Evaluation of two fecal examination techniques for detection of Trypanoxyuris spp. infection in owl monkeys (Aotus nancymae)

Infections of Trypanoxyuris spp. pinworms in Aotus nancymae and other New World primates are typically subclinical, but infection during experimental use could confound interpretation of experimental data. Further, Trypanoxyuris species are highly infective, and rapid diagnosis is important to prevent an outbreak in the animal colony. This study sought to determine whether a fecal flotation technique was sensitive enough to replace the perianal tape test for diagnosis of Trypanoxyuris spp., thereby reducing stress to the animal and sample collection time. On days 0 and 3, we collected fecal samples from 45 animals confirmed to be infected with Trypanoxyuris spp. by perianal tape testing. Fecal samples were evaluated by both a commercial analysis system and by sucrose flotation with centrifugation. For both detection methods, no significant difference in sensitivity was detected between tests conducted on day 0 versus day 3. The sensitivity of repeated commercial tests was 80%, significantly higher than the 60% for sucrose flotation. The commercial test was significantly more sensitive than sucrose flotation, indicating that the commercial system was a better method for detecting Trypanoxyuris spp. However, sensitivity of only 80% confers a considerable risk of false negatives, thereby potentially delaying treatment and further contributing to environmental contamination. In our opinion, neither method of fecal analysis was a suitable replacement for the perianal tape test to diagnose Trypanoxyuris spp. in owl monkeys.