Abstract
Giardia duodenalis is an enteric parasite that has distinct genetic groups. Human infections are mainly caused by assemblages A and B, although sporadic infections by assemblages C and D have also been reported. Animals can be infected by a wide range of assemblages (A to H). The aim of this study is to identify the assemblages and sub-assemblages of G. duodenalis with zoonotic features in fecal samples of school-aged children, and in dogs that coexist in the same households in Lages, Santa Catarina, Brazil. Fecal samples of 91 children and 108 dogs were obtained and G. duodenalis cysts were detected in samples from 11 (12.08%) children and 10 (9.25%) dogs. DNA extracted from the 21 positive samples was analyzed by PCR-RFLP, using the gdh gene. Results showed the presence of sub-assemblages AI (2/11), AII (4/11), BIII (2/11), and BIV(3/11) among children and AI (5/10) and BIV(3/10) in dogs, with zoonotic characteristics, and the carnivore specific assemblage C (2/10). G. duodenalis was found to infect both children and dogs living in the same household, with the same sub-assemblage (BIV) indicating that pet dogs are a potential risk of transmission of G. duodenalis to humans.