The number of measles cases across the US rose for the third week in a row, bringing the total to 555 — the highest number in the past five years, the Centers for Disease Control and Prevention said Monday.

If the outbreaks — which prompted the Big Apple to order mandatory vaccinations last week — aren’t brought under control, health experts fear the number of cases in 2019 could set a 20-year record since measles were supposedly eliminated from the US.

“From Jan. 1 to April 11, 555 individual cases of measles have been confirmed in 20 states. This is the second-greatest number of cases reported in the US since measles was eliminated in 2000,” the CDC said in a statement.

States that have reported cases to CDC include New York, where there have been outbreaks in Brooklyn and Rockland County, New Jersey, Connecticut and Massachusetts.

There have also been cases in California, Colorado, Florida, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, Missouri, Nevada, New Hampshire, Oregon, Texas and Washington.

Experts say the debunked link between vaccines and autism pushed by the anti-vaxxer movement led to an increase in cases, and that misinformation about vaccine safety spread in some Hasidic communities was another contributing factor.

Meanwhile, a group of anti-vaccination parents claims city officials overstepped their bounds — and violated their religious beliefs — by imposing an emergency order last week making measles vaccinations mandatory, according to a lawsuit filed early Monday.

The city hasn’t revealed all the information surrounding the current outbreak, including the number of cases, the suit claims.