The most important part. Note that those people which got their blood checked for toxo were all "seemingly" healthy without any outbreak.
Also, if you check the whole video, you will see the scientist saying that, unlike popular belief, the parasites do leave the cysts in the brain even on healthy people, just to go back later into cyst form.
Here is a recap from an older thread:
So, if i told you that around 50% of the world's population are infested by a parasite which triples the chances for you to run into a car accident, you would call me mad, no? But let's see what science has to say about this.
Let's start gently with the wiki article
It is estimated that between 30% and 65% of all people worldwide are infected with toxoplasmosis. However, there is large variation between countries: in France, for example, around 88% of the population are carriers, probably due to a high consumption of raw and lightly cooked meat.  Germany, the Netherlands and Brazil also have high prevalences of around 68%, over 80% and 67% respectively. In Britain about 22% are carriers, and South Korea's rate is 4.3%.
Studies have been conducted that show the toxoplasmosis parasite may affect behavior and may present as or be a causative or contributory factor in various psychiatric disorders such as depression, anxiety and schizophrenia. In 11 of 19 scientific studies, T. gondii antibody levels were found to be significantly higher in individuals affected by first-incidence schizophrenia than in unaffected persons. Individuals with schizophrenia are also more likely to report a clinical history of toxoplasmosis than those in the general population. Recent work at the University of Leeds has found that the parasite produces an enzyme with tyrosine hydroxylase and phenylalanine hydroxylase activity. This enzyme may contribute to the behavioral changes observed in toxoplasmosis by altering the production of dopamine, a neurotransmitter involved in mood, sociability, attention, motivation and sleep patterns. Schizophrenia has long been linked to dopamine dysregulation.Correlations have been found between latent Toxoplasma infections and various characteristics:
Decreased novelty seeking behaviour
Lower rule-consciousness and greater jealousy (in men)
Greater warmth, conscientiousness and moralistic behavior (in women)Studies have found that toxoplasmosis is associated with an increased car accident rate in people with Rh-negative blood. The chance of an accident relative to uninfected people is increased roughly 2.5 timesthis is all from http://en.wikipedia.org/wiki/ToxoplasmosisThe study suggests that male carriers have shorter attention spans, a greater likelihood of breaking rules and taking risks, and are more independent, anti-social, suspicious, jealous and morose. It also suggests that these men are deemed less attractive to women. Female carriers are suggested to be more outgoing, friendly, more promiscuous, and are considered more attractive to men compared with non-infected controls. The results are shown to be true when tested on mice, though it is still inconclusive. A few scientists have suggested that, if these effects are genuine, prevalence of toxoplasmosis could be a major determinant of cultural differences.
Let's look at some real studies
Take a look at this pdf.
Some less scientific but even more striking part of this pdf goes like this
http://www.med.ust.edu.ye/yjms/pdf/v...xoplasmosi.pdfIt might seem anecdotal that in a group of 29 Toxoplasma negative professors from our experimental set, there are 10 present or past decision-makers (heads of department, vicedeans and deans) while among 14 Toxoplasma positive professors there is only a single head of department.
Here is one study linking it to schizophrenia
Because animal studies have demonstrated that mice infected with T. gondii have impaired motor performance,10,11 human studies were carried out on volunteer blood donors. A computerized simple reaction time test (reaction to the appearance of a white square) was given to 60 adults positive for antibodies to T. gondii and 59 adults negative for such antibodies. Those with latent infection performed significantly more poorly (analysis of covariance, P = 0.011) and appeared to lose their concentration more quickly, although the effect of the infection was modest and explained less than 10% of the variability in performance.source:The difference in seroprevalence of toxoplasmosis in these 2 samples suggests that Toxoplasma-infected subjects have a 2.65 times higher risk of traffic accidents than Toxoplasma-free subjects
source: http://priory.com/pharmol/toxoplasmosis.htmJ.Flegr et al, 2003(10) did a study on 857 military conscripts and found
toxoplasma positive subjects mostly had just elementary education,
significantly lower verbal intelligence and significantly lower factor of
novelty seeking. Other studies on humans with latent toxoplasmosis
have also shown significant impaired psychomotor performance and prolonged
If the source i cannot find currently is right, then around 90% of cats are infected, plus are the only host in which the parasite reproduces sexually.
Infected mice, often by cat feces, have their behavior shifted by the parasite, in such a way that they lose their fear of cats, eventually resulting in them getting eaten (therefore infecting un-infected cats and enable themselves to reproduce sexually inside the cat's intestines once again).
One has to wonder, when our pets get examined for all kind of parasite infections, and treated for all kind of parasites on a less than yearly basis, why humans are rarely examined for such even when there are no apparent symptoms.
When over 50% of the population has toxoplasmosis, and the effects are that dramatic like 2.65x higher chance of getting involved in a car accident, then wouldn't it be normal to get checked for it often?