The National Park Service said the victim was a California resident who contracted hantavirus pulmonary syndrome after visiting the park in June, the Los Angeles Times reported Monday.
The two people who died, a third person confirmed having hantavirus and a fourth who may have contracted the disease stayed in tent cabins at the park's Curry Village in June, the Park Service said in a statement.
"An outreach effort is currently under way by the park concessioner to contact visitors who stayed in 'Signature Tent Cabins' at Curry Village from mid-June through the end of August," the service said in the statement. "These individuals are being informed of the recent cases and are being advised to seek immediate medical attention if they exhibit any symptoms of hantavirus."
The symptoms,which manifest between one and six weeks after exposure, include fever, headaches and muscle aches, the Times said. The syndrome progresses to severe difficulty in breathing and possible death, officials said.
Hantavirus pulmonary syndrome is caused by a virus people contract after coming into contact with urine, feces or saliva of infected rodents, mainly deer mice.
Park Service officials said Yosemite National Park has conducted more rodent trapping and increased rodent-proofing and trapping efforts in tent cabins and buildings throughout the park.