What is throat-locking wind? How to prevent and control throat-locking wind pig disease

This disease is a common respiratory infectious disease of pigs caused by Pasteurella multocida. It is characterized by septicemia and pharyngitis in the most acute type, fibrous pleuropneumonia in the acute type, and chronic pneumonia in the chronic type.

This bacteria exists in all tissues, body fluids, secretions and feces of diseased animals, and the upper respiratory tract of healthy livestock may also carry bacteria. Its resistance to physical and chemical factors is relatively low, and it dies quickly in the case of natural drying. The common concentrations of common disinfectants have good disinfection power to this bacteria. 1% carbolic acid or bleach powder and 5% lime milk can be killed in a few minutes to more than ten minutes. Sunlight has a strong bactericidal effect on this bacteria, and the thin bacterial layer is killed when exposed to sunlight 10min. This bacteria is not heat-resistant. Heating 60 ℃ lmin can kill the culture of Martin broth for 24 hours.

1. Clinical symptoms

The occurrence of the disease has no obvious seasonality, when the environmental hygiene condition is poor or due to cold, cold wave, sudden climate change, poor ventilation, stuffy crowding, lack of nutrition, feed contaminated feed, drinking water, utensils and external environment, healthy pigs can be transmitted through the digestive tract; infected pigs can be transmitted through the digestive tract by coughing and sneezing, and can also be transmitted through the respiratory tract through droplets. In addition, infection can also occur through the vectors of blood-sucking insects and wounds on the skin and mucous membranes. The incubation period of the disease is 1-5 days, which is generally divided into the most acute type, acute type and chronic type according to the course of the disease. Most of the first two types were septicemia and pleuropneumonia. the lesions of chronic type were concentrated in respiratory tract and showed chronic pneumonia.

1.1 the most acute type is mostly seen in the early stage of the epidemic, commonly known as "throat locking wind". It often eats normally at night, dies suddenly in the early morning, and no clinical symptoms are observed. The course of the disease is slightly longer with high fever (41 ℃-42 ℃), general weakness, loss of appetite, lying on the floor, dyspnea, rapid heartbeat, restlessness. The pharynx is feverish, swollen and hard. In severe cases, local swelling can extend to the ear root and neck. When breathing is extremely difficult, the dog often shows sitting neck breathing, blood-like foam from the mouth and nose, visible mucosal congestion, cyanosis, erythema on the ear root, neck, abdomen and medial skin of the extremities. The course of the disease is 1-2 days, the condition deteriorates rapidly after the emergence of respiratory symptoms, and dies quickly, and the death rate can be as high as 100%.

1.2 Acute type is the main and common type of disease. In addition to septicemia, there are also symptoms of acute pleuropneumonia. Elevated body temperature (40-41 ℃), early spastic dry cough, nasal mucus, dyspnea, and then wet cough. Palpation has pain in the chest and auscultation has rales and friction sounds. With the development of the disease, breathing is more difficult, open mouth and tongue, showing a dog sitting type, visible mucosal cyanosis, purulent conjunctivitis. Constipation followed by diarrhea, end-stage heart weakness, rapid heartbeat, skin blood stasis or small bleeding. Sick pigs can't afford to lie on the ground, and most of them die of asphyxiation. The course of the disease was 5ml / 8d, and those who had tolerated it turned to chronic type.

1.3 chronic type showed symptoms of chronic pneumonia and gastroenteritis. Often have persistent cough and dyspnea, mucous secretions from nasal flow. Sometimes there are scab-like eczema, joint swelling, loss of appetite, and often diarrhea. Pigs with progressive malnutrition, emaciation and weakness, who were not treated in time, died after more than 2 weeks of failure.

2. Pathological changes.

2.1 the most acute hemorrhagic serous infiltration of mucous membrane, serosa and subcutaneous tissue. A large amount of yellowish jelly-like edema can be seen under the skin of the neck, and the edema can spread to the forelimbs. Acute pulmonary edema. The whole body lymph nodes and spleen bleed, but the spleen is not enlarged; there are small bleeding spots in epicardium and pericardium; hemorrhagic inflammation in gastrointestinal mucosa.

2.2 Acute systemic mucous membrane, serosa, parenchyma organs and lymph node bleeding, characterized by fibrinous pneumonia. The lung has liver degeneration, edema and emphysema; the long course of liver degeneration area has necrosis, lung, "bni- serous infiltration, section marble change. Pleura often has fibrous material attachment, severe chest and lung adhesion, pleura and pericardial effusion. Pleural lymph nodes are enlarged, the section is red, succulent. There is a large amount of foamy mucus in the trachea and bronchi, and the mucosa is inflamed.

2.3 chronic type. The body was extremely emaciated and anemic. The lung and liver degeneration area is vast, the necrotic focus is surrounded by connective tissue, there are cheese-like substances, and some form cavities. Pericardium and pleural effusion, there are fibrous substances in the pleural cavity, often adhesion to the lungs.

3. Clinical diagnosis

Combined with the characteristics of epidemiology, clinical symptoms and pathological changes, a preliminary diagnosis can be made, and the diagnosis should be tested by etiology. It is advisable to take disease materials, such as lung lymph nodes, spleen, liver, or body fluids such as neck edema fluid and pleural effusion, ear vein blood smears can be taken for microscopic examination, and a diagnosis can be made if a large amount of gram-negative bipolar strongly stained microbacilli are found. bacterial culture, isolation and identification should be carried out if necessary.