A 2-year prospective study in China provides epidemiological evidence for resistance in humans to re-infection with Schistosoma japonicum
A 2-year prospective study in China provides epidemiological evidence for resistance in humans to re-infection with Schistosoma japonicum
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DOI：
10.1080/00034989958131
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发表时间：
1999-09-01
影响因子：
--
通讯作者：
McManus, DP
中科院分区：
文献类型：
--
作者：
Li, YS;Sleigh, AC;McManus, DP
1996年，对居住在洞庭湖区中国地区的250人进行了为期两年的研究。所有人都感染过或曾经感染过日本血吸虫。尽管只在75名受试者的粪便样本中检测到日本血吸虫卵，但所有受试者都接受了吡喹酮治疗。1998年，这些受试者中有213人(85.5%)，当时的平均数(S.D.)年龄为40.2(14.2)岁，为最终评估提供了粪便样本。1998年，213人中有49人(23%)被发现再次感染，受感染者的几何平均感染强度为64.5个蛋/克粪便。再感染率以10岁组最高，随年龄增长而下降，男性高于女性(27.3%vs8.3%；P<；0.005)。感染男性的平均感染强度也高于感染女性[72.4vs17.8(2.5)个鸡蛋/克；P<；0.005]。受试者的水接触是通过活动日记估计的，在两年的研究期间持续141d，并以皮肤暴露表示，以m(2)-分钟/天为单位。一组受试者的平均曝光量是通过对该组内每个受试者的曝光量的四根变换(即归一化)值的平均值进行去变换来计算的。总体而言，213人的平均暴露时间为6.2米(2)-分钟/天。职业的差异导致男性的平均水暴露比女性高得多(9.2比1.1米(2)-分钟/天)。由于特定年龄的接触与特定年龄的再感染强度之间存在负相关，随着年龄的增加，再感染强度显著降低，这并不是由于接触水的减少。相反，这项为期两年的队列研究的结果提供了与年龄相关的对再次感染日本血吸虫的抵抗力的证据。根据研究结束时的流行病学结果和接触水的数据，213名受试者被归类为“易感”(N=49；23%)、“不易感”(N=29；13.6%)或“不确定状态”(N=135；63.4%)。因此，确定了78名在免疫遗传学方面具有潜在信息量的受试者。对这些个体的进一步研究将有助于阐明免疫遗传状态在人类对日本血吸虫免疫中的作用。
In 1996, 250 people living in the Dongting-Lake region of China were selected for a 2-year study. All had been or were infected with Schistosoma japonicum. All were treated with praziquantel, although eggs of S. japonicum were only detected in stool samples from 75 of the subjects. In 1998, 213 (85.5%) of these subjects, then with a mean (S.D.) age of 40.2 (14.2) years, provided stool samples for final assessment. Forty-nine (23%) of the 213 were found to be re-infected in 1998, with a geometric mean intensity of infection among the infected of 64.5 eggs/g faeces. The rate of re-infection was highest among those aged < 10 years, declining with increasing age, and higher in males than females (27.3% v. 8.3%; P < 0.005). The mean intensity of infection among the infected males was also higher than that among the infected females [72.4 (4.8) v. 17.8 (2.5) eggs/g; P < 0.005].Water contact by the subjects was estimated from activity diaries, for 141 days over the 2-year study period, and expressed as skin exposure, in m(2)-min/day. The mean exposure of a group of subjects was calculated by detransforming the mean of the fourth-root-transformed (i.e. normalized) values for the exposures of each subject within the group. Overall, the 213 individuals had a mean exposure of 6.2 m(2)-min/day. Differences in occupation led to males having much higher mean water exposures than females (9.2 v. 1.1 m(2)-min/day). As there was an inverse association between age-specific exposure and age-specific re-infection intensity, the marked reduction seen in intensity of re-infection with increasing age is not attributable to decreasing exposure to water. Instead, the results of this 2-year cohort study provide evidence for age-dependent resistance to re-infection with S. japonicum.The 213 subjects who were followed up were classified, according to epidemiological outcome at the end of the study and the data an water contact, as 'susceptible' (N = 49; 23%), 'insusceptible' (N = 29; 13.6%) or of 'uncertain status' (N = 135; 63.4%). Thus, 78 subjects who are potentially informative in terms of immunogenetics were identified. Further investigation of these individuals should help to shed some light on the role of immunogenetic status in human immunity to Schistosoma japonicum.