04/07/2014 07:36 EDT | Updated 06/07/2014 05:59 EDT

Think We're Rid of Measles? Think Again

Over the last few weeks, the numerous outbreaks of measles in Canada have led many public health officials and microbiologists to shake their collective heads. The reason is simple: this should not be happening. Of all the pathogenic viruses, this one has been on our radar for nearly 200 years as has been the knowledge of how to prevent infections: vaccination.

Back in the early 1800s, merely thirty years after the discovery of Edward Jenner led to the dawn of vaccines; measles was identified as the next virus to be stopped. It didn't quite go as well as expected. The first tests were unsuccessful although the results did not discourage the efforts. A century later, researchers understood the dynamics of vaccination and knew success was close. By the 1960s the solution was found and public health officials were ready to go on the offensive and eradicate this illness.

The picture was relatively good as many countries saw the number of infected patients drop to negligible levels. In Canada, the incidence was close to zero by the late 1990s. There was little doubt victory was apparent and soon, like smallpox, the world would be rid of the virus and the disease.

But then the tide turned. During the first few years of the new millennium, outbreaks were seen in the Netherlands, Italy, Marshall Islands, and eventually, the United States. Canada's turn came in 2011 with over 700 cases.

This year, measles is back and has so far infected about 350 Canadians across the country. The numbers are still relatively low compared to 2011 but the distribution is a major concern. There is no hot zone in this case; the virus is a national problem. Worse, due to the understandable lack of attention to the virus, most Canadians have little understanding of the implications of this disease to their community as well as to themselves. What is certain is many don't realize that infection is far more than just a rash.

Biologically speaking, the virus is a member of the paramyxovirus family. Practically speaking, it is similar in design to the flu. It has a centre core of proteins and genetic material surrounded by a lipid envelope. In the environment, it's relatively easy to kill with simple soap and water and has a limited survival on surfaces, about two hours. Proper hand hygiene and environmental cleaning can all but stop the spread via these routes. Unfortunately, like the flu, the virus is spread via the respiratory tract meaning masks and other preventative measures are necessary when infected.

This is where the similarities with influenza end and the real problems begin. An individual with the flu could potentially infect 1-3 people in any given environment. Measles, on the other hand, can infect between 12-18 people if the population is unvaccinated and about six to seven in a partially vaccinated population. The reason is due to the nature of infection once the virus is inside the body. Unlike the flu virus, which has only one route of entry into cells, measles can utilize three. Also different is where the viruses can be found. Flu is usually limited to the respiratory tract. Measles, however, can migrate to the lymph nodes, the spleen, the bladder, and possibly the nervous system, all before any symptoms occur.

After some 12 days, the virus returns to the respiratory tract where symptoms of flu-like illness begin. Coughs, fevers, runny nose, and even eye redness are common and can last a few days. In the meantime, bluish-gray specks called Koplik spots arrive. This is usually the first indication of a measles infection some two weeks after exposure.

As this is happening, the body is learning to fight the virus. By the time the Koplik spots have arrived, the immune system is ready to go on the attack. Within a few days, that onslaught is manifested as a bright red rash that covers the body. It's caused by a flood of immunological cells all working to find the virus and kill it. After a few days, the skin returns to normal although it may take another week before the infection is completely cleared and the person is no longer infectious.

For those counting, that's an entire month of preventable misery but this may only be the beginning of trouble. Inasmuch as measles is a survivable infection, when numbers start to add up, complications, both short term and long, begin to emerge leaving many with severe disease that could kill.

Because the virus can use three different measures to infect cells, it can find its way into several parts of the body and cause havoc. Around 5% of the population will see additional symptoms, including diarrhea, earache and even pneumonia. About one in every thousand will develop inflammation of the brain, encephalitis or other neurological complications leading to death. Other more rare problems include skin disorders, renal failure, inability to thrive, appendicitis, hepatitis and even heart failure. Though none have been seen as of yet this year, if the case numbers continue to rise, these other conditions will eventually be seen.

Even after the infection is over, problems may still occur. The virus is known to persist in the body and may lead to a number of other problems, including a lethal condition known as subacute sclerosing panencephalitis. Other possible concerns include the development of autoimmunity that causes the destruction of myelin, seen typically in neuromyelitis optica as well as multiple sclerosis.

Clearly, of all options for prevention, none is more effective than vaccination and should be regarded as the primary choice. Yet, there will inevitably be those who are unvaccinated either through choice or necessity and they will present the highest risk. Should this be the case, the best routes to prevent infection are based on avoiding infection altogether.

  • Do not travel to endemic areas.
  • Do not congregate with people who display obvious symptoms of measles.
  • Avoid interaction with other unvaccinated travellers until 18 days after return
  • Do not trust any alternate vaccines not based on measles biology
  • Always adhere to the strictest hygiene practices

One of the problems with a re-emerging illness is the lack of public appreciation of the once known extent of damage posed by the infection. In the case of measles, the introduction and widespread use of the vaccine should have allowed us to put our fears away and look forward to a measles-free world. But now that future is at risk. The reasons are varied and will be explored over the coming years but in the meantime, the best way to be prepared is to be informed. After all, measles is so much more than a red rash. If it regains traction in our communities we will certainly be facing even more problems in the future.


Measles In Canada