Experimental infection of dogs with severe fever with thrombocytopenia syndrome virus: Pathogenicity and potential for intraspecies transmission

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is caused by infection with Dabie bandavirus [formerly SFTS virus (SFTSV)] and is an emerging zoonotic disease. Dogs can be infected with SFTSV, but its pathogenicity and transmissibility have not been fully elucidated. In experiment 1, immunocompetent dogs were intramuscularly inoculated with SFTSV. In experiment 2, immunosuppressed dogs (immunosuppressed group; oral azathioprine 5 mg/kg/day for 30 days) were intramuscularly inoculated with SFTSV.Both immunosuppressed and immunocompetent contact dogs were co-housed with the SFTSV-inoculated dogs that had been immunosuppressed. Immunocompetent SFTSV-infected dogs did not show any clinical symptom. However, immunosuppressed SFTSV-infected dogs showed high fever and weight loss without lethality. In all SFTSVinfected dogs, viral RNA could be measured in the serum only after 3 days post infection (DPI) and neutralizing antibodies were detected in the serum beginning 9 DPI. SFTSV shedding in the urine and faeces of some infected dogs occurred between 4 and 6 DPI. The immunocompromised SFTSV-infected dogs showed thrombocytopenia beginning 3 DPI to the end of the experiment (24 DPI). We confirmed SFTSV transmission to one of three immunocompetent co-housed dogs. This dog showed a high fever, weight loss, and shed viral RNA by urine. Viral RNA and neutralizing antibodies were also detected in the serum. These results demonstrated that intramuscular inoculation with SFTSV induced minor clinical symptoms in dogs, and intraspecies SFTSV transmission in dogs can occur by contact.

Clinical features and epidemiology of severe fever with thrombocytopenia syndrome in dogs in the Republic of Korea: an observational study (2019–2020)

“…In feline SFTS, thrombocytopenia was observed in 91.7% (22/24) of cases (Matsuu et al 2019). Similar to the results observed in the previous study of canine SFTS, in our study, even when thrombocytopenia occurred, severe anemia occurred in only one dog, and most of the dogs did not show anemia (Han et al 2020;Nam et al 2020;Park et al 2021). These findings are comparable to those reported for feline SFTS (Matsuu et al 2019).…”

“…Fever was observed in 57.1% dogs, with severe fever (over 40 °C) occurring only in two dogs. In a previous study in which dogs were experimentally infected with SFTSV, immunosuppressed dogs showed high fever (above 40 °C) while immunocompetent dogs showed slightly elevated fever (above 39.5 °C) (Park et al 2021). Only one immunocompetent dog had high fever.…”

“…To our knowledge, clinical infection has been reported only in two dogs with natural infection and 16 dogs with experimental infection (Han et al 2020;Nam et al 2020;Park et al 2021). Dogs typically exhibit fever, anorexia, depression, vomiting, and pink eyes.…”

“…Moreover, antibodies against the SFTS virus (SFTSV) have been identified in veterinary hospital workers in Japan (Kirino et al 2021). Cases of presumed transmission of SFTSV from domestic dogs to humans have been reported in the Republic of Korea (ROK), while an in vivo study in dogs confirmed that intraspecies SFTSV transmission could occur by contact; these findings suggest that infection can occur in animals as well as humans (Chung et al 2020;Park et al 2021).…”

Hedgehogs are the major amplifying hosts of severe fever with thrombocytopenia syndrome virus

“…inoculation with 10 7 PFU of SFTSV, which lasted for only less than 24 h(Jiao et al, 2015). Similarly, beagle dogs intramuscularly inoculated with 2.51 × 10 7 TCID50 of SFTSV, only had a detectable viremia at d 3(S. C. Park et al, 2021).…”