Cat Scratch Fever

December 17, 2013

Nature, beautiful but deadly! Cats in particular, they're killing machines. From the bacteria they store under their claws to their lightning quick reflexes. And it turns out they have parasitic properties, too..

Toxoplasma gondii is a nasty parasite that originates only from cats. Parasites form a non-mutually beneficial relationship with their host, not killing them but feeding off their life essence. Apparently, parasites used to only refer to creatures visible to the naked eye, but now include microscopic critters. Not sure when the definition changed, I'm guessing around the time the microscope was invented.

Anyway, cats are the only hosts within which toxoplasma can sexually reproduce to complete and begin its lifecycle, spreading to humans and virtually all other warm-blooded animals. In non-sciencey terms, it begins with a cat eating a mouse or some other animal already infected with the parasite. Then, in the cat's intestines, a hotbed of acids and bacteria, cysts form and then burst, releasing little eggs. Then they escape the cat via their faeces and contaminate soil, food and water, awaiting a host. Once the eggs have entered a host, they burst and breed asexually, no more cat guts required.

Much is still unknown about what the effects these little guys have on us humans, but they've studied the hell out of how they affect mice & rats, who are guinea pigs in many medical studies, as they react very much as a human would to most things. Rodents infected with toxoplasma are suddenly attracted to the odour of cat urine, causing them to be eaten by the cats and starting the whole process over again.

But how does this affect me, Alex, and why should I give a fuck? Here are some estimations: Between 30-50 percent of the world's population is thought to be infected with our li'l buddy toxoplasma. Also, in the US alone, between 1989 and 2006, the population of cats went from 54.6 million to 81.7 million. That, and they produce 1.2 billion tons of cat shit per year. That's a lot of shit! And it could be more, could be less, who knows.

Questions, questions, questions! If rodents react similarly to this parasite, do humans? Is this part of the cat's evolutionary process, to infect it's owners with parasites that may make it more attractive to the owner?

This Swedish scientist thinks he knows more than me:

"We've not looked at behavioural changes in people infected with toxoplasma, as that's been dealt with by previous studies. Instead, we've shown for the first time how the parasite behaves in the body of its host, by which I mean how it enters the brain and manipulates the host by taking over one of the brain's neurotransmitters. We believe that this knowledge may be important for the further understanding of complex interactions in some major public health issues, that modern science still hasn't been able to explain fully. At the same time, it's important to emphasize that humans have lived with this parasite for many millennia, so today's carriers of Toxoplasma need not be particularly worried.."-Antonio Barragan, researcher at the Center for Infectious Medicine at Karolinska Institutet and the Swedish Institute for Communicable Disease Control.

Hmm.. a Swede named Antonio? Sounds fishy! That may be my brain worms talking, though. Plausible deniability; There are no worms, continue living your life, blindfolded!

But in one of this pseudo-Swede's laboratory experiments, human cells were infected with toxoplasma. After infection, the cells started secreting the neurotransmitter substance GABA.

GABA is a signal substance that, amongst other effects, inhibits the sensation of fear and anxiety. Disturbances of the GABA system are seen in people with depression, schizophrenia, bipolar diseases, anxiety syndrome and other mental diseases.

In another experiment on live mice, the team was able to trace the movement of infected cells in the body after introducing the parasite into the brain, from where it spread and continued to affect the GABA system.

So it may possibly exacerbate mental issues in humans? This Japanese man maybe.