Lyme disease

Lyme disease or Lyme borreliosis is an infectious tick-borne disease, caused by the Borrelia spirochete, a gram-negative microorganism.

Microbiology

The disease is caused by the parasite Borrelia, which has well over three hundred known genomic strains but is usually cultured as Borrelia burgdorferi, Borrelia afzelii and Borellia garinii. Different Borrelia strains are predominant in Europe and North America.

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The disease has been found to be transmitted to humans by the bite of infected Ixodes ticks. Not all ticks carry or can transmit this particular disease. It should also be noted that in a few cases the disease may also be transmitted by other blood-sucking parasitic insects such as mosquitoes, fleas or blackflies. However other Borrelia strains (i.e. B. garinii) are probably transmitted this way.

Related Topics:
Mosquito - Flea - Blackflies

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Other tick-borne infections may be transmitted simultaneously with Lyme, including Bartonella, Babesiosis, Ehrlichiosis, and Rickettsia.

Related Topics:
Bartonella - Babesiosis - Ehrlichiosis - Rickettsia

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Borrelia burgdorferi resembles other spirochetes in that it is a highly specialized, motile, two-membrane, spiral-shaped bacterium which lives primarily as an extracellular pathogen. One of the most striking features of Borrelia burgdorferi as compared with other eubacteria is its unusual genome, which includes a linear chromosome approximately one megabase in size and numerous linear and circular plasmids.

Related Topics:
Bacterium - Eubacteria - Genome - Chromosome - Plasmid

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Long-term culture of Borrelia burgdorferi results in a loss of some plasmids and changes in expressed protein profiles. Associated with the loss of plasmids is a loss in the ability of the organism to infect laboratory animals, suggesting that the plasmids encode key genes involved in virulence.

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Borrelia burgdorferi may persist in humans and animals for months or years following initial infection, despite a robust humoral immune response. Borrelia burgdorferi is susceptible to antibiotics in vitro. However, there are contradictory reports as to the efficacy of antibiotics in vivo in regard to complete eradication of the bacterium from the host. Borrellia burgdorpherri has been isolated in skin specimens of white-footed mice in museum specimens as far back as the 1870s in Massachusetts.

Related Topics:
Antibiotics - In vitro - In vivo - 1870s - Massachusetts

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