 to 90 years. All of them 
were interviewed using a structured questionnaire. The animals sampled included 
6 domesticated animal species and 2 wild animal species.
RESULTS: SFTSV antibodies were found in a total of 33 farmers (1.30%) and was 
more prevalent in males than in females (respectively 1.87% and 0.71%, P<0.01). 
The mean age of seropositive farmers was 56.5 years and seroprevalence increased 
gradually with age. Seroprevalence in animal species were: goats (66.8%), cattle 
(28.2%), dogs (7.4%), pigs (4.7%), chickens (1.2%), geese (1.7%), rodents (4.4%) 
and hedgehogs (2.7%). Multiple variable logistic regression analysis showed that 
grazing, grass mowing, raising cattle, age, farm work time and tick bites were 
risk factors for SFTS virus infection among farmers.
CONCLUSIONS: SFTSV readily infects humans with farming-related exposures as well 
as numerous domestic and wild animals. Serological results further suggest that 
the virus circulates widely in Jiangsu province.