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Trichuris muris Infection: A Model of Type 2 Immunity and Inflammation in the Gut
Published on: May 24, 2011
Evaluation of Therapeutic Approaches for the Treatment of Spironucleus muris in Mice
George B Voros1, Robert V Blair2, David D Andrews3
1Department of Comparative Medicine, Tulane University, New Orleans, Louisiana and Biological Resources Unit, Cleveland Clinic, Cleveland, Ohio;,
Abstract:
Spironucleus muris is an intestinal protozoal pathogen that can infect various species of rodents. The infection can have a wide range of clinical presentations, from no signs of disease to death. In addition, this pathogen can adversely affect research results, especially immunologic and gastrointestinal studies. For these reasons, institutions may exclude Spironucleus muris. However, despite rigorous efforts to keep this pathogen out, it can be common in rodent colonies. The current recommended approach to eradicating this pathogen is by testing and culling positive animals. A similar organism, Giardia muris, has been effectively eliminated by using chemotherapeutics. Therefore, the objective of this study was to determine whether S. muris is also susceptible to chemotherapeutics. Naturally infected mice were randomized to treatment groups after confirmation of positive infection via PCR. Mice received either metronidazole, fenbendazole, a combination of metronidazole-fenbendazole, or acidified water (control) treatments for a period of 4 wk. Each week fecal testing of S. muris was performed via PCR to evaluate the effectiveness of the treatments. At the end of the 4 wk period, mice were euthanized via CO₂ inhalation and segments of the proximal gastrointestinal tract were submitted for histopathologic analysis. Treatment with metronidazole or fenbendazole alone or in combination, failed to clear S. muris infected mice. After 4 wk of treatment, none of the mice given fenbendazole via sucralose medicated gel were positive by either PCR or histopathology; however, this finding is most likely due to intermittent shedding rather than chemotherapeutic success. Therefore, the recommendation remains to test-and-cull or rederive mice as necessary to eliminate S. muris from laboratory animal facilities.
Insights
Chemotherapy failed to eliminate Spironucleus muris in mice. Current recommendations for Spironucleus muris eradication in research settings remain test-and-cull or rederivation.
Area of Science:
- Veterinary Parasitology
- Laboratory Animal Science
- Microbiology
Background:
- Spironucleus muris is an intestinal protozoal pathogen affecting rodents, causing variable clinical signs and impacting research outcomes.
- Exclusion of S. muris is common in research institutions due to its prevalence and detrimental effects on studies.
- Current eradication strategies rely on testing and culling, a method that is labor-intensive and costly.
Purpose of the Study:
- To investigate the efficacy of chemotherapeutic agents in eradicating Spironucleus muris infections in mice.
- To determine if metronidazole, fenbendazole, or a combination thereof could serve as alternatives to culling for S. muris elimination.
- To assess the impact of these treatments on S. muris shedding and infection levels.
Main Methods:
- Naturally infected mice were confirmed positive for S. muris via PCR.
- Mice were randomized into four groups: metronidazole, fenbendazole, a combination of both, or acidified water (control).
- Fecal samples were tested weekly via PCR for 4 weeks, followed by histopathological analysis of the gastrointestinal tract.
Main Results:
- Metronidazole and fenbendazole, alone or in combination, did not effectively clear S. muris infections.
- While some mice treated with fenbendazole showed negative PCR and histopathology results, this was attributed to intermittent shedding rather than successful eradication.
- No chemotherapeutic regimen tested proved effective in eliminating S. muris from infected mice.
Conclusions:
- Chemotherapeutic treatment with metronidazole or fenbendazole is not an effective method for eradicating Spironucleus muris in mice.
- The established methods of test-and-cull or rederivation remain the recommended approaches for eliminating S. muris from laboratory animal facilities.
- Further research into alternative eradication strategies may be warranted, but current evidence supports traditional methods.
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