Blanco Guillermo, Frías Óscar, Pitarch Aida, Carrete Martina
Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC. José Gutiérrez Abascal 2, Madrid 28006, Spain.
Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Sevilla 41013, Spain.
Curr Zool. 2022 Mar 31;69(2):109-120. doi: 10.1093/cz/zoac025. eCollection 2023 Apr.
Anthropogenic stressors can favor the occurrence of noninfectious disease that can be worsened by the impact of opportunistic pathogens, making the epizootiology of environmental diseases difficult to unravel. The incidence and impact of oral lesions in nestlings of a facultative scavenger species, the black kite , were examined over seven breeding seasons in the highly degraded environment close to Madrid, Spain. We found an overall prevalence of 31% of nestlings with oral lesions, with no clear spatial pattern in nests with affected and unaffected individuals. The occurrence and number of oral lesions were negatively associated with nestling body condition and brood size. Broods, where all siblings had oral lesions, were smaller than those where some or all siblings were apparently healthy, suggesting that oral disease could be causing nestling mortality and, consequently, brood size reduction. In turn, nestling body condition was negatively affected by lesion occurrence, brood size, and laying date. Although these relationships were bidirectional, piecewise structural equation modeling analyses showed a greater negative effect of body condition on lesion occurrence than vice versa, indicating that nestlings in poorer body condition were more likely to develop oral lesions (which could contribute to aggravate their state of deterioration) than those in better condition. Nestlings from small broods were also more likely to have oral disease (directly or indirectly through their lower body condition) than nestlings from large broods. Nestlings that hatched last in the broods showed greater development stress than those that hatched first. Anthropogenic stressors could trigger poor body condition, and contribute to microbiota dysbiosis-related diseases. Although further research is needed to determine the consequences for the long-term fitness of individuals, actions should be taken to mitigate adverse conditions that may favor the appearance of environmental diseases associated with peri-urban areas, given their rapid expansion over natural areas.
人为压力源可能促使非传染性疾病的发生，而机会性病原体的影响可能会使这些疾病恶化，这使得环境疾病的动物流行病学难以厘清。在西班牙马德里附近高度退化的环境中，我们对兼性食腐动物黑鸢雏鸟口腔病变的发病率及其影响进行了七个繁殖季节的研究。我们发现，总体上31%的雏鸟有口腔病变，受影响和未受影响个体的巢穴没有明显的空间分布模式。口腔病变的发生和数量与雏鸟的身体状况和窝雏数呈负相关。所有兄弟姐妹都有口腔病变的窝雏比一些或所有兄弟姐妹明显健康的窝雏要小，这表明口腔疾病可能导致雏鸟死亡，进而导致窝雏数减少。反过来，雏鸟的身体状况受到病变发生、窝雏数和产卵日期的负面影响。虽然这些关系是双向的，但分段结构方程模型分析表明，身体状况对病变发生的负面影响大于反之，这表明身体状况较差的雏鸟比状况较好的雏鸟更有可能出现口腔病变（这可能会加剧它们的恶化状态）。小窝雏的雏鸟也比大窝雏的雏鸟更有可能患口腔疾病（直接或通过其较低的身体状况间接导致）。在一窝雏鸟中最后孵化的雏鸟比最先孵化的雏鸟表现出更大的发育压力。人为压力源可能引发身体状况不佳，并导致与微生物群失调相关的疾病。尽管需要进一步研究以确定对个体长期健康的影响，但鉴于城市周边地区在自然区域的迅速扩张，应采取行动减轻可能有利于与城市周边地区相关的环境疾病出现的不利条件。
