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.
The shape of the land. A valley is a relatively large hollow or depression bounded by hills or mountains on Earth's surface that is developed by stream erosion or glacial activity and that is drained externally. A basin is another hollow or depression on Earth's surface, but it has no outlet to drain the water.