Clostridium perfringens, also called Clostridium sinensis enteritis or rabbit enterotoxemia, is mainly characterized by acute watery diarrhea and high mortality caused by Clostridium perfringens type A and its toxins.
On May 10, 2006, more than 500 rex rabbits in a certain rabbit farm in the Economic and Technological Development Zone of Jilin City developed morbidity and died. The five dead rabbits were sent to a veterinarian hospital of the Jilin Agricultural Science and Technology Institute for necropsy and were newly diagnosed as Clostridium perfringens. The disease was diagnosed as Clostridium perfringens type A after laboratory tests and was controlled after treatment.
1 Clinical symptoms
It is understood that Rex Rabbit has no obvious symptoms before the onset, and diet and spirit are also normal. Some mornings were eating normally. At noon, they were able to move freely and suddenly died in the afternoon. Some had no abnormalities in their diet and activities in the previous day. On the second day they found that they had died in rabbit cages. The course of the disease is very short. There is also an anorexia at the beginning of the disease in rabbits. The patient is depressed, has a half-closed eyelid, has an abdominal distension, and finally dies at the mouth. He usually dies in a few hours, and the rabbit dies 1 to 2 days. death. An acute water leak occurs, and the anus is contaminated with feces around the back and hind limbs, and there is rancid odor.
2 pathological changes
After the necropsy, 5 cases were found to be full of contents and gas in the stomach, and the gastric mucosa was eroded and shed. The stomach, duodenum, and jejunum mucosa were heavily congested. In particular, there were many black bleeding plaques at the bottom of the stomach. Segment ulcer or necrosis; large amount of hemorrhage in the intestine, abdominal odor, small intestinal full of jelly-like liquid, thin and transparent intestinal wall, mesenteric lymph node enlargement, hemorrhage; liver enlargement, brittle texture, fragile, Yellow patches; gallbladder swollen, dark green bile; swollen spleen with bleeding plaques; blood stasis in the kidneys, brown urine in some bladders; Dendritic, intracardiac, and epicardial distribution of small bleeding points.
3 Diagnosis
3.1 smear microscopy
Dead rabbit jejunal contents, liver and spleen were used to make contact lenses. Gram staining and microscopic examination revealed that a large number of Gram-positive bacilli were found and the cells were larger. The two ends were blunt and neat, showing single scattered or double-stranded chains. Arrangement, decidua, no buds.
3.2 Bacterial culture
The liver and jejunal contents of rabbits were aseptically taken and inoculated into liver broth. After incubation at 37° C. for 5 to 6 hours, the culture fluid became cloudy and a large amount of gas was generated. Take culture media smear microscopy, the results are the same as above. This culture was inoculated on blood agar medium and anaerobically incubated at 37° C. for 24 hours to produce a circular circle with a double hemolyzed ring, a neat edge, a smooth surface bulge, and light gray colonies approximately 2 mm in diameter.
3.3 Animal testing
The contents of the jejunum of dead rabbits were made of a 1:5 suspension of physiological saline, centrifuged at 3000r/min for 20 min, and the supernatant was taken and added to the double antibody, and then injected into the abdominal cavity of 8 healthy mice, 0.5 mL each. Two mice were used as the control group. As a result, mice in the experimental group died within 24 hours after the injection, while the control group survived.
3.4 Biochemical tests
The cultured strains were used for sugar biochemical tests. The results are shown in Table 1.
In addition, the bacteria can also liquefy the gelatin, and the invading fermentation phenomenon occurs in the inoculated milk culture medium.
3.5 Neutralization test
The supernatant after centrifugation was mixed with the antiserum of Clostridium perfringens type A, B, C, and D. After 40-50 minutes of exposure, they were inoculated into the abdominal cavity of 2 mice, 0.5 mL/only within 24 hours. All but one of the other groups died except for the A group and the control group all survived. In summary, it can be diagnosed as type A clostridium welchii.
4 treatment
4.1 The dead rabbits were buried deeply and the rabbits were treated with isolation. At the same time fixed hand feeding, tools, feeding equipment dedicated.
4.2 Emergency immunizations were carried out on the unresected puppies with the aluminum hydroxide inactivated seedlings of type A clostridium perfringens.
4.3 The rabbits were injected with high-immune serum of Clostridium perfringens type A according to 3 to 5 mL/once, twice a day, every other day.
4.4 diseased rabbit oral olaquindox, 5mg per kilogram of body weight, while injecting kanamycin, 20mg per kg body weight, and with intraperitoneal injection of 5% glucose saline, 20 ~ 50mL / only, once every 3 to 5 days.
4.5 Use 3% caustic soda solution to completely disinfect the rabbit house and the environment. The sink and trough should be soaked with 0.1% benzalkonium bromide so that the epidemic can be controlled.
5 Prevention
Clostridium perfringens type A is a conditional pathogen, so it should adhere to the principle of prevention.
5.1 In the breeding process, more feeds with high crude fiber content are fed to reduce the pressure in the gastrointestinal tract of rabbits.
5.2 To strengthen the environmental management of rabbit houses, attention should be paid to timely ventilation, rabbit house disinfection and warm-keeping work.
5.3 regular injection of type A clostridium perfringens inactivated aluminum hydroxide vaccine.
5.4 For newly introduced rabbits, they must be observed in isolation before entering the field.
6 Summary and discussion
The main reason for this disease was the feeding of a large amount of concentrate and insufficient crude fiber content. In addition, the field was built near the airport and the noise was high. Together with the unsatisfactory effect of disinfecting drugs, the humidity in the rabbit house was very large, and eventually led to the occurrence of this disease.
With the continuous development of the rabbit breeding industry, the disease has also shown an upward trend. After the onset of morbidity, it will be extremely quick and it will cause great economic losses. Therefore, we must strengthen the prevention of this disease.
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