Department of Immunology and Infection, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Institut Pasteur, 25-28 rue du Dr Roux 75015, Paris, France.
Commun Biol. 2019 Feb 28;2:84. doi: 10.1038/s42003-019-0323-8. eCollection 2019.
Predicting how will respond to control efforts requires an understanding of their transmission strategy. Using real-time quantitative PCR to quantify infectious metacyclic and non-metacyclic forms in mouse skin from single sandfly bites we show that most transmissions were highly enriched for infectious parasites. However, a quarter of sandflies were capable of transmitting high doses containing more non-infectious promastigotes from the vector's midgut. Mouse infections replicating "high" to "low" quality, low-dose transmissions confirmed clear differences in the pathology of the infection and their onward transmissibility back to sandflies. Borrowing methods originally developed to account for exposure heterogeneity among hosts, we show how these high-dose, low-quality transmitters act as super-spreading vectors, capable of inflating transmission potential by as much as six-fold. These results highlight the hidden potential of transmission of mixed promastigote stages on disease prevalence and the role of dose heterogeneity as an underlying strategy for efficient transmission.
预测寄生虫将如何对控制措施作出反应需要了解其传播策略。我们利用实时定量 PCR 技术，对来自单次沙蝇叮咬的小鼠皮肤中的传染性前鞭毛体和非前鞭毛体进行定量，结果表明，大多数传播都高度富集了传染性寄生虫。然而，有四分之一的沙蝇能够从前肠中传递高剂量的非传染性前鞭毛体。复制“高”到“低”质量的小鼠感染、高剂量低质量的传播证实了感染的病理学和向沙蝇传播的后续能力有明显的差异。借鉴最初开发的用于解释宿主之间暴露异质性的方法，我们展示了这些高剂量低质量的传播者如何充当超级传播媒介，能够使传播潜力膨胀六倍。这些结果突出了混合前鞭毛体阶段传播对疾病流行的潜在影响，以及剂量异质性作为有效传播的潜在策略的作用。
