By | June 10, 2022

Roundworms are among the most common human parasites. More than a fifth of the world’s population suffers from a roundworm infestation (medical: ascariasis ) and the infection is fatal in about one percent of those infected. Treating this parasitic disease can be very expensive, but prevention is relatively easy.

What are roundworms?

Roundworms belong to the roundworms and are very similar to earthworms in body shape and color. There are several species that specialize in different hosts. In addition to the actual human roundworm, humans can also be infected by dog, cat or pork roundworms. For comprehensive guide to urinary tract infection, please visit

The human roundworm is about 5 mm thick and up to 40 cm long. It does not require any intermediate host and, with the exception of the egg stage, spends its entire life cycle in the human body. When roundworm eggs enter the digestive tract with food, the larvae hatch in the small intestine and penetrate the intestinal wall. They first reach the liver via the blood vessels, where they reach another larval stage. They then move on to the heart and lungs.

After molting again, they are coughed up due to the phlegm and irritation they cause to cough. Some of them are swallowed again and thus get back into the gastrointestinal tract. Once they are back in the small intestine, they reach sexual maturity. This migration takes place on average in a period of 30 to 35 days.

The adult roundworms can reach an age of up to one and a half years. During this time, a female roundworm lays about 200,000 eggs every day, which are excreted with the faeces. Roundworms, for which humans are an accidental host, do not reach sexual maturity in the human intestine.


The most common way to get infected with roundworm eggs is through food that hasn’t been washed and cooked through enough. This is especially true for salads and vegetables that grow close to the ground, such as cucumbers or cabbage. Strawberries can also be contaminated with roundworm eggs. However, worm eggs can also be transmitted to other foods by flies.

Another route of transmission is gardening, as the soil can be contaminated with feces. The same applies to the sand on playgrounds. You can become infected with cat and dog roundworms when cleaning the litter box or removing dog excrement. Under certain circumstances, even the drinking water can be contaminated.

Symptoms, Ailments & Signs

In the course of their development, roundworms migrate through the human body. Therefore, not only complaints in the gastrointestinal tract occur, but also temporary symptoms affecting the respiratory tract. In the first period after infection with roundworm eggs, there are no symptoms.

If the larvae get into the lungs in the next stage, this leads to asthma-like attacks with coughing and shortness of breath, heavy mucus, painful breathing and bloody sputum. Rashes and facial swelling may also occur as an allergic reaction. These symptoms are temporary, lasting a week or two. However, life-threatening pneumonia can develop in children.

The young worms then reach the small intestine, where the adult roundworms prefer to live. A mild infestation is usually not noticeable through symptoms. However, mild abdominal pain, nausea, and vomiting may occur. In the case of a severe infestation, metabolic products from the parasites can cause allergic reactions and symptoms such as fever, severe abdominal pain, nausea, vomiting and diarrhea.

The worms can also impair the digestion of food. Symptoms of deficiency can be the result. If roundworms penetrate the intestinal wall, they can cause suppuration and abscesses. In rare cases, a heavy roundworm infestation leads to an intestinal obstruction, inflammation of the pancreas or gallbladder.

Diagnosis & History

In the initial phase or with only a small infestation with roundworms, the disease can initially go completely unnoticed. The first symptoms of an infection with roundworms are usually abdominal pain and a feeling of being unwell to a greater or lesser extent. Loss of appetite or ravenous hunger can also occur. A clear sign in this context can also be severe weight loss and an overall unhealthy appearance.

When the larvae reach the liver, colicky pain and the first allergic reactions can occur. These intensify when the roundworm larvae reach the lungs. There they can cause satarkic mucus, which is accompanied by coughing and fever. In the intestine, the adult worms can cause appendicitis and even an intestinal obstruction in severe infestations.

An infestation with roundworms is usually detected by examining the feces, in which the eggs are flushed out in the laboratory using a liquid solution. However, this diagnostic method is not suitable if the person is only infected with immature roundworms or roundworms that are specialized in other species. In these cases, a colonoscopy may be necessary.

Occasionally, roundworms also come out with the feces. A previously undetected roundworm infestation can become noticeable during anesthesia, as this interferes with the body’s metabolism. This can cause the worms to leave their host through the anus, but possibly also through the mouth and nose.


If left untreated, a massive infestation with roundworms can cause serious complications. Large amounts of roundworms in the intestine lead to severe diarrhea, vomiting and abdominal cramps. If the damaged intestinal mucosa can no longer absorb nutrients properly, children in particular will suffer from an undersupply, which is noticeable in weight loss and deficiency symptoms.

