''Borrelia'' is a
genus of
bacteria of the
spirochete phylum.
Several species cause
Lyme disease, also called Lyme borreliosis, a
zoonotic,
vector-borne disease transmitted by
ticks. Other species of ''Borrelia'' cause
relapsing fever, and are transmitted by ticks or
lice
Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...
, depending on the species of bacteria. A few ''Borrelia'' species as ''Candidatus'' Borrelia mahuryensis harbor intermediate genetic features between Lyme disease and relapsing fever ''Borrelia''.
The genus is named after French biologist
Amédée Borrel (1867–1936), who first documented the distinction between a species of ''Borrelia'', ''B. anserina'', and the other known type of spirochete at the time, ''
Treponema pallidum''.
This bacterium must be viewed using
dark-field microscopy,
which make the cells appear white against a dark background. ''Borrelia'' species are grown in Barbour-Stoenner-Kelly medium.
Of 52 known species of ''Borrelia'', 20 are members of the Lyme disease group (with an additional 3 proposed), 29 belong to the relapsing fever group, and two are members of a genetically distinct third group typically found in reptiles.
A proposal has been made to split the Lyme disease group based on genetic diversity and move them to their own genus, ''Borelliella'', but this change is not widely accepted.
This bacterium uses hard and soft ticks and lice as vectors.
Testing for the presence of the bacteria in a human includes two-tiered serological testing, including immunoassays and immunoblotting.
Biology
''Borrelia'' species are members of the family Spirochaetaceae, so present the characteristic
spirochete (spiral) shape. Most species are obligate anaerobes, although some are aerotolerant. ''Borrelia'' species have an outer membrane that contains a substance similar to lipopolysaccharides, an inner membrane, and a layer of peptidoglycan in a periplasmic space, which classifies them as Gram-negative.
However, this result is not easily visualized using
Gram staining.
They are typically 20–30 μm long and 0.2–0.3 μm wide.
Spirochetes move using axial filaments called
endoflagella in their periplasmic space.
The filaments rotate in this space, between the outer membrane and the peptidoglycan layer, propelling the bacterium forward in a corkscrew-like motion.
The outer membrane of ''Borrelia'' species contains outer surface proteins (Osp) that play a role in their virulence.
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).
Notes:
♦ Type strain lost or not available
Unassigned species:
* "''Ca.''
Borrelia africana
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
"
Ehounoud et al. 2016
* "''Ca.''
Borrelia algerica"
Fotso et al. 2015
* "''Ca.''
Borrelia aligera
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Norte et al. 2020
* ''
Borrelia baltazardii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
''
corrig. Karimi et al. 1979 ex Karimi et al. 1983
* ''
Borrelia brasiliensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
'' ♦
Davis 1952
* ''
Borrelia caucasica
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Kandelaki 1945) Davis 1957
* ''
Borrelia dugesii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Mazzotti 1949) Davis 1957
* "''Ca.''
Borrelia fainii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Qiu et al. 2019
* ''
Borrelia graingeri
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Heisch 1953) Davis 1957
* ''
Borrelia harveyi
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Garnham 1947) Davis 1948
* "''Ca.''
Borrelia ibitipocensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
corrig. Muñoz-Leal et al. 2020
* "''Ca.''
Borrelia ivorensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Ehounoud et al. 2016
* "''Ca.''
Borrelia javanense
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Jiang et al. 2021
* "''Ca.''
Borrelia johnsonii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Schwan et al. 2009
* "''Ca.''
Borrelia kalaharica
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Fingerle et al. 2016
* ''
Borrelia latyschewii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Sofiev 1941) Davis 1948
* "''
Borrelia lonestari''"
Barbour et al. 1996
* "''Ca.''
Borrelia mahuryensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Binetruy et al. 2020
* ''
Borrelia mazzottii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
'' ♦
Davis 1956
* "''
Borrelia merionesi
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
''"
Hougen 1974
* "''
Borrelia microti
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
''"
(Rafyi 1946) Davis 1948
* "''Ca.''
Borrelia mvumii
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
"
Mitani et al. 2004
* "''
Borrelia myelophthora
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
''"
(Steiner 1931) Ahrens & Muschner 1958
* "''Ca.''
Borrelia paulista
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
"
Weck et al. 2022
* "''
Borrelia puertoricensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, and a ...
''"
Bermudez et al. 2021
* ''
Borrelia theileri
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Laveran 1903) Bergey et al. 1925
* ''
Borrelia tillae
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, Vector (epidemiology), vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause rela ...
'' ♦
Zumpt & Organ 1961
* ''
Borrelia venezuelensis
''Borrelia'' is a genus of bacteria of the spirochete phylum. Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of ''Borrelia'' cause relapsing fever, an ...
