Definitive host of ascariasis
High-Yield Explanation
Ref: Harrisons, 19th ed. pg. 1413* Ascaris lumbricoidesis the largest intestinal nematode parasite of humans, reaching up to 40cm in length.* Humans are definitive host of ascaris* Clinical disease arises from larval migration in the lungs or effects of the adult worms in the intestines.* Clinical Features:# Around, 9-12 days after egg ingestion, patients may develop an irritating non-productive cough and burning substernal discomfort that is aggravated by coughing or deep inspiration.# Eosinophilia develops during this symptomatic phase and subsides slowly over weeks.# Chest x-rays may reveal evidence of eosinophilic pneumonitis (Loffler's syndrome), with rounded infiltrates a few millimeters to several centimeters in size.* Treatment: Mebendazole (DOC)