Principle and Prevention of Wild Duck Influenza

Wild duck is a typical representative of waterfowl, which is the common name of mallard duck (mallard) in the northern hemisphere. Wild duck belongs to bird class, goose-shaped order, duck family; its number is very large, is the popular name of many kinds of wild ducks, there are more than ten species. Not afraid of hot and cold, can live normally at-25-40 ℃, so the suitable breeding area is very wide. Strong disease resistance, less disease occurrence, high survival rate, more conducive to intensive feeding.

Influenza is a very common disease in wild ducks. if it is not well prevented, it will bring huge losses to wild duck farmers, so what is wild duck influenza? How to prevent and cure it? Now I would like to introduce to you.

The principle of wild duck influenza:

Wild duck influenza, formerly known as true chicken plague, also known as European chicken plague, referred to as avian influenza, is a contagious syndrome of birds caused by influenza A virus.

The pathogen is avian influenza virus, which belongs to type An influenza virus belonging to Orthomyxoviridae and wave influenza virus. Influenza A virus can be divided into many different subtypes due to the different combinations of hemagglutinin and neuraminidase glycoproteins, and there is no cross immunity among the subtypes.

(epidemic characteristics) Influenza viruses can be divided into non-pathogenic, low pathogenicity and high pathogenicity. At present, waterfowl are mainly caused by highly pathogenic strains, which have strong pathogenicity and high morbidity and mortality. Influenza virus exists in poultry nasal secretions and feces, due to the protection of organic matter, the virus has a strong resistance.

(clinical features) the incubation period ranges from hours to days, with the longest being 21 days. Sick birds suddenly come straight to the point, with elevated body temperature, loss of appetite or abstinence, shrinking head, mental fatigue, withered feathers and lethargy. Some waterfowl have symptoms of spirit. Faeces are sparse, yellowish white or yellowish green. Most of the diseased bird's eye conjunctiva is congested, flushed or bleeding, and in severe cases, the nasal cavity also bleeds. Some have corneal opacity and blindness; some have large head and face and edema in the lower jaw, and the laying rate of laying ducks drops sharply after infection, or even stops laying. Even if the eggs are laid, the eggs become smaller, the egg weight is reduced, and some deformed eggs appear. Before death, most waterfowl beak and feet poof color cyanosis, some can see foot scale bleeding.

(autopsy features) the beak end of dead waterfowl is cyanotic, and some heads and faces are also cyanotic. Some waterfowl head and face swelling, head bleeding, showing jelly-like edema, severe jaw can also appear jelly edema, eye conjunctiva and nasal mucosa hyperemia, bleeding, edema. Some tracheal mucosa, whole body subcutaneous fat bleeding. The liver is enlarged with scattered hemorrhagic spots and necrotic foci. In the course of the disease, the texture of the liver hardens. The gallbladder dilated and enlarged. Splenomegaly, blood stasis, and scattered necrotic spots. Myocardial degeneration, necrosis, coronary fat and pericardial hemorrhage. There are bleeding spots under the mucous membrane of glandular stomach and musculogastric cuticular membrane, and some bleeding zones are formed at the junction of glandular stomach and esophagus. The mucous membrane of small intestine is often congested and bleeding, and some of the whole intestinal mucosa are diffuse hyperemia and bleeding. The pancreas was swollen, bleeding and necrotic. The kidney is enlarged and bleeding on the surface. The cerebral vessels of dead waterfowl with neurological symptoms were congested, and some brain tissues showed grayish yellow necrosis. Enlargement and bleeding of the supraluminal cyst can be seen in the chicks. Egg-laying waterfowl cloacal mucosa hyperemia, bleeding, edema; egg deformation, degeneration; follicular congestion, bleeding, some follicles are purple grape-shaped.

(diagnostic features) according to the clinical symptoms and pathological changes of diseased wild ducks, combined with the epidemic characteristics of acute onset, rapid spread, short course of disease and high mortality, a preliminary diagnosis can be made.

Prevention and control measures of wild duck influenza:

Strengthen quarantine and strictly prevent the introduction of highly pathogenic avian influenza virus.

Strengthen feeding and management, pay attention to environmental hygiene, improve body resistance, and avoid contact with wild waterfowl when grazing wild ducks.

For healthy wild ducks, inactivated vaccine against highly pathogenic avian influenza should be vaccinated. The first immunization was at the age of 7-10 days, with 0.5 ml of intramuscular injection, and repeated once 3 months later, 1 ml of intramuscular injection.