Investigators documented the regional prevalence of Giardia species cysts in the feces of cats and tried to identify factors associated with infection. Samples were voluntarily submitted by owners and veterinarians from cats of all ages, sexes, breeds, and housing circumstances. A risk factor questionnaire was completed for all samples. Samples from 250 cats from Mississippi and northwestern Alabama were included in the study. Each was analyzed by using a centrifugation-flotation technique and a commercially available immunofluorescent antibody kit. Giardia species cysts and Cryptosporidium species oocysts were identified by using a fluorescent microscope. Fecal flotation was also performed if sample size allowed. The overall prevalence of Giardia species cysts was 13.6%. The presence of Cryptosporidium species oocysts, the presence of coccidial oocysts, and a clinical history of chronic gastrointestinal signs were significantly associated with presence of Giardia species cysts.

COMMENTARY: This study found a higher prevalence of Giardia species than previously reported, which may reflect greater sensitivity of the testing methods or a higher infection rate in this geographic area. It is also interesting that acute diarrhea was not associated with Giardia species but that chronic gastrointestinal signs were.

Prevalence and factors associated with fecal shedding of Giardia spp. in domestic cats. Vasilopulos RJ, Mackin AJ, Rickard LG, et al. JAAHA 42:424-429, 2006.