**9. Differential diagnosis**

In addition to a variety of viral infections, differential diagnosis of the initial (viremic) phase of TBE includes also several diseases caused by bacteria. There is a striking similarity in clinical and laboratory presentation of the initial phase of TBE and human granulocytic anaplasmosis. For both diseases fever, headache, leukopenia, and thrombocytopenia are typical. However, the presence of clinical symptoms such as chills, myalgia and arthralgia, and laboratory findings of elevated concentration of C‐reactive protein and lactate dehydrogenase values direct toward the diagnosis of human granulocytic anaplasmosis and against the initial phase of TBE [119].

TBE needs to be differentiated from encephalitis or aseptic meningitis due to many other viruses. Differential diagnosis comprises also other tick‐borne diseases such as Lyme borreliosis, babesiosis, human granulocytic anaplasmosis, tick‐transmitted rickettsioses, and tularemia. Since these diseases are treatable with antibiotics, caution must be taken to distinguish them from TBE [32].

Concomitant TBEV and *Borrelia burgdorferi* sensu lato infections, as well as concomitant TBEV and *Anaplasma phagocytophilum* infections have been described [77, 113, 120–122].
