Ascariasis is a common infection in tropical and subtropical regions; 730 million to 804 million people are estimated to be infected worldwide.[3]Jourdan PM, Lamberton PHL, Fenwick A, et al. Soil-transmitted helminth infections. Lancet. 2018 Jan 20;391(10117):252-65.
http://www.ncbi.nlm.nih.gov/pubmed/28882382?tool=bestpractice.com
[4]Holland C, Sepidarkish M, Deslyper G, et al. Global prevalence of Ascaris infection in humans (2010-2021): a systematic review and meta-analysis. Infect Dis Poverty. 2022 Nov 18;11(1):113.
https://www.doi.org/10.1186/s40249-022-01038-z
http://www.ncbi.nlm.nih.gov/pubmed/36401308?tool=bestpractice.com
Within this global cohort, many are at risk for severe, sometimes life threatening complications.[3]Jourdan PM, Lamberton PHL, Fenwick A, et al. Soil-transmitted helminth infections. Lancet. 2018 Jan 20;391(10117):252-65.
http://www.ncbi.nlm.nih.gov/pubmed/28882382?tool=bestpractice.com
[10]de Silva NR, Chan MS, Bundy DA. Morbidity and mortality due to ascariasis: re-estimation and sensitivity analysis of global numbers at risk. Trop Med Int Health. 1997;2:519-28.
http://www.ncbi.nlm.nih.gov/pubmed/9236818?tool=bestpractice.com
[11]de Silva NR, Guyatt HL, Bundy DA. Morbidity and mortality due to Ascaris-induced intestinal obstruction. Trans R Soc Trop Med Hyg. 1997;91:31-36.
http://www.ncbi.nlm.nih.gov/pubmed/9093623?tool=bestpractice.com
In economically developed countries, ascariasis is primarily found in recent immigrants and children adopted from endemic countries.
Clay-containing soils favor the survival and dissemination of Ascaris eggs after rainfall. Eggs can also withstand freezing; therefore, the infection extends into northern temperate zones. Only cold, arid climates seem free of infection. Sanitation, socioeconomic status, and access to health care are additional factors that influence the likelihood of infection within a given population.[12]World Health Organization. Soil-transmitted helminthiasis. Jan 2023 [internet publication].
https://www.who.int/news-room/fact-sheets/detail/soil-transmitted-helminth-infections
Heavy worm burdens are more common in children than adults.[1]Diemert DJ. Ascariasis. In: Guerrant RL, Walker DH, Weller PF, eds. Tropical infectious diseases: principles, pathogens and practice. 3rd ed. Edinburgh: W.B. Saunders; 2011:794-8.[13]Cooper PJ. Interactions between helminth parasites and allergy. Curr Opin Allergy Clin Immunol. 2009;9:29-37.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2680069
http://www.ncbi.nlm.nih.gov/pubmed/19106698?tool=bestpractice.com
In preschool-age children, exposure to subsistence agriculture has been associated with higher intensity infections.[14]Krause RJ, Koski KG, Pons E, et al. Ascaris and hookworm transmission in preschool children in rural Panama: role of subsistence agricultural activities. Parasitology. 2016;22:1-12.
http://www.ncbi.nlm.nih.gov/pubmed/27000494?tool=bestpractice.com