Molecular Detection And Species Identification Of Hemotropic Mycoplasma In Dairy Cattle From Southern Xinjiang

Hemotropic Mycoplasma is a common pathogen which parasite on the surface of red blood cells in human and animal,causing anemia,jaundice,fever and emaciation to the host.To understand and master the prevalence and species distribution of hemoplasmas in dairy cattle from southern Xinjiang,PCR method was used to detect and identify hemoplasmas in blood samples of dairy cattle in partial areas of southern Xinjiang.1.Based on the SSU r RNA gene loci of hemoplasmas,621 blood DNA samples of adult dairy cattle from scale farms and free-range breeding in southern Xinjiang were detected by PCR.A total of 180 samples were found to be positive for hemoplasmas,the infection rate was was 29.0%(180/621).The infection rate of hemoplasmas was 25.9%(38/147)and 30.0%(142/474)in large-scale breeding and free-range breeding,respectively.A total of 10 genotypes of M.wenyonii were identified.The two known genotypes were Mw-1(n=70)and Mw-2(n=21),respectively.Seven new genotypes were Mw-3(n=5),Mw-4(n=28),Mw-5(n=20),Mw-6(n=8),Mw-7(n=7),Mw-8(n=1),Mw-9(n=1)and Mw-10(n=1),respectively.A total of 4 genotypes of Candidatus Mycoplasma haemobos were identified.The two known genotypes were CMh-1(n=27)and CMh-2(n=2),respectively.Two new genotypes were CMh-3(n=6)and CMh-4(n=1),respectively.2.To further understand the prevalence of hemoplasmas in dairy cattle at different age groups,blood samples of 297 dairy cattle at 60 d,180 d,360 d and 720 d were collected from four large-scale dairy farms in southern Xinjiang,respectively.Based on the SSU r RNA gene locus of hemoplasmas of cattle,89 blood DNA samples were postive for hemoplasmas detected by PCR method,and the infection rate was 32.1%(89/277).The highest infection rate of hemoplasmas was 63.1%(41/65)in 720 d dairy cattle,followed by33.3%(23/69),31.7%(20/63)and 6.3%(5/80)in 360 d,180 d and 60 d dairy cattle,respectively.The infection rates of M.wenyonii and Candidatus Mycoplasma haemobos were 27.4%(76/277)and 9.7%(27/277),respectively,the mixed infection rate was 5.1%(14/277).A total of 12 genotypes of M.wenyonii were identified.The two known genotypes were Mw-1(n=33)and Mw-2(n=19),respectively.The ten new genotypes were Mw-10(n=6),Mw-11(n=5)Mw-12(n=5),Mw-3(n=2),Mw-13(n=1),Mw-8(n=1),Mw-14(n=1),Mw-15(n=1),Mw-16(n=1)and Mw-17(n=1),respectively.A total of 4 genotypes of Candidatus Mycoplasma haemobos were identified.The two known genotypes were CMh-1(n=24)and CMh-3(n=1).Two new genotypes were CMh-5(n=1)and CMh-6(n=1).In conclusion,prevalence of hemoplasmas is common in dairy cattle from southern Xinjiang,and M.wenyonii is the main infection species;The infection rate of hemoplasmas in dairy cattle was higher in free-range breeding than in large-scale breeding;The infection rate of hemoplasmas increased with the age of dairy cattle;Hemotropic mycoplasma in dairy cattle in southern Xinjiang show genetic diversity.The results of this study provide basic data for the related research on hemoplasmas of cattle in China.