Roundworms are the most common cause of worm infections in humans worldwide. Children in particular are affected. The eggs enter the body via contaminated food and develop into worms. A drug can help. Without treatment, affected people die again and again as a result of complications of the infection. Read more here about the possible symptoms and causes of an infection with roundworms as well as about their prevention, treatment and roundworms are what type of biohazard?.
ICD codes for roundworms: B77
Description of roundworms
Roundworms belong to the roundworms and are distributed worldwide. Male roundworms grow up to 25 centimeters long, females even up to 40 centimeters.
Roundworms are parasites. They live inside another living organism, their host. Although roundworms can mostly feed in multiple organisms, they only reproduce in their definitive host.
Various types of roundworm prefer humans, pigs, dogs or another creature as the main host, which can often be seen from the Latin name. For example, Toxocara canis prefers dogs (canis = Latin for dog). If roundworms occur in humans, it is almost always Ascaris lumbricoides . For him, humans are both the main and final host. Other roundworms can also infect and harm humans, even if they don’t breed inside them. The following table shows which roundworms occur in humans and animals.
| Roundworm | main Host |
| Ascaris lumbricoides | Person |
| Ascaris suum | Pig |
| Anisakis marina | Sea animals |
| Toxocara canis | Dog |
| Toxocara cati | Cat |
Ascariasis
As mentioned above, humans are most commonly infected with roundworms of the Ascaris lumbricoides species infested with Such a worm disease is also known as ascariasis. It is one of the most common worm infections worldwide. Experts estimate that around 760 million to 1.4 billion people are infected with this worm. Many cases are recorded in East Asia, Africa and Latin America in particular. A low standard of living in slums and rural areas favors the spread of roundworms.
Up to 90 percent of children in these areas are infected with roundworm. In industrialized countries, on the other hand, it is usually less than one percent. Since the 1950s, the number of people affected in Central Europe has decreased significantly.
Lifestyle of roundworms
The sexually mature roundworms live in the human small intestine. They are as thick as a pencil and colored pinkish-yellowish. The female roundworms produce around 200,000 eggs a day, which are excreted in the human stool. The eggs ripen best in a warm and humid environment of around 30 degrees. The eggs must first mature outside the body before they are infectious. Therefore, a direct infection from person to person is also impossible.
If the eggs are ingested by humans after two to six weeks through contaminated food, the larvae can hatch in the small intestine and infect their host. To do this, they pierce the wall of the small intestine and reach the liver via the veins.
They then continue to travel along the blood pathways via the right heart to the lungs. At the age of about one week, they break through the vascular system there and settle in the air sacs (alveoli). There they molt once or twice and then reach the pharynx via the bronchi and trachea. There they irritate the mucous membrane and trigger a swallowing reflex. The host swallows the young roundworms and thus transports them through the esophagus into the stomach and finally into the small intestine.
Here the roundworms mature into adult, sexually capable parasites. These roundworms produce the first eggs after they have spent about two to three months in their host. In total, they live to be around 18 months.
Symptoms of roundworms
Roundworms migrate through different regions of the human body during their development. If roundworms cause symptoms, these usually reveal the organ that has just been colonized. A distinction is made between pulmonary ascariasis (affecting the lungs) and intestinal ascariasis (affecting the intestines) and biliary ascariasis (affecting the bile ducts). In the first few days, as long as the roundworms are in the stomach, intestines, blood and liver, the body’s defense cells are activated. At this stage of the disease, roundworms usually do not cause any symptoms.
Roundworms in the lungs
Once in the lungs, the defense reactions can increase significantly: the lungs produce more mucus. The bronchi can become irritated and narrow (bronchospasm). Those affected often suffer from a dry cough and can breathe more poorly. You feel pressure behind your breastbone. Asthma-like attacks can also occur.
These symptoms are often accompanied by a high temperature or a slight fever. Allergic reactions such as skin rashes (urticaria) or facial swelling (angioedema) occasionally occur.
These symptoms usually subside within a week or two.
Roundworms in children sometimes lead to life-threatening pneumonia.
Roundworms in the intestine
The adult roundworms prefer to live in the upper small intestine (jejunum). Symptoms mostly depend on the number of worms. Individual roundworms often cause no symptoms at all or only occasionally cause slight abdominal pain. Unspecific symptoms such as nausea or vomiting are also possible.
If around 100 roundworms live in the small intestine, they can block the intestine (ileus). Those affected suffer from severe, sometimes colicky, abdominal pain and have to throw up. The abdomen is distended and painful to the touch. If the intestinal wall is poorly supplied with blood, it can tear or become inflamed. An intestinal perforation is life-threatening and must be operated on immediately!
