Roundworms, or nematodes, are parasites that can infect humans, usually by
residing in the intestines. Several different species of worm can cause
infection, and worms can range in length from 1 millimeter to 1 meter. As with
other parasitic diseases, roundworm infections are more common in warm, tropical
climates than in cooler, temperate areas of the world. The most common roundworm
infection is Ascariasis (caused by the worm Ascaris lumbricoides), which
affects as many as 1 billion people worldwide.
Signs and Symptoms
The signs and symptoms of roundworm infection include:
Passage of worm by mouth, rectum, or, with certain species
(particularly dracun culosis), through skin ulcers; worm eggs may also be passed
Loss of appetite
Diarrhea or constipation
Cough, chest pain, or difficultly breathing
Nausea and vomiting
Skin lesions, rashes, hives, itching
Swelling of lymph nodes
Visual impairment with certain species (particularly
According to the National Institute of Allergy and Infectious Diseases, many
roundworm parasitic diseases result from a lack of appropriate personal hygiene
and sanitation measures. Most roundworms or their eggs are found in the soil and
can be picked up on the hands and transferred to the mouth or can enter through
the skin. Different species of roundworms cause different infections.
The various roundworm infections include:
Ascariasis is an infection caused by the roundworm Ascaris
lumbricoides. Infection occurs when an individual consumes food or drink
contaminated with fecal matter that contains mature worm eggs. Adult worms can
reside in the small intestine and produce eggs for a year or more.
A whipworm infection occurs when an individual consumes food or drink
contaminated with fecal matter containing the roundworm Trichuris
trichiura. After eggs are ingested, larvae hatch in the small intestine and
mature in the large intestine.
A hookworm infection occurs when larvae of the roundworms Ancylostoma
duodenale or Necator americanus penetrate human skin, making their
way through the lungs to the small intestine, where they attach and mature into
adults, laying more eggs. Children are particularly susceptible to this kind of
infection. Once infected, children become weak and experience delayed growth
patterns. These roundworms infect about 25% of the world's
Threadworm is an infection caused by the roundworm Strongyloides
stercorali. This type of roundworm infects humans in the same way as
Ancylostoma duodenale. About half of the population of some African
countries has been infected with Strongyloides stercorali.
A pinworm infection occurs when an individual consumes food or drink
contaminated with fecal matter containing the roundworm Enterobius
vermicularis. After being ingested, eggs hatch in the small intestine and
adult worms ultimately inhabit the large intestine. The pregnant female worms
migrate to the anus and deposit large numbers of eggs in the skin around that
area. Pinworm, which is commonly spread in day care centers, schools, and camps,
affects as many as one-third of all American children.
Visceral larva migrans, or VLM
VLM is an infection caused by the roundworms Toxocara canis,
Toxocara cati, or Baylisascaris procyonis. These parasites
ordinarily infect dogs, cats, and raccoons, respectively, but a human can become
infected by consuming soil contaminated by infected animal feces. While the
larvae do not mature to adults in humans, they penetrate the intestinal wall and
migrate to various parts of the body, particularly the lungs and
Trichinosis an infection caused by the roundworm Trichinella spiralis.
These larvae live in pigs and other wild carnivores, such as bears, but humans
can become infected with Trichinella spiralis when they eat such meat
(particularly pork) that is undercooked. The larvae mature in small intestines
and migrate to muscle cells where they can live for months or years.
Guinea worm disease (dracunculosis)
Humans can become infected with Guinea worm disease when they consume
drinking water contaminated with the roundworm Dracunculus medinensis.
Larvae penetrate the intestinal wall, where they mature and migrate to
connective tissues. This type of roundworm infects 10 to 40 million people
annually worldwide, primarily in the Indian subcontinent, West and Central
Africa, and some Middle Eastern countries.
A lymphatic filariasis infection occurs when an individual is bitten by a
mosquito containing the roundworms Wucheria bancrofti, Brugia
malayi, or Brugia timori. Over a period of 6 to 12 months, adult
worms mature and live in human lymph vessels and nodes and can eventually
circulate through the blood. About 90 million people worldwide have been
infected with these roundworms.
River blindness is an infection caused by the roundworm Onchocerca
volvulus. Onchocerciasis, which is spread by day-biting flies, is the
leading cause of blindness worldwide, affecting about 20 million people, mostly
Loiasis is an infection caused by the roundworm Loa loa. Like river
blindness, loiasis is spread by day-biting flies. An estimated 3 to 13 million
people in equatorial Africa have been infected with Loa loa.
