Wilkins H A, Goll P H, Marshall T F, Moore P J
Trans R Soc Trop Med Hyg. 1984;78(2):227-32. doi: 10.1016/0035-9203(84)90283-9.
During a three-year period of effective control of Schistosoma haematobium transmission by molluscicide application the mean number of S. haematobium ova passed by subjects in the treated area fell in an exponential manner which suggested that the mean life span of the worm was 3.4 years. Parallel observations were made in a similar but untreated area. A comparison of the observations in these two areas suggested that in the untreated area subjects of all ages acquired infection during the course of the study. At the end of the study over 50% of the egg output in most age groups in the untreated area appeared to come from worms acquired during the preceding three years. There were substantial differences between age groups in the amount of infection acquired. Children, aged between eight and ten years at the end of the study, appeared to be passing perhaps a thousand times more ova from worms acquired during the preceding three years than were middle-aged subjects. Preliminary observations suggest that age- and sex-related differences in the pattern of water contact may not fully account for age- and sex-related differences in the rate of acquisition of infection and its prevalence. The probable significance of protective immunity in the epidemiology of schistosome infections is discussed.
在通过施用杀螺剂对埃及血吸虫传播进行三年有效控制期间，治疗区域内受试者排出的埃及血吸虫卵平均数呈指数下降，这表明该蠕虫的平均寿命为3.4年。在一个类似但未进行处理的区域进行了平行观察。对这两个区域观察结果的比较表明，在未处理区域，所有年龄段的受试者在研究过程中都感染了血吸虫。在研究结束时，未处理区域大多数年龄组中超过50%的虫卵似乎来自前三年感染的蠕虫。不同年龄组感染程度存在很大差异。研究结束时年龄在8至10岁之间的儿童，其在前三年感染的蠕虫排出的虫卵数量可能比中年受试者多一千倍左右。初步观察表明，与年龄和性别相关的接触水模式差异可能无法完全解释感染率及其流行率方面与年龄和性别相关的差异。文中讨论了保护性免疫在血吸虫感染流行病学中的可能意义。
