Parasites
Related Terms
Antihelminthic, antimalarials, anti-parasitic, ascariasis, filariasis, guinea worm disease, histoplasmosis, hookworm, hookworm infection, host, leishmania, loiasis, lymphatic filariasis, malaria, parasite, parasitic fungi, river blindness, roundworms, threadworm infection, trichinella, trichinosis, visceral larva migrans, whipworm infection, worms.
Background
A parasite is an organism that lives off of or inside of another organism, called a host, during all or part of its life. This is a type of symbiotic relationship in which the parasite needs the host in order to live. The parasite obtains nourishment and/or protection from its host. A parasite may or may not harm the host, but the host never benefits from the parasite. Many organisms, including some plants, animals, spiders, crustaceans, bacteria, and worms, are considered parasites.
Many parasites can enter the human body and cause parasitic infections. Parasites may enter the body through openings in the body, including the skin and mouth. Each type of parasite affects the human body differently. Some feed on humans cells (such as red blood cells), while others live in the intestines and absorb nutrients from food that is consumed by the host. Parasites can cause many life-threatening complications, including anemia, malnutrition, blindness, and organ and tissue damage.
Among the most common types of parasites to affect humans are single-celled organisms called protozoans, worm-like organisms, fungi, and mites. These organisms are most likely to cause diseases such as ascariasis, chiggers, giardiasis, guinea worm disease, histoplasmosis, hookworm infection, leishmaniasis, lymphatic filariasis, malaria, ringworm infection, scabies, tapeworm infection, river blindness, threadworm infection, trichinosis and whipworm infection. Parasites are responsible for the most deaths in tropical and subtropical regions of the world.
Although parasitic infections can cause permanent tissue and organ damage, most patients experience a complete recovery if they are diagnosed and treated quickly. Parasitic infections are treated with medications, called anti-parasitics. These medications, which may be taken by mouth, applied to the skin, or injected into a vein, kill the parasite.
Signs and symptoms
General: Symptoms vary depending on the type and severity of the infection.
Ascariasis: Symptoms of ascariasis can range from mild to severe, depending on how many parasites are inside the patient's body. If only a few parasites are consumed, patients generally experience few, if any, symptoms.
When the larvae enter the lungs, patients may experience symptoms similar to pneumonia, such as persistent cough, shortness of breath, and wheezing.
When the larvae reach the intestines and develop into adults, mild or moderate symptoms may include abdominal pain, nausea, diarrhea, and sometimes bloody stools. Severe infections may cause abdominal pain, fatigue, vomiting, weight loss, worm in vomit or stools, or worm emerging from the nose or mouth.
Chiggers: After a chigger is fully fed, it will drop off the individual. Three to six hours after a bite, patients develop a red, itchy welt that has a white center. The welt may develop into dermatitis (dry, itchy, flaky skin). Some patients may also experience fever and swelling. Depending on the sensitivity of the patient, symptoms may last for weeks. Patients should not scratch the bite mark because it may break the skin and potentially lead to secondary infections.
Giardia infection (giardiasis): Giardiasis typically causes diarrhea, soft or greasy stools, nausea, fatigue, abdominal cramping and bloating, and weight loss.
Guinea worm disease: Symptoms of guinea worm disease develop after about one year, when adult guinea worm is ready to release its eggs. Symptoms develop a few days to hours before the adult worm emerges through the skin, to release its eggs. The patient may develop a fever and have pain and swelling in the area near the worm. A blister, which eventually forms an open wound, develops near the worm. When the wound is immersed in water, the tip of the worm begins to emerge from the skin to lay its eggs. Although these worms may be present in any area of the body, they are usually found on the legs or feet. After the worm emerges, it goes back inside the body, and the wound becomes painful and swollen.
Histoplasmosis: The most common form of histoplasmosis causes no symptoms. However, the parasite is present in the body for the rest of his/her life.
Patients who are symptomatic usually develop symptoms three to 17 days after exposure. Common symptoms include fever, headache, dry cough, chills, chest pain, weight loss, and sweats.
When a fungal infection enters the bloodstream and affects multiple body tissues and organs, the condition is often life threatening. Histoplasmosis may spread to virtually any part of the body, including the liver, bone marrow, eyes, skin, adrenal glands, and/or intestinal tract. When this happens, the condition is called disseminated histoplasmosis. Symptoms vary depending on which organs are infected.
Hookworm infection: Most patients with hookworm infections do not experience any symptoms. Some patients may develop an itchy skin rash where the worm entered the body. When the worm enters the lung, some patients may develop symptoms similar to asthma or pneumonia, such as persistent cough, wheezing, or difficulty breathing. When the worm enters the intestine, patients may experience abdominal pain, diarrhea, weight loss, decreased appetite, and excessive gas.
Leishmaniasis: Patients with leishmaniasis typically develop skin sores weeks to months after the parasite enters the body. The skin may become red, ulcerated, or have lesions, blisters, or pimples. Smaller lesions may be present around one larger ulcer.
Some patients may develop a stuffy or runny nose, nosebleeds, difficulty breathing, difficulty swallowing, as well as ulcers and sores in the mouth, tongue, gums, lips, nose, and the wall that separates the nostrils (called the nasal septum).
The parasite may also enter the bloodstream and burrow into internal organs. If internal organs are involved, symptoms may include persistent fever, night sweats, fatigue, weakness, appetite loss, weight loss, vomiting (most common in children), abdominal pain, scaly skin, gray or dark skin, and thinning hair.
Loiasis: Symptoms include irritated and watery itchy eyes, blurred vision, and eye discharge (called eye congestion). Patients may be able to see the thread-like worms move across their own eyeballs.
Lymphatic filariasis: Symptoms of lymphatic filariasis generally develop 5-18 months after being bitten by an infected mosquito. Lymphatic filariasis causes tissue damage that limits the normal flow of lymph fluid through the body. As a result, patients typically experience swelling, scarring, and infections, especially of the legs and groin.
Malaria: Symptoms of malaria include cycles of chills, fever, and sweating. These symptoms occur in cycles every one, two, or three days if the infection is not treated. Some individuals may also experience diarrhea, jaundice (yellowing of the skin and eyes), coughing, nausea, and vomiting.
Ringworm: Athlete's foot (tinea pedis) may cause burning or itching anywhere on the feet. Symptoms are usually most noticeable in between the toes. Patients may also develop itchy blisters, cracked or peeling skin, dry skin, or toenails that are thick, crumbly, discolored, or pulling away from the nail bed.
Jock itch (tinea cruris) typically causes the skin near the genitals, buttocks, and inner thighs to become red and itchy. The skin may also start to peel or crack.
Patients with ringworm of the scalp (tinea capitis) typically develop a circle-shaped rash on the skin that is swollen. The skin may be scaly and itchy. There may be small black dots on the scalp. Patients may lose small patches of hair. However, the hair will grow back once treatment is started.
