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2018 should be a big year for us disease buffs. It is the 100th anniversary of the 1918 flu epidemic, perhaps humanity’s worst ever disease disaster. And it might be the year we send another disease to join smallpox in the dustbin of history – with luck, maybe even two.

Disease has always ranked with war and famine as humanity’s chief sources of death and misery. But apart from a few things like cancer, many people assume that wealthier countries have pretty much licked disease and famine.

Sadly, a bit more pessimism seems to be in order. No sooner do we beat back a smallpox or a scarlet fever (which staged a comeback in 2017), than another germ emerges from the roiling, global pathogenic gene pool to replace it. What is a disease buff in search of happy holidays to do?

Guinea worm horror

Well, consider the guinea worm. This does require a strong stomach. You drink water containing its larvae, they grow and migrate inside you for a year. Then a metre-long worm sticks its ovipositor through your skin – if you’re lucky, on an arm or leg – causing enormous pain that you relieve by immersing the area in… a body of water. A squirt of eggs and the cycle begins again.

The only treatment is to gradually wrap the emerging worm around a twig to extract it. Hence the stick and snake that has symbolised medicine for millennia.

This horror is prevented by modern water systems, but it still afflicted 3.5 million people in 21 countries in Asia and Africa in 1986. This year, there were, , 26 cases in only two countries.

All this with no medicines, no vaccines – just dedicated, mostly local, staff watching for cases, keeping them out of water sources, digging wells, spraying larvicides. War ravages South Sudan, but it had no reported cases in 2017. At present, only Ethiopia and Chad still do.

Chad was a surprise, though. In 2010, it had been worm-free for a decade. Then someone reinfected the Chari river. It turned out that fish ate the larvae, caught fish were cleaned onshore, dogs ate the fish guts – and got worms, which reinfected people. No one knew dogs could even get guinea worm. Now dogs with worms are kept away from water, people bury fish guts and, for the first time, last year infections fell in both people and dogs.

Polio fights back

The re-emergence is why us disease buffs are pessimists: you never know when a disease will totally surprise you.

Consider polio, , compared with 34 in 2016, in only two of the three countries that still harbour the virus. More good news.

But we got there using a vaccine containing live, weakened polio virus. This was cheap and effective, but, as ¿ìè¶ÌÊÓƵ revealed in 2000, it was able to revert and cause polio, a problem as eradication reaches its endgame. We had 84 such cases in 2017. See what I mean? Surprises.

Quietly circulating

In September 1918, a flu of unprecedented ferocity struck the world. As many as five per cent of the global population died.

But it wasn’t sudden. Epidemiologists have recently discovered that the 1918 virus, a bird flu that adapted to transmit between humans, was already quietly circulating about this time of year a century ago.

It is déjà vu already: right now is circulating in China with the genes to spread between mammals, just like 1918 except way more lethal. We don’t have good enough vaccines. We do have antibiotics for the bacterial pneumonia that can follow flu and killed many in 1918.

Oh, wait. Antibiotics that bacteria increasingly resist. And that resistance could skyrocket amid the massive demand for antibiotics during a flu pandemic. So maybe not.

Remembering 1918

There will be commemorations of the 1918 epidemic in 2018. Canada will have a . US health agencies plan a . There will be a and exhibition in London, and the UK’s Wellcome Trust is planning  a project called Contagious Cities, with exhibitions and art, in Geneva, New York and Hong Kong.

I hope we don’t commemorate the great flu of 1918 with an even bigger one in 2018. But we disease buffs are used to surprises. Meanwhile, pass the eggnog.