How can a parasite that feeds on sex take over a human biochemically?

Question

I wanted to take a different direction with the succubi/incubi mythos and make it more grounded by turning it into a disease for a horror setting. A fungus exists today which can take over the body of ants called the O. unilateralis, and decided to model a parasite in this setting off this creature. Although acting on instinct at first, it eventually grows more intelligent the further It spreads. It feeds on semen, and transmits itself by acting in a similar way to an STD by invading a host body and using it to infect other bodies. This parasite would make the host body infertile, and compel it towards spreading the infection to others.

Hypothetical scenario: This parasite originally infects a female host, taking up residence in the genital area. It slowly subsumes the host's mind, compelling her towards sexual activity with multiple males. The parasite helps this process by heightening her attraction to others, perhaps through hormones or altering features. It uses some chemical to strengthen orgasm, encouraging as much ejaculation as possible for it to feed. During climax, the parasite passes on a piece of itself into the unsuspecting male, turning them into a carrier. Over time, it subsumes their mind and compels them to use any and all methods to have intercourse with as many people as possible as fast as possible, passing on the infection.

Using this method, how can a parasite take over a person biochemically to successfully transmit itself into enough people to create a hivemind? And how can it go unnoticed?

Answer 1

I'm going to leave out a lot of detail in the ability to create a hive mind, as in theory lots of individuals performing the same task in order to benefit the the colony is what Hive Minds are all about, and are generally not the typical Modus-Operandi of a parasite. parasites live off their host which negatively effects the host. hive mind animals don't really do this, i'm sure there are some that do, but as a whole they tend not to.

Parasite Targets

Your better option is is to actually not infect males in the same way, the reason i say this is that "any and all methods to have intercourse" means they'll be a lot of rape, and even if the infected victim is then overcome by the parasite and doesn't press charges, there'll still be witnesses, and if suddenly a small town went from 1 or 2 cases of rape a year, to several hundred, then it will be looked at very carefully including the biochemistry of the assailants, also rape victims (assuming the parasite doesn't take control in less than an hour), would get checked over by paramedics and doctors in hospital and cultures taken to see if the victim contracted an infect as part of the process (Standard UK procedure at least) meaning it would likely be discovered in due course of those results.

Seeing as its not often that rape on men is anywhere near as reported, and in theory harder to do as the female assailant will want conventional intercourse, means that there are less "victims" in the conventionally non parasitical sense therefore less people looking into it.

Target Environment

Perhaps the parasite could release chemicals that effect the behavior of the host to encourage it into areas where promiscuity is more likely, perhaps it craves dark areas with bright flashing light, there are many case of illnesses that make people light phobic or dark phobic, so a strange combination of both might encourage the infected into "clubbing" areas, where the free use of alcohol and drugs makes intercourse more likely.

Perhaps the parasite cause the body to burn more calories, this would make the host hotter and therefore more likely to prefer being less dressed/completely undressed even in public, this may assist the virus in other ways, it would not want 2 infected to engage with each other in the bedroom/toilet stall as that would waste efforts and not increase transmission, so perhaps the higher heat could be detected by the parasite and turn the host away from each other

Perhaps the host body has increased muscle tension, seems insignificant at first, but if a woman were to have several partners in an evening, then being... tighter... would make the process quicker once activities began. also she would probably need to produce more lubricant, which in itself could assist in the transmission of the virus.

it also needs to produce a lot of feel good hormones in the host, (unless it can completely control the host) as humans often, when not feeling well, avoid others and call in sick or see a doctor, so to go unnoticed, it must make the host feel really good so they are in a good mood, less likely to call in sick less likely to go see the doctor.

Then of course there is the possibility of the parasite releasing pheromones to attract more mates.

Final thought

You story sounds similar to the Sixth Extinction by Glen Johnson, might be worth reading that series as it covers many similar notes just without the intercourse.

Answer 2

Okay, well, there's a few things here I'm not really sure about.

For one, parasites don't really have a sense of 'instinct' since they aren't sentient or sapient. You can't exactly call them intelligent, although famously dangerous viruses like ebola or malaria take use of very skilled tactics to overrun their host body.

The fact that the parasite feeds on semen is both unnecessary and useless. Not only would it ensure that the parasite can only spread exponentially in the male gender, but real parasites don't really need to 'eat', per se. It could probably remain realistic without that part altogether.

Altering features wouldn't really be easy to do for a parasite. For research on diseases that do exactly that, you can refer to elephantasis on Wikipedia, which affects both males and females in the genital areas (it's actually kinda disgusting how large they get). You should probably stick with the parasite altering hormone amounts in the body, since that sounds much more plausible.

Finally, with the way you describe it, the parasite would probably only go unnoticed for but a few days before news stories start covering the unusual amounts of sex in the population. The fact that it makes humans infertile, though, would kill both the parasite and humanity pretty darn quickly.