Ringworm of the skin (tinea corporis) causes a circular red rash to form on the skin. This rash typically develops in patches and may be raised. The skin may be also be scaly and flakey.
River blindness (onchocerciasis): Symptoms usually develop one to three years after the larvae enter the body. Patients may develop an itchy skin rash, skin lesions, loss of skin pigmentation (which causes the skin to become white), enlarged lymph nodes, visual impairment, and sometimes blindness.
Scabies: Scabies causes pimple-like irritations, burrows, or a rash to develop on the skin. The skin on the wrists, elbows, knees, genitals (in men), breasts (in females), shoulder blades, and between the fingers is most likely to be affected. The affected skin is extremely itchy, especially at night. Individuals may also develop sores and small cuts from scratching the skin.
Tapeworm infection: Tapeworm infections do not always cause symptoms. The most common symptoms include weakness, nausea, decreased appetite, diarrhea, weight loss, and abdominal pain. Some patients may be able to see small white tapeworm eggs in their stools.
Threadworm infection: The signs and symptoms of threadworm infection vary, depending on the stage of the disease.
After the larvae enter the body through the skin, the area may be swollen and itchy, similar to a bug bite. Patients with long-term threadworm infections may develop an itchy skin rash near the buttocks, abdomen, and/or thighs.
Some patients may only have mild diarrhea and cramping, while others may have nausea, vomiting, fever, fatigue, and blood or mucus in the stools.
When the larvae move to the lungs and airways, the patient may develop a dry cough, fever, or difficulty breathing and may cough up blood or pus.
Trichinosis: Symptoms of trichinosis range from mild to severe, depending on the number of parasites in the body. Patients with a very mild form may experience no symptoms at all. When the parasite is in the intestine, common symptoms include diarrhea, abdominal pain, and general feeling of discomfort.
About one week after the parasite enters the body, the females produce larvae that penetrate body tissues, including muscles. Symptoms at this stage may include high fever, muscle pain and tenderness, weakness, swelling of the eyelids or face, sensitivity to light, headache, and pinkeye (called conjunctivitis).
Whipworm infection: Symptoms range from mild to severe. Common symptoms include abdominal pain and diarrhea. A severe infection may cause bloody diarrhea, iron-deficiency anemia and, sometimes, rectal prolapse, which occurs when the rectum slips down outside the anus.
Diagnosis
A parasitic infection is suspected if a patient has signs and symptoms of an infection and lives in or has visited an area known to have certain parasites. A diagnosis is confirmed after the parasite is identified in the body. Samples of blood, stool, urine, or phlegm may be analyzed for the presence of parasites.
A tissue biopsy may also be performed. During the procedure a small sample of tissue from the affected area, such as the lungs or intestines, may be taken. The sample is then analyzed for the presence of parasites.
Complications
Chiggers: If patients scratch chigger bites, the skin may break. This increases the risk of developing secondary infections.
Giardia infection (giardiasis): Giardiasis typically causes diarrhea, which causes the body to lose water and salts. As a result, patients may become dehydrated.
Patients with giardiasis may become lactose intolerant. Individuals may continue to be lactose intolerant for several weeks after the infection is treated.
Guinea worm disease: Guinea worm disease often causes severe pain that may be crippling.
Histoplasmosis: Disseminated histoplasmosis may lead to severe and fatal complications, including pneumonia, pericarditis, meningitis, and/or adrenal insufficiency.
Hookworm infection: Long-term hookworm infections may cause the patient to become anemic because the worms feed on the patient's blood. Symptoms of anemia may include difficulty breathing, pale complexion, fatigue, weakness, fast heartbeat, generalized swelling, or bloating. Once the parasite is killed, symptoms of anemia will resolve.
Leishmaniasis: Patients with leishmaniasis may develop allergic reactions when the larvae enter the muscle tissue. This typically happens when the dead or dying larvae release chemicals into the tissues. The body's immune system overreacts to these chemicals, and allergic symptoms, such as hives and itchy eyes, develop.
Loaisis: If left untreated, the Loa loa worm may sometimes enter the brain, causing brain swelling (called encephalitis) and possibly brain damage.
River blindness (onchocerciasis): If left untreated, river blindness may cause permanent blindness.
Scabies: Individuals with scabies often develop sores and small cuts from scratching affected areas of skin. If bacteria enter the skin through these sores or cuts, an infection may develop.
Tapeworm infection: Tapeworm infections may lead to malnutrition. The parasites absorb many of the nutrients from the food its host eats before the patient is able to do so. As a result, the patient may not get the necessary vitamins and minerals to stay healthy. This may also lead to weight loss. Once the parasite is killed, the patient will be able to absorb nutrients and will gain back lost weight.
Threadworm infection: If the larvae spread to other organs in the body, the condition is called hyperinfection syndrome. Symptoms of this condition may include inflammation of the heart tissue, stomach ulcers, perforations of the intestines, blood poisoning, meningitis (which often causes fever, headache, vomiting, nausea, confusion, and fatigue), sudden and life-threatening drop in blood flow throughout the body (called shock), and possible death.
Treatment
Anti-helminthic (anti-parasitic): Anti-helminthic drugs are used to kill parasites that have entered the body. They may be taken by mouth, applied to the skin, or injected into the vein. Treatment varies, depending on the type and severity of the infection.
The most commonly prescribed medication to treat ascariasis includes mebendazole (Vermox?), albendazole (Albenza?), and pyrantel (Antiminth? or Pin-Rid?).
Hookworm is generally treated with the drug mebendazole (Vermox?). According to researchers, mebendazole cures more than 99% of hookworm infections if it is taken twice a day for three days. It kills both the worms and the eggs. Albendazole (Albenza?) or pyrantel (Antiminth?) may be taken as alternatives. These drugs are taken once per day for three days.
Loiasis is typically treated with diethylcarbamazine (Hetrazan?) or ivermectin (Stromectol?).
Patients with threadworm infections typically take ivermectin (Stromectol?), thiabendazole (Mintezol?), or albendazole (Albenza?) by mouth for two to seven days. Ivermectin is considered the standard treatment because it has fewer side effects than the other drugs. These drugs work by preventing new eggs and larvae from developing.
Lymphatic filariasis may be treated with either albendazole (Albenza?) or diethylcarbamazine (Hetrazan?).
Patients with river blindness (onchocerciasis) typically take ivermectin (Stromectol?). Treatment may need to be repeated once or twice a year because the drug only kills the immature worms, not the adult worms, which can live for many years.
Trichinosis is generally treated with albendazole (Albenza?) or mebandazole (Vermox?) to kill the adult worms and larvae. Depending on how severe the infection is, some patients may need to take repeat doses to completely eliminate the worms.
Patients with whipworm infections typically taken mebendazole (Vermox?) by mouth for about three days. Albendazole (Albenza? is used as an alternative therapy for whipworm infections.
