Roundworms, or nematodes, are parasites that can infect people. They usually live in the intestines. There are different kinds of worms that can cause infection, and they can range in length from 1 millimeter to 1 meter.
Most often, eggs, or larvae, live in the soil and get into the body when you get them on your hands and then touch your mouth. Some can also get into the body through the skin.
Like other parasitic diseases, roundworm infections happen more often in warm, tropical climates. Ascariasis is the most common roundworm infection, and affects as many as 1 billion people worldwide.
Signs and Symptoms
The signs and symptoms of roundworm infection include:
- Shortness of breath
- Abdominal pain
- Nausea and diarrhea
- Blood in the stool
- Weight loss
- Presence of the worm in vomit or stool
Guinea worm disease
Symptoms start about one year after infection. When the adult worm is ready to lay eggs, it comes out through the skin. A blister develops, usually on the legs or feet, and becomes an open wound. When that part of your body is submerged in water, the tip of the worm comes out to lay its eggs. Symptoms include pain and swelling at the site of the wound.
Often there are not any symptoms, if there are symptoms they may include:
- Itchy rash
- Trouble breathing
- Abdominal pain
- Weight loss
- Loss of appetite
- Watery or itchy eyes
- Blurred vision
- Some people may see the worm move across the eyes
- Swelling and scarring, especially of the legs and groin
- Itchy rash
- Sores on the skin
- Swollen lymph nodes
- Skin turns white (loss of pigmentation)
- Vision loss
- Itch where the worm enters the skin (similar to a bug bite)
- Nausea and diarrhea
- Blood in the stool
- Dry cough or coughing up blood
- Trouble breathing
- Abdominal pain
- High fever
- Muscle pain
- Sensitivity to light (photosensitivity)
- Pink eye (conjunctivitis)
- Abdominal pain
- Diarrhea (sometimes bloody)
Many roundworm parasitic diseases are caused by poor sanitation and hygiene. Most roundworms or their eggs are found in the dirt and can be picked up on the hands and transferred to the mouth, or they can get into the body through the skin. Different species of roundworms cause different infections.
Roundworm infections include:
- Ascariasis: People become infected when they eat food or drink water that contains the eggs of the roundworm Ascaris lumbricoides. That can happen when people eat food grown in soil that has been mixed with human waste. Once in the body, the larvae go into the lungs and then the throat, where they are coughed up and swallowed. Once they swallowed, they go into the intestines and become adults. They can produce eggs for a year or more.
- Guinea worm disease (dracunculosis): People can become infected with Guinea worm disease when they drink contaminated water. Larvae grow into adults in the intestines, where they can be 3 feet long. Then the adult moves to another area of the body (usually the legs) and comes out through a painful blister. The tip of the worm comes out through the skin to lay its eggs whenever the skin is immersed in water. This type of roundworm infects 10 to 40 million people annually worldwide, mostly in India, West and Central Africa, and some Middle Eastern countries.
- Hookworm (ancylostomiasis): A hookworm infection happens when larvae come into contact with human skin, through contaminated soil or feces. They go through the skin, making their way through the lungs to the small intestine. There they latch on and grow into adults, laying more eggs. They feed off the blood of the infected person, which can cause anemia. Children are especially vulnerable to this kind of infection. These roundworms infect about 25% of the world's population.
- Loiasis: Loiasis is an infection caused by the roundworm Loa loa. Like river blindness, loiasis is spread by day-biting flies. About 3 to 13 million people in equatorial Africa have been infected with Loa loa.
- Lymphatic filariasis: A lymphatic filariasis infection happens when a person is bitten by a mosquito containing the roundworms Wucheria bancrofti, Brugia malayi, or Brugia timori. Over 6 to 12 months, adult worms mature and live in human lymph vessels and nodes. They release eggs that circulate through the blood. About 90 million people worldwide have been infected with these roundworms.
- Pinworm (enterobiasis): A pinworm infection happens when a person consumes food or drink contaminated with feces. The eggs hatch in the small intestine, and adult worms live in the large intestine. The pregnant female worms move to the anus and deposit large numbers of eggs in the skin around that area. Pinworm, which is often spread in day care centers, schools, and camps, affects as many as 1/3 of all American children.
- River blindness (onchocerciasis): River blindness is an eye infection caused by the roundworm Onchocerca volvulus. River blindness is spread by day-biting flies, and is the leading cause of blindness worldwide. It affects about 20 million people, mostly in Africa.
