FRESNO, Calif. – The rustic tent cabins of Yosemite National Park – a favorite among families looking to rough it in one of the nation's most majestic settings – have become the scene of a public health crisis after two visitors died from a rodent-borne disease following overnight stays.

On Tuesday, park officials sent letters and emails to 1,700 visitors who stayed in some of the dwellings in June, July and August, warning them that they may have been exposed to the disease that also caused two other people to fall ill.

Those four people contracted hantavirus pulmonary syndrome after spending time in one of the 91 "Signature Tent Cabins" at Curry Village around the same time in June. The illness is spread by contact with rodent feces, urine and saliva, or by inhaling exposed airborne particles.