Baylisascaris procyonis

Epidemiology

• common roundworm found in the small intestine of raccoons in North America, Japan & Germany.
  • infests 68-82% of some raccoon populations
• adult worms may be 15-20 cm in length & 1 cm in width
• humans become infected by ingesting soil or other material contaminated with raccoon feces containing eggs
• young children at greatest risk
• case reports from Chicago & Los Angeles in 2000
  • 2 cases in Los Angeles County 2024
• case report from King County Washington in 2017
• CDC report in 2024:
  • 37 cases of Baylisascaris procyonis infection in North America
    • 33 cases in the U.S., 4 in Canada
    • median age of 1.6 years, 82% were male
    • 18% of cases resulted in death
  • geophagia was mentioned in 55% of cases, 33% with developmental disabilities

Pathology

• response of the paratenic host to the invading larvae involvings walling it off or killing it
• collateral damage to tissue occurs
• severe of fatal encephalitis (neural larva migrans) in birds & mammals, including humans
• visceral larval migrans
• ocular larval migrans

Clinical manifestations

• skin irritations from larvae migrating within the skin
• respiratory discomfort
• hepatomegaly
• fever
• nausea
• encephalomyelitis
  • lethargy
  • incoordination
  • visual impairment
  • severe neurological signs
    • seizures
    • coma
    • death

Laboratory

• microscopic examinaton of affected tissue

Management

• prognosis: poor
• albendazole
  • 20-40 mg/kg/day for 1-4 weeks
  • not larvicidal
  • no effect on migrating larvae
  • used in case report without success
• laser surgery has been successfully performed to kill larvae present in the retina but the damage caused by the migrating larvae is irreversible
• treatment with glucocorticoids is mainly supportive intended to decrease the inflammatory reaction

More general terms

• Baylisascaris