Epidemiological investigation and etiological analysis on a cluster of severe fever with thrombocytopenia syndrome in a family

  Objective   To analyze the epidemiological characteristics of a cluster of severe fever with thrombocytopenia syndrome (SFTS) in a family, and provide the basic support for the disease prevention, control and surveillance.

  Methods   The epidemiological survey of 2 suspected fever cases were conducted, the healthy people and host animals in the nearby environment were monitored with serologic and etiologic methods. ELISA and real-time PCR were applied to detect the blood samples from the cases or animals and ticks samples. The nucleic acid positive samples were used for the sequencing of S, M and L genes of SFTS virus. The phylogenetic tree was constructed to analyze the association between the cases and the ticks

  Results   Two cases were SFTS virus IgM and total antibody positive, and one case was positive for nucleic acid of SFTS virus. Three of 45 healthy human serum samples were positive for SFTS virus antibody. In the host animals, 6 dogs (including cases’ domesticated dog) and four sheep were total antibody positive, while four pigs were negative. In 10 tick samples, SFTS virus was detected in 1 tick sample from the domesticated dog of the cases. Sequencing analysis showed that the S, M and L gene nucleotide homology of the cases and the tick was 99.9%–100.0%.

  Conclusion   The cluster of this SFTS in a family was highly associated with the domesticated dog and parasitic ticks on the dog.