The penetration of Trichobilharzia ocellata cercariae into the skin of their duck hosts was described using electron microscopy and histology. The behavior patterns of the cercariae on their exposure to human skin differed only little from those known for Schistosoma mansoni cercariae. After their attachment to living human skin the cercariae crept to wrinkles within a mean of 8 s, and full penetration was achieved within a mean of 4.0 min (83 s to 13.3 min). Tail shedding occurred as early as within a mean of 6.5 s of the first penetration attempts. It was supported by a muscular sphincter at the cercarial hindbody. The skin-surface stimuli for cercarial penetration were contained in the lipid fraction of the duck and human skin surface; hydrophilic components were effective only in some T. ocellata isolates. The penetration-stimulating components of duck-skin lipids were exclusively free fatty acids with the same chemical characteristics known to stimulate penetration of Schistosoma species. Skin-surface lipids of the abnormal human host, with their higher fatty acid contents, stimulated higher cercarial penetration rates than did skin lipids of the natural duck host. Fatty acids as penetration stimuli may offer advantages for T. ocellata cercariae by increasing the specificity for an invasion of terrestrial vertebrates, which is additionally determined by cholesterol and ceramides as signals for attachment and enduring contact behavior.

BackgroundPresentation of confidence intervals alongside information about treatment effects can support informed treatment choices in people with multiple sclerosis.We aimed to develop and pilot-test different written patient information materials explaining confidence intervals in people with relapsing-remitting multiple sclerosis. Further, a questionnaire on comprehension of confidence intervals was developed and piloted.MethodsWe developed different patient information versions aiming to explain confidence intervals. We used an illustrative example to test three different approaches: (1) short version, (2) “average weight” version and (3) “worm prophylaxis” version. Interviews were conducted using think-aloud and teach-back approaches to test feasibility and analysed using qualitative content analysis. To assess comprehension of confidence intervals, a six-item multiple choice questionnaire was developed and tested in a pilot randomised controlled trial using the online survey software UNIPARK. Here, the average weight version (intervention group) was tested against a standard patient information version on confidence intervals (control group). People with multiple sclerosis were invited to take part using existing mailing-lists of people with multiple sclerosis in Germany and were randomised using the UNIPARK algorithm. Participants were blinded towards group allocation. Primary endpoint was comprehension of confidence intervals, assessed with the six-item multiple choice questionnaire with six points representing perfect knowledge.ResultsFeasibility of the patient information versions was tested with 16 people with multiple sclerosis. For the pilot randomised controlled trial, 64 people with multiple sclerosis were randomised (intervention group: n = 36; control group: n = 28). More questions were answered correctly in the intervention group compared to the control group (mean 4.8 vs 3.8, mean difference 1.1 (95 % CI 0.42–1.69), p = 0.002). The questionnaire’s internal consistency was moderate (Cronbach's alpha = 0.56).ConclusionsThe pilot-phase shows promising results concerning acceptability and feasibility. Pilot randomised controlled trial results indicate that the patient information is well understood and that knowledge gain on confidence intervals can be assessed with a set of six questions.Trial registrationGerman Clinical Trials Register: DRKS00008561. Registered 8th of June 2015.Electronic supplementary materialThe online version of this article (doi:10.1186/s12911-016-0362-8) contains supplementary material, which is available to authorized users.

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