麻疹, also known as measles, is a highly contagious viral infection that primarily affects children. It is caused by the measles virus and spreads through respiratory droplets when an infected person coughs or sneezes. Symptoms typically include high fever, cough, runny nose, and a distinctive red rash that usually appears a few days after the initial symptoms. Vaccination is the most effective way to prevent 麻疹. The measles, mumps, and rubella (MMR) vaccine is commonly administered to children, providing immunity against these diseases. Despite the availability of vaccines, outbreaks can still occur, especially in communities with low vaccination rates.