Healthy Living

What Are Roundworms?

What Are Roundworms

What are roundworms?

Roundworms are a type of parasitic worms that infect the human intestine. Roundworms may vary and size and have a characteristic long, round body. These parasitic worms can cause a number of health problems in humans. They can enter the human body through the mouth and direct contact with contaminated soil and stool. Roundworms can also survive in the intestine for a long time. 

Roundworms or nematodes belong to the phylum Nematoda. Roundworms are contagious and anyone can get a roundworm infection. However, this parasitic infection is more commonly seen in people who live in underdeveloped parts of the world, especially in tropical and subtropical areas. Individuals with poor hygiene are also susceptible to contract parasitic infections. 

There are several types of roundworm infections, which can cause nausea, diarrhea, abdominal pain, weight loss, breathing difficulty, and blood in the stool. 

Characteristics of Roundworms

Nematodes are different in many ways. They also live in different environments. For instance, if they live in an environment with a low food supply, they tend to become hermaphrodites, which means that they both have male and female parts and are capable of self-fertilizing and carrying their eggs until they hatch. 

They also have the following similar characteristics:

  • Microscopic
  • No backbone or invertebrates
  • Get nutrients and breathe through diffusion
  • Appear slender and elongated (snake-like appearance)
  • Have a flexible but rigid outer layer 
  • Whip-like movements
  • Able to detect certain chemicals and light
  • Possess a sense of touch

Types of Roundworms

1. Ascaris (Ascaris lumbricoides)

Ascaris lumbricoides is the largest roundworm that parasitizes the human intestine. An adult female can be as long as 35 cm, while an adult male can grow up to 30 cm. People with A. lumbricoides are often asymptomatic with mild intestinal discomfort at times. If the infestation is severe, these large roundworms can block the intestine. They can also cause wheezing and coughing if immature roundworms reach the lungs. The disease caused by this roundworm is called ascariasis, which is uncommon in the United States. 

2. Hookworms (Ancylostoma duodenale and Necator americanus)

A. duodenale and N. americanus are two major types of hookworms. Hookworm eggs usually end up in the soil after human defecation. Their eggs hatch in soil and become tiny immature worms until they have the opportunity to enter the human body by breaking through the skin like the soles of the feet when people walk barefoot. 

These worms travel to the human intestines, where they mature. Hookworms can also potentially cause anemia because they tend to attach to the intestinal lining and suck blood. Hookworm infections in humans are uncommon in the United States. 

Another type of hookworm is Ancylostoma braziliense, which causes a human skin disease called cutaneous larva migrans (CLM).

3. Pinworm (Enterobius vermicularis)

Pinworm is also called seatworm or threadworm and is one of the most common human intestinal parasites. The infection caused by pinworms is called enterobiasis. These worms are small and can easily spread. According to the Centers for Disease Control and Prevention (CDC), pinworms are the most common type of human intestinal worms in the U.S.

Enterobiasis is usually seen in children ages 5-10 years old. This parasitic infection is also common in people who have direct contact with these children and those who live in institutions. Treatment for enterobiasis includes medication. Although long-term health effects and dangerous complications are rare, reinfection is possible. 

4. Strongyloides (Strongyloides stercoralis, S. fülleborni)

The disease caused by Strongyloides worms is called Strongyloidiasis. Strongyloides also live in the soil and infect humans by breaking through the skin. Similar to hookworms, they also attach to the intestinal lining of humans. Strongyloidiasis have been reported in the Southeast, while tends to be rare in the U.S. This parasitic infection causes mild symptoms, but may also cause any of the following:

5. Trichinella (Trichinella spiralis)

Rats and rodents are usually responsible when it comes to the endemicity of this parasitic infection. Game meat and pigs become hosts of Trichinella when they feed on the infected meat of other animals and rodents. Humans can also get infected when they accidentally consume the undercooked meat of infected animals. 

The disease caused by Trichinella is called trichinellosis, which may cause mild to severe symptoms. After 1-2 days of consuming infected meat, diarrhea, nausea, and vomiting may occur. After two weeks, fever, headache, and muscle pain may be experienced. 

6. Whipworm (Trichuris trichiura)

Like Ascaris and hookworms, whipworm is also soil-transmitted. Whipworms usually inhabit the large intestine. Their eggs are then passed in the feces of infected humans. These eggs become infective when they become in contact with soil. This happens when infected humans defecate outside near a garden, field, or bushes. The eggs can also be deposited in the soil when infected human feces is used as a soil fertilizer. 

This parasitic infection occurs when whipworm eggs are ingested. Transmission can happen when people eat food without washing their hands or cleaning their fingers that have contaminated dirt, including the consumption of unwashed, raw fruits and vegetables. 

Trichuriasis is the disease caused by whipworms. People with trichuriasis may develop mild to severe infections. Those who only have light infections may not experience symptoms, but those with severe infections may experience frequent diarrhea and passing of stools that contain water, blood, and mucus. Growth retardation and severe anemia can occur in children with heavy infections. However, trichuriasis can be treated with prescribed medication. 

Diagnosis and Treatment

Roundworm infections are diagnosed by taking a patient's medical history, along with checking his or her symptoms. Healthcare providers may run some blood tests including a stool analysis to check for the presence of eggs under the microscope. 

Albendazole is the most commonly prescribed medication for the treatment of roundworm infections. Other treatments may involve the use of iron supplements and creams to help relieve anal itching or pain. In some cases, roundworm treatments are repeated after several weeks to completely get rid of the eggs. 


Roundworm infections can be prevented in the following ways:

  • Practice good handwashing habits using soap and water, especially after doing outdoor activities, such as gardening or playing with your pets. 
  • Always clean up after your pets.
  • Make sure that your pets are periodically dewormed. 
  • Strictly teach your children not to play outside near animal stools.
  • Teach your children good handwashing habits and not to eat soil or dirt.