Bacteriology at UW-Madison
The Microbial World
Lectures in Microbiology by Kenneth Todar PhD University of Wisconsin-Madison Department of Bacteriology
© 2009 Kenneth Todar PhD
Measles (rubeola) is one of the most
infectious diseases known. Prior
to widespread immunization, measles was a common childhood disease,
with greater than 90% of infants and children infected by 12 years of
vaccine usage was begun in 1963, efforts to eliminate measles in the
States have resulted in record low numbers of reported cases.
Since 1997, measles has not been endemic in the United States. The
measles virus does not circulate in the United States except in limited
outbreaks following importation from other countries. The risk of
measles in the United States is low because of the high population
immunity achieved through vaccination. However, the risk of exposure to
measles outside the United States can be high.
Measles remains a common disease in many developing countries and in
some developed countries in Europe and Asia.
Measles virus is an enveloped ss (-)RNA virus, a member of the
paramyxovirus family, which also includes mumps virus, respiratory
syncycial virus (RSV) and the canine distemper virus (CDV) of dogs and
cats. Its natural host is humans and monkeys.
Pathogenesis of Measles
The pathogenesis of measles resembles the general pattern for smallpox.
The disease presents with cough, runny nose, fever, red eyes and white
spots (Koplick spots) inside
the mouth. This is followed 3 to 7 days
later by a red blotchy skin rash, which spreads from the face
the rest of the body. The rash usually lasts 4 - 7 days but can
persist for up to 3 weeks. Measles is
frequently complicated by middle ear infection or diarrhea. The disease
can be severe, with bronchopneumonia or brain inflammation
(encephalitis) leading to death in approximately 2 of every 1,000 cases
in developed countries. In the developing world, case-fatality rates
often exceed 150 deaths per 1000 cases.
characteristic red, blotchy rash appears around the third day of
illness, beginning on the face and becoming generalized. The skin
rash of measles is an allergic response to virus products in the body
rather than direct viral multiplication in skin cells. www.info.gov.hk/dh/diseases/CD/Measles.htm
spots are a characteristic of measles used in diagnosis. They
appear opposite the molars as red spots with blue white centers. www.info.gov.hk/dh/diseases/CD/Measles.htm
Measles is spread by respiratory droplets or by direct contact with
nasal or throat secretions of infected persons, and less commonly, by
articles contaminated with nose and throat secretions. Measles is one
most highly communicable infectious diseases known. The patient can
disease to other persons from beginning of the disease to 4 days after
appearance of the rash. The incubation period before the disease varies
from 7 to 18 days, usually around 14 days.
There is no specific antiviral therapy for measles, and the basic
treatment consists of providing necessary supportive therapy such as
hydration and antipyretics and treating complications such as
pneumonia. Multiple studies have shown that vitamin A supplementation
improves outcome of measles in communities where vitamin A deficiency
is known to occur. Although vitamin A deficiency is not a major problem
in the United States, low serum concentrations have been found in
children with severe measles. Therefore, the American Academy of
Pediatrics recommends vitamin A supplementation be considered for
months of age and older.
Measles vaccine contains live, attenuated measles virus. It is
available as a single-antigen preparation or combined with live,
attenuated mumps or rubella vaccines, or both. Combined measles, mumps,
and rubella (MMR) vaccine is recommended whenever one or more of the
individual components are indicated.
The recommended routine age for measles vaccination of infants in
United States is 12-15 months. A single dose of MMR vaccine induces
antibody formation to all three viruses in at least 95% of susceptible
persons vaccinated at 12
months of age or older. A second dose is expected to induce immunity in
vaccines who do not respond to the first dose. The second dose should
be separated from the first by at least 28 days and is routinely
administered at 4-6 years of age.
Immunity to measles is considered permanent. Most
persons born before 1957 have had measles disease and are generally not
considered to be susceptible. However, measles or MMR vaccine may be
given to these persons if there is reason to believe they might be
National Immunization Program: Measles
Yellow Book: Measles (Rubeola)
Written and Edited by Kenneth Todar. All rights
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