Baylisascaris procyonis

• Nematode found in raccoon feces, known as the raccoon roundworm

Background

Life Cycle

• Direct life cycle involves raccoons (Procyon lotor)
• Indirect life cycle can involve other vertebrates, including humans

Epidemiology

• Eggs can be ingested from soil contaminated by raccoon feces
• The worm can infect a number of vertebrate animals
• Present in North America, Europe, Japan, and possibly South America

Clinical Manifestations

• Spectrum of infectious syndromes, including asymptomatic infection
• Visceral larva migrans, causing eosinophilia and symptoms associated with whichever organs are involved
• Neural larva migrans, which is essentially visceral larva migrans of the brain
• Ocular larva migrans, presenting with vision loss
• Diffuse unilateral subacute neuroretinitis

Management

• Ocular larva migrans: laser therapy ± concurrent albendazole
• Neurological larva migrans: albendazole and praziquantel for a long duration, ± corticosteroids
  • Poor outcomes

Further Reading

• Update on Baylisascariasis, a Highly Pathogenic Zoonotic Infection. Clin Microbiol Rev/ 2-16;29(2):375-399. doi: 10.1128/CMR.00044-15