De Liberato Claudio, Berrilli Federica, Bossù Teresa, Magliano Adele, Montalbano Di Filippo Margherita, Di Cave David, Sigismondi Mariano, Cannavacciuolo Annunziata, Scaramozzino Paola
Istituto Zooprofilattico Sperimentale del Lazio e della Toscana "M. Aleandri", Rome, Italy.
Università di Roma Tor Vergata, Rome, Italy.
Zoonoses Public Health. 2019 Jun;66(4):377-381. doi: 10.1111/zph.12570. Epub 2019 Feb 19.
Swimmer's itch is caused by the penetration of free-swimming larvae of trematodes of the family Schistosomatidae in human skin. It is usually reported in people engaged in recreational water activities in freshwater bodies and in most of cases, it is provoked by bird schistosomes of the genus Trichobilharzia. In the summer 2017, many cases of dermatitis were recorded in people bathing in the waters of the Albano Lake (Rome, Italy) and a parasitological investigation was carried out in order to ascertain the causative agent of these cases. Snails of the family Lymnaeidae, natural intermediate hosts of bird schistosomes, were collected from lake shallow waters to detect the presence of trematodes of the genus Trichobilharzia. Pools of maximum 10 snails were placed in Petri dishes, and cercarial emergence was stimulated exposing snails to strong artificial light intensity at 25°C. Three hundred and thirty-seven snails were collected and screened for the shedding of cercariae. Furcocercariae of the family Schistosomatidae, with a morphology overlapping that of the genus Trichobilharzia, were detected in seven Petri dishes. Assuming that in each positive Petri dish just one snail was shedding furcocercariae, the minimum infectious rate was 2.1%. Molecular analysis of furcocercariae allowed ascribing them to the species Trichobilharzia franki. Snails of the species Radix auricularia were identified as intermediate hosts of the parasite. This is the second record of T. franki causing cercarial dermatitis in Central Italy, the third in Italy. The 2017 was in Italy exceptionally warm and dry. Trematodes are sensitive to changes in temperature, being cercarial production and emission rates temperature dependent. Small increases in water temperature would speed up parasite development and transmission, leading to a manifold increase in cercarial emergence. Moreover, high temperatures raise chances to acquire the infection, due to increased time spent in water by people.
尾蚴性皮炎是由裂体科吸虫的自由游动幼虫侵入人体皮肤引起的。通常在参与淡水水体娱乐性水上活动的人群中出现，在大多数情况下，是由毛毕属鸟类血吸虫引发的。2017年夏季，在意大利罗马阿尔巴诺湖水域游泳的人群中记录到多例皮炎病例，并开展了寄生虫学调查以确定这些病例的病原体。从湖浅水区采集了椎实螺科的蜗牛，它们是鸟类血吸虫的天然中间宿主，用于检测毛毕属吸虫的存在。将最多10只蜗牛放在培养皿中，通过在25°C下用强光照射刺激尾蚴逸出。共采集了337只蜗牛并筛查尾蚴逸出情况。在7个培养皿中检测到了裂体科的叉尾尾蚴，其形态与毛毕属吸虫重叠。假设每个阳性培养皿中只有一只蜗牛在释放叉尾尾蚴，最低感染率为2.1%。对叉尾尾蚴的分子分析确定其为弗兰克毛毕吸虫。耳萝卜螺被确定为该寄生虫的中间宿主。这是弗兰克毛毕吸虫在意大利中部导致尾蚴性皮炎的第二次记录，在意大利是第三次。2017年意大利异常温暖干燥。吸虫对温度变化敏感，尾蚴的产生和释放速率取决于温度。水温的小幅升高会加速寄生虫的发育和传播，导致尾蚴逸出数量大幅增加。此外，由于人们在水中停留时间增加，高温增加了感染的机会。
