Clinical Application for the Detection of Meningeal Worm Infection Using a Newly Developed Real-Time PCR Assay

Principal investigator:

Antoinette Marsh
The Ohio State University
College of Veterinary Medicine
February 1, 2024 – September 1, 2025
$17,322

Parelaphostrongylus tenuis, meningeal worm, is a neurotropic nematode that causes neurological and ocular disease in aberrant host species (camelids, goats, cattle, wildlife, sheep, and horses). White-tailed deer (Odocoileus virginianus) harbor the adult worms which release offspring shed in the deer feces. Terrestrial gastropods (snails and slugs) acquire and propagate the juvenile parasite to an infective stage for the next host, white-tailed deer, or aberrant hosts. Aberrant species are exquisitely sensitive to the parasite’s migration to the spinal cord and brain tissue. To identify P. tenuis infection while the animal is still alive is limited to an indirect method, the evaluation of the cerebrospinal fluid (CSF) cell populations. Numerous eosinophils, absence of other cell types, and clinical signs provide a presumptive, but not a definitive diagnosis. Lastly, if the CSF becomes contaminated with blood during the acquisition procedure, then the cytologic evaluation is difficult. Our group developed a real-time PCR test for P. tenuis DNA. We plan to evaluate this test in known and presumptive cases of P. tenuis (post-mortem confirmed or eosinophilic CSF samples) as well as clinically normal animals. We will also evaluate the impact of blood contamination of the spinal fluid to determine if a “bloody tap” interferes with the test. Finally, we plan to sequence DNA from selected positive cases to ensure this assay’s internal probe will work with geographically distinct parasites. The project goal is to have this real-time PCR test clinically validated so diagnostic laboratories can utilize it in molecular-based testing panels.