The comparison of “tim” gene of Giardia lamblia in laboratory animals and human and the importance of cross transmission probability in Iran

BACKGROUND: 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.intestinalis) isolates have been variably divided into two or three genotypes by different investigators, and each group can be divided into subgroups. OBJECTIVES: 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. METHODS: 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. RESULTS: Among Giardia isolates, 2/10 and1/19 of PCR-RFLP of rabbit and mouse respectively amplified with primer PM290. CONCLUSIONS: 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.