Lyme disease
Overview
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 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...

 belonging to the genus
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...

 Borrelia
Borrelia
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...

. 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....

 sensu stricto
is the main cause of Lyme disease in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, whereas 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....

and Borrelia garinii
Borrelia garinii
Borrelia garinii is a spirochete bacteria and part of the Borrelia genus. - External links :****...

cause most Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an cases. The disease is named after the town of Lyme
Lyme, Connecticut
Lyme is a town in New London County, Connecticut, United States. The population was 2,016 at the 2000 census. Lyme and its neighboring town Old Lyme are the namesake for Lyme disease.-Geography:...

, Connecticut
Connecticut
Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...

, USA, where a number of cases were identified in 1975. Although Allen Steere
Allen Steere
Allen C. Steere is a professor of rheumatology at Harvard University and previously at Yale University. Steere is credited with discovering and naming Lyme disease, and he published almost 200 scholarly articles on Lyme disease between 1977 and 2007. At a ceremony in Hartford, Connecticut in 1998,...

 realized that Lyme disease was a tick-borne disease
Tick-borne disease
Tick-borne diseases are diseases or illnesses transmitted by ticks. As the incidence of tick-borne illnesses increases and the geographic areas in which they are found expand, it becomes increasingly important that health professionals be able to distinguish the diverse, and often overlapping,...

 in 1978, the cause of the disease remained a mystery until 1981, when B.
 
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