Comprehensive Diagnosis And Pathogenicity Of Deer Intestine Toxemia In Shandong Area

Clostridium perfringens is also described as bacillus aerogenes capsulatus.The causative agent of the bacterium was the genus Clostridium of the family Bacillaceae,belonging to mild anaerobic bacteria(G+)with obtuse ends.Clostridium perfringens was divided into 5serotypes(A,B,C,D,and E)based on the major lethal toxins,namely alpha(CPA),beta(CPB),epsilon(ETX),and iota(ITX).However,Clostridium perfringens can produce up to twelve toxins(??????????? and ?).Four kinds of toxins(????? and ?)play the main pathogenic role.According to the different toxins produced by bacteria,the bacteria can be divided into five serotypes A-E.The bacteria can cause death,enteritis or enterotoxemia in pigs,cows and chickens.In this paper,a comprehensive diagnosis of deer enterotoxemia was made and pathogenicity test of the isolated strains was carried out.Sudden death of deer occurred in a certain area of Shandong Province.The deer had typical clinical symptoms of venom enterotoxemia.The mortality rate of the deer was over50%.The patients were all young and middle-aged deer with good nutrition.The dead deer showed abdominal distention.Pathological examination showed complete stiffness,cyanosis of mucosa,hemorrhagic spots or diffuse hemorrhage of different sizes in all organs.Histopathological examination showed that a large number of cells were necrotic and diffuse hemorrhage were seen in the intestinal tract.Microscopic examination of smears of intestinal contents revealed a Gram-positive bacillus with Bacillus capsular.After culture in anaerobic environment,the shape of TSC agar plate was round,protuberant,smooth surface,and the center of the colony was black.On the yolk agar plate,round colonies grey to gray-yellow with smooth and translucent surface formed opaque bands around and at the bottom of the colonies.The result of bacterial biochemical test was consistent with that of Clostridium welchii.By multiplex PCR and 1.5% gel electrophoresis,it was found that only a bright band appeared at 324 bp.Compared with the reference strain sequence of NCBI,it was found that the sequence of the 12 isolates had more than 98% homology with other publishedClostridium welchii sequences,indicating that the isolate was Clostridium perfringens type A.The pathogenicity of enterotoxin and Clostridium perfringens type A isolated from chickens and mice was also tested.Through genotyping,it was found that Clostridium perfringens type A is still prevalent.