A Hanta-ed House

"Siri, set a weekly reminder to check for symptoms," I anxiously barked into my phone as the sun tucked in behind the picturesque mountains. This place is beautiful, but it is no bucolic paradise. Lurking in the shadows of this rural home hid my new nemesis, Peromyscus maniculatus. This charmingly cute, white-bellied deer mouse is the primary host for Sin Nombre hantavirus.

Three years earlier, we traded square footage for acreage. The stalls that once were home to horses became storage for our Rubick's cube of unpacked boxes. On a mission to finally conquer the clutter, I slipped on a pair of gloves, strapped on a respirator, and set off to tackle the barn. 

The boxes of memories and heirlooms were now a commune of mating quarters for the ever-growing population of deer mice who lived with us. Every piece of clothing was riddled with holes, every book tainted by urine, and every knick-knack transformed into a fecal rattle. My gloves were wet, the air was speckled with dust particles, and the ground was littered with pellets. 

"You were wearing gloves, glasses, and a respirator - what more could you have done?" asked Dean. I could tell by the tone of his voice that he was anxiously waiting for some scientific affirmation that I was not going to die from hantavirus cardiopulmonary syndrome (HCPS). The trick is, unlike a rabies incident, there are no vaccines or post-exposure prophylactic.

The initial symptoms for hantavirus infection usually show up anywhere from 1 to 8 weeks after exposure. That's up to 56 days of paranoia and overreaction to any flu-like symptoms. Do I have a fever? Are these chills? Is my back sore? This symptom tracking was particularly problematic as December falls within the peak influenza period. 

So, I did what any rational person would do; I set weekly calendar reminders to check for symptoms. My hanta-checklist read like a drug commercial - am I experiencing headaches, dizziness, chills, nausea, vomiting, diarrhea, or abdominal pain? 

The discovery of the Sin Nombre hantavirus is a fascinating tale of coordination across tribal, state, and government individuals and agencies. The virus was discovered in 1993 in the Four Corners region of the United States following an uptick of unexplained cases of respiratory illnesses and deaths in tribal communities in New Mexico. The herculean effort across the agencies resulted in identifying the virus in only a matter of months. For perspective, it took several decades for the first hantavirus, the Hantaan virus, to be isolated.1 The name, Sin Nombre (nameless), was agreed upon following a slew of previous names that all carried significant negative social and cultural implications for the Native American tribes in that region.2 

Ultimately, scientists determined that the virus was not new and that previous undiagnosed cases of respiratory or cardiac illnesses dating as far back as 1959 were a result of hantavirus infection. Interestingly, Navajo tribal stories have identified mice as sources of bad luck and illness since the 19th century.1 The Four Corners region had experienced increased moisture in 1993 that led to abundant vegetation and explosive growth in the deer mice population. This influx of deer mice living near the people in this region is what scientists believe led to the cluster of hantavirus cases. 

Twenty-five years later, I found myself in full panic researching Sin Nombre hantavirus on the CDC website. Eventually, the responsibilities of daily life overcame the existential dread of pathogen exposure, and I pushed forth into the looming kitchen remodel. We swung our sledgehammers in delight as the drywall crumbled, and rays of daylight peeked through the dust-filled house. We plucked the panels off stud by stud until the final pocket of drywall remained, and there, inside the wall, we stumbled upon one of the most horrific sites in a home remodel. 

Hantaviruses typically enter the body through the aerosolization of rodent urine or feces. Once inside the body, the single-stranded RNA virus replicates in the cytoplasm of the host cells. The virus travels through the bloodstream, where it continues to spread, replicate, and cause damage to the heart, lungs, and kidneys. Hantavirus causes blood vessels throughout the body to become "leaky." Lungs fill with fluid when the leaky blood vessels flood the air sacs, and when the virus infects the heart, the damage reduces its ability to pump blood around the body. Failure of the heart to pump and reduction in blood flow causes very low blood pressure (shock), and oxygen is not available to all the cells of the body.3 These events can rapidly lead to the failure of most or all of the organs and, ultimately, death. 

We stood in silence as we stared at the mass grave. I was still within the 8-week range of hantavirus symptoms from the barn clean-out. Now, come to find out we'd been living with 30-40 deer mice slowly decaying atop a cold air return vent inside our wall.

The Sin Nombre hantavirus does not affect the host mice, nor does it spread between people. Its survival is highly dependent on environmental conditions with average survivability of 2-3 days under normal temperature and humidity conditions. Given the recent temperatures leading up to the barn clean-out and the state of decay in our murine gravesite, it is unlikely that we were exposed to live virus. However, when you see that many decaying disease vectors, it's hard to imagine that there isn't some plague lurking in the remains. Despite the pleas from friends and family to burn the house down, we continue to cohabitate with our white-bellied foes despite our best efforts.

Infectious disease experts advise to be cautious, not anxious when it comes to hantavirus. Thankfully, the overall number of cases remains small. If we understand the risks, we can prevent exposure. As the weather warms and the desire to spring clean emerges, you can minimize your chances of hantavirus infection by following these CDC guidelines.

1 https://www.cdc.gov/hantavirus/outbreaks/history.html

2 Bales, F. (1994) Hantavirus and the media: Double jeopardy for Native Americans: American Indian Culture and Research Journal, v. 18:3, pp 251-263

3 https://www.lung.org/lung-health-and-diseases/lung-disease-lookup/hantavirus-pulmonary-syndrome-hps/learn-about-hps.html