The answer is in the toilet

As the seat-belt light stubbornly refuses to go out, and the three G&Ts sunk even before the pilot levelled out begin to nip at the bladder, a visit to the diminutive toilet cubby is rapidly becoming a priority.

With excuses and apologetic glances made, balance tested to its elastic limit and door locking mechanisms negotiated, the routine business of nature can begin. A dart of relief, and then the brusque exhale of the flush mechanism. It is, we suggest, the most recognisable modern experience of air travel.

What happens to the ravenously ingested proceeds of the exchange has, to us at least, remained a mystery. We frankly dwell on it as little as we can. (Those childish rumours of frozen spears of urine falling to earth after a five-mile high ejection can’t be true…can they?)

But what if this most humdrum of airbourne activities was in fact part of an experiment – one so important it might actually save lives?

It is estimated that across the globe infectious disease accounts for 22% of all deaths. Over a fifth of all humans that meet their end do so due to microbes…microbes that have us outgunned and outnumbered. Part of the reason for this is that the advent of cheap modern air travel has allowed these deadly stowaways to hitch a ride to populations they may never have otherwise come into contact with. A juicy smorgasbord of human fodder is now open to them in ways impossible before the mass transit of people.

But there is a way to fight back. To understand how they move with us through these atmospheric superhighways is to forearm ourselves. Now, a team from the National Food Institute based at Technical University of Denmark have found a way they think we could do this. And it aint pretty.

It all hinges on – as we are sure you have guessed – the aforementioned ‘ingested proceeds’ of the toilet cubby. The team think analysis and genome sequencing of disease-causing microorganisms and antimicrobial resistant bacteria in toilet waste from international aircraft could be a first step towards the global surveillance of infectious diseases. And if we can understand how these diseases are transmitted between countries we can put in place better controls in the case of an outbreak. No mean feat.

Current international disease surveillance is mainly based on reports made by doctors after treatment of infected patients. As a consequence, microorganisms have time to spread and infect large swathes of a population before they are even detected. It’s not that they, so to speak, fly under the radar – there is no radar.

To test their idea they analysed toilet waste from 18 aircraft that arrived at Copenhagen Airport from nine destinations in South and North Asia as well as North America. 18! That, as they say, is a load of crap. The waste was analysed for all known antimicrobial resistance genes as well as a number of disease-causing microorganisms – and they could indeed find geographical differences. There was a greater variation in the resistance genes in the samples from South Asia, North Asia and all the samples from Asia combined compared with samples from North America.

So, they have here the makings of a successful – if rather gruesomely contrived – system of observation. As such, the next time you find yourself at 30,000 feet engaged in cramped excretion, allow yourself a moment of self-congratulation as you recognise your ‘donation’ is, in fact, part of a vital disease surveillance effort.