rare ... see also overview of Ascariasis.
Ascariasis is the most common human worm infection. Infection occurs worldwide and is most common in tropical and subtropical areas where sanitation and hygiene are poor. Children are infected more often than adults. In the United States, infection is rare, but most common in rural areas of the southeast. (Source: excerpt from Ascaris Infection: DPD)
16 MEDICAL BOOKS ONLINE! Review excerpts from medical books online, free, without registration, for more information about the prevalence and/or incidence of Ascariasis.
Both forms of hookworm disease are transmitted to humans through direct skin penetration (usually in the foot) by hookworm larvae in soil contaminated with feces containing hookworm ova. These ova develop into infectious larvae in 1 to 3 days. Larvae travel through the lymphatics to the pulmonary capillaries, where they penetrate alveoli and move up the bronchial tree to the trachea and epiglottis, where they're swallowed and enter the GI tract. When they reach the small intestine, they mature, attach to the jejunal mucosa, and suck blood, oxygen, and glucose from the intestinal wall. These mature worms then deposit ova, which are excreted in the stool, starting the cycle anew. Hookworm larvae mature in approximately 5 to 6 weeks.
Hookworm disease, affecting billions of people worldwide, is most common in moist tropical and subtropical regions. There's little risk of aquiring hookworm disease in the United States because of advances in sanitization and waste control.
Source: Professional Guide to Diseases (Eighth Edition), 2005
A. lumbricoides is a large roundworm resembling an earthworm. It's transmitted to humans by ingestion of soil contaminated with human feces that harbor A. lumbricoides ova. Such ingestion may occur directly (by eating contaminated soil) or indirectly (by eating poorly washed raw vegetables grown in contaminated soil).
Ascariasis never passes directly from person to person. After ingestion, A. lumbricoides ova hatch and release larvae, which penetrate the intestinal wall and reach the lungs through the bloodstream. After about 10 days in pulmonary capillaries and alveoli, the larvae migrate to the bronchioles, bronchi, trachea, and epiglottis. There they are swallowed and return to the intestine to mature into worms.
Ascariasis is most common in tropical areas with poor sanitation and in Asia, where farmers use human feces as fertilizer. In the United States, it's more prevalent in the south, particularly among people ages 4 to 12.
Source: Professional Guide to Diseases (Eighth Edition), 2005
~1/4 of the world’s population is infested with this worm.
Source: The 5-Minute Pediatric Consult, 2008
The term 'prevalence' of Ascariasis usually refers to the estimated population of people who are managing Ascariasis at any given time. The term 'incidence' of Ascariasis refers to the annual diagnosis rate, or the number of new cases of Ascariasis diagnosed each year. Hence, these two statistics types can differ: a short-lived disease like flu can have high annual incidence but low prevalence, but a life-long disease like diabetes has a low annual incidence but high prevalence. For more information see about prevalence and incidence statistics.
What do you think about the features of this website? Take our user survey and have your say:
Next articles:
Tools & Services:
Medical Articles:
Search Specialists by State and City
By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.
Copyright © 2009 Health Grades Inc. All rights reserved.
Constant trips to the bathroom, burning, discomfort, we've all experienced diarrhea at one time or another. But why does it occur? Some say...
Diarrhea usually goes away on its own, but in some cases medication and other forms of treatment are necessary. What are the options? Join our panel...
Embarrassing, unpredictable and often uncomfortable, gas is a problem few people like to talk about. But everyone has a little gas now and then. When...
A tiny camera called laparoscope can be used to peek inside the body and diagnose disease. Learn how this minimally invasive technique is now being...