The natural history of Anaplasma phagocytophilum

摘要: Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, equi and agent human ehrlichiosis, after recent reorganization families Rickettsiaceae Anaplasmataceae in order Rickettsiales. Tick-borne fever (TBF), which caused by prototype A. phagocytophilum, was first described 1932 Scotland. A similar disease a related horses USA 1969; this followed description two distinct agents causing diseases dogs 1971 1982. Until discovery anaplasmosis (HGA) 1994, these organisms were thought to be bacteria infecting specific domestic animals free-living reservoirs. It now widely accepted that affecting different animal hosts are variants same Gram-negative obligatory intracellular bacterium, transmitted hard ticks belonging Ixodes persulcatus complex. One its fascinating features it infects actively grows neutrophils employing an array mechanisms subvert their bactericidal activity. also able survive within apparently immune host complex mechanism antigenic variation. Ruminants with TBF humans HGA develop severe febrile reaction, bacteraemia leukopenia due neutropenia, lymphocytopenia thrombocytopenia week exposure tick bite. Because haematological disorders lasting for several days other adverse effects on host's functions, infected more susceptible infections.