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 , who considered the contagious infectious disease eliminated in the United States in 2000 . The outbreak in Ohio began with a group from Christian Aid Ministries , who went on a mission trip to the Philippines earlier this year , health officials say . Philippines is experiencing a very large measles outbreak ; at least 20,000 confirmed and suspected cases have been reported in the Asian nation . Four people who were on the mission trip became infected , according to Pam Palm , the public information officer for Knox County Health Department , and the disease has since spread to 62 others in the Amish community . Knox County has 40 cases . Palm said the first few cases were initially misdiagnosed as dengue fever , a testament to how few cases of measles doctors usually see . `` Because of the success of the measles vaccine , many clinicians have never seen measles and may not be able to recognize its features , '' Dr. Julia Sammons wrote in a commentary published in April in Annals of Internal Medicine . Ohio health officials have immunized nearly 800 people with the MMR ( measles , mumps , and rubella ) vaccine since the outbreak began . `` The Amish who are family members and acquaintances of those who now have measles have been extremely cooperative in a willingness to get vaccinated , '' Jackie Fletcher , director of nursing for the Knox County Health Department , said in a statement . `` And those who currently have measles have been staying home . '' California , another state 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 can not 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 . Fletcher said many of the measles patients her staff are seeing are `` really sick . '' Symptoms 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 . `` Although most of us do n't realize it because it is so rare in our country , measles is a serious disease , '' CDC director Tom Frieden wrote on CNN in 2013 . `` Measles is so contagious that if one person has it , 9 of 10 people close to that person who are not immune will also become infected . '' Were you at this concert ? You might have been exposed to measles . 5 things to know about measles .
The contagious disease was considered eliminated in the U.S. in 2000 . Hide Caption 1 of 10 Photos: Measles is one of the most contagious infectious diseases .