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Aspergillus fumigatus dsRNA virus promotes fungal fitness and pathogenicity in the mammalian host

Summary

A virus that infects the fungus Aspergillus fumigatus (which causes serious lung infections in humans) actually makes the fungus more dangerous by improving its ability to survive stress and spread disease. Scientists found that removing this virus from the fungus made infections less severe in mice. They also discovered that antiviral drugs like ribavirin could potentially be used to weaken these virus-infected fungi and improve patient survival.

Background

Aspergillus fumigatus causes approximately 65% of invasive fungal infections in humans with mortality rates approaching 50%. Mycoviruses (viruses infecting fungi) are known to modulate virulence in plant pathogens, but their impact on fungal pathogenesis in mammals remains largely unexplored.

Objective

To investigate how infection with A. fumigatus polymycovirus-1M (AfuPmV-1M), a double-stranded RNA mycovirus, affects fungal fitness, stress tolerance, and pathogenicity in the mammalian host using both in vitro and in vivo models.

Results

AfuPmV-1M-infected strains demonstrated enhanced survival under oxidative, heat, pH, and osmotic stress. The virus upregulated stress granule components, antioxidant proteins, and conidiation-related genes. Virus-infected strains exhibited increased lung fungal burden and mortality in mice, while antiviral ribavirin treatment reduced viral load and improved mouse survival.

Conclusion

AfuPmV-1M functions as a ‘molecular backseat driver’ enhancing A. fumigatus fitness and virulence through modulation of stress responses, conidiation, and melanin production. Antiviral treatments targeting mycoviral replication represent a novel therapeutic strategy against mycovirus-infected pathogenic fungi.
  • Published in:Nature Microbiology,
  • Study Type:Experimental Study,
  • Source: PMID: 40813922; DOI: 10.1038/s41564-025-02096-3
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