Mice and rats can suffer from a number of health problems, but Tyzzer’s disease is usually seen in mice, although rats are also susceptible. It is caused by the bacterium Clostridium piliforme (formerly called Bacillus piliformis), which is usually transmitted by eating contaminated food or water.
The bacteria lives in the intestine and spreads from animal to animal through faecal contamination of food and water. The bacterium can also survive in spore form for extremely long periods in soil, bedding and feed and is, therefore, highly resistant. Tyzzer’s disease can cause cell death in the liver and intestinal tract of many small mammals, and can also affect the heart and central nervous system.
Signs of infection are often inapparent but may include dehydration, depression/lethargy and rough haircoat. Sudden death (within 48 hours of initial signs) in young animals or those stressed by overcrowding, poor hygiene, extreme environmental temperatures, parasitic infections or malnutrition.
Another form of the disease results in chronic wasting and death. Diarrhoea may or may not be noted.
C. piliforme only grows inside cells, therefore it won’t grow on routine culture media in a laboratory. A blood test is available, but false positive test results can occur making it an unreliable test. Unfortunately the disease is difficult to diagnose before death, and is much easier to diagnose during a post-mortem examination, by using stains on the intestine and liver and then examining them under the microscope. Sacrificing 1-2 individuals of a large group and performing post-mortems on them is recommended to successfully treat and perhaps spare the majority of the group.
Specific antibiotics are available, but must be used early in the course of the disease. However, treatment is generally aimed at supportive care, including fluids, good nutrition and providing the optimal environmental conditions. In young and stressed animals, treatment is usually unsuccessful.
Some evidence indicates that this disease can be transmitted to pregnant women, therefore all necessary precautions should be taken to prevent this possibility.