Heukelbach Jörg, Feldmeier Hermann
Mandacaru Foundation and Department of Community Medicine, Federal University of Ceará State, Fortaleza, Brazil.
Lancet. 2004 Mar 13;363(9412):889-91. doi: 10.1016/S0140-6736(04)15738-3.
Ectoparasitoses (infestations with parasites that live on or in the skin) can cause considerable morbidity. Whereas pediculosis and scabies are ubiquitous, cutaneous larva migrans and tungiasis (sand-flea disease) occur mainly in hot climates. The prevalence of ectoparasitoses in the general population is usually low, but can be high in vulnerable groups. Scientific knowledge on how to deal best with parasitic skin diseases in different settings is scanty, and evidence-based measures for control are not available. For head lice and scabies the situation is daunting, because resistance of Pediculus humanus capitis and Sarcoptes scabiei to insecticides is spreading and unpredictable.
J Hunter and S Barker reported different patterns of resistance in schoolchildren in Brisbane, Australia: full resistance to malathion, permethrin, and pyrethrum in two schools, whereas head lice were susceptible to malathion and, to a lesser extent, to pyrethrums in three other schools (Parasitol Res 2003; 90: 476-78). K Yoon and colleagues found different resistance patterns in the USA and Ecuador (Arch Dermatol 2003; 139: 994-1000). Head lice from Florida were less susceptible to permethrin than those from Texas, and parasites from Ecuador were susceptible to both insecticides tested. WHERE NEXT? The occurrence of resistant pediculosis and scabies is expected to increase numerically and geographically. Clinicoepidemiological studies are urgently needed to identify the factors which govern the emergence and spread of strains of P humanus capitis and S scabiei that are resistant to insecticide or acaricide. Oral treatment with ivermectin could substitute for topically applied compounds, particularly in resource-poor communities where polyparasitism is common. A better understanding of local epidemiology is required to develop control measures. This knowledge has to be applied in combination with environmental sanitation, health education, and culturally acceptable interventions that are affordable by the underprivileged.
体外寄生虫病（由寄生于皮肤表面或皮肤内的寄生虫引起的感染）可导致相当大的发病率。头虱病和疥疮随处可见，而皮肤幼虫移行症和潜蚤病（沙蚤病）主要发生在炎热气候地区。一般人群中体外寄生虫病的患病率通常较低，但在弱势群体中可能较高。关于如何在不同环境中最佳应对寄生虫性皮肤病的科学知识匮乏，且缺乏基于证据的控制措施。对于头虱和疥疮而言，情况令人担忧，因为人头虱和疥螨对杀虫剂的耐药性正在蔓延且难以预测。
J·亨特和S·巴克报道了澳大利亚布里斯班学童的不同耐药模式：在两所学校中，对头虱对马拉硫磷、氯菊酯和除虫菊完全耐药，而在另外三所学校中，头虱对马拉硫磷敏感，对除虫菊的敏感性稍低（《寄生虫病研究》2003年；90: 476 - 78）。K·尹及其同事在美国和厄瓜多尔发现了不同的耐药模式（《皮肤病学文献》2003年；139: 994 - 1000）。来自佛罗里达的数据头虱对氯菊酯的敏感性低于来自得克萨斯的头虱，而来自厄瓜多尔的寄生虫对所测试的两种杀虫剂均敏感。
下一步走向何方？预计耐药性头虱病和疥疮在数量和地理范围上都会增加。迫切需要开展临床流行病学研究，以确定导致人头虱和疥螨对杀虫剂或杀螨剂产生耐药菌株出现和传播的因素。伊维菌素口服治疗可替代局部应用的化合物，特别是在多寄生虫感染常见的资源匮乏社区。需要更好地了解当地流行病学以制定控制措施。必须将这些知识与环境卫生、健康教育以及弱势群体能够负担得起的文化上可接受的干预措施相结合应用。
