Final answer:
Myxoviruses can cause various infectious diseases, but in the context of the given options, they are responsible for causing measles, a highly contagious infectious disease identified by a characteristic rash and other symptoms.
Step-by-step explanation:
The myxovirus family includes pathogens that cause notable infectious diseases such as the influenza viruses, the mumps virus, the measles virus, rabies virus, and others. When asked what disease the myxovirus causes, it's important to note that myxovirus is an older term that used to describe a group of viruses with certain common characteristics, such as being enveloped with a single-stranded RNA genome and the ability to cause infections in animals and humans.
In the case of the options provided, the myxovirus causes measles, which is an infectious disease characterized by symptoms including a high fever, conjunctivitis, a sore throat, and a distinctive rash that spreads over the body. Measles is caused by a single-stranded, negative-strand RNA virus that is highly contagious and spreads by direct contact with infectious secretions or by inhalation of airborne droplets.