Lyme disease, also known as Lyme borreliosis, is a tick-borne disease caused by species of Borrelia bacteria, transmitted by blood-feeding ticks in the genus Ixodes. The most common sign of infection is an expanding red rash, known as erythema migrans (EM), which appears at the site of the tick bite about a week afterwards. The rash is typically neither itchy nor painful. Approximately 70–80% of infected people develop a rash. Early diagnosis can be difficult. Other early symptoms may include fever, headaches and tiredness. If untreated, symptoms may include loss of the ability to move one or both sides of the face, joint pains, severe headaches with neck stiffness or heart palpitations. Months to years later, repeated episodes of joint pain and swelling may occur. Occasionally, shooting pains or tingling in the arms and legs may develop.
Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. The economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide. Most of these pathogens require passage through vertebrate hosts as part of their life cycle. Tick-borne infections in humans, farm animals, and companion animals are primarily associated with wildlife animal reservoirs. Many tick-borne infections in humans involve a complex cycle between wildlife animal reservoirs and tick vectors. The survival and transmission of these tick-borne viruses are closely linked to their interactions with tick vectors and host cells. These viruses are classified into different families, including Asfarviridae, Reoviridae, Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, and Flaviviridae.
Borrelia burgdorferi is a bacterial species of the spirochete class in the genus Borrelia, and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it makes up the species complex of Borrelia burgdorferi sensu lato. The complex currently comprises 20 accepted and 3 proposed genospecies. B. burgdorferi sensu stricto exists in North America and Eurasia and until 2016 was the only known cause of Lyme disease in North America. B. burgdorferi are often mistakenly described as Gram negative because of their two external membranes, but they lack lipopolysaccharide and possess many surface lipoproteins, unlike true Gram-negative bacteria.
Dermacentor variabilis, also known as the American dog tick or wood tick, is a species of tick that is known to carry bacteria responsible for several diseases in humans, including Rocky Mountain spotted fever and tularemia. It is one of the best-known hard ticks. Diseases are spread when it sucks blood from the host. It may take several days for the host to experience symptoms.
Relapsing fever is a vector-borne disease caused by infection with certain bacteria in the genus Borrelia, which is transmitted through the bites of lice, soft-bodied ticks, or hard-bodied ticks.
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, 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, 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.
Lyme disease, or borreliosis, is caused by spirochetal bacteria from the genus Borrelia, which has 52 known species. Three species are the main causative agents of the disease in humans, while a number of others have been implicated as possibly pathogenic. Borrelia species in the species complex known to cause Lyme disease are collectively called Borrelia burgdorferisensu lato (s.l.), not to be confused with the single species Borrelia burgdorferi sensu stricto, a member of the complex, which is responsible for nearly all cases of Lyme disease in North America.
Ixodes scapularis is commonly known as the deer tick or black-legged tick, and in some parts of the US as the bear tick. It was also named Ixodes dammini until it was shown to be the same species in 1993. It is a hard-bodied tick found in the eastern and northern Midwest of the United States as well as in southeastern Canada. It is a vector for several diseases of animals, including humans and is known as the deer tick owing to its habit of parasitizing the white-tailed deer. It is also known to parasitize mice, lizards, migratory birds, etc. especially while the tick is in the larval or nymphal stage.
Allen Caruthers Steere is an American rheumatologist. He is a professor of rheumatology at Harvard University and previously at Tufts University and Yale University. Steere and his mentor, Stephen Malawista of Yale University, are credited with discovering and naming Lyme disease, and he has published almost 300 scholarly articles on Lyme disease during his more than 40 years of studies of this infection. At a ceremony in Hartford, Connecticut in 1998, Governor John G. Rowland declared September 24 to be "Allen C. Steere Day".
Virulence-related outer membrane proteins, or outer surface proteins (Osp) in some contexts, are expressed in the outer membrane of gram-negative bacteria and are essential to bacterial survival within macrophages and for eukaryotic cell invasion.
