Who has ever heard of paramyxoviruses?  Chances are not very good unless you've taken a virology class.  Well, you actually know more about the family paramyxoviridae than you imagined.  For instance, four common paramyxoviruses are measles, mumps, parainfluenza, and respiratory syncytial viruses.  Unless they've been vaccinated, most people had all of these viruses when they were children.  Measles and mumps are no longer common diseases in the United States because of widespread immunization, but are still important childhood diseases in developing countries.  Measles alone kills nearly two million children in third world countries each year.  If you've never had measles, consider yourself lucky because the virus can lead to sever neurological complications which may manifest up to ten years after you've had it.
    Parainfluenza viruses and RSV are some of the main causes of pneumonia and other lower respiratory tract infections in young children.  Many infants become severely ill and are hospitalized because of these infections.  Vaccines are currently being tested and hopefully they will be licensed for general use soon.
For further information on general and clinical aspects of paramyxoviruses please see the Humans and Viruses class page from 1998.   Paramyxo