Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study

Abstract

BackgroundLatent toxoplasmosis, protozoan parasitosis with prevalence rates from 20 to 60% in most populations, is known to impair reaction times in infected subjects, which results, for example, in a higher risk of traffic accidents in subjects with this life-long infection. Two recent studies have reported that RhD-positive subjects, especially RhD heterozygotes, are protected against latent toxoplasmosis-induced impairment of reaction times. In the present study we searched for increased incidence of traffic accidents and for protective effect of RhD positivity in 3890 military drivers.MethodsMale draftees who attended the Central Military Hospital in Prague for regular entrance psychological examinations between 2000 and 2003 were tested for Toxoplasma infection and RhD phenotype at the beginning of their 1 to1.5-year compulsory military service. Subsequently, the data on Toxoplasma infection and RhD phenotype were matched with those on traffic accidents from military police records and the effects of RhD phenotype and Toxoplasma infection on probability of traffic accident was estimated with logistic regression.ResultsWe confirmed, using for the first time a prospective cohort study design, increased risk of traffic accidents in Toxoplasma-infected subjects and demonstrated a strong protective effect of RhD positivity against the risk of traffic accidents posed by latent toxoplasmosis. Our results show that RhD-negative subjects with high titers of anti-Toxoplasma antibodies had a probability of a traffic accident of about 16.7%, i.e. a more than six times higher rate than Toxoplasma-free or RhD-positive subjects.ConclusionOur results showed that a common infection by Toxoplasma gondii could have strong impact on the probability of traffic accident in RhD negative subjects. The observed effects could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

The global burden of congenital toxoplasmosis: a systematic review

“…There are also increasing reports of neurological, psychiatric or psychomotor disorders related to "latent" toxoplasmosis, [31][32][33][34] and of a higher frequency of road traffic accidents among seropositive individuals. 35 Even if toxoplasmosis accounts for only a small fraction of these problems in the population, the global burden of disease attributable to toxoplasmosis is considerably greater than suggested by our CT data. In addition, since much toxoplasmosis can be prevented, at least in theory, by observing appropriate food hygiene, 36 the disease deserves a higher profile in GDB studies and should not be subsumed into other disease categories, such as "congenital disorders".…”

Physical and Mental Health Status in Toxoplasma-Infected Women before and 3 Years after They Learn about Their Infection: Manipulation or Side-Effects of Impaired Health?

“…In contrast, a positive correlation between the concentration of antibodies and the changes suggests that the observed effects represent transient vanishing effects of acute toxoplasmosis. Such positive correlations were observed, for example, for the probability of traffic accidents (Flegr et al, 2009) and predisposition to gestational diabetes mellitus (Kaňková et al, 2015), and now additionally for N-70 factors.…”

“…Many effects of toxoplasmosis are much stronger in Rh negative subjects and some can be detected only in them (Flegr et al, 2009;Kaňková et al, 2010). To detect such Rh dependent effects of toxoplasmosis and to increase the sensitivity of tests by decreasing the total variability of the output variables, it is always necessary to include the confounding variable Rh phenotype into the statistical models.…”

Pattern of money allocation in experimental games supports the stress hypothesis of gender differences in Toxoplasma gondii-induced behavioural changes

“…higher dopamine in infected rodents and humans (stibbs 1985(stibbs , Novotná et al 2005(stibbs , skallová et al 2006, association of toxoplasmosis with schizophrenia (e.g. torrey and Yolken 2003), prolonged reaction times (Havlíček et al 2001, Novotná et al 2008, and higher risk of traffic accidents (Flegr et al 2009, Kocazeybek et al 2009). …”

“…the mechanism of the effect of latent toxoplasmosis on human behaviour is unknown; however, we have some indices of deteriorated physical functioning in T. gondiiinfected subjects. these include prolonged simple reaction times (Havlíček et al 2001, Novotná et al 2008, and higher risk of traffic accidents (Flegr et al 2009, Kocazeybek et al 2009) in infected subjects. Deteriorated physical functioning of T. gondii-infected subjects possibly leading to shorter life expectancy could also explain the unexpected phenomenon of decreased seropositivity in the highest age groups in many prevalence studies (e.g.…”