Caron Yannick, Cabaraux Ariane, Marechal Françoise, Losson Bertrand
1 Research Unit in Parasitology and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège , Liège, Belgium .
2 Environment and Security Unit, Les Lacs de l'Eau d'Heure (Non-Profit Making Association), Boussu-Lez-Walcourt, Belgium .
Vector Borne Zoonotic Dis. 2017 Mar;17(3):190-194. doi: 10.1089/vbz.2016.2034. Epub 2017 Jan 23.
Cercarial dermatitis or swimmer's itch is a skin condition in humans due to the larval forms of bird schistosomes of some species of the genus Trichobilharzia. The life cycle of these schistosomes requires freshwater snails (intermediate host) and waterfowl (definitive host). Repeated exposures to cercariae can lead to skin sensitization with the induction of pruritic skin lesions.
We describe, in this study, two outbreaks of human cercarial dermatitis at the Eau d'Heure Lakes, Belgium. In July and August 2012, a total of, respectively, 78 and 10 people reported a sudden skin rash accompanied by pruritus following recreational activities in the Plate Taille Lake. However, no ocellate furcocercariae were detected following light exposure of the snails collected between September 2012 and September 2013 (n = 402). No outbreaks were recorded in 2013 and 2014. In August 2015, about 30 new cases were recorded. Snails were collected (n = 270) in different locations around the lake. PCR was used to identify accurately the intermediate hosts and the parasite species involved.
After light exposure, seven Radix spp. (2.6%) shed ocellate furcocercariae. Molecular identification based on the rDNA internal transcribed spacer 2 sequence ascribed the infected snails to R. balthica ( = R. peregra = R. ovata) (6/7) and R. auricularia (1/7). Based on the amplification of the D2 domain of the 28S rDNA, the cercariae were shown to belong to two different haplotypes of Trichobilharzia franki.
This is the first record in Belgium of T. franki and associated skin condition.
尾蚴性皮炎或游泳者瘙痒症是人类因毛毕属某些物种的鸟类血吸虫幼虫形态引起的一种皮肤疾病。这些血吸虫的生命周期需要淡水螺（中间宿主）和水禽（终宿主）。反复接触尾蚴可导致皮肤致敏并引发瘙痒性皮肤病变。
在本研究中，我们描述了比利时埃勒湖发生的两起人类尾蚴性皮炎疫情。2012年7月和8月，分别有78人和10人报告在塔伊勒湖进行娱乐活动后突然出现皮疹并伴有瘙痒。然而，在2012年9月至2013年9月期间采集的蜗牛（n = 402）经光照后未检测到有眼点叉尾蚴。2013年和2014年未记录到疫情。2015年8月，记录到约30例新病例。在湖周围不同地点采集了蜗牛（n = 270）。采用聚合酶链反应准确鉴定中间宿主和相关寄生虫种类。
光照后，7只椎实螺属蜗牛（2.6%）排出有眼点叉尾蚴。基于核糖体DNA内转录间隔区2序列的分子鉴定将受感染的蜗牛归为卵形椎实螺（= 静水椎实螺 = 椭圆萝卜螺）（6/7）和耳萝卜螺（1/7）。基于28S核糖体DNA D2结构域的扩增，尾蚴显示属于弗兰克毛毕吸虫的两种不同单倍型。
这是比利时首次记录到弗兰克毛毕吸虫及相关皮肤疾病。
