Roundworms are among the most common parasites in humans. More than one-fifth of the world’s population suffers from roundworm infestation (medical term: ascariasis), and in about one percent of those infected, the infection is fatal. Treatment of this parasitic disease can be costly, but prevention is relatively simple.
What are roundworms?
Roundworms belong to the nematode family 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 infested by dog, cat or pig roundworms. The human roundworm grows to 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, larvae hatch in the small intestine and penetrate the intestinal wall. Via the blood vessels, they first reach the liver, where they reach another larval stage. They then migrate to the heart and lungs. After shedding their skin again, they are coughed up due to the mucus and coughing stimulus they cause. Some of them are swallowed again and return to the gastrointestinal tract. Once they are back in the small intestine, they reach sexual maturity. This migration takes place over an average period of 30 to 35 days. Adult roundworms can reach an age of up to one and a half years. During this time, a roundworm female lays about 200000 eggs every day, which are excreted in the feces. Roundworms, for which humans are a false host, do not reach sexual maturity in the human intestine.
Causes
People usually become infected with roundworm eggs from food that has not been adequately washed or cooked through. This is especially true of 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 soil may be contaminated with feces. The same applies to the sand on playgrounds. When cleaning the cat’s litter box or removing dog feces, one can become infected with cat and dog powderworms. In some circumstances, even drinking water may be contaminated.
Symptoms, complaints and signs
In the course of their development roundworms travel through the human body. Therefore, not only complaints in the gastrointestinal tract occur, but also temporarily symptoms affecting the respiratory tract. In the first period after infection with roundworm eggs, there are not yet any symptoms. If the larvae reach the lungs in the next stage, this leads to asthma-like attacks with coughing and shortness of breath, severe mucus production, pain when breathing and bloody sputum. Skin rashes and facial swelling may also occur as an allergic reaction. These symptoms persist only temporarily for one to two weeks. In children, however, life-threatening pneumonia can develop. The young worms then enter the small intestine, where the adult roundworms prefer to live. A mild infestation is usually not noticeable by symptoms. However, mild abdominal pain, nausea and vomiting may occur. In severe infestations, metabolic products of the parasites can cause allergic reactions and symptoms such as fever, severe abdominal pain, nausea, vomiting and diarrhea. The worms can also impair food utilization. Deficiency symptoms can be the result. If roundworms penetrate the intestinal wall, they can cause suppuration and abscesses. In rare cases, a severe roundworm infestation leads to intestinal obstruction, inflammation in the pancreas or gallbladder.
Diagnosis and course
In the early stages or when there is only a small infestation of roundworms, the disease may initially go completely unnoticed. The first symptoms of an infection with roundworms are usually abdominal pain and more or less severe malaise. This may be accompanied by loss of appetite or ravenous appetite. A clear sign in this context can also be severe weight loss and an overall unhealthy appearance. When the larvae reach the liver, colic-like pain and initial allergic reactions may occur.These become more severe when the roundworm larvae reach the lungs. There they can cause severe mucus production accompanied by coughing and fever. In the intestine, the adult worms can cause appendicitis and even intestinal obstruction in severe infestations. Infestation with roundworms is usually detected with a fecal test, 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 infected only with immature roundworms or those that specialize in other species. In these cases, colonoscopy may be necessary. Occasionally, roundworms also come out with the feces. A previously undetected roundworm infestation may become apparent during anesthesia because it interferes with the body’s metabolism. This can cause the worms to leave their host through the anus, but also through the mouth and nose in some circumstances.
Complications
If left untreated, a massive infestation of roundworms can cause serious complications. Large numbers of roundworms in the intestines cause severe diarrhea, vomiting, and abdominal cramps. If the damaged intestinal mucosa can no longer absorb nutrients properly, this leads to an undersupply, especially in children, which becomes apparent in weight loss and deficiency symptoms. When clustered together, the worms can completely block the intestine (vermileus). The situation is extremely critical if the inflamed intestinal mucosa ruptures and intestinal contents enter the abdominal cavity. In this case, immediate surgery is necessary to prevent life-threatening peritonitis. If roundworms penetrate the bile ducts, they obstruct the outflow 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, abscess formation occurs in the liver, which without treatment can result in serious complications such as blood poisoning (sepsis). In the pancreas, roundworms can also cause massive inflammation that requires immediate medical attention. A severe roundworm infestation of the lungs is characterized by shortness of breath, fever, cough and bloody sputum; without treatment, pneumonia may develop. Allergic reactions such as facial swelling or skin rashes may also occur in rare cases as a complication of roundworm infestation.
