There are a couple of different factors that can contribute to a measles outbreak, but in modern times the most common is usually a high concentration of unvaccinated people. The measles vaccine, which is given to school-aged children in many countries, is generally very effective against the disease, and in most cases it prevents isolated infections from rising to the level of a true outbreak. Even in largely vaccinated communities outbreak can take hold, though, usually when the virus exploits what’s known as a “weak link.” In these situations, a person who is not immune acts as a carrier, and infects people in the near vicinity who similarly lack immunity. In places where vaccination is not common, the biggest factors for outbreak are usually poor hygiene and lack of proper nutrition. The disease is airborne, but taking precautions like washing hands regularly can help prevent its spread. Additionally, people who are otherwise healthy and strong are more likely to ward it off or at least survive infection.
Outbreak Basics
Measles is a highly contagious viral infection of the respiratory system. On a very general level, a measles outbreak spreads when people breathe in infected droplets that are then exhaled through coughing or sneezing. The virus lives and flourishes in the mucus of the throat and nose of sufferers. Infection can also occur if someone touches a surface where infected droplets have landed and then inadvertently touches the mouth, eyes or nose. The virus can live on surfaces for several hours, which enables it to infect many new hosts as they come into contact with it.
From a medical perspective, an “outbreak” is usually understood to be a situation in which more reported cases of a specific disease occur within a defined period time than is normal, average, or expected. A lot depends on the region, but in most cases one or two people contracting measles isn’t considered a true outbreak. There isn’t usually a defined numerical threshold for determining what qualifies, but examples include multiple cases at the same school, a sudden surge in measles-related hospital admissions in a particular area, and an increase in suspected cases within any given community. In most cases, finding the cause is an important part of stopping the spread and restoring health.
Unvaccinated Populations
Scientists first developed a vaccine for measles in 1963, and many countries have widely adopted it in the years since. Vaccines work by introducing a small amount of deactivated or dead virus to a person’s bloodstream, which triggers an immune response and subsequent immunity. Should a vaccinated person then come into contact with a live strain of the virus, his or her body can mount a quick defense and infection doesn’t typically happen. Outbreaks are accordingly somewhat rare in populations where most people have been vaccinated against the virus. In parts of the world or local communities where vaccination isn’t common, though, the chance of an outbreak is much more likely.
Finding a “Weak Link”
A measles outbreak can happen in areas where a majority of people are vaccinated, usually when the virus finds what’s known as a “weak link.” An example of this is a 2008 outbreak in California in which a child's parents chose not to have him vaccinated . The boy then traveled overseas, came into contact with the virus, and brought it home. Before anyone realized that he was infected, he had exposed hundreds of people, including several other children and educators who had not been vaccinated and later contracted the disease.
Health and Hygiene Concerns
Prior to the development of a successful measles vaccine, approximately 130 million people a year contracted the virus. These numbers have gone down dramatically, but measles outbreaks still happen in parts of the world that haven’t adopted widespread vaccination. Most of the time, the disease’s spread is helped along by two factors: poor health of the victims and substandard hygiene, either in homes or in entire communities.
Nutrition is often really important to staying healthy against any sort of viral attack. People who lack adequate vitamin A, for instance, appear to contract the measles virus more easily than others, which can leave sufferers more susceptible to severe symptoms of the disease, including pneumonia, dehydration and blindness. Access to clean water and proper sanitation is also usually a good way to prevent the virus from spreading as fast from person to person.
Knowing What to Look For
Measles symptoms usually start appearing about 10 days after coming into contact with the virus. Symptoms typically begin as a runny nose, elevated temperature, and cough. Optical sensitivity to light is also common as the infection progresses, and the whites of the eyes also begin to appear red. After three to seven days, the symptoms become more severe and people suffer a higher temperature, which often reaches 105°F (40.5°C). A red, blotchy rash appears over the infected person's body — even, possibly, on the palms of the hands and soles of the feet — and white spots may appear on the gums and elsewhere inside the mouth.
Anyone who suspects that he or she has contracted measles is usually advised to seek immediate medical care. The disease is very contagious, and medical professionals and health officials usually try to isolate live cases in order to prevent true outbreaks from developing.