Ahhh fall. There’s nothing quite like it: the earthy smell of plants going into dormancy, the vivid and spectacular color show of changing leaves, the cool, crisp bite of the autumn breeze…

Oh, and of course, gonorrhea.

Yes, ‘tis the season, ladies and gentlemen. Believe it or not, infectious diseases are almost as seasonal as food and fashion – they come and they go, spike and fall by the changing months, as temperatures, moisture levels, and host behaviors change.

And in fall, for reasons still being researched, gonorrhea tends to snowball.

“It’s not that we’re vulnerable at a particular part of year and then healthy at another,” explained Micaela Martinez, an infectious disease ecologist at Columbia University’s Mailman School of Public Health, in an interview with NOVA. “We’re restructuring throughout the year. And the identity of the thing we’re vulnerable to changes with the seasons.”

Martinez recently published a paper detailing this phenomenon. Originally, she set out to track the seasonality of short-term infections like chickenpox and the flu but stumbled onto something much more suggestive. She found that, not only were there cyclical, seasonal patterns for those acute short-term infections, but also for chronic, long-term, infections like gonorrhea, leprosy and genital herpes.

“It’s an even more widespread phenomenon than we thought,” Martinez says.

According to the calendar she published, gonorrhea tends to spike in autumn and winter – typically because of an uptick of summer-sex. As does Hep B, and Yellow fever.

Come wintertime, according to Martinez’ calendar, people can expect outbreaks of influenza, avian flu, and respiratory syncytial virus (RSV). When the snow melts away and life starts to reemerge in springtime, so too will genetial herpes, Hep C, dengue fever, cryptosporidium and diphtheria. And then, summertime, that swealtering hell-season, is sure to usher in outbreaks of cholera, shingles, smallpox, syphilis and typhoid fever.

Obviously, your geographical location on Earth has a lot to do with what infectious diseases might be circulating around you at any one point of time throughout the year. But generally, this is the spread.

“This isn’t just about transmission—seasonality is also in the human body itself,” says Martinez. “There’s something happening in our bodies we don’t quite understand yet. Seasonality in infectious disease is just an enticing little piece of the puzzle.”

So, there’s a lot still to be gleaned from this cycle of infection. A lot still to be researched. But, what is certain and known and proven beyond a shadow of a doubt, is that fall is the season of color, the season of cool, fresh air, pumpkins, root vegetables, witches, ghosts, ghouls, and, of course, gonorrhea.

Happy fall, everyone.