Fowl cholera, also known as avian cholera, avian pasteurellosis, or avian hemorrhagic septicemia, is a bacterial disease that affects various bird species, including poultry, turkeys, ducks, geese, raptors, and canaries. It is caused by the bacterium Pasteurella multocida. It is a zoonosis that can be transmitted from animals to humans. Adult birds and old chickens are more susceptible to the disease, which is more common in cockerels than hens.
Fowl Cholera Disease Management in Chicken
Occurrence of Fowl Cholera Disease
Fowl cholera outbreaks typically occur in cold and wet weather, particularly in late summer, fall, and winter. The disease is often introduced to a flock through the presence of rodents in breeding houses that spread the bacterium from carcasses of dead birds that may have been improperly disposed of, including those from neighboring backyards.
Once introduced, the disease can persist in the flock until culling, and chronic carriers may cause re-emergence of the disease in susceptible birds. In wild birds, wetlands are the most common sites associated with the disease, acting as short-term reservoirs that record large amounts of the bacterium in the soil and water during outbreaks.
The disease can present in two forms, acute and chronic, with acute infections resulting in death within 6-12 hours of contracting the bacterium. Waterfowl are most commonly affected by fowl cholera due to their association with dense aggregations. Still, scavengers and other water birds can also be affected during large, multi-species outbreaks.
Disease cycle of Fowl Cholera
The disease cycle of fowl cholera involves the introduction of the Pasteurella multocida bacterium to a susceptible bird population through inhalation, ingestion, or contact with contaminated materials. The bacteria then colonize the respiratory or gastrointestinal tract, causing clinical signs such as respiratory distress, nasal discharge, and diarrhea. The bacteria may also invade the bloodstream, leading to sepsis and death.
Infected birds shed the bacteria through nasal exudate, feces, and contaminated materials, which can infect other susceptible birds or contaminate the environment. Carriers, including scavengers, predators, and chronically infected birds, can perpetuate the infection cycle by shedding the bacteria into the environment. Contaminated water and soil can also harbor the bacteria for long periods, leading to the re-infection of susceptible birds.
Symptoms of Fowl Cholera Disease
- Symptoms of fowl cholera can include dejection, ruffled feathers, loss of appetite, diarrhea, coughing, nasal, ocular, and oral discharge, swollen and cyanotic wattles and face, sudden death, swollen joints, and lameness.
- In chronic cases, localized infections are more common, often occurring in the respiratory tract, sinuses, pneumatics bones, hock joints, sternal bursa, foot pads, peritoneal cavity, and oviducts.
- In acute cases, typical post-mortem lesions include petechiae in the epicardial fatty tissue, necrotic foci on the liver, and general hyperemia.
Impact of Fowl Cholera on Chicken
- High mortality rates early stages of the disease
- Chronic infection can lead to continued mortality and decreased production.
- A high percentage of the flock can become carriers while appearing normal.
- Losses usually occur in birds over 16 weeks of age.
- Economic losses due to decreased production and increased cost of treatment
- The potential spread of the disease to other flocks or neighboring farms
- Increased risk of zoonotic transmission to humans handling infected birds.