Strongyloidiasis

Strongyloidiasis is an infection with the roundworm Strongyloides stercoralis (S stercoralis).

Causes

S stercoralis is a roundworm that is fairly common in warm, moist areas. In rare cases, it can be found as far north as Canada.

People catch the infection when their skin comes in contact with soil that is contaminated with the worms.

The tiny worm is barely visible to the naked eye. Young roundworms can move through a person's skin and eventually into the bloodstream to the lungs and airways.

They then move up to the throat, where they are swallowed into the stomach. From the stomach, the worms move to the small intestine, where they attach to the intestinal wall. Later, they produce eggs, which hatch into tiny larvae (immature worms) and pass out of the body.

Unlike other worms, these larvae can re-enter the body through the skin around the anus, which allows an infection to grow. Areas where the worms go through the skin can become red and painful.

This infection is uncommon in the United States, but it does occur in the southeastern US. Most cases in North America are brought by travelers who have visited or lived in South America or Africa.

Some people are at risk for a severe type called strongyloidiasis hyperinfection syndrome. In this form of the condition, there are more worms and they multiply more quickly than normal. It can occur in people who have a weakened immune system. This includes people who have had an organ or blood-product transplant, people with HIV/AIDS, and those who take steroid medicine or immune-suppressing drugs.

Symptoms

Most of the time, there are no symptoms. If there are symptoms, they may include:

• Abdominal pain (upper abdomen)

  Abdominal pain

  Abdominal pain is pain that you feel anywhere between your chest and groin. This is often referred to as the stomach region or belly.

  

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• Cough
• Diarrhea

  Diarrhea

  Diarrhea is when you pass loose or watery stool.

  

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• Rash
• Red hive-like areas near the anus
• Vomiting
• Weight loss
• Fever

Exams and Tests

The following tests may be done:

• Blood tests such as complete blood count with differential, eosinophil count (a type of white blood cell), antigen test for S stercoralis

  Complete blood count

  A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...

  

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  Eosinophil count

  An absolute eosinophil count is a blood test that measures the number of one type of white blood cells called eosinophils. Eosinophils become active...

  

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• Duodenal aspiration (removing a small amount of tissue from the first part of the small intestine) to check for S stercoralis (uncommon)

  Aspiration

  Aspiration means to draw in or out using a sucking motion. It has two meanings:Breathing in a foreign object (for example, sucking food into the air...

  

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• Sputum culture to check for S stercoralis

  Sputum culture

  Routine sputum culture is a laboratory test that looks for germs that cause infection. Sputum is the material that comes up from air passages when y...

  

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• Stool sample exam to check for S stercoralis

  Stool sample exam

  Stool ova and parasites exam is a lab test to look for parasites or eggs (ova) in a stool sample. The parasites are associated with intestinal infec...

  

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Treatment

The goal of treatment is to eliminate the worms with anti-worm medicines, such as ivermectin or albendazole.

Sometimes, people with no symptoms are treated. This includes people who take drugs that suppress the immune system, such as those who are going to have, or have had, a transplant.

Outlook (Prognosis)

With proper treatment, the worms can be killed and full recovery is expected. Sometimes, treatment needs to be repeated.

Infections that are severe (hyperinfection syndrome) or that have spread to many areas of the body (disseminated infection) often have a poor outcome, especially in people with a weakened immune system.

Possible Complications

Possible complications include:

• Disseminated strongyloidiasis, particularly in people with HIV or an otherwise weakened immune system
• Strongyloidiasis hyperinfection syndrome, also more common in people with a weakened immune system
• Eosinophilic pneumonia

  Eosinophilic pneumonia

  Simple pulmonary eosinophilia is inflammation of the lungs from an increase in eosinophils, a type of white blood cell. Pulmonary means related to t...

  

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• Malnutrition due to problems absorbing nutrients from the gastrointestinal tract

  Malnutrition

  Malnutrition is the condition that occurs when your body does not get enough nutrients.

  

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When to Contact a Medical Professional

Contact your health care provider for an appointment if you have symptoms of strongyloidiasis.

Prevention

Good personal hygiene can reduce the risk of strongyloidiasis. Public health services and sanitary facilities provide good infection control.