Chastagner Amélie, Dugat Thibaud, Vourc'h Gwenaël, Verheyden Hélène, Legrand Loïc, Bachy Véronique, Chabanne Luc, Joncour Guy, Maillard Renaud, Boulouis Henri-Jean, Haddad Nadia, Bailly Xavier, Leblond Agnès
INRA, UR346 Epidémiologie Animale, F-63122, Saint Genès Champanelle, France.
Université Paris-Est, Ecole Nationale Vétérinaire d'Alfort, UMR BIPAR, 23 avenue du Général de Gaulle, 94706, Maisons-Alfort, France.
Vet Res. 2014 Dec 9;45:114. doi: 10.1186/s13567-014-0114-7.
Molecular epidemiology represents a powerful approach to elucidate the complex epidemiological cycles of multi-host pathogens, such as Anaplasma phagocytophilum. A. phagocytophilum is a tick-borne bacterium that affects a wide range of wild and domesticated animals. Here, we characterized its genetic diversity in populations of French cattle; we then compared the observed genotypes with those found in horses, dogs, and roe deer to determine whether genotypes of A. phagocytophilum are shared among different hosts. We sampled 120 domesticated animals (104 cattle, 13 horses, and 3 dogs) and 40 wild animals (roe deer) and used multilocus sequence analysis on nine loci (ankA, msp4, groESL, typA, pled, gyrA, recG, polA, and an intergenic region) to characterize the genotypes of A. phagocytophilum present. Phylogenic analysis revealed three genetic clusters of bacterial variants in domesticated animals. The two principal clusters included 98% of the bacterial genotypes found in cattle, which were only distantly related to those in roe deer. One cluster comprised only cattle genotypes, while the second contained genotypes from cattle, horses, and dogs. The third contained all roe deer genotypes and three cattle genotypes. Geographical factors could not explain this clustering pattern. These results suggest that roe deer do not contribute to the spread of A. phagocytophilum in cattle in France. Further studies should explore if these different clusters are associated with differing disease severity in domesticated hosts. Additionally, it remains to be seen if the three clusters of A. phagocytophilum genotypes in cattle correspond to distinct epidemiological cycles, potentially involving different reservoir hosts.
分子流行病学是阐明多宿主病原体（如嗜吞噬细胞无形体）复杂流行病学循环的有力方法。嗜吞噬细胞无形体是一种蜱传播细菌，可感染多种野生动物和家畜。在此，我们对法国牛群中的嗜吞噬细胞无形体进行了遗传多样性特征分析；然后将观察到的基因型与在马、狗和狍中发现的基因型进行比较，以确定嗜吞噬细胞无形体的基因型是否在不同宿主之间共享。我们对120只家畜（104头牛、13匹马和3只狗）和40只野生动物（狍）进行了采样，并对九个基因座（ankA、msp4、groESL、typA、pled、gyrA、recG、polA和一个基因间区域）进行多位点序列分析，以表征所存在的嗜吞噬细胞无形体的基因型。系统发育分析揭示了家畜中细菌变体的三个遗传簇。两个主要簇包含了牛中发现的98%的细菌基因型，这些基因型与狍中的基因型只有远缘关系。一个簇仅包含牛的基因型，而第二个簇包含来自牛、马和狗的基因型。第三个簇包含所有狍的基因型和三个牛的基因型。地理因素无法解释这种聚类模式。这些结果表明，狍对法国牛群中嗜吞噬细胞无形体的传播没有贡献。进一步的研究应探索这些不同的簇是否与家畜宿主中不同的疾病严重程度相关。此外，牛中嗜吞噬细胞无形体基因型的三个簇是否对应于不同的流行病学循环，可能涉及不同的储存宿主，还有待观察。
