WASHINGTON, May 6 (Xinhua) -- A total of at least 764 measles cases have been confirmed in 23 states of the United States since the beginning of this year, the U.S. Centers for Disease Control and Prevention (CDC) reported on Monday.

This is an increase of 60 cases from the previous week, and the greatest number of cases reported in the country since 1994 and since measles was declared eliminated in 2000, according to the CDC.

New York City has seen one of the strongest outbreaks as 41 of the new cases happened there. As of April 29, there have been 423 confirmed cases of measles in Brooklyn and Queens of New York City since October, according to New York City's health authorities.

In October of 2018, an unvaccinated child who traveled to Israel returned home in New York with the disease.

As of May 1, 40 confirmed measles cases have been reported in California, according to the state's Department of Public Health.

Pennsylvania reported five cases as of May 2, becoming new to the list of states with measles cases.

Measles is a virus that causes fever and a rash. It is highly contagious and anyone who is not vaccinated against the virus can get it at any age.

Six of the 13 outbreaks in the country were associated with communities with lower immunization rates, according to the CDC.

Measles can be prevented with a vaccine, which is safe and effective, but a significant factor contributing to the outbreaks in New York is misinformation in the communities about the safety of the measles/mumps/rubella vaccine, as some organizations are deliberately targeting these communities with inaccurate and misleading information about vaccines, according to the CDC.