CHARLESTON, W.Va. (AP) — A West Virginia hospital has confirmed the first known case of measles in the state since 2009, health officials said Monday.

The Monongalia County Health Department said WVU Medicine alerted officials Sunday that an adult patient living in the county tested positive for the viral infection. Health officials have not pinpointed exactly where and how the patient was exposed but said the person had recently traveled abroad.

The patient — who was partially vaccinated against measles, having received one of two doses — had developed symptoms, sought medical treatment through the WVU Medicine system and was instructed to stay home while awaiting lab results.

One of the world’s most contagious diseases, measles can lead to potentially serious complications.

Dr. Brian H. Huggins, the county health department’s incoming health officer, said the department is working with the hospital to identify people who came into contact with the patient.