There’s a joke in our house that never fails to get a laugh…Why did the toilet paper roll down the hill? Because it wanted to get to the bottom. “Bottom! Mum said bottom!”

So I trust that writing the word poo started to form a slight smile on your face. Let me see if I can make your face change a little more.

Your poo is made up of bugs. Dead bugs. Bacteria, viruses, fungi, and archaea (very similar to bacteria but different enough for scientists to give them another name). Some of these bugs played a helpful role for you in your body. They helped to digest some of the food that your body could not in a process known as fermentation. Fermentation is probably better known by some for the wonderful work it can do in alcohol, but a similar process is happening at the end of your gut.

You see, your body has always relied on bugs to help complete the job of digestion. In the process of bugs fermenting food that you haven’t been able to digest, by-products are release. These by-products work to keep you healthy (Stephen et al. Nutrition research reviews 2017:1-42).

For instance, some of the bacteria in your gut will ferment leftover food particles and release compounds that stabilise your blood sugars and improve your immunity (Adv Nutr. 2016 Jan; 7(1): 1–4). Other bugs do their job and in the process are thought to protect us from certain cancers, inflammation and allergies (Macfarlane. J Clin Gastroenterol, 2011 Nov; 45 Suppl:S120-7).

That is why health professionals will always recommend high fibre foods as the more fibre you eat, the more you are feeding these bugs and reaping the benefits. Fibre is the main type of food that these bugs eat because it is the stuff you can’t digest yourself so it travels through your gut to feed those bugs at the end.

There is a little more to your poo than bugs – there are also dead gut cells and water (heaps of it). But it is one more thing in your poo that may prove to be extraordinarily helpful during this difficult time. Something that will help us monitor how we are progressing with Covid-19 control and that is the appearance of the virus SARS-CoV-2 (the virus responsible for what we commonly refer to as Covid-19) in the poo of infected people.

Clever scientists in Brisbane, Australia have been able to detect the virus SARS-CoV-2 in untreated wastewater for the first time (Sci Total Environ. 2020 Aug 1; 728: 138764). This follows studies in Monte Carlo and USA that were able to then use complex calculations to estimate how many people this meant were likely to be infected with Covid-19 in the local area from which the wastewater was collected. Reports indicate we are not quite there in Australia but the possibility of monitoring Covid-19 cases at a population level seems to be close.


It is a way of checking whether the numbers we see through testing for the Covid-19 virus are accurate. Does an area with no positive cases also have no signs of Covid-19 in the wastewater?


So the next time you flush the toilet without so much as a glance at the wonderful creation below, perhaps a little word of thanks wouldn’t go astray.