Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, King's Buildings, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, Scotland EH9 3FL, UK.
Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, Scotland EH9 3FL, UK.
Prev Vet Med. 2024 Sep;230:106297. doi: 10.1016/j.prevetmed.2024.106297. Epub 2024 Aug 2.
The relative importance of maternal and horizontal transmission of small ruminant lentivirus (SRLV), the causative organism in maedi-visna, is poorly understood. Review of the literature shows that maternal transmission is inefficient, infecting only about 10-25 % of the lambs of infected ewes. Theory proves that maternal transmission alone cannot achieve the rates of transmission that would be required to start or maintain an outbreak. Maternal and horizontal transmission are additive in effect, and we use modelling to show that maternal transmission does not amplify or enhance prevalence in the presence of horizontal transmission. Taking steps to avoid maternal transmission by rearing lambs without infected maternal colostrum does have a role in producing a clean flock, but has no significance for the control of a disease outbreak if the conditions for horizontal transmission are present. Efforts to prevent disease by reducing the spread of SRLV must be focussed on minimising horizontal transmission.
小反刍动物慢病毒（SRLV）是绵羊肺腺瘤病和传染性鼻气管炎的病原体，其母源和水平传播的相对重要性尚不清楚。文献回顾表明，母源传播效率低下，仅感染约 10-25%的感染母羊所产羔羊。理论证明，仅母源传播本身不可能达到开始或维持暴发所需的传播率。母源传播和水平传播的效果是累加的，我们通过建模表明，在存在水平传播的情况下，母源传播不会放大或增加流行率。通过用不含有感染性初乳的羔羊来饲养以避免母源传播，这在产生无病羊群方面确实有一定作用，但如果存在水平传播的条件，则对控制疾病暴发没有意义。通过减少 SRLV 的传播来预防疾病的努力必须集中于最大限度地减少水平传播。
