Pseudomonas aeruginosa in chickens

Etiology

Pseudomonas aeruginosa belongs to Pseudomonas aeruginosa, gram-negative, short bacilli with blunt circles at both ends, can move, there is a flagellum at one end of the cell, the size of the bacteria is 1.5-3.0 μ m × 0.5-0.8 μ m, arranged alone or in pairs, occasionally short chains.

Epidemiology

The disease mainly harms chickens, mostly at the age of 1-35 days, with varying morbidity and mortality, sometimes as high as 50%, and there is no obvious seasonality. According to Liu Shanggao et al. (1987), the prevalent Pseudomonas aeruginosa in China is mainly serum Ⅳ type, which belongs to IATS9 type.

Pseudomonas aeruginosa is widely distributed in soil, water and air, and can be found in normal people, animal intestines and skin. Pseudomonas aeruginosa is usually found in traumatic infection, so the occurrence of Pseudomonas aeruginosa is related to environmental pollution and vaccine injection.

Symptom

The main manifestations of diseased chickens are reduced eating and low spirits; dysentery in varying degrees, fecal water samples, yellowish green, blood in seriously diseased chicken feces; abdominal dilatation, soft hand pressure, abdominal breathing in the later stage of diseased chickens; some diseased corns have varying degrees of edema around the corns, edema rupture and outflow of fluid, the formation of crusts, eyes completely closed or half-closed, tears; neck subcutaneous edema. Subcutaneous edema was also seen in the medial part of the legs of severely diseased chickens.

Pathological changes

The neck and navel of the diseased chicken showed yellowish green jelly-like infiltration, and there were bleeding spots or spots in the muscles. Visceral organs are congested and bleeding in different degrees. The liver is brittle and swollen, showing khaki, with grayish yellow spots of necrosis. The gallbladder is full. The kidney is enlarged with scattered bleeding spots on the surface. The lungs are congested, some see bleeding spots, pulmonary lobular inflammatory lesions, showing purplish red or marble-like changes. Coronary fat bleeding, and jelly-like infiltration, endocardial and epicardial bleeding spots. Glandular gastric mucosa exfoliated, musculogastric mucosa has bleeding spots, easy to peel off, intestinal mucosa hyperemia, serious bleeding. Splenomegaly, bleeding is small. The airbag is turbid and thickened.

The pathological changes of artificially infected chickens were green cellulitis at the injection site, atrophy of lymphoid tissue of immune organs and emptying of lymphocytes. Fibrinous degeneration around the splenic sheath artery, suppurative meningoencephalitis in most chickens, focal liver necrosis and interstitial myocarditis in a few chickens, hemorrhagic necrotizing inflammation of pulmonary lobules in some chickens.

Diagnosis.

The diagnosis of this disease, in addition to combining epidemic characteristics, clinical symptoms and pathological changes, mainly depends on the collection of disease materials for pathogen isolation and identification.

1. Collection, isolation and culture of diseased materials the subcutaneous edema fluids of heart blood, liver, spleen, lung and thorax and abdomen of dead chickens were inoculated on common broth, common Agar plate, blood Agar plate, McConkey Agar plate, SS Agar plate and other media for the isolation of this bacteria, respectively. The characteristics and color of the colonies were observed in 37 ℃ incubator for 18-24 hours. If the colony is blue-green, it can be preliminarily diagnosed as Pseudomonas aeruginosa.

two。 Laboratory diagnosis

(1) morphological observation: the pure culture was smeared and examined by Gram staining. The morphological characteristics of this bacteria can be described in the part of pathogen.

(2) examination of culture and biochemical characteristics: description of the same pathogen.

(3) Animal experiment: the 24-hour broth culture fluid was inoculated intraperitoneally with healthy chicks, each 0.2ml (2×109CFU / M1). At the same time, a control was set up. Pseudomonas aeruginosa can be re-isolated from the heart, liver, spleen, kidney and other organs of dead chickens.

Prevention and control measures

1. Strengthen feeding and management and do a good job in sanitary disinfection.

two。 The patients were treated with antibiotics and the drugs were selected according to the results of drug sensitivity test. Most reports believe that Pseudomonas aeruginosa is sensitive to gentamicin, polymyxin, carbenicillin and sulfadiazine and is effective in the treatment of this disease.

3. Pseudomonas aeruginosa is very resistant to most antibiotics, so it is necessary to develop biological products. However, it has not been reported that high immune serum or vaccine has been used to prevent and cure the disease. However, the typing of the main serotypes of Pseudomonas aeruginosa in China provides a scientific basis for the production of high immune serum or vaccine in the future.