Antimalarials: Malaria is treated with a combination of antimalarials, which may include chloroquine (Aralen?), quinine, hydroxychloroquine (Plaquenil?), mefloquine (Lariam?), doxycycline (Doryx? or Vibramycin?), sulfadoxine/pyrimethamine (Fansidar?), or atovaquone/proguanil (Malarone?). Treatment usually lasts about three days.
Antimony-containing compounds: Drugs that contain antimony, which is an anti-parasitic, are often used to treat leishmaniasis. Examples of antimony-containing medications include meglumine antimonite and sodium stibogluconate.
Scabicide: Drugs called scabicides are used to treat scabies. Many skin lotions or creams, such as Lindane, permethrin (Acticin? or Elimite?), or crotamiton (Eurax Cream? or Eurax Lotion?), are applied to the skin from the neck down to kill the parasitic eggs. Treatment lasts for seven days to ensure that all the eggs are killed. Itching often lasts for about one week after treatment ends. Family members, sexual contacts, and others who have had skin-to-skin contact with a person diagnosed with scabies should also be treated.
Antifungals: Patients who have severe cases of histoplasmosis, including disseminated histoplasmosis, usually receive treatment with an intravenous antifungal medication called amphotericin B (Amphocin? or Fungizone?). Since the drug may be toxic to the kidney, it is generally injected into the patient's vein. After a few days to weeks of treatment, doctors usually switch to a drug called itraconazole (Diflucan?, Nizoral?, or Sporanox?). HIV/AIDS patients will need to take itraconazole for life in order to prevent the infection from recurring.
Mild cases of disseminated histoplasmosis may be treated with itraconazole alone. Although this drug generally does not work as quickly as amphotericin B, it causes fewer side effects and can be taken by mouth. Side effects of itraconazole may include headache, dizziness, nausea, vomiting or diarrhea, but these symptoms often go away over time. Use cautiously with a history of liver or kidney problems, or another lung disease. Patients should be monitored closely during treatment.
Pentamidine and Amphotericin B have been used to treat leishmaniasis.
Corticosteroids: Patients with leishmaniasis who develop allergic reactions to the larvae are often prescribed medications called corticosteroids. These medications, including prednisone (such as Deltasone?), help reduce inflammation and allergic symptoms, such as hives or itchy eyes.
Iron supplements: Iron supplements have been used to treat patients with hookworm infections. Iron supplements may help improve a patient's recovery if they are anemic. Patients should talk to their healthcare providers to determine whether or not iron supplementation is necessary.
Pain relievers: Many parasitic infections, including trichinosis and guinea worm disease, may cause severe pain. Commonly used pain relievers include ibuprofen (Motrin? or Advil?) and acetaminophen (Aspirin-Free Anacin?, Tylenol?, or Feverall?).
Hydrocortisone: Hydrocortisone cream has been used to treat chigger bites. The cream is applied to the area to temporarily relieve itching. Hydrocortisone 1% cream, which is available over-the-counter, has anti-inflammatory effects and relieves swelling and redness in addition to itching. Antipruritic (relieves itching) agents, such as calamine lotion (Calamox?) have been applied to the skin to relieve itching
Surgery: Surgery may be necessary to repair intestinal damage or remove worms in patients who have severe ascariasis. The only treatment for guinea worm disease is to surgically remove the worm. Once the worm is removed, the remaining eggs will be excreted in the feces, and the infection is cured.
Other: Since guinea worm disease often occurs in areas of the world where surgery is not widely available, individuals have traditionally used another method to remove the worm. The patient soaks the affected area in water until the worm emerges from the blister. Then a small stick is wrapped around the end of the worm. The worm is pulled out a tiny bit at a time. Sometimes the worm can be pulled out completely within a few days. However, it usually takes several weeks to months for the worm to be completely removed. There are serious health risks associated with this method. If the patient tries to pull too much of the worm out, the worm may break in half. This kills the worm, and releases toxins into the bloodstream. The patient may then suffer from a severe infection. Therefore, this method should only be used as a last resort.
Integrative therapies
Good scientific evidence:
Vitamin A: Vitamin A is a fat-soluble vitamin that is derived from two sources: preformed retinoids and provitamin carotenoids. Retinoids, such as retinal and retinoic acid, are found in animal sources like liver, kidney, eggs, and dairy produce. Carotenoids like beta-carotene (which has the highest vitamin A activity) are found in plants such as dark or yellow vegetables and carrots. Limited research suggests that vitamin A may reduce fever, morbidity, and parasite blood levels in patients with malaria (
Plasmodium falciparum infection). However, evidence is currently lacking that vitamin A is equivalent or superior to well-established drug therapies used for the prevention or treatment of malaria. Individuals with malaria or living/traveling in endemic areas should speak with a doctor about appropriate measures.
Vitamin A toxicity, or hypervitaminosis A, is rare in the general population. Vitamin A toxicity can occur with excessive amounts of vitamin A taken over short or long periods of time. Avoid if allergic or hypersensitive to vitamin A. Use cautiously with liver disease or alcoholism. Smokers who consume alcohol and beta-carotene may be at an increased risk for lung cancer or heart disease. Vitamin A appears safe in pregnant women if taken at recommended doses; however, vitamin A excess, as well as deficiency, has been associated with birth defects. Excessive doses of vitamin A have been associated with central nervous system malformations. Use cautiously if breastfeeding because the benefits or dangers to nursing infants are not clearly established.
Zinc: Zinc formulations have been used since ancient Egyptian times to enhance wound healing. Evidence from human trials suggests that zinc pyrithione shampoo may be an effective treatment for tinea versicolor fungal infections of the scalp. Side effects were not noted. Additional research is needed before a strong recommendation can be made.
Zinc is generally considered safe when taken at the recommended dosages. Avoid zinc chloride since studies have not been done on its safety or effectiveness. While zinc appears safe during pregnancy in amounts lower than the established upper intake level, caution should be used since studies cannot rule out the possibility of harm to the fetus.
Unclear or conflicting scientific evidence:
Berberine: Berberine is a bitter-tasting, yellow, plant alkaloid with a long history of medicinal use in Chinese and Ayurvedic medicine. Berberine has been found to possess antimicrobial properties, and there is limited evidence of anti-inflammatory properties as well. The benefits of berberine in the treatment of leishmaniasis are widely accepted. Berberine is thought to be equally efficacious as the standard drug treatment for cutaneous leishmaniasis, antimonite (sulfide mineral), although limited study of this treatment probably limits its widespread use. Human study has also assessed the use of berberine in combination with pyrimethamine in the treatment of chloroquine-resistant malaria. Well-designed clinical trials are still required.