'' ♦
(Brumpt 1921) Brumpt 1922
* ''
Borreliella americana''
(Rudenko et al. 2010) Adeolu & Gupta 2018
* "''
Borreliella andersonii''"
(Marconi, Liveris & Schwartz 1995) Adeolu & Gupta 2014
* ''
Borreliella carolinensis''
(Rudenko et al. 2011) Adeolu & Gupta 2015
* ''
Borreliella kurtenbachii''
(Margos et al. 2013) Adeolu & Gupta 2015
* "''
Borreliella lusitaniae''"
(Le Fleche et al. 1997) Adeolu & Gupta 2014
* "''
Borreliella tanukii''"
(Fukunaga et al. 1997) Adeolu & Gupta 2014
* ''
Borreliella sinica''
(Masuzawa et al. 2001) Adeolu & Gupta 2015
* "''Ca.''
Borreliella texasensis"
(Lin et al. 2005) Adeolu & Gupta 2014
Vectors
Ticks
Hard ticks of the family
Ixodidae are common vectors of ''Borellia'' bacteria
and are the only type of ticks shown to transmit Lyme disease bacteria to humans.
Some tick species of the ''Ambylomma'' genus are vectors of ''Candidatus'' Borrelia mahuryensis in South America.
Other species are carried by soft ticks. The soft tick ''
Ornithodoros'' carries the species of ''Borellia'' that cause relapsing fever.
Another species, ''B. anserina'', is carried by the soft tick ''
Argas
''Argas'' is a genus of tick.
Species
* '' Argas abdussalami'' Hoogstraal & McCarthy, 1965
* '' Argas acinus'' Whittick, 1938
* '' Argas africolumbae'' Hoogstraal, Kaiser, Walker, Ledger, Converse & Rice, 1975
* '' Argas arboreus'' Kaiser, Hoo ...
''.
Inside the ticks, the bacteria grow in the midgut and then travel to the salivary glands to be transmitted to a new host.
Ticks can spread the bacteria to each other when co-feeding.
If an animal has been infected by a tick and then is bitten by a second tick, the second tick can become infected.
The bacteria are most commonly transmitted to humans through ticks in the nymph stage of development, because they are smaller and less likely to be noticed and removed.
The ticks must have around 36 to 48 hours of contact with a host to successfully transmit the bacteria.
Lice
Lice
Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...
that feed on infected humans acquire the ''Borrelia'' organisms that then multiply in the hemolymph and gut of the lice.
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.
The U. S.
Centers for Disease Control and Prevention reported that no credible evidence shows that lice can carry ''Borrelia''.
Lyme disease
Of the 52 known species of ''Borrelia'', 20 belong to the Lyme disease group and are transmitted by ticks.
Eight are known to cause
Lyme disease or
Borreliosis. The major ''Borrelia'' species causing Lyme disease are ''
Borrelia burgdorferi'', ''
Borrelia afzelii'', and ''
Borrelia garinii''.
All species that cause Lyme disease are referred to collectively as ''B. burgdorferi'' ''sensu lato'',
while ''B. burgdorferi'' itself is specified as ''B. burgdorferi'' ''sensu stricto''.
''B. burgdorferi'' was previously believed to be the only species to cause Lyme disease in the US, but ''B. bissettiae'' and a new species called ''B. mayonii'' cause Lyme disease in the US, as well.
The remaining five human pathogenic species occur only in Europe and Asia.
Relapsing fever
Relapsing fever (RF) borreliosis often occurs with severe
bacteremia
Bloodstream infections (BSIs), which include bacteremias when the infections are bacterial and fungemias when the infections are fungal, are infections present in the blood. Blood is normally a sterile environment, so the detection of microb ...
.
Twenty-five species of ''Borrelia '' are known to cause relapsing fever.
While most species use the soft tick family
Argasidae as their vector, some outliers live in hard ticks or lice.
Relapsing fever can be spread epidemically through lice or endemically through ticks.
''B. recurrentis'', a common species underlying relapsing fever, is transmitted by the human body
louse
Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...
; no other animal reservoir of ''B. recurrentis'' is known.
''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
''Borrelia recurrentis'' is a species of ''Borrelia'', a spirochaete bacterium associated with relapsing fever. ''B. recurrentis'' is usually transmitted from person to person by the human body louse
The body louse (''Pediculus humanus humanu ...
'' 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.
Diagnosis
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-linked
immunoassays (e.g.
ELISAs) and
immunofluorescent
Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily on microbiological samples. This technique uses the specificity of antibodies to their antigen to target fluorescent dyes to specifi ...
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.
Spirochetes can also be seen using
Wright-stained blood smears.
References
Further reading
*
*
External links
Borreliagenomes and related information a
PATRIC a Bioinformatics Resource Center funded b
NIAIDBorrelia Microbe Wiki PageNCBI Borrelia Taxonomy Browser
{{Taxonbar, from=Q115528
Lyme disease
Spirochaetes
Bacteria genera