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Fungus Paecilomyces: a new agent in laboratory animals
I Kunstýr1, F Jelínek, U Bitzenhofer
1Central Laboratory Animal Facility, Hannover Medical School, Germany.
Laboratory Animals
|January 1, 1997
Summary
The fungus Paecilomyces, an opportunistic pathogen, was isolated from six laboratory animal species, primarily rats, often in the respiratory tract. While generally asymptomatic, it caused skin lesions in hairless mice, indicating a potential health risk.
Area of Science:
- Veterinary Mycology
- Laboratory Animal Science
- Infectious Diseases
Background:
- Paecilomyces, a fungus known to spoil food, is an opportunistic pathogen in immunocompromised humans.
- Historically, Paecilomyces has not been recognized as a significant health concern in laboratory animals.
Purpose of the Study:
- To investigate the prevalence and impact of Paecilomyces infections in various laboratory animal species.
- To assess the potential health risks posed by Paecilomyces to laboratory animal populations.
Main Methods:
- Isolation of Paecilomyces from six laboratory animal species, predominantly rats, since 1985.
- Observation of infected Specific Pathogen Free (SPF) rat breeding units and histological examination of infected rats.
- Documentation of a spontaneous skin lesion outbreak in hairless mice and assessment of respiratory signs in conventional rats.
Main Results:
- Paecilomyces was isolated from six species, with 90% of infections localized in the respiratory tract, suggesting airborne transmission.
- No adverse health effects or lesions were observed in SPF rats despite long-term Paecilomyces presence.
- A self-limiting outbreak of papular skin lesions occurred in hairless mice; the fungus played a secondary role in rat respiratory disease.
Conclusions:
- Paecilomyces, particularly P. variotti, is an emerging opportunistic pathogen in laboratory animals, primarily affecting the respiratory system.
- While often asymptomatic in rats, it can cause clinical signs like skin lesions in susceptible hosts (hairless mice).
- Given its resistance to disinfectants, toxigenicity, and potential harm to humans, Paecilomyces warrants monitoring as a potential laboratory animal health risk.