The intercellular bacteria “Candidatus Neoehrlichia”, as e.g. Borrelia, can be transferred by ticks. Approx. 4.2 % of indigenous ticks are infected with this rarely explored bacterium which, until today, has been exclusively identified as pathogenic bacterium in patients with an impairment of the immune system, such as in case of leukemia, rheumatism or after organ transplantation. Now, an interdisciplinary team of researchers has succeeded in diagnosing the bacterium in an otherwise healthy female patient with fever of an unknown origin – and treating it successfully.