Gender differences in behavioural changes induced by latent

21 22 There is growing evidence that the protozoan Toxoplasma gondii modifies behaviour of its 23 intermediate hosts including humans, where it globally infects about 20-60 % of the population. 24 Although it is considered asymptomatic in its latent stage, it was previously found to have 25 remarkable and gender different effects on the personality factors A (warmth), G (rule 26 consciousness), L (vigilance, mistrust) and Q3 (self control, self image) from Cattell's 16PF 27 Questionnaire. We performed a double blind experiment testing 72 and 142 uninfected and 20 28 and 29 infected men and women in order to behaviourally verify these gender differences. Our 29 composite behavioural variables Self Control and Clothes Tidiness (analogue both to the 16PF 30 factors G – conscientiousness and Q3 – self control) showed a significant effect of the 31 toxoplasmosis-gender interaction with infected men scoring significantly lower than uninfected 32 men and a trend in the opposite direction in women. The effect of the toxoplasmosis-gender 33 interaction on our composite behavioural variable Relationships (analogue to factor A – warmth) 34 approached significance; infected men scored significantly lower than uninfected men whereas 35 there was no difference in women. In the composite behavioural variable Mistrust (analogue to 36 factor L), the pattern was affected by living environment (rural vs. urban). Possible 37 interpretations of the gender differences are discussed.