Newcastle disease in chickens or pseudo-snakes is a serious disease of birds of all ages, breeds and species that is prevalent throughout the world. Every year, this disease takes the lives of thousands of poultry, causing irreparable damage to the farm. Moreover, the virus is transmitted to humans. How to define it and how to fight, this article will tell.
The Newcastle virus (ND) according to the World Health Organization according to the danger and spread is equated to the highly pathogenic avian influenza - HPAI. Although the HPAI stamp is rarely seen, Newcastle outbreaks occur annually in many small bird farms in Africa, Asia and South America. Today, in highly developed economic countries, vaccination against the disease is mandatory.
Newcastle disease causes RNA-containing virus, which is referred to as virion. Its shape can be both rod-shaped and spherical with small processes. All his danger lies in the fact that he contains ribonucleoprotein, as well as enzymes and lipids, which help him quickly develop immunity.
In domestic chickens, the virus spreads mainly in embryos (10-12 days), but both chickens and adults are sick. Unlike ducks and geese, domestic hens also get sick, and are virus carriers at the same time. The disease is transmitted through wild birds, already infected domestic, from a person, as well as through inventory. Getting on the mucous membrane, the virus penetrates into the respiratory system and in the digestive tract.
For the first time a large outbreak of pseudo-pills was recorded in England in 1926. During World War II, illness arose in the USSR. At the same time, Soviet scientists came up with and developed a vaccine. For all the years of its existence, Newcastle disease has caused great economic damage to foreign and domestic poultry farms. Everything is due to the fact that 80-90% of diseased chickens die.
Symptoms of manifestation
Despite the fact that the incubation period of the virus lasts from 7 to 12 days, the disease itself is acute and rapid. In some cases, the bird dies within a few hours without any obvious symptoms. The main signs of Newcastle is a sharp decrease in the activity and appetite of the bird, an increase in body temperature to 44 degrees. Young chickens manifest damage to the respiratory and nervous system.
So, the symptoms of Newcastle disease:
- decreased appetite;
- depression, immobility;
- conjunctivitis and blurred eyes;
- the appearance of mucous discharge from the nose and mouth, coughing, coughing;
- damage to the nervous system - poor coordination of movement, paralysis of the neck or legs, epistotonus.
In the acute course of the disease, the bird dies within 3 days.
Chronic virus course
Although chickens have a chronic form of Newcastle disease, which is quite rare, in some domestic breeds with strong immunity, it can still occur. In this case, the hens are noted:
- cramping of the limbs;
- head reel;
- twitching neck;
- loss of appetite;
- rapid exhaustion;
- excitability of the nervous system.
Mesogenic strains of the virus cause such a disease. With proper treatment, chickens rarely die in these cases - from 15 to 30% of cases.
It is important to note that, despite the already long existence of the Newcastle virus, special therapy has not yet been developed. As a preventive measure, a general complex of sanitary and veterinary norms is used. Vaccination of chickens is required. At the same time, immunity occurs after 96 hours of grafting, as well as after the bird recovers and remains alive. Although this rarely happens, as in large farms of sick individuals, as well as at the first suspicions of the Newcastle virus, the chickens are killed.
It is important to note that the virus of the disease does not survive under the action of ultraviolet rays, therefore special lamps are installed on many farms as preventive measures. He also dies during the minute treatment with boiling water. Of the chemicals that are detrimental to Newcastle, are formaldehyde, phenol, beta-propiolactone, ethyleneimine, and alcohol.