Domain Bacteria Family Spirochaetaceae Higher classification Spirochaetaceae Rank Genus | Order Spirochaetales Scientific name Borrelia Phylum Spirochaetes | |
Lower classifications Borrelia recurrentis, Borrelia miyamotoi, Borrelia anserina, Lyme disease spirochete, Borrelia garinii | ||
Lyme disease borrelia burgdorferi
Borrelia is a genus of bacteria of the spirochete phylum. It causes borreliosis, a zoonotic, vector-borne disease transmitted primarily by ticks and by lice, depending on the species. The genus is named after the French biologist Amédée Borrel (1867–1936). There are 52 known species of Borrelia. 21 are members of the Lyme disease group, 29 belong to the relapsing fever group, and two are members of a third group.
Contents
Borrelia bacteria
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 111 by 'The All-Species Living Tree' Project
Notes:
♦ Type strain lost or not available
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)
♥ Strains not lodged at National Center for Biotechnology Information (NCBI) or listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN)
Lyme disease
Of the 52 known species of Borrelia, 12 are known to cause Lyme disease or borreliosis and are transmitted by ticks. The major Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii.
Direct tests include culture of Borrelia from skin, blood, or cerebrospinal fluid (CSF) and detection of genetic material by polymerase chain reaction in skin, blood, or synovial fluid. Two-tiered serological testing is performed for differential diagnosis of Borrelia infection. The first-tier tests detect specific antibodies (IgM and IgG together or separately) and include enzyme immunoassays (e.g. ELISAs) and immunofluorescent assays. Positive results for first-tier tests are confirmed using second-tier testing. The second-tier consists of standardized immunoblotting, either by using Western blots or blots striped with diagnostically important purified antigens. Positive results for second-tier tests are confirmatory for the presence of Borrelia infection.
Relapsing fever
Relapsing fever borreliosis often occurs with severe bacteremia. B. recurrentis is transmitted by the human body louse; no other animal reservoir of B. recurrentis is known. Lice that feed on infected humans acquire the Borrelia organisms that then multiply in the gut of the louse. When an infected louse feeds on an uninfected human, the organism gains access when the victim crushes the louse or scratches the area where the louse is feeding. B. recurrentis infects the person via mucous membranes and then invades the bloodstream.
Other tick-borne relapsing infections are acquired from other species, such as B. hermsii, B. parkeri, or B. miyamotoi, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector. B. hermsii and B. recurrentis cause very similar diseases, although the disease associated with B. hermsii has more relapses and is responsible for more fatalities, while the disease caused by B. recurrentis has longer febrile and afebrile intervals and a longer incubation period.