The flu tends to lurk around on an annual basis. However, the numbers of tests and diagnoses for flu has increased massively this winter according to others that I work with in the hospital microbiology lab – and it’s not just a local problem. This winter season, the outbreak of flu seems to have been quite a lot worse for the whole of the northern hemisphere. And it’s not over yet. If the past winter season in the southern hemisphere is anything to go by, we’re going to be fighting this virus for a while longer. I’ve tried to cover the basics of the flu topic, but also check out this video explaining the flu virus pretty damn effectively!
WHAT ACTUALLY IS THE FLU?
The flu is an acute infection of the respiratory tract caused by the influenza virus, of which there are three strains; A, B, and C. All three of these strains are similarly structured – a viral RNA genome at the centre, encased by proteins for protection – but depending on which proteins these are determines which strain the virus is. The A strain is also broken down even further into sub-types, depending on two of the surface proteins (haemagglutinin (H) and neuraminidase (N))… and then broken down EVEN FURTHER as there lots of different H and N combinations.
The C strain tends to be more harmless, only really producing mild infection, with the A and B strains causing more problems and even pandemics. For example, here are the notable A strain outbreaks from the past century:
- Spanish flu (1918) – 50 to 100 million dead due to the H1N1 strain
- Asian flu (1957) – outbreak of the H2N2 strain shortly after the strain was first identified
- Hong Kong flu (1968) – H3N2
- Russian flu (1977) – H1N1
- Bird flu virus in Hong Kong (1997) – H5N1 strain
- Swine flu outbreak (2009) – H1N1 mutation, with a recording 3-400, 000 fatalities
- Avian flu (2013) crossed over to human populations (H7N9)
As a result of this viral infection we can get an array of symptoms! These symptoms vary from the most common sore throat and fever, to the more severe cases which cause serious illness or even death (due to pneumonia and other complicating factors).
WHY DOES FLU BECOME SO COMMON IN WINTER?
Flu is a disease which prefers cool, dry environmental conditions. Because of this the disease continuously circulates south east Asia and tropical regions, where conditions remain like this pretty consistently. But, when it hits winter in other, more temperate areas, flu has the chance to spread and expand in these seasonally cool and dry places.
HOW IS THE FLU SPREAD?
The disease very effectively transfers from person to person through exhaled water droplets, whether it be through direct inhalation of these infected droplets (e.g. breathing in someone’s sneeze… ew), or coming into contact with contaminated surfaces (and then touching your face and spreading the germs).
HOW DOES IT KEEP COMING BACK THOUGH?
Unfortunately, flu is also extremely good at fighting its way past our immune systems (no matter how strong) by going incognito of sorts. We cannot be immune to catching the flu – unlike measles or chickenpox – as having the disease previously does not stop you from catching the horrendous thing again.
This is because the virus, or more accurately seven different points on the sizeable proteins on the virus’s surface, is always mutating. In most cases, these mutations are pretty small – and so only vary a little bit from last years batch of the flu. When you catch this version you will likely be partially immune to the virus, but not completely. However, the virus is constantly changing, so after a while there will have been so many mutations on the virus surface that our bodies’ self-defence system (antibodies) wouldn’t even recognise the incoming flu as the one we’d caught before. Sneaky.
Even worse, sometimes a new A strain emerges (one of the 18 H and 11 N protein combinations) out of nowhere, which is completely mutated from anything our immune systems have seen before – we don’t stand a chance! This is when a more severe flu outbreak, epidemic or pandemic occurs.
And that’s potentially what could be happening now in the UK and US. The more mutated H3N2 strain has already spread across the whole of Australia, causing double the number of hospitalising flu outbreaks in the country. Severe cases of this strain have been growing in the states, and will inevitably make it to us, if it hasn’t already. So, just be prepared as much as you can! The World Health Organisation recommends the vaccine composition for this particular flu season (but get them each year if you can), which I already have. …And take precautions! Mainly, if you think you have the flu try to minimise spreading it by not going into work, school or uni, and definitely encourage others to do the same.
Well, now it’s time to try and dodge anyone who sneezes near me for the remaining flu season! Good luck!
If you want to find out more about influenza or any other kind of disease, infection or virus then check out the World Health Organisation (WHO) or Centers for Disease Control and Prevention (CDC) websites.
Let us know if you have any questions about the flu, or about writing your own blog about something similar!