Highly contagious, especially in children. Children with congenital rubella are carriers and excrete virus. Problem is birth defects if virus is transmitted during the first trimester of pregnancy when fetal organ systems are developing. Measles - Rubeola. Serious illness characterized by high fever and rash.
Virus enters via nose, mouth or conjunctiva.
Koplik spots appear on the buccal mucosa 2-3 days before the rash and fever. Rash is caused by T cells killing virus in capillaries - but if this doesn't happen, virus becomes disseminated and causes encephalitis, or lung or kidney damage. Rubeola can be fatal. Fig 21.13 Recent epidemics of measles in college students may be because immunity isn't lifelong, or immunization took place too early. Evidently they once were protected by maternal Ab, but mothers who got vaccine rather than the illness don't have Ab that lasts as long.