SAN FRANCISCO - One person died and another was sickened after contracting the rare hantavirus while vacationing recently in Yosemite National Park in the northern part of the US state of California, local media reported on Thursday.

The latest two infections bring the total number of hantavirus cases in the state this year to four, local daily newspaper San Jose Mercury News said in a report.

Public health officials suspected that the two California residents might be infected possibly after being exposed to mice droppings or urine that contained hantavirus in the park.

Breathing small particles of wild mice urine or droppings that have been stirred up into the air is the most common means of acquiring hantavirus, they said.

The illness usually starts one to six weeks after exposure to the virus with fever, headache and muscle ache, and progresses rapidly to severe difficulty in breathing and, in some cases, death.

Since the rare rodent-borne disease was first identified in 1993, there have been 60 cases in California and 587 cases across the United States. About one third of reported cases in California were fatal.

The two fresh cases have prompted public health officials in California to urge the residents to take precautions at home as well as at places of work and recreation.

"Hantavirus is a rare but serious disease spread by rodents," Ron Chapman, director of California's Department of Public Health, said in a statement issued Thursday.

"This disease can frequently become fatal, but there are steps you can take to reduce your exposure," added Chapman.

Individuals should take steps such as avoiding areas where wild rodents are likely to have been present, while they are in wilderness areas or places that harbor mice, health officials said.

Authorities at Yosemite National Park, a popular attraction for tourists, have increased preventive measures, including inspection and cleaning of rooms and cabins, to reduce the risk of hantavirus exposure to visitors.