The Centers for Disease Control and Prevention is monitoring the spread of measles in 21 states, including Florida.

The Florida Department of Health said Monday it is investigating a case of measles in an unvaccinated child in Pinellas County.

The other states included are Arkansas, California, Connecticut, Illinois, Kansas, Louisiana, Maryland, Michigan, Missouri, Nevada, New Jersey, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Tennessee, Texas, and Washington, and Washington D.C.

Some 107 people have contracted the measles thus far in 2018, according to the CDC. The number is likely to surpass the 118 reported measles cases from 15 states in 2017.

In 2014, the U.S. experienced a record number of measles cases, with 667 cases from 27 states reported to CDC.

Graph: Number of measles cases by year

Measles is a virus that spreads through the air and by coming into direct contact with someone who has it. Symptoms show up in 10 to 14 days after exposure.

The CDC says measles are still common in many parts of the world, including certain countries in Europe, Asia, the Pacific and Africa. Travelers with measles are capable of bringing it into the U.S.

Related: Unvaccinated child with measles reported in Pinellas County

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