Clostridium botulinum is a gram-positive, rod-shaped, anaerobic, spore-forming bacterium which is capable of producing a potent toxin that causes Botulism. There are several types of
C. botulinum which exist (A, B, C alpha, C beta, D, E, F and G). Birds are affected mainly by type C, and occasionally A and E.
C. botulinum type C is found worldwide, wherever large populations of wild and domestic birds are reside.
Transmission: Poultry develop botulism from ingestion of the toxin produced by
C. botulinum under certain environmental conditions. This can occur from a variety of ways:
- Ingestion of maggots containing varying levels of the toxin, after feeding on dead birds.
- Ingestion of toxin laden invertebrates.
- Ingestion of soil or water containing the toxin.
- Feeding birds home-canned vegetables.
Seasonal influence: Temperature is a critical factor in the multiplication of
C. botulinum in the environment, and outbreaks are more likely to take place during the summer and fall seasons, when ambient temperature is high.
C. botulinum has a minimum growth temperature of 15°C (60°F). Although it grows best at temperatures between 30°C (86°F) and 40°C (104°F).
Survival in the Environment: Anywhere where there has been raw sewage discharge and deaths of terrestrial and aquatic invertebrates and fish posses an increased risk of botulism. Maggots can also pose a risk because they are able to harbor the toxin in their bodies. In water,
C. botulinum requires a pH between 5.1 and 5.4 to grow.
Incubation Period: The shorter the incubation period, the more severe the disease and the higher the case fatality rate. Food-borne botulism usually takes 12 to 72 hours after ingestion of the toxin, depending on the dose. Wound botulism may take up 7 days.
