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Outbreak of fever caused by Streptobacillus moniliformis
M B McEvoy1, N D Noah, R Pilsworth
1Public Health Laboratory Service, Communicable Disease Surveillance Centre, Colindale, London.
Abstract:
A large outbreak of streptobacillary fever, confirmed by the isolation of Streptobacillus moniliformis from blood culture, affected 304 people, 43% of the total population of 700 in a boarding school. Raw milk initially appeared to be the vehicle of infection, but detailed epidemiological investigation showed significant statistical associations between the development of illness and the consumption of both milk and water. Further analysis showed that the association with water was independent of that with milk and that water was therefore more likely to have been the vehicle of infection. Opportunity for contamination of water by rats existed, although contamination was not confirmed by the isolation of S moniliformis from either rats or the water supply.
Insights
A large outbreak of streptobacillary fever infected 304 people in a boarding school. Water, not milk, was identified as the likely source of the Streptobacillus moniliformis infection.
Area of Science:
- Epidemiology
- Infectious Diseases
- Microbiology
Background:
- A significant outbreak of streptobacillary fever occurred in a boarding school.
- The causative agent, Streptobacillus moniliformis, was confirmed via blood culture.
- The outbreak affected a substantial portion (43%) of the school's population.
Purpose of the Study:
- To identify the vehicle of infection in a large streptobacillary fever outbreak.
- To differentiate between suspected sources of Streptobacillus moniliformis transmission.
Main Methods:
- Epidemiological investigation including statistical analysis of consumption data.
- Microbiological analysis involving blood cultures, and attempts to isolate bacteria from suspected sources.
- Case-control study to assess risk factors associated with illness.
Main Results:
- Initial suspicion pointed to raw milk, but further investigation implicated water.
- Statistical analysis revealed a significant association between illness and water consumption, independent of milk consumption.
- Despite evidence of potential contamination routes (rats), Streptobacillus moniliformis was not isolated from water or rats.
Conclusions:
- Water was the most probable vehicle for the Streptobacillus moniliformis outbreak.
- Rats may have been a source of contamination, but this was not microbiologically confirmed.
- Effective public health interventions require accurate identification of disease transmission routes.