Guest Post – Toxoplasmosis and Evil Cats
One possible way for me to finish my PhD, is to publish three first author articles. So unless I’ve grossly misunderstood the context; I present to you my second DOTW! guest article.

My second greatest fear in life is being mediocre. What’s my greatest fear you ask? Getting a job and leaving the life of study. I want to achieve something before I’m put in a wooden box and forgotten about. So the fact that I haven’t yet cured cancer or even saved anybody’s life leads me to ask, what scientific reason could there be for my lack of world domination?

Like a lot of great thinkers, I instinctively took umbrage at my cat.

Cat me if you can: It

In Australia in the year 2000 there were an estimated 2.4 million domesticated cats. That’s about 1 cat for every 10 people. Consequently, exposure to cats is reasonably inevitable. What’s even more worrying though is that exposure to cat faeces is practically unavoidable – especially if you’ve ever patted one of those creatures. Try not to think about it too much, but please continue reading.

One of the great thing about cats is that they form a natural reservoir for a parasite known as Toxoplasma gondii, a little protozoan creature that is best spread through eating cat poo. Though maternal transmission and eating uncooked meat (not necessarily uncooked cat meat) is also a great way of developing toxoplasmosis. If you’re thinking to yourself “I generally avoid eating cat poo.” There is a good chance you’ve done a good job of it. A study carried out in the U.S in 1999-2000 found that prevalence of the lifelong IgG (antibody) to toxoplasma was around 16% in persons 12 years and older. Consequently, 1 in 6 of you people reading this probably have brain cysts due to toxoplasma. Oh no! On the plus side, 5 in 6 of you don’t. Yay!

Infection with toxoplasma isn’t necessarily the end of the world. In fact for most people the initial infection is mild and undetectable or moderately flu like, passing within a few weeks. The real risk of toxo infection is to pregnant women. Pregnant women should be especially mindful to wash their hands a lot when around animals and avoid raw meat, so as to prevent transmission to the fetus and the risk of complications due to a weakened immune system. Transfer of infection to the fetus can only occur if the mother is infected for the first time during pregnancy, however risks to the fetus include chorioretinitis, hydrocephalus, intracranial calcification, mental retardation and spontaneous abortion.

The only other people who seem to obviously get sick from toxo are the immuno-compromised. Such as those with HIV/AIDS, transplant recipients or people living with cancer. This is largely because an infection with toxo is never completely resolved. The majority of the parasites are cleared, however some toxo hold up in areas such as nervous or muscle tissue. An equilibrium between the immune system and the parasite is achieved, and for most people this equilibrium is sufficient until something else kills them, like a traffic accident. Unfortunately compromising the immune system can convert latent infection in to active infection, though there are treatments available to combat this.

The phenomenon of sustained equilibrium between host and pathogen is known as a latent toxoplasmosis, and is largely thought to be clinically asymptomatic. But is it really?

New data is constantly being turfed up, but evidence for behavioral change following infection with T. gondii is accumulating, and with it my excuses for being average.* Perhaps some of the most amusing research points to an increased likeliness for people with latent toxoplasmosis to suffer mental disorders and be involved in traffic accidents. How this occurs isn’t entirely clear, but it may have something to do with the fact that latent toxoplasmosis has been shown to reduce reaction times compared to uninfected individuals Adding to the complexity of this issue is the fact that presence of the Rh Antigen on red blood cells can influence the level of disease severity. Further research needs to be done, as most of the studies are on small sample groups. So next time you see someone who seems a little slow, why not suggest they get their brain screened for toxoplasmic cysts and enrol them in a clinical trial of some kind.

What seems most contradictory though, is the fact that people who are most surrounded by cats, namely older single women, are still single. “Novel research” indicates that latently infected women are more likely to be promiscuous and have increased intelligence levels. The only explanation I can see for continued singleness, is that the same women are looking for men who like cats. Unfortunately latent toxo infection in males has been reported to make them antisocial, aggressive, suspicious and jealous. Irony!

Infection with toxoplasma isn’t really something to be worried about, though it does fall in to the category of ‘diseases you actually could have.’ All in all, this parasite functions to increase the diversity of the social milieu through a range of mental disorders, and serves to eradicate cat lovers through traffic accidents.

*I don’t actually know that I have toxoplasma, I could just be lazy, albeit brilliant.

Entered at final edit by JB – Don’t get ahead of yourself, your not brilliant… Also I want it to be very clear, the caption was written by Matt, aim your hate, scorn, lol’s at him.


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Jones JL, Kruszon-Moran D, & Wilson M (2003). Toxoplasma gondii infection in the United States, 1999-2000. Emerging infectious diseases, 9 (11), 1371-4 PMID: 14718078

Flegr, J., Klose, J., Novotná, M., Berenreitterová, M., & Havlíček, J. (2009). Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study BMC Infectious Diseases, 9 (1) DOI: 10.1186/1471-2334-9-72

YERELI, K., BALCIOGLU, I., & OZBILGIN, A. (2006). Is Toxoplasma gondii a potential risk for traffic accidents in Turkey?☆ Forensic Science International, 163 (1-2), 34-37 DOI: 10.1016/j.forsciint.2005.11.002

NOVOTNÁ, M., HAVLÍČEK, J., SMITH, A., KOLBEKOVÁ, P., SKALLOVÁ, A., KLOSE, J., GAŠOVÁ, Z., PÍSAČKA, M., SECHOVSKÁ, M., & FLEGR, J. (2008). Toxoplasma and reaction time: role of toxoplasmosis in the origin, preservation and geographical distribution of Rh blood group polymorphism Parasitology, 135 (11) DOI: 10.1017/S003118200800485X



Filed under Guest Post

3 responses to “Guest Post – Toxoplasmosis and Evil Cats

  1. isabel

    tiene cura la toxoplasmosis en enfermos con sida y si se curan cuales son las secuelas de esta enfermedad toxoplasmosisi

    • Thanks to Julie for the translation on behalf of Mat
      Hola, gracias por el email.
      Siento que su hermano esté enferma. Lamentablemente, nosotros aqui de DOTW no somos medicos (somos cientificos). Por eso, es mejor que hable con los medicos de su hermano sobre las opciónes para traitamiento. Su hermano esta inmunocomprometido y por eso lamentablemente, no puede combatir su infección de toxoplasma. Mi interpretación de literatura sobre toxoplasma indica que drogas como Pyrimethamine y sulfadiazine son utilizado a menudo para tratar toxoplasma satisfactoriamente. El proceso dura 3-6 semanas y hay un riesgo de efectos secundarios como sarpullidos
      y diarrea. Espero que esto información es útil.

  2. isabel

    quiero saber si los enfermos con vih que tienen toxiplasmosis tienen cura de la toxiplasmosi mi hermano convulsionó unas ocho veces, pasando dos meses, le duele la cabeza,ojos, dolor de barriga y en la espalda,fiebre,tiene la piel de la cabeza y cara, casposa, sudoraciones y perdida del conocimiento

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