Investigation On The Main Pathogens Of Calf Diarrhea In Henan Province And Analysis Of Two Pathogens

Calf diarrhea is known as the killer of newborn calves,which brings huge economic losses to pastures and seriously restricts the healthy development of cattle industry.Because some pathogens also have the potential risk of zoonotic disease,they also pose a certain threat to public health safety.The main diseases causing diarrhea in calves are viral diarrhea virus,rotavirus,coronavirus,Escherichia coli K99+,Mycobacterium paratutilis,Cryptosporidium and so on.In this study,the prevalence of the main pathogens of calf diarrhea in Henan Province was investigated,and the subtypes of intestinal microsporidia and Mycobacterium paratutilis were analyzed,so as to provide a reference for the prevention and control of diarrhea and local public health safety in calves.1.Experiment 1 investigation on the main pathogens of diarrhea in calves in Henan Province.In order to investigate the epidemic situation of the main pathogens of calf diarrhea in Henan Province,to understand the etiology of calf diarrhea,to prevent and control calf diarrhea more effectively,and to promote the healthy development of cattle industry.A total of 187 fecal samples and 305 blood samples of calves aged 1～6 months with and without diarrhea in 12 areas of Henan Province were collected.the samples were detected by ELISA.A total of 17(BVDV)positive blood samples of viral diarrhea virus were detected,the detection rate was 5.57%,13 positive blood samples of Mycobacterium paratuberculosis,the detection rate was 4.26%。187 calf fecal samples,47 of them were Cryptosporidium parathyphoid positive samples.The detection rates were 25.13%,3 rotavirus positive samples(1.60%),8 E.coli K99+positive samples(4.28%)and 5 coronavirus positive samples(2.67%).The main cause of diarrhea in calves was pathogenic infection.the infection rate of Cryptosporidium parvum was the highest,mainly caused by a single pathogen.According to the epidemic situation of pathogens in each area,it provides a reference for the prevention and control of diarrhea in calves.The molecular identification of enterosporidium bischi from a calf of henan province was carried out2.Experiment 2 Molecular biological identification of intestinal microsporidia of calves in Henan Province.In order to understand the situation and molecular biological characteristics of intestinal microsporidia of calves in Henan Province,based on ITS gene,In this experiment,nested PCR was used to detect and identify intestinal microsporidia in feces of 187 calves(diarrhea and no diarrhea symptoms)in 12 areas of Henan Province,and 9 positive samples were obtained.The total infection rate was 4.81%(9/187),the detection rate in different areas was 6.67%,15.38%,and the detection rate in Pingdingshan area was the highest 15.38%,(2/13).The detection rate was 10.81%(4/13)in Zhengzhou area,7.69%(2/26)in Xuchang area,and the lowest in Kaifeng area.It was 6.67%(1/15);no detection was found in the rest of the area.The results of sequence comparison showed that there were 6 reported genotypes,including J(n=4),I(n=1),BEB4(n=1),CHC8(n=1),Peru 10(n=1)and Hnnan-IV(n=1),among which the detection rate of genotype J was the highest.The proportion of positive samples was 44.44%(4/9).Phylogenetic evolution showed that Peru 10 was in group 1,and,J(n=6),I(n=1),BEB4(n=1),CHC8(n=1)and Peru10(n=1)were all located in group 2,which was at risk of potential zoonosis.3.Experiment 2 Identification and genotype analysis of Mycobacterium paratyphoid tuberculosisIn order to investigate the infection of Mycobacterium paratubicans in calves in Henan Province,PCR method was used to detect and identify Mycobacterium paratuberculosis in feces of calves in Henan Province(diarrhea and no symptoms of diarrhea).The nucleotide sequence of Hinfl restriction site was predicted by on-line restriction endonuclease simulation,and the genotype of Mycobacterium paratutilis was identified.A total of 11 positive samples were detected,the detection rate was 5.88%.Only positive samples were detected in Zhengzhou,Jiaozuo and Jiyuan,the lowest detection rate was 5.41%(2/37)in Zhengzhou,followed by 27.2%(6/22)in Jiaozuo.The detection rate of Jiyuan was the highest(33.33%,2/6),but not in other areas.Three subtypes of Mycobacterium paratuberculosis were identified as Mycobacterium paratuberculosis bison type(n=6),sheep type of Mycobacterium paratyphoid(n=4)and Mycobacterium paratuberculosis bovine type(n=1).The percentage of.Mycobacterium paratubicans detected was 54.55%,36.36%and 9.09%,respectively.