Newcastle disease, commonly known as chicken plague, is also known as Asian chicken plague and atypical chicken plague. The disease is caused by The Newcastle disease virus and is an acute febrile, septic infectious disease. Chickens, turkeys, beaded chickens, quail, and pheasants are susceptible to the disease, and chickens are the most susceptible, but in recent years, the incidence of quail has shown a higher trend, and the route of infection is mainly the respiratory tract and digestive tract.
Popular features. Newcastle disease in quail is caused by the Newcastle disease virus, which causes sepsis after its invasion of the body and has a high mortality rate. The disease can occur throughout the year, but it is more common in late autumn, winter and early spring. The virus is mainly present in the saliva, feces, etc. of diseased quail, and infects healthy quail through feed, drinking water and utensils. Sick quails can also transmit the virus through the air when they cough or sneeze. Young quails aged 40 to 70 days are more common, and the incidence is lower at age of 7 months or older. Mortality is about 50% at the time of onset before egg laying and 10% at post-egg laying, but the course of the disease is longer and the egg production is significantly reduced.
Clinical symptoms. Quail Newcastle disease can be divided into three types: the most acute, acute and chronic.
1. The most acute type. The onset is rapid and sudden, and the quail has almost no abnormal clinical symptoms and dies quickly, but the mortality rate is not very high.
2. Acute type. At the beginning of the disease, the quail has an increased body temperature, lack of energy, decreased appetite or waste, but likes to drink. With the development of the disease, the clinical symptoms increase and are obvious, there is a liquid content or gas accumulated in the mouth, and a large amount of mucus flows out of the mouth when it is reversed, and the mucus is sour and smelly, and it is dark gray. Sick quails have loose feathers, droopy wings and tails, reluctance to move, eyes half or fully closed, isolated, shrunken necks, crown and fleshy hair are purple; Difficulty breathing, often making stridor; diarrhea is severe, pulling yellow-white or yellow-green stool, sometimes containing blood in the stool; The development of a long course of the disease is a nervous symptom such as head trembling, forward extension, unsteadiness in standing or hemiplegia, leg paralysis; Egg production by egg-laying quails has decreased, and soft-shelled and white-shelled eggs have increased. Generally 2 to 3 days of death, the case fatality rate is high.
3. Chronic type. More common in adult quail in the late epidemic, sporadic, low mortality, mainly neurological symptoms, showing excitement, paralysis and spasm, motor disorders, unstable gait, head and neck skewed, sometimes convulsive, less walking; The wings droop, emaciated, sometimes diarrhea, and finally death.
In recent years, the epidemic symptoms of quail Newcastle disease have shown atypical symptoms, showing low energy, and the amount of food intake and egg production rate have decreased significantly, and there have been sporadic deaths. The colour of the stool is light green, sparse, and has mild respiratory symptoms, especially at night. Some neurological symptoms can appear in chronic cases.
Autopsy changes. Its lesions are transparent secretions in the larynx and trachea, congestion of the tracheal ring, and congestion of the lungs; Bleeding from glandular gastric papilla, squeezing with purulent discharge, severe ulcer formation; Bleeding from the subkeratocosal mucosa of the gastrointestinal tract; Punctate bleeding of the mucosa of the duodenum, streaked bleeding in the rectum, and large bleeding points at the tip of the needle in the fat of the coronary heart; The kidneys are bruised and enlarged.
The longer the course of the disease, the more pathological changes there are. The acute type basically has the above changes. The most acute type of cadaver has mild changes, with bleeding spots only on the spoon surface of the sternum and epicardial membrane or no change at all.
Prevention and control measures. Prevention: (1) Strengthen breeding management, strictly prohibit the polyculture of other poultry in quail houses. Feed should be appropriately increased in a variety of vitamins, fishmeal, trace elements and other nutrients, can also be added to drinking water multivitamins to improve the resistance of quail. Reduces stress response. Keep the quail house and sports field clean and hygienic, and insist on regular disinfection. Eliminate the quail that have become ill and weak, and do a good job of harmless treatment. (2) Immunization. Develop immunization procedures according to the actual situation. 5 to 7 days old, can be used chicken Newcastle disease II system weak vaccine or Newcastle disease clone 30, nose drops and eye drops for vaccination. Drinking water immunization is performed at 28 to 35 days of age and 60 to 70 days of age, respectively. Before drinking water immunization, the water supply is stopped, causing the quail to feel thirsty, and the next morning the vaccine water is put in so that all the quail can drink water and drink within 2 hours.
Treatment: At present, there is no specific drug treatment for this disease, and quails with serious diseases should be eliminated and treated harmlessly. (1) Isolate the sick quail. Thoroughly disinfect the environment, feeding troughs and utensils in the house with 100 poisons. (2) Intramuscular injection of Newcastle disease yolk antibodies for the treatment of diseased quails, emergency vaccination of other quails, conditional feedlots, can be combined with leukocyte mediatins, the effect is better. (3) Strengthen breeding management. Give the whole quail oral rehydration salt and drink freely for 7 days. Increase the use of multivitamins and trace elements. Large groups use antibiotics to prevent secondary infections and reduce mortality. Maintain good ventilation and light.
