Diagnosis and treatment of Clostridium welchii in raccoon dogs

In August 2003, raccoon dogs farmed by an individual farmer were infected with diseases characterized by fever, dysentery, dyspnea and acute death. Clostridium welchii was diagnosed as raccoon dog by epidemiological investigation, clinical examination, pathological examination, bacteriological examination and serotyping.

1 morbidity

An individual farmer fed 64 animals, 8 fell ill and 4 died, with an incidence of 12.5% and a mortality rate of 50%.

2 clinical symptoms

The onset is acute, without any clinical symptoms and sudden death, the course of disease is generally 12-24 hours. Some patients suffer from loss of appetite and vomiting. The feces are liquid, green and mixed with blood.

3The pathological changes were examined by autopsy.

Subcutaneous tissue edema, pleural exudate mixed with blood-like exudate, diaphragm and pleura with bleeding spots; hepatomegaly, yellowish brown or yellow; small and large intestinal mucosa bleeding, appearance like blood intestine, intestinal content full of purple-black blood; mesenteric lymph node enlargement, bleeding; spleen section is purple-black; kidney slightly soft, cortex and medulla hemorrhage.

4 microscopic examination of smears of diseased materials

Gram-positive bacilli with flat ends were observed by microscopic examination of ileal contents and liver smears.

5 isolation and culture

Small pieces of liver tissue were aseptically taken and inoculated in anaerobic meat liver soup and cultured for 4 hours at 37 ℃, that is, a large number of air bubbles were produced above the culture medium. The aseptic liquid culture was transferred to the specific solid medium and put into the anaerobic cylinder and cultured for 48 hours at 37 ℃. The pure culture was obtained.

6 enterotoxin test

Take the obviously diseased ileal content 2mL, add the same amount of sterilized normal saline, shake evenly, 3000 rpm, centrifuge for 20 minutes, take the supernatant 0.1mL, give 20 g mice intraperitoneal injection, 1 hour after injection.

7 serotyping

The centrifuged supernatant 1mL cultured in anaerobic Megan Soup for 8 hours was mixed with the same amount of sera of C. welchii vaccine and incubated in 37 ℃ incubator for 40 minutes. The mixture of serum and toxin of A, B, C and D was injected intraperitoneally into mice, and the results were observed for 48 hours after injection. It was confirmed that the serotype of Clostridium welchii was type A.

8 Prevention and control measures

Raccoon dog clostridium welchii disease is characterized by acute onset, quick death, high fatality rate and sporadic distribution. the clinical treatment effect of the disease is poor, mainly based on prevention.

Ofloxacin, norfloxacin lactate, neomycin and chloramphenicol are highly sensitive drugs for the treatment of the disease. generally, neomycin is fed to feed according to 10mg per kilogram of body weight, twice a day for 3 or 4 days, and some results can be obtained.

8.2 many scholars believe that Clostridium welchii is a common flora in the digestive tract, which propagates rapidly in the gastrointestinal tract under specific circumstances and produces a large amount of toxins; high concentrations of toxins change intestinal permeability and enter the blood. cause systemic toxemia and cause disease. Microecological preparation is a kind of living bacteria preparation, which can effectively adjust the structure of intestinal flora and inhibit the growth and reproduction of harmful bacteria, so as to prevent the occurrence of the disease.