With springtime comes spring cleaning, which means it’s a good time to talk about hantavirus.
Hantavirus is a family of viruses that are carried by rodents. Different strains can be found in different places around the world. In Colorado and the Southwestern U.S., the virus strain is Sin nombre (or Spanish for ‘no name’), and it’s carried by deer mice.
“It’s important here in Routt County because we have the second highest number of hantavirus cases in Colorado,” said Lauren Bryan, an infection preventionist at UCHealth Yampa Valley Medical Center. “We also have a fair amount of deer mice.”
Since 1993, Routt County has had seven documented cases of hantavirus, second only to La Plata County. That may not seem like many, until you consider the high mortality rate associated with the virus: out of 151 documented cases in Colorado since 1993, there were 41 fatalities.
Peak season for the virus is spring and early summer.
“That’s when people are starting to go in and clear out their sheds and garages where deer mice have been nesting,” Bryan said. “The bodily fluids from the mice carry the virus. So if people sweep up excrement or touch dead mice or get bitten, they may be exposed.”
In about a third of all cases, people never even see a mouse.
“So any time you’re going in and clearing out those areas, it’s important to be aware of it,” Bryan said.
On average, symptoms start two weeks after exposure, but can hit anytime between one and six weeks. Fever and chills may be experienced, but everyone who is infected has severe leg, hip and back pain.
“That’s the really distinct feature of the virus,” Bryan said. “You may not get the other symptoms, but you will have leg or hip or back pain that doesn’t go away with ibuprofen or Tylenol.”
The virus can progress quickly, causing inflammation in the heart and lungs, which may result in fluid build up in the lungs and eventually death.
Anyone experiencing symptoms of hantavirus should seek medical attention immediately: there’s no cure for the virus, but various treatments – such as blood pressure support – can help counteract effects of the symptoms. A simple blood test can show the presence of the virus.
There is no vaccine for hantavirus, but precautions can be taken to prevent infection.
“Ultraviolet light actually kills the virus,” Bryan said. “Open up and air out the spaces you’re trying to clean and let the sunlight in before you go in and do anything.”
Keep mice from nesting in the first place by caulking and rodent-proofing your home, and trap mice that have already gotten inside.
“Handwashing is important too, as some transmission happens when people clean up, and then touch their mouth, nose or food they’re eating,” Bryan said.
The virus can also be inhaled, but there currently aren’t masks that have been shown to prevent contamination from the virus.
One positive is that the virus cannot be spread by people, pets or rodents purchased at a pet store.
And remember that oftentimes, instead of seeing the small, brown deer mice, you’ll just notice signs of their presence.
“You may see nesting materials, such as straw, or excrement,” Bryan said. “Or the mice may chew stuff up and make holes in dog food bags and other food containers.”
All of those efforts to keep mice out of the house pay off in other ways: mice also carry ticks, which can spread diseases such as Colorado Tick Fever and Rocky Mountain Spotted Fever.
“Rodent proofing areas is really important for a number of reasons,” Bryan said.
This article appeared in the Steamboat Pilot & Today on April 29, 2019.