comparison of [TIM] gene of Giardia lamblia in laboratory animals and human and the importance of cross transmission probability in Iran

Giardia has the ability to infect many mammals including dogs, cats, deer, mice, ground squirrels, chinchillas, swine, rabbits, pocket mice, oxen, guinea pigs, and humans. Giardia lamblia [also Giardia duodenalis G.intes-tinalis] isolates have been variably divided into two or three genotypes by different investigators, and each group can be divided into subgroups. We have compared the triosephosphate isomerase [tpi] sequences of these genotypes by polymerase chain reaction- restriction fragment length polymorphism [PCR-RFLP] to determine G.lambia genotype in Iran for the first time. In this study, 4 sets of primers were used in which 2 sets were designed by other investigator, and 2 sets were designed by the authors of the present study to confirm the results of the first two primers and also to differentiate the subgroups. Among Giardia isolates, 2/10 and 1/19 of PCR-RFLP of rabbit and mouse respectively amplified with primer PM290. There is evidence that suggests that direct transmission from companion animals to human does occur. Zoonosis is controversial regarding Giardia; however, most researchers believe that its zoonotic potential merits adequate precaution when working with feces of animals that may be infected

Detection of the [Tim] gene of sheep Giardia using [Tim] Gene primers of Giardia with human origin

Giardiasis is an important human parasitic disease. Giardia is a genus composed of binuclear flagellate protozoa. Giardia duodenalis is a parasitic species for a wide range of vertebrates, including humans. Heterogeneity in G. duodenalis has been shown by serological, biochemical, and molecular analysis. In the present study, the possible genetic similarity between Giardia in sheep and humansand their probable zoonosis was investigated. Direct examination and formalin ether concentration technique were performed on the contents and tissues of sheep intestines. The gradient sucrose method was applied to collect and purify cysts, and DNA extraction was performed by the phenol-chloroform method. Only very small amounts of DNA could be extracted after repeated freezing, thawing and suspension with lysis buffer, after which polymerase chain reaction [PCR] was performed for DNA amplification by primers that were designed for Giardia of human origin. The gene, [triose phosphate isomerase] [tim or tpi], was selected as the molecular marker and two sets of primers [PM290, PM924] were used. We examined 308 sheep stool samples in our study, including 21 positive samples. Cultures for Giardia were negative. Three sheep isolates were determined by a 290 base pair [bp] amplicon that were similar to certain human types. The similarity of the sheep and human genomic characters of Giardia implies the possibility that there is transmission of these protozoa between humans and sheep