Measles
Yesterday I wrote about the current measles outbreak in Ohio and promised a follow-up post all about measles. Here we go… settle in, grab a cup of tea (or wine!), and get ready for an action-packed read…
Measles is one of my favorite diseases because —
the measles virus hasn’t changed in ~5000 years (seriously, how amazing is that? Measles was around when the Egyptian pyramids were being built; the same virus. There is archeological evidence showing the measles virus in Sumeria in the Tigris & Euphrates river valley in 3000 BCE — amazing, right?!?!)
it is the most infectious disease known among humans (one case of measles leads to 12-18 additional cases; yes, that is an R-naught of 18).
we could eradicate it through vaccinations (without an animal reservoir and with an effective vaccine, the disease could be eliminated from the globe).
Measles is an acute (a sudden and you only get it once) respiratory virus. It is a single-stranded, enveloped RNA virus. Typically RNA viruses mutate/evolve/change a lot; however, the measles virus has NOT changed throughout history (seriously, the same virus existed in 3000 BCE). The reason the virus hasn’t changed is it has a low antigen density, meaning that only a few viral particles enter our cells (to cause illness). Because of this low density, our immune system takes longer to recognize the virus as a pathogen/hazard.
If an unvaccinated individual or someone who has never had measles is exposed to the measles virus, they will likely get sick. This is what is happening in Ohio right now. Exposure occurs through droplets (like when someone sneezes) and the air. Measles is crazy-wicked stable in the environment. Imagine I walk into the local grocery store and I have measles — I will be contagious 3-5 days before symptoms occur. Every time I breathe out, I will be releasing viral particles into the environment. And those viral particles can float around in the air for 2 hours (yes, 120 minutes) and remain infectious. So if I am there at 10 am and you walk in at 11 — we may not see each other in the store, but my measles virus particles are there and they can cause you to get sick. Similarly, if I sneeze in the produce section, the viral particles in my sneeze juices/droplets can survive on the surface of (say) an apple for up to 2 hours. So you could take my virus home with you on that apple and infect your family.
This virus is so so so contagious!
Symptoms of measles include a high fever (as high as 105*), cough, runny nose (also known as coryza), red & juicy eyes (also known as conjunctivitis), and Koplik spots.
Koplik spots are the pathognomic enanthema of measles (great word… pathognomic enanthema — it is pathognomic = specifically characteristic or indicative of a particular disease & enanthema = an ulcer or eruption of a mucus-secreting surface inside the mouth). These Koplik spots occur in the mouth and are considered the defining diagnostic/pathogenic feature of a measles infection. The spots are named after Dr. Henry Koplik, who first identified the spots in 1896.
Three to five days after symptoms begin, the measles rash appears. The rash is known as a bucket of paint rash — because it looks like someone spilled a bucket of red/pink pain over the head of the sick person’s head. The rash appears to drip down the body (starting on the head and then covering the face, neck, trunk, and arms/hands).
FUN FACT: the rash is actually caused by your immune system, which is killing cells in your body that have been infected with the virus.
So unlike pox viruses, where the pox/rash is the virus itself, the measles rash is a sign of your immune system working. It is killing cells in your body in order to defeat the infection.
Measles is among the leading causes of childhood morbidity and mortality worldwide.
About 1 in 1000 measles cases will develop acute encephalitis (swelling of the brain), which often results in permanent brain damage or deafness.
One to three in 1000 measles cases will die from respiratory or neurological complications.
But do you know what really scares me about measles?
Is the ability of the virus to suppress one’s immune system. Yes, measles can cause a form of immune system amnesia. After an individual has recovered from measles, they may be immunocompromised for weeks or even months. A measles infection can literally erase/destroy your immune memory. It is like erasing a hard drive. All documents, saved files, games, apps, EVERYTHING is gone. Your body can rebuild the immune system, but it will require you to get sick and rebuild immunity again. It also leaves a person vulnerable to all sorts of secondary infectious following their illness with measles.
This immune system amnesia following measles is so common that following a vaccination campaign there is a subsequent decrease in overall mortality at the population level. The vaccine protects individuals from becoming ill with a measles infection but also protects the immune system. That immune system protection leads to a decrease in mortality.
Think about that for a minute…
When measles is spreading in a community, the overall mortality rate will increase because of the damage done to the immune system by the virus. When we prevent people from getting measles — through vaccinations — we protect the immune system and fewer people die.
Amazing & scary.
Measles is a disease that we need to prevent. And thankfully, we have had a safe and effective vaccine since 1963.
The end.
The measles vaccine is safe and effective. It protects you and your immune system.
If only it were that simple…
On Monday, I’ll have another post (part 2 in this series focused on measles) that is all about the vaccine — its development, safety & effectiveness, controversies surrounding it, and more. Stay tuned. Be sure you are subscribed so you don’t miss Measles: Part 2 — the vaccine.
And if you have questions about measles, please let me know.
