When you have a runny nose, a cough, muscle aches and a high fever, you may brush them off as symptoms of the flu. However, if these symptoms come with a skin rash and tiny white spots inside your mouth, that’s when it points to something much worse, and extremely infectious: measles.
“Measles is one of the most contagious viruses known,” warns Dr. Gregory Wallace, team lead of the measles, mumps, rubella and polio team in the epidemiology branch of the U.S. Centers for Disease Control and Prevention (CDC).1
As a matter of fact, if a person has it, 90 percent of the people close to him or her who are not immune (meaning you have already contracted the disease) will also become infected.2 But how does the measles virus spread so rapidly, and why is it so contagious?
The Measles Virus Is Highly Infectious
In the same category as influenza, measles is a respiratory virus that can be transmitted by coughing, sneezing and direct contact with infected nasal or throat secretions.3 People with measles are contagious from roughly four days before to four days after the rash appears.4
The measles virus can infect you when it gets into your lungs and replicates on the linings, called epithelia. Immune cells rescind incoming invaders and kill off infected cells in your epithelia.
However, it turns out, as the measles virus hits the lungs, it doesn’t stay put to breed; it boldly hijacks an immune cell and gets a ride into your immune system, making new viruses that infect other immune cells along the way.
The virus-laden cells then sneak from the windpipe to your lymph nodes, which are overflowing with more immune cells, and then from the lymph nodes, this “hijacking spree” spreads throughout your body. If the measles virus has managed to find its way into your nervous system, it can cause permanent brain damage.5
Most importantly, measles has a brilliant way of transmitting itself, which makes it really easy to get out of your body and infect other people.
How Is Measles Spread?
When you get measles, the virus lives in your nose and throat mucus.6 “The measles virus uses the trachea as a trampoline,” says Roberto Cattaneo, Ph.D., professor of biochemistry and molecular biology at the Mayo Clinic. A single sneeze or cough will scatter the virus through the air in high viral quantities, unlike other respiratory viruses that have to travel more just to get out of the host.
Once out, the measles virus can live in an airspace or on surfaces for up to two hours and still remain contagious — one of the main reasons it spreads very quickly.7
The Disturbing Mortality Rate of Measles
On a global scale, there were 114,900 cases of measles deaths in 2014 — about 314 people died every day, or 13 died every hour.8 In countries where measles is said to be largely eradicated, such as the U.S. and Canada, cases imported from other countries continue to be a main source of infection.9
The World Health Organization (WHO) reported that the measles death rate in the U.S. is exceptionally low — on average, around 0.3 percent from 1987 to 2000, and with only 84 measles cases spanning 14 states in January 2015.10 However, this is not the case for other countries.11
A devastating majority (more than 95 percent) of measles deaths occur in underdeveloped countries, including India, China, Pakistan, Mongolia and Sierra Leone, due to low capita income and poor health infrastructures. In addition, overcrowding in residential areas in these countries increases the risk for infection, transmission and mortality rate.12
In a much wider perspective, the death rate for measles is not the only debilitating statistic: measles is also one of the top causes of disability among young children worldwide due to severe complications, leaving an infected child deaf or mentally disabled.13 At the end of the day, measles is not just a highly infectious virus that kills; this serious disease can cause permanent damage to your health and affect your quality of life, even if you survive it.