Diagnosis and treatment of ⅰ paramyxovirus infection in American King Pigeon

In recent years, with the change of rural economic structure, American white-feathered king pigeon farming has gradually developed in our city. From January to May 2002, some royal pigeon farms in Youxian District, Fucheng District, Anxian County, Santai County and Shantong County in Mianyang City broke out successively with diseases characterized by green water samples, sparse feces, no food, short course of disease and high mortality, which caused serious economic losses to farmers. Pigeon Ⅰ paramyxovirus infection was diagnosed by on-site comprehensive diagnosis (epidemiology, symptoms, autopsy) and laboratory examination. The infected pigeon farms and local pigeon flocks were immunized with tissue inactivated vaccine made from liver, spleen and brain of sick and dead pigeons, and satisfactory results were obtained in controlling the epidemic situation. Over the past year, the local epidemic of the disease has been basically controlled, and the relevant situation is now reported as follows.

I. epidemic situation and symptoms

In late January 2002, there were about 3500 pigeons in the American white feather king pigeon farm in Weicheng Town, Youxian District, Mianyang City and Jiepai Town, an County, including more than 1400 squab pigeons. The disease occurs ferociously and spreads rapidly. it generally spreads throughout the population in about 7 to 10 days, and the incidence rate is as high as 60% and 80%. Diseased pigeons are lethargic, loose feathers, unwilling to exercise; do not eat, but drink more water, pull green water-like sparse feces; tremor and instability occur in the later stage, and a small number of sick pigeons (mostly adult pigeons) appear neurological symptoms such as head twisting, torticollis, movement and flying disorders; the course of disease is mostly 1 to 5 days, and a few sick pigeons with neurological symptoms can be extended to more than 10 days, and the mortality rate of adult pigeons ranges from 30% to 80%. After the onset of the disease, the condition of the squab was acute and the course of the disease was short. most of the squab at the age of 7 to 10 days died suddenly without obvious symptoms, and there were few more than 1400 squab left, with a mortality rate of nearly 100%.

It is understood that the above two pigeon farms have not carried out any immunization, after the disease has been treated with norfloxacin, gentamicin, oxytetracycline.

By May 2002, more than a dozen royal pigeon farms in Fucheng District, Santai County and Zitong County, Mianyang City, also had the above epidemic disease one after another.

2. Autopsy

Autopsies were performed on more than 30 dead pigeons. The consistent pathological changes were as follows: the appearance of the body was slightly dehydrated (sunken eyeball, shin dry), the feathers around the anus were often contaminated by green dung, and there was mucus in the mouth; there were obvious patchy purplish red and black blood stasis bleeding areas under the skin of the neck; blood spots were often seen on the skull surface of the head; sour gas and liquid were accumulated in most crops. The spleen is slightly enlarged with obvious blood stasis and bleeding spots; the pancreas has uneven hyperemia and bleeding spots; the myogastric cuticular membrane is easy to peel off, and there is often speckled bleeding under the cuticular membrane; intestinal (especially duodenum, rectum) and cloacal mucosa seriously bleed. Some diseased pigeons can see throat, trachea blood stasis, bleeding, a small amount of epicardial bleeding points, a few sick pigeons can see glandular gastric mucosal congestion and bleeding.

No obvious pathological changes were found in liver, kidney, lung, chest, abdominal cavity and so on.

III. Laboratory inspection

1. Bacteriological examination: the liver, spleen and heart blood smears of sick and dead pigeons were smeared and no bacteria were found under microscope after Gram staining, and the liver, spleen and brain of sick and dead pigeons were taken by aseptic operation and inoculated in common Agar plate and McConkey medium and cultured for 24 hours with 37 ℃, there was no colony growth.

two。 Newcastle disease hemagglutination inhibition test: blood was collected from the hearts of 16 diseased pigeons, and the serum was separated. The titer of Newcastle disease hemagglutination inhibition antibody was determined by p-micromethod. The results showed that there were different hemagglutination inhibition antibodies in the range of 210g2~810g2. Among them, 2 were 81% 2, 5 were 71% 2, 2 were 61% 2, 1 was 51% 2, 2 was 410g2, 3 were 21% 2, and 1 was not detected antibody.

IV. Prevention and control measures

1. The diseased pigeon farm (pigeon house, pigeon body surface, utensils, etc.) was completely disinfected with Baidu, and the dead pigeon was deeply buried after sprinkling disinfectant. Drinking water with Baiyanxiao was used to control the secondary infection of bacteria, and multi-dimensional electrolysis was added to the drinking water to supplement the water loss caused by diarrhea and regulate the balance of electrolytes in the body.

two。 The brain, liver and spleen of dead pigeons with typical pathological changes were added with normal saline in proportion, homogenized and filtered by high-speed tissue crusher, inactivated with formaldehyde, and qualified by aseptic test and safety test. This time, a total of about 40,000 milliliters of tissue inactivated vaccine were produced, which were used for emergency immunization and healthy pigeon farm vaccination on newly infected pigeon farms. Suckling pigeons and adult pigeons over 10 days old, each pigeon was injected 1 ml subcutaneously or intramuscularly, repeated a week later, and enhanced immunization every six months thereafter. At the same time of injecting tissue inactivated vaccine, Newcastle disease clone 30 or N79 was immunized with regular drinking water. The sick pigeon farm generally controls the epidemic situation in about half a month after emergency vaccination, and basically returns to normal in about a month, thus greatly reducing the loss of the disease farm. Healthy pigeon farms are immunized according to the above methods, and the preventive effect is also very good. For more than a year, the local epidemic of the disease has been basically controlled.

V. discussion

1. Diseases characterized by green, sparse feces, no food, quick death and high mortality occurred in some king pigeon farms in Mianyang City from January to May 2002. through epidemiology, symptoms, autopsy and laboratory test results, pigeon Ⅰ paramyxovirus infection was diagnosed.

two。 Once Ⅰ paramyxovirus infection occurs in pigeon farms, it is an effective way to control the disease by using tissue inactivated vaccine made from local dead pigeons with typical pathological changes, together with ND clone 30 or N79 live vaccine, emergency immunization to pigeon flocks that have just occurred the disease and the surrounding threatened areas.

3. The reliable way to prevent the occurrence of this disease is vaccination. It is suggested that the use of pigeon Ⅰ paramyxovirus oil emulsion inactivated vaccine and injection of Newcastle disease Ⅳ strain (such as N79, clone 30) can have a better preventive effect.