Pigeon worker type paramitoid virus

Raising pigeons is the same as raising other poultry, raising a wide range of areas, the number of more, the epidemic is bound to increase. This disease is a highly contagious and septic infectious disease caused by pigeon type I parasite virus discovered in recent years. Commonly known as pigeon Newcastle disease, some are also called pigeon plague, sometimes ferocious in pigeons, sometimes sporadic. Suckling pigeons are likely to die in large numbers when they are infected with this disease, and young pigeons and their parents will also die. The incubation period of the disease is 1 ~ 10 days, usually 1 ~ 5 days. The appearance before the disease is completely normal. In mixed flocks, the virus can be transmitted to @ # @ 247 birds from different flocks of pigeons, causing an outbreak of the disease. Characterized by dysentery, tremor, unilateral or bilateral leg paralysis, chronic and late epidemic cases have symptoms of head twisting and neck tilting, the mortality rate is between 20.80%, and the general mortality rate can reach more than 50%. In late October 1997, 30,000 pairs of pigeons were raised in a pigeon farm in Zhejiang Province, of which 500 pairs of breeding pigeons first developed the disease. Only two months after interference treatment, the disease occurred in two young pigeon houses, from taking comprehensive prevention and control measures to controlling the disease for more than 4 months. more than 3000 pairs of parent pigeons, 4500 pairs of young pigeons and more than 5000 pairs of squab died successively. The death rate of parent pigeons is 13%, while the mortality rate of young pigeons (including elimination) is more than 50%, and the direct economic loss is nearly 1 million yuan, which shows that the disease does great harm to pigeon industry. When pigeons go out for training and flight competitions, pigeons of different groups are placed in the same vehicle or in the same room, which is easy to spread the disease.

1. Clinical symptoms

At the beginning, the sick pigeon was mentally tired, loose feathers, loss of appetite, increased thirst, tremor, watery diarrhea, standing still, but still able to escape capture. With the development of the disease, sick pigeons close their eyes and shrink their necks, refuse to move, lose their appetite, and tremor all over the body. They often swallow saliva, and dilute feces change from watery to mostly green-white or yellowish-white. In particular, the feathers near the cloaca and the rear abdomen are soiled by feces. Most sick pigeons have neurological symptoms, and later appear leg paralysis, sick pigeons can not stand, often crouching or lying on the side, drive, can only use its lying side to the ground, the upper side of the foot to move the body. Such as paroxysmal spasm, pigeon body muscle tremor, crooked neck or stiff neck, see food want to eat but always peck wrong and can not eat mouth, want to walk forward can not, can only make a circle, some head backward, some can see unilateral leg or wing paralysis, some walk and fall, often with head shaking, neck crooked, wing drooping, soft feet, circle, ataxia-based neurological symptoms. A few sick pigeons have ophthalmitis, conjunctivitis and nasal secretions. Finally pull green thin or mushy feces and die of failure. The course of the disease is 3-7 days, but some are as long as 10 days. The sick pigeon with a long course of disease weighs very little and has no luster in its feathers. The pigeon body shows extreme exhaustion. At this time, the number of cases with neurological symptoms increased, but the increase in some fields was not obvious.

The disease sometimes presents a sudden outbreak, resulting in a large number of pigeons, rapid death, and sometimes slow occurrence, so that pigeons continue to die sporadically. If other diseases occur together, the loss of death will increase.

2. brake examination of pathological changes

Its pathological changes are roughly the same as those of Newcastle disease. The eyes of most pigeons are sunken in appearance, and 30-40% of the diseased pigeons have conjunctival inflammation, hyperemia, bleeding and secretions. The shins and feet are dry and wrinkled and the feathers are seriously contaminated. During the autopsy, the skin is difficult to peel off, and the muscle can be seen dry and slightly flushed after dissection. The chest muscles are plump but also extremely thin, with extensive subcutaneous ecchymosis, especially in the neck, with red, purplish red and other colors, which is an inherent characteristic lesion. Edema of coronary sulcus, meninges and cerebral parenchyma with small hemorrhage. In some pigeons, the balloon membrane was turbid and the glandular gastric papilla was obviously bleeding, some formed a bleeding zone at the junction of the glandular stomach and the myogastric, some had macular congestion or bleeding under the cuticular membrane, and occasionally the glandular bursa showed dark red hyperemia. The pancreas has hyperemia spots and marbling with uneven color. There is bleeding from the duodenum to the rectal membrane; hepatomegaly with bleeding spots and hemorrhagic spots; splenomegaly with congestion spots; pale and enlarged kidneys; lungs with varying degrees of gray liver degeneration with partial necrosis on the edge; and hemorrhagic spots on the skull. In some cases, the larynx and trachea are congested or bleeding, and some of them are filled with fluid or cheese.

