1、 Overview of Pigeon Newcastle Disease

Newcastle disease is an acute, highly contagious, and lethal infectious disease in poultry caused by the Newcastle disease virus (NDV). NDV belongs to avian type I paramyxovirus (APMV-1), and when pigeons are infected with APMV-1, it is called pigeon Newcastle disease or pigeon plague. In clinical practice, the clinical symptoms of pigeon Newcastle disease are very similar to those of chicken Newcastle disease, mainly manifested as neurological symptoms such as turning the head and neck, paralysis, as well as digestive symptoms such as diarrhea and green manure.

Pigeon Newcastle disease was first discovered in Germany in 1974. In 1985, the disease was transmitted to Hong Kong, China. In the same year, Zhuhai Gongbei Customs detected the Newcastle disease virus in imported pigeons.

NDV is a single stranded negative stranded RNA virus that encodes six structural proteins (L, NP, P, HN, F, M). Among them, hemagglutinin neuraminidase (HN) protein can bind and dissociate with red blood cells (RBCs). Therefore, NDV agglutination of RBCs is an effective and simple means of diagnosing the disease.

2、 Current situation of pigeon Newcastle disease epidemic

Based on the characteristics of the virus genome; NDV strains are classified as Class I and Class II; Class I has only one genotype, mainly isolated from wild birds; Class II has 21 genotypes, among which NDV strains of genotype I, II, VI, and VII have all been isolated in pigeons, but the majority are genotype VI strains. Pigeons can be infected by all NDV strains, but are particularly susceptible to genotype VI strains, with the majority being VIb (see Table 1); Chicken NDV is highly pathogenic to pigeons, but pigeon NDV may not necessarily cause high pathogenicity to chickens.

Pigeon Newcastle disease can occur all year round, with a higher incidence in spring and autumn. The incidence rate is as high as 50%~100%, and the mortality is 20%~80%. But it's not that a large number of pigeons die quickly in a short period of time, but rather that small batches of them die of illness every day, and the epidemic period sometimes lasts for 1-2 months.

Pigeons of different breeds, age groups, and genders can all be infected. Roast squab and young pigeon pair  NDV is more susceptible, the symptoms after infection are more typical, and the incidence rate and mortality are higher. Adult pigeons have a certain resistance to NDV, and the incidence rate and mortality are low after infection, but it will cause a serious decline in production performance and virus transmission in the field.

The onset time is concentrated after 20 days of age, mainly manifested as respiratory and digestive symptoms, and drug treatment has no significant effect.

The main transmission routes are the respiratory and digestive tracts. Direct contact with infected pigeons or virus contaminated air, feed, water, utensils, and sports fields can all cause infection in healthy pigeons;; Egg laying can also spread viruses.

(Data source: Ye Youchao et al. [Epidemic and Prevention of Pigeon Newcastle Disease])

3、 The harm of pigeon Newcastle disease

According to the clinical manifestations of Newcastle disease, it can be divided into acute type, neurological type, diarrheal neurological type, and dyspnea type.

Acute disease pigeons only have abnormal feeding and do not show any other clinical symptoms, resulting in a large number of sudden deaths, which is more common in young pigeons in the early stages of the disease; The main clinical symptoms of neurological disease in pigeons are severe neurological symptoms, with a short course of illness from infection to the obvious stage, presenting symptoms such as head twisting, neck extension, foot paralysis, inability to stand, and drooping wings; In the early stage of diarrhea, white and watery stool is discharged, which then turns into grass green stool. The spirit is depressed, the feathers are loose and messy, the appetite is lost, and thirst increases; Some sick pigeons are accompanied by symptoms such as paroxysmal spasms, tremors, head tilting and neck twisting, and head tilting backwards, with a mortality rate of up to 50%.; Pigeons with difficulty breathing open their mouths to breathe, with secretions in their nostrils. A small amount of pigeons may have conjunctivitis or inflammation of the eyes.

The typical lesions of autopsy mainly include three locations:

One is extensive subcutaneous congestion and bruising, particularly evident in the neck, often presenting as redness& nbsp; Purple red and black red like nodular bleeding; Secondly, there are striped bleeding on the esophageal mucosa, obvious or diffuse bleeding points on the glandular gastric papilla, spotted or patchy bleeding at the junction of the glandular and muscular stomach, bleeding under the stratum corneum of the muscular stomach, and congestion of the glandular gastric mucosa;; The small intestine mucosa shows catarrhal inflammation, with congestion and bleeding of the intestinal mucosa, especially severe duodenal ulcers and bleeding, congestion of the cecal tonsils, and bleeding of the cloacal mucosa; The third is cerebral congestion, bleeding, and cerebral edema.

4、 Prevention and Control Plan for Pigeon Newcastle Disease

1、 We should adhere to the principle of "self breeding and self raising, prevention first", and self breed young pigeons to prevent the spread of infectious and parasitic diseases from other pigeon farms.

2、 If you need to purchase pigeons from other places, you should promptly take measures to prevent the spread of Newcastle disease after purchasing them. Thoroughly conduct quarantine and observation, and isolate for 3 weeks to confirm that there is no disease before entering the breeding site. However, it is best not to mix with the pigeon flock in the short term.

3、 Strengthen feeding management: Provide different levels of feed according to the nutritional needs of pigeons at different stages to enhance their resistance and prevent malnutrition.

4、 Ensure biological safety: pigeon coops, personnel, venues, and equipment should be regularly disinfected. Regularly kill rats and insects. It is strictly prohibited to feed other poultry (chickens, ducks, geese, etc.) in the pigeon house area to avoid cross infection.

5、 Strictly carry out immunization. Establish a reasonable immunization program and recommend receiving inactivated Newcastle disease vaccine twice a year; Immunization should be carried out in good conditions and favorable weather conditions for pigeons, with regular monitoring of their antibody levels and timely adjustment of immunization programs.

Roast squab are generally not vaccinated before they are marketed. Pigeon breeding immunity is divided into two categories: pigeon farms contaminated with Newcastle disease and pigeon farms without Newcastle disease contamination& nbsp;

Pigeon farms without Newcastle disease pollution: 20-25-day-old individuals should receive one dose of the twice attenuated vaccine through eye and nasal immunization; Immunization with inactivated vaccine once at 50-60 days of age; From now on, immunize with 3-5 fold attenuated vaccine every 6 months through drinking water, or immunize with inactivated vaccine every 12 months.

Newcastle disease contaminated pigeon farms: Individuals aged 15-25 days should receive 2-3 times the attenuated vaccine through eye and nose immunization once; Immunization with inactivated vaccine once at 45-55 days of age; From now on, immunize with 3-5 fold attenuated vaccine every 3 months through drinking water, and immunize with inactivated vaccine every 6 months.