News: Update on a Serological Diagnostic Assay for P. tenuis

Maine Department of Inland Fisheries and Wildlife
New Hampshire Fish & Game Department, Wildlife Division
New York State Animal Health Diagnostic Center
Vermont Fish and Wildlife Department


05/28/2019

Researchers at the College of Veterinary Medicine, University of Tennessee, Knoxville, let by Dr. Richard Gerhold, are developing a serological diagnostic assay for Parelaphostrongylus tenuis (meningeal worm or brain worm). P. tenuis is a parasitic nematode found in various cervid species including deer, elk (Cervus canadensis), and moose (Alces alces). In cervids other than the parasite’s definitive host, white-tailed deer (Odocoileus virginianus), the parsite can migrate extensively in the central nervous system leading to ataxia or other neurological deficiencies and death. Techniques currently available for a definitive diagnosis of the parasite involve a necropsy to detect the worm in the brain and spinal cord via histological exam and/or PCR.  Unfortunately this testing is expensive, time consuming and has low sensitivity due to inability to often detect the parasite. Our aim is to develop a rapid, inexpensive, sensitive and specific serological test to detect P. tenuis antibodies in banked or live animal serum. Initially we utilized a previously published peptide. Western blots were utilized to identify anti-P. tenuis antibody present in blood, serum and spinal fluid using sera from known positive animals. However, due to inconsistent results using this protein and cross reactivity with other similar organisms, we moved our attention to a full genomic analysis of P. tenuis which led to identification of a novel P. tenuis-specific peptide. Preliminary ELISA results utilizing this novel peptide disclosed good reactivity to serum of moose with confirmed P. tenuis infection and minimal reactivity to elk serum from western Wyoming where P. tenuis is not known to occur.  

Additional probing with P. tenuis negative sera will further help establish cut off values and determine the assay’s sensitivity and specificity. We will continue to evaluate the efficacy of the novel peptide for use in the ELISA and expect to have the validation process complete by May 2019. Dr. Gerhold would be grateful for anyone who could send serum from P. tenuis confirmed or highly suspect infected cervids (confirmation by histologically detecting the worm or migration tracts in CNS) to use as further positive controls in the validation process.