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Experimental blastomycosis pneumonia in mice by infection with conidia
1Evans Memorial Department of Clinical Research, Boston University Medical Center, Massachusetts.
Abstract:
We describe a murine model of acute blastomycosis pneumonia induced by Blastomyces dermatitidis conidia. Anesthetized mice were infected by placing a droplet containing conidia suspended in sterile saline on the nares and allowing the suspension to be aspirated into the lungs. Conidia were obtained from mycelia derived from the yeast forms of two well characterized strains of B. dermatitidis, ATCC 26199 and 26197. ATCC 26199 yeast and conidia were highly virulent in BALB/cByJ mice whereas both forms of ATCC 26197 were incapable of causing disease in 60 days. Conidia and yeasts of the virulent strain caused pathologic changes primarily in the lungs, whereas no abnormalities were seen in the lungs, or elsewhere, in mice infected with the a virulent strain. Small numbers of ATCC 26199 yeast forms were found in scattered foci in liver and kidneys, but no inflammatory reaction surrounded the fungus. This murine model of acute blastomycosis pneumonia mimics the acute disease in humans and is initiated with the naturally infectious particle.
Insights
Researchers developed a new mouse model for acute blastomycosis pneumonia using Blastomyces dermatitidis conidia. This model accurately mimics human disease progression and aids in studying fungal pneumonia.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Animal Models
Background:
- Blastomycosis is a serious fungal infection primarily affecting the lungs.
- Developing accurate animal models is crucial for understanding blastomycosis pathogenesis and testing treatments.
Purpose of the Study:
- To establish and characterize a murine model of acute blastomycosis pneumonia.
- To utilize the naturally infectious particle of Blastomyces dermatitidis for disease induction.
Main Methods:
- Infection of BALB/cByJ mice via intranasal instillation of Blastomyces dermatitidis conidia.
- Utilized two strains: ATCC 26199 (virulent) and ATCC 26197 (avirulent).
- Assessed pathological changes in lungs and other organs post-infection.
Main Results:
- The virulent strain (ATCC 26199) induced acute pneumonia with significant lung pathology.
- The avirulent strain (ATCC 26197) did not cause disease.
- Minimal dissemination of the virulent strain to the liver and kidneys was observed without inflammation.
Conclusions:
- This murine model effectively replicates acute blastomycosis pneumonia seen in humans.
- The model uses the infectious conidial form, providing a relevant system for studying fungal pneumonia.
- The differential virulence of B. dermatitidis strains was confirmed in this model.