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.
A long, narrow region of low land between ranges of mountains, hills, or other high areas, often having a river or stream running along the bottom. Valleys are most commonly formed through the erosion of land by rivers or glaciers. They also form where large regions of land are lowered because of geological faults.