Ascariasis: An Extremely Common Parasitic Infection

Imagine a disease that affects a large percentage of the world's population. It does exist. Perhaps you are thinking of HIV/AIDS or cancer. It is neither of these. It is a disease called ascariasis. Ascariasis affects a huge number of people worldwide. In fact, it is estimated that as many as one-quarter of the world's population is affected by the disease. However, not many people are even aware of the disease. So what exactly is ascariasis?

Ascariasis is an intestinal infection caused by the parasitic roundworm Ascaris lumbricoides. Ascaris lumbricoides causes infections in humans after direct or indirect contact with contaminated soil or through ingestion. Infections occur once the fertilized eggs hatch in their host. The larvae then burrow through the intestine, travel to the liver, and finally to the respiratory system. They are eventually reswallowed and mature in the intestine. They can grow to be quite large, sometimes more than a foot in length. In fact, Ascaris lumbricoides is the largest roundworm that affects humans. The worms can live for nearly two years. The female worms produce more than 200,000 eggs per day. Once the fertilized eggs are shed, the cycle starts all over again. In the United States, approximately two percent of the population is affected by ascariasis. The disease is much more common in other parts of the world. In particular, the disease frequently affects individuals in tropical and developing countries as well as areas with poor sanitation and overcrowding. Children are particularly susceptible to the disease. More than a billion people are affected by ascariasis worldwide.

Symptoms vary greatly from patient to patient. It depends on the severity of the infection and the number of worms present. Symptoms also vary during the parasite's life cycle. In most cases, there are no symptoms present. It also isn't uncommon for patients to remain asymptomatic for long periods of time. When symptoms do occur, they can include worms in stool, coughing up worms, worms exiting through the nose or mouth, loss of appetite, fever, cough, bloody sputum, wheezing, inflammation, enlargement of the liver and/or spleen, toxicity, pneumonia, nutritional deficiency, obstruction of the bowel, obstruction of the bile and/or pancreatic duct, vomiting, shortness of breath, severe stomach and/or abdominal pain, swelling of the abdomen, and skin rash. Children are particularly susceptible to severe complications from ascariasis. This is because their intestines are smaller and the nutritional intake is smaller than that of adults.

Diagnosis usually occurs after a worm is passed in the stool. In other cases, ascariasis is usually suspect when abdominal pain and malnutrition are present. A physical examination, review of the symptoms, and review of medical history are necessary in the diagnosis. Stool samples and other tests looking for the parasite aid in diagnosis. X-rays and blood tests may also aid in the diagnosis of ascariasis. Treatment is aimed at killing the worms by the use of antiparasitic medications. Treatment may vary from patient to patient depending on the severity of the condition. It is usually necessary to perform follow-up tests a few weeks after treatment to make sure the worms have been eradicated from the body. It is also advisable that patients be checked for other parasitic infections. Prognosis is extremely good with treatment. Even without treatment, the condition can resolve on its own.

Ascariasis is an intestinal infection caused by the parasitic roundworm Ascaris lumbricoides. The disease affects more than a billion people worldwide. Despite its prevalence, not many people are even aware of the disease. Symptoms vary greatly from patient to patient. Children are particularly susceptible to ascariasis and its severe complications. Treatment is aimed at killing the worms. Prognosis is extremely good with or without treatment.