Epidemiology of Severe Fever with Thrombocytopenia Syndrome in Dogs and Cats in Taiwan.

Severe Fever with Thrombocytopenia Syndrome (SFTS), caused by the SFTS Virus (SFTSV), is a global health threat. SFTSV in Taiwan has only been reported in ruminants and wild animals. Thus, we aimed to investigate the infection statuses of dogs and cats, the animals with closer human interactions. Overall, the SFTSV RNA prevalence was 23% (170/735), with dogs showing a 25.9% (111/429) prevalence and cats at 19.3% (59/306) prevalence. Noticeably, the prevalence in stray animals (39.8% 77/193) was significantly higher than in domesticated ones (17.2%, 93/542). Among the four categories analyzed, the highest SFTSV prevalence was found in the stray dogs at 53.9% (120/193), significantly higher than the 24.2% prevalence noted in stray cats. In contrast, domesticated animals exhibited similar prevalence rates, with 17.1% for dogs and 17.2% for cats. It is noteworthy that in the domesticated animal groups, a significantly elevated prevalence (45%, 9/20) was observed among cats exhibiting thrombocytopenia compared to those platelet counts in the reference range (4.8%, 1/21). The high infection rate in stray animals, especially stray dogs, indicated that exposure to various outdoor environments influences the prevalence of infections. Given the higher human interaction with dogs and cats, there is a need for proactive measures to reduce the risk associated with the infection of SFTSV in both animals and humans.

Feline mammary carcinoma-derived extracellular vesicle promotes liver metastasis via sphingosine kinase-1-mediated premetastatic niche formation.

BACKGROUND: Feline mammary carcinoma (FMC) is one of the most prevalent malignancies of female cats. FMC is highly metastatic and thus leads to poor disease outcomes. Among all metastases, liver metastasis occurs in about 25% of FMC patients. However, the mechanism underlying hepatic metastasis of FMC remains largely uncharacterized. RESULTS: Herein, we demonstrate that FMC-derived extracellular vesicles (FMC-EVs) promotes the liver metastasis of FMC by activating hepatic stellate cells (HSCs) to prime a hepatic premetastatic niche (PMN). Moreover, we provide evidence that sphingosine kinase 1 (SK1) delivered by FMC-EV was pivotal for the activation of HSC and the formation of hepatic PMN. Depletion of SK1 impaired cargo sorting in FMC-EV and the EV-potentiated HSC activation, and abolished hepatic colonization of FMC cells. CONCLUSIONS: Taken together, our findings uncover a previously uncharacterized mechanism underlying liver-metastasis of FMC and provide new insights into prognosis and treatment of this feline malignancy.

Establishment and Characterization of Feline Mammary Tumor Patient-Derived Xenograft Model.

Feline mammary tumor is a relatively commonly diagnosed neoplasm in the cat. Development of new veterinary cancer therapies is limited by the shortage of in vivo models that reproduce tumor microenvironment and metastatic progression. Four feline mammary tumor orthotopic patient-derived xenograft model (PDX) successfully established in NOD-SCID gamma (NSG) mice. The overall success rate of PDX establishment was 36% (4/11). Histological, immunohistochemical, and short tandem repeat analysis showed a remarkable similarity between patient's tumor and xenograft. The tumor grafts conserve original tumor essential features, including distant metastasis. Primary FMT-1807 cell line isolated from FMT-1807PDX tumor tissue. Tumorigenicity of FMT-1807 cells expanded from PDX was assessed by orthotopic injection into NSG mice. Mice yielded tumors which preserve the lung and liver metastasis ability. This work provides a platform for FMT translational investigation.