Khan (Ricardo Montalban), professional Ceti Eel handler.
Planning a vacation? Let me urge you to be an Informed Tourist and educate yourself about the types of parasites travelers to foreign planets may encounter. Picking up a brochure from the Federation of Planets' Health Department can help you avoid annoying diarrheal disease or parasitic mind control.
Vulcans and humans alike are subject to infestation of Ceti Eel larvae. Although this infestation is rare, emergence of the larva from under the armored scale of the reptile-like Eel adult, and subsequent migration to a human host has been known to occur.
If you encounter a Ceti Eel while on vacation, do not attempt to feed or touch it. Eels have been known to bite.
The larva enters the cranium via the auditory canal (ear hole), penetrating through bone and soft tissues alike to “wrap itself around the cerebral cortex.”
Eel entering auditory canal of non-consenting study subject. Eel size, approximately 3.5 cm.
Pathways utilized by the Ceti Eel.
How can an organism, only a few centimeters in length, wrap itself around a humanoid cerebral cortex? I have yet to find published research describing this phenomenon. Ceti Eel larvae are only a few centimeters in length when they enter the ear and (occasionally) exit it, with no measurable change in size or mass.
Diagram of cerebral cortex. It's big.
However, once ensconced around the cerebral cortex, the larval Eel can control the behavior of its host, compelling him to perform activities he (or she) would not otherwise engage in. The effect of the Ceti Eel on behavior is somewhat similar to the way in which the protozoa Toxoplasma gondii alters the behavior of the rodent it infects.
Chekov (Walter Koenig) doesn't want to help Khan. The Eel makes him behave like a rat on Toxo!
A MOMENT FOR EARTHLY MIND CONTROL
Just as Chekov wants to avoid Khan, rodents want to avoid cats. But rats infected by Toxplasma gondii demonstrate a distinct affinity to cat urine(1)! It is hypothesized that the protozoan influences rat behavior, for this particular parasite needs the rat to be eaten by the cat in order to complete its life cycle.
Mmm... what a lovely fragrance you have! Too bad this rat is under parasitic mind control!
In order to reduce your chances of Toxoplasma gondii infection(2) avoid eating or huffing cat poop, and don't vacation in France (or maybe you could just avoid French cats that eat a lot of raw game.)
BUT BACK TO THE EELS!
How does one detect Eel infestation? Signs and symptoms of Ceti Eel infestation include: headache, screaming, mild fever, behavioral and personality changes (compliance leading to dementia), slight bleeding from the ear, possibly death.
Bleeding from the ear, a common sign of Eel infestation.
There is no known treatment for Ceti Eel infestation. Tylenol or other analgesic medications may reduce headache and fever. Ceti Eel larvae do not seem to parasitize humans for any essential metabolic purpose, and occasionally will spontaneously re-emerge from their host’s ear with no perceptible alteration in size or shape.
Miraculously, infestation with Ceti Eel seems to have no detrimental effect on hearing.
If the infestation does not spontaneously resolve, death results.
Enjoy your trip!
1. Does this mean incontinent cats make better mousers?
2. In most people, presence of the protozoan is well tolerated, but avoid changing that litter box if you're pregnant.