Children are most commonly infected. Estimated prevalence rates among children in various world regions are 4â28%. Ascariasis: Ascaris, or roundworm, infection is the common helminthic infection in humans, with an estimated worldwide prevalence of 1 billion. The causative organism, A lumbricoides, is cosmopolitan in distribution, being most abundant in tropical countries.
Definition of hollow. 1  1 : an unfilled space : cavity, hole in the hollow of a tree. 2  2 : a depressed or low part of a surface; especially : a small valley or basin.
baÂ·sin (bÄâ²sÄ­n) 1. An enclosed area filled with water. 2. A region drained by a river and the streams that flow into it. 3. A low-lying area on the Earth's surface in which thick layers of sediment have accumulated. Some basins are bowl-shaped, and others are shaped like long valleys that have been filled in.