The single-cell organism that carries African sleeping sickness has a mating ritual.
Your fifth grade science teacher probably showed you a slideshow in which all single-cell organisms reproduces via some category of fissile cell division. AND WE WENT ALONG WITH IT. Mostly it was because we were kids and elementary school science teachers sometimes save their nuance for the faculty break room gossip scene. Anywhom, it's been discovered that some uni-cell organism are choosing intercourse over breaking themselves off.
Per the University of Bristol (via World-Science.net), the Trypanosomes (the buggers responsible for African sleeping sickness) are making babies like grandma and grandpa did it. A) These blood-transmitted microbes are swapping DNA through some crude (heh) manner of intercourse. And B) these tiny buggers aren't doing it like they were on spring break in Panama City; they're actually courting one another.
According to the study, "The microscopic beasts were seen twirling and gyrating together before joining up into one hybrid cell. Their flagella or "tails" became intertwined in the process."
OK, that's EXACTLY like Panama City spring break but it's pretty advanced for things without nervous systems. The worrisome part is why the microbes are doing it. Per the study's architect, Wendy Gibson, it's for the same reason as us. Nope, not wine coolers and loneliness: bio-diversity.
These blood-borne organisms, which deliver horrible disease transmitted via the tsetse fly, are swapping fluids to become stronger. Like other horrific things, the new Gonorrhea for instance, these Trypanosomes are Darwin-ing us to death by becoming even more resistant to medication. The strong are passing on the "good" genes and the weak are dying in some muddy hole.
Sorry to give you one more thing to worry about. Hopefully scientists will come up with an anti-microbe boner spray at least as effective as screaming baby or vanilla-scented candle.