Add this to the list of ways scientists keep taking the fun out of sex. Although it's a far cry from chlamydia, there is a type of food poisoning that is sexually transmitted. This dastardly disease is known as ciguatera fish poisoning, and is initially contracted when a person eats a seafood dinner that, unbeknownst to them, includes a side of fish toxins. This happens when a single-celled protozoan cozies up to algae found on tropical reefs, creating a ciguatoxin. Various marine life consume the algae, other fishes munch on them and so on until the biggest and baddest fish in the sea (like grouper and red snapper) have eaten so many that the toxin accumulates in their systems. When said fish is hooked and eaten, it passes its secret treasure along to whoever's eating it. Then, when he goes home for a little nookie, the poison actually travels via semen to the sexual partner [source: Doucleff]. Sounds like yet another marketing opportunity for condom companies, to me!
Symptoms of ciguatera fish poisoning include gastrointestinal upset, painful sex and cardiovascular issues [source: Friedman, et al.]. Many people even report neurological issues, such as opposite reactions to temperature, with cold things feeling hot, and vice versa. Currently incurable, treatment is sometimes effective, but has to be administered immediately after onset otherwise the patient is left to tough it out for weeks, or even months. Although it might seem totally off the wall to those of us in temperate climates, it's actually fairly common in tropical regions. The booming fish import trade, however, is threatening to change all of that, bringing the disease further north and inland [source: Doucleff].
So how do you avoid ciguatera fish poisoning? Be aware of warnings when in regions experiencing outbreaks or avoid consuming larger types of fish altogether. There literally are many fish in the sea, so there's no sense in eating one that'll make you so very sick!