| Popis: |
The vector-borne protozoan parasiteTrypanosoma cruzicauses Chagas disease in humans, dogs, and many other mammalian hosts. Canine Chagas disease is increasingly diagnosed in dogs of the southern US where triatomine insect vectors occur, and there are limited veterinary diagnostic options; currently, only the indirect fluorescent antibody (IFA) test is offered at a single accredited diagnostic laboratory. This study evaluated a multiplex microsphere immunoassay (MIA) for detecting antibodies againstT. cruziin dogs and compared with existing serological methods to establish cut-off values and relative sensitivity/specificity. Dog sera (n=135) which were previously characterized using the IFA and off-label use of two commercial rapid assays were tested on the multiplex MIA against 12 different antigens: nineT. cruziantigens, a negative control recombinant protein (green fluorescent protein), aLeishmaniaantigen, and a canine parvovirus antigen (used as an antibody control given near-ubiquitous parvovirus vaccination). For each sample, the ratio of median fluorescence intensity (MFI) for eachT. cruziantigen to that of GFP was calculated. Samples with an antigen/GFP ratio greater than 4 standard deviations above the mean of 25 known negative sera were considered positive on that antigen. Samples testing positive on 2 or more antigens were considered positive forT. cruziantibodies. Compared to the IFA, the multiplex MIA demonstrated a relative sensitivity of 100% and specificity of 96.97%. Given its precision, high-throughput format, potential for automation, and lack of subjective interpretation, the multiplex MIA should be considered a valid and improved assay forT. cruziantibodies in dogs. |
