What Are Intestinal Worms? Causes, Symptoms & Treatment
Intestinal worm infections are often misunderstood. This guide provides a clear perspective on how they are acquired and why a medical diagnosis is essential.
Intestinal worms, or parasitic helminths, are multi-celled organisms that live in the human gastrointestinal tract and get nourishment from their host. These infections are widespread globally, especially in tropical and subtropical regions, but can happen anywhere. Although a common health issue, intestinal worms are treatable with modern medical care.
Common Types of Intestinal Worms
Pinworms, scientifically known as Enterobius vermicularis, are the most frequent intestinal worm infection in the United States, especially among school-aged children. These parasites are small, thin, white roundworms resembling a piece of thread. The lifecycle occurs entirely within human hosts, where female worms migrate to the anal region at night to lay thousands of eggs, causing intense itching and facilitating transmission through direct contact or contaminated surfaces.
Ascaris lumbricoides, a type of roundworm, is one of the most common parasitic infections worldwide. These worms are significantly larger than pinworms, with adult females reaching lengths of 20-35 centimeters. Infection results from ingesting eggs present in soil contaminated by human feces, often through unwashed fruits or vegetables. Once ingested, the larvae hatch, penetrate the intestinal wall, travel to the lungs, and are then coughed up and swallowed, returning to the intestine to mature.
Tapeworms are flat, segmented worms that attach themselves to the intestinal wall and can grow to be several meters long. Human infections occur from consuming undercooked or raw meat from infected intermediate hosts, such as pork (Taenia solium), beef (Taenia saginata), or fish. The larval cysts present in the animal’s muscle tissue develop into adult worms in the human intestine.
Hookworms are named for the hook-like bend they use to attach firmly to the wall of the small intestine. These parasites, about 1 centimeter long, feed on the host’s blood, which can lead to anemia in cases of heavy infestation. Infection occurs when larval forms in contaminated soil penetrate the skin, usually when a person walks barefoot. From the skin, they travel through the bloodstream to the lungs and are eventually swallowed, maturing in the small intestine.
Risk Factors
Certain factors increase an individual’s susceptibility to intestinal worm infections. Living in or traveling to regions with poor sanitation and limited access to clean water elevates the risk considerably. Children are often more vulnerable due to their playing habits, such as playing in soil, and less consistent hand hygiene. Individuals with weakened immune systems may also face a higher risk of contracting these parasites.
Recognizable Signs and Symptoms
Symptoms of an intestinal worm infection include persistent abdominal pain, bloating, gas, and nausea. Some people may also experience chronic diarrhea, unexplained fatigue, or unintentional weight loss as parasites consume nutrients.
Specific signs can point to the type of worm. A primary symptom of a pinworm infection is intense itching around the anal area, which worsens at night. In some cases, worms may be visible in the stool, appearing as small, white pinworms or larger roundworms.
Symptom severity is related to the worm burden, which is the number of parasites present. Infections with a low worm burden may produce no noticeable symptoms. Severe or long-term infections can lead to complications like intestinal obstruction or anemia from blood loss.
Medical Diagnosis and Treatment
If you suspect an intestinal worm infection, a medical evaluation is necessary. A physician will perform a physical exam and discuss symptoms, travel history, and lifestyle factors. The primary diagnostic tool is a stool test, also known as an “ova and parasite” test, where a lab analyzes a sample to identify worm eggs or parasites.
For pinworms, a doctor might use a “tape test.” This involves placing a piece of clear adhesive tape against the skin around the anus first thing in the morning before bathing. The tape is then examined under a microscope for pinworm eggs.
In some situations, a blood test may be ordered to check for an elevated level of eosinophils, a type of white blood cell that can indicate a parasitic infection.
The standard treatment is prescription antiparasitic medication. The choice of drug, such as praziquantel for tapeworms or albendazole for roundworms and hookworms, and the length of treatment are determined by the specific type of worm identified.