Tuolumne County, CA — The National Park Service continues to investigate the recent cluster of Hantavirus cases in Yosemite National Park. According to Tuolumne County Health Officer, Dr. Todd Stolp, there have been six cases of human hantavirus infection identified, one of which remains under investigation regarding the source of the infection.
Dr. Stolp notes that infection with Sin Nombre Virus (SNV) which causes Hantavirus Pulmonary Syndrome is not common. The new cases are in addition to only two others in the past 13 years in which over 10 million visitors to Tuolumne Meadows were not infected. The often causes a pneumonia-like illness. Symptoms usually develop one to seven weeks after exposure to an area infested with deer mice or other rodents, and consist of fever, muscle aches, chills, cough, nausea, and shortness of breath. HPS infection in the U.S. is not transmitted from one person to another, it has been fatal in nearly one third of all cases.
Dr. Stolp says, “The virus has probably been present for many, many years, sustained primarily by the local deer mouse population. It can be expected to remain in this rodent population, so infrequent local Hantavirus Pulmonary Syndrome infections can be expected to continue to occur originating in Tuolumne County.” Most human cases in California have originated from the east side of the Sierras in the Tuolumne Meadows area.
Rodent control in and around the home remains the primary strategy for preventing hantavirus infection. Recommendations can be summed up as:
SEAL UP holes inside and outside the home to prevent entry by rodents. This includes clearing brush and grass from around the foundations of homes.
TRAP UP – Trap rodents around the home to help reduce the population. Dead rodents should be handled with gloves.
CLEAN UP urine and droppings, dead rodents or nests around cabins, barns, sheds, or other outbuildings, food sources and heavy rodent infestations. It is important to follow instructions about how to safely clean up contaminated areas. First, do not stir up dust by sweeping or vacuuming up the materials. One should start by ventilating the area for 30 minutes, first opening doors and windows and then returning to clean the area as follows. Spray the contaminated area with a water-and-bleach solution (approximately one and one-half cups household bleach per gallon of water) while wearing waterproof gloves and wipe up the area with paper towels, allowing the feces and contaminated material to soak for five minutes. Dispose of the towels in the garbage. Finally mop the area with a wet mop.
Dr. Stolp concludes, “The California Department of Public Health, the National Park Service and other public health experts continue to work diligently on the recent cases from Yosemite National Park and will provide further information to the public as information emerges.”California Department of Public Health information news story from August 31st is here.
Yosemite National Park reports in total they have sent out 2900 emails the August 29th “Yosemite Expands Email List” news story is here.