Prevention and treatment of duck viral hepatitis

Duck viral hepatitis is a rapid and highly fatal infectious disease caused by duck hepatitis virus in ducklings. It is characterized by hepatomegaly, bleeding spots and neurological symptoms. In the new epidemic area, the mortality rate of the disease is very high, which can reach more than 90%. Let's take a look at the prevention and treatment of duck viral hepatitis.

Etiology of duck viral hepatitis

Duck viral hepatitis mainly occurs in 4-20-day-old ducklings, adult ducks have resistance, chickens and geese can not develop naturally. Diseased ducks and infected ducks are the main sources of infection, mainly through digestive tract and respiratory tract infection. Poor feeding and management, lack of vitamins and minerals, damp and crowded duck houses can promote the occurrence of the disease. The disease occurs in the season when ducklings are hatched. Once it occurs, it spreads quickly among ducklings, and the incidence rate can reach 100%.

Symptoms of duck viral hepatitis

The main results are as follows: 1. The incubation period of duck hepatitis is 1-4 days, with a sudden onset and a short course of disease. At the beginning of the disease, the spirit is dispirited, does not eat, the movement is dull, shrinks the neck, the wing is drooping, the eye is half-closed in a coma, and some appear diarrhea.

2. Duck hepatitis diseased ducks show neurological symptoms, restlessness, dyskinesia, body leaning to one side, foot spasms and death a few hours later. Before death, the head is bent backwards and the corner bow is stretched backwards. The mortality rate of duck hepatitis varies according to age. Ducklings within 1 week of age can be as high as 95% of ducklings less than 50% of ducklings aged less than 50% of those aged 4 or 5 weeks.

3. The characteristic lesions can be seen in the liver. The liver is enlarged, yellow-red or spotted, with bleeding spots and spots on the surface, and the gallbladder is enlarged and full of bile. The spleen is sometimes enlarged and looks like the flower spot of the liver. Most kidneys are congested and swollen. The heart muscle is cooked. Some cases of duck hepatitis have pericarditis, yellowish exudate and cellulose flocs in the air bag.

Prevention and treatment of duck viral hepatitis

1. Comprehensive measures: strict isolation and feeding of ducklings, especially those under 5 weeks old, should be provided with appropriate amount of vitamins and minerals, and drinking water from open-air pools inhabited by wild waterfowl is strictly prohibited. Hatching, brooding, breeding and fattening should be strictly divided, and feed tubes and appliances should be cleaned and disinfected regularly. At the beginning of the epidemic or after the hatchery is contaminated, the ducklings that come out of their shells should be immediately injected with high immune serum (or yolk) or the serum of convalescent ducks, each 0.3 × 0.5 ml, which can prevent infection or reduce death.

2. Preventive vaccination: intramuscular injection of chicken embryo attenuated vaccine into breeder ducks 2-4 weeks before eggs collection can protect ducklings hatched from infection. The specific method is to inject 1 ml vaccine into breast muscle of female ducklings at intervals of 2 weeks. Ducklings can also be inoculated with intramuscular injection, intradermal prickles or aerosol spray, which can effectively prevent the disease.

① introduced seedlings from healthy chickens and strictly carried out the disinfection system.

② was immunized with duck viral hepatitis I attenuated vaccine. Half a month before laying, adult ducks were injected intramuscularly with 1 / 2 and 2 / 2 / adult ducks in the middle of egg production. One duckling was injected subcutaneously at 1 or 7 days after coming out of its shell. In the epidemic area, chicks can also be injected subcutaneously with DVH-1 hyperimmune yolk fluid or hyperimmune serum at the age of 1-2 days for passive immunization.

Once the disease broke out in ③, the diseased ducks were immediately isolated and thoroughly disinfected in the duck house or water area. The infected ducklings were treated with standard DVH-1 high immune yolk antibody injection, 1-1.5 per duck, and attention should be paid to the control of secondary infection.

For the diseased ducks which are poorly controlled by standard DVH-1 attenuated vaccine or antibody, under the premise of excluding the poor quality of the vaccine and antibody and co-infection, ④ should isolate and identify the virus, explore the infection of DVH- type II, type III and DVH- 1 variant strain, and try to use local strains to prepare vaccines and antibodies for prevention and treatment.