Tick–Host–Pathogen Interactions: Conflict and Cooperation

The Model Ticks are blood-feeding arthropod ectoparasites that transmit pathogens that constitute a growing burden for human and animal health worldwide [1-3].Only second to mosquitoes as vector of human diseases and the first vector of animal diseases, ticks transmit bacterial, parasitic, and viral pathogens [1].One of these pathogens is the intracellular bacterium Anaplasma phagocytophilum, which is vectored primarily by Ixodes tick species and is the causative agent of human granulocytic anaplasmosis (HGA), equine and canine granulocytic anaplasmosis, and tick-borne fever of ruminants [1].This pathogen is a good model because recent analysis of the molecular interactions between Ixodes tick vectors, A. phagocytophilum, and host cells showed pathogenic effects of both ticks and pathogens but also revealed the mutual beneficial effects of the tick-host-pathogen molecular interactions [4][5][6][7].