Hello! And, no, you're not hallucinating. This is Michael Aranda sitting in for Hank Green. Standing, really. You're in the right place, so welcome back to SciShow News.

If you do feel like you're seeing things, it could be because you're in the grip of the flu, which has struck the United States in the past couple of weeks like Super danged Smash Brothers.

According to the U.S. Centers for Disease Control and Prevention, more than twice as many cases have been reported than at the peak of last year's flu season, and we're just getting started.

So, why is this bout of influenza different? What virus is causing it? And is it all Australia's fault? And what in the name of Dr. Gregory House do I do now? Just relax and stay hydrated while we answer some of your most F-A'd Q's of the new flu season.

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Flu FAQ number one: Is this an epidemic? Yes, actually, it is, but try to keep your head together. When everyone around you is hacking and having fever dreams, it probably feels like an epidemic, but according to the U.S. government, an epidemic is official when the proportion of deaths caused by influenza and pneumonia, as reported by 122 cities across the country, exceeds 7.2% of all reported deaths. And for the first week of January, it reached 7.3%.

But don't freak out, because the truth is we hit this threshold almost every year and we usually stay at this level for months, anywhere from 10 to 18 weeks. So, pace yourself, because this party is just getting started.

Epidemics, by the way, are a whole different box of Kleenex than pandemics. Pandemics are global outbreaks that are measured by how far and how quickly diseases spread as opposed to how many deaths they cause.

Number two: So, what's it called? Is this swine flu again or what?

Swine flu, which you may remember as H1N1, is so 2009. What we're dealing with this time around is a different little bastard called H3N2 A.

As you regular viewers may recall, there are three main types of flu virus, which scientists call A, B, and C. "A" is the kind humans get most often, and from a "feeling crappy" perspective, it's the worst of them.

But there are tons of A-type viruses because they mutate really quickly all the time, so we categorize them by the changes these mutations cause to the proteins in them. The proteins are the H's and the N's you keep hearing about.

Hemagglutinin is a protein that follows a virus to stick to the inside of a cell while it's infecting you. Neuraminidase, meanwhile, is a protein that helps viruses that are created in the host cell to be released and infect even more cells, which is...great.

So, the virus we call H1N1 was the first to be categorized this way, and it includes the hella-deadly Spanish flu that wiped out 100 million people in 1917 and 1918. It also made for a particularly good episode of "Downton Abbey."

But this year's arch villain, H3N2, has a different story. It was first identified in 1968, when it caused a pandemic that started in Hong Kong, infecting half a million people there and then spreading to the United States, where it killed 33,800 people.

As pandemics go, 1968's wasn't particularly horrible, but since then, H3N2 has earned a record of causing higher rates of hospitalization and death than other strains.

So, even though H1N1 has gotten the most of the media hype in recent years -- along with the so-called bird flu, or H5N1 -- H3N2 has become the dominant kind of seasonal flu.

Number three: So, why am I just hearing about H3N2 now?

Well, in the United States, at least, it's been laying low for a few years. H3N2's last really major showing was in 2002 and 2003, where it accounted for 95% of reported flu cases. It also figured prominently in 2007 and 2008, when about 3/4 of the flu reports were traced back to it.

But this past summer, H3N2 ran roughshod over Australia and New Zealand, and now what's known as its Victoria strain has hit the U.S.

However, because prevention in the U.S. has been focused on other strains in recent years, most people are now under-protected for H3N2, which is why we have this particular epidemic on our hands.

(03:38) See this map here? Yellow indicates where flu outbreaks are strictly local. Brown means it's widespread. Yep.

This Aussie-American dynamic is complicated by the fact that the Southern Hemisphere and the Northern Hemisphere experience winter -- and therefore flu seasons -- at opposite times. It starts down in the South around April and runs until September, when it then starts in the Northern Hemisphere and goes until March, and then it begins all over again. The world is just one big flu season.

And because the two hemispheres have different flu seasons, they actually get different sets of vaccines. Every year, the World Health Organization recommends which strains each hemisphere should get vaccinated against, based largely on what happened in the other hemisphere.

So, while people in the Northern Hemisphere are now getting vaccinated for the Victoria strain of the virus that was discovered in 2011, just a few months ago Aussies, Kiwis, Africans, and South Americans were getting dosed against a different, older strain called Perth 2009.

Number four: Well, what do I do now?

First, get a vaccination if you haven't already. It's not too late, and it's particularly important for children, people over 65, and anyone with chronic conditions like asthma or immune deficiency.

Second, if you're sick, for the love of Pete, stay home. No one wants your stank, germy breath being breathed on them, and it's not the end of the world if you miss a couple days of class or work.

And finally, vaccines get the most media attention, but it's important to remember that antiviral drugs are an option, too, especially if you're in one of those at-risk groups. They won't cure you, but they'll help keep complications at bay and can shorten the time that you have symptoms.

So, remember, even though viruses hate you, science has your back.

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