The risk factors for roundworm infection include:
Living in or visiting a warm, tropical climate
Poor personal hygiene
Crowded conditions, such as day care or institutional
Frequent practice of anal intercourse
Compromised immune system
Eating undercooked meat from carnivorous animals
Eating dirt or clay (children and especially boys tend to become
infected this way)
Contact with animal feces
Multiple insect bites
Diagnosing roundworm infection involves identifying the species of worm
causing the infection. If a worm passes through the mouth or rectum, it should
be brought to the physician for analysis and identification. Other steps in
diagnosis may include:
Stool and urine samples - identify
microorganisms in the stool and urine
Blood tests - detect infection in the blood
Muscle and/or skin biopsy - reveals
infections that affect the muscle and/or skin
Ultrasound - reveals worms in lymph
X ray - reveals large worms in abdominal
Sampling of contents of small intestine may reveal presence of
Tape test - used particularly for pinworm
infections; physician applies cellulose acetate tape to the skin around the anal
region, removes the tape, and then examines it for pinworm under a
Probably the best solution to the problem of roundworms rests in preventing
these infections rather than in curing them. The steps to preventing roundworm
Good personal hygiene (such as washing hands and avoiding contact with
Avoid uncooked or unwashed fruits and vegetables in areas where
sanitation is poor
Avoid mosquito or fly-infested areas, unfiltered water, and direct
skin contact with soil in areas where roundworm infections are
Wear protective clothing and use insect repellant
Cook or freeze meat thoroughly
Keep children away from pet feces
Consult a veterinarian about deworming pets
Public health measures in areas where roundworm infections are
prevalent include improving general sanitation, especially sewage disposal, and
reducing mosquito and fly populations
The use of antiparasitic
medications is the primary therapy for
roundworm infections; the medication prescribed depends on the specific
Surgical procedures may be necessary under
certain circumstances; such procedures are not always readily available,
however, in areas where roundworm infections are prevalent. Roundworm infections
can inflame the lining of the gut and limit the absorption of and/or compete
with many essential
nutrients, including vitamins A and
B6. Vitamin A deficiencies are believed to increase the risk of parasitic
infections, so some researchers speculate that vitamin A supplementation may
help prevent or reduce symptoms associated with roundworm infections. In
herbal remedies, particularly fig, have been
shown to limit roundworm egg production or destroy roundworms altogether. Some
other studies suggest that
Traditional Chinese Medicine may
prove more effective than placebo in improving the symptoms of roundworm
Antiparasitic drugs and other medications used to treat roundworm infections
and certain complications include:
Mebendazole - for ascariasis, whipworm,
hookworm, and pinworm
Albendazole - for ascariasis, whipworm, and
Thiabendazole - for threadworm
Pyrantel pamoate - for ascariasis, hookworm,
Prednisone - for severe VLM and at certain
times in cases of trichinosis
Diethylcarbamazine (DEC) - for lymphatic
Ivermectin - for river blindness; may also be
effective for threadworm
Oral iron - if anemia is present
Analgesics, anti-inflammatories, antihistamines, and antibiotics
- for relief of symptoms or to treat bacterial
Warnings and Precautions for certain
medications that an individual with roundworm infection should
Surgery and Other Procedures
Surgical removal of worms from Guinea worm disease and river blindness are
possible but are usually not available in many areas where roundworm infection
is prevalent. Surgery may be necessary in some cases when the infection causes
obstructions in the intestines or other organs. To alleviate soft tissue
swelling from lymphatic filariasis, measures such as bandaging, physical
therapy, careful skin care, as well as drainage of excess fluids may be taken.
Nutrition and Dietary Supplements
Malnutrition is associated with roundworm infection, so maintaining optimal
nutritional status may be helpful in preventing and treating roundworm
infection. The following nutrients may be particularly useful in this
Some studies have suggested that vitamin A deficiency may be associated with
roundworm infection. Parasites may deplete stores of vitamin A, leaving the
infected individual with inadequate levels to fight off infection. Parasites may
also impair an individual's ability to absorb fat, thereby interfering with the
intestinal absorption of fat-soluble vitamins such as vitamin A. At this time,
however, there is not enough scientific evidence to suggest that vitamin A
supplementation is effective at preventing or treating malnutrition associated
with roundworm infection.
