Genus Borrelia refers to a group of bacteria that are known to cause various diseases in humans and animals. The most well-known species of Borrelia is Borrelia burgdorferi, which causes Lyme disease. Other species in the genus Borrelia include Borrelia afzelii, Borrelia garinii, and Borrelia hermsii. These species cause different types of diseases such as relapsing fever and tick-borne infections. Synonyms for genus Borrelia include Spirochaeta and Treponema. The genus Borrelia is important to study for the prevention and treatment of the associated diseases. Research in this area is ongoing, with new information constantly emerging about the bacteria and the diseases they cause.