Acute hemorrhagic meningoencephalomyelitis due to erratic migration of Aelurostrongylus abstrusus in a kitten

INTRODUCTION. The cat lungworm Aelurostrongylus abstrusus occurs worldwide, including in Brazil (da Silva Lima et al., 2021 Pathogens 10:595). Although clinical aelurostrongylosis is a typical respiratory disease, sporadic cases of non-respiratory signs, e.g. life-threatening diarrhea caused by intestinal larval invasion, have been documented (Philbey et al., 2014 J. Comp. Pathol. 150:357-60). This study describes the first case of a fatal neurological disease due to A. abstrusus in a kitten. MATERIALS AND METHODS. A 3 months-old kitten was presented to a veterinary clinic in Barra do Piraí, Brazil, with dehydration, pale mucous membranes, abasia and posterior bilateral myoclonus. The clinical picture of the kitten dramatically worsened, with generalized flaccid paralysis and death few days after hospitalization. As the histological examination revealed the presence of nematode stages, samples from lung, cerebellum and spinal cord were subjected to PCRs-coupled sequencing protocols specific for Gurltia paralysans, Troglostrongylus brevior and A. abstrusus (López-Contreras 2020, Animals 10:1169; Morelli et al., 2021 Pathogens 10:454). RESULTS AND CONCLUSIONS. Areas of hemorrhagic necrosis in the left frontal telencephalic cortex, cerebellum and brainstem were found at necropsy. Subarachnoid hemorrhages were present in the cervical and lumbar tract of spinal cord. Lung histology revealed embryonated eggs and nematode sections in the alveolar lumen, atelectatic and emphysematous areas, mild congestion and lymphocytic/histiocytic inflammation. Larval nematodes were also present in the subarachnoid space of the brain and the spinal cord; these tissues had hemorrhages/congestion and cerebral lymphocytic, eosinophilic and neutrophilic infiltrates. Samples were PCR-positive with 100% identity with A. abstrusus from Colombia (Accession Number MH779453). This study shows that aelurostrongylosis may be fatal in young animals and describes for the first time a fatal neurological aelurostrongylosis due to larval embolization in the central nervous system, causing an acute hemorrhagic meningoencephalomyelitis. Similar neurological phenomena have been documented in dogs infected with the closely related angiostrongylid Angiostrongylus vasorum (Bourque et al., 2008 Can. Vet. J. 43:876-9; Wessman et al., 2006 Vet. Rec. 158:858-63). Hence, further studies are necessary to elucidate if unusual localizations and migration of A. abstrusus are more frequent than expected.