In veterinary medicine, clinical manifestations are the most reliable tool for Lyme diagnosis. In human, the current diagnosis is based mainly on a patient’s clinical examination coupled to a two-step serology (ELISA and Western Blot). Direct diagnosis relies on bacterial culture, often long and tedious, and PCR. Generally, early diagnosis will pose any problem because of the pathognomonic sign of the disease: the EM. However, this event is not present in all patients: only 80% of the population has this clinical manifestation (Stanek et al., 2012). Late diagnosis is more complex given the multitude of organs targeted by the bacteria.