The latex agglutination for Trypanosoma cruzi: unsuitable for testing animals
Minter-Goedbloed, E.; França, S.; Draper, C.C.
Journal of Tropical Medicine and Hygiene 83(4): 157-160
1980
ISSN/ISBN: 0022-5304 PMID: 6774105 Document Number: 161982
In an area in eastern Brazil endemic for Chagas' disease, 55 wild-caught opossums (Didelphis azarae and Metachirus nudicaudata) and 30 wild-caught rodents (Rattus rattus frugivorus, Nectomys squamipes, Oryzomys capito and Proechimys iheringi) were used to examine the suitability of latex agglutination test (Behringwerke ORIM 09 antigen) to screen animal reservoir hosts for T. cruzi infections. Animals were examined by direct microscopy, xenodiagnosis, latex agglutination and IFAT . A number of apparently uninfected wild-caught animals were experimentally infected with a human strain of T. cruzi and examined by xenodiagnosis, latex agglutination and IFAT. Opossum group showed a low sensitivity compared with xenodiagnosis. Wild rodents showed a low specificity compared with xenodiagnosis. Because of high proportion of non-specific positive agglutination tests among wild rodents, 37 uninfected laboratory rats and 10 mice were also tested. Rats (30) showed a positive latex agglutination. The high proportion of false positive latex agglutination results among uninfected rats is not understood. Experiments indicate that T. lewisi, T. conorrhini, T. rangeli and Haemobartonella muris are not the cause of observed cross reactions. The latex agglutination test is unsuitable as a screening test for T. cruzi infection of rats and opossums.