The measles outbreak which started in the Hudson Valley is now the worst in New York State in decades.

Since September, at least 112 people have been diagnosed with measles in Orange and Rockland Counties and 55 people have been confirmed to have measles in the New York City area.

"I would say this is the largest measles outbreak that New York state has had in recent history," New York State Commissioner of Health Howard Zucker told CNN. "If you go back many decades ago when we weren't vaccinating, of course there were probably more outbreaks, but in my memory, I don't know of a measles outbreak that was this significant.

Over 13,000 children have been immunized since the outbreak started, according to Zucker.

In October, it was reported an international traveler with measles visited multiple locations in Rockland and Westchester counties. Among the locations infected with measles was the Costco in Nanuet and Westchester Medical Center.

The Rockland County measles outbreak spread into Orange County in November. Health officials in Orange County later warned that a taxi was exposed to measles. 

Around Thanksgiving, shoppers at the Palisades Mall were potentially exposed to measles. 

Measles is a highly contagious respiratory disease caused by a virus that is spread by direct contact with nasal or throat secretions of infected people. People first develop a fever, then often a cough, runny nose and watery eyes, followed by an appearance of a rash. People are considered infectious four days before to four days after the appearance of the rash.

Symptoms include a fever, rash, cough, conjunctivitis or a runny nose. Symptoms usually appear 10-12 days after exposure but may appear as early as 7 days and as late as 21 days after exposure.

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