Do you notice a difference between the maps? Probably not considering there hardly is any discrepancy between the two. In the upper map, found on worldmapper.org , territory size shows the proportion of all road traffic accident deaths worldwide that occurred there. In the second lower map (which looks strikingly similar to the upper one to me), the territory size shows the proportion of the world population that lives there. If latent toxoplasmosis really increases the risk of traffic accidents, wouldn't we expect the countries with higher prevalence of this infection to have more road deaths? For example, rather than remaining relatively consistent with the proportion of the population that lives there, wouldn't we expect to see a higher amount of road deaths in France, Germany, the Netherlands, and Brazil where prevalence of toxoplasmosis infection exceeds 70 percent of the total population?