Diagnosis and Treatment of Newcastle Disease in Silkie Chickens

Newcastle disease is an acute septicemic infectious disease caused by Newcastle disease virus. It can occur in all four seasons and often causes devastating epidemics.

Epidemiological characteristics:

Peracute type: mostly occurs in the early stage of an epidemic. Onset is rapid, mortality is high, most symptoms do not appear, and death is sudden. Acute type: sick chickens are listless, with eyes closed and neck drawn in, and the comb and wattles are dark red or purple-black. Oral mucus hangs from the tip of the beak, and the birds shake their heads and swallow, making “gurgling” sounds and coughing sounds. Feed intake decreases, and droppings are thin and yellow-green or yellow-white. Some sick chickens show neurological symptoms. Subacute or chronic type: uncoordinated movements, twisted head and neck, circling or backing up, purposeless head nodding, and partial or complete paralysis. Sick chickens sometimes have diarrhea and become emaciated. This type mostly occurs in adult chickens in the later stage of an epidemic, and mortality is relatively low. In laying hens, the laying rate decreases, and soft-shelled eggs, discolored eggs, and deformed eggs increase.

Key points for diagnosis:

(1) A large amount of filthy mucus often accumulates in the larynx and trachea, and its mucosa is congested and hemorrhagic; the thymus is also congested and hemorrhagic.

(2) In laying hens, ovarian follicles may be deformed, yolk may become thin, and follicles rupture easily, forming yolk peritonitis.

(3) The proventriculus is swollen, with hemorrhage of the proventricular papillae and hemorrhage beneath the keratinous membrane of the gizzard.

(4) Intestinal lymphoid follicles are swollen, with jujube-pit-shaped hemorrhage or necrosis, often protruding above the mucosal surface, and the cloaca has scabbing, hemorrhage, or necrosis.

(5) The mucosa of the cecum and rectum shows striped hemorrhage, and the cecal tonsils are swollen, hemorrhagic, and necrotic.

Prevention and control measures:

(1) Regular vaccination is the fundamental measure for preventing this disease. In high-incidence areas and seasons with many diseases, inactivated vaccines are best used.

(2) Scientific medication for prevention: eliminate or reduce the occurrence of stress, and regularly use antibacterial drugs to prevent intestinal diseases.

Treatment methods:

Administer Newcastle disease strain II or strain VI or clone.30 vaccine at 3-5 times the dose in drinking water once. Anti-stress drugs can be added to the water, and drugs for treating Escherichia coli and Salmonella can be added to the feed to prevent concurrent infection. One week later, inject Newcastle disease inactivated vaccine intramuscularly once.