Ascariasis
About- Ascariasis is a common intestinal infection caused by the parasitic roundworm Ascaris lumbricoides. The adult worms live in the small intestine, where they feed on intestinal contents and produce eggs that are passed out of the body through stool. The infection occurs when a person accidentally swallows Ascaris eggs, usually through contaminated soil, food, water, or unwashed fruits and vegetables. Ascariasis is more common in areas where sanitation and access to clean water are limited. Many people with a mild infection have no symptoms. However, a heavy infection can cause abdominal problems, nutritional deficiencies, intestinal blockage, and other complications. During part of its life cycle, the Ascaris larvae travel through the lungs, which may temporarily cause coughing, wheezing, or breathing difficulties. Ascariasis can usually be treated effectively with antiparasitic medicines prescribed or recommended by a healthcare professional.
Many people with ascariasis do not develop noticeable symptoms, particularly when the infection is mild. Symptoms are more likely when there are many worms or when the larvae are passing through the lungs. Possible symptoms include:
- Coughing
- Wheezing
- Shortness of breath
- Loss of appetite
- Worms in the stool
- Nausea and vomiting
- Abdominal pain or discomfort
- Diarrhoea
- Irregular bowel movements
- Fever
- Chest discomfort
- Blood-streaked mucus or blood in mucus in some cases
- Unexplained weight loss
- Poor nutrition
- Delayed growth in children
After a person swallows Ascaris eggs, the larvae hatch in the intestine and can travel through the bloodstream to the liver and then to the lungs. The larvae may enter the airways and eventually be swallowed again, returning to the intestine. During this stage, some people may develop:
- Dry cough
- Wheezing
- Shortness of breath
- Chest discomfort
- Fever
- Blood-streaked mucus
These symptoms are generally temporary but may be more noticeable in people with a larger number of larvae.
Once the worms mature in the small intestine, they may cause:
- Abdominal pain or cramping
- Nausea
- Vomiting
- Loss of appetite
- Diarrhoea or irregular bowel movements
- Weight loss
- Visible worms in the stool
A heavy worm burden can sometimes interfere with the normal movement of food through the intestine.
Ascariasis occurs when a person swallows infectious Ascaris lumbricoides eggs. The eggs are passed in the stool of an infected person. If human faeces contaminate soil or water, the eggs can remain in the environment and eventually contaminate food or people’s hands. Common ways of becoming infected include:
- Contact with soil contaminated with human faeces containing Ascaris eggs
- Drinking contaminated water
- Eating food contaminated with Ascaris eggs
- Eating unwashed fruits or vegetables grown in contaminated soil
- Handling contaminated soil and then touching the mouth without washing the hands
- Children playing in contaminated soil and putting dirty fingers or objects into their mouths
The infection does not usually spread directly from one person to another simply through casual contact. The eggs generally need to mature in contaminated soil before they become capable of causing infection.
The life cycle of Ascaris lumbricoides helps explain how infection develops.
- An infected person passes Ascaris eggs in their stool.
- The eggs contaminate soil when sanitation systems are inadequate.
- Under suitable environmental conditions, the eggs become infectious.
- A person accidentally swallows the infectious eggs through contaminated food, water, hands, or soil.
- The eggs hatch in the small intestine.
- The larvae travel through the body and eventually reach the lungs.
- The larvae move up the airways and are swallowed.
- They return to the small intestine, where they mature into adult worms.
- Adult worms produce eggs, which are passed out in the stool, continuing the cycle.
Certain conditions can increase the likelihood of developing ascariasis. Risk factors include:
- Living in or travelling to areas where ascariasis is common
- Poor sanitation
- Limited access to safe drinking water
- Inadequate sewage disposal
- Frequent contact with contaminated soil
- Eating raw or poorly washed fruits and vegetables
- Poor hand hygiene
- Children playing in contaminated soil
- Eating food prepared with contaminated hands
Children may be particularly vulnerable because they are more likely to play in soil and put their fingers or objects in their mouths.
Most cases of ascariasis can be treated successfully. However, a heavy infection can sometimes cause serious complications. Possible complications include:
A large number of adult worms can form a mass that blocks the intestine. This may cause severe abdominal pain, vomiting, abdominal swelling, and difficulty passing stool or gas.
In rare and severe cases, intestinal complications may lead to a hole in the intestinal wall. This is a medical emergency.
Adult worms may occasionally migrate into the bile ducts or pancreatic ducts. This can cause inflammation, abdominal pain, jaundice, or pancreatitis.
A heavy infection can interfere with normal nutrition and may contribute to poor growth or weight loss, particularly in children.
Repeated or heavy infections in children may contribute to poor nutritional status and impaired physical development.
During the larval migration stage, some people may develop temporary inflammation in the lungs, sometimes called Löffler syndrome, which can cause cough, wheezing, fever, and abnormal findings on chest imaging.
A healthcare professional may suspect ascariasis based on symptoms, medical history, travel or living conditions, and exposure to contaminated soil or food.
A stool test is commonly used to identify Ascaris eggs under a microscope. Several stool samples may sometimes be needed because eggs may not be present in every sample.
In some cases, an adult worm may be noticed in the stool or may be passed through the mouth or nose. If this happens, medical evaluation is recommended.
