The first of a series of health-related educational shorts produced by the Disney studios and the Coordinator of Inter-American Affairs for showing in Latin America. It was also the only one to use established Disney characters (the Seven Dwarves).
In this propaganda short, the viewers are taught about how the mosquito can spread malaria. A young mosquito flies into a house and consumes the blood of an infected human. She then consumes the blood of a healthy human, transmitting the disease into him. It turns out that this is actually a film within a film and the Seven Dwarves are watching it. They volunteer to get rid of the mosquito by destroying her breeding grounds.