Avoid if allergic or hypersensitive to berberine, to plants that contain berberine (Hydrastis canadensis (goldenseal), Coptis chinensis (coptis or goldenthread), Berberis aquifolium (Oregon grape), Berberis vulgaris (barberry), and Berberis aristata (tree turmeric), or to members of the Berberidaceae family. Avoid in newborns due to the potential for an increase in free bilirubin, jaundice, and development of kernicterus. Use cautiously with cardiovascular disease, gastrointestinal disorders, hematologic disorders, leukopenia, kidney disease, liver disease, respiratory disorders, cancer, hypertyraminemia, diabetes, or low blood pressure. Use cautiously in children due to a lack of safety information. Use cautiously in individuals with high exposure to sunlight or artificial light. Use cautiously for longer than eight weeks due to theoretical changes in bacterial gut flora. Use cautiously if taking anticoagulants, antihypertensives, sedatives, anti-inflammatories, medications metabolized by CYP P450 3A4 including cyclosporin, or any prescription medications. Avoid if pregnant or breastfeeding.
Bishop's weed: Limited available human study used 8-methoxypsoralen (8-MOP), a photoreactive plant compound from bishopsweed, for the treatment of tinea versicolor. Clinical studies are needed before a conclusion can be made.
Use cautiously in patients with photosensitivity as bishop's weed may be photoreactive, and cause phototoxic skin damage, phototoxic dermatitis, and pigmentary retinopathy. Use cautiously in patients with bleeding disorders or taking anticoagulants, NSAIDs/anti-platelet agents, or herbs or supplements that increase risk of bleeding because bishop's weed may have additive effects and increase the risk of bleeding. Use cautiously in patients taking drugs or herbs or supplements metabolized by cytochrome P450 as bishop's weed may increase the effects of these agents. Use cautiously in patients with eye disorders, as bishop's weed may cause ocular toxicity. Avoid in patients with known allergy/hypersensitivity to bishop's weed, its constituents, or members of the Apiaceae family.
Bitter orange: Limited available human study found promising results using the oil of bitter orange for treatment of fungal infections. However, due to methodological weakness of this research, further evidence is needed to confirm these results.
Avoid if allergic or hypersensitive to bitter orange or any members of the Rutaceae family. Avoid with heart disease, narrow-angel glaucoma, intestinal colic, or long QT interval syndrome. Avoid if taking anti-adrenergic agents, beta-blockers, QT-interval prolonging drugs, monoamine oxidase inhibitors (MAOIs), stimulants, or honey. Use cautiously with headache, hyperthyroidism (overactive thyroid), or if fair-skinned. Avoid if pregnant or breastfeeding.
Cinnamon: There is currently a lack of available evidence to support the use of cinnamon for AIDS patients with advanced oral candidiasis. More study is needed in this area.
Avoid if allergic or hypersensitive to cinnamon, its constituents, members of the Lauraceae family, or Balsam of Peru. Use cautiously if prone to atopic reactions or if taking cytochrome P450 metabolized agents, anticoagulants (blood thinners), insulin or blood sugar-altering medications, antibiotics, or cardiovascular agents. Avoid if pregnant or breastfeeding.
Corydalis: Corydalis may be helpful in the treatment of infections caused by the parasite
Echinococcus granulosus caused by the Hydatid worm. More studies are needed to confirm the antiparasitic effects of corydalis.
Corydalis is generally considered to be safe. Avoid if allergic or sensitive to corydalis. Avoid if taking sedative or hypnotic drugs, drugs that treat abnormal heart rhythms (including bepridil), pain relievers, and anti-cancer drugs. Avoid if pregnant or breastfeeding.
Cranberry: Limited laboratory research has examined the antifungal activity of cranberry. Further research is warranted in this area.
Avoid if allergic to cranberries, blueberries, or other plants of the Vaccinium species. Sweetened cranberry juice may affect blood sugar levels. Use cautiously with a history of kidney stones. Pregnant and breastfeeding women should avoid cranberry in higher amounts than what is typically found in foods.
Garlic: Garlic is used both medicinally and as a food spice. Preliminary research suggests that oral plus intravenous garlic may help manage symptoms of cryptococcal meningitis, a fungal infection that commonly occurs in HIV patients. Further research is needed before recommending for or against the use of garlic in the treatment of this potentially serious condition, for which other treatments are available. Several studies describe the use of garlic as a topical antifungal to treat fungal infections of the skin, including yeast infections. More research is needed in this area.
Use cautiously as garlic can cause severe burns and rash when applied to the skin of sensitive individuals.
Avoid if allergic or hypersensitive to garlic or other members of the Lilaceae(lily) family (e.g. hyacinth, tulip, onion, leek, or chive). Avoid with a history of bleeding problems, asthma, diabetes, low blood pressure, or thyroid disorders. Stop using supplemental garlic two weeks before and immediately after dental/surgical/diagnostic procedures with bleeding risks. Avoid in supplemental doses if pregnant or breastfeeding.
Goldenseal: Goldenseal is one of the five top-selling herbal products in the United States. However, there is little scientific evidence about its safety or effectiveness. A small amount of research reports that berberine, a chemical found in goldenseal, may be beneficial in the treatment of chloroquine-resistant malaria when used in combination with pyrimethamine. Due to the very small amount of berberine found in most goldenseal preparations, it is unclear whether goldenseal contains enough berberine to have these effects. More research is needed before a recommendation can be made.
Avoid if allergic or hypersensitive to goldenseal or any of its constituents, like berberine and hydrastine. Use cautiously with bleeding disorders, diabetes, or low blood sugar. Avoid if pregnant or breastfeeding.
Iodine: Povidone-iodine has been suggested as a topical treatment for molluscum contagiosum. Research is limited in this area.
There have been reports of severe and even fatal reactions to iodine. Avoid iodine-based products if allergic to iodine. Do not use for more than 14 days. Avoid lugol solution and the saturated solution of potassium iodide (SSKI, PIMA) with high amounts of potassium in the blood, fluid in the lungs, bronchitis, or tuberculosis. Use cautiously when applying to the skin because it may irritate or burn tissues. Use sodium iodide cautiously with kidney failure. Avoid sodium iodide with gastrointestinal obstruction. Iodine is considered to be safe in recommended doses for pregnant or breastfeeding women. Avoid povidone-iodine for perianal preparation during delivery or postpartum antisepsis.
Oregano: Early study shows that taking oregano by mouth may help treat parasites. Further research is needed to confirm these results.
Research suggests that oregano is well tolerated in recommended doses. Avoid if allergic or hypersensitive to oregano. Use caution if allergic or hypersensitive to other herbs from the Lamiaceae family including hyssop, basil, marjoram, mint, sage and lavender. Use caution with diabetes and bleeding disorders.Pregnant or breastfeeding women should not consume oregano at doses above those normally found in food.
Pomegranate: In clinical study, an extract of pomegranate was shown to be as effective as a commonly used oral gel when used topically to treat candidiasis associated with denture stomatitis (mouth sores). Additional study is needed to confirm pomegranate's antifungal effects.
