Avian influenza is an acute infectious disease of poultry caused by the avian influenza virus, some of which are asymptomatic cryptic infections, some are respiratory infections with low lethality, and some are acute hemorrhagic infections with high lethality.

This article introduces the main symptoms of avian influenza and prevention methods for reference.

First, what is the pathogen of avian influenza

The pathogen of this disease is avian influenza virus, which is a member of the influenza virus genus of Orthomyxoviridae. According to its antigenicity, influenza viruses can be divided into three types: a, b and c. The b and c types can only cause disease in humans, and the a type can cause disease in humans, pigs, horses and poultry.

The avian influenza viruses belong to the influenza a virus. They are divided into subtypes because they contain two antigenic substances, hemagglutinin (ha) and neuraminidase (na), which are antigenically different from each other on their capsule membrane fibrils.

During outbreaks of the disease in poultry, the virus can often be found in secretions and feces contaminated sinks or in the water of lakes or ponds where waterfowl are kept, but it cannot survive for long periods of time.

Second, the main symptoms of avian influenza

The incubation period of the disease can be from a few hours to a few days. Its clinical performance is mainly due to the subtype of the infected virus and present different symptoms.

1. The most acute type: caused by a highly pathogenic strain of the virus, often with no obvious symptoms and sudden death.

2, acute type: is the type of respiratory symptoms of the main symptoms, this type of chicken incubation period is shorter, usually 4-5 days. Often by the medium pathogenicity. It is a common type of avian influenza that occurs at present.

3. Chronic type: this type is caused by a weak pathogenic strain, with mild transient respiratory symptoms. Usually ducks show this type of disease. Duck flu alone has a low or no mortality rate, but it is often an important cause of death in bacterial secondary infections.

Lesions caused by highly pathogenic viruses are characterized by marked changes in the crown and drooping of the flesh, from blisters to severe swelling, cyanosis, bruising, and obvious necrosis, often accompanied by periorbital edema.

Sometimes the toes swell and turn purple. There are small hemorrhages on all plasma and mucosal surfaces, especially in the mucosa of the myogastric-glandular junction. Along the long axis of the pancreas there are often yellowish spots and dark red areas.

In some cases, necrotic foci are often seen on organs such as the liver, spleen, kidneys, and lungs. Some can cause severe lymphoid necrosis.

The prevention and treatment of avian influenza

Mainly by strengthening preventive measures. When the disease occurs, we must strictly implement the blockade, isolation, disinfection, burning of sick chickens and other comprehensive prevention and control measures. Once the disease occurs, the following measures must be taken:

(1) Immediately after diagnosis, the implementation of emergency measures, blockade and isolation of the infected area.

(2) Immediately formulate strict safety and epidemic prevention measures, strictly isolate the primary infected area and the surrounding poultry farms, and closely monitor the poultry farms assigned to the control area.

(3) Cull highly dangerous sick flocks and potentially dangerous flocks without any symptoms.

(4) Remove culled poultry, poultry products, waste debris, manure, feed, and equipment, then thoroughly clean and disinfect the entire farm.

(5) All premises where sick birds have been kept are fully cleaned and disinfected, and left vacant for more than 30 days before being allowed to resume production, and the poultry are to be kept under close surveillance thereafter.

(6) serological examination of flocks outside the infected area and a variety of wildfowl, the positive are culled, and new flocks into the field regularly do serological examination.

In prevention, should minimize and avoid wild birds and poultry, feed and water contact, to prevent wild birds into the poultry field, poultry house and feed storage room, pay attention to keep the water source clean and sanitary.