Infection with ascaris is caused by a parasitic roundworm called Ascaris lumbricoides, which usually affects the small intestine and sometimes the lungs. Around 10 percent of people in developing countries carry intestinal worms, including ascariasis, according to the World Health Organization. However, in developed countries with modern sanitation, ascariasis is rare.
Roundworm eggs found in soil or food that has been contaminated with human feces are the main cause of ascariasis. After hatching, larvae travel to the lungs through the bloodstream. In the intestine, they mature and move up to the throat, where they are swallowed again and returned to the intestine. In the intestine, they become adult worms that reach 40 cm in length. Adult worms mate and produce eggs, which are excreted in feces and can infect others.
Some of the ways that people can get ascariasis are:
Eating raw or undercooked vegetables or fruits that have been grown in or washed with contaminated soil.
Drinking water that has been contaminated by human or animal feces.
Putting hands or fingers in the mouth after touching contaminated soil or objects.
Having direct contact with an infected person’s feces.
Many people with ascariasis have no symptoms or only mild symptoms. However, some people may experience more severe symptoms depending on the number and location of the worms.
Some of the possible symptoms of ascariasis are:
Abdominal pain, cramps, bloating, or distension.
Nausea, vomiting, diarrhea, or constipation.
Loss of appetite or weight loss.
Malnutrition or growth impairment in children.
Worms in the stool or vomit.
Cough, wheeze, shortness of breath, chest pain, or blood in the mucus.
Fever, fatigue, or allergic reactions.
In rare cases, ascariasis can cause serious complications, such as:
Intestinal obstruction or perforation, which can lead to infection, bleeding, or shock.
Biliary or pancreatic obstruction, which can cause jaundice, inflammation, or infection of the liver or pancreas.
Lung damage or pneumonia, which can impair breathing and oxygen exchange.
Appendicitis, which can cause inflammation and infection of the appendix.
The diagnosis of ascariasis is usually based on the detection of eggs or worms in the stool or vomit of the infected person. Usually, a stool sample is examined under a microscope for the presence of eggs or larvae. A blood test may also be done to check for an increase in eosinophils, a white blood cell that is responsible for parasitic infection.
In some cases, imaging tests, such as chest X-rays, ultrasound, or CT scan, may be done to look for worms or complications in the lungs, liver, or pancreas.
The treatment of ascariasis is usually done with anti-parasitic medications, which kill the worms and help expel them from the body. Some of the common drugs used for ascariasis are:
Albendazole, which is taken as a single dose or for 1 to 3 days.
Mebendazole, which is taken for 3 days.
Pyrantel pamoate, which is taken as a single dose.
Ivermectin, which is taken as a single dose.
Although these drugs are generally safe and effective, they may cause nausea, vomiting, headaches, dizziness, or allergic reactions. Pregnant or breastfeeding women and children under 2 are not recommended to take them.
In some cases, surgery may be needed to remove the worms or treat the complications, such as intestinal obstruction, perforation, or appendicitis.
The prevention of ascariasis is mainly based on improving sanitation and hygiene, which can reduce the transmission and spread of the infection. Some of the preventive measures are:
Washing hands with soap and water before eating, after using the toilet, and after touching soil or animals.
Boiling, filtering, or treating water before drinking or cooking with it.
Washing, peeling, or cooking vegetables and fruits before eating them.
Avoiding contact with human or animal feces or soil that may be contaminated.
Disposing of human and animal feces properly and away from sources of water or food.
Using latrines or toilets that are clean and well-maintained.
Educating people about the risks and symptoms of ascariasis and the importance of seeking medical attention if infected.
