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Abstract：
Prevalence responses to anthropic factors differ across hosts and parasite species. We here analyzed the spatiotemporal variation of avian haemosporidian prevalence in bird assemblages of the Mooswald forest (i.e., urban greenspace; Freiburg, Germany), in response to local environmental features (e.g., water sources, human presence (visited)/absence (unvisited)) and bird-level traits (e.g., body condition, age, sex) in 2 years. We used a nested PCR protocol (mitochondrial (mt)DNA cytochrome b (cyt b) gene) and microscopy to determine haemosporidian infections. Prevalence was analyzed using a general linear multi-model (glmulti) approach with Akaike information criterion corrected for small samples (AICc), with subsequent model inferences using a GLMM on the best selected model, considering bird species as a random factor. Analyses were conducted for the main understory bird species (Blackcap - Sylvia atricapilla, Chaffinch - Coereba flaveola, Great Tit - Parus major, Blue Tit - Cyanistes caeruleus, European Robin - Erithacus rubecula, Blackbird - Turdus merula, Song Thrush - Turdus philomelos). We further conducted spatial autocorrelation analyses for all haemosporidian infections, and classification and regression trees (CARTs) for focal species. We analyzed a total of 544 samples of seven bird species. In 2011 prevalence for Haemoproteus/Plasmodium was 25.8% and 11.7% for Leucocytozoon. In 2013 prevalence for Haemoproteus/Plasmodium was 26.5% and 35.5% for Leucocytozoon. Haemosporidian prevalence was significantly different between some focal species. There was a negative association between distance to the nearest water source and prevalence in the year 2011, and the opposite pattern for the year 2013. However, when analyzed for the six focal species separately, such a relationship could change from a negative to a positive one, or there could be no relationship at all. For Leucocytozoon there was higher prevalence in the section of the forest visited by humans. We did not find spatial autocorrelation for prevalence across the study site, but there were statistically significant local spatial clusters in the visited section. Although there were similar responses of prevalence to some factors, infection patterns were generally bird species-specific. Thus, prevalence is a labile epidemiological parameter, varying spatiotemporally in an idiosyncratic way.
摘要：
对人类因素的流行反应在宿主和寄生虫物种之间有所不同。我们在这里分析了Mooswald森林鸟类组合中鸟类血吸虫患病率的时空变化（即，城市绿地；弗莱堡，德国),响应当地环境特征(例如，水源,人类存在(访问)/不存在(未访问))和鸟类水平特征(例如，身体状况,年龄,性）在2年内。我们使用巢式PCR方案（线粒体（mt）DNA细胞色素b（cytb）基因）和显微镜检查来确定血孢子虫感染。使用一般线性多模型（glmulti）方法分析患病率，并对小样本（AICc）校正Akaike信息准则，随后在最佳选择的模型上使用GLMM进行模型推断，将鸟类物种视为随机因素。对主要的林下鸟类物种(Blackcap-Sylviaatricapilla，Chaffinch-Coerebaflaveola，大山雀-Parus少校，蓝色山雀-仙人掌，欧洲罗宾-艾尔塔克斯rubecula，黑鸟-Turdusmerula，SongThrush-Turdusphilomelos）。我们进一步对所有血孢子虫感染进行了空间自相关分析，以及重点物种的分类和回归树(CART)。我们共分析了7种鸟类的544个样本。2011年，变形杆菌/疟原虫的患病率分别为25.8%和11.7%。2013年，变形杆菌/疟原虫的患病率分别为26.5%和35.5%。在某些局灶性物种之间，血孢子虫的患病率显着不同。2011年，与最近水源的距离与患病率之间存在负相关关系，而2013年则相反。然而,当分别分析六个焦点物种时，这种关系可能会从消极转变为积极的关系，或者根本没有关系。对于白细胞，人类参观的森林区域的患病率更高。我们没有发现整个研究地点患病率的空间自相关，但是在访问的部分中存在统计上显著的局部空间集群。尽管对某些因素有类似的患病率反应，感染模式通常是鸟类特定的。因此，患病率是一个不稳定的流行病学参数，以特殊的方式时空变化。
