Sick Dog Linked to Family Cluster of Severe Fever with Thrombocytopenia Syndrome in China

Three members of a family in Southeast China fell ill with severe fever with thrombocytopenia syndrome (SFTS), a tick-borne viral disease with a substantial case-fatality rate, and all three had one thing in common: close care of a sick golden retriever before their symptoms began. The other two household members, who had no such canine exposure, remained serologically and clinically uninfected. The finding, reported by Jiangping Ren and colleagues, suggests a plausible canine-to-human transmission event within a family cluster.

The index case was a 57-year-old man. His son developed SFTS-compatible symptoms two days after his onset, and his wife followed three days after. All three cases were laboratory-confirmed for SFTS, yet each denied a tick-biting history before illness onset. Retrospective accounts placed all three in close contact with the ailing dog prior to their own symptoms.

Subsequent testing confirmed SFTS virus (SFTSV) infection in the golden retriever itself, and SFTSV was also detected in a tick collected from the dog. Because no tick bites were reported by the human cases, the chain of exposure points toward the animal rather than an arthropod vector, although the study stops short of proving direct transmission.

Longitudinal viral screening of serial canine samples revealed persistent SFTSV shedding long after the dog’s symptom onset. Viral positivity was sustained for 23 days in nasal swabs and urethral swabs, 27 days in serum samples, and at least 30 days in rectal swabs. Such prolonged shedding means an infected dog can remain a potential source of virus for weeks, well beyond the acute phase of its own illness.

Genomic analysis strengthened the epidemiological link. SFTSV sequences recovered from the index case and the infected dog were near-identical, with identities of 99.94% for the small segment, 100% for the medium segment, and 99.98% for the large segment. This degree of sequence identity is consistent with a shared viral strain circulating between the animal and the human cases in the same household.

The study’s authors state that their findings reveal prolonged SFTSV shedding in infected canines, suggest a plausible risk of canine-to-human SFTSV transmission, and highlight the potential role of dogs in the spread and evolution of the virus.

The evidence remains observational. The genomic identities are near-identical rather than exact across all segments, and the study describes a single family cluster rather than a systematic survey of canine carriage. Nevertheless, the combination of epidemiological exposure, laboratory confirmation in both dog and humans, and matching viral sequences marks this as a notable signal that domestic dogs may participate in the transmission cycle of a serious tick-borne human pathogen.

Subject of Research: A family cluster of severe fever with thrombocytopenia syndrome linked to persistent SFTSV carriage in a dog

Article Title: Persistent viral carriage of severe fever with thrombocytopenia syndrome virus in canine: A potential canine-to-human transmission event in a family cluster

Article References: Ren, J., Gu, S., Liu, Y., Yang, Y., Shi, X., Luo, X., Li, J., Zhu, L., Li, S., Yao, H., Tian, J., & Sun, J. (2026). Persistent viral carriage of severe fever with thrombocytopenia syndrome virus in canine: A potential canine-to-human transmission event in a family cluster. PLOS Neglected Tropical Diseases, 20(10), e0014215. https://doi.org/10.1371/journal.pntd.0014215

Image Credits: AI Generated

DOI: 10.1371/journal.pntd.0014215

Keywords: SFTS, SFTSV, severe fever with thrombocytopenia syndrome, canine-to-human transmission, family cluster, golden retriever, viral shedding, genomic analysis, tick-borne virus, Southeast China, zoonotic disease, viral carriage