Neoehrlichiosis is a newly discovered disease transmitted by ticks of the genus Ixodes and tick Dermacentor reticulatus. It is caused by the bacterium Candidatus Neoehrlichia mikurensis, which is closely related to Anaplasma phagocytophilum, which causes ehrlichiosis. Bacteria appear to occur throughout Europe.

Neoehrlichia mikurensis infects predominantly elderly immunocompromised individuals; there is only one case where a completely healthy person has become ill. Symptoms of the disease are fever, muscle and joint pain, headache. There can also appear thrombosis, aneurysm and stroke. Because of these symptoms, it is very difficult for doctors to diagnose neoehrlichiosis correctly. This is only possible from blood or bone marrow by polymerase chain reaction (PCR) with specific primers. Serological methods are ineffective.

Doxycycline or rifampin is used for treatment.