An 18-month-old boy, who is visiting family in San Antonio with his parents from Central America, presents with a 3-day history of fever, malaise, conjunctivitis, coryza, and cough. He had been exposed to a child with similar symptoms approximately 2 weeks prior. A day before, he developed a maculopapular rash that blanches under pressure (Figures 111-1 and 111-2). His shot records are unavailable but his mother states that his last vaccine was before age 1 year. He is diagnosed with measles and supportive care is provided.
Typical measles rash that began on the face and became confluent. (Used with permission from the University of Texas Health Sciences Center, Division of Dermatology.)
The typical measles rash on the trunk. (Used with permission from the University of Texas Health Sciences Center, Division of Dermatology.)
Measles is a highly communicable, acute viral illness that is still one the most serious infectious diseases in human history. Until the introduction of the measles vaccination, it was responsible for millions of deaths worldwide annually. Although the epidemiology of this disease makes eradication a possibility, the ease of transmission and the low percentage of non immunized population that is required for disease survival have made eradication of measles extremely difficult.
Last major outbreak in the US was during 1989 to 1990 and prompted a change in immunization policy in 1991, so that all children are to have two measles-mumps-rubella (MMR) vaccines before starting kindergarten.
This practice interrupted the transmission of indigenous measles in the US by 1993 and reduced incidence of measles to an historic low (<0.5 cases per million persons) by 1997 to 1999.1
After an all-time low of 34 cases were reported in 2004 in the US, the annual incidence began to increase with most cases linked to international travel of inadequately vaccinated Americans to endemic areas. Incomplete vaccination rates facilitate the spread once the virus is imported to the US causing clusters of periodic outbreaks.1
The worldwide incidence of death from measles was effectively reduced from an estimated 733,000 deaths in 2000 to an estimated 164,000 deaths in 2008 with mass vaccination campaigns by the member countries of the World Health Assembly.2 In 2008, about 83 percent of the world’s children received one dose of measles vaccine by their first birthday through routine health services—up from 72 percent in 2000.3
Measles elimination is now considered a feasible target. The World Health Organization have renewed their commitment to eliminate measles transmission by 2015. This will require greater than 95 percent of the population receives two doses of the MMR vaccine.4
Etiology and Pathophysiology