Latent infection of the globally spread parasite Toxoplasma gondii in humans has been associated with changes in personality and behavior. Numerous studies have investigated the effect of toxoplasmosis on depression, but their results are inconsistent. Our study focused on the effect of latent toxoplasmosis on depression in men and women in association with their fertility. In 2016–2018, we recruited clients (677 men and 664 women) of the Center for Assisted Reproduction and asked them to complete a standardized Beck Depression Inventory-II. In women without fertility problems, we found higher depression scores in Toxoplasma-positive than in Toxoplasma-negative (p = 0.010, Cohen’s d = 0.48). Toxoplasma-positive infertile men, on the other hand, had lower depression scores than Toxoplasma-negative infertile men (p ≤ 0.001, Cohen’s d = 0.48). Our results are consistent with the previously described effects of latent toxoplasmosis, which seem to go in opposite directions regarding the effect on personality and behavior of men and women. Our results could be explained by gender-contrasting reactions to chronic stress associated with lifelong infection. This suggests that due to gender differences in the impact of latent toxoplasmosis, future studies ought to perform separate analyses for women and men.

The emotion of disgust protects individuals against pathogens, and it has been found to be elevated during pregnancy. Physiological mechanisms discussed in relation to these changes include immune markers and progesterone levels. This study aimed to assess the association between steroids and disgust sensitivity in pregnancy. Using a prospective longitudinal design, we analyzed blood serum steroid concentrations and measured disgust sensitivity via text-based questionnaires in a sample of 179 pregnant women during their first and third trimesters. We found positive correlations between disgust sensitivity and the levels of C19 steroids (including testosterone) and its precursors in the Δ⁵ pathway (androstenediol, DHEA, and their sulfates) and the Δ⁴ pathway (androstenedione). Additionally, positive correlations were observed with 5α/β-reduced C19 steroid metabolites in both trimesters. In the first trimester, disgust sensitivity was positively associated with 17-hydroxypregnanolone and with some estrogens. In the third trimester, positive associations were observed with cortisol and immunoprotective Δ⁵ C19 7α/β-hydroxy-steroids. Our findings show that disgust sensitivity is positively correlated with immunomodulatory steroids, and in the third trimester, with steroids which may be related to potential maternal-anxiety-related symptoms. This study highlights the complex relationship between hormonal changes and disgust sensitivity during pregnancy.

Toxoplasma gondii (Nicolle et Manceaux, 1908), an intracellular parasite that causes toxoplasmosis, infects a third of the human population. Latent toxoplasmosis has been linked to altered immune responses, including elevated proinflammatory cytokines. In early pregnancy, the immune system adapts to balance inflammation and foetal tolerance. This study assessed whether pregnant women in the first trimester infected with Toxoplasma gondii have different cytokine levels than uninfected women. This study also examined whether women with discordant test results for toxoplasmosis represent a distinct group or a mixed group composed of infected women with unusually low levels of anti-Toxoplasma antibodies and uninfected women with high levels of cross-reacting antibodies. We measured 18 cytokines (IL-1β, IL-1ra, IL-2, IL-4, IL-7, IL-9, IL-17A, Eotaxin, FGF basic, G-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α) in 78 pregnant women, classified as Toxoplasma-positive, Toxoplasma-negative or Toxoplasma-discordant (negative by IgG ELISA, positive by complement fixation test [CFT]). Using exploratory factor analysis, we identified two factors, the first explaining 29.6% and the second 24.9% of the total variability in cytokine concentrations. Toxoplasma-positive women scored significantly higher in the second factor, primarily associated with cytokines linked to Th1-driven inflammation and cellular immunity. Specifically, these women exhibited elevated levels of IL-1β, IL-1ra, IL-2, FGF basic and PDGF-BB compared to Toxoplasma-negative women. This finding suggests that pregnant women with latent toxoplasmosis experience some degree of chronic inflammation. Additionally, our results indicate that Toxoplasma-discordant women are likely Toxoplasma-negative individuals with detectable anti-Toxoplasma IgM antibodies. However, as this study focused on pregnant women, further research is necessary to validate these conclusions in broader populations.