Pereira F E, Sampaio A P, Musso C, Castelo J S
Departamento de Patologia do Centro Biomédico, Universidade Federal do Espírito Santo, Vitória, ES.
Rev Soc Bras Med Trop. 1991 Oct-Dec;24(4):217-21. doi: 10.1590/s0037-86821991000400003.
To clarify the existence of reinfection in children bearing an established Ascaris lumbricoides infection, the authors evaluated the weight and the length of worms collected from ten cases of ascaridiasis. The worm burden was greater than 27 worms in nine cases. In seven cases the weight and the length of worms showed little variation, with unimodal distribution of values, suggesting that all the worms in each case belong to the same population, originated from a single brood infection or from successive infections over small time intervals. In three cases there was great variation in worm size indicated by the different values for the means and medians and by the high values for the standard deviation and coefficient of variation. In these three cases there was a bimodal distribution of worm's size suggesting the coexistence of two distinct populations: one, less numerous, composed of mature worms and the other, more numerous, composed of immature worms, in two cases, and two distinct populations of immature worms in one case. The existence of worms in different stages of maturation indicates that the less mature population was acquired when the mature worms were established in the gut. These results indicate that the reinfection with Ascaris in children bearing an established infection is not rare and resistance induced by a preexisting infection is not the rule.
为明确已确诊感染蛔虫的儿童中再感染的情况，作者评估了从10例蛔虫病患者体内收集的蛔虫的重量和长度。9例患者的蛔虫负荷超过27条。7例患者的蛔虫重量和长度变化不大，数值呈单峰分布，这表明每个病例中的所有蛔虫都属于同一群体，源自单次感染或短时间内的连续感染。3例患者的蛔虫大小差异很大，均值和中位数的不同数值以及标准差和变异系数的高值都表明了这一点。在这3例患者中，蛔虫大小呈双峰分布，表明存在两个不同的群体：在2例中，一个群体数量较少，由成熟蛔虫组成，另一个群体数量较多，由未成熟蛔虫组成；在1例中，存在两个不同的未成熟蛔虫群体。不同成熟阶段蛔虫的存在表明，在成熟蛔虫在肠道内定植时获得了较不成熟的群体。这些结果表明，已确诊感染蛔虫的儿童中再感染并不罕见，先前感染所诱导的抵抗力并非普遍规律。
