Measles virus
is a paramyxovirus and the two membrane envelope protein allows it to be
pathogenic. The virus is easily inactivated by heat, sunlight, acidic pH,
either, and trypsin. It even has a short survival time outside the host on objects,
surfaces, and the air (P). Measles is among the most contagious viral diseases
known. Measles is transmitted from person to person through respiratory droplets.
Infected people are usually contagious 4 days before the rash appears and 4
days after (2).
The
incubation period is 7-21 days from exposure to onset of fever. A rash usually
appears about 14 days after exposure. Symptoms include a high fever,
conjunctivitis, runny nose, cough, Koplik spots (or white spots fount in the
buccal mucosa). The rash is characterized by red blotchy (maculopapular) rash
on the third to seventh day after onset
of symptoms. The rash will begin at the face, becomes generalized, and lasts
4-7 days. Some common complications
include diarrhea, middle ear infection, and pneumonia. Encephalitis, which can
result in permanent brain damage, occurs in approximately 1 per 1,000–2,000
cases of measles. The risk of serious complications and death is highest for
children aged under 5 years and adults aged over 20 years. Measles can cause Subacute
sclerosing panencephalitis (SSPE) is a progressive neurologic disorder (2).
(3).
Multiple
versions of the measles vaccine were created. However, the current MMR vaccine available
is a live attenuated vaccine as MMR or MMRV (ProQuad) which has varicella in
addition to measles, mumps, and rubella. The vaccine has been shown to have 95%
in 12 months of age and 98% in 15 months of age. The vaccine provides immunity
for life. The CDC recommends at least one dose for children 12 months or older and
then a second dose at age 4-6 years old. Single antigen measles vaccine is not available
in the US (1).
Humans are the only known hosts which is
why it is targeted for eradication. The number of reported measles cases in the
US has declined from almost 500,000 annually before to 37-667 cases from 2001 –
2017. This is the result of high vaccination rates and it was declared eliminated in 2000. However,
because measles is still prevalent worldwide there are still cases in the
united stated affecting those who are not vaccinated. Globally in 2016 the annual reported
measles incidence was 19 cases per million populations (2).
Resources:
Centers for
Disease Control and Prevention. (2019, April 15). Pinkbook. Retrieved May 08,
2020, from https://www.cdc.gov/vaccines/pubs/pinkbook/meas.html
Centers for Disease Control and Prevention. (2019, June 24). Measles (Rubeola) - Chapter 4 - 2020 Yellow Book. Retrieved May 07, 2020, from https://wwwnc.cdc.gov/travel/yellowbook/2020/travel-related-infectious-diseases/measles-rubeola
