Histological and Immunohistochemical Characterization of Vascular Alterations in Meninges of Cats Infected with Gurltia paralysans

Abstract

Gurltia paralysans, a metastrongyloid nematode, parasitizes in meningeal vessels in the thoracolumbar spinal cord of cats in South America and causes progressive paraparesis. Recently, the first report outside of South America described gurltiosis in a cat in Spain. As this parasitic disease has so far been largely neglected, especially outside of South America, the aim of the present case study was to add knowledge to the histologic and immunohistochemical characterization of central nervous lesions. To this purpose, formalin-fixed and paraffin-embedded (FFPE) tissue samples from the spinal cord and brain of five cats affected by clinical signs caused by Gurltia paralysans and of three control cats without CNS lesions were histopathologically examined using hematoxylin and eosin stain (HE), Elastica van Gieson stain, as well as periodic acid–Schiff (PAS) reaction. Moreover, immuno- histochemistry for alpha smooth muscle actin and Factor VIII-related antigen were performed to characterize vascular lesions. Lesions were consistent with previous descriptions and were mainly located in the spinal cord and consisted of chronic suppurative or lymphoplasmahistiocytic meningi tis as well as suppurative vasculitis, congestion and varicosis of meningeal veins. In view of the recent detection of this parasite in Europe and the increasing inner-European transport of rescued domestic cats, veterinarians in Europe should be aware of the clinical and pathomorphological presentation of this disease.

Gurltia paralysans: A Neglected Angio-Neurotropic Parasite of Domestic Cats (Felis catus) and Free-Ranging Wild Felids (Leopardus spp.) in South America

“…The presence of nematode larvae and pre-adult stages can be identified histologically in the subarachnoid veins of the spinal cord, associated with congestion, thrombosis, and thickening of the meningeal vessels ( Figure 4 B) [ 10 , 11 , 12 , 17 , 18 ]. The presence of suppurative thrombophlebitis and phlebosclerosis with mild smooth-muscle hypertrophy, moderate adventitial fibroplasia and marked subintimal fibrosis of the spinal cord venules have been reported [ 13 , 18 ]. The presence of perivenous fibrosis is considered evidence of chronic inflammatory stages [ 13 ].…”

“…The presence of suppurative thrombophlebitis and phlebosclerosis with mild smooth-muscle hypertrophy, moderate adventitial fibroplasia and marked subintimal fibrosis of the spinal cord venules have been reported [ 13 , 18 ]. The presence of perivenous fibrosis is considered evidence of chronic inflammatory stages [ 13 ]. In some specimens, concentric thickening of the venule wall may produce vascular stenosis [ 10 , 18 ].…”

“…White-matter lesions in the spinal cord segments may have variable degrees of Wallerian degeneration, characterized by distension of the myelin sheath diameter, irregular axons, axonal swelling, bulbous axonal fragmentation (caused by the presence of axonal spheroids), microcavitation and focal areas of mineralization [ 10 , 12 , 42 ]. Varicose venules can also be observed in the white matter of the spinal cord but are associated with recesses in meninges [ 13 , 42 ]. The activation of glial and endothelial cells and immune cell infiltration, visualized with immunohistochemical markers (e.g., GFAP, CNPase, factor VIII, CD3 and CD45R) in affected spinal cord samples indicate gliosis and chronic inflammatory spinal cord lesions subsequent to the ischemia caused by parasitic vascular injury [ 42 ].…”

“…Neurological signs are typically associated with neuroanatomical lesions observed in post mortem examinations and histopathological specimens within the spinal cord [1,[10][11][12]. Recently, histological and immunohistochemical characterization of vascular alterations in naturally G. paralysans-infected domestic cats of Chile unveiled suppurative vasculitis, haemorrhages, vascular congestion, and varicosis of not only spinal cord but also cerebrum-, cerebellum-and brain stem-associated veins [13], thereby supporting endothelium-derived pro-inflammatory innate immune reactions. [5] NA: not available; SSE: spinal subarachnoid space; PL: pelvic limbs; Myelo: myelography, My-lo-CT: computed tomography myelography; MRI: magnetic resonance imaging; CSF: cerebrospinal fluid; y: years; m: months.…”