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Pneumocystis carinii f. sp. hominis is not infectious for SCID mice
Isabelle Durand-Joly1, El Moukhtar Aliouat, Céline Recourt
1Ecologie du Parasitisme, Institut Pasteur de Lille, 1 rue du Prof-Calmette-BP 245, 59019 Lille, France. isabelle.joly@pasteur-lille.fr
Abstract:
The infectious power of Pneumocystis carinii f. sp. hominis was explored by inoculating SCID mice intranasally with either P. carinii f. sp. hominis or P. carinii f. sp. muris isolates. Only mice inoculated with mouse parasites developed Pneumocystis pneumonia, as assessed by microscopy and PCR. These results suggest that humans do not contract pneumocystosis from animals.
Insights
Humans likely do not contract Pneumocystis pneumonia from animals. Studies show that only mice infected with mouse Pneumocystis parasites developed the condition, not those exposed to human-specific strains.
Area of Science:
- Medical Mycology
- Immunology
- Infectious Diseases
Background:
- Pneumocystis pneumonia (PCP) is an opportunistic infection primarily affecting immunocompromised individuals.
- The transmission routes and host specificity of Pneumocystis species remain incompletely understood.
- Pneumocystis carinii is a fungal pathogen that causes PCP in various mammalian hosts.
Purpose of the Study:
- To investigate the infectious potential and host specificity of Pneumocystis carinii f. sp. hominis.
- To determine if zoonotic transmission of Pneumocystis pneumonia from animals to humans is a significant risk.
Main Methods:
- Severe Combined Immunodeficient (SCID) mice were intranasally inoculated with Pneumocystis carinii f. sp. hominis (human-associated) or Pneumocystis carinii f. sp. muris (mouse-associated) isolates.
- Infection was assessed using microscopy and Polymerase Chain Reaction (PCR) to detect Pneumocystis DNA.
- Clinical signs and pathological changes consistent with Pneumocystis pneumonia were evaluated.
Main Results:
- SCID mice inoculated with Pneumocystis carinii f. sp. muris developed Pneumocystis pneumonia.
- Mice inoculated with Pneumocystis carinii f. sp. hominis did not develop detectable Pneumocystis pneumonia.
- Microscopy and PCR confirmed the presence of Pneumocystis in infected mice, with species-specific identification.
Conclusions:
- Pneumocystis carinii f. sp. hominis isolates are not infectious to SCID mice, suggesting a lack of cross-species infectivity.
- These findings indicate that humans are unlikely to contract Pneumocystis pneumonia through direct contact with infected animals.
- The study supports the concept of host-specific Pneumocystis parasites, limiting zoonotic transmission of PCP.