Other tick-borne microorganisms can cause symptoms that differ from those of Lyme borreliosis, often with a more acute course. Fever is the primary clinical warning sign, which may be accompanied by various other symptoms—cutaneous, neuromeningeal, and lymphatic—that help guide diagnosis. A clinical approach makes it relatively straightforward to distinguish Lyme borreliosis from other tick-borne diseases, with the common factor being the tick as the vector. Biological abnormalities (anaemia, thrombocytopenia, cytolysis, etc.) are often present in tick-borne diseases, unlike in Lyme borreliosis.

However, these other infectious agents remain poorly known and understood. Although diagnostic tools exist, they are often not readily accessible in primary care settings or even in hospitals, which likely leads to underdiagnosis of these infections. This final section of the guidelines details eight tick-borne diseases in order of frequency: rickettsiosis, tularaemia, tick-borne encephalitis, tick-borne relapsing fever, anaplasmosis, babesiosis, neoehrlichiosis, and Crimean–Congo haemorrhagic fever. Co-infections, which are very rare, are also presented with their definitions and characteristics.

The choice of doxycycline as the first-line treatment for Lyme borreliosis seems particularly appropriate, as most of these infectious agents (except Babesia and TBEV) are sensitive to this antibiotic.

As scientific research advances, our understanding continues to grow. Agents such as Neoehrlichia are recent discoveries, and their significance in human pathology remains to be fully elucidated. It is expected that in the coming years, expanding knowledge of other tick-borne diseases will improve diagnosis and patient care.