The Serodiagnosis of Toxoplasma gondii Infection in Felines Measured by an Enzyme-Linked Immunosorbent Assay (ELISA)

Abstract

An enzyme-linked immunosorbent assay (ELISA)was developed for the detection and quantitation of feline Toxoplasma gondii (T. gondii) antibodies. This assay was shown to be more sensitive than the Indirect Hemagglutination (IHA) test and equivalent to the Indirect Fluorescence Antibody (IFA) test. It was established that the assay was linear allowing a single dilution for quantitation of antibody and positive values were reliable with a mean intra-assay coefficient of variation of 5.13% and a mean inter-assay coefficient of variation of 6.20%. The temporal antibody response was monitored for one year on ten Specific Pathogen Free (SPF) cats, eight of which were infected with viable T. gondii organisms. Two uninoculated cats were held as controls. The serum antibody levels to T. gondii of these ten experimental cats were determined by ELISA, IFA, and IHA. Fecal samples collected concomitantly with the first month bleeds showed no oocyst shedding occurred during the acute rise in antibody titer. Complete blood counts performed periodically over the course of the study revealed a slight rise in eosinophil counts in most cases, which is indicative of the antigen antibody response to parasites such as T. gondii. In overall performance ELISA demonstrated the sensitivity and accuracy essential for use as a veterinary diagnostic tool in the monitoring of toxoplasmosis in the Felidae family.