Equine nocardioform placentitis, typically caused by bacteria such as Crossiella equi or Amycolatopsis spp., is a devastating disease that often results in premature birth, intrauterine growth retardation, or abortion of late-term foals. Recent investigations suggest that the degree of disease is correlated with the area of placenta that is affected.
Very little is known regarding how mares are exposed to these organisms and experimental models of infection have failed to reproduce the disease. Farms that attempt to screen for the disease do so with their veterinarian trying to identify characteristic lesions in the placenta via trans-abdominal ultrasound. Unfortunately, not all cases are detected, and those that are detected may be advanced prior to detection. Additionally, this type of testing is not specific for nocardioform placentitis. As a result, there is a significant need for the development of a specific, non-invasive means for screening mares for nocardioform placentitis and monitoring their treatment.
While there have been significant outbreaks of nocardioform placentitis recently during 1999, 2011, and 2017, the intermittent nature of this disease has hampered research progress in search of a better understanding of this complex problem. During the 2020 foaling season, a significant increase in nocardioform placentitis cases diagnosed at the University of Kentucky’s Veterinary Diagnostic lab was noted and a coordinated effort undertaken to collect and store samples from confirmed cases of nocardioform placentitis and unaffected control mares. Stored serum samples from this effort will be used in this project to develop a test to detect antibodies specific to the most common bacterial species known to cause nocardioform placentitis. Additionally, prospective and serial samples will be collected from central Kentucky farms for further investigation of exposure timeframes. As such, the goal of this project is to: (1) develop an enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of antibodies against Crossiela equi or Amycolatopsis spp., (2) use the ELISA to better understand infection dynamics and exposure periods, and (3) implement an early-warning system for potential outbreaks on central Kentucky horse farms.