Hantaviruses Trivia Quiz

Answer: The Korean War

During the early 1950s, thousands of UN soldiers fighting in Korea started coming down with a strange illness.

Typically, it started with fever, headaches, and chills, but then so does everything. With this, things only got worse. Much worse. Patients could develop bleeding problems and kidney failure, which made military doctors very keen on figuring out what exactly was going on.

The illness became known at the time as 'Korean hemorrhagic fever'. More than 3,000 UN troops were affected between 1951 and 1954 near the Hantan River in South Korea.

For decades the exact cause remained a mystery. Then in 1976, a scientist named Ho Wang Lee discovered the culprit hiding in plain sight. Well, kind of. It IS very small. The virus lived in striped field mice that were just happily a-scurrying around the same countryside where soldiers had camped during the war.

Shortly thereafter, when the virus was finally isolated in 1978, it was named 'Hantaan virus' after the nearby Hantan River, despite the fact that those two words are clearly spelled differently. That discovery ended up giving its name to an entire family of viruses.

Answer: Breathing in dust from rodent waste

Hantaviruses have some nasty habits, none nastier than hanging around rodent excreta. (We all have that one cousin or in-law, though, who's not quite right.) They hitch rides on rodents, particularly mice and rats, and exit the animal joyfully clinging to its urine, droppings, and saliva.

The most common way humans get infected is by breathing in tiny airborne particles contaminated with this waste. Rodent excreta dry out. When you're just minding your own business sweeping a floor, opening an old shed, or rummaging around under the sink, it disturbs the dried-out waste, and that can send microscopic virus particles drifting into the air, a very unwelcome cloud of fecal matter and harmful viruses.

This is why hantavirus infections very often pop up around places that have been closed up for a while. I'm talking about barns, storage sheds, hunting cabins, or that mysterious garage corner where the stuff your wife just can't bear to throw away goes to live out the rest of its life. If rodents have been using the place as a long-term bathroom, stirring up that dust can create a cloud of contaminated particles. If they hit your lungs, you could have a big problem.

Answer: Fever and muscle aches

Early hantavirus infection starts in a familiar way. Fever, muscle aches, headaches, and fatigue. So, just like most things.

People frequently describe deep muscle pain, especially in large muscle groups like the thighs, hips, and back. At this stage, it can look a lot like the flu or another one of your basic viral illnesses, making it annoyingly difficult to diagnose at the time.

After a few days, however, the illness often takes a serious left turn, especially in cases that occur in the Americas. Patients may begin developing coughing and shortness of breath as the lungs start filling up with fluid. What started as "I feel like I caught a bug" can escalate real fast into a medical emergency that requires intensive care, which brings us to our next question.

Answer: Hantavirus pulmonary syndrome (HPS)

In the Americas, the hantavirus illness that gets reported most often is hantavirus pulmonary syndrome, usually shortened to HPS, because who has the time? It first gained notoriety in 1993 when a mysterious, often deadly, respiratory illness appeared in the Four Corners region of the United States, where Arizona, New Mexico, Colorado, and Utah meet. Doctors were stumped. Young and otherwise healthy people were developing flu-like symptoms that rapidly progressed to severe breathing problems as fluid filled their lungs.

Researchers traced the culprit to a hantavirus carried by deer mice. The virus was eventually named 'Sin Nombre virus', which is Spanish for 'no name virus'. The name stuck, proving that creativity is not a prerequisite in virology.

The innocent-looking deer mice themselves were perfectly healthy. They simply were doing what we all do (yes, you too, ladies). The bad news? When all that poop dries out and humans inhale contaminated dust, the virus can enter the body and cause HPS, which has a case fatality rate of around 30 to 40 percent. That's a statistical argument against cleaning the garage if there ever was one.

Answer: Negative-sense single-stranded RNA viruses

Hantaviruses belong to a group of viruses known as negative-sense single-stranded RNA viruses. Apparently, when molecular biologists aren't jokingly calling viruses 'no name virus', they're coming up with the ugliest, most esoteric nonsense you can imagine.

This term basically just describes how the virus stores its genetic instructions. Instead of DNA, hantaviruses carry their genome as RNA, which you can think of kinda sorta like a single strand of DNA instead of the famous double helix we all know and love.

But it's not just any RNA. Their RNA is in the "negative-sense" orientation.

What the heck does THAT mean? First a quick recap for those who hate this stuff. Viruses can't reproduce by themselves. They basically hijack cells in a host and trick the cell to make more copies of itself, so it can... well, infect other cells.

Now, negative sense orientation. You can think of it kind of like a virus arriving with a set of instructions written backwards. Before the virus can hijack the host cell, it needs to first flip the script into a readable format. Once that happens, the cell's machinery happily starts producing viral proteins and new copies of the genome, turning the cell into a tiny virus factory. Not great for the cell. Fantastic for the virus!

