Validation of a multiplex microsphere immunoassay for detection of antibodies to Trypanosoma cruziin dogs

Autor: Rodriguez, Carlos A., Busselman, Rachel E., Shen, Huifeng, Saunders, Ashley B., Tarleton, Rick, Hamer, Sarah A.
Zdroj: Journal of Veterinary Diagnostic Investigation; November 2023, Vol. 35 Issue: 6 p704-709, 6p
Abstrakt: The vector-borne protozoan parasite Trypanosoma cruzicauses Chagas disease in humans, dogs, and many other mammalian hosts. Canine Chagas disease is increasingly diagnosed in dogs of the southern United States where triatomine insect vectors occur, and there are limited veterinary testing options; only the indirect fluorescent antibody (IFA) test is offered at a single accredited diagnostic laboratory. We evaluated a multiplex microsphere immunoassay (MIA) for the detection of antibodies against T. cruziin dogs and compared it with existing serologic methods to establish cutoff values and relative sensitivity and specificity. We tested 135 canine sera that had been characterized using the IFA and off-label use of 2 commercial rapid assays with our multiplex MIA against 12 antigens: 9 T. cruziantigens, a negative control recombinant protein (green fluorescent protein, GFP), a Leishmaniaantigen, and a canine parvovirus antigen (used as an antibody control given near-ubiquitous parvoviral vaccination). The median fluorescence intensity (MFI) ratio between each T. cruziantigen and GFP was calculated for every sample. Samples with an antigen:GFP MFI ratio > 4 SDs above the mean of 25 known-negative sera were considered positive to that antigen. Samples testing positive to ≥ 2 antigens were considered positive for T. cruziantibodies. Compared to the IFA, our multiplex MIA had a relative sensitivity of 100% and specificity of 97.0%. Given its precision, high-throughput format, potential for automation, and lack of subjective interpretation, our multiplex MIA should be considered a valid and improved assay for T. cruziantibodies in dogs.
Databáze: Supplemental Index