An adult female Ascaris worm.Adult worms (1) live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces (2). Unfertilized eggs may be ingested but are not infective. Fertile eggs embryonate and become infective after 18 days to several weeks (3), depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed (4), the larvae hatch (5), invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs (6) (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed (7). Upon reaching the small intestine, they develop into adult worms (8). Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.
Find information on thousands of medical conditions and prescription drugs.


Ascariasis is a debilitating human disease caused by the roundworm Ascaris lumbricoides; other species of Ascaris are parasitic in domestic animals (see Nematode). Perhaps as many as one quarter of the world's people are infected, but ascariasis is particularly prevalent in tropical regions and in areas of poor hygiene. more...

Aagenaes syndrome
Aarskog Ose Pande syndrome
Aarskog syndrome
Aase Smith syndrome
Aase syndrome
ABCD syndrome
Abdallat Davis Farrage...
Abdominal aortic aneurysm
Abdominal cystic...
Abdominal defects
Absence of Gluteal muscle
Accessory pancreas
Achard syndrome
Achard-Thiers syndrome
Achondrogenesis type 1A
Achondrogenesis type 1B
Achondroplastic dwarfism
Acid maltase deficiency
Ackerman syndrome
Acne rosacea
Acoustic neuroma
Acquired ichthyosis
Acquired syphilis
Acrofacial dysostosis,...
Activated protein C...
Acute febrile...
Acute intermittent porphyria
Acute lymphoblastic leukemia
Acute lymphocytic leukemia
Acute mountain sickness
Acute myelocytic leukemia
Acute myelogenous leukemia
Acute necrotizing...
Acute promyelocytic leukemia
Acute renal failure
Acute respiratory...
Acute tubular necrosis
Adams Nance syndrome
Adams-Oliver syndrome
Addison's disease
Adducted thumb syndrome...
Adenoid cystic carcinoma
Adenosine deaminase...
Adenosine monophosphate...
Adie syndrome
Adrenal incidentaloma
Adrenal insufficiency
Adrenocortical carcinoma
Adrenogenital syndrome
Aicardi syndrome
AIDS Dementia Complex
Albright's hereditary...
Alcohol fetopathy
Alcoholic hepatitis
Alcoholic liver cirrhosis
Alexander disease
Alien hand syndrome
Alopecia areata
Alopecia totalis
Alopecia universalis
Alpers disease
Alpha 1-antitrypsin...
Alport syndrome
Alternating hemiplegia
Alzheimer's disease
Ambras syndrome
Amelogenesis imperfecta
American trypanosomiasis
Amyotrophic lateral...
Androgen insensitivity...
Anemia, Diamond-Blackfan
Anemia, Pernicious
Anemia, Sideroblastic
Aneurysm of sinus of...
Angelman syndrome
Ankylosing spondylitis
Annular pancreas
Anorexia nervosa
Anthrax disease
Antiphospholipid syndrome
Antisocial personality...
Antithrombin deficiency,...
Anton's syndrome
Aortic aneurysm
Aortic coarctation
Aortic dissection
Aortic valve stenosis
Apert syndrome
Aphthous stomatitis
Aplastic anemia
Argininosuccinic aciduria
Arnold-Chiari malformation
Arrhythmogenic right...
Arteriovenous malformation
Arthritis, Juvenile
Arthrogryposis multiplex...
Aseptic meningitis
Asherman's syndrome
Asphyxia neonatorum
Ataxia telangiectasia
Atelosteogenesis, type II
Atopic Dermatitis
Atrial septal defect
Atrioventricular septal...
Attention Deficit...
Autoimmune hepatitis
Autonomic dysfunction
Familial Alzheimer disease

Infection occurs through ingestion of food contaminated with fecal matter containing Ascaris eggs. The larvae hatch, burrow through the intestine, reach the lungs, and finally migrate up the respiratory tract. From there they are then reswallowed and mature in the intestine, growing up to 30 cm (12 in.) in length and anchoring themselves to the intestinal wall.

Infections are usually accompanied by inflammation, fever, and diarrhea, and serious problems may develop if the worms migrate to other parts of the body.


Roughly 1.5 billion individuals are infected with this worm1. Ascariasis is endemic in the United States including Gulf Coast and Ozark Mountains; in Nigeria and in Southeast Asia. One study indicated that the prevalence of ascariasis in the United States at about 4 million (2%). In a survey of a rural Nova Scotia community, 28.1% of 431 individuals tested were positive for Ascaris, all of them being under age 20, while all 276 tested in metropolitan Halifax were negative2.

