The US declared in 2000 that measles was eradicated, meaning the disease was no longer present in the country year-round.

But more than 800 cases have been recorded so far this year — the largest outbreak in the US since 1994.

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(Reuters) - The United States so far this year has recorded 764 cases of measles in 23 states, its largest outbreak since public health officials in 2000 declared the disease eradicated, according to the Centers for Disease Control and Prevention.

The CDC on Monday released updated figures on the number of cases recorded so far this year, reporting another 75 cases last week. That brings the total to 839 cases in 2019, making it the worst outbreak since 1994.

The following are key facts about the outbreak: