Researchers conducted a metatranscriptomic investigation of Chinese farmed fur mammals suspected to have died from viral diseases to elucidate if these animals served as a reservoir for viral strains with zoonotic spillover potential. This comprehensive analysis highlights the critical role of fur animals as potential vectors for future pandemics.
Next-generation sequencing of tissues from 461 individual samples collected across 28 species revealed 125 vertebrate-associated virus species from 20 viral families, significantly higher than previously estimated.
Notably, the study identified 36 novel viruses and at least 39 viruses meeting the criteria for high-risk transmission, including seven coronaviruses, depicting cross-species transmission and zoonotic spillover potential. This includes the identification of a novel MERS-like coronavirus in mink and three subtypes of influenza A virus, further expanding the known host range for these pathogens.
The study expanded the known ranges of several virus species and identified previously unknown hosts as disease reservoirs. It highlights mink (reservoir for 23 virus species from 11 viral families), raccoon dogs (19 virus species from 14 viral families), Arctic foxes (13 virus species from 6 viral families), and guinea pigs (potential intermediate host for pathogen transmission) as animals requiring intensive surveillance lest they serve as the trigger for a viral outbreak of pandemic proportions.
Co-infection between different mammalian hosts was observed to be common, with 15 virus species transmitting between fur animals of different orders. For example, the study detected Japanese encephalitis virus in guinea pigs, a virus typically associated with human and swine infections. This finding underscores the broad host spectrum and significant cross-species transmission potential of the identified viruses.
Results
Phylogenetic analysis revealed 125 vertebrate-associated virus species (20 families) across the 461 samples, including 36 previously undescribed species (12 families) absent from the International Committee on Taxonomy of Viruses. Alarmingly, zoonotic viral risk criteria highlighted 13 of these novel species as 'high-risk,' emphasizing the need for further research into their epidemiology.
Three hundred thirty-five host samples (>72%) were found positive for at least one virus species, with the study demonstrating a >60% increase in virus host range over previously known. Most fur animal species investigated were found to play host to between 2 and 23 virus species.
Mink, guinea pigs, raccoon dogs, and Arctic foxes were found to be the most generalist hosts, acting as reservoirs for 23, 20, 19, and 13 virus species, respectively.
Of particular concern is the identification of Pipistrellus bat coronavirus HKU5-like viruses in mink, highlighting a cross-order transmission event with significant zoonotic potential. Additionally, novel influenza A viruses, such as H5N6 and H6N2, were detected in mink and muskrat, respectively, indicating these animals could serve as important intermediate hosts in viral transmission chains.
Co-infection between interspecific mammalian hosts was observed to be commonplace – 15 virus species were found to transmit between fur animals of different orders, 11 of which display the potential for zoonotic transmission to humans.
Together, these findings highlight farmed fur animals as significant reservoirs of potential epi- or pandemic-triggering viral pathogens, underscoring the need for extensive surveillance and research efforts to restrict the transmission of these viromes to humans and other domesticated or wild mammalian populations.
Conclusion
The present study identified Chinese farmed fur animals (28 species) as unprecedented reservoirs of more than 125 virus species (20 families), 36 novel to science, and at least 13 categorized as 'high-risk' for their zoonotic transmission potential to humans.
Furthermore, the study revealed high-priority species (e.g., guinea pigs, muskrats, and mink) and frequent co-infections between mammals and humans, highlighting the need for enhanced surveillance and research to avoid and address future zoonotic outbreaks.
The study's findings provide crucial reference data for understanding the potential for fur animals to trigger future outbreaks, emphasizing the importance of ongoing virological surveillance to protect public health.
Source:
https://www.news-medical.net/news/20240909/Chinese-farmed-fur-animals-found-to-harbor-dozens-of-novel-viruses.aspx