Two cases of baylisascariasis—raccoon roundworm infection—occurred in unrelated children in Los Angeles County during 2024.
Baylisascariasis is caused by Baylisascaris procyonis, a roundworm parasite that is commonly found in raccoons. While rare, baylisascariasis can result in serious illness in humans (MMWR Morb Mortal Wkly Rep 2025;74[28]:444-449).
2 Pediatric Cases Linked to Raccoon Feces
The initial case occurred in a 14-year-old adolescent who had been diagnosed with autism spectrum disorder and had a history of pica, or ingestion of nonfood items. An investigation identified raccoon feces that had fallen from a communal raccoon defecation site as the likely source of contamination. The patient was treated with albendazole and corticosteroids and made a full recovery.
The second case occurred in a 15-month-old child. No source of exposure was identified. Although the child was also treated with albendazole and corticosteroids, delays in diagnosis and treatment resulted in severe neurologic sequelae.
“[The report] raises awareness about the potential risks associated with exposure to raccoon feces, especially in young children and people with developmental disabilities and pica, and highlights the need for early diagnosis and treatment,” said Aisling M. Vaughan, PhD, an epidemiologist with the Epidemic Intelligence Service of the CDC and the Acute Communicable Disease Control Program of the Los Angeles County Department of Public Health.
“Be vigilant for eosinophilic meningoencephalitis in young children or people with developmental disabilities or pica,” Dr. Vaughan said. “Prompt empiric treatment with albendazole and with corticosteroids may prevent severe complications.”
A Rare Disease—But Prevalence Is Poorly Understood
Although baylisascariasis is rare, with approximately 30 cases reported in the United States to date, the true prevalence of disease is not well understood.
“Further seroprevalence studies could shed light on how common asymptomatic or mild infections are in the general population, especially in urban and suburban areas,” Dr. Vaughan said.
Dr. Vaughan reported no relevant financial disclosures.
