Serological and microbiological detection of Salmonella spp. in Rheas (Rhea americana)

The fast agglutination screening test, using S. Typhimurium as the antigen, was compared with the standard bacterial method to identify rheas (Rhea americana) contaminated with Salmonella spp. at slaughter. Seventy birds were serologically tested for Salmonella enterica Pullorum using a commercial antigen. Of these, 66 were also submitted to a macroagglutination test, using a strain of Salmonella Typhimurium isolated from rheas. All birds did not react with the commercial S. Pullorum antigen, but 37 were positive for the FAST-ST. The isolation of Salmonella spp. was verified in 66 (94.2%) birds. 85.7% were found in liver samples, 60% in feces and 42.3% in cloacal swabs. A total of 16.6% were identified as being S. enterica enterica rugosa, 35.9% as S. Typhimurium, 46.5% as S. Newport and 0.9% as S. Anatum. An insignificant concordance between the results of bacterial isolation and the serological response was observed (k=0.016). The detection of Salmonella spp. by bacteriological and serological methods in samples from rheas must be deemed important, because birds without a clinical manifestation can be significant sources of salmonellas in food infections.