Common poultry diseases
Newcastle. Newcastle disease is a zoonotic viral disease affecting all types of birds. Humans will typically present with a mild conjunctivitis. Chickens' clinical signs include a raspy chirp in chicks, as well as watery discharge from nostrils, dyspnea, swelling of the face, and limb paralysis. When the virus has affected the central nervous system, the chicken will present with a twisting of the neck. Adults will also show decreased food and water consumption, and decreased egg production.
Since it is a viral disease, treatment involves mostly supportive care. Antibiotics can prevent secondary bacterial infections. Chicks will also benefit by raising the brooding temperature by 5 F. Since the virus is transmitted by aerosol and contaminated sources, good sanitation and biosecurity program, and vaccination can help with preventing outbreaks.
Fowl pox. The virus that causes fowl pox can affect many species of birds. The virus is transmitted by mosquitos. There are two forms of the disease, and birds can be affected by both at the same time. Clinical signs of the dry form are wart or pox-like lesions on areas without feathers such as the legs, comb, and head. These will scab over and heal in about two weeks. The lesions heal in about two weeks. Chicks may also be affected and have poor growth and appear unkempt. Hens may show a decrease in egg production.
With the wet form, the lesions form in the mouth, trachea, larynx and pharynx. The lesions can cause obstruction of the respiratory tracts. The disease is rather slow to spread, so a vaccination protocol can be established to prevent further outbreaks. A good mosquito eradication program should be implemented, as well. With the disease being viral, there is no other treatment besides supportive care.
Infectious bronchitis. This extremely contagious viral disease affects all ages; however, the severity of the disease will depend on the age, presence of concurrent illnesses, environmental housing factors, and overall health of the bird. Typically, with all birds, inappetence and decrease in water consumption will occur, as well as dyspnea. In layers, egg production will decrease. Discharge from nostrils and eyes will also be present.
The virus, which is airborne, as well as from contaminated fomites, can also be transmitted to the egg, which inevitably will not hatch. Antibiotics may be administered to prevent secondary bacterial infections and raising the brooding temperature by 5 F can help decrease losses. There is a vaccine available, and establishing a good biosecurity program can help prevent outbreaks.
Avian influenza. AI can be classified as either mild or highly pathogenic. Clinical signs of the mild form include lethargy, poor appetite, respiratory issues, and diarrhea. The highly pathogenic form, however, causes severe dyspnea, facial swelling, cyanosis, and discoloration of the legs and combs. The virus can be spread easily from other infected birds, contaminated fomites, and insects. It can also thrive in the environment for a significant period of time. Administration of antibiotics to prevent secondary bacterial infections, along with supportive care, can reduce mortalities. Birds that recover can continue to spread the virus. There is a vaccine available. but must be administered with a special permit. Destruction of the entire exposed flock is recommended to prevent further spread, and any suspected case must be reported to state authorities.
1. Animal Behavior and Restraint: Poultry. https://www.cfsph.iastate.edu/Emergency-Response/Just-in-Time/08-Animal-Behavior-Restraint-Poultry-HANDOUT.pdf
2. Serling, J. Large animal medicine and nursing for veterinary technicians. 2021. Minneapolis, MN: Bluedoor.
