You have a fever, runny nose, and can't get out of bed. It must be the flu, right? Not necessarily.

In the 16th Century, over the course of five years, almost 80% of the Aztec population were wiped out due to an unknown disease that burnt through their villages, causing high fevers, bleeding from the mouth, nose and eyes and eventually lead to death. Without understanding the epidemic, the Aztecs named the phenomenon 'cocoliztli', their native word for 'pestilence'.

Scientists have pondered the potential cause of the cocoliztli epidemic for years, but only recently has new research uncovered what may have caused it.

Here's a cool thing. When you're sick, or allergic, or something flies up your nose, and you spasm and expel mucus, it's polite for anyone around you, including complete strangers, to call attention to it. In English-speaking countries they say "Bless you," in most of Europe they say "Health."

In almost every culture, the polite response is "Thank you." As in "Thank you for calling attention to my embarrassing bodily function." As in "Thank you for making me thank you while I'm probably still dealing with how something inside me is now outside me." As in, "Thank you for alerting me that for the next three months, I'll be having impromptu two-line conversations with strangers, because my body thinks flowers want to kill it."

You're on your hands and knees praying to the porcelain god, and between each of your wretched retches you curse the name of that restaurant you ate at a few hours earlier. But that place is probably not the culprit, even if you're seeing that meal in reverse.

Despite thousands of years of pant-crapping history, there's a surprising amount we don't know about diarrhoea. There's a couple of ways we've figured out how to treat the symptom. But a lot of scientists' understanding of diarrhoea -- from illnesses such as traveller's diarrhoea -- is more based on intuition than data.

Video: If you want to get rid of a cough, it's natural to reach for something labelled "cough medicine". But the ingredients in cough medicines probably don't work as well as you think they do. This video explains the sad situation.

I'm at home rocking the summer cold from hell. Meanwhile, my partner is checking out a bunch of cool tech at CES in Vegas.

Suffice to say, I'm feeling a bit sorry for myself.

We're pretty good at being caretakers when we're in the country though. We've both played nurse while the other was excreting a whole manner of unholy bodily fluids.

Hospitals across Melbourne were put on emergency alert on Monday night as thousands of people called ambulance services, reporting breathing difficulties and other severe symptoms. Emergency rooms were so strained that day units were opened to handle the overflow. It was a severe outbreak of the phenomenon called "thunderstorm asthma" -- but how does an emergency like this actually happen?

Imagine this: You’re an elite athlete, and you’ve spent years working towards your shot at Olympic glory. You’ve trained hard, been totally dedicated to your sport and now, here you are in Rio, getting ready for the pinnacle of your sporting career. It’s your time to shine. But suddenly, without warning, you are hit with stomach cramps. It’s not nerves – it’s more intense than that. Vomiting and diarrhoea kick in. Slowly and devastatingly, your chances of success go down the toilet.