Risk factors and coinfection dynamics of pathogens in wild turkeys (<em>Meleagris gallopavo</em>) from Pennsylvania, USA

Interactions between co-occurring pathogens can have complex and significant impacts on host survival, fitness, and population dynamics. While common in wildlife, coinfections are often overlooked, and research may create biased management perspectives when individual pathogens are assessed in isolation. Recent work has found that wild turkeys (Meleagris gallopavo) are affected by various pathogens, but it is unknown how infections and coinfections are spatially structured or interact with each other. Here, we determined the associations and risk factors of infection by lymphoproliferative disease virus (LPDV), reticuloendotheliosis virus (REV), three avian Mycoplasma species, and internal parasites in Pennsylvania wild turkeys. Our results indicate varying prevalences: LPDV (70%), REV (1%), Mycoplasma gallisepticum (0%), Mycoplasma meleagridis (4%), Mycoplasma synoviae (2%), and internal parasites (63%). The prevalence of LPDV was greater in adults than juveniles but did not vary with year, sex, study area, or landscape type. Parasite species richness was greater in juveniles than adults, greater in males than females, varied by year and study area, but did not vary with landscape type. Coinfections with LPDV and parasites were more common (41%) than infections with only LPDV (26%) or only parasites (22%). All other coinfection prevalences involving viruses, Mycoplasma species, and parasites were low (0–3%). Finally, infection with LPDV did not differ with overall parasite species richness but was negatively associated with infection with parasitic nematodes. These results reveal high rates of coinfections with LPDV and parasites in turkeys but suggest that parasite infections are independent of LPDV infections. Ongoing work is currently investigating the sublethal effects of these coinfections on wild turkey populations.共栖病原体间的相互作用可对宿主存活、适合度（fitness）及种群动态产生复杂且显著的影响。尽管混合感染在野生动物种群中十分常见，但此类感染常被忽视；若仅针对单一病原体开展研究，相关成果可能会形成带有偏差的管理认知。 既往研究发现，野火鸡（Meleagris gallopavo）会受到多种病原体的侵染，但目前尚不明确其感染与混合感染的空间分布格局，亦不清楚各类病原体间的相互作用模式。本研究针对宾夕法尼亚州的野火鸡，明确了其感染淋巴细胞增生性疾病病毒（LPDV）、网状内皮组织增生症病毒（REV）、三种禽支原体及体内寄生虫的关联特征与风险因子。 研究结果显示各类病原体的感染率存在显著差异：LPDV为70%，REV为1%，鸡毒支原体（Mycoplasma gallisepticum）为0%，火鸡支原体（Mycoplasma meleagridis）为4%，滑膜支原体（Mycoplasma synoviae）为2%，体内寄生虫为63%。其中，LPDV的感染率在成体中显著高于幼体，但未随年份、性别、研究区域或景观类型发生变化。寄生虫物种丰富度在幼体中高于成体，雄性个体高于雌性个体，且随年份与研究区域发生变化，但与景观类型无关。 LPDV与体内寄生虫的混合感染占比（41%）高于仅感染LPDV（26%）或仅感染体内寄生虫（22%）的情况。其余涉及病毒、禽支原体与寄生虫的混合感染占比均较低（0%~3%）。此外，LPDV感染与整体寄生虫物种丰富度无显著关联，但与寄生线虫（parasitic nematodes）感染呈负相关关系。 本研究结果揭示了野火鸡中LPDV与体内寄生虫的高混合感染率，但同时表明寄生虫感染与LPDV感染相互独立。目前相关后续研究正针对此类混合感染对野火鸡种群的亚致死效应展开探究。