The California outbreak likely started when a traveler who was infected overseas with measles visited the amusement park while infectious, according to the Centers for Disease Control and Prevention. But health officials don’t know exactly who the source of the outbreak is.
Genetic analysis of the specimens from 30 California patients showed that the measles was of genotype B3, which is identical to the virus circulating in the Philippines.
The highly contagious disease has been damaging in the Philippines, infecting about 53,000 people and killing 110 people in 2014. The CDC also cautioned that the same virus type has been found in 14 other countries.
How bad is measles around the world?
So far, the United States has 141 reported cases of measles this year — 98 of them from California. Most of the people who’ve become sick with measles were unvaccinated, according to the CDC.
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Source: WHO, does not include data from all countries
After Typhoon Haiyan struck the Philippines in November 2013, the country has grappled with a massive measles outbreak.
In 2013, the country reported 5,799 confirmed cases of the disease. By 2014, that number increased nearly tenfolds to 53,357 cases, according to World Health Organization data. The spread of the virus has been exacerbated by mass migration, with nearly 4 million people displaced by the devastating typhoon.
The WHO and the Philippines Department of Health have been trying to control the outbreak by conducting vaccination campaigns that seek to immunize 11 million children.
According to WHO data, the Philippines has had one of the highest rates and number of suspected cases for measles.
