Story highlights Arizona officials confirmed 22 cases of measles connected to detention center

46 cases of measles have been reported nationwide so far in 2016, CDC says

(CNN) The Arizona Department of Health confirmed 22 cases of measles as of July 9, representing the biggest outbreak of the season. All infections are directly linked to Eloy Detention Center, an immigration detention facility located in Pinal County.

"We have not identified the individual that brought measles into the facility, but it was likely a detainee, staff member or visitor," said Graham Briggs, of the infectious diseases and epidemiology section of Pinal County Public Health Services District. "Once in the facility it has been spreading amongst both staff and the detainee population." The investigation is ongoing, with public exposure to these cases occurring in the cities of Casa Grande, Coolidge and Eloy.

As of July 8, the Centers for Disease Control and Prevention reported there have been 46 cases of measles nationwide, including the cases in Arizona. In 2015, the CDC recorded 189 total cases nationwide.

Measles is highly contagious, Dr. Cara Christ, director of the Arizona Department of Health Services, wrote in her blog , and 90% of people who lack immunity will get the disease if exposed. People are considered immune if they have been vaccinated or if they've had the measles. Symptoms include fever, red and watery eyes, cough and runny nose. A red, raised, blotchy rash begins at the hairline and moves down the body. Symptoms can appear within seven to 21 days after a person comes into contact with a person who is contagious.

People are contagious before they know they have measles, so more people are likely to get sick in the coming days and weeks, Christ wrote. The virus can be transmitted by direct contact with droplets when an infected person breathes, coughs or sneezes. In fact, the CDC noted, the virus can remain in the air for up to two hours after an infected person leaves the area.

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