- Threadworm (strongyloidiasis): Threadworm usually happens when someone walks barefoot on contaminated soil, and larvae get into the skin. Inside the body, they move to the lymph nodes and then to the lungs and throat. When the person coughs, the larvae are swallowed and move to the intestines. There they grow into adults and produce eggs. About half of the population of some African countries have been infected with threadworm.
- Trichinosis (trichiniasis): Trichinosis is an infection caused by the roundworm Trichinella spiralis. These larvae live in pigs and other wild carnivores, such as bears. People can get infected when they eat meat (particularly pork) that is undercooked. The larvae mature in the small intestine and move to muscle cells where they can live for months or years.
- Visceral larva migrans, or VLM (toxocariasis): VLM is an infection caused by the roundworms Toxocara canis, Toxocara cati, or Baylisascaris procyonis. These parasites usually infect dogs, cats, and raccoons. People can get infected by eating soil contaminated by animal feces. While the larvae do not grow to be adults in people, they go through the intestinal wall and move to various parts of the body, particularly the lungs and liver.
- Whipworm (trichuriasis): A whipworm infection happens when a person eats food contaminated with soil that has the eggs of the worm. After eggs are eaten, larvae hatch and attach themselves to the large intestine.
The risk factors for roundworm infection include:
- Living in or visiting a warm, tropical climate
- Poor sanitation
- Poor personal hygiene
- Crowded conditions, such as day care or institutional settings
- Weakened immune system
- Eating undercooked meat
- Eating dirt or clay, children tend to become infected this way
- Contact with animal feces
- Multiple insect bites
Diagnosing roundworm infection involves finding out which worm is causing the infection. If you have lived in or visited an area where these parasites are common, your doctor may suspect an infection. If a worm passes through the mouth or rectum, take it to your doctor so it can be identified. Other steps in diagnosis may include:
- Physical exam
- Stool and urine samples: to identify microorganisms in the stool and urine
- Blood tests: to find infection in the blood
- Muscle or skin biopsy: to find infections that affect the muscle or skin
- Ultrasound: reveals worms in lymph nodes
- X-ray: show large worms in abdominal region
- Tape test: used particularly for pinworm infections. A doctor applies sticky tape to the skin around the anus, and then examines the tape under a microscope.
It is easier to prevent roundworms than to cure them. The steps to preventing roundworm infection include:
- Practice good personal hygiene. Wash hands and avoid contact with fecal matter.
- DO NOT eat uncooked or unwashed fruits and vegetables.
- Stay away from mosquito or fly-infested areas.
- DO NOT drink unfiltered water
- DO NOT touch the soil in areas where roundworm infections are common.
- Wear protective clothing and use insect repellant.
- Cook or freeze meat thoroughly.
- Keep children away from pet feces.
- Ask a veterinarian about deworming pets.
- Public health measures include improving general sanitation, especially sewage disposal, and reducing mosquito and fly populations.
The main treatment for roundworm infections are medications that kill parasites. Which medication you take depends on which roundworm is causing the infection. Sometimes a person may need surgery, but it is not always possible in areas where roundworm infections are common.
Roundworm infections can cause inflammation in the intestines and make it hard for your body to absorb essential nutrients, including vitamins A and B6. Some scientists think that not getting enough vitamin A increases the risk of parasitic infections. So some researchers believe that vitamin A supplements may help prevent or reduce symptoms of roundworm infections.
Antiparasitic drugs and other medications used to treat roundworm infections and certain complications include:
- Ascariasis: Medendazole (Vermox), ivermectin (Stromectol), albdendazole (Albenza)
- Hookworm: Medendazole (Vermox), albdendazole (Albenza)
- Loiasis: Dieythelcarbamazine (DEC, Hetrazan), albdendazole (Alvenza)
- Lymphatic filiariasis: Ivermectin (Stromectol), dieythelcarbamazine (DEC, Hetrazan)
- River blindness: Ivermectin (Stromectol)
- Threadworm: Ivermectin (Stromectol), thiabendazole (Mintezol), albdendazole (Albenza)
- Trichinosis: Albdendazole (Albenza), medendazole (Vermox)
- Whipworm: Medendazole (Vermox), albdendazole (Albenza)
- Prednisone: for severe VLM and sometimes in cases of trichinosis
- Oral iron: if the person is anemic
- Pain relievers, anti-inflammatories, antihistamines, and antibiotics: for relief of symptoms or to treat bacterial infection
See "Warnings and Precautions" for certain medications that someone with roundworm infection should avoid.