Vitamin B6 (Pyridoxine)
Animal studies have suggested that vitamin B6-deficient rats recover from
trichinosis significantly slower than rats with normal vitamin B6 status. No
studies have investigated whether vitamin B6 is effective at preventing or
treating roundworm infection in humans, however.
Some herbal remedies have properties that are destructive to parasites such
as roundworm. While many of these herbal remedies have been used traditionally
by certain cultures, few have been scientifically tested for their safety and
effectiveness. These herbal remedies include:
Fig (Ficus glabrata)
Studies of individuals with roundworm infections, including ascariasis,
threadworm, whipworm, and hookworm, have suggested that daily doses of Ficus
glabrata (an extract from a species of fig tree) may reduce roundworm egg
production by up to 85 percent.
Andrographis root (Andrographis paniculata)
Animal studies indicate that this herb may reduce the presence of Wucheria
bancrofti, Brugia malayi, or Brugia timori (lymphatic
filariasis infections) by 84% to 93% in infected dogs. The safety and
effectiveness of this herb has yet to be investigated in humans, however.
Garlic (Allium sativum)
Laboratory studies suggest that large quantities of fresh, raw garlic may
have antiparasitic properties against the roundworm, Ascaris
lumbricoides; this herbal remedy has not yet been tested clinically in
Wormseed (Chenopodium ambrosioides)
Although wormseed has not gone through rigorous scientific testing, this herb
is used throughout the world as an effective antiparasitic agent against
hookworm and whipworm.
Wormwood (Artemisia absinthium)
Various species of wormwood are reported to have antiparasitic properties and
have been used traditionally to treat parasites. The safety and efficacy of this
herb, however, has not been established in clinical trials.
Turmeric (Curcuma longa)
Laboratory studies suggest that curcuminoids, the active components of
turmeric, may work together with wormwood to reduce the destructive activity of
parasites. Clinical trials with humans are warranted.
Rangoon creeper (Quisqualis indica)
The seeds of this tropical vine are frequently used throughout Southeast Asia
for treating infections associated with roundworms, particularly ascariasis and
pinworm. Results of clinical studies suggest that this herb may eliminate
between 30% and 86% of roundworms in infected individuals.
Other herbs with a substantial history of treating roundworms include pumpkin
seeds and husks (Curcubita pepo), Punica granatum (Pomegranate
bark), and quassia (Picraena excelsa). The clinical safety and
effectiveness of these herbs have not been scientifically studied,
Traditional Chinese Medicine
One randomized, controlled study of 92 individuals infected with the
roundworm Ascaris lumbricoides demonstrated that people treated with
acupuncture combined with traditional Chinese herbs had significantly greater
improvement in symptoms compared with people who were treated with conventional
Most antiparasitic drugs used to treat roundworm infection should not be used
Warnings and Precautions
Ivermectin - this medication, sometimes used
to treat roundworm infections, should not be given to nursing mothers, the
severely ill, children under 5 years old, or those weighing less than 15 kg (6.8
Antioxidant supplements - some antioxidant
supplements, such as selenium and vitamins C and E, should be avoided during the
treatment of roundworms. In theory, these antioxidants may enhance the activity
of roundworms. In one study, the effectiveness of the medication, mebendazole,
appeared to be diminished when these supplements were taken at the same
Prognosis and Complications
There are several possible complications associated with roundworm
infections. They include:
Intestinal obstruction (caused by the roundworm itself)
Inflammation of the intestines or gall bladder
Pus accumulation in the liver
Inflammation of the pancreas
Peritonitis (inflammation of the sac surrounding the abdomen;
generally with fluid accumulation)
Encephalopathy (disorder of the brain)
Cardiomyopathy (disease of the cardiac muscle of the heart)
Distorted, abnormal growth of the skin and surrounding soft
Blindness (from onchocerciasis)
The course of some roundworm infections can be long and unpleasant, and there
are many possible complications. Individuals living in areas where roundworm
infections are prevalent may become infected more than once. Fortunately, most
roundworm infections can be successfully treated with antiparasitic medications.
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Review Date: March 2001
Reviewed By: Participants in the review process include: Richard Glickman-Simon, MD,
Department of Family Medicine, New England Medical Center, Tufts University,
Boston, MA; Jacqueline A. Hart, MD, Department of Internal Medicine,
Newton-Wellesley Hospital, Harvard University and Senior Medical Editor
Integrative Medicine, Boston, MA; Joseph Lamb, MD, The Integrative Medicine
Works, Alexandria, VA; David Winston, Herbalist, Herbalist and Alchemist, Inc.,
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