Cerebrospinal fluid eosinophilia is a sensitive and specific test for the diagnosis ofParelaphostrongylus tenuisin camelids in the northeastern United States

Abstract

Abstract. Aberrant migration of Parelaphostrongylus tenuis in camelids results in neurologic deficits, recumbency, and sometimes death. An antemortem diagnosis of P. tenuis in camelids is typically based upon the presence of characteristic asymmetric neurologic deficits, known exposure to white-tailed deer, cerebrospinal fluid (CSF) eosinophilia, and response to treatment. The diagnostic accuracy of CSF eosinophil percentage for the diagnosis of P. tenuis in camelids has not been critically examined. The objective of the current study was to determine the sensitivity (Se) and specificity (Sp) of CSF eosinophil percentage, CSF eosinophil concentration, total nucleated cell concentration, and protein concentration for the antemortem diagnosis of P. tenuis. Medical records of camelids admitted to Cornell University with clinical signs of neurologic disease, CSF analysis, and necropsy were examined from January 2000 through December 2009. Se and Sp were determined by receiver operating characteristic curves in camelids diagnosed with P. tenuis (n = 13) or other conditions (n = 24) based on postmortem examination. More than 17% of eosinophils in CSF had a Se of 85% and Sp of 92% for P. tenuis diagnosis (area under the curve [AUC]: 0.87; SE AUC: 0.07; P < 0.0001; 95% confidence interval [CI] AUC: 0.72-0.96), and >1.4 eosinophils/µl of CSF had a Se of 85% and Sp of 96% (AUC: 0.9; SE AUC: 0.06; P < 0.0001; 95% CI AUC: 0.76-0.97). Cerebrospinal fluid eosinophil percentage and concentration are sensitive and specific methods for diagnosing P. tenuis antemortem in camelids residing in regions endemic to white-tailed deer.

Cerebrospinal Nematodiasis in 20 Camelids

“…The most common deficits involved cranial nerves II, VII, and VIII. In a previous study, only 8% of the population presented with cranial nerve deficits, and the affected nerve(s) was not identified . Eighty percent of the camelids in our present study that presented with cranial nerve deficits failed to survive.…”

“…The geographical distribution of the disease relies on the presence of both hosts in the same location. Although the disease is mainly found in eastern North America, it has been reported in areas of central North America as well …”

“…The onset of clinical signs may be gradual, with animals presenting ataxic or exhibiting a wide‐based stance, or affected animals may be found acutely recumbent. Although there is no definitive antemortem test for CN, the majority of affected camelids have eosinophilic pleocytosis of cerebrospinal fluid (CSF) . Although the presence of eosinophilic pleocytosis in camelids presenting with neurologic signs does not definitively diagnose CN, the paucity of other diseases that induce CSF eosinophil production allow CSF analysis to presumptively diagnose CN in most cases.…”

“…Although the presence of eosinophilic pleocytosis in camelids presenting with neurologic signs does not definitively diagnose CN, the paucity of other diseases that induce CSF eosinophil production allow CSF analysis to presumptively diagnose CN in most cases. In a retrospective study, only 8% of camelids presenting with neurologic signs and CSF eosinophilic pleocytosis were not diagnosed with CN (1 was diagnosed with Toxoplasma gondii and a conclusive diagnosis was not made for the other camelid) . A CBC and serum biochemical analysis (SBA) often are reported to be unremarkable, but the majority of available reports are from experimental infection with P. tenuis , describe a single case, or are anecdotal .…”

Retrospective study of central nervous system lesions and association with Parelaphostrongylus species by histology and specific nested polymerase chain reaction in domestic camelids and wild ungulates

“…14, 15 The likelihood of finding a nematode during gross necropsy and/or histology is remote, and therefore diagnoses are often inconclusive. Histologic lesions of the central nervous system (CNS), that characterize P. tenuis infection are similar to Baylisascaris procyonis in human, nonhuman primate, and avian hosts and include axonal degeneration and swelling, perivascular cuffing, the presence of hemosiderin-553427V DIXXX10.1177/1040638714553427Diagnosing P. tenuis with histology and PCRDobey et al…”