Ascariasis : Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present. Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition and learning problems. Symptoms may include shortness of breath and fever in the beginning of the disease. These may be followed by symptoms like abdominal swelling, abdominal pain and diarrhea.
Infection occurs by eating food or drink contaminated with Ascaris eggs from feces. The eggs hatch in the intestines, burrow through the gut wall, and migrate to the lungs via the blood. There they break into the alveoli and pass up the trachea, where they are coughed up and swallowed. The larvae then pass through the stomach for a second time into the intestine where they become adult worms.