SALT LAKE CITY -- Health officials in Utah are trying to contain a measles outbreak that may have infected hundreds of people who attended two recent community events.
Nine cases in the state have been linked to exposure to one unvaccinated person who contracted the disease in Poland, according to the Salt Lake Valley health department. Epidemiologists have determined that the infected person exposed as many as 1,000 people earlier this month.
Measles is so contagious that if one person has it, 90 percent of those near that individual will also become infected if they are not immune.
To keep the outbreak from spreading, state health officials are urging anyone who attended either event to contact the Utah Poison Control Center to determine if they were properly vaccinated against the measles virus. Those who attended the first event also are being asked to stay at home until April 29, and until May 1 if they attended the second event.
Nationwide, 84 measles cases have been reported this year, the most since 2008, when there were 140 cases, many of which were traced to an outbreak in Arizona started by a Swedish tourist, the Centers for Disease Control and Prevention reported Friday.
Officials say outbreaks also have been reported recently in Minnesota and New Jersey.
"Measles is such a contagious virus, once it finds a cluster of people not vaccinated, it can spread quite quickly," said the CDC's Dr. Greg Wallace.
Measles hasn't been eradicated in the U.S. as smallpox has, but it has been declared eliminated, meaning there aren't sustained transmissions within the country.
Europe, especially France, has been hit by a major outbreak of measles, which the United Nations health agency blames on the failure to vaccinate all children.
Wallace said that as of 2007, most in France only get one dose of the measles vaccine. The World Health Organization says two-dose coverage is needed to stop the spread of the virus.
Utah has an immunization rate of up to 97 percent, health officials said.