Raccoon Roundworm Infections

Key Features

• Eosinophilic meningoencephalitis or encephalopathy

• Ocular larva migrans

• Human infections with Baylisascaris procyonis, the raccoon roundworm, are increasingly recognized, particularly in children

• Young age, pica, and exposure to raccoon feces represent the main risk factors

Clinical Findings

• Most are asymptomatic

• Severe encephalitis (neural larva migrans) and endophthalmitis (ocular larva migrans) occur

• Symptoms typically begin 2–4 weeks after inoculation

• CNS infections characteristically present as acute, rapidly progressive encephalitis with eosinophilic pleocytosis of the CSF (varies from 4% to 68% eosinophils in mild pleocytosis)

Diagnosis

• Observation of larvae on examination of tissue biopsies or by serology (of serum or CSF)

Treatment

• Antihelminthic drugs have not been shown to have any beneficial effect

• Nevertheless, albendazole (20–40 mg/kg/d for 1–4 weeks) has been used to treat most cases, together with anti-inflammatory drugs

• Complete resolution of symptoms has not been achieved thus far

• Immediate prophylactic treatment with albendazole (25 mg/kg daily for 20 days) should be considered for those with known ingestion of raccoon feces