Measles, also known as “Rubeola,” is a leading cause of death of young children worldwide, despite the availability of an inexpensive and effective vaccine. Measles-related deaths most frequently occur in developing countries with poor health care systems. Prior to introduction of the measles vaccine in 1963, infection during childhood was nearly 100%, causing the measles virus to be named “the most infectious of microbial agents."
Microbe name: Morbillivirus of the Paramyxoviridae family
Type of microbe: RNA Virus
How it causes disease: The measles virus grows in cells that line the back of the throat and lungs. It is spread through the lymphatic system (a system that controls circulating immune cells) throughout the body, causing a systemic viral infection, called “viremia.” A person’s antibodies attack the virus, which coincidentally also damages the walls of tiny blood vessels, leading to a rash.
How it spreads: Measles is a highly contagious infection spread through coughing and sneezing. The infection is contagious 4 days before and 4 days after appearance of the measles rash. The virus can live and remain infectious for up to 2 hours on contaminated surfaces, so hand hygiene is very important in prevention. It has been estimated that, in the absence of vaccination or prior infection, all people will get measles at some point in their lives.
Who’s at risk? Anyone who has not been vaccinated.
Symptoms: Symptoms typically first appear about 10 to 12 days after virus exposure. A high fever that lasts 4 to 7 days is accompanied by a runny nose, cough, red, watery eyes, and small white spots inside the cheeks. Between 7 to 18 days after exposure, a rash will appear on the face and neck, spreading downward over a period of 3 days and lasting 5 to 6 days.
Diagnosis: Diagnosis of measles is most commonly performed by sampling blood for antibodies against the measles virus. Less common methods include detection of the virus or viral DNA, but these techniques have been less reliable and are not routinely used for diagnostic purposes.
Prognosis: The prognosis for measles in healthy children is usually good. However, in developing countries, measles is associated with complications, especially in small children under 5 years who are malnourished and in adults over 20 years. These complications are more common among malnourished individuals and can include blindness, brain infections, and death. See "complications" below.
Treatment: There are no antiviral medications for treating measles. Treatment includes supportive care, such as good nutrition and lots of fluids to prevent dehydration. Treatment with vitamin A supplements have been shown to reduce measles-related death and blindness and are recommended for malnourished children in developing countries.
Prevention: A live, attenuated measles vaccine became available in 1963 and is combined with vaccines for mumps and rubella (MMR vaccine). When given at 12 to 15 months, the vaccine provides over 90% protection. A second booster dose is recommended prior to entry into kindergarten.
Complications: Complications of measles are relatively common and include ear infections (~10% infected children), pneumonia (~5%), and brain infections leading to deafness or mental retardation (0.1%). Risk for death is ~0.1% to 0.2% worldwide, but up to 25% in developing countries, where malnutrition is a problem. In Africa, measles is the leading cause of blindness in children.
Sources:
Cohen J and Powderly WG. Infectious Diseases, 2nd ed. ©2004 Mosby, An Imprint of Elsevier.
Measles. WHO. Accessed: February 19, 2009. http://www.who.int/mediacentre/factsheets/fs286/en/index.html.
