Health experts have long warned about the threat of antibiotic resistance, and the evidence for that has been mounting ever since the rise of superbugs.
But it’s now clear that resistance can’t be pinned on just any bacterium.
Instead, the main culprit is a specific strain of bacteria that can be isolated and spread by the flu virus.
That means we now have a more accurate picture of how the virus spreads, and a better idea of how to treat it.
In the coming weeks, the Centers for Disease Control and Prevention (CDC) and other federal agencies will release guidelines for diagnosing flu infections, as well as a roadmap for how to deal with the infection.
So let’s take a closer look at what we know about the flu pandemic and how we should treat it if you’re sick.
The history of the flu There’s an ancient history of flu pandemics, and scientists say that there are several different versions of the pandemic that are connected to one another.
The 1918 pandemic killed an estimated 7 million people in the U.S. It was preceded by the 1918 influenza pandemic, which killed roughly 6 million people and killed about 1.2 million more worldwide.
In both cases, the first major pandemic was accompanied by a series of minor epidemics that had a smaller impact.
That’s the reason why the 1918 pandemias were so devastating: The flu could easily have wiped out large swaths of the population, and researchers were sure that a second pandemic would be more easily contained.
So the CDC set out to determine what happened to all of those small outbreaks, and found that they all began in one place: the U-shaped area between the U and E curves.
This is where most people have the flu, but there are some who are at higher risk of getting it.
People in these two groups were especially likely to have been infected with the 1918 virus, so they were likely to become infected with other strains of the 1918 flu.
By comparison, the CDC found that there was no such correlation between the number of people who contracted the 1918-1919 flu and their susceptibility to other strains.
That meant that people with higher levels of immunity were more likely to survive the pandemic than people with lower levels of protection.
The next big flu pandemaker In the 1920s, researchers discovered that the 1918 strains of influenza had a strong genetic similarity to the ones that have become known as H1N1, which are commonly known as bird flu.
Bird flu viruses, which usually start out small and spread rapidly, tend to have an enormous number of copies of their genetic code in the same region of the genome, so their genetic composition is often similar to that of the influenza viruses.
As more people get infected with a H1-type virus, the number and type of copies in that region of their genome changes, and that genetic change can make them more resistant to the pandemaker.
Scientists have long known that H1 viruses, or bird flu, have a number of unique features, but it wasn’t clear how those features got transmitted from one person to another.
In 1918, for instance, the influenza strains that were spreading rapidly had a very high number of genetic similarities with the H1 flu, while the H2 viruses had only a few of them.
The difference was that the H5 flu strains had a few more genetic similarities to the H6 flu.
Researchers began to suspect that the genetic differences that gave birds the advantage of having such a large number of variants in the 1918 H1 virus were also present in the H3 flu, which had the lowest number of such variants.
This meant that birds with high levels of resistance to the 1918 bird flu might be more susceptible to the other H1 and H2 strains.
But that wasn’t the case, and bird flu didn’t spread very well into the 1930s, even though the H4 virus did.
That was the last pandemic of the 1930-1939 flu, and it left us with a much more manageable flu situation.
For a time, scientists thought the H-series of flu was simply a variation of the bird flu that didn’t have much effect.
But in the early 1960s, scientists noticed that it had a lot of similarities to other viruses.
In 1962, scientists discovered that there were more genetic differences between H1, H2, and H4 viruses than between the H7 and H8 viruses, and these differences were much more important than the genetic similarities between the birds.
When researchers tried to replicate the 1918 viruses to see if they could replicate to the degree that birds had, they found that the bird viruses didn’t produce much of a difference at all.
And when scientists replicated the 1918 versions of H3, H4, and other bird flu viruses to look for differences, they discovered that they did produce some.
But these differences did not make the virus much more effective.
The H5 and H6 viruses did produce slightly higher levels at a time when the 1918