The Mississippi State Department of Health conducted field visits to the patient’s home, but the family’s pigs had been sent to slaughter. The family has 2 flush toilets in their home used for all defecation and disposal of feces. The Mississippi State Department of Health counselled all family members on handwashing, especially after contact with soil where pigs had defecated.

This case represents an autochthonous acquisition of ascariasis in the southeast United States. Only 1 worm was expelled by the patient, even after treatment, and the absence of eggs when treatment occurred suggests that this patient harbored a single adult worm infection. The lifespan of adult A. lumbricoides worms within human hosts is up to 2 years, and eggs may remain viable in soil for up to 10 years (10). The patient’s family had been living in the United States for 13 years, and no promiscuous defecation was occurring in the child’s environment. However, the child lived near domestic pigs, which is a common zoonotic origin for this infection.

Ascariasis is often asymptomatic or subclinical, although abdominal pain, distension, and wasting may occur (7–10). Adult worms migrating in the intestinal tract may obstruct the bile or pancreatic ducts, leading to cholecystitis or pancreatitis (10). Occasionally, migrating adult worms may be expelled through the rectum or emerge from the nose or mouth. In patients with heavy worm infections, bowel obstruction, intussusception, volvulus, and small bowel perforation may occur (10). Heavy infections may also cause malabsorption and stunting with consequent vitamin deficiencies, growth retardation, altered immunity, and impaired cognition (7,10). A larva migrans syndrome may be observed, caused by immune-mediated responses to the visceral migration of A. lumbricoides worm larvae through the lungs and appearing as Löffler syndrome (9).

Confusion exists over the taxonomic status of Ascaris helminths in pigs and humans. The genus Ascaris was once split into 2 species, A. suum and A. lumbricoides, but modern genotyping methods have determined that the 2 categories are instead separate genotypes of the same species, A. lumbricoides (7). Genotypic surveillance of adult A. lumbricoides worms from farmed pigs in Iowa found 10 haplotypes present, including those belonging to A. lumbricoides (human), A. suum (pig), and hybrid genotypes (7).

In summary, we describe a case of likely zoonotic autochthonous human ascariasis acquired in rural northern Mississippi. Sporadic ascariasis cases in the United States are most often zoonotic in origin, with exposure to pigs, or soil contaminated with pig feces, as the primary risk factor.