West Nile Virus Lineage 2 Strain in Greece, 2012

The low diversity we found could be explained by a recent introduction of the bacteria into the area [although A. phagocytophilum–seropositive horses have been found in the area since 2001 (3)] or by a selective sweep linked to the particular ticks and host reservoir in Camargue. The 5 species of ticks that we found positive for A. phagocytophilum have been described as potential vectors of A. phagocytophilum in the Mediterranean Basin (2,10). Among the tick species in our investigation, R. bursa and R. sanguineus ticks are the 2 main carriers of A. phagocytophilum, and these ticks are likely to feed on humans and, thus, pose a risk of infection to the local population. Further studies are needed to address the potential effect of A. phagocytophilum–infected ticks on human health in this area and, more specifically, the relationship between genotype and pathogenicity.