Giardia duodenalis Genotyping from Dogs and Cats in Brazil: A Reality Still Unknown

Giardia duodenalis is possibly the first known intestinal protozoan in man. However, there are still many issues to be understood, especially in the field of taxonomy, which, with molecular studies, have presented great advances in understanding the epidemiological characteristics of G. duodenalis infection. Giardiasis is considered a zoonosis of public health importance, since G. duodenalis can infect a broad spectrum of mammalian hosts, including humans and domestic animals [1,2]. Thus, measures to control giardiasis should consider the participation of animals in the transmission cycles [3]. Currently the G. duodenalis species is divided into eight assemblages, classified in A-H [1,2]. The G. duodenalis assemblages C and D are still considered host-specific for canines and the assemblage F for cats, although they have already been observed in other animal species [4-6]. Assemblages A and B get more prominence because they have high zoonotic potential and can be found in humans and other mammalian hosts, including dogs and cats. As interest in domestic animals has grown in recent years and we have observed a growing humanization of dogs and cats, the existence of assemblages with affinity for humans and domestic animals (A and B) may support the occurrence of anthropozoonotic cycles inside the household [2,7].