#18,523
Also known as the Dabie bandavirus, SFTS is believed be carried and transmitted by the Asian Longhorned tick (along with Amblyomma testudinarium & Ixodes nipponensis).
The virus was first discovered in China in 2009, but has subsequently been found in Japan, South Korea and Vietnam - and in 2019 was detected for the first time in Taiwan.
- While primarily spread by ticks, there is evidence that the virus can also be transmitted from from animals-to-humans (see EID Journal Direct Transmission of SFTS from Domestic Cat to Veterinary Personnel).
- And also from human-to-human (see Nosocomial person-to-person transmission of severe fever with thrombocytopenia syndrome) either through aerosols or close contact with infected body fluids. See also:
As we've discussed previous (as recently as yesterday), fur farms make excellent `disease factories' due to their high animal density and often poor biosecurity.
We describe an outbreak of SFTS on a mink farm situated in Shandong, China. During late May through early July, 2022, >1,500 minks on this farm exhibited symptoms such as vomiting, diarrhea, and, in a small number, limb convulsions.
Most minks exhibiting clinical manifestations died of the disease
All of which brings us to another report on a much larger outbreak of SFTS in Arctic foxes raised on farms in Shandong and Liaoning provinces, China. This report not only finds the virus is evolving, it has marked tropism for multiple organ systems, including the brain.
The link, Abstract, and a couple of small excerpts from the study follow, but the full article is well worth reading. I'll have a brief post script when you return.
Jian Sun,Lei Qian,Delong Li,Xiurong Wang,Hong Zhou,Cixiu Li, show all
Article: 2447610 | Accepted author version posted online: 27 Dec 2024
ABSTRACT
The role of farmed animals in the viral spillover from wild animals to humans is of growing importance. Between July and September of 2023 infectious disease outbreaks were reported on six Arctic fox (Vulpes lagopus) farms in Shandong and Liaoning provinces, China, which lasted for 2-3 months and resulted in tens to hundreds of fatalities per farm.
Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) was identified in tissue/organ and swab samples from all the 13 foxes collected from these farms. These animals exhibited loss of appetite and weight loss, finally resulting in death. In autopsy and histopathology, prominently enlarged spleens and extensive multi-organ hemorrhage were observed, respectively, indicating severe systemic effects.
Viral loads were detected in various tissues/organs, including brains from 12 of the 13 foxes. SFTSV was also detected in serum, anal swabs, as well as in environmental samples, including residual food in troughs used by dying foxes in two follow-up studies at two farms. The 13 newly sequenced SFTSV genomes shared >99.43% nucleotide identity with human strains from China.
Phylogenetic analyses showed that the 13 sequences belonged to three genotypes, and that two sequences from Liaoning were genomic reassortants, indicative of multiple sources and introduction events.
This study provides the first evidence of SFTSV infection, multi-tissue tropism, and pathogenicity in farmed foxes, representing an expanded virus host range. However, the widespread circulation of different genotypes of SFTSV in farmed animals from different provinces and the diverse transmission routes, highlight its increasing and noticeable public health risk in China.
(SNIP)
Of note, SFTSV RNA was present in multiple organs of the infected foxes, including the heart, liver, spleen, lungs, kidneys, brain, and intestine (14, 48). In particular, spleen was found to be the major target organ, which exhibited especially high viral loads. This is consistent with earlier observations in animal models (e.g., mice), where high viral loads in the spleen were typically associated with severe pathological changes (49). Further, the neurotropism of SFTSV was previously reported in an aged ferret model (48), and SFTSV RNA was also found in the brain in 12 of the 13 dead foxes in this study.
However, the symptoms of neurotropism of SFTSV in the infected foxes remain to be determined. Viral RNA was also detected in tissues such as the trachea, nasal turbinate, bladder, and pancreas, which have not been previously reported. Furthermore, SFTSV nucleic acid was positive in oral swabs and serum in the case studies and the follow-up studies.
These results suggest that foxes could be potent hosts for SFTSV, which is crucial for assessing the potential of the virus to spread among wildlife populations.
(SNIP)
In summary, this study describes concurrent SFTSV outbreaks in multiple fox farms in Shandong and Liaoning provinces, expanding our understanding of viral host range and revealing the complex transmission dynamics of SFTSV. SFTSV RNA was detected in many different tissues/organs in the infected foxes, and our results highlight the potential role of wildlife in the spread of emerging infectious diseases (57).
Considering the close contact between humans and animals in the farms, enhancing surveillance and biosecurity measures to mitigate the risk of zoonotic diseases in fur-producing industry is of clear importance.
While that might eventually happen in the wild, fur farms are essentially unmonitored GOF (Gain of Function) experiments, conducted on a global scale, with little regard for biosecurity.
Making fur farming a dangerous luxury, whose ultimate costs to society may be far higher than we currently realize.
