Table 2.

Major risk factors for helminth infections include poverty and underlying health conditions; however, the demographic risk factors differ between helminths. A summary table of common statistically significant associations is presented. As most cases of STH in the USA occur in immigrant populations and travelers returning from endemic areas, foreign-born persons and travel have not been included in this table for individual infections

Intestinal parasite	Associated risk factors	Regions of USA	References
Ascaris lumbricoides, A. suum (roundworm)	Poverty, children, lacking sanitation & hygiene	Southern states, southeast, Appalachia	[22, 26, 44]
Ancylostoma duodenale, Necator americanus (hookworm)	Extreme poverty, children, lacking sanitation & hygiene	Southern United States	[2, 24]
Trichuris trichiura (whipworm)	Poverty, children, lacking sanitation & hygiene	Southeast, Appalachia	[24, 26]
Strongyloides stercoralis	Caucasian ethnicity, poverty, immunocompromised, HIV comorbidity, alcoholism, male sex	Appalachia	[26, 31], [11]
Toxocara canis, T. cati	Black ethnicity, poverty, male sex, lead ingestion, pet ownership, low educational attainment, cognitive impairment, elevated lead concentration, pica, nutritional status, immunocompromised	Southern states, Appalachia, inner cities	[6, 26, 32, 33, 39, 42, 50–52]