Avoid if allergic or hypersensitive to pomegranate. Avoid with diarrhea or high or low blood pressure. Avoid taking pomegranate fruit husk with oil or fats to treat parasites. Pomegranate root/stem bark should only be used under the supervision of a qualified healthcare professional. Use cautiously with liver damage or liver disease. Pomegranate supplementation may be unsafe during pregnancy when taken by mouth. The bark, root, and fruit rind may cause menstruation or uterine contractions. Avoid if breastfeeding due to a lack of scientific data.
Probiotics: Combining a probiotic yeast (
Saccharomyces boulardii) with antibiotics in the treatment of acute amoebiasis (amoebic dysentery) may decrease the duration of symptoms. Early research suggests that cheese containing probiotics may help reduce the risk of a fungal mouth infection, called thrush, in the elderly. More studies are needed to determine the effectiveness of probiotics for these indications.
Probiotics are generally considered to be safe and well-tolerated. Avoid if allergic or hypersensitive to probiotics. Use cautiously if lactose intolerant. Caution is advised when using probiotics in neonates born prematurely or with immune deficiency.
Propolis: Propolis is a natural resin created by bees to make their hives. Propolis is made from the buds of conifer and poplar trees and combined with beeswax and other bee secretions. Animal and laboratory studies suggest that propolis may be a beneficial treatment for various types of fungal infections. In humans, a commercial propolis ethanol extract from Brazil, formulated to ensure physical and chemical stability, was found to inhibit fungal infections of the mouth, such as oral candidiasis. Additional research is needed to confirm these findings.
Avoid if allergic or hypersensitive to propolis, black poplar (Populas nigra), poplar bud, bee stings, bee products, honey, or Balsam of Peru. Severe allergic reactions have been reported. There has been one report of kidney failure with the ingestion of propolis that improved upon discontinuing therapy and deteriorated with re-exposure. Avoid if pregnant or breastfeeding because of the high alcohol content in some products.
Riboflavin (vitamin B12): Riboflavin is a water-soluble vitamin. It is needed for normal cell function, growth, and energy production. Small amounts of riboflavin are found in most animal and plant tissues. Low riboflavin levels have been associated with anti-malarial effects. However, it remains unclear exactly how riboflavin supplementation may affect malaria. Additional research is needed in this area.
Avoid if allergic or hypersensitive to riboflavin. Since the amount of riboflavin a human can absorb is limited, riboflavin is generally considered safe. Riboflavin is generally regarded as safe during pregnancy and breastfeeding.
Seaweed, kelp, bladderwrack: Bladderwrack (
Fucus vesiculosus) is a brown seaweed found along the northern coasts of the Atlantic and Pacific oceans and North and Baltic seas. Another seaweed that grows alongside bladderwrack is
Ascophyllum nodosum, and
it is often combined with bladderwrack in kelp preparations. Laboratory research suggests that bladderwrack may have antifungal activity. However, reliable human studies to support this use are currently lacking in the available literature.
Avoid if allergic or hypersensitive to Fucus vesiculosus or iodine. Avoid with a history of thyroid disease, bleeding, acne, kidney disease, blood clots, nerve disorders, high blood pressure, stroke, or diabetes. Avoid if pregnant or breastfeeding.
Selenium: Selenium is a mineral found in soil, water, and some foods. Preliminary research reports that selenium may be beneficial in the prevention of several types of infection. Commercially available 1% selenium sulfide shampoo has been reported as equivalent to sporicidal therapy in the adjunctive treatment of tinea capitis yeast infections. Selenium sulfide shampoo has also been studied as a possible treatment for tinea versicolor. However, research results are inconclusive.
Avoid if allergic or hypersensitive to products containing selenium. Avoid with a history of non-melanoma skin cancer. Selenium is generally regarded as safe for pregnant or breastfeeding women. However, animal research reports that large doses of selenium may lead to birth defects.
Sweet annie: Sweet annie (
Artemisia annua) is also known as Chinese wormwood or sweet wormwood. Although there has been some interest in using sweet annie as an antimalarial therapy, there is currently not enough human evidence to support its use for malaria.
Avoid if allergic or hypersensitive to sweet annie (Artemisia annua), its constituents, or members of the Asteraceae/Compositae family such dandelion, goldenrod, ragweed, sunflower, and daisies. Use cautiously in patients who are pregnant, taking angiogenic agents, or recovering from surgery or other wounds. Use cautiously if taking cardiotoxic or neurotoxic agents or with compromised cardiac or neural function. Use cautiously if taking immunostimulants or quinolines. Avoid if pregnant or breastfeeding.
Tea tree oil: Tea tree oil is purported to have antiseptic properties, and has been used traditionally to prevent and treat infections. Although tea tree oil has been found to have activity against several fungus species in laboratory study, there is currently insufficient human evidence to determine if it is an effective topical treatment for onychomycosis, tinea pedis (athlete's foot), or thrush (oral
Candida albicans).
Tea tree oil may be toxic when taken by mouth and therefore, should not be swallowed. Avoid if allergic to tea tree oil or plants of the Myrtle (Myrtaceae) family, Balsam of Peru, or benzoin. Use cautiously with a history of eczema. Avoid if pregnant or breastfeeding.
Thyme: Thyme has been used medicinally for thousands of years. Beyond its common culinary application, it has been recommended for many indications based on proposed antimicrobial, antitussive, spasmolytic, and antioxidant activity. Thyme essential oil and thymol have been shown to have antifungal effects. Topical thymol has been used traditionally to treat paronychia (skin infection around a finger or toenail) and onycholysis (fungal nail infection)
. Currently, there is insufficient reliable human evidence to recommend for or against the use of thyme or thymol as a treatment for fungal infections.
Avoid if allergic or hypersensitive to thyme, members of the Lamiaceae (mint) family, any component of thyme, or rosemary (Rosmarinus officinalis). Avoid oral ingestion or non-diluted topical application of thyme oil due to potential toxicity. Avoid topical preparations in areas of skin breakdown or injury or in atopic patients due to multiple reports of contact dermatitis. Use cautiously with gastrointestinal irritation or peptic ulcer disease due to anecdotal reports of gastrointestinal irritation. Use cautiously with thyroid disorders due to observed anti-thyrotropic effects in animal research of the related species Thymus serpyllum. Avoid if pregnant or breastfeeding.
Vitamin A: After deworming, children supplemented with vitamin A may be less prone to infection with
Acaris parasites. These benefits may be less in children with stunted growth. More research is needed to make a conclusion.
Avoid if allergic to vitamin A. Vitamin A toxicity can occur if taken at high dosages. Use cautiously with liver disease or alcoholism. Smokers who consume alcohol and beta-carotene may have an increased risk of developing lung cancer or heart disease. Vitamin A appears safe in pregnant women if taken in recommended doses. Use cautiously if breastfeeding because the benefits or dangers to nursing infants are not clearly established.
