Geissler P W, Mwaniki D, Thiong F, Friis H
Danish Bilharziasis Laboratory, Charlottenlund, Denmark.
Trans R Soc Trop Med Hyg. 1998 Jan-Feb;92(1):7-11. doi: 10.1016/s0035-9203(98)90934-8.
Geophagy among primary schoolchildren and its impact on geohelminth infection were studied in western Kenya. In a cross-sectional survey, 204 children aged 10-18 years were interviewed about geophagy and examined for helminth infections (Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni, hookworm). Children found infected were treated with albendazole (600 mg in a single dose) and/or praziquantel (40 mg/kg in a single dose). The children were re-examined after 4, 8 and 11 months. In the initial cross-sectional survey, 77% of the children ate soil daily and 48% of all soil samples were contaminated with eggs of A. lumbricoides (median egg count in contaminated samples was 3/2 g of soil; range 1-15). Twenty-nine children (14.2%) were infected with A. lumbricoides and 87 (42.6%) with T. trichiura. Significant associations between geophagy and infection intensity with A. lumbricoides and T. trichiura, but not S. mansoni or hookworm, were found. Re-infection with A. lumbricoides was twice as common among geophagous children as among non-geophagous children (27.4% vs. 12.0%; P = 0.030). The intensity of reinfections was higher in geophagous children (median 773 eggs/g vs. 95 eggs/g; P = 0.027). The relative risk for A. lumbricoides reinfection was 2.28 for geophagous children (95% confidence interval [95% CI] 1.02-5.11), and the fraction of reinfection attributable to geophagy was 56.0% (95% CI 1.7%-80.4%). There was a significant difference in T. trichiura infection intensity between geophagous and non-geophagous children (median no. of eggs/g 68 vs. 20; P = 0.049), but not in reinfection rates. No difference between the groups was seen in S. mansoni or hookworm reinfection rate or intensity, or in the families' socioeconomic or educational status. Geophagy was associated with an increased risk of reinfection with A. lumbricoides and possibly with T. trichiura. Neither family background nor infection with non-orally transmitted helminths was associated with geophagy, suggesting that this association was not due to confounding, but causal. Geophagy is therefore likely to be a source of ascariasis and possibly trichiuriasis among primary schoolchildren.
在肯尼亚西部对小学生的食土癖及其对土源性蠕虫感染的影响进行了研究。在一项横断面调查中，对204名10 - 18岁的儿童进行了关于食土癖的访谈，并检查了蠕虫感染情况（蛔虫、鞭虫、曼氏血吸虫、钩虫）。发现感染的儿童用阿苯达唑（单次剂量600毫克）和/或吡喹酮（单次剂量40毫克/千克）进行治疗。在4、8和11个月后对儿童进行了复查。在最初的横断面调查中，77%的儿童每天吃土，所有土壤样本中有48%被蛔虫卵污染（污染样本中的蛔虫卵中位数为每2克土壤3个；范围为1 - 15个）。29名儿童（14.2%）感染了蛔虫，87名（42.6%）感染了鞭虫。发现食土癖与蛔虫和鞭虫的感染强度之间存在显著关联，但与曼氏血吸虫或钩虫无关。食土儿童蛔虫再次感染的发生率是非食土儿童的两倍（27.4%对12.0%；P = 0.030）。食土儿童再次感染的强度更高（中位数为每克773个卵对95个卵；P = 0.027）。食土儿童蛔虫再次感染的相对风险为2.28（95%置信区间[95%CI]1.02 - 5.11），归因于食土癖的再次感染比例为56.0%（95%CI 1.7% - 80.4%）。食土儿童和非食土儿童的鞭虫感染强度存在显著差异（每克虫卵中位数分别为68个和20个；P = 0.049），但再次感染率没有差异。在曼氏血吸虫或钩虫的再次感染率或强度以及家庭的社会经济或教育状况方面，两组之间没有差异。食土癖与蛔虫再次感染风险增加以及可能与鞭虫再次感染风险增加有关。家庭背景和非经口传播的蠕虫感染均与食土癖无关，这表明这种关联不是由于混杂因素，而是因果关系。因此，食土癖很可能是小学生蛔虫病和可能的鞭虫病的一个来源。
