A person in Mexico has died after contracting a strain of bird flu that hasn¡¯t been confirmed in humans before, the World Health Organization said Wednesday.

The virus was detected in a 59-year-old who had been hospitalized in Mexico City. The person died one week after developing a fever, shortness of breath and diarrhea. It¡¯s the first lab-confirmed case of a person contracting a form of bird flu known as H5N2, the WHO said in a statement, raising questions about a strain that has largely been under the radar. The current bird flu outbreak in U.S. dairy cows is being driven by a different strain ¡ª H5N1.

The patient, who lived in central Mexico, had no history of exposure to poultry or other animals and had underlying medical conditions. The Mexican government doesn¡¯t know where the patient was exposed to the virus, though the strain of avian influenza has been reported in poultry in the Mexican state where the person lived.