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The string test, also known as the Entero-test, is a diagnostic procedure used to detect parasites in the upper part of the gastrointestinal tract.
When Is a String Test Necessary?
A doctor may order a string test if they suspect an intestinal parasite infection. Typically, a stool sample is tested first. If the stool sample results are negative but symptoms persist, a string test may be performed.
How the String Test Is Performed
The test uses a weighted gelatin capsule with an attached string. The process follows these steps:
- One end of the string is taped to your cheek.
- You swallow the capsule.
- The string remains in place for 4 to 6 hours or overnight.
- You must not eat anything while the string is in place.
- The string is removed and examined under a microscope for signs of parasites.
Symptoms of Intestinal Parasites
Some parasites can live in the intestines for years without causing any symptoms. When symptoms do occur, they may include:
- Diarrhea, nausea, or vomiting
- Bloating and gas
- Loose stools containing blood and mucus
- Stomach pain or tenderness
- Weight loss and tiredness
- Visible worms in the stool
- Itching or a rash around the rectum
Causes and Transmission
Intestinal parasites usually spread through fecal-to-oral transmission, which occurs when tiny amounts of fecal matter are swallowed. Common transmission methods include:
- Eating raw fruits or vegetables washed in contaminated water
- Eating raw shellfish grown in contaminated water
- Drinking water contaminated with raw sewage
- Swimming in contaminated pools, lakes, or ocean waters
- Sexual activity involving mouth-to-anus contact
Common Types of Intestinal Parasites
While more common in undeveloped regions, several parasites are prevalent in the United States:
- Enterobius vermicularis (Pinworm): The most common parasite in the U.S., especially in children. Over 30% of children worldwide are infected. It causes itching around the vagina and anus.
- Giardia lamblia: The most common intestinal infection globally and the second most common in the U.S. Often called “backpacker’s diarrhea,” it survives in cold mountain streams. Symptoms typically appear 1 to 2 weeks after exposure.
- Ancylostoma duodenale and Necator americanus (Hookworms): These live in the small intestines. Most infestations are asymptomatic, but the most serious complication is anemia caused by blood loss.
- Entamoeba histolytica: Causes amebiasis. It is rare in the U.S. but occurs in people who have immigrated from or traveled to parts of Asia, Africa, and Latin America. It spreads quickly through contaminated water in crowded, unsanitary conditions.
Risk Factors
You are at a higher risk of contracting intestinal parasites if you:
- Have HIV/AIDS or a weakened immune system
- Are very young or elderly
- Travel internationally or live in an area where parasites are common
- Have poor hygiene or access unsanitary food and water
- Are in child care centers or institutional care
Treatment Options
Treatment depends on the specific parasite causing the infection:
- No treatment: Some infections resolve on their own.
- Antiparasitic medicines: Used to eliminate the parasite or reduce the worm count until symptoms clear.
- Antibiotics and antifungals: Used to treat other specific types of parasites.
Prevention Guidelines
To reduce your risk, follow these practices:
- Avoid drinking untreated water from streams or lakes.
- Avoid swallowing water in pools or water parks.
- Ensure all food is adequately cooked and water is uncontaminated.
- When traveling to high-risk areas, avoid tap water and follow the “Cook it, boil it, peel it, or forget it” rule.
Handwashing is essential:
- Before eating and during/after food preparation.
- After using the toilet or changing a child’s diaper.
- Before and after treating a wound or caring for a sick person.
- After touching animals or animal waste.
FAQ
What is the “backpacker’s diarrhea” parasite?
Giardia lamblia is nicknamed “backpacker’s diarrhea” because it survives well in cold mountain streams and frequently infects people who spend significant time outdoors.
How common are pinworms in children?
Pinworms (Enterobius vermicularis) are the most common intestinal parasite in the United States, and over 30% of children worldwide are infected.
What is the most serious complication of a hookworm infection?
The most serious complication associated with hookworms (Ancylostoma duodenale and Necator americanus) is anemia resulting from blood loss.
Medical Disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
approved by: Medica Health team (demo)