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What is Measles (Rubeola)?
Measles (Rubeola) is a respiratory disease caused by a paramyxovirus, genus Morbillivirus with a core of single-stranded RNA. Measles is highly contagious and causes a systemic infection that begins in the nasopharynx (upper area of the throat behind the nose). The virus is highly contagious but it can easily be destroyed by light, high temperatures, UV radiation or disinfectants. Measles viruses are divided into eight clades (A to H) and while 24 genotypes have been confirmed, only 19 have been detected since 1990.
Measles causes a systemic infection that begins in the nasopharynx. The virus is transmitted through respiratory secretions (nasal discharge, coughing sneezing) and an infected person is contagious for four days prior to the onset of symptoms up until three to four days after rash onset.
Measles is unique to humans. Before the first measles vaccine was licensed for use in the U.S. in 1963, measles cases and outbreaks were seen generally in late winter and spring usually every two to three years.
Measles symptoms begin 10-14 days after close contact with someone infected with measles. Symptoms start with a fever, cough, runny nose, conjunctivitis, and white spots in the mouth, and progresses to a rash that starts on the face, spreads to the rest of the body, and lasts for about a week. Prior to the appearance of the measles rash (on the fourth or fifth day after fever begins), measles can be mistaken for several illness including influenza, bronchiolitis, croup, or pneumonia.
Other symptoms of measles include:
- Light sensitivity
- Watery eyes
- Body aches
- Swollen eyelids
Illnesses that may also develop along with measles are ear infections, diarrhea, croup, bronchiolitis and pneumonia.
Complications include very high fever, diarrhea, otitis media, seizures, pneumonia, encephalitis (0.1% reported), and very rarely, subacute sclerosing panencephalitis (SSPE - a progressive, debilitating and deadly brain disorder), and death. Measles during pregnancy may result in a premature birth or a low birth-weight infant. Recovery from measles will create antibodies that confer long-lasting immunity.
In the past, when measles infections were common, doctors diagnosed measles from the presence of tiny white specks surrounded by a red halo inside the cheeks of an infected person’s mouth. However, as measles is no longer common, the measles rash has been frequently misdiagnosed by physicians as scarlet fever, Kawasaki Disease, and dengue. The Centers for Disease Control (CDC) urges healthcare providers to consider measles when a patient presents with a febrile rash, and to notify the local health department of any suspected cases within 24 hours.
Confirmation of measles must be made by laboratory diagnosis (blood, throat swab) as physician reports of measles cases based on symptoms are no longer accepted by the CDC as confirmation of the disease. Additionally, measles genotyping should be completed as this is the only way to determine whether a person has wild-type measles or a rash as a result of a recent measles vaccination (vaccine-strain measles).
“Modified” measles can also occur in persons with some degree of immunity, as well as in previously vaccinated persons, who get a milder form of measles. “Atypical” measles can occur in a person, who was previously vaccinated with a killed-virus vaccine used from 1963 to 1967, and who is exposed to wild-type measles. The course of atypical measles is generally longer than natural measles.
IMPORTANT NOTE: NVIC encourages you to become fully informed about Measles and the Measles vaccine by reading all sections in the Table of Contents , which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.