Final answer:
Measles is associated with Koplik's spots and the recommended vitamin treatment is Vitamin A supplementation to help reduce the disease's severity and prevent complications.
Step-by-step explanation:
The disease that is associated with Koplik's spots and vitamin treatment is measles, and the vitamin supplementation recommended is Vitamin A. Koplik's spots are small, white, grain-like spots found on the inside of the mouth and are considered a characteristic sign of measles. Measles is a highly contagious viral disease that begins with symptoms such as high fever, conjunctivitis, sore throat, and a macular rash that becomes confluent. In severe cases, measles can lead to fatal complications such as pneumonia or encephalitis. The World Health Organization recommends Vitamin A supplementation in children with measles to help prevent eye damage and blindness, reduce the severity of the disease and prevent measles-related deaths.