Amaya-Mejia Wilmer, Pavan Lucas, Lilly Marie, Swei Andrea, Dirzo Rodolfo, Sehgal Ravinder N M
University of California, Los Angeles, California, USA.
San Francisco State University, San Francisco, California, USA.
Parasit Vectors. 2025 Mar 15;18(1):110. doi: 10.1186/s13071-025-06742-x.
As habitat fragmentation increases, ecological processes, including patterns of vector-borne pathogen prevalence, will likely be disrupted, but ongoing investigations are necessary to examine this relationship. Here, we report the differences in the prevalence of Lyme disease (Borrelia burgdorferi sensu lato, s.l.) and haemoproteosis (Haemoproteus spp.) pathogens in avian populations of a fragmented habitat. B. burgdorferi s.l. is a generalist pathogen that is transmitted by Ixodes pacificus vectors in California, and Haemoproteus is an avian parasite transmitted by Culicoides vectors.
To determine whether biotic (avian and mammalian abundance) or abiotic characteristics (patch size and water availability) correlated with infection prevalence change, we screened 176 birds sampled across seven sites in oak woodland habitat in northern California.
While biotic factors correlated with an increase in both pathogens, infection prevalence of Haemoproteus spp. was only associated with individual-level traits, specifically foraging substrate and diet, and B. burgdorferi s.l. was associated with community-level characteristics, both total mammal and, specifically, rodent abundance. Proximity to water was the only abiotic factor found to be significant for both pathogens and reinforces the importance of water availability for transmission cycles. Larger patch sizes did not significantly affect infection prevalence of Haemoproteus, but did increase the prevalence of B. burgdorferi.
These results highlight that while environmental factors (specifically habitat fragmentation) have a limited role in vector-borne pathogen prevalence, the indirect impact to biotic factors (community composition) can have consequences for both Haemoproteus and B. burgdorferi prevalence in birds. Given the pervasiveness of habitat fragmentation, our results are of broad significance.
随着栖息地破碎化加剧，包括媒介传播病原体流行模式在内的生态过程可能会受到干扰，但仍需进行持续调查以研究这种关系。在此，我们报告了碎片化栖息地鸟类种群中莱姆病（广义伯氏疏螺旋体）和血孢子虫病（血孢子虫属）病原体流行率的差异。广义伯氏疏螺旋体是一种多宿主病原体，在加利福尼亚由太平洋硬蜱传播，而血孢子虫是一种由库蠓传播的鸟类寄生虫。
为了确定生物因素（鸟类和哺乳动物数量）或非生物特征（斑块大小和水源可利用性）是否与感染流行率变化相关，我们对在加利福尼亚北部橡树林栖息地七个地点采集的176只鸟类进行了筛查。
虽然生物因素与两种病原体的增加都相关，但血孢子虫属的感染流行率仅与个体水平特征相关，特别是觅食基质和饮食，而广义伯氏疏螺旋体与群落水平特征相关，包括总哺乳动物数量，特别是啮齿动物数量。靠近水源是唯一对两种病原体都有显著影响的非生物因素，这强化了水源可利用性对传播循环的重要性。较大的斑块大小对血孢子虫的感染流行率没有显著影响，但确实增加了广义伯氏疏螺旋体的流行率。
这些结果表明，虽然环境因素（特别是栖息地破碎化）在媒介传播病原体流行率方面作用有限，但对生物因素（群落组成）的间接影响可能会对鸟类中血孢子虫和广义伯氏疏螺旋体的流行率产生影响。鉴于栖息地破碎化的普遍性，我们的结果具有广泛的意义。
