Flegr J, Hrusková M, Hodný Z, Novotná M, Hanusová J
Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
Parasitology. 2005 Jun;130(Pt 6):621-8. doi: 10.1017/s0031182005007316.
Between 20% and 60% of the population of most countries are infected with the protozoan Toxoplasma gondii. Subjects with clinically asymptomatic life-long latent toxoplasmosis differ from those who are Toxoplasma free in several behavioural parameters. Case-control studies cannot decide whether these differences already existed before infection or whether they were induced by the presence of Toxoplasma in the brain of infected hosts. Here we searched for such morphological differences between Toxoplasma-infected and Toxoplasma-free subjects that could be induced by the parasite (body weight, body height, body mass index, waist-hip ratio), or could rather correlate with their natural resistance to parasitic infection (fluctuating asymmetry, 2D : 4D ratio). We found Toxoplasma-infected men to be taller and Toxoplasma-infected men and women to have lower 2D : 4D ratios previously reported to be associated with higher pre-natal testosterone levels. The 2D : 4D ratio negatively correlated with the level of specific anti-Toxoplasma antibodies in Toxoplasma-free subjects. These results suggest that some of the observed differences between infected and non-infected subjects may have existed before infection and could be caused by the lower natural resistance to Toxoplasma infection in subjects with higher pre-natal testosterone levels.
大多数国家20%至60%的人口感染了原生动物刚地弓形虫。患有临床无症状的终身潜伏性弓形虫病的人与未感染弓形虫的人在几个行为参数上有所不同。病例对照研究无法确定这些差异是在感染前就已存在，还是由受感染宿主大脑中弓形虫的存在所诱发。在这里，我们寻找受弓形虫感染和未感染弓形虫的个体之间可能由寄生虫引起的形态学差异（体重、身高、体重指数、腰臀比），或者更可能与他们对寄生虫感染的天然抵抗力相关的差异（波动不对称性、2D:4D指比）。我们发现感染弓形虫的男性更高，感染弓形虫的男性和女性的2D:4D指比更低，此前有报道称该指比与较高的产前睾酮水平相关。在未感染弓形虫的个体中，2D:4D指比与特异性抗弓形虫抗体水平呈负相关。这些结果表明，在感染和未感染个体之间观察到的一些差异可能在感染前就已存在，并且可能是由产前睾酮水平较高的个体对弓形虫感染的天然抵抗力较低所导致的。
