Simplify the following text for a Grade 13 native English-speaking person.
Original: In 1948 he received the Nobel Prize in Physiology or Medicine for his 1939 discovery of insecticidal qualities and use of DDT in the control of vector diseases such as malaria and yellow fever .
Simplified: He won the Nobel Prize in Physiology or Medicine in 1948 for his discoveries discovery of insecticidal qualities and use of DDT in the control of vector diseases .