Zinc: In a few studies, patients with cutaneous leishmaniasis were injected with zinc sulfate under the skin. Zinc may decrease the severity of infection and re-infection of
S.
mansoni, but does not seem to prevent initial infection. More research is necessary. The effects of zinc on the rate of parasitic re-infestation has been examined in children. No significant effect of zinc treatment was found. Recent data suggest that supplementation with zinc and vitamin A may favorably alter infection rate and duration among children. Due to conflicting results in this area, more research is needed before zinc can be recommended for the treatment of parasites.
Results are contradictory regarding the effect of zinc on malaria symptoms. Some randomized, double-blind clinical trials suggest no effect of zinc supplementation on the severity of malaria. Other studies suggest that zinc supplementation may reduce the number of stays in the hospital and death rate due to P. falciparum infection. Further well-designed, randomized and controlled trials are required to address these discrepancies.
Zinc (zinc sulfate, zinc acetate, zinc glycine, zinc oxide, zinc chelate, and zinc gluconate) is generally considered safe when taken in the recommended dosages. Avoid zinc chloride since studies have not been done on its safety or effectiveness. While zinc appears safe during pregnancy in amounts lower than the established upper intake level, caution should be used since studies cannot rule out the possibility of harm to the fetus.
Prevention
Wear gloves when gardening or handling soil. Wash hands thoroughly with soap and water after coming into contact with soil.
Wash hands with soap and water after changing a diaper.
Wash hands thoroughly before handling food.
Do not eat raw or undercooked meat. Individuals should be especially careful when preparing pork, venison, or lamb because they contain the most dangerous parasites.
Freezing meat or fish for at least 12 hours has been shown to kill tapeworm eggs.
Wash kitchen utensils thoroughly with soap and water.
Thoroughly wash all fruits and vegetables.
Avoid raw produce when visiting parts of the world with poor sanitation.
Individuals who are in areas of the world with poor sanitation should only drink bottled water. If this is not possible, individuals should boil their water before drinking it. This kills any parasites that may be living in the water.
Individuals who work in areas that are known to be infested with a parasitic fungus called Histoplasma capsulatum (e.g. caves or birds coops) should wear a face mask. This prevents the spores from entering the individual's mouth or nose.
Since many insects, including mosquitoes, deerflies, and sandflies, are known to carry parasitic diseases, individuals should consider wearing insect repellent when outdoors. Also, since mosquitoes are most active at dawn and dusk, individuals should limit the time spent outdoors during these peak times. In addition, individuals should get rid of items around the home that collect water (such as buckets and empty flower pots) because mosquitoes lay their eggs on the surface of water.
Patients who are visiting tropical areas of the world where malaria is common should sleep with a bednet to prevent mosquitoes and other bugs from transmitting diseases during the night.
Individuals who plan to travel to areas where parasitic infections are common (such as Africa, Asia, the Middle East, South America, and Central America), should talk to their healthcare providers to learn how to reduce their risks of acquiring infections.
Author information
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Bibliography
Centers for Disease Control and Prevention (CDC). .
Dupouy-Camet J. New challenges in trichinellosis control. Wiad Parazytol. 2006;52(3):155-6.
Fox LM, Furness BW, Haser JK, et al. Tolerance and efficacy of combined diethylcarbamazine and albendazole for treatment of Wuchereria bancrofti and intestinal helminth infections in Haitian children. Am J Trop Med Hyg. 2005 Jul;73(1):115-21.
Genetics Home Reference. .
Greenaway C. Dracunculiasis (guinea worm disease). CMAJ. 2004 Feb 17;170(4):495-500.
National Institute of Allergy and Infectious Diseases. .
Natural Standard: The Authority on Integrative Medicine. .
Olsen A. Efficacy and safety of drug combinations in the treatment of schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis and onchocerciasis. Trans R Soc Trop Med Hyg. 2007 May 2; [Epub ahead of print.]
Rana SS, Bhasin DK, Nanda M, et al. Parasitic infestations of the biliary tract. Curr Gastroenterol Rep. 2007 Apr;9(2):156-64.
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Common types and causes of parasitic infections
Ascariasis: Ascariasis is a type of parasitic infection that is caused by a roundworm called Ascaris lumbricoides. Humans become infected after they ingest the parasite's microscopic eggs. The parasite can be transmitted when humans eat produce that is grown in soil that has been mixed with infected human feces. This is most common in developing countries where human feces are used as fertilizer for crops or where there is poor sanitation.
Once the eggs enter the body, they mature into larvae. The larvae then enter the lungs. Eventually, the larvae reach the throat, where they are coughed up and then swallowed. Once swallowed, the larvae enter the intestines, where they develop into adults and feed off of the food that enters the body. Adult worms can grow to be 15 inches long. Adult worms can live up to two years, and female worms can produce more than 200,000 eggs a day. These eggs are released in the patient's feces.
Ascariasis is considered the most common type of roundworm infection in humans. Researchers estimate that about 25% of the world's population is infected with the parasite. In the United States, most infections occur in rural areas that have warm climates, such as the Southern United States.
Chiggers: Chiggers are the parasitic larvae of the harvest mite. While the adults are harmless to humans, the larvae are parasites to many animals, including birds, livestock, reptiles, and humans. Chigger bites only occur during the late summer and early autumn because this is when the larvae are active.
Chiggers are found in many parts of the world, including the Southern United States. Chiggers typically live in brush and grassy areas. Females lay up to 400 eggs in damp areas on the ground.
Once the eggs have developed into larvae (called chiggers), they move to the tips of grasses. When a potential host, such as a rodent or human passes by, the chigger latches on. The chiggers then move to protected areas on the host, such as under socks or under belts.
Chiggers pierce the skin, especially near hair follicles. When they pierce the skin, they secrete digestive enzymes from their saliva and then they suck up and ingest the liquefied host tissues. The rash and intense itching that develops after a chigger bite is an allergic reaction to their salivary secretions. Once the larva is fully fed, it drops off the host.
Giardia infection (giardiasis): Giardiasis occurs when an intestinal parasite called Giardia lamblia infects a human. Giardiasis typically causes abdominal pain, nausea, and diarrhea.
Humans contract giardiasis after consuming food or water that is contaminated with Giardia lamblia. Once consumed, the parasitic eggs (called cysts) hatch in the stomach. The parasite then attaches to the small intestine where it feeds on the food that is consumed by its host.
Giardiasis is common throughout the world, including the United States.
Guinea worm disease: Guinea disease is a painful parasitic infection caused by a roundworm, called the guinea worm (Dracunculus medinensis). Patients become infected with this worm when they drink water that is contaminated with a tiny water flea that is infected with tiny guinea worm larvae. The guinea worm larvae are only found in Africa.
