Human Anaplasmosis Presenting as Atypical Pneumonitis in France

Human anaplasmosis is a febrile illness caused by Anaplasma phagocytophilum, an intracellular bacterium transmitted by Ixodes ticks in the United States and Europe. Although cough is reported in 30% of the American cases, interstitial pneumonitis has been noted only once. Of the 9 confirmed cases reported in Europe, 3 presented with atypical pneumonitis. A. phagocytophilum should be added to the list of agents responsible for interstitial pneumonitis, especially in areas where human anaplasmosis is endemic.