据估计,全世界有超过2亿7百万人感染血吸虫。[3]Steinmann P, Keiser J, Bos R, et al. Schistosomiasis and water resources development: systematic review, meta-analysis, and estimates of people at risk. Lancet Infect Dis. 2006;6:411-425.http://www.ncbi.nlm.nih.gov/pubmed/16790382?tool=bestpractice.com大部分受感染者居住在撒哈拉以南非洲的农村和不发达地区。[4]van der Werf MJ, de Vlas SJ, Brooker S, et al. Quantification of clinical morbidity associated with schistosome infection in sub-Saharan Africa. Acta Trop. 2003;86:125-139.http://www.ncbi.nlm.nih.gov/pubmed/12745133?tool=bestpractice.com血吸虫感染通常发生在儿童时期。最易流行和感染的人群为学龄儿童,青少年和年轻人。[5]King CH. Epidemiology of schistosomiasis: determinants of transmission of infection. In: Mahmoud AAF, ed. Schistosomiasis. London, UK: Imperial College Press; 2001:115-132.
血吸虫和宿主可协同进化。5种血吸虫能感染人类,但其他血吸虫可以感染特定动物或中间宿主螺。在美国,只有尾蚴性皮炎这一种地方性血吸虫病,它是由鸟吸虫污染北部湖泊后引起的。其与暂时性皮肤瘙痒病变有关,但与全身表现或终末器官损伤无关。在美国,鸟吸虫的尾蚴通过中间宿主螺释放到人类游泳的水中。在这种尾蚴进入人体皮肤后,鸟吸虫不能完成它的生活史从而不能引起人类其他疾病。[6]King CH. Disease due to Schistosoma mekongi, S intercalatum and other Schistosome species. In: Mahmoud AAF, ed. Schistosomiasis. London, UK: Imperial College Press; 2001:391-412.[7]Lindblade KA. The epidemiology of cercarial dermatitis and its association with limnological characteristics of a northern Michigan lake. J Parasitol. 1998;84:19-23.http://www.ncbi.nlm.nih.gov/pubmed/9488332?tool=bestpractice.com
在美国,所有急性或慢性血吸虫病病例均来自于从流行国家归来的旅行者或移民输入。[8]Centers for Disease Control and Prevention. November 2012. Parasites - schistosomiasis. http://www.cdc.gov/ (last accessed 5 December 2016).http://www.cdc.gov/parasites/schistosomiasis/在法国科西嘉,已有血吸虫病的报告,可能由移民引入寄生虫所致。大部分受感染者居住在撒哈拉以南非洲的农村和不发达地区。[4]van der Werf MJ, de Vlas SJ, Brooker S, et al. Quantification of clinical morbidity associated with schistosome infection in sub-Saharan Africa. Acta Trop. 2003;86:125-139.http://www.ncbi.nlm.nih.gov/pubmed/12745133?tool=bestpractice.com血吸虫感染通常发生在儿童时期。最易流行和感染的人群为学龄儿童,青少年和年轻人。[5]King CH. Epidemiology of schistosomiasis: determinants of transmission of infection. In: Mahmoud AAF, ed. Schistosomiasis. London, UK: Imperial College Press; 2001:115-132.
血吸虫地理分布取决于中间宿主螺的范围。[2]Sturrock RF. The schistosomes and their intermediate hosts. In: Mahmoud AAF, ed. Schistosomiasis. London, UK: Imperial College Press; 2001:7-83.