Once the larvae enter the human, they mature into adults in the human gut. Inside the host, these adult worms can grow up to be three feet long. The adult then migrates to an area of the body (almost always the legs) from which it will eventually emerge.
After about one year, the adult worm is ready to release its eggs. When this happens, a small part of the worm will emerge through a painful, round blister in the skin. The tip of the adult worm breaks through the skin to release its eggs into water. The adult worm will continue to emerge and lay eggs whenever the affected limb is submerged in water. This often causes long-term suffering and sometimes crippling effects in the human host.
Histoplasmosis: Histoplasmosis is a parasitic infection of the lungs that may spread to other organs and tissues of the body. Histoplasmosis is caused by a parasitic fungus called Histoplasma capsulatum. This parasitic fungus is most prevalent in Ohio, Missouri, and the Mississippi river valleys.
Humans typically become infected with the parasitic fungus when they inhale the spores of the fungus. The tiny spores become airborne when dirt or other contaminated substances (especially droppings from birds or bats) is disturbed.
Most patients with histoplasmosis do not experience any symptoms of the disease and do not require treatment. This is because healthy individuals have strong immune systems that are able to prevent the parasitic fungi from multiplying and causing an infection. However, patients with weakened immune systems, especially HIV patients and infants, are vulnerable to developing infections that start in the lungs and spread to other areas of the body. When the infection spreads, it is called disseminated histoplasmosis. This condition is fatal if left untreated.
Patients with underlying diseases, such as emphysema, are also vulnerable to developing a long-term infection that primarily affects the lungs. When this happens, the condition is called chronic pulmonary histoplasmosis. Patients with this type of infection require lifelong treatment with antifungals.
In some cases, otherwise healthy individuals may develop histoplasmosis infections. This may happen if the patient is exposed to large amounts of the parasitic fungus. For instance, farmers who are frequently exposed to soil or bird or bat droppings have an increased risk of developing infections.
Hookworm infection: A hookworm infection is caused by one of two different types of roundworms: Ancylostoma duodenale or Necator americanus. If not treated, Hookworm infections can lead to abdominal pain and iron deficiency. Researchers estimate that about 20% of the world's population is infected with hookworm.
Humans become infected with hookworm when they come into contact with contaminated soil or stool. The larvae enter through the skin and travel through the blood to the lungs. Eventually, the larvae reach the throat, where they are coughed up and swallowed. As the larvae enter the digestive tract, they attach themselves to the wall of the small intestine. Here they mature into adult worms and mate. The worms feed on the blood of the host, which may lead to iron deficiency. Adult hookworms may live up to ten years.
Leishmaniasis: Leishmaniasis is a parasitic disease that is caused by protozoa called leishmania. Humans become infected with the parasite after they are bitten by a sandfly that is infected with the leishmania larvae. Sandflies are blood-sucking insects that are commonly found on beaches and marshes. They are especially common in Florida.
There are many different types of leishmaniasis. The most common form is a skin disease called cutaneous leishmaniasis. This infection causes skin sores, which may or may not be painful. The sores have raised edges and a flat center.
Loiasis: Loiasis is a parasitic infection that is caused by a roundworm called the African eye worm (Loa loa). Humans become infected with the parasite after they are bitten by the deer fly chrysops (typically found near the Congo River region, Sudan, and Ethiopia) that is carrying the immature African eye worm. Once the parasite enters the human host, it migrates toward the eyes, where it causes eye congestion and irritation. Sometimes the worms move to the brain, where it causes brain swelling, which is potentially fatal.
Loiasis is most prevalent in tropical areas of Africa.
Lymphatic filariasis: A filarial infection (called filariasis) is a type of infection that is caused by any of the round, thread-like parasitic worms. Lymphatic filariasis, also called elephantiasis, is caused by a worm (either Wuchereria bancrofti or Brugia malayi) that infects the human lymph system. It is the most common type of filarial infection.
The infection is transmitted to humans when a mosquito infected with the larvae bites a person. Once the parasite enters the human, it migrates to the lymph nodes where it develops into an adult. Females release larvae, which circulate in the patient's bloodstream. Adult filarial worms typically live for about seven years, if not treated with anti-parasitic medications.
Although lymphatic filariasis is rarely fatal, it can cause fevers, frequent infections, and serious inflammation of the lymph system if it is not treated.
Malaria: Malaria is an infectious disease of the red blood cells that is caused by protozoan parasites called Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale. The protozoa live the first part of their lives inside mosquitoes. When an infected mosquito bites a human, malaria can be transmitted.
This life-threatening disease is most common in tropical and subtropical areas, such as Africa, Asia, the Middle East, South America, and Central America. According to the U.S. Centers for Disease Control and Prevention (CDC), about 350-500 million patients become infected with malaria each year. More than one million of these patients die, most of them young children from sub Saharan Africa.
Malaria can be successfully treated with anti-malarial medications. However, drug resistance is a growing problem in many countries.
Studies on malaria causing parasites have revealed two new distinct forms different from the form already being studied in labs. Understanding the genome of the parasite and all the variations may help researchers discover new methods to combat the disease.
Several genes have been shown to help protect against malaria. Studies on the major histocompatibility complex, class I, B gene, also known on HLA-B, has revealed a link to malaria. HLA-B gene is part of a family of genes known as human leukocyte antigen complex, which helps the body distinguish its own cells from foreign invaders like bacteria and viruses. A mutation on the HLA-B gene known as HLA-B53 has been shown to protect against malaria. Researchers believe that this mutation may help the immune system to respond better to the parasite that causes malaria.
A mutation in the glucose-6-phosphate dehydrogenase (G6PD) gene may also offer protection against malaria. The G6PD gene mutation causes glucose-6-phosphate dehydrogenase deficiency, which is a blood disorder that causes red blood cells to break down prematurely. This blood disorder appears to make it difficult for the parasite to penetrate the blood cells. G6PD deficiency is most common in the world where malaria is also most common.
Another genetic mutation that protects against malaria is the gene mutation that causes sickle cell anemia, a blood disorder that causes red blood cells to be sickle shaped. As a result, the abnormally shaped blood cells may block narrow blood vessels potentially leading to tissue damage. Sickle cell anemia is caused by a mutation on the ? globin gene which leads to abnormal hemoglobin. There are two alleles, or variations, of the ? globin gene: A and S. Individuals with two normal alleles (AA) have normal hemoglobin and normal RBCs. Individuals who have two mutated alleles (SS) produce abnormal hemoglobin and have sickle cell anemia, but individuals who only carry the allele (AS) produce both abnormal and normal hemoglobin. These individuals are usually healthy and do not develop sickle cell anemia, have been found to be more resistant to malaria than others, and are able to survive in regions with high rates of malaria.
