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Comparison of Streptococcus zooepidemicus and influenza virus pathogenicity in mice by three pulmonary exposure
R L Sherwood1, P T Thomas, C Y Kawanishi
1Life Sciences Research, IIT Research Institute, Chicago, Illinois 60616.
Abstract:
Pulmonary infections may be induced in experimental animals by using several exposure routes. Inhalation of microbial aerosols is often viewed as the most relevant exposure route, although the comparability of either intranasal (i.n.) or intratracheal (i.t.) inoculation to aerosol inhalation is unclear. In these studies, the infection of mice with either Streptococcus zooepidemicus or influenza virus was compared following i.n., i.t., or aerosol challenge. The 50% lethal dose was determined by each exposure route for both microbes, and the organ clearance of a 50% lethal dose was determined. Mice were as or more sensitive to bacterial or viral infection following i.n. or i.t. instillation as compared with aerosol challenge. Organ clearance patterns of virus or bacteria varied slightly with exposure route.
Insights
Intranasal or intratracheal inoculation in mice is as effective as aerosol inhalation for inducing pulmonary infections. This finding impacts how researchers study bacterial and viral infections in animal models.
Area of Science:
- Comparative immunology
- Infectious disease modeling
- Microbiology
Background:
- Pulmonary infections are critical in experimental research.
- Aerosol inhalation is considered the most relevant exposure route for microbial challenge.
- The efficacy of intranasal (i.n.) and intratracheal (i.t.) inoculation compared to aerosol inhalation remains unclear.
Purpose of the Study:
- To compare the efficacy of i.n., i.t., and aerosol challenge routes in inducing pulmonary infections in mice.
- To determine the 50% lethal dose (LD50) for Streptococcus zooepidemicus and influenza virus via different exposure routes.
- To analyze organ clearance patterns following infection via distinct exposure routes.
Main Methods:
- Mice were challenged with S. zooepidemicus or influenza virus using i.n., i.t., or aerosol routes.
- The LD50 was determined for each microbe and exposure route.
- Organ clearance of a determined LD50 was assessed post-infection.
Main Results:
- Mice exhibited equal or greater sensitivity to bacterial and viral infections via i.n. or i.t. instillation compared to aerosol challenge.
- The LD50 values varied across the different exposure routes for both pathogens.
- Organ clearance kinetics for bacteria and viruses showed minor variations depending on the exposure route.
Conclusions:
- Intranasal and intratracheal inoculation are viable and effective methods for inducing pulmonary infections in mice, comparable to aerosol inhalation.
- These findings provide valuable insights for selecting appropriate exposure routes in animal models for studying pulmonary infections.
- Understanding route-specific infection dynamics is crucial for accurate modeling of bacterial and viral pathogenesis.