Ascariasis (as-kuh-RIE-uh-sis) is a type of roundworm infection. These worms are parasites that use your body as a host to mature from larvae or eggs to adult worms and reproduce. Adult worms can be more than a foot (30 centimeters) long.
Ascariasis is one of the most common human worm infections worldwide. Because most people have such mild cases of ascariasis, they have no symptoms. But when your body is infested with hundreds of worms, serious symptoms and complications can occur.
Ascariasis occurs most often in young children and is most prevalent in tropical and subtropical regions of the world — especially in areas where sanitation and hygiene are poor.
Most people infected with ascariasis have no symptoms. Moderate to heavy infestations cause symptoms that may vary, depending on which part of your body is affected.
In the lungs
After you ingest the microscopic ascariasis eggs, they hatch in your small intestine and the larvae migrate through your bloodstream or lymphatic system into your lungs. At this stage, you may experience signs and symptoms similar to asthma or pneumonia, including:
After spending six to 10 days in the lungs, the larvae travel to your throat, where you cough them up and then swallow them.
In the intestines
The larvae mature into adult worms in your small intestine, and the adult worms typically live in the intestines until they die. In mild or moderate ascariasis, the intestinal infestation can cause:
If you have a heavy intestinal infestation — a large number of worms — you may experience:
When to see a doctor
Consult your doctor if you have persistent abdominal pain, diarrhea or nausea.
Ascariasis isn’t spread directly from person to person. Instead, a person has to come into contact with soil mixed with human feces that contain ascaris eggs. In many developing countries, human feces are used for fertilizer or poor sanitary facilities allow human waste to mix with local soil in yards, ditches and fields.
Because small children often play in dirt, infection can occur if they put their dirty fingers in their mouths. Unwashed fruits or vegetables grown in contaminated soil also can transmit the microscopic eggs that cause ascariasis.
Life cycle of a worm
The whole process — from egg ingestion to egg deposits — takes about two or three months. Ascariasis worms can live inside you for a year or two.
Risk factors for ascariasis include:
Mild cases of ascariasis usually don’t cause complications. If you have a heavy infestation, potentially dangerous complications may include:
Your family doctor might refer you to a doctor specializing in disorders of the digestive system (gastroenterologist). You may even need to consult a surgeon if the worms have blocked your intestines.
What you can do
Before your appointment, you may want to write down the answers to the following questions:
What to expect from your doctor
During the physical exam, your doctor may press on certain areas of your abdomen to check for pain or tenderness. He or she may also want a sample of your stool for testing.
In heavy infestations, it’s possible to find worms after you cough or vomit, and the worms can come out of other body openings, such as your mouth or nostrils. If this happens to you, take the worm to your doctor so that he or she can identify it and prescribe the proper treatment.
About two months after you ingest ascariasis eggs, the worms mature and begin laying thousands of eggs a day. These eggs travel through your digestive system and eventually can be found in your stool. To diagnose ascariasis, your doctor will examine your stool for the microscopic eggs and larvae. But eggs won’t appear in stool until at least 40 days after you’re infected. And if you’re infected with only male worms, you won’t have any eggs at all.
Your blood can be tested for the presence of an increased number of a certain type of white blood cell, called eosinophils. Ascariasis can elevate your eosinophils, but so can other types of health problems.
While symptomatic infections usually warrant treatment, infections with no symptoms typically don’t need to be treated. In some cases, ascariasis will resolve on its own. This occurs when there are no male worms to mate with females, and the females eventually die.
Anti-parasite medications are the first line of treatment against ascariasis. The most common are:
These medications work by killing the adult worms. Each medication can be taken as a single dose. Side effects include mild abdominal pain or diarrhea.
In cases of heavy infestation, surgery may be necessary to repair damage the worms have caused and to remove worms. Intestinal obstruction or perforation, bile duct obstruction, and appendicitis are complications that may require surgery.
The best defense against ascariasis is good hygiene and common sense. Follow these tips to avoid infection: