CIBIO-UP, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal,
Parasitol Res. 2013 Dec;112(12):4001-7. doi: 10.1007/s00436-013-3588-8. Epub 2013 Sep 3.
Parasitological analyses are often based on invasive methodologies, involving host sacrifice, raising ethical and conservation issues. However, alternative non-invasive approaches may not be always applicable due to the location of the parasite in the host tissue or the quality and reliability of the non-invasive sample per se. In this study, we compare the differences in detectability of intestinal parasites in reptiles using the classical invasive approach (intestine dissection), versus a non-invasive procedure (faecal examination), collected from the same individual host. Our results showed significantly lower detectability of helminths in faeces versus the intestine. Moreover, the number of parasites found in faeces was not explained either by the intensities found in the respective intestine or by the host identity. Several factors may explain the lack of association between the two types of samples, but more importantly, our results highlight the randomness of the presence of parasites in faeces. Even if it is not recommended that comparative studies of either parasite abundance or parasite communities be conducted on the basis of faecal samples, there are other types of studies (i.e. genetic) that can be performed with this source of information, thus avoiding the sacrifice of the host. Due to their wide spectrum of life stages and localization in the host tissue, parasites are challenging candidates for non-invasive sampling and consequently, parasitological methodologies should be carefully selected according to the objective of the study.
寄生虫学分析通常基于侵袭性方法，涉及宿主牺牲，引发伦理和保护问题。然而，由于寄生虫在宿主组织中的位置，或者非侵入性样本本身的质量和可靠性，替代的非侵入性方法并不总是适用。在这项研究中，我们比较了使用经典的侵袭性方法（肠道解剖）和非侵袭性方法（粪便检查）检测爬行动物肠道寄生虫的差异，这些方法均来自同一宿主个体。我们的结果表明，粪便中寄生虫的检测率明显低于肠道。此外，粪便中发现的寄生虫数量既不能用相应肠道中的强度来解释，也不能用宿主身份来解释。有几个因素可以解释这两种类型的样本之间缺乏关联，但更重要的是，我们的结果强调了寄生虫在粪便中存在的随机性。即使不建议基于粪便样本进行寄生虫丰度或寄生虫群落的比较研究，但仍可以使用这种信息来源进行其他类型的研究（例如遗传学），从而避免宿主的牺牲。由于寄生虫在宿主组织中的生活阶段广泛且定位多样，因此对于非侵入性采样来说是一个挑战，因此，寄生虫学方法应根据研究目的进行仔细选择。
