Study Provides Insights into SARS-CoV-2 Zoonotic Transmission

In the ongoing exploration of viral transmission dynamics, researchers at the University of California, Riverside, have investigated the intricate web of zoonosis in mink, shedding light on potential implications for public health. Their study, published in Frontiers in Microbiology, specifically delves into the role of TMPRSS2, a crucial enzyme in the viral fusion entry of SARS-CoV-2 in humans.

Unlike in humans, the researchers discovered that TMPRSS2 is nonfunctional in mink, suggesting a distinctive mode of SARS-CoV-2 entry. Ann Song, the doctoral student leading the research, highlighted that mink lung cells are infected through the endocytosis pathway, unlike the TMPRSS2 fusion pathway observed in human cells. This discrepancy underscores the necessity for comprehensive investigations into viral entry mechanisms across various species.

Viral fusion, where the virus membrane fuses with the host cell's plasma membrane, is a critical aspect of infection. Song explained that mink TMPRSS2 lacks the functional domain, making it ineffective in SARS-CoV-2 fusion to host cells. The study emphasizes the variation in SARS-CoV-2 entry among different mammalian species and tissue types, challenging assumptions about universal mechanisms.

Zoonosis, the transmission of pathogens between species, is a growing public health concern due to the potential emergence of mutated virus forms. Lead author Prue Talbot cautioned against underestimating the risk of spillover and spillback of SARS-CoV-2 in various mammalian species, noting the potential for deadly mutants to arise. As an example, she highlighted the infection of deer herds, posing a risk of spillback to humans.