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Innate resistance of mice to experimental infection with Naegleria fowleri
Abstract:
The mouse system provides an excellent model for studying host resistance to Naegleria fowleri, the agent of primary amoebic meningoencephalitis. Innate resistance to infection with N. fowleri was examined with respect to infecting dose and the age, sex, and strain of mice. Intravenous inoculation with 10(7) amoebae per mouse produced 100% mortality in 9 days, whereas inoculation with fewer amoebae reduced the cumulative mortality. Male and female DUB/ICR mice of varying ages were inoculated intravenously with 2.5 X 10(5) N. fowleri per g of body weight. The youngest mice died first, with 100% mortality for both males and females, and mortality decreased with increasing age. Female mice were significantly more resistant to infection than males. Five strains of mice weighing approximately 20 g were inoculated intravenously with weight-adjusted doses; mortality ranged from 10% in C57BL/6 mice to 95% in A/HeCr mice.
Insights
Mice show varying resistance to Naegleria fowleri, the cause of primary amoebic meningoencephalitis. Younger mice and certain strains, like A/HeCr, are more susceptible, while females exhibit greater resistance.
Area of Science:
- Immunology
- Infectious Diseases
- Parasitology
Background:
- Naegleria fowleri causes primary amoebic meningoencephalitis, a rare but often fatal brain infection.
- The mouse model is crucial for understanding host immune responses and developing treatment strategies against N. fowleri.
Purpose of the Study:
- To investigate innate host resistance in mice against Naegleria fowleri.
- To determine the influence of infecting dose, age, sex, and mouse strain on N. fowleri infection outcomes.
Main Methods:
- Intravenous inoculation of mice with varying doses of N. fowleri.
- Evaluation of mortality rates based on infecting dose.
- Assessment of age- and sex-dependent resistance in DUB/ICR mice.
- Comparative analysis of mortality across five different mouse strains.
Main Results:
- A high infecting dose (10(7) amoebae/mouse) resulted in 100% mortality.
- Younger mice exhibited higher mortality rates, which decreased with increasing age.
- Female mice demonstrated significantly greater resistance to N. fowleri infection compared to males.
- Mortality varied widely among strains, from 10% in C57BL/6 to 95% in A/HeCr mice.
Conclusions:
- Mouse age, sex, and strain significantly impact susceptibility to Naegleria fowleri.
- These findings highlight the importance of host factors in primary amoebic meningoencephalitis pathogenesis.
- The mouse model effectively demonstrates variable innate resistance, aiding research into N. fowleri infections.