The US has confirmed 695 measles cases so far this year, the highest incidence recorded since the country declared it had eliminated the virus in 2000, the US Centres for Disease Control and Prevention says.
The resurgence of the contagious disease is linked mainly to large outbreaks in Washington state and two in New York that began late last year, the agency said in a statement on Wednesday.
"The longer these outbreaks continue, the greater the chance measles will again get a sustained foothold in the United States," the agency's statement warned.
Although the disease was eliminated from the country in 2000, meaning the virus was no longer continually present year round, outbreaks still happen via travellers coming from countries where measles is still common, the CDC says.
As of Wednesday, the number of measles cases so far this year exceeds the 667 cases reported in all of 2014, which had been the highest annual number recorded since the elimination in 2000.
The largest outbreak has been in New York City where officials on Wednesday said 390 cases had been recorded since October, mostly among children in Orthodox Jewish communities in Brooklyn, New York City.
