Worm infections: what to watch for and what to do

Ever had unexplained stomach pain, itchy anus at night, or sudden weight loss after travel? Those can be signs of a worm infection. Worms (parasitic helminths) still affect people worldwide, but most are treatable once diagnosed. This page gives clear, practical steps to spot infections, get tested, and avoid reinfection.

Common types and symptoms

Different worms cause different problems. Pinworms (Enterobius) give intense anal itching, especially at night. Roundworms (Ascaris) can cause stomach pain, coughing, and sometimes intestinal blockage. Hookworms may lead to anemia and tiredness. Tapeworms often cause weight loss and vague belly discomfort after eating undercooked meat or fish. Schistosoma (blood flukes) cause blood in urine or stool and can affect the liver or bladder.

Watch for these signs: persistent diarrhea, belly pain, unexplained weight loss, fatigue, coughing without a clear cause, itchy bottom, or visible worms in stool. If you’ve recently traveled, swam in freshwater in tropical areas, or eaten raw/undercooked meat or fish, tell your clinician—those are big clues.

How doctors diagnose and treat worm infections

Diagnosis usually starts with stool tests. Labs look for eggs or larvae in one or more stool samples—sometimes you need multiple tests because results can miss infections. For pinworms, a simple “tape test” (sticky tape at the anus in the morning) often finds eggs. Blood tests can show high eosinophils (a sign your body is reacting to parasites) or antibodies for specific worms. Imaging or endoscopy may be needed in complicated cases.

Treatment depends on the worm type. Albendazole and mebendazole are common for pinworms and many roundworms. Praziquantel is the go-to for tapeworms and schistosomiasis. Ivermectin is used for some parasites like strongyloides. Your doctor will pick the right drug and dose. Often household members are treated at the same time to stop reinfection.

Simple home measures matter: wash hands after using the toilet and before eating, keep fingernails short, wash bedding and clothes in hot water if someone is infected, and avoid walking barefoot in areas where hookworm is common. Cook meat and fish thoroughly and drink safe water when traveling. Deworm pets regularly—pets can carry some types of worms that affect people.

When to see help? Get medical care for persistent gastrointestinal symptoms, blood in stool, heavy itching, unusual cough, sudden weight loss, or if a child shows poor growth. Early testing and the right medicine fix most infections quickly.

If you’re worried about a specific exposure—travel, food, or a sick pet—reach out to a clinician and mention those details. That makes testing faster and treatment more accurate. With the right steps, you can clear the infection and stop it coming back.