When should you see a doctor?
People suffering from gastrointestinal disorders or pain in the stomach area should see a doctor to clarify the symptoms. Fever, nausea as well as swelling in the abdomen indicate an irregularity of the organism that should be treated. In case of fatigue of a decreased physical performance as well as inconsistencies of digestion, a doctor is needed. If after going to the toilet living beings can be perceived in the feces, this should be checked in a medical examination. Changes of the skin appearance, cough as well as restrictions of the respiratory activity are further signs of a present illness. If changes in the shape of the face, anxiety or problems with the metabolism occur, a doctor is needed. If already existing complaints increase in scope and intensity, a diagnosis is advisable. A treatment plan is created and medical care is initiated. Without medical control, germs can continue to spread in the organism. Vomiting, diarrhea or diffuse deficiency symptoms occur. Inflammations can develop which contribute to further deterioration of health. Bleeding of the intestine, abscesses or intestinal obstruction should be presented to a physician 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 seen by a doctor at the first signs.
Treatment and therapy
Infestation with roundworms can be treated relatively easily with medication. In addition to some over-the-counter remedies, various prescription agents are available for this purpose. These kill the worms in the intestine and ensure that they are excreted in the feces. The larvae, however, remain unaffected, 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 both endoscopically and with classical surgical methods.
Prevention
The most effective means of preventing an infestation of roundworms is hygiene. This includes, first, thoroughly cleaning fruits and vegetables before preparing them. On the other hand, care should be taken to wash hands consistently. This is of course particularly important after gardening, contact with a sandbox, going to the toilet and cleaning the cat’s litter tray. However, it is also advisable to wash hands thoroughly before preparing food, before meals and after contact with pets.
Aftercare
Drug treatment of ascariasis or mechanical removal of worms during colonoscopy act only on adult roundworms that are present in the intestine. Worms that are still in 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 unharmed. After completion of larval stage IV, they leave the larynx and enter the gastrointestinal tract by coughing up and swallowing. Only in the small intestine do they grow into adult roundworms and subsequently infest the large intestine. It is therefore very likely that a new infestation will occur after successful treatment, and in most cases this cannot be attributed to a new infection. For the above reasons, successful drug treatment of ascariasis should be repeated three weeks after completion of treatment. Within the three-week waiting period before re-treatment, any unrecaptured larvae will have developed into adult worms and settled in the intestine. The renewed medication ensures that all “stragglers” are captured and worm freedom is finally achieved. However, the measure does not protect against reinfection with roundworms that have developed in the soil from egg to larval stage II.
What you can do yourself
In everyday life, make sure that fresh foods such as fruits and vegetables are always cleaned before consumption. They should be rinsed under running water. In addition, it is important that some foods are ingested only when they have been sufficiently cooked through. In particular, foods that have a growth close to the ground should be boiled, fried or baked before consumption. Care should be taken to ensure that they cannot be ingested raw under any circumstances. When preparing lettuce, make sure it has been thoroughly washed. As soon as residues of soil or sand appear in a meal, stop ingesting it. The storage of purchased food should also be checked on a daily basis and optimized if necessary. Transmission of pathogens by flies or other insects must be prevented. Therefore, fruit and vegetable items in particular should be kept covered or refrigerated. People who have pets should take special care with hygiene. Under no circumstances should the animals’ feces come into contact with food to be consumed. The supply of liquids should also be checked in everyday life. Drinking water should be checked to prevent the transmission of diseases. When showering, washing and brushing teeth, pay attention to the quality of the water.
