Parasitic encephalitis caused by Stephanurus dentatus in a pig in Brazil

A pig was in left lateral recumbency with limb spasticity, accentuated prostration, and strabismus, and was euthanized. During autopsy, yellowing of the leptomeninges at the ventral pons to medulla oblongata was noted. In the cerebellar peduncles, there was a focally extensive black-to-yellow area at the level of the vestibular nuclei. Histologic examination revealed a cross-section of a nematode larva, consistent with Stephanurus dentatus, bordered by edema and marked infiltration of mononuclear cells, plasma cells, and a few eosinophils. Vacuolation of the neuropil, with rare gitter cells and axonal spheroids, was also observed. We diagnosed parasitic encephalitis caused by S. dentatus migration based on the pathology findings and characterization of the parasite.

Detection of Stephanurus dentatus in wild boar urine using different parasitological techniques

Stephanurus dentatus is a nematode that parasitizes the urinary tract of domestic and wild Suidae, especially in tropical areas. However, there is a lack of information about stephanurosis in wild boar (Sus scrofa), thus making it necessary to develop sensitive techniques with which to diagnose this pathogen in order to carry out further research. In Spain, the high prevalence of this nematode has been evidenced in Doñana National Park (DNP). The objective of the present work is twofold. The first is to compare the efficacy of three parasitological techniques to detect S. dentatus eggs in the urine of infected wild boar: (i) gravity sedimentation, (ii) sedimentation by centrifugation, and (iii) flotation techniques, while the second is to determine whether the quantification of eggs can serve as an indicative value of the host's parasite intensity. In order to accomplish these purposes, 27 wild boars from DNP were necropsied, and the urinary system of each animal was examined in order to determine parasite intensity. While all the aforementioned techniques can be used to detect eggs in urine, the most effective in terms of egg quantification are sedimentation by gravity and by centrifugation, as they allow a greater number of S. dentatus eggs to be detected. However, none of the results obtained with these techniques significantly correlated with the number of adult nematodes parasitizing the host, signifying that counts in urine can provide guidance on only the parasite intensity of wild boar.