Data from: Apparent vector-mediated parent-to-offspring transmission in an avian malaria-like parasite

Parasite transmission strategies strongly impact host-parasite coevolution and virulence. However, studies of vector-borne parasites such as avian malaria have neglected the potential effects of host relatedness on the exchange of parasites. To test whether extended parental care in the presence of vectors increases the probability of transmission from parents to offspring, we used high-throughput sequencing to develop microsatellites for malaria-like Leucocytozoon parasites of a wild raptor population. We show that host siblings carry genetically more similar parasites than unrelated chicks both within and across years. Moreover, chicks of mothers of the same plumage morph carried more similar parasite infections than nestlings whose mothers were of different morphs, consistent with matrilineal transmission of morph-specific parasite strains. Ours is the first evidence of an association between host relatedness and parasite genetic similarity, consistent with vector-mediated parent-to-offspring transmission. The conditions for such 'quasi-vertical' transmission may be common and could suppress the evolution of pathogen virulence.

寄生虫的传播策略对宿主-寄生虫协同进化及病原体毒力具有显著影响。然而，针对禽疟疾这类虫媒寄生虫的相关研究，往往忽视了宿主亲缘关系对寄生虫交换的潜在作用。为验证在虫媒存在的前提下，延长双亲抚育行为是否会提升寄生虫从亲本向子代传播的概率，我们借助高通量测序（High-throughput sequencing）技术，为某野生猛禽种群中的类疟疾住白细胞虫（Leucocytozoon）开发了微卫星标记（microsatellites）。研究结果表明，无论在同年度还是跨年度样本中，宿主同胞携带的寄生虫遗传相似性均显著高于无亲缘关系的幼雏。此外，母体羽色形态相同的幼雏，其寄生虫感染的遗传相似性显著高于母体羽色形态不同的幼雏，这与羽色特异性寄生虫毒株的母系传播模式一致。本研究首次证实宿主亲缘关系与寄生虫遗传相似性之间存在关联，且该结果与虫媒介导的亲本向子代传播模式相符。这类‘准垂直传播’的发生条件或较为普遍，且有望抑制病原体毒力的进化。