Severe Fever with Thrombocytopenia Syndrome in Cats and Its Prevalence among Veterinarian Staff Members in Nagasaki, Japan

Abstract

In this study, we investigated severe fever with thrombocytopenia syndrome (SFTS) virus (SFTSV) infection in cats in Nagasaki, Japan. In total, 44 of 133 (33.1%) cats with suspected SFTS were confirmed to be infected with SFTSV. Phylogenetic analyses of SFTSV isolates from cats indicated that the main genotype in Nagasaki was J1 and that unique reassortant strains with J2 (S segment) and unclassified genotypes (M and L segments) were also present. There were no significant differences in virus growth in cell cultures or fatality in SFTSV-infected mice between the SFTSV strains that were isolated from recovered and fatal cat cases. Remarkably, SFTSV RNAs were detected in the swabs from cats, indicating that the body fluids contain SFTSV. To evaluate the risk of SFTSV infection when providing animal care, we further examined the seroprevalence of SFTSV infection in veterinarian staff members; 3 of 71 (4.2%) were seropositive for SFTSV-specific antibodies. Our results provide useful information on the possibility of using cats as sentinel animals and raised concerns of the zoonotic risk of catching SFTSV from animals.

Animal Model of Severe Fever With Thrombocytopenia Syndrome Virus Infection

“…Therein, immunization with recombinant SFTSV NSs protein could induce a high titer of anti-NSs antibody in sera and yet it could not promote SFTSV clearance in mice (Liu et al, 2015). Two recombinant viral vectors including a recombinant rabies virus (RABV) expressing SFTSV Gn (rLBNSE-Gn) and a recombinant human adenovirus type 5 co-expressing RABV G and SFTSV Gn (Ad5-G-Gn) were designed as potential bivalent Chen et al, 2012Chen et al, , 2020Jin et al, 2012;Liu et al, 2015;Sun et al, 2015;Matsuno et al, 2017;Park S. J. et al, 2019; vaccines against SFTSV and RABV to take precaution against possibly dangerous contacts and infection between animals and humans Yamanaka et al, 2020;Zhao et al, 2020;Ando et al, 2021;Tian et al, 2021). Additionally, a recent study showed that SFTSV can be transmitted vertically across the placental barrier of the pregnant maternal mice (C57BL/6) to the fetuses, resulting in widely distributed infection in multiple organs of the fetuses (Chen et al, 2020).…”

“…Severe fever with thrombocytopenia syndrome (SFTS) as an emerging tick-borne infectious disease is an enormous threat to human life and health due to its high case fatality rates of 12–30% and the transmission routes of not only tick bites but also human-to-human and animal-to-human contacts ( Bao et al, 2011 ; Xu et al, 2011 ; Yu et al, 2011 ; Zhang et al, 2011 ; Jung et al, 2019 ; Kang et al, 2019 ; Park E. S. et al, 2019 ; Yamanaka et al, 2020 ; Ando et al, 2021 ; Tsuru et al, 2021 ). SFTS is characterized by fever, thrombocytopenia, leukocytopenia, hemorrhage, and gastrointestinal symptoms ( Yu et al, 2011 ).…”

Vectors, Hosts, and the Possible Risk Factors Associated with Severe Fever with Thrombocytopenia Syndrome

“…One meta-analysis study found the pooled seroprevalence of anti-SFTSV antibodies was 45.70% in goats and sheep, 36.70% in cattle, 29.50% in dogs, 9.60% in chickens, 3.20% in rodents, and 3.20% in pigs, respectively [ 32 ]. In Table 2 , SFTSV antibodies or RNA have been detected positive in more than ten kinds of domesticated animals, including dogs, goats, cattle, and pigs [ 4 , 6 , 11 , 12 , 17 , 33 , 39 , 41 , 42 ]. Among them, the highest antibody-positive rate was seen in cattle (97.92%) of China [ 36 ].…”

“…Additionally, high SFTSV antibody rates were also found in goats (74.77%), chickens (52.14%) [ 37 ], sheep (69.74%), dogs (68.18%), ducks (19.67%) [ 36 ], minks (8.43%) [ 6 ], cats (1.92%) [ 38 ], pigs (4.66%), and geese (1.67%) [ 35 ]. Besides, in ROK and China, SFTSV RNA was also found to be positive in cats (33.08%) [ 42 ], cattle (2.08%) [ 36 ], goats (1.93%) [ 39 ], pigs (1.67%) [ 41 ], and dogs (0.88%) [ 38 ]. Domestic animals, especially the companion animals, could increase the epidemic threat of SFTS due to the close interaction with humans [ 43 ].…”

“…SFTS cases could also occur in hospital in other ways, such as needle-stick injury in medical activities [ 76 ] and handling sick animals [ 77 ]. One study examining the seroprevalence of SFTSV infection in veterinarian staff members found that 3 of 71 (4.2%) were seropositive for SFTSV-specific antibodies [ 42 ]. Consequently, the strict adherence to routine blood and body fluid precautions is necessary when HCWs have contact with any patient.…”