Complex sentence: Up to 2000 of these nematodes can be found in a single human, resulting in around 100,000 deaths a year most of which are in South America, S.E. Asia and Africa.
Split into simpler sentences: Up to 2000 of these nematodes can be found in a single human. Macroparasitic infection results in around 100,000 deaths a year, most of which are in South America, Southest Asia, and Africa.