Among the confirmed cases, 43 were not immunized against the highly contagious disease.
Experts can't say for sure where the next outbreak might be.
Measles infections in Europe hit a decade high in 2018, despite more children than ever before receiving vaccinations.
Public health officials have attributed the outbreak to vaccine coverage of less than 50 percent of the population when the outbreak began.
The Washington State Health Department hasn't identified "patient zero" in the Clark County measles outbreak that has tallied 50 confirmed cases in Clark County and 55 total cases in Washington and OR since January 1.
The "anti-vaxxers" movement still thrives in many pockets of the United States.
Graham said that "patient zero" is not a term the Health Department even uses.
More than 80,000 people caught measles in 2018 across 47 European countries, 15 times as many as two years before.
"Clusters of vaccine refusers are serving as tinder for these fires", Omer says.
U.S. crude oil imports, exports up last week
The fund would receive income accrued by state-run oil firm PDVSA's U.S. unit Citgo Petroleum Corp since last month, when U.S. U.S. distillate stocks fell by 2.3 million barrels, while inventories of other refined fuels dropped by 2.9 million barrels.
Adult vaccination numbers in the county also rose.
Measles immunisation coverage has fallen in a dozen European Union countries since 2010, and 70 percent of countries with the lowest vaccine confidence in the world were in Europe.
"There's no reason we should be having this outbreak", says Melnick.
Dr Zsuzsanna Jakab, WHO regional director for Europe, said: "The picture for 2018 makes it clear that the current pace of progress in raising immunisation rates will be insufficient to stop measles circulation".
"A lot of the carriers are young adults and children who are travelling and then bring it back home".
Statewide in Washington, orders for measles vaccine jumped about 30 percent in January compared with the same month previous year, climbing from 12,140 doses to 15,780 doses, figures showed.
Fifty of the confirmed cases are in southwest Washington, one is in the Seattle area and four are in the Portland, Oregon metropolitan area. "We're hopeful and any time we see that there are no new exposure locations that's helpful", said Marissa Armstrong, spokeswoman for the Clark County Public Health.
Part of the challenge facing public health officials is that Canada doesn't have a national vaccination registry and provinces track vaccine rates differently, meaning it can be hard to get an accurate, real-time sense of how many people are up-to-date on their shots - and where pockets of low immunization are.
Vaccination rates in King County - where the other single measles case in Washington was is located - also went up. The Philippines is also battling a major outbreak, with more than 1,800 cases and 26 deaths.