1431. Occurrence of Sporadic Human Ascariasis in Non-Endemic Regions: The Importance of Zoonotic Transmission from Swine

BACKGROUND: Ascariasis in developed countries occurs only sporadically, and usually in travelers or in children in rural settings with exposure to Ascaris suum from swine. Reciprocal transmission between humans and swine is possible given A. suum and A. lumbricoides are considered conspecific based on published mtDNA and nuclear ribosomal ITS-1 studies with recognized phenotypic/genotypic differences reflecting host-specific adaptive changes. Here we evaluated 15 cases of human ascariasis detected over 6 a year period in a non-endemic region of the Upper Midwest USA. METHODS: Helminth specimens (n=15) spontaneously passed per rectum were submitted for laboratory identification during 2013-19 and identified morphologically as A. lumbricoides/suum (undifferentiated). All patients attended local clinics and brought specimens in for identification. Clinical records were available for 13 patients. RESULTS: Ages ranged from 14 months to 41 years with 13 cases (87%) occurring in children < =12 years and 2 (13%) >30 years; 9 patients (60%) were female. Thirteen (87%) of the A. lumbricoides/suum specimens were adults and 2 (13%) were juveniles. Individuals with records available either lived on or had visited a farm (5) or hobby farm (2) where pigs were currently or likely historically present; lived at a rural address (4); used animal manure for gardening (1); or lacked discernable farm connections though was active outdoors (1). International travel history was lacking in all cases. One 2-year old child from a rural address had passed 2 worms 6 months apart. All 13 patients were treated with albendazole per guideline without complication. CONCLUSION: Ascariasis attributable to poor sanitation has been largely eradicated from the USA since the early 1980s. Sporadic infections in non-travelers have continued to be recognized and likely represent zoonotic transmission from domesticated swine. While human and pig Ascaris have long been considered distinct species, recently published molecular and cross-transmission experiments point to conspecificity. This case series is a reminder of the zoonotic disease risks posed by swine-origin Ascaris, especially in young children, and reinforces the need for proper herd management and attention to personal hygiene for at-risk individuals. DISCLOSURES: All Authors: No reported disclosures