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Infectivity and oocyst excretion patterns of Cryptosporidium muris in slightly infected mice
1Department of Infectious Diseases, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
Abstract:
To determine the infectivity of Cryptosporidium to hosts in slight infections, we examined the infectivity and oocyst output patterns of Cryptosporidium muris in mice inoculated with small numbers of oocysts. One of the 25 ICR mice inoculated with 2.4 x 10(1) oocysts and 19 of the 25 mice inoculated with 2.4 x 10(2) oocysts shed oocysts in the feces after inoculation. Four of the 50 mice inoculated with 2.4 x 10(1) oocysts for 10 consecutive days also shed oocysts and their OPG values were similar to that of the mice which received 2.4 x 10(2) oocysts. Consequently, it is clear that less than 10% of the mice which received 2.4 x 10(1) C. muris oocysts for 10 consecutive days.
Insights
Even small doses of Cryptosporidium muris oocysts can infect mice, with repeated low-dose exposure increasing oocyst shedding. This highlights the pathogen
Area of Science:
- Veterinary Parasitology
- Infectious Diseases
- Microbiology
Background:
- Cryptosporidium is a significant enteric protozoan parasite.
- Understanding the infectivity of low oocyst doses is crucial for disease control.
Purpose of the Study:
- To evaluate the infectivity and oocyst shedding patterns of Cryptosporidium muris in mice after inoculation with low numbers of oocysts.
Main Methods:
- Mice were inoculated with varying low doses of Cryptosporidium muris oocysts.
- Oocyst shedding in feces was monitored to determine infectivity and output patterns.
- Oocyst Per Gram (OPG) values were analyzed.
Main Results:
- Infection was established in mice receiving as few as 2.4 x 10(1) oocysts.
- A higher proportion of mice (19/25) shed oocysts when inoculated with 2.4 x 10(2) oocysts.
- Repeated low-dose inoculation (2.4 x 10(1) oocysts for 10 days) also resulted in oocyst shedding.
Conclusions:
- Low-dose Cryptosporidium muris infections are viable in mice.
- Repeated exposure to low oocyst doses can lead to significant shedding, comparable to single higher-dose infections.
- These findings have implications for understanding Cryptosporidium transmission dynamics.