| The southern Xinjiang region is rich in geographic features that provide suitable living conditions for a variety of arthropods.Moreover,South Xinjiang is one of the major livestock breeding regions in China and a major producer of meat and dairy products as well as leather products in China.As a widespread arthropod on the body surface of animals,the Melophagus ovinus is the second most common body surface Parasite(Paris,France)in Xinjiang,in addition to ticks.It is mainly parasitic on the animal’s body surface causing skin and hair damage,and transmits a variety of pathogenic microorganisms through the hemophilic route.Rickettsiosis and anaplasmosis are important pathogens affecting animal health and human health and have been neglected by farmers and breeding enterprises because of the insignificant clinical signs and long incubation period,but the threat of this pathogen to public health and animal husbandry still exists.In this study,to understand the prevalence of rickettsia and anaplasma in M.ovinus and sheep blood in South Xinjiang,samples were collected from 236 sheep body surfaces in 9 counties of South Xinjiang from June2021 to March 2022,and a total of 621 samples including 558 M.ovinus and 63 sheep blood samples were collected.Polymerase chain reaction(PCR)and sequencing methods were used to detect rickettsia and anaplasma in621 samples.For rickettsiae,based on the MLST method,the seven-gene tandem sequence 17-k Da-glt A-rrsgene D-omp A-omp B-sca1 was applied to identify rickettsiae species,and the MEGA7.0 software was applied to construct a multigene association evolutionary tree to investigate the species and prevalence of rickettsiae in M.ovinus and blood of sheep in South Xinjiang China.The results showed that two species of rickettsiae were detected,Candidatus R.barbariae and R.massiliae,with an overall infection rate of 14.8%(92/621),including 12.1%(75/621)for Candidatus R.barbariae and 2.7%(17/621)for R.massiliae,and 81 samples in M.ovinus positive and 11 samples in sheep blood Positive reactions.PCR amplification of the Msp4 gene was applied for the detection of anaplasma,and the sequencing results were used to construct genetic evolutionary trees and analyze their genetic evolutionary relationships using MEGA7.0 software.The results showed that a total of one amoeboid pathogen was detected,A.ovis and the total infection rate of this pathogen was 28.7%(178/621),and four genotypes were analyzed: III,GB3,Ao GOv3,and XJ9,with infection rates of 15.8%(98/621),7.9%(49/621),4.0%(25/621),and 1.0%(6/621),respectively.A total of157 positive samples were detected in M.ovinus and 21 positive samples were detected in sheep blood.Coinfection with rickettsia and anaplasma was present in 6 samples in this survey all from M.ovinus.Statistical analysis revealed the highest prevalence of total pathogens in samples collected from border areas(Moyu,Wuqia and Wushi)with 50.9%(57/112),49.4%(38/77)and 66.2%(47/71),respectively.To the best of our knowledge,the detection of Candidatus R.barbariae and R.massiliae tentatively in M.ovinus in this study,as well as the detection of sheep amoeboid genotypes GB3,Ao GOv3 and XJ9 are reported for the first time in M.ovinus.In conclusion,a total of 621 samples were collected from nine regions in southern Xinjiang in this study.The presence of Candidatus R.barbariae,R.massiliae and A.ovis pathogens in both M.ovinus and sheep blood was confirmed by PCR assay tentatively.This study completes the situation of rickettsiae and A.ovis in M.ovinus in the southern border area of China.These findings provide an important reference for the new understanding and prevention of rickettsiae and anaplasma in the border areas of China. |
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