3. Prevention and control

To prevent this disease, we should strengthen the feeding and management of pigeons, feed with nutritious feed, ensure the requirement of nutrients and vitamins, and improve the hygiene of pigeon houses and reduce stress factors, so as to improve the physique of pigeons and enhance the ability of disease resistance. At the same time, it is necessary to establish and improve the veterinary epidemic prevention system in the field and conscientiously implement it, formulate feasible immunization procedures, and carry out epidemic surveillance and vaccination regularly. Vaccination is a key measure to effectively prevent the occurrence of this disease. The immune effect of upper respiratory tract inoculation was better than that of pterygoid membrane or muscle inoculation. The prevention and control methods that can be selected according to different conditions are as follows:

(l) the most effective vaccine is pigeon type I virus inactivated vaccine. When the vaccine is injected subcutaneously in the neck, there is no strong reaction, and it has a good immunity after one vaccination, which is very safe. The antibody of pigeon body can be raised from 0 to 25 level of micromethod 7 days after injection. If the same inoculation was made at this time, the antibody titer increased by 2 more after 7 days, that is, the level reached 27. After that, they were vaccinated once every 6 months or so. Generally speaking, each person is 0. 5% when inoculated. 5 ml (one needle is required for emergency prevention). Under normal circumstances, the pigeons reserved for breeding should be vaccinated once at the age of 1 month, and once more at the age of 4 months before the birth. The old pigeon can be vaccinated once in 6 ~ 12 months.

(2) when there is an epidemic, in addition to the rapid supplementary vaccination of breeding pigeons that have not been injected or have been injected for half a year, it is also necessary to strengthen the epidemic prevention of young pigeons. Suckling pigeons over 5 days old can be vaccinated with 4-8 doses of Newcastle disease W vaccine (each one). If you consider keeping it for breeding or a serious threat to the epidemic, you can also subcutaneously inactivate pigeon worker type parvovirus vaccine 0. 2 ~ 0. 5 ml (each).

(3) for the pigeon farms where the epidemic has occurred, emergency vaccination should be carried out as soon as possible, and each pigeon should be injected with 2 feathers of pigeon worker type parvovirus inactivated vaccine, and even consider injecting 8 feathers of Newcastle disease IV vaccine at the same time, so as to quickly control the epidemic and reduce the loss. Or it is more convenient to inject bivalent vaccine produced by the Department of Animal Medicine of South China Agricultural University. (4) for the outbreak pigeon farm, in practice, we use the inactivated tissue vaccine made of typical virus tissue (which is developed through certain procedures, such as kidney, spleen, brain, liver and other organs of infected pigeons) for emergency vaccination. it is the best way to quickly control the epidemic of the disease; at the same time, it has a good effect on the emergency vaccination of pigeon flocks in suspicious farms and the emergency vaccination of early diseased pigeons.

(5) as for pigeon Newcastle disease attenuated vaccine, although it can be used, it is best to be cautious in the field without this history of disease, in case its virulence is enhanced in the continuous circulation of pigeon body. The attenuated vaccine of pigeon Newcastle disease can be injected intramuscularly with multiple doses of n-line during the epidemic period. if the W-line vaccine is used, it may cause a greater reaction to the pigeon flock in the epidemic period or the effect may not be significant. Therefore, the effectiveness of the use of this kind of vaccine depends to a large extent on the appropriateness of the selected vaccine.

At the same time, comprehensive epidemic prevention measures should be taken to strengthen the isolation, disinfection and hygiene work in peacetime and epidemic areas, which is very important, especially when there is an epidemic disease, it should be thoroughly disinfected to prevent the invasion or spread of pathogens. Specifically, after the diagnosis, sick pigeons and healthy pigeons should be quarantined immediately, all dead pigeons should be buried or destroyed, and pigeon houses and venues should be strictly sterilized.