How to prevent and control avian influenza in Silkie chicken farming

(1) Pathogen: type A influenza virus.

(2) Epidemiological characteristics: Silkie chickens are susceptible, geese can also be infected and develop the disease, and ducks may be the main host of influenza virus. The mortality rate varies with different virus strains, and highly pathogenic strains have a high mortality rate. In some chicken farms, the mortality rate is 10%-40%. Most laying hen flocks only show a decline in egg production, with a mortality rate not exceeding 2%. Growing flocks have a higher mortality rate than laying hens.

(3) Symptoms and lesions: Sick chickens are depressed, have a high fever, and refuse feed. Sick chickens quickly fall into a state of lethargy, with swollen eyelids, hemorrhage and cyanosis of the comb and wattles, and edema often appearing on the head and neck. Purple hemorrhagic spots appear on the scales of the legs. Some show respiratory symptoms, coughing, sneezing, rales in the trachea, tearing, swelling of the paranasal sinuses, and diarrhea. Egg production declines by 15%-70%. Necropsy shows edema of the head, around the heels, and wattles, yellow gelatinous fluid under the skin, hemorrhagic spots in the pectoral muscles and fat, hemorrhage in the oral cavity, glandular stomach mucosa, under the keratin layer of the muscular stomach, and duodenum, hemorrhage and necrosis in the liver, spleen, and kidneys, hemorrhage in the nasal cavity, trachea, bronchial mucosa, and lungs, and mucus and blood in the larynx and trachea. Confirmation can be done using the agar gel diffusion test to check for avian influenza antibodies and virus isolation and identification. According to regulations, the confirmation of avian influenza can only be carried out by the provincial animal husbandry authorities.

(4) Prevention and control: At present, there is no truly specific treatment method. The use of antibacterial drugs can reduce the impact of concurrent or secondary infections with Mycoplasma and Escherichia coli and reduce losses; another report indicates that amantadine has a certain therapeutic effect. Once an outbreak occurs, strict blockade and control of the movement of chicken flocks should be implemented, and strict disinfection measures should be taken. Usually strengthen the sanitation management of chicken flocks, and do not introduce breeding eggs and Silkie chicks from epidemic areas.