Blood tests may sometimes show an increased number of eosinophils, a type of white blood cell that can increase with certain parasitic infections. However, this finding is not specific to ascariasis.
If complications are suspected, a doctor may recommend tests such as an ultrasound, X-ray, CT scan, or other imaging studies to look for intestinal or biliary obstruction.
Ascariasis is generally treated with antiparasitic medicines. Commonly used medicines include albendazole and mebendazole, depending on the patient’s age, health status, pregnancy status, local treatment recommendations, and other factors. Treatment should be taken according to the advice of a qualified healthcare professional. In some cases, a follow-up stool examination may be recommended to determine whether the infection has cleared.
If a large number of worms cause an intestinal or biliary obstruction, additional treatment may be required. Severe complications may occasionally require an endoscopic procedure or surgery. Do not self-medicate with antiparasitic medicines, particularly for young children or during pregnancy, without appropriate medical advice.
Good sanitation and personal hygiene are important for preventing ascariasis. You can reduce the risk of infection by:
- Washing your hands thoroughly with soap and clean water after using the toilet and before preparing or eating food
- Washing children’s hands regularly
- Washing fruits and vegetables carefully before eating them
- Peeling or cooking fruits and vegetables when appropriate
- Avoiding food or water that may be contaminated
- Using safe drinking water
- Avoiding contact with human faeces
- Using proper toilets and sanitation facilities
- Disposing of human waste safely
- Keeping children’s play areas away from contaminated soil
- Avoiding putting dirty fingers or objects into the mouth
In areas where intestinal worm infections are common, community-wide deworming programmes may be recommended for certain populations, particularly children, according to local public-health guidelines.
Consult a healthcare professional if you have persistent abdominal pain, unexplained weight loss, recurrent digestive symptoms, or believe that you may have a parasitic infection. Seek urgent medical attention if you develop:
- Severe or worsening abdominal pain
- Persistent vomiting
- Severe abdominal swelling
- Inability to pass stool or gas
- Yellowing of the skin or eyes
- Severe breathing difficulty
- Coughing up significant amounts of blood
- Signs of a serious intestinal obstruction
Children with suspected ascariasis should be evaluated by a healthcare professional, particularly if they have poor growth, persistent abdominal symptoms, or evidence of worms in their stool.
Ascariasis is an intestinal infection caused by the parasitic roundworm Ascaris lumbricoides. The adult worms live mainly in the small intestine.
People become infected by swallowing infectious Ascaris eggs. The eggs may be present in contaminated soil, food, water, or on unwashed hands and produce.
Yes. During the early stage of infection, Ascaris larvae can migrate through the lungs. This may cause coughing, wheezing, chest discomfort, or shortness of breath.
Yes. Adult Ascaris worms can sometimes be visible when they are passed in the stool. If you notice a worm in your stool, consult a healthcare professional for identification and treatment.
Ascariasis does not usually spread through ordinary person-to-person contact. Infection generally occurs when someone swallows infectious eggs that have matured in contaminated soil or on contaminated food, water, or hands.
Yes. Children can be particularly susceptible because they may frequently play in soil and put their hands or objects into their mouths. Poor sanitation and hygiene can further increase the risk.
Heavy or repeated intestinal worm infections can contribute to nutritional problems and may affect growth and development. Children with suspected infection should receive appropriate medical evaluation and treatment.
Yes. Ascariasis can generally be treated effectively with antiparasitic medicines. Treatment may vary depending on the patient’s age, health, pregnancy status, and severity of infection.
Yes. Treatment eliminates the existing infection but does not necessarily prevent a person from becoming infected again. Good sanitation, hand hygiene, safe food and water, and appropriate public-health measures help reduce reinfection.
Most infections do not cause severe complications, but a heavy worm burden can occasionally cause intestinal obstruction or migration of worms into the bile or pancreatic ducts. These complications require medical attention.
Ascariasis can often be diagnosed and treated by a general physician or primary-care doctor. An infectious disease specialist may be consulted in complicated or unusual cases.
- Ascariasis is caused by the roundworm Ascaris lumbricoides.
- Infection occurs when infectious eggs are swallowed.
- Contaminated soil, food, water, and poor hand hygiene can contribute to transmission.
- Many people have no symptoms.
- Lung migration can cause temporary cough, wheezing, or breathing difficulties.
- Intestinal infection can cause abdominal pain, nausea, diarrhoea, appetite changes, and weight loss.
- Heavy infections can occasionally cause intestinal or biliary obstruction.
- Antiparasitic medicines can usually treat the infection effectively.
- Good sanitation, handwashing, safe water, and properly washed food help prevent infection.
If you are concerned about ascariasis, consult a General Physician/Primary Care Doctor. An Infectious Disease Specialist may be appropriate for complicated, recurrent, or unusual infections.
Infectious Disease Specialist
This article is intended for general informational and educational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Symptoms can vary from person to person, and similar symptoms may occur with other medical conditions. If you suspect that you or your child has ascariasis, consult a qualified healthcare professional for proper evaluation and treatment. Do not start, stop, or change any medication without medical advice. Seek urgent medical attention for severe abdominal pain, persistent vomiting, breathing difficulty, or other serious symptoms.
