Distribution Characteristics Of Four Intestinal Protozoa In Dairy Cattle In Ningxia

Eimeria,Cryptosporidium spp.,Giardia duodenalis and Enterocytozoon bieneusi are four important intestinal parasitic protozoa.These four pathogens are widely distributed and can cause different degrees of gastrointestinal diseases in the host,with particularly serious effect on dairy cattle,which can have a significant impact on their production performance.At the same time,zoonotic pathogens can also spread and infect humans and other animals.However,the distribution of these four pathogens in dairy cattle in Ningxia is very few reports currently.In this study,a total of 880 fresh fecal samples were collected from 10 large-scale dairy farms in four regions of Ningxia.Following,the infection rates,species,genotypes and subtypes of those four pathogens were investigated and analyzed by microscopic examination and molecular biology techniques to study the prevalence of these pathogens in Ningxia and to assess the risk and public health significance of their human-animal pathogens.1.The identification of Eimeria species and oocyst counts based on microscopic examination revealed that the total infection rate of Eimeria in Ningxia dairy cattle was 12.3%(108/880)and 12 species of Eimeria were identified by oocyst morphology,among which E.bovis(4.8%,42/880),E.zuernii(4.4%,39/880)and E.auburnensis(2.4%,21/880)were the dominant species in this study.Statistical analysis showed that the infection rate of Eimeria in dairy cattle was significantly correlated with different regions and ages(P≤0.01),but not with dairy cattle diarrhea(P>0.05).Oocyst counts of Eimeria positive samples showed that the average OPG was consistent with the positive rate,with the highest intensity of infection in cattle 5～7 months of age(1402.7),and the lowest intensity in cattle over 12 months of age(150.0).2.Based on SSU rRNA(Small subunit ribosome RNA)gene and gp60(60 kDa glycoprotein)site,the species identification and subtype differentiation of Cryptosporidium were carried out.The results showed that the total infection rate of Cryptosporidium in Ningxia dairy cattle was 16.1%(142/880),and four Cryptosporidium species were found,such as Cryptosporidium parvum(C.parvum,n=78),Cryptosporidium bovis(C.bovis,n=35),Cryptosporidium ryanae(C.ryanae,n=16)and Cryptosporidium andersoni(C.andersoni,n=13).Statistical analysis showed highly significant differences(P≤0.01)between different regions of Ningxia,different months of age,and different clinical signs of feces and the prevalence of Cryptosporidium infection in dairy cattle.2 subtypes,IIdA15G1(n=61)and IIdA20G1(n=5)were identified among 78 microscopic Cryptosporidium positive samples amplification and analysis of the gp60 locus.3.The positive rate and genotypes of Giardia duodenum in the samples were identified based on the bg(β-giardin)locus.The results showed that the prevalence of Giardia duodenum in Ningxia dairy cattle was 16.5%(145/880),and two types of assemblage E(assemblage E,n=143)and assemblage A(assemblage A,n=2)were detected.Among the different age groups,the prevalence of Giardia duodenalis infection in 3 to 4 month-old cattle was the highest at 26.5%(30/113),while the prevalence in 8 to 12 month-old cattle was 0.Statistical analysis showed that the prevalence of Giardia duodenalis infection in Ningxia cows was significantly correlated with different regions and months of age(P≤0.01).4.Based on the ITS(Internal transcribed spacer)locus,the detection and genotyping of Enterocytozoon bieneusi in the samples were carried out.The results showed that the infection rate of Enterocytozoon bieneusi in Ningxia dairy cattle was 10.0%(88/880).Statistical analysis showed that the infection rate of Enterocytozoon bieneusi in Ningxia dairy cattle was significantly different from different regions and months of age(P≤0.01).A total of 5 genotypes were detected in this study,namely BEB4(n=25),J(n=33),I(n=25),CHN4(n=4)and N(n=1).The genotype J,BEB4,I,and N belong to Group 2,and CHN4 belongs to Group 1.The above research results can help to understand distribution characteristics of the four intestinal parasitic protozoa in dairy cattle in Ningxia region and their zoonotic risk.It will be useful to formulate effective prevention and treatment measures according to different species,regions and ages,which can help to promote the healthy breeding of dairy cattle in Ningxia region.