Evaluation of the detection of antibodies against Lawsonia intracellularis and changes in serum biochemistry in foals with and without equine proliferative enteropathy

Abstract

Equine proliferative enteropathy (EPE) is a well-recognized disease in foals caused by Lawsonia intracellularis. The aim of this study was to analyse clinicopathologic parameters and antibody titres up to the diagnosis of EPE. During the 2019 season, all foals born on a large breeding farm in Germany were enrolled in a monitoring program for EPE from four to nine months of age, including evaluation of rectal temperature, white blood cell count as well as serum total protein and albumin. 42 foals developed EPE between September 2019 and January 2020. Data sets of these foals and 83 age matched control foals were included in this study. All affected foals showed hypoproteinaemia and 39/42 showed hypoalbuminaemia at the onset of EPE. Total protein and albumin decreased rapidly within 7.5 days on average before the diagnosis of EPE. Both total protein and albumin values were significantly lower in the EPE-group compared to the matching foals (p < 0.0001). Seroconversion was observed in all 42 affected foals and in 50/83 matching foals. At the time of diagnosis, affected foals had a significantly higher titre compared to the matching foals (p < 0.0001). Nevertheless, the titre increased significantly between the preceding sampling and the week of diagnosis in both groups (p < 0.0001). Faecal qPCR for Lawsonia intracellularis revealed positive results in 22/42 affected foals. Based on the data analysed here, a high IPMA-titre does neither indicate protection against EPE nor a definite diagnosis of EPE, as both healthy foals and those with clinical EPE show a positive antibody titre against Lawsonia intracellularis.