Surgery and Other Procedures
Guinea worms should be removed surgically, but surgery is not available in many areas where there are a lot of infections. A person may also need surgery if the roundworm infection causes obstructions in the intestines or other organs. Treatment to reduce swelling from lymphatic filariasis may include:
- Physical therapy
- Careful skin care
- Draining fluids
Nutrition and Dietary Supplements
Many people who are infected with roundworms are malnourished, so getting enough nutrients for overall health may help prevent and treat roundworm infection. However, scientists do not know of any supplements that will cure these infections once you have them. If you decide to use complementary and alternative therapies, be sure to tell your health care provider about the herbs and supplements you are using or considering using.
These tips for overall good health may lower chances of getting infected:
- Eat bitter and spicy foods, such as those containing turmeric (curries), cayenne peppers, green chilies, olives, figs, garlic, and ginger.
- Drink warm teas that contain spices such as cardamom, clove, and cinnamon.
- Eat more dark leafy greens (spinach and kale) and sea vegetables.
- Eat antioxidant foods, including fruits (blueberries, cherries, and tomatoes) and vegetables (squash and bell peppers).
- Avoid refined foods, such as white breads, pastas, and especially sugar.
- Eat fewer meats, and more cold-water fish, tofu (soy, if no allergy) or beans for protein. Make sure meat is thoroughly cooked.
- Use healthy oils in foods, such as olive oil or vegetable oil.
- Avoid caffeine, alcohol, and tobacco.
- Drink 6 to 8 glasses of filtered water daily.
- Exercise at least 30 minutes daily, 5 days a week.
- Take a multivitamin daily, containing the antioxidant vitamins A, C, E, the B-complex vitamins, and trace minerals, such as magnesium, calcium, zinc, and selenium.
Herbs can help strengthen and tone the body's systems. As with any therapy, you should work with your provider to diagnose your problem before starting any treatment. You may use herbs as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, you should make teas with 1 tsp. herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Drink 2 to 4 cups per day.
Although there are no scientific studies that show any herbs help treat roundworm infections, the following herbs may help overall health:
- Turmeric (Curcuma longa) standardized extract: 300 mg, 3 times a day, appears to kill parasites in test tube and animal studies. Researchers do not know if it works in people. Turmeric may increase the risk of bleeding. Ask your doctor before taking it if you also take blood thinners such as aspirin or warfarin (Coumadin).
- Garlic (Allium sativum) standardized extract: 400 mg, 2 to 3 times daily, kills parasites in test tubes and animals, but there is no evidence yet whether it works in humans. Garlic may increase the risk of bleeding. Ask your doctor before taking it if you also take blood thinners such as aspirin or warfarin (Coumadin), or if you have an ulcer. Garlic may potentially interfere with certain medications, including birth control medications and drugs used to treat HIV/AIDS.
- Wormwood (Artemisia absinthium), black walnut (Juglans nigra), and clove (Syzygium aromaticum):are often used in combination herbal formulas for parasitic infections. Take as directed by your provider. Be sure to ask your doctor before taking wormwood. Avoid taking these herbs if you have stomach ulcers, kidney disease, or porphyria. Pregnant women should not take wormwood. Wormwood may interact with some antiseizure medications. People who are allergic to ragweed may also have a reaction to wormwood.
Most antiparasitic drugs used to treat roundworm infection should not be used during pregnancy.
Warnings and Precautions
Ivermectin, a 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 lb)
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
- Kidney disease
- Pus accumulation in the liver
- Inflammation of the pancreas
- Peritonitis, inflammation of the sac surrounding the abdomen
- Encephalopathy, a brain disorder
- Cardiomyopathy, a disease of the heart muscle
- Abnormal growth of the skin and surrounding soft tissue
- Blindness (from onchocerciasis)
Some roundworm infections can last a long time, and there are many possible complications. People living in areas where roundworm infections are common may become infected more than once. Fortunately, most roundworm infections can be treated with antiparasitic medications. For example, the prognosis in cases of ascariasis and pinworm is generally excellent.
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Ascariasis; Guinea worm disease; Hookworm; Loiasis; Lymphatic filariasis; Parasitic infection - roundworms; Pinworm; River blindness; Threadworm; Trichinosis; Visceral larva migrans; Whipworm
- Last reviewed on 12/9/2014
- Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.
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