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Temporal study of acquired resistance in infections of mice with Giardia muris
Abstract:
Swiss CD-1 mice infected with cysts of Giardia muris are protected against a challenge infection. A temporal study of this phenomenon was undertaken using two different approaches. First, the time needed for mice to acquire resistance was assessed by terminating the first infection using metronidazole on days 3, 6, 12, 24 or 48. These animals received a challenge infection 7 days later. Second, the duration of the protection was determined by giving mice a challenge infection on days 30, 60, 90, 120 or 150 after the primary infection. In all cases, a significant reduction in both cyst output and trophozoite numbers in the small intestine was observed after challenge. The reduction in cyst output following challenge was similar to the reduction in trophozoite numbers. The acquired resistance of some inbred strains of mice to G. muris was similar to that of CD-1 Swiss mice. These results show that mice can acquire a significant resistance against G. muris even after a short period of contact with the parasite (3 days) and that the resistance may last up to 21 weeks.
Insights
Mice infected with Giardia muris develop resistance quickly, within 3 days, and this protection against reinfection can last up to 21 weeks. This study quanties the timing of resistance acquisition and duration in mice.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Giardia muris infection in mice confers protection against subsequent challenge.
- Understanding the temporal dynamics of this acquired immunity is crucial for developing effective control strategies.
Purpose of the Study:
- To determine the time required for mice to acquire resistance to Giardia muris.
- To assess the duration of this protective immunity following an initial infection.
Main Methods:
- Swiss CD-1 mice were infected with Giardia muris cysts.
- Resistance acquisition was assessed by treating primary infections with metronidazole at various time points (3-48 days) followed by challenge infection.
- Protection duration was evaluated by challenging mice at different intervals (30-150 days) post-primary infection.
Main Results:
- Mice acquired significant resistance to Giardia muris within 3 days of initial infection.
- Protective immunity against G. muris challenge persisted for up to 21 weeks (150 days).
- A reduction in both cyst output and trophozoite numbers was observed after challenge, indicating effective immunity.
Conclusions:
- Mice can develop substantial resistance to Giardia muris even after a brief exposure.
- The acquired immunity against Giardia muris is long-lasting, persisting for several weeks.