Trypanosoma cruzi infection of squirrel monkeys: Comparison of blood smearexamination, commercial enzyme-linked immunosorbent assay, and polymerase chain reaction analysis as screening tests for evaluation of monkey-relatedinjuries

Background and Purpose: Wild-caught New World monkeys (NWM) from Central or South America are often infected with Trypanosoma species, including T. cr uzi, In humans, T. cruzi causes Chagas' disease. Even in closed monkey colo nies, T. cruzi can be propagated by blood-to-blood exposure, sexual activit y, and transplacental transmission. Animal handlers and laboratory staff wh o deal with blood and tissues from infected NWM are at risk for acquiring C hagas' disease via accidental exposure. Methods: We screened 162 blood samples from wild-caught Saimiri sp. monkeys for Trypanosoma species infections by use of blood smear examination, ELIS A, and polymerase chain reaction (PCR) analysis. Blood samples from 19 empl oyees with recent history of monkey-associated injuries also were tested. Results: Six percent (10/162) of the monkey samples were T. cruzi positive on the basis of blood smear examination results, 10.4% (17/162) were positi ve by ELISA results, and 26.5% (43/162) were positive by PCR results. Other organisms identified by PCR analysis included T. rangeli in two animals, P lasmodium spp, in two animals (P. malariae confirmed by PCR results) and mi crofilariae in one animal (morphologically, Mansonella perstans), Evidence of trypanosome infection was not found in the 19 employee samples on the ba sis of results of any of the three aforementioned tests, Conclusions: Close attention must be paid to worker safety where wild-caugh t NWM are used. The PCR analysis has a clear advantage over conventional te chniques (ELISA, blood smear) for screening NWM for trypanosome infections during quarantine and after employee injury.