Update on the diagnosis and management of Giardia spp infections in dogs and cats.

I i t a r a o t A p t t l d s n iardia spp are flagellates that are found in the intestinal tract of humans and domestic and wildlife animals, inluding birds and amphibians, worldwide. The genus Giardia ontains multiple species, which are for the most part morphoogically indistinguishable. Recognized species of this genus are . duodenalis, G. agilis, G. muris, G. microti, G. ardeae, and G. sittaci. Giardia duodenalis (syn. G. intestinalis or G. lamblia) s the species that infects people, dogs, and cats and is considered species complex. There are at least 7 distinct assemblages A-G) based on genetic analyses (Table 1). Host specificity was elieved to be minimal, but there have been varying results oncerning cross-infection potential of Giardia spp. Not all mall animal isolates cause disease in human beings. Assemlage A has been found in infected humans and many other ammals including dogs and cats. Assemblage B has been ound in infected humans and dogs, but not cats. There are pecific genotypes of Giardia that commonly infect dogs (asemblages C and D) and cats (assemblage F).1-3 There are 2 stages of Giardia spp in its life cycle, the rophozoite and the cyst. The teardrop-shaped trophozoite s the active, motile form that is found in the intestinal tract. t is approximately 15 m long and 8 m wide (Fig 1). The llipsoidal-shaped cyst is the environmentally resistant stage ainly responsible for transmission; it is approximately 12 m ong and 7 m wide (Fig 2). Trophozoites can be found in the feces f dogs or cats with diarrhea, but rarely survive for a significant eriod outside the host. In contrast, cysts are very resistant and can urvive several months outside the host in wet and cold conditions, ut are susceptible to desiccation in dry and hot conditions.