Giardiasis in laboratory-housed squirrel monkeys: a retrospective study.

Giardia infection was diagnosed in a 1.5-year-old, group-housed, female squirrel monkey with diarrhea. A retrospective study was undertaken to evaluate the incidence of Giardia in the 190-member colony. Records were analyzed to determine whether any one of the following conditions applied: the animal had clinical signs referable to the gastrointestinal system; a fecal examination for ova and parasites was performed; gastrointestinal parasitism was revealed by necropsy; or a culture of samples from the gastrointestinal tract was performed. Analysis revealed a total of 19 monkeys, 68% (13/19) of which had gastrointestinal clinical signs. Giardia cysts were recovered from 33% (4/12) of monkeys with gastrointestinal signs in which fecal examinations were done. The yearly incidence of diarrhea in the colony was low at 0.61%; however, 33% (2/6) of the monkeys with diarrhea were positive for Giardia. Six animals had blood in the feces or rectal prolapse, in the absence of diarrhea, and 30% (2/6) of these animals were positive for Giardia. Of six animals without gastrointestinal clinical signs, 50% (3/6) had giardiasis, which was listed as an incidental finding. In light of these findings, an additional 16 healthy animals were examined for Giardia. Giardia cysts were recovered from 50% (3/6) of males and 70% (7/10) of females from which samples were obtained. Additionally, clean water consumed by the animals was negative for Giardia cysts, and facility waste water was positive. To our knowledge, this is the first report of giardiasis in squirrel monkeys.