Clumped together, the worms can completely block the intestines (worm ileus). The situation is extremely critical when the inflamed intestinal mucosa tears and intestinal contents get into the abdominal cavity. In this case, immediate surgery is needed to avoid life-threatening peritonitis. If roundworms enter the bile ducts, they impede the flow of bile and can cause inflammation of the bile ducts or the liver.

A characteristic symptom of this is jaundice with severe yellowing of the skin and eyes. Rarely, an abscess forms in the liver, which, if left untreated, can lead to serious complications such as blood poisoning (sepsis). Roundworms can also cause massive inflammation in the pancreas, which requires immediate medical attention.

A severe roundworm infestation of the lungs is characterized by shortness of breath, fever, coughing and bloody sputum; if left untreated, pneumonia can develop. Allergic reactions such as facial swelling or skin rashes can also occur in rare cases as a complication of roundworm infestation.

When should you go to the doctor?

People who suffer from disorders of the gastrointestinal tract or pain in the stomach area should consult a doctor to clarify the symptoms. Fever, nausea and abdominal swelling indicate an irregularity in the organism that should be treated. In the case of exhaustion, reduced physical performance and inconsistencies in digestion, a doctor is required. If living beings can be seen in the faeces after going to the toilet, this should be checked by a doctor.

Changes in the appearance of the skin, coughing and restricted breathing are further signs of an existing disease. If there are changes in the shape of the face, anxiety or problems with the metabolism, a doctor is needed. If existing symptoms increase in scope and intensity, a diagnosis is advisable. A treatment plan is drawn up and medical care initiated. Without medical control, the germs can spread further in the organism.

Vomiting, diarrhea or diffuse deficiency symptoms occur. Inflammation can develop which contributes to a further deterioration in health. Bleeding from the bowel, abscesses, or a blockage in the bowel should be reported to a doctor immediately. With these symptoms, the disease is already advanced and the affected person needs therapy. Since roundworms can cause pneumonia in children, they should be examined by a doctor at the first sign.

Treatment & Therapy

An infestation with roundworms can be treated relatively easily with medication. In addition to some over-the-counter agents, various prescription-only active ingredients are available. These kill the worms in the intestines and ensure that they are excreted in the faeces.

However, the larvae remain unaffected by this, so that a repeat treatment may be necessary. The duration of treatment depends on how severe the disease is. In rare cases, physical interventions are necessary. These can be performed endoscopically as well as with classic surgical methods.


The most effective way to prevent roundworm infestation is hygiene. On the one hand, this means that fruit and vegetables are thoroughly cleaned before preparation. On the other hand, you should pay attention to consistent hand washing. This is of course particularly important after gardening, contact with a sandbox, going to the toilet and cleaning the litter box. However, it is also advisable to wash your hands thoroughly before preparing food, before meals and after contact with pets.


Drug treatment of ascariasis or mechanical removal of the worms as part of a colonoscopy only affects adult roundworms that are in the intestine. Worms that are still in the larval stages III and IV in organs such as the liver, lungs and larynx due to their specific development cycles are not killed.

They survive the treatment unscathed. After completion of the larval stage IV, they leave the larynx and reach the gastrointestinal tract by coughing up and swallowing. They only grow into adult roundworms in the small intestine and then infect the large intestine. It is therefore very likely that after successful treatment there will be another infestation and in most cases it cannot be attributed to a new infection.

For the above reasons, successful drug treatment of ascariasis should be repeated three weeks after the completion of treatment. Within the three-week waiting period until the next treatment, all undetected larvae have developed into adult worms and settled in the intestine. The renewed medication ensures that all “followers” are recorded and that freedom from worms is finally achieved. However, the measure does not protect against reinfection with roundworms, which have developed in the soil from eggs to larval stage II.

You can do that yourself

In everyday life, it is important to ensure that fresh foods such as fruit and vegetables are always cleaned before consumption. They are to be rinsed under running water. In addition, it is important that some foods are only consumed when they have been sufficiently cooked through. Especially foods that grow close to the ground should be boiled, roasted or baked before consumption. It is important to ensure that they cannot be ingested raw.

When preparing lettuce, make sure that it has been washed thoroughly. As soon as residues of soil or sand appear in a meal, the intake should be stopped. The storage of purchased food should also be checked on a daily basis and optimized if necessary. A transmission of pathogens by flies or other insects must be prevented. Fruit and vegetables in particular should therefore be covered or stored in a cool place.

People who have pets should take extra care when it comes to hygiene. The contact of the faeces of the animals must not occur with food to be consumed. The intake of fluids should also be checked in everyday life. The drinking water must be tested to avoid the transmission of diseases. When showering, washing and brushing your teeth, you have to pay attention to the quality of the water.