The Mother of All Parasites

Via The Anti-Toxo: Future Microbiology reports the discovery of a missing-link apicomplexan and its implications.

Symbiosis and parasitism are thus wide-spread in both the dinoflagellates and apicomplexans, suggesting that modern parasites like Plasmodium spp. and Toxoplasma likely started out as mutualistic symbionts that initially nourished their animal hosts before turning to parasitism. These symbiotic/parasitic relationships thus extend back in evolutionary time to the earliest origins of the animals, which means that either as parasites or symbionts, these protists have been interacting with the animal immune system since its inception. As a consequence of this protracted dance, malaria parasites are exquisitely well-equipped to evade our immune system: a sobering harbinger for malaria vaccine prospects.

Toxoplasmosis and You

Today's featured parasite is the stealthy and adaptable protozoan, Toxoplasma gondii.

This is the cat-litter bug that causes miscarriages and birth defects. The cat-loving parasite that lures rats to their deaths and causes traffic accidents. The latest schizophrenia suspect and a possible cause of epilepsy, psychosis, and migraines.

T. gondii may be making society rigid and neurotic, men more masculine, stupider, or more surly, and women more promiscuous. And if you think things are bad in the northern hemisphere, you should see the Brazilian strains.

About 16% 11% 33% of Americans are infected; infection rates are much higher in tropical countries (and France). Wikipedia tells the sad tale of Louis Wain, English cat artist, late-onset schizophrenic, and poster-child for the toxoplasmosis-schizophrenia connection.

T. gondii has its own book, conference, mugs and a blog, The Anti-Toxo, where you can follow mankind's losing battle with our one-celled masters.

Image by kqedquest. Some rights reserved.

Toxoplasma

Technovelgy speculates about Toxoplasma Parasite Mind Control in rats and people:

Oxford scientists discovered that the minds of the infected rats have been subtly altered. In a series of experiments, they demonstrated that healthy rats will prudently avoid areas that have been doused with cat urine. In fact, when scientists test anti-anxiety drugs on rats, they use a whiff of cat urine to induce neurochemical panic. However, it turns out that Toxoplasma-ridden rats show no such reaction. In fact, some of the infected rats actually seek out the cat urine-marked areas again and again. The parasite alters the mind (and thus the behavior) of the rat for its own benefit. [...]
Dr. Torrey got together with the Oxford scientists, to see if anything could be done about those parasite-controlled rats who were driven to hang around cat urine-soaked corners (waiting for cats). According to a recent press release, it turns out that haloperidol restores the rat's healthy fear of cat urine. In fact, antipsychotic drugs were as effective as pyrimethamine, a drug that specifically eliminates Toxoplasma.

From the press release from Imperial College London:

Research published today in Procedings of the Royal Society B, shows how the invasion or replication of the parasite Toxoplasma gondii in rats may be inhibited by using anti-psychotic or mood stabilising drugs.
The researchers tested anti-psychotic and mood stabilising medications used for the treatment of schizophrenia on rats infected with T. gondii and found they were as, or more, effective at preventing behaviourial alterations as anti-T. gondii drugs. This led them to believe that T. gondii may have a role in the development of some cases of schizophrenia.