Worms are parasitic organisms that can live inside the bodies of humans and animals. There are several different types of worms that can infect people, with the most common being roundworms, tapeworms, whipworms, hookworms, pinworms, and trichinosis worms.
While most worm infections do not cause serious harm, some worms can lead to health problems if left untreated. Understanding the risks and how to prevent worm infections is important for protecting your health.
What are the most common worms that infect humans?
Here are some of the most prevalent worm parasites that can live in the human body:
- Roundworms – Roundworms are long, thin worms that look like strands of spaghetti. The most common is the large roundworm Ascaris lumbricoides, which infects up to 25% of the world’s population. Roundworm eggs are passed in infected feces and can contaminate soil, food, or water. After being swallowed, the eggs hatch in the intestines and the larvae penetrate the intestinal wall to travel through the bloodstream to the lungs. From there they ascend the respiratory tract to the throat where they are swallowed again, allowing them to mature into adults in the intestines. Roundworm infection is called ascariasis.
- Tapeworms – Tapeworms are flat, segmented worms that attach themselves to the intestinal walls. The most frequent offender is the pork tapeworm Taenia solium. Tapeworm larvae enter the body when people ingest contaminated pork, beef, or fish. The worms then latch onto the intestines with hook-like mouthparts. As the tapeworms grow, their segments containing eggs break off and pass into feces. Tapeworm infection is called taeniasis.
- Whipworms – Whipworms earned their name from their whip-like shape. They live in the large intestine. Humans can become infected by ingesting microscopic whipworm eggs from soil contaminated with feces. Inside the intestines, the larvae hatch and burrow into the intestinal lining. After maturing, the adult worms emerge from the tissue to live in the intestine. Whipworm infection is known as trichuriasis.
- Hookworms – Hookworms are thin round worms about 1 cm long. The infective larvae live in soil contaminated with feces. Hookworm infection occurs when the larvae penetrate the skin, often through the feet. They then travel through the bloodstream to the lungs and are coughed up and swallowed. The larvae reach adulthood in the small intestine. Hookworm infection is called ancylostomiasis.
- Pinworms – Pinworms reside in the large intestine and colon. After a female pinworm lays her eggs around the anus, this causes anal itching. When the host scratches the itchy area, the eggs stick under fingernails and can be ingested or transferred to household surfaces or bedding. Once swallowed, the eggs hatch into larvae in the small intestine. After maturing into adults, the pinworms migrate to the colon and reproduce. Pinworm infection is known as enterobiasis.
- Trichinosis worms – Trichinosis is caused by eating undercooked meat containing cysts of the larvae of Trichinella spiralis worms. Once in the stomach, the cysts open and release the larvae, which grow into adult worms that produce more larvae. The larvae burrow into muscle tissue, where they form new cysts. Infection with trichinosis is called trichinosis.
What damage can different worm infections cause?
Many worm infections cause relatively mild symptoms, while some can lead to severe illness and serious impacts if left untreated. Here is an overview of the health effects that can result from common worm parasites:
Roundworms
Roundworm infections are often asymptomatic initially. Light infections may cause some gastrointestinal symptoms like abdominal pain, nausea, diarrhea, or vomiting. Heavy infections can lead to intestinal blockages and impairment in growth and cognitive development in children. Roundworms do not multiply inside humans, so the number of worms tends to be low even with chronic infection.
Tapeworms
Like roundworms, many tapeworm infections do not cause symptoms. Heavier infections may result in abdominal discomfort, malnutrition, weight loss, diarrhea, nausea, or weakness. On rare occasions, tapeworm larvae can migrate to other tissues and cause cysts in organs like the eyes, liver and brain which can lead to more severe disease.
Whipworms
Whipworms often do not produce symptoms. Moderate infections may lead to digestive issues like abdominal pain, diarrhea, blood and mucus in the stool. More serious consequences can include malnutrition, impaired development in children, appendicitis, rectal prolapse, and chronic inflammation of the intestines.
Hookworms
A major risk with hookworms is chronic blood loss leading to iron deficiency, protein deficiency, and anemia. The worms rupture capillaries as they burrow through the intestinal lining and suck blood for nourishment. Heavy infections also cause protein loss and impaired growth and mental development in children.
Pinworms
Some common symptoms of pinworm infection include itching around the anus, disturbed sleep, irritability, and difficulty concentrating. Female worms migrate out of the anus at night laying eggs that cause intense anal itching. However, pinworms do not damage the intestines or cause malnutrition.
Trichinosis worms
Trichinosis can have severe effects due to the larvae encysting in muscle tissue. Mild symptoms include diarrhea, abdominal discomfort, fatigue, nausea, and vomiting. More serious cases lead to facial swelling, fever, chills, muscle pain and weakness, bleeding disorders, heart problems, difficulty breathing, and neurological symptoms like confusion or blurred vision. Death can occur in severe infections.
How can you prevent worm infections?
You can take various precautions to avoid contracting parasitic worms:
- Wash hands thoroughly with soap and warm water before eating or handling food and after using the toilet or changing diapers.
- Wash, peel, or cook fruits and vegetables thoroughly.
- Do not drink or swim in contaminated water sources.
- Cook meat thoroughly to temperatures high enough to kill any worms or larvae.
- Avoid walking barefoot where there is potential contact with contaminated soil.
- Decontaminate soil where feces are used as fertilizer before contact.
- Improve sanitation standards and access to clean drinking water and toilets.
- Take preventive drug treatment if there is high risk of certain worm infections.
- Deworm pets regularly and promptly dispose of their feces.
How are worm infections diagnosed and treated?
There are various methods available for detecting and treating intestinal worms:
Diagnosis
- Microscopic examination of stool samples can detect worm eggs or larvae.
- Blood tests can reveal elevated levels of eosinophils or antibodies associated with worm infections.
- Medical imaging like X-rays or CT scans can identify larger roundworms in intestines or organ damage from migrating larvae.
- Endoscopy procedures allow direct visualization of worms attached to the intestinal lining.
- Biopsy of tissues can reveal encysted larvae.
Treatment
- Several broad-spectrum deworming drugs called anthelmintics are available that are effective against a variety of worms. They include mebendazole, albendazole, pyrantel pamoate, and ivermectin.
- Treatment typically consists of one or several oral doses of medication.
- Antibiotics may be prescribed if secondary bacterial infections are present.
- Nutritional supplementation helps reverse malnutrition associated with worm infections.
- Surgery may be required in rare cases for complications like intestinal blockages from large roundworm infections.
Conclusion
Worm infections affect billions of people globally, but the majority of common intestinal worms do not cause lasting harm or serious illness. However, some worms like hookworms and Trichinella can have detrimental impacts if they heavily colonize the intestines or migrate into tissues. Practicing proper hygiene, thoroughly cooking meats, and preventing contamination of soil and food sources with human feces can limit infection risks. Periodic deworming of pets and livestock also helps break disease transmission cycles. While not usually life threatening, worms can impair nutrition, growth and development in children. So prompt diagnosis and medication treatment are advised when worm infection is suspected.