Diagnosis of the Measles Virus

Measles is diagnosed by the presence of certain characteristic symptoms and confirmed by specific lab tests. A blood sample is tested for the presence of special measles-specific antibodies (IgM) and RNA strands exclusive to the measles virus. A throat swab and urine test can also be done to detect the presence of a measles infection. The first step in diagnosis, however, is the analysis of symptoms. Measles follows a characteristic pattern:

1. Incubation Period (6-19 days): the infected individual is likely asymptomatic (no symptoms) during this time period. Some people may experience very temporary respiratory symptoms or fever. Inside the body the virus is multiplying and moving from the respiratory tract (where it enters the body, locally) to the lymphatic system (how it spreads all over the body, systemically). Because the infected individual may have no symptoms, it can be very dangerous in terms of spreading to other people. A person is usually the most contagious five days before the appearance of rash (prodrome period) to four days afterward.

2.  Prodrome Period (2-8 days): infected individuals will have a fever (up to 40 degrees Celsius), just feel icky (technical term “malaise”), have a loss of appetite, red eyes and a cough. Koplik’s spots may appear on mucosa (mainly in the mouth) and they looks like tiny grains of salt.

3. Exanthem Period (6-7 days): the characteristic rash appears in this phase. It typically starts on the face and spreads from the core of the body outwards and from the head downwards. See pictures for what this rash looks like!

The important take away here is that measles is very contagious, especially during the incubation period when you might not even know if you have it. If there is any chance you’ve been exposed, contact your doctor/nurse to get further testing to diagnose the virus and stay away from anyone who has not been vaccinated! Also, to prevent all this trouble in the first place, GET VACCINATED!!!! Just a subtle plug for immunizations…

 Reference/More resources: 

Barinaga, J.L., Skolnik, P. (2015). Clinical Manifestations and Diagnosis of Measles. Retrieved from http://www-uptodate-com.offcampus.lib.washington.edu/contents/clinical-manifestations-and-diagnosis-of-measles?source=machineLearning&search=measles+diagnosis&selectedTitle=1~150&sectionRank=1&anchor=H25#H25

Measles (Rubeola) (2015). CDC. Retrieved from http://www.cdc.gov/measles/hcp/index.html