Southern tick-associated rash illness (STARI) is an emerging infectious disease related to Lyme disease that occurs in southeastern and south-central United States. It is spread by tick bites and it was hypothesized that the illness was caused by the bacteria Borrelia lonestari. However, there is insufficient evidence to declare this Borrelia strain as a causative agent.
Human granulocytic anaplasmosis (HGA) is a tick-borne, infectious disease caused by Anaplasma phagocytophilum, an obligate intracellular bacterium that is typically transmitted to humans by ticks of the Ixodes ricinus species complex, including Ixodes scapularis and Ixodes pacificus in North America. These ticks also transmit Lyme disease and other tick-borne diseases.
Ixodes pacificus, the western black-legged tick, is a species of tick found on the western coast of North America. I. pacificus is a member of the family Ixodidae. It is the principal vector of Lyme disease in that region. I. pacificus larvae and nymphs typically feeds on lizards and small mammals, while adults typically feed on deer. It is an ectoparasite that attaches itself to the outside of its host and feeds on the host's blood. It can have a heteroxenous lifestyle or monoxenous life cycle depending on how many hosts it feeds on in each cycle. I. pacificus has a four-stage life cycle that takes around 3 years to complete. These stages include egg, larva, nymph, and adult. They prefer dense woodland habitats or areas of brush and tall grass.
Ixodes persulcatus, the taiga tick, is a species of hard-bodied tick distributed from Europe through central and northern Asia to the People's Republic of China and Japan. The sexual dimorphism of the species is marked, the male being much smaller than the female. Hosts include wild and domestic ungulates, man, dog, rabbit, and other small mammals, including the dormouse, Amur hedgehog, and occasionally birds.
Transstadial transmission is the persistence of a symbiont or pathogen in an organism from one life stage ("stadium") to the next, such as larva to nymph to adult. This type of transmission is typically observed in insects. For example, the bacterium Borrelia burgdorferi, the causative agent for Lyme disease, infects the tick vector as a larva, with the infection maintained as the tick molts to a nymph and later develops as an adult. Transstadial transmission is also seen with other microbes such as other bacteria, fungi, and viruses in numerous insects. In addition to ticks, mites are another common vector. Transstadial transmission is especially relevant to public health, as several threats to public health are maintained in insect populations by transstadial transmission. Some debate exists regarding the classification of transstadial transmission as vertical transmission versus horizontal transmission. Reasons for this stem from further debate regarding transovarial transmission, described as the passage of a symbiont or pathogen from an infected female to its progeny, especially in eggs.
Borrelia spielmanii is a spirochete bacterium; it routinely infects Ixodes ricinus, and subsequently humans, causing Lyme disease.
Borrelia andersonii is a spirochete bacterium. It can be pathogenic, being involved in cases of Lyme borreliosis.
Borrelia turicatae is a bacterial species of the spirochaete class of the genus Borrelia. It is one of the relapsing fever spirochaetes, which are globally distributed yet understudied agents of tick-borne relapsing fever. The tick vector Ornithodoros turicata transmits B. turicatae, which causes relapsing fever, an arthropod-borne infection of humans and other mammals caused by different Borrelia species. B. turicatae is long and spiral-shaped, as is typical for all spirochaetes. It is a Gram-negative bacterium and visible with light microscopy. Few epidemiological studies have been performed and few molecular data exist for B. turicatae and its arthropod vector O. turicata.
Baggio–Yoshinari syndrome, formerly known as the Brazilian Lyme-like disease and Brazilian human borreliosis, is a disease transmitted by the bites of Amblyomma and Rhipicephalus genera ticks, but the organism that causes the infection is a distinct variant of the bacteria that causes Lyme with different markers that cannot be reliably detected by the standard North American tests. Clinical features resemble those of Lyme disease (LD) but have distinctive differences.
Borrelia mayonii is a Gram-negative, host-associated spirochete that is capable of causing Lyme disease. This organism can infect various vertebrate hosts such as humans via the bite of a black legged tick.
