The research study involves testing horses in the Republic of Korea for SFTSV, a tick-borne virus that causes severe fever with thrombocytopenia syndrome. The results showed that 12 out of 889 horses tested positive for the virus, and 51% had SFTSV-specific antibiodies, indicating a potential health risk for people closely associated with horses.

Study Details

• The researchers aimed to investigate the prevalence of SFTSV, a virus that causes a severe fever condition with low platelet count in humans, in horses in South Korea.
• A total of 889 horses were included in the study. Their samples were collected over a period from 2018 to 2020 from a slaughterhouse and equestrian centers across the country.
• The collected blood samples were used to examine the presence of SFTSV RNA and to check for antibodies specific to SFTSV.

Methodology

• The researchers extracted RNA from the serum samples of the horses and conducted a nested RT-PCR test to detect the presence of SFTSV.
• Sequencing data produced from positive samples were analyzed and a phylogenetic tree (a diagram showing evolutionary relationships) was constructed using a software tool known as Molecular Evolutionary Genetics Analysis Version 7.0.
• To look for antibodies specific to SFTSV, an ELISA test was administered, which could indicate exposure to the virus in the past.

Findings

• Of the tested horses, 1.3% (12 out of 889) were found to carry SFTSV RNA, signifying current or recent infection.
• Notably, 51% of the horses were found to carry antibodies against SFTSV, indicating that they had been exposed to the virus at some point.
• The SFTSV sequences found in the 12 positive samples were classified into two sub-genotypes, B-2 and B-3, each found in 6 samples.

Implications and Future Research

• The results of the study suggest an ongoing infection of SFTSV among horses in South Korea, which could pose a health risk to those who are in close contact with these horses (such as equestrian workers).
• Even though the study was carried out over a 3-year period, the sampling was not evenly conducted by season which is a limitation. The researchers recommend continuous surveillance of SFTSV in horses to better understand the situation.