(CNN) -- Sixty-eight and counting.
An outbreak of measles in Ohio has infected 68 people, adding to what is already an 18-year high of measles cases in the United States.
That's disturbing news for health professionals. The contagious infectious disease was considered eliminated in the United States in 2000.
The outbreak in Ohio began with unvaccinated travelers to the Philippines, the state's Department of Health said Monday.
Philippines is experiencing a very large measles outbreak; at least 20,000 confirmed and suspected cases have been reported in the Asian nation.
California, another state also reporting a high number of measles cases this year, said its outbreak also resulted from people visiting the Philippines.
Visitors may pick up the disease and bring it back to the United States, potentially infecting those who cannot be vaccinated against the measles because they are too young, for example, or who have intentionally remained unvaccinated.
Data released by the Centers for Disease Control and Prevention on April 24 found 129 cases of measles in the United States between January 1 to April 18. That's the highest number of cases recorded for the period since 1996.
Some of the Ohio cases were recorded after that reporting period -- meaning, the total now is undoubtedly higher.
Symptoms of measles usually include fever, cough and conjunctivitis, along with a rash. In rare cases, measles can lead to pneumonia and brain infections, which can be fatal.
This report includes information from an earlier report by CNN's Trisha Henry.