Borrelia
Encyclopedia
Borrelia is a genus
of bacteria
of the spirochete phylum. It causes borreliosis, a zoonotic, vector-borne disease transmitted primarily by ticks and some by lice, depending on the species. There are 36 known species of Borrelia.
or borreliosis
and are transmitted by ticks. The major Borrelia species causing Lyme disease are Borrelia burgdorferi
, Borrelia afzelii
, Borrelia garinii
and Borrelia valaisiana.
. Borrelia 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 Borrelia hermsii
or Borrelia parkeri
or Borrelia miyamotoi
, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector. Borrelia hermsii
and Borrelia recurrentis
cause very similar diseases, although the disease associated with Borrelia 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.
Laboratory test
that is about 900 kbp in length as well as a plethora of both linear and circular plasmid
s in the 5-220 kbp size range. Genome sequences have been determined for B. burgdorferi, B. garinii, B. afzelii, B. duttonii and B. recurrentis. The chromosomes, which carry the vast majority of the housekeeping genes, appear to be very constant in gene content and organization across the genus. The content of the plasmids, which carry most of the genes that encode the differentially-expressed surface proteins that interact with Borrelia's arthropod
and vertebrate
hosts, are much more variable. B. burgdorferi strain B31, the B. burgdorferi type strain, has been studied in the most detail and harbors twelve linear and nine circular plasmids that comprise about 612 kbp. The plasmids are unusual, as compared to most bacterial plasmids, in that they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. In addition, a number of the plasmids have features suggesting that they are prophage
s. Some correlations between genome content and pathogenicity have been deduced and comparative whole genome analyses promise future progress in this arena.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
of the spirochete phylum. It causes borreliosis, a zoonotic, vector-borne disease transmitted primarily by ticks and some by lice, depending on the species. There are 36 known species of Borrelia.
Lyme disease
Of the 36 known species of Borrelia, 12 of these species are known to cause Lyme diseaseLyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
or borreliosis
Amédée Borrel
Amédée Borrel was a French biologist born in Cazouls-lès-Béziers, Hérault.He studied natural sciences at the University of Montpellier, where he earned his degree in 1890...
and are transmitted by ticks. The major Borrelia species causing Lyme disease are Borrelia burgdorferi
Borrelia burgdorferi
Borrelia burgdorferi is a species of Gram negative bacteria of the spirochete class of the genus Borrelia. B. burgdorferi is predominant in North America, but also exists in Europe, and is the agent of Lyme disease....
, Borrelia afzelii
Borrelia afzelii
Borrelia afzelii is a species of Borrelia that can infect various species of vertebrate and invertebrates.Among thirty Borrelia known species, it is one of 4 which is likely to infect humans causing a variant of Lyme disease....
, Borrelia garinii
Borrelia garinii
Borrelia garinii is a spirochete bacteria and part of the Borrelia genus. - External links :****...
and Borrelia valaisiana.
Relapsing fever
Relapsing fever borreliosis often occurs with severe bacteremiaBacteremia
Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....
. Borrelia 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 Borrelia hermsii
Borrelia hermsii
Borrelia hermsii is a species of Borrelia.It can be associated with relapsing fever.It can infect Ornithodoros hermsi....
or Borrelia parkeri
Borrelia parkeri
Borrelia parkeri is a species of Borrelia.It can be associated with relapsing fever....
or Borrelia miyamotoi
Borrelia miyamotoi
Borrelia miyamotoi is a spirochete bacteria and part of the Borrelia genus. A zoonotic bacteria, B. miyamotoi can be transferred to humans through the deer tick , the same tick species that spreads B. burgdorferi, the causative agent of Lyme Disease...
, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector. Borrelia hermsii
Borrelia hermsii
Borrelia hermsii is a species of Borrelia.It can be associated with relapsing fever.It can infect Ornithodoros hermsi....
and Borrelia recurrentis
Borrelia recurrentis
Borrelia recurrentis is a species of Borrelia.It can be associated with relapsing fever. B. recurrentis is usually transmitted from person to person via the human body louse....
cause very similar diseases, although the disease associated with Borrelia hermsii
Borrelia hermsii
Borrelia hermsii is a species of Borrelia.It can be associated with relapsing fever.It can infect Ornithodoros hermsi....
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.
Laboratory test
- Immunoflourascent or confirm by serology by observing the organism in blood of patient.
Genetics
All members of the Borrelia genus that have been examined harbor a linear chromosomeChromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
that is about 900 kbp in length as well as a plethora of both linear and circular plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...
s in the 5-220 kbp size range. Genome sequences have been determined for B. burgdorferi, B. garinii, B. afzelii, B. duttonii and B. recurrentis. The chromosomes, which carry the vast majority of the housekeeping genes, appear to be very constant in gene content and organization across the genus. The content of the plasmids, which carry most of the genes that encode the differentially-expressed surface proteins that interact with Borrelia's arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
and vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
hosts, are much more variable. B. burgdorferi strain B31, the B. burgdorferi type strain, has been studied in the most detail and harbors twelve linear and nine circular plasmids that comprise about 612 kbp. The plasmids are unusual, as compared to most bacterial plasmids, in that they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. In addition, a number of the plasmids have features suggesting that they are prophage
Prophage
A prophage is a phage genome inserted and integrated into the circular bacterial DNA chromosome. A prophage, also known as a temperate phage, is any virus in the lysogenic cycle; it is integrated into the host chromosome or exists as an extrachromosomal plasmid. Technically, a virus may be called...
s. Some correlations between genome content and pathogenicity have been deduced and comparative whole genome analyses promise future progress in this arena.
External links
- Borrelia genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID
- Borrelia Microbe Wiki Page
- NCBI Borrelia Taxonomy Browser
- Walid MS, Ajjan M, Patel N: Borreliosis And Human Granulocytic Anaplasmosis Coinfection With Positive Rheumatoid Factor And Monospot Test: Case-Report. The Internet Journal of Infectious Diseases. 2007; Volume 6, Number 1. http://www.ispub.com/ostia/index.php?xmlPrinter=true&xmlFilePath=journals/ijid/vol6n1/borreliosis.xml