| Giardia duodenalis is a zoonotic parasite which mainly causes host diarrhea with worldwide distribution,At present,8 assemblages(A-H)have been identified.Equine animals can be infected with 4assemblages(A,B,E and G).among them assemblage B infection is the most common.In this study,microscopic observation and PCR were used to examine the infection of Giardia duodenalis in some parts of Guangdong,and Identify its assemblage in order to provide basic data for the investigation and research of giardiasis in racehorse for our country.1.Collecting 430 fresh feces samples of adult racehorses from 7 equestrian clubs in Guangdong Province.In this study,we used Saturated Sucrose Solution Floating Method and Lugol’s iodine solution staining method to conduct microscopic examination of collected fecal samples.The results showed that 6of the 7 equestrian clubs were positive for intestinal parasite infections,the infection rate ranged from0-54.3%(19/35),and the total infection rate was 14.9%(64/430);a total of 3 were detected Species/parasite eggs/cysts,the infection rate of Giardia cysts was 2.6%(11/430);the infection rates of Strongylus and Parascaris equorum were 11.4%(49/430)and 0.9%,respectively(4/430),the infection rate of intestinal parasites in female horses,male horses and gelding horses was 16.1%(5/31),6.8%(3/44)and15.8%(56/355),respectively.2.Based on the SSU r RNA gene locus of Giardia duodenalis,PCR was used to detect 430 racehorse stool DNA samples,and 42 samples were found to be positive.The total infection rate was 9.8%(42/430),which was higher than the result of microscopy.(2.6%,11/430).Among them,the Huangpu District Equestrian Club has the highest infection rate of Giardia duodenalis at 34.3%(12/35),while the Huizhou District has the lowest infection rate at 8.2%(11/134).Zengcheng and Huadu district have the lowest infection rate.No infection was found in racehorses in these district;the results of the survey of intestinal parasites in racehorses of different sexes showed that male horses had the highest infection rate of Giardia duodenalis at 13.6%(6/44),and the infection rates of female horses and gelding horses were respectively These are 12.9%(4/31)and 9.0%(32/355).The 42 positive samples of Giardia duodenalis were sequenced and compared and analyzed.A total of 3 types of assemblage were identified,namely zoonotic assemblage A(n = 4)and zoonotic assemblage B(n = 36)and assemblage E(n = 2).3.Based on Giardia duodenalis triose phosphate isomerase gene,glutamate dehydrogenase gene andβ-giardin gene loci,42 racehorse Giardia duodenalis were positive by PCR method The isolates were subjected to a multi-site sequence typing study,and 12,9 and 1 positive products were successfully amplified respectively;the obtained sequence was identified and analyzed,and there were 3 genotypes at the tpi site,among which assemblage B(n = 10)There is 1 genotype,assemblage A(n = 1)has 1 genotype,assemblage E(n = 1)has 1 genotype;bg locus has 3 genotypes,among which assemblages There are two assemblage in B(n = 7),and one assemblage in assemblage E(n = 1);and one gdh locus has one genotype,which is identified as assemblage E.Only one assemblage E isolate was successfully amplified at three sites at the same time,forming one MLG.The results suggest that Giardia duodenalis from racehorse in Guangdong Province is genetically stable and does not have diverse genetic distribution characteristics.To sum up,racehorse in Guangdong Province is commonly infected with Giardia duodenalis,and zoonotic assemblage B is the dominant infection assemblage.Its genotype is relatively single and does not have diverse genetic distribution characteristics.The research results provide basic data for the investigation and research of animal Giardia duodenalis in my country. |
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