Testicular immunology
Mumps is a viral disease which causes swelling of the salivary glands and testes. The mumps virus lives in the upper respiratory tract and spreads through direct contact with saliva. Prior to widespread vaccination programs, it was a common childhood disease. Mumps is generally not serious in children, but in adults, where sperm have matured in the testis, it can cause more severe complications, such as infertility.
Globalization and disease
Historically, measles was very prevalent throughout the world, as it is highly contagious. According to the National Immunization Program, 90% of people were infected with measles by age 15, acquiring immunity to further outbreaks. Until a vaccine was developed in 1963, measles was considered to be deadlier than smallpox. Vaccination reduced the number of reported occurrences by 98%. Major epidemics have predominantly occurred in unvaccinated populations, particularly among nonwhite Hispanic and African American children under 5 years old. In 2000 a group of experts determined that measles was no longer endemic in the United States. The majority of cases that occur are among immigrants from other countries.