STANDARDIZATION OF SEROLOGICAL TESTS FOR DETECTING ANTI-TRYPANOSOMA-CRUZI ANTIBODIES IN DOGS

This paper reports on the standardization of four serological reaction s currently used in human serodiagnosis for the detection of anti-Tryp anosoma cruzi antibodies in naturally and experimentally infected dogs . Indirect immunofluorescence test (IFAT) and hemagglutination test (I HAT) were standardized, and complement fixation test (CFT) and direct agglutination test (DAT) were used for diagnostic confirmation. Four h undred and eighty one mongrel dogs that were studied by xenodiagnosis were use& (1) parasitemic dogs of two localities of endemic area (EA) of Santiago del Estero province in Argentina (n = 134); (2) non-parasi temic dogs of the same area (n = 285); (3) dogs experimentally infecte d with T. cruzi in the patent period (n = 6); (4) non-infected dogs (n = 56) which were born in the city of Buenos Aires (BA), one non-EA fo r Chagas' disease. For IFAT, parasitemic dogs EA showed 95% of reactiv e sera. Non parasitemic dogs EA showed 77% of non reactive sera. None sera from BA were reactive for dilutions higher than four. For IHAT, 8 4% of sera of parasitemic dogs EA showed serological reactivity and am ong non parasitemic dogs BA, 61% were non reactive, while the remainde r showed at most titres of 1/16 The cut-off titres for IFAT and IHAT w ere 1/16 and 1/32 respectively, and for CFT and DAT 1/1 and 1/128 resp ectively. Sensitivity for IFAT, IHAT, CF and DAT were 95%, 84%, 97% an d 95% respectively.