Measles has been eliminated in all of the Americas, from Canada to Chile, the World Health Organization declared Tuesday.
It's the first time the highly contagious virus has been eliminated in an entire region, although it has been eliminated in individual countries, such as the United States.
It was sustained vaccination campaigns that got the job done, WHO said.
"Today we say bye-bye to the indigenous transmission of measles," Carissa Etienne, director of the Pan American Health Organization (PAHO), the Americas arm of WHO, told a a meeting of the organization in Washington.
"We celebrate this historic day in which the scourge has been eliminated," Etienne added.
Smallpox was eliminated from the Americas in 1971; polio was eliminated in 1994 and rubella, also known as German measles, was eliminated in 2015.
Smallpox was eradicated globally in 1972. No other infection has been eradicated, but WHO is trying hard with polio.
"After a year of targeted actions and enhanced surveillance, the last case of measles in Brazil was registered in July 2015," PAHO said.
Eradication and elimination are two different things. When a disease is eradicated, it doesn't exist anywhere. Elimination means there are no more homegrown cases but the infection can still be imported from elsewhere to cause outbreaks.
"It is my hope that other regions are encouraged by the lessons of the Americas," WHO director-general Dr. Margaret Chan told the meeting.
Chan said it took "dedicated financing and strong political commitment" to keep the needed immunization programs going across the region — including vaccination campaigns in remote forests and in areas made dangerous by conflict.
"Many have risked their lives and continue to risk their lives to save the lives of others," said Dr. Merceline Dahl-Regis, the former chief medical officer of the Bahamas who chaired the committee leading the elimination effort.
There's been a measles vaccine since the 1960s. Before mass vaccination began in the 1980s, measles killed nearly 2.6 million people a year, WHO says.
"Measles is one of the most contagious diseases and affects primarily children. It is transmitted by airborne droplets or via direct contact with secretions from the nose, mouth and throat of infected individuals," WHO said.
Symptoms include high fever, a distinctive rash and irritated eyes. It can kill, and can causes severe complications including blindness, encephalitis, severe diarrhea and pneumonia.
Last year, 244,704 measles cases were reported worldwide, WHO says. That means every country risks imported cases, Etienne noted.
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"We cannot become complacent with this achievement, but must rather protect it carefully. Measles still circulates widely in other parts of the world, and so we must be prepared to respond to imported cases," she said.
"It is critical that we continue to maintain high vaccination coverage rates, and it is crucial that any suspected measles cases be immediately reported to the authorities for rapid follow-up."
The U.S. fought off an outbreak in 2014 and 2015 that started with an imported case in California's Disneyland. At least 147 people were infected.
Holes in vaccine coverage are to blame for outbreaks, health officials say. Nearly 9 million U.S. children are not fully vaccinated against measles and risk getting infected, according to a 2015 report.