Intra Vitam Diagnosis of Neglected Gurltia paralysans Infections in Domestic Cats (Felis catus) by a Commercial Serology Test for Canine Angiostrongylosis and Insights into Clinical and Histopathological Findings—Four-Case Report

Abstract

Gurltia paralysans is a metastrongyloid nematode which belongs to the Angiostrongylidae family and presents tropism for veins of the subarachnoid space in vivo of domestic and wild felids causing a progressive and chronic clinical manifestation of paraparesis/paraplegia. The geographic distribution of G. paralysans includes rural and periurban areas of South America and was recently reported in Europe. To date, a definitive diagnosis of feline gurltiosis is still conducted by post-mortem examination of the spinal cord in affected animals. A presumptive diagnosis of feline gurltiosis can also be achieved based on data of compatible clinical signs and associated epidemiological risk factors. The aim of this preliminary study was to evaluate the commercial serological test Angio Detect TM® (IDEXX Laboratories) as a possible diagnostic method of feline gurltiosis in vivo. For the study, 10 domestic felines (Felis catus) which originated from a high endemic area of Southern Chile, were analyzed. All felines presented chronic paraparesis or severe paraplegia. Subsequently, commercial Angio Detect TM® serological tests for the detection of closely related Angiostrongylus vasorum in canids were performed according to manufacturer's instructions. Conducted serological tests were positive in seven of ten felines showing paraplegia/paraparesis and presumably infected with G. paralysans, and four of them were additionally necropsied, and presented macroscopic findings compatible with feline gurltiosis. Furthermore, the presence of adult female and male G. paralysans specimens at the level of the subarachnoid vasculature in affected spinal cord segments were observed during necropsy. Histopathology demonstrated severe eosinophilic meningomyelitis, coagulopathies with thrombosis in G. paralysans-parasitized leptomeningeal veins. Results of this preliminary study suggest a cross-reaction between A. vasorum-specific antigens, which also parasitize blood vessels in vivo, and G. paralysans when using an Angio Detect TM® test, which suggests its helpful use as a new diagnostic method for feline gurltiosis in live domestic felines. Additional specific antigen research will be required in order to better understand the sensitivity and specificity of A. vasorum antigens used in this test and for existing cross-reactivity with G. paralysans-derived antigens for future a suitable intra vitam immunodiagnosis of neglected feline gurltiosis.

Gurltia paralysans: a neglected parasite of domestic cats

“…A cross-reactivity of G. paralysans and A. vasorum using a commercial serological test developed for the diagnosis of canine angiostrongylosis in domestic dogs has been recently evaluated for the use in domestic cats with gurltiosis. Preliminary results showed that the Angio Detect Test™ (IDEXX Laboratories), a rapid test designed to detect circulating antigen based on A. vasorum-specific antibodies, can be used as an effective test for cats displaying clinical signs of G. paralysans infection (Gómez et al 2020).…”

The Neglected Angio-Neurotrophic Parasite Gurltia paralysans (Nematoda: Angiostrongylidae): Northernmost South American Distribution, Current Knowledge, and Future Perspectives

“…Microscopic findings include vascular myelitis and intralesional adult parasites, which principally locate at subarachnoid space in some segments of the spinal cord (third thoracic vertebra to third lumbar vertebrae and fourth lumbar vertebrae to third sacral vertebrae) [38,39]. The gurltiosis intra vitam diagnosis is highly challenging due to the lack of evidence in the excretion of G. paralysans eggs and larvae stages, neither in feces nor in other body secretions [42], because the environmental stages and parasite transmission route remain unknown. Veterinary clinicians should include exhaustive clinical examination in cats with typical hind limbs neurological signs and complementary tests to approach the diagnosis of this parasitosis.…”

“…They suggested a cross-reaction between Angiostrongylus vasorum and G. paralysans-specific antigens, which could be used as a new diagnostic tool for feline gurltiosis. Nevertheless, it is necessary to analyze the sensibility and specificity compared with the specific antigen for this parasite to validate the serological test result [42].…”

Felid Parasitoses, New Insights and Open Perspectives

“…An important difficulty in investigating the occurrence of this parasite is the fact that the diagnostic stage is unknown and diagnosis to date is only achieved in post mortem examination. In their study, Gómez et al [14] evaluated a commercial serological test, designed for the diagnosis of canine angiostrongylosis due to Angiostrongylus vasorum, for an intra vitam diagnosis of G. paralysans infection in cats. According to the results, a cross-reaction between A. vasorum-specific antigens and G. paralysans offers the possibility of using this antigen test as a diagnostic method for feline gurltiosis in live domestic cats.…”

“…According to the results, a cross-reaction between A. vasorum-specific antigens and G. paralysans offers the possibility of using this antigen test as a diagnostic method for feline gurltiosis in live domestic cats. Furthermore, this study presents the clinical and histopathological findings of four cases of feline natural infections, providing important insights on this neglected and little-known feline parasite [14].…”