Ringworm: There are many different types of ringworm infections, all of which infect different parts of the body, including the feet, genitals, scalp, and top layer of the skin. Ringworm is named after the round shape that often forms when an infection develops. It does not involve an actual worm in the body.
Athlete's foot (tinea pedis) is a ringworm infection of the foot that causes itching, stinging, and burning. A group of parasitic fungi, called dermatophytes, cause athlete's foot. These fungi prefer warm moist environments. Individuals whose feet are exposed to this type of environment have an increased risk of developing an infection. Patients may be exposed to the fungi when they shower barefoot in a public facility, such as a gym. Once the fungus comes into contact with human skin, it begins to reproduce. As a result, the top layer of the skin produces more skin cells than normal. This causes the skin on the feet to become thick, scaly, and itchy. Most cases of athlete's foot can be treated with over-the-counter (OTC) antifungal medications. More severe infections that do not respond to OTC treatment may require prescription-strength antifungals.
Jock itch, also called tinea cruris, is a ringworm infection that affects the skin of the inner thighs, buttocks, and genitals. Jock itch is caused by a group of fungi called dermatophytes. The fungi that cause jock itch are usually the same organisms that cause athlete's foot and tinea capitis (ringworm of the scalp). These organisms normally live on the skin and do not cause an infection. However, when areas of the body are frequently moist, the fungi may grow uncontrollably. Although anyone can acquire the infection, it is most common in individuals who sweat a lot, such as athletes or those who are overweight. This is because a warm and sweaty environment provides an especially good habitat for fungi. Jock itch is mildly contagious. It may spread through physical contact or after using shared items (e.g. towels) that came into contact with the infected person's skin. Jock itch is not a serious infection. It is usually treated with antifungals that are applied to the skin.
Tinea capitis, also called ringworm of the scalp, is a skin infection of the head. Tinea capitis is caused by a group of parasitic fungi called dermatophytes. Once the disease-causing fungi come into contact with the skin, the organism begins to multiply and an infection develops. Tinea capitis is contagious, and it can spread through skin-to-skin contact. Patients may be exposed to the fungi after touching an infected animal, such as a dog, cat, ferret, rabbit, goat, or pig. Patients may also become infected after touching objects (e.g. towels, clothing, or bed linens) with which an infected person or animal has been in contact.
Tinea corporis is a ringworm infection that affects the top layer of skin on the legs, arms, face, and trunk of the body. It causes a red, itchy rash. Anti-fungal medications are applied to the skin to treat the infection.
River blindness (onchocerciasis): River blindness, also called onchocerciasis, is a parasitic infection of the eyes that is caused by a worm called Onchocerca volvulu. The disease is transmitted to humans by biting black flies (called Buffalo gnats). When these flies bite a human, they allow the parasitic larvae to enter the human's body.
Once inside the human, the larvae begin to mature into adults. Adults then produce millions of tiny worms, called microfilaria, which migrate throughout the body. River blindness often causes severe itching of the skin, and if left untreated, it may lead to blindness.
River blindness is considered an epidemic in more than 25 countries across the central part of Africa. According to the World Health Organizations' export committee on river blindness, about 18 million people are infected with the parasite each year worldwide. Of those infected, an estimated 6.5 million suffer from severe itching or dermatitis, 500,000 suffer serious visual impairment, and 270,000 are blind.
Scabies: Scabies is a contagious skin disease that is caused by microscopic mites that live three to four weeks in a person's skin. The female mite burrows into skin surface to lay her eggs. These eggs cause an inflammatory response in the host that causes itching, redness, and mild swelling.
Scabies is often spread through direct or prolonged skin contact with an infected person or animal. It is easily spread through direct contact with sexual partners or family members. It may also be spread after sharing clothes, towels, bedding, or other linens, with an infected person.
According to the American Academy of Dermatology, about 300 million cases of scabies are reported each year worldwide. It is most common among schoolchildren, individuals living in crowded areas, and people living in poverty.
Tapeworm infection: A tapeworm infection is a parasitic infection that affects the digestive tract.
Humans become infected with tapeworms after they consume food or water that is contaminated with tapeworm larvae. Most tapeworm infections in humans are caused by the pork tapeworm (Taenia solium), the dwarf tapeworm (Hymenolepis nana), the beef tapeworm (Taenia saginata), or the fish tapeworm (diphyllobothrium latum). Tapeworm infections typically occur when a person consumes food, water, or soil that is contaminated with human or animal feces.
Most tapeworm infections cause no symptoms. However, if symptoms do occur, patients typically experience abdominal pain, bloating, nausea, and diarrhea.
Tapeworm infections that are limited to the intestines can be successfully treated with anti-helminthic medications.
Cooking meat thoroughly kills the parasites and prevents an infection from occurring. The meat must reach at least at least 150 degrees Fahrenheit in order to ensure that any tapeworm eggs and larvae have been killed.
Threadworm infection: Threadworm infection, also called strongyloidiasis, is a parasitic infection of the intestines that is caused by a type of roundworm called Strongyloides stercoralis. Unlike the more common roundworm infection ascariasis, a threadworm infection may also spread to the skin.
The infection is transmitted to humans when a person comes into contact with soil that is contaminated with S. stercoralis. This usually occurs when an individual walks barefoot on soil. The larvae enter the human through the skin. Once inside the body, they migrate to the lymph nodes where they are carried into the lungs. Once in the lungs, the larvae migrate to the patient's throat. When the patient coughs, the larvae are swallowed and they enter the digestive tract. Once in the intestine, the larvae mature into egg-producing adults. The eggs are then released in the patient's feces.
Adult threadworm may grow to be one to two inches long.
Threadworm infections are not fatal. However, if left untreated, threadworm infections can last for as long as 45 years.
Although this infection can occur in most areas of the world, it is most prevalent in tropical and subtropical climates.
Trichinosis: Trichinosis is a type of parasitic infection that is caused by the roundworm Trichinella. Humans become infected when they eat undercooked meat (usually beef or pork) that is contaminated with Trichinella larvae.
Once inside the human, the larvae mature in the intestine into adult worms over the course of several weeks. The adults then produce larvae that migrate to various body tissues, including muscle.
Some patients may have mild, if any, symptoms. However, if the patient is infected with hundreds of worms, it may lead to permanent tissue damage. This is because the larvae burrow into the patient's muscle and other tissues in the body.
The United States Centers for Disease Control (CDC) recommends cooking meat products until the juices run clear or to an internal temperature of 170 degrees Fahrenheit in order to kill Trichinella larvae.
Whipworm infection: Whipworm infection occurs when a parasitic worm, called Trichocephalus trichiura, infects the large intestine. This infection primarily affects children.
Humans become infected after they consume foods that are contaminated with soil that contains whipworm eggs. Once inside the body, the eggs hatch and attach themselves to the wall of the large intestine.
Whipworms are found around the world, especially in countries with warm and humid weather.