Roundworms in children often cause symptoms earlier because of the smaller intestine. The worms also prevent food from being properly digested. Some sufferers develop a protein deficiency as a result.
If roundworms get into the stomach, those affected have to throw up. Roundworms in the colon are excreted in the stool.
Roundworms in the bile ducts and other organs
If roundworms get into the bile ducts, they can trigger what is known as biliary ascariasis. They clog the bile ducts and prevent bile from draining from the liver. The result is inflammation of the bile ducts (cholangitis) or encapsulated foci of inflammation (abscesses) in the liver. Severe pain attacks in the upper right abdomen attack those affected out of nowhere. They often vomit with bile and develop a fever.
If the bile does not drain for a long time, the skin and the whites of the eyes can turn yellowish (jaundice). Inflammation of the liver (hepatitis) can also develop. If roundworms infect the pancreas, symptoms of pancreatitis appear.
In rarer cases, roundworms can also invade the paranasal sinuses, the middle ear, the eyes or the female genitals and cause a wide variety of symptoms. They often peek out of the various body orifices or cause bumps.
Causes and risk factors of roundworms
Roundworms occur mainly in poor hygienic conditions. A high population density and moist soil favor their reproduction. Humans become infected by mouthing the eggs:
In adults, most eggs enter the body through contaminated food. If vegetables, fruit or other natural products are fertilized with faeces or waste water, roundworm eggs can stick to the food. Uncooked vegetables or raw lettuce are therefore common sources of infection for roundworms, just like contaminated drinking water. Children often get their eggs in their mouths while playing on the floor, in the dust, or with contaminated toys.
The eggs are very resilient and can survive for years in moist, warm soil. Only high temperatures above 40 degrees, direct sunlight and extreme drought can destroy the eggs. In areas with seasonal drought, people become infected only at certain times of the year.
Diagnosis of roundworms
If there is a suspicion of a roundworm infestation, one tries to detect the worms themselves, their eggs or their larvae in the body. If the worms have already colonized the intestines, their typical round-oval eggs can be identified from a stool sample under the microscope. A diagnosis of ascariasis can also be made if adult worms are completely excreted in the stool or vomited. In some cases, roundworms are discovered incidentally during a gastroscopy or colonoscopy. Roundworms can also be made visible in an ultrasound examination or X-ray examination with contrast medium.
In the first few days after an infection, however, it is more difficult to detect roundworms. Certain defense cells (eosinophils) can be found in increased numbers in the blood or in the saliva. However, these are not yet proof of a roundworm infection. Occasionally, larvae can be discovered in the saliva or gastric juice of those affected. If this proof is not successful, one must wait with the diagnosis until the roundworms have reached the gastrointestinal tract.
Treatment of roundworms
The anti-worm agents albendazole and mebendazole can kill roundworms in the body even after a single dose. Other active ingredients such as ivermectin and pyrantel are also effective against adult roundworms. However, the larvae are not killed by any of the drugs mentioned.
The active substances mentioned must not be used in pregnant women or only in urgently necessary cases.
Pronounced allergic reactions from roundworm infestation can be treated with cortisone preparations. An intestinal blockage caused by roundworms is always an emergency and must be treated surgically. If roundworms block the bile ducts, they are widened by medication. Simultaneous treatment with anti-worm medication usually leads to healing. Only rarely is it necessary to remove the worms with an endoscope or in a surgical operation.
Roundworms: course of the disease and prognosis
The course of the disease in worm diseases is determined by the life cycle of the worms. The parasites develop in different parts of the body and can cause a variety of symptoms. Individual worms are sometimes not noticed at all. If the worms reproduce quickly and live in large numbers in the body, the symptoms are usually more severe and complications are more frequent. Both an intestinal blockage and a lung infection can be fatal. Children are particularly at risk from these complications.
Although simple ascariasis can be cured with a single dose of medication, approximately 20,000 people die each year worldwide as a result of roundworms. Humans and worms will continue to co-exist as long as sanitation conditions do not improve in some places and human feces are used as fertilizer. Thoroughly cleaning and boiling potentially contaminated food, drinking water, or toys can keep roundworms away.
Roundworms are what type of biohazard?
They are causal agents of foodborne diseases and cause diseases such as trichinosis, filariasis, anisakiasis, hookworm, ascariasis, strongyloidiasis, toxocariasis, etc.
