Indiana health officials are warning families heading into spring break that travel could increase the risk of measles exposure. The concern comes as cases rise in southern states.

Measles is highly contagious and can spread through the air, particularly in crowded places such as airports, planes and buses.

Julie Nagel, director of nursing at the Hamilton County Health Department, said travel puts people closer to outbreaks.

"We are fortunate here in Indiana that we do not have cases," she said, "but places like South Carolina, Florida, places that people like to travel, have high cases of measles."

Federal health officials added that the best protection is vaccination, but rates have slipped slightly nationwide, raising concern about a potential spread.

Nagel said measles is one of the most contagious viruses people can encounter, and the choice to remain unvaccinated presents a major risk.

"In fact, if you're in a room of ten unvaccinated people, nine of them are likely to develop measles," she said. "Again, very contagious. It spreads through the air, and it can linger in the air for up to two hours."

Doctors say anyone unsure of their vaccination status should check with a provider before traveling. Health leaders add that developing protection from measles after getting the vaccine takes about two weeks, making early planning critical as Hoosier families prepare to leave for spring break.

Source: Public News Service