Disease caused by the parasitic roundworm Ascaris lumbricoides
This article is about the infection. For the organism, see Ascaris.
Not to be confused with acariasis, a mite infection, principally of skin.
Medical condition
Ascariasis
High number of ascaris worms – visible as black tangled mass – are filling the duodenum, the first portion of the bowel after the stomach, of this South African patient (X-ray image with barium as contrast medium).
Ascariasis is a disease caused by the parasitic roundwormAscaris lumbricoides.[1] Infections have no symptoms in more than 85% of cases, especially if the number of worms is small.[1] Symptoms increase with the number of worms present and may include shortness of breath and fever in the beginning of the disease.[1] These may be followed by symptoms of abdominal swelling, abdominal pain, and diarrhea.[1] Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition, and learning problems.[1][2][5]
Infection occurs by ingestion of food or drink contaminated with Ascaris eggs from feces.[2] The eggs hatch in the intestines, the larvae burrow through the gut wall, and migrate to the lungs via the blood.[2] There they break into the alveoli and pass up the trachea, where they are coughed up and may be swallowed.[2] The larvae then pass through the stomach for a second time into the intestine, where they become adult worms.[2] It is a type of soil-transmitted helminthiasis and part of a group of diseases called helminthiases.[6]
^Fung IC, Cairncross S (March 2009). "Ascariasis and handwashing". Transactions of the Royal Society of Tropical Medicine and Hygiene. 103 (3): 215–22. doi:10.1016/j.trstmh.2008.08.003. PMID18789465.