Roundworm Symptoms in Humans

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Roundworms are parasitic invertebrates that can inhabit the human body, primarily living in the intestines. The six most common types of roundworms include pinworms, ascaris, hookworms, whipworms, strongyloides and trichinella spiralis. Roundworms vary in size, transmission and habitat. Though most roundworm infections are not life threatening in healthy people, many cause uncomfortable and sometimes serious symptoms.


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The pinworm is the most common roundworm in the United States. It is small and threadlike and infests many more children than adults.

The ascaris roundworm thrives in the intestinal tract of mammals and can range in length from six to thirteen inches. Toxocara, a type of ascarid, typically infects domestic animals such as dogs and cats, and can be spread to humans.

Hookworms, whipworms and strongyloides are found primarily in tropical and subtropical countries. They thrive in moist soil or human feces.

Roundworms that cause trichinosis are found mainly in the digestive tracts of pigs that consume garbage.


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Pinworm eggs are found in the human colon and rectum. They are transmitted when an infected host scratches the area and touches other people, food, or objects.

The ascaris roundworm is transmitted mainly through feces and is thus prevalent in areas with poor sanitation. Humans become infected from touching infected dog or cat feces and then touching food or their mouths.

Hookworms, whipworms and strongyloides travel from feces to moist soil. When a human walks over contaminated soil barefoot, the worms attach to the feet and penetrate the skin, making their way to the digestive tract.

Humans become infected with trichinosis after eating undercooked contaminated pork products. The parasite thrives in the muscle fibers of the intestines.


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The effects of a roundworm infection are not usually life threatening. People with a pinworm infection may not experience symptoms, while others will encounter mild to intense anal and/or vaginal itching.

Symptoms of an ascariasis infection range from mild abdominal pain to sharp abdominal pain, restlessness and vomiting. The severity of symptoms depends on the number of worms in the intestinal tract.

The hookworm, whipworm and strongyloides can cause an itchy, allergic reaction at the entry site. When the hookworm larvae migrate to the intestine, symptoms of diarrhea, abdominal pain, colic, nausea and cramps are common. Many people do not experience any symptoms from a whipworm. However, severe infections may cause bloody stools, weight loss, stomach pain and diarrhea. A mild strongyloides infection usually does not have symptoms. Moderate infections can cause vomiting, diarrhea or constipation.

A mild trichinosis infection usually produces no symptoms or light stomachaches and joint and/or muscle pain. Severe infections can cause muscular rheumatism and symptoms that mirror food poisoning.


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Patients who are pregnant or immunocompromised should take extra precaution after becoming infected by a roundworm. The infection can become chronic and might not clear on its own. A chronic case is likely to cause anemia and weight loss. A chronic strongyloides infection can also cause acute respiratory distress syndrome, which is similar to pneumonia.


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Roundworms can be easily prevented with proper hygiene. Children should be taught to always wash their hands after using the bathroom, or sharing toys with other children. Animals with roundworm infections should be treated, and their feces should be avoided or disposed of properly. A trichinosis infection can be prevented by avoiding undercooked pork products. People handling raw pork products should always wash their hands after exposure. To avoid whipworm, hookworm and strongyloides, proper shoes should be worn over moist ground.