Deposition of ova (eggs) in sewage hints at the degree of ascariasis incidence. A 1978 study showed about 75% of all sewage sludge samples sampled in United States urban catchments contained Ascaris ova, with rates as high as 5 to 100 eggs per liter. In Frankfort, Indiana, 87.5% of the sludge samples were positive with Ascaris, Toxocara, Trichuris, and hookworm. In Macon, Georgia, one of the 13 soil samples tested positive for Ascaris. Municipal wastewater in Riyadh, Saudi Arabia detected over 100 eggs per liter of wastewater 3 and in Czechoslovakia was as high as 240-1050 eggs per liter 4.

Ascariasis sources can often be measured by examining food for ova. In one field study in Marrakech, Morocco, where raw sewage is used to fertilize crop fields, Ascaris eggs were detected at the rate of 0.18 eggs/kg in potatoes, 0.27 eggs/kg in turnip, 4.63 eggs/kg in mint, 0.7 eggs/kg in carrots, and 1.64 eggs/kg in radish5. A similar study in the same area showed that 73% of children working on these farms were infected with helminths, particularly Ascaris, probably as a result of exposure to the raw sewage.

Life cycle

First appearance of eggs in stools is 60-70 days. In larval ascariasis, symptoms occur 4-16 days after infection. The final symptoms are gastrointestinal discomfort, colic and vomiting, fever; observation of live worms in stools. Some patients may have pulmonary symptoms or neurological disorders during migration of the larvae. However there are generally few or no symptoms. A bolus of worms may obstruct the intestine; migrating larvae may cause pneumonitis and eosinophilia.


[List your site here Free!]

Women, water management, and health
From Emerging Infectious Diseases, 11/1/04 by Susan Watts

Women play a major role in domestic water management in areas where safe water and drainage are not available in the house. In these settings, women are typically responsible for collecting, storing, and using water and for disposing of wastewater (1,2). Most studies of women's water management and the health benefits of safe water and sanitation examine the effect of protected water sources, such as covered wells or pumps, and basic sanitation (3). However, water management may also be a health issue in large villages and periurban communities that are supplied with piped water but have inadequate sanitation or drainage facilities. For example, in Egypt's Nile Delta, tap water is available in most rural communities (although not in every house), and no absolute shortage of water exists. However, safely disposing of wastewater and toilet effluent often remains a problem; this problem is exacerbated by the high water table associated with the irrigation system.

We conducted a study on Schistosoma mansoni in two Nile Delta villages (each with a population of [approximately equal to] 8,000) from 1991 to 1998. During this period, villagers risked infection with S. mansoni when they came into contact with water in irrigation canals; women were especially at risk when washing laundry and utensils in the canal.

In our 1992 survey, both study villages had access to piped water; 78% of households in al-Garda and 39% in al-Salamuniya had household connections. Al-Garda village had a pipeborne sewage system, but only one third of households were connected to it. Although 98% of households in al-Garda and 94% in al-Salamuniya had toilets, many of those households not connected to the sewage system did not safely dispose of effluent. In some cases, effluent in sewage vaults contaminated the subsoil water, and 25% of the toilets in al-Garda and 65% of these in al-Salamuniya had to be emptied periodically, usually with a bucket. A few toilets in both villages illegally emptied directly into a canal or drain. Unsafe disposal of latrine effluent was implicated in schistosomiasis transmission.

Examining water management in these two villages, we asked what choices women had and why they made decisions that continued to expose them to the risk for schistosomiasis. They found that advice to "Keep away from the canal!" was not relevant to their situation. A number of factors influenced women's water management choices, and hence, their use of the canal: effort involved, water quality and cost, and an appreciation of the opportunity for social interaction with relatives and neighbors.

Women washed domestic utensils and clothes at the canal because it saved them time and effort. If they had no household connection, they had to carry water into the house from a public standpipe. Even in households with an inside tap, women often stored water in case the supply was interrupted. For most women, those who lived in houses without a drainage system, the biggest problem was that all water used in the house had to be carried outside and thrown into the street or canal.

Water quality was also an issue. Women recognized that water from the piped (subsurface) supply was "hard" compared to canal water; in al-Garda, water hardness in the canal measured 210-280 rag/L, compared to 450 mg/L for water from the piped system. Washing at the canal used less soap, and laundry and utensils looked cleaner than if they were washed at home.

A few women said that they used the canal because of the increased cost of water. In the early 1990s, the national water authority was phasing out public standpipes, installing metered connections to every household, and charging for water according to the amount used, rather than a flat rate. Within a few months, the cost of water per cubic meter had risen 250% (4).

Our study suggests that the potential health benefit of piped water supplied to each house is limited if no way to remove wastewater exists. Under recent "cost recovery" policies, poor families may not be able to pay the bills for water, drainage, and sanitation; nor can they pay the full costs required to link up to such systems. Less expensive alternatives are essential; otherwise many households will go without safe drainage and sanitation.

