Hopeless Trekkie

In one of the most cringe worthy contamination scenarios brought about by a group of trained space scientists, the Enterprise crew is exposed to a disease causing agent manifesting bizarre behaviors in the affected.  The episode opens with an away team, led by Spock, inspecting the planet Psi 2000 to investigate a research team that was left on the dying planet.  The frozen remains of the scientists showed that they perished under mysterious circumstances.  After much consideration, the Enterprise away team’s findings were inconclusive, but they had been in the area long enough for the lieutenant you have never seen before to come into contact with a red liquid oozing along a console.  Perhaps this was more a product of the exaggerated drama of early television, but I hope most biologists would wince at someone touching a possibly contaminated space site with their bare hand and then rubbing his or her face so thoroughly afterward.  It really begs the question why one would bother to wear an isolation suit in the first place if they take part of it off in the middle of their work.  But contrived plot points aside, the infection that spread through the ship resulted in hilarious shenanigans for the crew, and a touching emotional dialogue between Kirk and Spock.

With these bizarre antics, this first season episode reveals much about the main characters.  For example, the fact that Nurse Chapel confesses her love for Spock so early in the season was somewhat heavy, and without much buildup.  It must have been embarrassing once the effects of the contagion subsided, and everyone was made aware of how they were acting.  Even in the real world, despite our illusion of control over our actions, our sense of cognitive authority is surprisingly tenuous.

Behavior changing infections are not new to science, but a few extremely fascinating ones have recently been described.  In ‘The Naked Time’, the infectious agent is characterized as a mixture of chemicals, which are transferred through sweat to alter brain function and reduce inhibitions.  The episode is vague about exactly what these chemicals are, and we are left to speculate as to their origin.  Could they have been created by the scientists for some purpose that got out of hand?  The details of the exact mechanism and origin were not important for the episode, because the plot focused more on character development and interpersonal relationships, with the removal of inhibition functioning as more of a gimmick.  However, I am more interested in the science behind this plot, and the real life equivalent to behavior altering contagions is actually more fascinating and complex.

A rather elegant example of how a type of parasite can facilitate its transmission through manipulation of its host is in the life cycle of Dicrocoelium dendriticum.  Matthew Inman’s comic The Oatmeal describes this phenomenon amusingly, and with pictures!  The idea is that D. dendriticum requires three animal hosts to complete its lifecycle: a snail, an ant, and a cow.  It can be transmitted to the snail or the ant by being present in their food sources, the waste products of the previous host, but the mechanism of transmission from ant to cow involves controlling the ant’s behavior.  Once infected, the ant will be coerced into climbing a blade of grass and waiting for a cow to eat it.

Another interesting example of biological hijacking is the fungus Ophiocordyceps camponoti-rufipedis, which has been described as producing ‘zombie ants’.  This ant-hypnotizing pathogen drives the ant to move to a high location, such as a blade of grass, before the infection kills it.  The fungal reproductive body, now optimally located to spread spores, grows out of the ant’s head.

It is a shame that ‘The Naked Time’ described its infectious agent as a group of chemicals, because it missed out on an opportunity to create a space virus that could evolve and perpetuate its existence by spreading to new hosts.  In the above examples, the parasites survived and spread to the detriment of at least one host, the ants; in Star Trek at least one crewman died along with all the scientists on the planet.  If it had been a living species, maybe the infectious agent could have controlled host behavior to optimize its infection rate.

Although my real world examples were specific to ants, humans are just as vulnerable to mind altering disorders, and many types of general mental deterioration.  The Psi 2000 contagion merely removed human inhibition to reveal underlying, and possibly embarrassing, personality traits.  We can never truly isolate ourselves from what nature can cultivate.  Without inhibitions or rational thought, our most intimate desires could become naked.

For more information on ‘Zombie Ants’, read the article published in Communicative & Integrative Biology:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3204140/