Elusive Angiostrongylus vasorum infections

The parasitic nematode Angiostrongylus vasorum causes severe clinical signs in dogs. The disease is often challenging because infected animals are often presented with clinical signs overlapping those of other diseases.

The present article describes six angiostrongylosis cases (Cases 1-6) that represent key examples of how canine angiostrongylosis may be extremely confounding. The six animals presented clinical signs compatible with canine angiostrongylosis but they were subjected to clinical examinations for other diseases (e.g. dirofilariosis or immune-mediated disorders) before achieving a correct diagnosis.

In Case 1 clinical, radiographic and ultrasound examinations' results resembled a lung neoplasia. Case 2 was a dog with a mixed infection caused by A. vasorum and Dirofilaria immitis. Case 3 was a critically ill dog presented in emergency for an acute onset of dyspnoea caused by lungworm infection. The dog died a few hours after presentation despite support and etiologic therapy. Case 4 was a dog presented for chronic hemorrhages and ecchymoses caused by thrombocytopenia of unknown origin, thought to have an inherited, immune-mediated or infective cause. Case 5 was referred for neurological signs due to a suspected discospondylitis. Case 6 was erroneously diagnosed infected only with D. immitis although the dog was infected only with A. vasorum. A timely administration of an anthelmintic (mostly moxidectin) showed to be effective in treating the infection in those dogs (i.e. Cases 1,2, 4 and 5) that did not suffer with severe lung haemorrhages yet.

Dogs 1-5 were referred in two regions of Italy that are considered non-endemic for A. vasorum. These findings indicate that veterinarians should include angiostrongylosis in the differential diagnosis of cardio-respiratory distress also in non-endemic regions and should perform appropriate diagnostics in the presence of compatible signs even if the clinical picture is atypical.