Evaluation of the precipitin reaction as a laboratory test for equine infectious anemia

Abstract

The purpose of this study was to: (1) determine if the precipitin reaction is a reliable test for the laboratory diagnosis of equine infectious anemia (EIA), and (2) explore other laboratory tests and compare them with the precipitin reaction. The precipitin reaction was evaluated through the utilization of the "ring-test" technique. The antibody (precipitin) was prepared by harvesting serum from rabbits which had been inoculated intravenously with washed red blood cells (RBCs) taken from horses with EIA. The antigen (precipitinogen) was prepared by harvesting serum from blood of horses experimentally inoculated with the EIA virus. The evaluation of the precipitin reaction was based on a study of 15 horses. Thirteen of the horses were experimentally infected and one horse was a naturally infected inapparent carrier of the EIA virus. One horse was utilized as a non-infected control animal. The 15 horses were observed and bled daily for periods up to 100 consecutive days. This resulted in a total of over 800 daily samples being available for study. The blood samples served as a source of serum for the precipitin test as well as hermatologic examinations. The mean 10-minute erythrocyte sedimentation rate (ESR/10) and packed cell volume (PCV) were determined daily. Siderocyte counts were determined periodically. In addition, on approximately 600 daily samples, serums were subjected to protein fractionation by paper electrophoresis. Albumin/globulin (A/G) ratios and serum protein patterns were determined from the electrophoresis results. ...