infectious diseases can delay growth, particularly when coupled with: technologies introduced by western culture. too much protein consumption. poor nutrition. adequate vitamin d. humidity.

Parasitic infection because a parasitic disease, also known as parasitosis,  and aninfectious disease caused or transmitted by aparasite. Many parasites do not cause diseases.Parasitic diseases can affect practically all living organisms, including plants and mammals.
The study of parasitic diseases is called parasitology.

It is used to during sexual reproduction between humans