The recent article by Clasen and Cairncross (5) indicates that water management is a high-profile health issue. The authors focus their discussion of the effect of water management on diarrheal diseases. Globally, these kill an estimated 2.5 million people a year, largely among children younger than 5 years (diarrheal diseases are the second most important cause of death among infants in Egypt). The authors do not directly identify water management as a gender issue, but they do point out that epidemiologic studies rarely look at water quality at the point of use. The process of storing and using household water has considerable risk for microbial contamination, even if the water comes from treated, piped sources, and is usually a woman's responsibility (6).

In Egypt, as in poor countries throughout the world, the availability of safe sanitation, especially in rural areas, lags behind that of safe water (7). Epidemiologic studies have indicated that safe sanitation may be even more important than safe water to reduce diarrhea death rates (3). As a health issue, then, safe water and safe sanitation are indissolubly linked.

Three hygiene-related behaviors protect infants against diarrhea: washing hands before preparing food and after using the toilet, safely disposing of infant feces, and safely storing water in the house (5). In Egypt and elsewhere, we need to identify constraints facing rural women that prevent them from adopting these protective behaviors. Identifying barriers to women's adopting certain hygiene, water, and sanitation behaviors could also be important for other health concerns, such as trachoma, recently recognized as resurgent in rural Egypt (8).

These examples suggest that in planning effective control strategies for diseases associated with a lack of safe water and sanitation, we need a greater understanding of women's water management and hygiene behaviors and local constraints they experience. We need to incorporate this knowledge into health promotion, including behavior change. Another issue is women's empowerment, strengthening their ability to make their concerns heard within the community and beyond. Expecting women to change their behavior is unrealistic unless water quality and, especially, drainage and sanitation are upgraded. Policy for safe water and sanitation needs to ensure that water is regularly accessible and safe at the point of use and that sewage and wastewater can be disposed of safely. Above all, a commitment is needed from national governments to provide and maintain safe and affordable water and sanitation for all citizens.


The author acknowledges the intellectual support of Samiha El Katsha over many years of work in Egypt.

The research project in the Nile Delta was funded by the Schistosomiasis Research Project, under research agreement #04-05-38, and conducted under the auspices of the Social Research Center at the American University in Cairo. Coprincipal investigators were Samiha El Katsha and Susan Watts. Human subjects approval was granted by the American University in Cairo.


(l.) Roark PD. Women and water. In: Bourne PG, editor. Water and sanitation: economic and sociological perspectives. Orlando (FL): Academic Press; 1984.

(2.) El Katsha S, White AU. Women, water, and sanitation: household behavioral patterns in two Egyptian villages. Water International. 1989;14:103-11.

(3.) Esry SA, Potash JB, Roberts L, Shift C. Effects of improved water supply and sanitation on ascariasis, diarrhoea, dracunculiasis, hook-worm infection, schistosomiasis, and trachoma. Bull World Health Organ. 1991;69:609-21.

(4.) El Katsha S, Watts S. Gender, behavior and health: schistosomiasis transmission and control in rural Egypt. Cairo and New York: American University in Cairo Press; 2003.

(5.) Clasen TF, Cairncross S. Household water management: refining the dominant paradigm. Trop Med Int Health. 2004;9:187-91.

(6.) Jensen PK, Ensink JH, Jayasinghe G, van der Hoek W, Cairncross S, Dalsgaard A. Domestic transmission routes of pathogens: the problem of in-house contamination of drinking water during storage in developing countries. Trop Med Int Health. 2002;7:640-9.

(7.) El-Zanaty F, Way AA. Egyptian interim demographic and health survey, 2003. Cairo: Ministry of Health and Population [Egypt], National Population Council, El-Zanaty and Associates and ORC Macro; 2003. p. 8.

(8.) Al Arab GE, Tawfik N, El Gendy R, Anwar R, Courtright P. The burden of trachoma in the rural Nile Delta of Egypt: a survey of Menofiya governorate. Br J Ophthalmol. 2001;85:1406-10.

Dr. Watts is a senior research associate at the Social Research Center, American University in Cairo. Her main research interest in human behavior and the transmission of water-related diseases. In addition to studying schistosomiasis in Egypt, she has conducted research on dracunculiasis in Nigeria.

Address for correspondence: Susan Watts, Social Research Center, American University in Cairo, PO Box 2511, 11511 Cairo, Egypt; fax: 202-795-7298; email:

Susan Watts, American University in Cairo, Cairo, Egypt

COPYRIGHT 2004 U.S. National Center for Infectious Diseases
COPYRIGHT 2004 Gale Group

Return to Ascariasis
Home Contact Resources Exchange Links ebay