Prevalence And Species Identification Of Theileria And Anaplasma In Goats From Partial Areas Of Shaanxi Province

Theileria and Anaplasma are two important tick-borne blood protozoas,widely distributing in many counties and districts.Theileria and Anaplasma mainly infected small ruminants in tropical and subtropical regions,seriously threatening animal health and decreasing the productivity of animals.Shaanxi province is the mian province of goats and sheep and holds a great number of local varieties.The objective of the present study was to systematically investigate the prevalence and species of Theileria and Anaplasma in different goat breeds within different age groups from partial areas of Shaanxi province,using microscopic examination and sequence analysis.1.A total of 509 blood samples were collected from 14 farms in Mizhi,Suide,Qingjian,Sanyuan,Lantian,Linyou and Zhenba counties in Shaanxi province.By Giemsa staining and microscopic examination,a total of 268(52.7%)blood samples were positive for Theileria infection.Three types of parasites were observed,including round(1.0 ?m-2.2 ?m),ovoid(0.9-1.1 ?m×1.7-3.0 ?m)and rod(0.8-1.2 ?m×1.7-3.0 ?m)shapes.Significant differences(P < 0.01)in prevalence were observed among different areas in our study,with the highest in Zhenba county(92.6%,112/121)but none in Sanyuan county.Significantly different prevalence(P < 0.01)was also found among different species.The highest was detected in Shaanan white goats(92.6%,112/121),following by Guanzhong diary goats(55.1%,125/227)and Shaanbei white cashmere goats(22.3%,31/139),but no infections were found in Saanen dairy goats.The prevalence was also significantly different(P < 0.01)among four age groups,with the highest(76.7%,46/60)in goats of 7-12 months and the lowest(19.2%,19/99)in goats of 3-6 months.Single band was observed in all microscopically positive samples through PCR amplification targeting the SSU rRNA gene of Theileria.Sequence analysis revealed the existence of two Theileria species in these animals,namely T.luwenshuni and Theileria sp.OT3.Of them,T.luwenshuni was identified as the predominant species widely distributed in Mizhi,Suide,Qingjian,Lantian and Linyou counties,while Theileria sp.OT3 was only found in dairy goats over 12 months from Linyou county.2.The total prevalence of Anaplasma infection in 509 blood samples collected from 14 farms in seven counties was 58.5%.Significant differences in prevalence(P < 0.01)were observed among seven counties in our study.The prevalence in Zhenba county(84.3%,102/121)was extremely significantly higher than other origins but no infections were detected in Sanyuan county.Significant differences in prevalence(P < 0.01)were also found among different goat breeds,with the highest in Shaannan white goats(84.3%,102/121),following by Shaanbei white cashmere goats(58.3%,81/139),Guanzhong dairy goats(50.2%,114/227)and Saanen dairy goats(4.5%,1/22).The prevalence in different age groups was also significantly different(P < 0.01),with the highest in goats of 0-2 months(80.0%,12/15)and the lowest in goats of 3-6 months(44.4%,44/99).Phylogenetic analysis showed three Anaplasma species in these investigated areas,including A.bovis,A.ovis and A.phagocytophilum.A.bovis were found in all age groups of goats in Linyou,Lantian,Mizhi,Suide,Qingjian and Zhenba counties.A.ovis were found in all age groups in Linyou,Mizhi,Suide and Qingjian counties.A.phagocytophilum were mainly distributed in all age groups in Linyou,Lantian,Suide,Qingjian and Zhenba counties.Of 509 blood samples,114 blood samples(22.4%,114/509)were co-infected with two or more pathogens,while six blood samples(1.2%,6/509)were infected with all three pathogens.Of different goat breeds,A.bovis were detected in all goat breeds.A.phagocytophilum were detected in Guanzhong dairy,Shaanbei white cashmere and Shaannna white goats,while A.ovis were only detected in Guanzhong dairy and Shaanbei white cashmere goats.Collectively,the infections of Theileria and Anaplasma were revealed in goats from partial areas of Shaanxi province.The prevalence of Anaplasma was slightly higher than that of Theileria,and two Theileria spp.(T.luwenshuni and Theileria sp.OT3)and three Anaplasma spp.(A.bovis,A.ovis and A.phagocytophilum)were detected.These findings provided the basic data for implememntion of control measures against infections of Theileria and Anaplasma in goats from Shaanxi province as well as other parts of China.