It all started in December when some visitors to Disneyland were exposed to someone with the measles virus.
Many of them were not vaccinated, and health experts say containing the outbreak will depend on how many un-vaccinated people get the measles shot.
Now FOX 10 has learned of a possible measles case at a Scottsdale elementary school through a letter sent home to parents.
A relative of a student at Kiva Elementary School is suspected of having measles, to be extra cautious the student's family alerted the school, and they are following all safety precautions.
"I am thrilled that they let us know, it was their obligation, and they fulfilled that obligation," said a relative of a student at the school.
The student at Kiva isn't showing signs of the contagious virus.
"MY children have been vaccinated, so they have got all the doses they need, so I don't really have any concerns about their safety," said a parent of a student at the school.
According to the Arizona Department of Health, the vast majority of students have been vaccinated. Schools require it, however in Arizona parents can get an exemption based on their personal beliefs.
State records show in Maricopa County 1 in 20 kindergartners are exempt.
At Kiva Elementary in Paradise Valley, about 2 1/2 percent of kindergartners had a personal beliefs exemption last year. In a letter sent home to parents, the school emphasized that the student's relative is only suspected of having measles.
"We wanted to make sure that the specific community and those parents heard from us first what is and what is not factual," said Kristine Harrington, a spokesperson with the Scottsdale Unified School District.
Because of the outbreak, the county has seen a big increase in suspected cases of measles.
"We have put out the word to our healthcare providers to think of measles when they see a rash illness, so we are not surprised that doctors are calling us with suspected cases," said Dr. Rebecca Sunshine with the Maricopa County Department of Public Health.