| Giardia lamblia is opportunistic pathogenic intestinal protozoa in the world,it can be cross-transmitted between human and animal. According to statistics, Giardia is the most common intestinal parasites of sheep, that can infected all ages sheep, otherwise,is the main pathogen in young lambs. In recently reported, Zoonotic Giardiagenotype were found in sheep. Giardia duodenalis can cause predominant clinical symptom of host, such as diarrhea or absorbefacient barrier and so on. To understand the prevalence of Giarida infection in sheep in Henan Province, 716 fecal samples were collected from nine sheep farms in Henan Province during July 2009 to June 2010. All the samples were stained with Lugol's iodine solution for identify the pathogens,and sametime, the seasonal dynamics of giardia in sheep in one of nine sheep farms was studied during one year. Molecular characteristics of positive samples from previous study were researched used TPI and GDH gene.In order to understand the infected condition and epidemiological characteristics of Giardia in Henan Provice, samples of fresh stool obtained from sheep, which were detected for cysts of Giardia duodenalis by microscope of aldehyde-ether precipitation method and iodine wet mount smears between July 2009 to June 2010. 47 of the 716 fecal specimens were diagnosed as Giardia positive, the Giardia infection rate was 6.7%. The infection rate of sheep aged 0-3 months was 12.4%, 3-6 months was 13.1% respectively. There was a significant difference prevalence of Giardia in sheep in the different age groups.The purpose of this study was also to investigate the seasonal variation of Giardia duodenalis in sheep in Zhongmu , the prevalence of Giardia in sheep was investigated on one farm in more than 1 year. 47 of the 716 fecal specimens were diagnosed as Giardia positive .The results showed that the infection rates were 20.7% in summer, 4.8% in autumn, 6.2% in winter respectvely .Giardia infection was not found in spring,that may be not only related with the age, area, breeding condition, but also the seasonal variation.In order to identify genotype or subtype of Giardia duodenalis isolates of sheep in Henan Province. 81 microscopy-positive samples were took to be amplified by nested PCR used TPI and GDH gene. Using nest-PCR to amplify TPI gene of Giardia duodenalis, the results showed no positive in stool samples and 53 positive samples were amplified from fecal samples.The sequence length of products were 530bp. Using nest-PCR to amplify GDH gene of Giardia duodenalis, the results showed no positive in stool samples and 17 positive samples were amplified from fecal samples.The sequence length of products were 510bp.Then, Blast tool was used to search homological sequences in NCBI, after that, homological sequences were alignmented. Phylogenetic tree and homological analysis were made by some biological softwares such as Clustal X 1.81 and DNAstar 4.0. The presence of one predominant genotype of Giardia duodenalis in the samples examined, assemblage E, with 28 samples belonging to assemblage E, 6 samples belonging to assemblage A2. Subtyping was identified by sequence analysis of the TPI gene and GHD gene. The results suggest that Giardia exist within the different genotypes or subtypes, and have differences base between subtypes.The zoonosis genotypes A2 was found in sheep in this study,so it is of significance important significance of public health to research the giardiasis of sheep.Investigation of Giardiasis and molecular characteristics of Giardia in sheep have not been reported in China.Therefore, The present study results will provide a reference for research the Giardia of sheep such as molecular epidemiology, biologic characters and the relationship of germ line evolution between the isolates. |
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