Fowl cholera is a contagious bacterial disease affecting various domestic and wild birds worldwide. It is caused by the bacterium Pasteurella multocida. The disease can lead to significant health issues and even death in poultry flocks, posing a substantial concern for bird owners.
Symptoms of Fowl Cholera
Fowl cholera presents in two main forms: acute and chronic. The acute form often manifests as sudden death, which can be the first indication of infection. Birds may also appear severely depressed, exhibit ruffled feathers, and lose their appetite. Respiratory signs like a mucous discharge from the mouth or nose and increased respiratory rate are common. Affected birds might also develop greenish, watery diarrhea and experience a bluish discoloration of the skin, wattles, and comb, known as cyanosis.
Birds that survive the acute phase may develop the chronic form. This form typically involves localized infections. Swelling of the wattles, sinuses, joints, or footpads is frequently observed, leading to lameness. In some cases, middle ear infection can result in neurological signs, such as a twisted neck (torticollis).
How Fowl Cholera Spreads
Fowl cholera primarily spreads through contact with infected birds, which shed the Pasteurella multocida bacteria through nasal and oral secretions. Direct bird-to-bird transmission occurs readily within a flock. Ingestion of contaminated feed or water is a common route.
Environmental contamination plays a significant role in disease spread. The bacteria can persist on various surfaces, including feed, water, equipment, and soil. Contaminated crates, feed bags, and even shoes can spread the organism between different areas or flocks. Chronically infected birds, even those appearing healthy, can act as carriers, continuously shedding the bacteria and posing a long-term risk to susceptible birds. Wild birds, rodents, and predators like cats or raccoons can also introduce the bacteria to a flock by carrying the pathogen or feeding on infected carcasses.
Managing an Outbreak
When fowl cholera is suspected or confirmed in a flock, contacting a veterinarian immediately is important for diagnosis and treatment. Laboratory testing can confirm the presence of Pasteurella multocida and help determine the specific strain. Antibiotics, such as sulfa drugs or tetracyclines, are often used to control the spread of the outbreak and reduce mortality rates.
While antibiotics can suppress the infection, they may not eliminate the bacteria entirely, especially in carrier birds. The bacteria can also develop resistance to certain antimicrobial treatments over time. In severe outbreak situations, culling sick birds may be necessary to prevent further transmission within the flock and protect the remaining healthy birds. This helps to contain the disease and minimize economic losses.
Prevention and Biosecurity
Preventing fowl cholera relies on robust biosecurity measures. Quarantining all new birds for several weeks before introducing them to the main flock is a foundational practice. This isolation period allows for observation and helps ensure new birds are not carrying the pathogen.
Maintaining strict sanitation practices is also important. Regular cleaning and disinfection of coops, feeders, and waterers help eliminate environmental contamination. The Pasteurella multocida bacterium is susceptible to ordinary disinfectants, sunlight, and drying. Pest control measures are needed to keep rodents and wild birds away from the flock and their feed sources, as these animals can be carriers. Vaccination is an additional preventive tool, particularly for larger or high-risk flocks. Both live attenuated vaccines and adjuvanted bacterins are available and can be discussed with a veterinarian.