Lyme borreliosis (LB), also known as Lyme disease is an infectious disease caused by bacteria Borrelia burgdorferi sensu lato (s.l.) complex.
Borrelia are microorganisms belonging to a large family of spiral-shape bacteria designated by spirochetes. These are transmitted to humans and animals through the bite of infected ticks, especially Ixodes genus.
In the complex B. burgdorferi s.l., there are several species although not all cause disease. In Portugal, are known at least, five pathogenic species, including B. burgdorferi sensu stricto (s.s.), B. afzelii, B. valaisiana, B. garinii and B. lusitanaie, the latter for the first time isolated in our country in 2003, from the skin of a patient.
The most common symptoms usually include a redness of the skin at the site of the tick bite, designated by erythema migrans weakness, fatigue, fever, chills and muscle and joint aches, and can also later be affected other organs and systems like the heart and the central nervous system (CNS) with the appearance of facial paralysis and other manifestations.
The diagnosis is primarily clinical, but laboratory tests (serological and /or molecular) are of great importance in supporting the diagnosis and therapy.