And that's all I have to say about negative-sense single-stranded RNA viruses.

Answer: Hantaan virus

Hantaan virus is the one, the original, the classic member of the hantavirus group which is carried primarily by the striped field mouse. The mouse itself looks fairly ordinary. Small, brown, quick on its feet. With a black stripe running down its back like a mohawk.

Nevertheless, it just happens to serve as the natural reservoir for this virus across large parts of East Asia and nearby regions. The rodents do not get sick from it, which should make us all suspicious of its motives. No, they just carry the virus and shed it in its excreta, which means humans usually get exposed by breathing in contaminated dust.

This is the virus that first caught the bespectacled eyes of science nerds during the Korean War in the early 1950s. Thousands of soldiers stationed near the Hantan River developed a mysterious illness that included fever, bleeding problems, and kidney failure. The exact cause remained a mystery until the 1970s, when South Korean scientist Ho Wang Lee finally isolated the virus from striped field mice. The virus was then named after that nearby river.

Answer: Hemorrhagic fever with renal syndrome

In Europe and Asia, the hantavirus illness that is most commonly reported is hemorrhagic fever with renal syndrome, usually abbreviated HFRS for obvious reasons. Unlike the American flavor, it affects the kidneys and the body's small blood vessels. Early symptoms resemble a bad flu. Fever, headaches, muscle pain. Then things can escalate. Patients may develop low blood pressure, bleeding problems, and kidney failure. Not cool.

Several hantaviruses cause HFRS, including Hantaan virus, Seoul virus, Dobrava-Belgrade virus, and Puumala virus, and I know not how to pronounce any of those. Each is associated with a specific rodent host, because viruses know the importance of loyalty.

The striped field mouse carries Hantaan virus in East Asia, bank voles in parts of Europe are linked to Puumala virus, and so on. These rodents are not exactly plotting against humanity (that we know of). They simply go about their normal rodent lives while shedding virus in the stuff that makes true gentlemen say, 'Oh, how common'. You know the drill by now: we get sick when we accidentally (or purposefully) inhale contaminated dust or come into contact with those materials.

Compared to hantavirus pulmonary syndrome in the Americas, HFRS has a wider range and far more recorded cases each year, particularly in China, Russia, and parts of Europe. However, the severity varies quite a bit depending on the virus strain. Puumala infections in northern Europe are often milder, while infections caused by Hantaan or Dobrava viruses can be much more serious.

Answer: Cool, moist environments

Hantaviruses are pretty delicate at first when they leave their rodent hosts, but certain conditions can help them hang around much longer than you'd expect. Cool, moist environments tend to preserve the virus best.

Lower temperatures slow down the processes that break viruses apart, and moisture prevents the rapid degradation that happens when organic material dries quickly. In the right conditions, hantaviruses can remain infectious in the environment for several days. This keeps the virus viable long enough to dry out still intact and make your month miserable.

Answer: Deer mouse

The main culprit for hosting the Sin Nombre virus in North America is the deer mouse. I checked. It doesn't look like a deer at all.

Instead, it's a small and wide-eyed rodent that looks harmless enough, with big ears and even a neat little white belly that you just want to rub. Unfortunately, it also serves as the main carrier for the virus responsible for many cases of HPS in the United States and Canada. The mice themselves don't get sick. No, with their cute little ears and big Disney eyes and their rubbable belly, they lie in wait, hoping for an opportunity to poop in your shed and make you very sick.

The connection between deer mice and Sin Nombre virus became clear during the famous 1993 hantavirus outbreak in the Four Corners region of the southwestern United States. Scientists doing their scientist thing trapped local rodents and tested them, eventually discovering that a high number of deer mice were carrying the virus. That discovery solved the mystery behind the sudden cluster of severe respiratory illnesses in the area that had doctors scratching their heads.

And of course, deer mice are extremely common across North America and are quite happy in a wide variety of environments. The tiny adorable rodent just goes about its tiny adorable rodent business, completely unaware (according to the mouse, anyway) that it's the villain of the story.

Answer: Bank vole

The main host for the Puumala virus in northern Europe is the bank vole, which is not nearly as cute as the deer mouse, for whatever that's worth. This small woodland critter calls Scandinavia and much of northern and central Europe its home and, like most hantavirus hosts, the bank vole carries the virus with no symptoms. It poops, the poop dries out, people inhale the dust, people get sick.

Puumala virus causes a relatively milder form of hemorrhagic fever with renal syndrome, sometimes referred to as 'nephropathia epidemica', which sounds more serious than it is. Most cases are not fatal, though the illness still isn't pleasant. Patients often develop fever, headaches, abdominal pain, and temporary kidney problems.

Hospitalization is fairly common, but most people recover fully after a couple of weeks of feeling really quite miserable.