A small article with the headline "Parasite posing a danger to humans" caught my eye in last Sunday's paper. It seems that toxoplasma gondii, a parasite that already affects between 10 and 20 percent of all Americans, has been linked to an increased risk of schizophrenia and bipolar disorder and, if that weren't bad enough, a Danish study has also found a possible link between infection with this parasite and an increased incidence of suicide in women. Although the connection between parasitic infection and certain types of mental illness is intriguing to ponder, it was the following that stopped me dead in my tracks as I read this article:
"The parasite's optimal host is the cat - it can complete its reproductive cycle only in the feline intestinal tract. It has developed an ingenious mechanism for survival. It turns rodents into willing cat food.
When a rat or a mouse is infected, it suddenly flips from being petrified of cats to being attracted to them. Studies have shown that the cells in the rodent brain that regulate sexual arousal become active when mice and rats get a whiff of cat urine, suggesting the smell turns them on. As a result, they drop their guard, the cats eat them - and the parasite can reproduce at will."
Wow, that is one smart parasite.
After I showed the article to my husband, he commented that this would make a great plot device for a murder mystery and suggested that I should blog about it. After all, it has been a time honored technique in both real life and fiction to stage an actual murder so that it would appear to have been a suicide. Deliberately infecting someone with toxoplasma gondii in anticipation that she will later kill herself might not be the most efficient way to do someone in, but it is something that would be pretty hard to prove and it is also something that would likely slide completely under the radar of most law enforcement agencies. So, if a bad guy wants to get rid of his wife but wants to keep his hands clean - both literally and figuratively - all he has to do is keep letting his wife clean Fluffy's litter box and let toxoplasma gondii take care of the dirty work.
And yet, while a plan such as this might actually work in real life, I'm not so sure it would work all that well in fiction. When I read any kind of novel, but most especially crime fiction, one of the things I crave is believability; the characters must come across as real people and the situations must seem plausible. Even though coincidences do occur in real life, I absolutely hate it when an author needs to rely too heavily on coincidental happenings in order to make the various strands of a plot line hold together.
I also hate it when an author ignores the concept of probability; this is definitely attributable to the fact that I once considered becoming an actuary and took a number of college level probability and statistics courses in preparation for doing so. Although I never did find work as an actuary, all these years later I remain very much tuned in to the probability of whether or not any particular event or combination of events might actually happen, in life as well as in fiction.
I am way more accepting of the occurrence of the improbable in real life than I am in fiction because an author has a level of control over what happens to his or her characters that is just not available to any of us in real life. And for me it is not especially satisfying to have the solution to a crime revealed as something so totally obscure or unlikely that I find myself muttering at its revelation, "now what are the odds of something like that actually happening."
So, I'm throwing out as a challenge for anybody reading this to come up with a credible piece of crime fiction that uses toxoplasma gondii as the murder weapon.
BTW, although I first read about toxoplasma gondii in the July 8 edition of the Star Ledger, a more complete version of this same article first appeared in the July 6 edition of the Los Angeles Times and can be found here.