Rickettsia is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci, bacilli, or threads. The genus was named after Howard Taylor Ricketts in honor of his pioneering work on tick-borne spotted fever.
Rocky Mountain spotted fever (RMSF) is a bacterial disease spread by ticks. It typically begins with a fever and headache, which is followed a few days later with the development of a rash. The rash is generally made up of small spots of bleeding and starts on the wrists and ankles. Other symptoms may include muscle pains and vomiting. Long-term complications following recovery may include hearing loss or loss of part of an arm or leg.
Boutonneuse fever is a fever as a result of a rickettsial infection caused by the bacterium Rickettsia conorii and transmitted by the dog tick Rhipicephalus sanguineus. Boutonneuse fever can be seen in many places around the world, although it is endemic in countries surrounding the Mediterranean Sea. This disease was first described in Tunisia in 1910 by Conor and Bruch and was named boutonneuse due to its papular skin-rash characteristics.
Rickettsia rickettsii is a Gram-negative, intracellular, coccobacillus bacterium that was first discovered in 1902. R. rickettsii is the causative agent of Rocky Mountain Spotted Fever and is transferred to its host via a tick bite. It is one of the most pathogenic Rickettsia species and affects a large majority of the Western Hemisphere, most commonly the Americas.
Robert Joseph Huebner, was an American physician and virologist whose research into viruses, their causes and treatment that led to his breakthrough insights into the connections between viruses and cancer, leading to new treatments, as well as his hypothesized oncogene, which was discovered to be a trigger for normal cells turning cancerous.
Murine typhus, also known as endemic typhus or flea-borne typhus, is a form of typhus transmitted by fleas, usually on rats, in contrast to epidemic typhus which is usually transmitted by lice. Murine typhus is an under-recognized entity, as it is often confused with viral illnesses. Most people who are infected do not realize that they have been bitten by fleas. Historically the term "hunger-typhus" was used in accounts by British POWs in Germany at the end of World War I when they described conditions in Germany.
Orientia tsutsugamushi is a mite-borne bacterium belonging to the family Rickettsiaceae and is responsible for a disease called scrub typhus in humans. It is a natural and an obligate intracellular parasite of mites belonging to the family Trombiculidae. With a genome of only 2.0–2.7 Mb, it has the most repeated DNA sequences among bacterial genomes sequenced so far. The disease, scrub typhus, occurs when infected mite larvae accidentally bite humans. Primarily indicated by undifferentiated febrile illnesses, the infection can be complicated and often fatal.
Rickettsia akari is a species of Rickettsia which causes rickettsialpox.
Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms include fever, headache, and a rash. Typically these begin one to two weeks after exposure.
Rickettsia typhi is a small, aerobic, obligate intracellular, rod shaped gram negative bacterium. It belongs to the typhus group of the Rickettsia genus, along with R. prowazekii. R. typhi has an uncertain history, as it may have long gone shadowed by epidemic typhus. This bacterium is recognized as a biocontainment level 2/3 organism. R. typhi is a flea-borne disease that is best known to be the causative agent for the disease murine typhus, which is an endemic typhus in humans that is distributed worldwide. As with all rickettsial organisms, R. typhi is a zoonotic agent that causes the disease murine typhus, displaying non-specific mild symptoms of fevers, headaches, pains and rashes. There are two cycles of R. typhi transmission from animal reservoirs containing R. typhi to humans: a classic rat-flea-rat cycle that is most well studied and common, and a secondary periodomestic cycle that could involve cats, dogs, opossums, sheep, and their fleas.
Charles Pomerantz was a pest control expert and self-trained entomologist who played a pivotal role in identifying the etiology of a 1946 outbreak in New York City of what was later named rickettsialpox. In subsequent years, he spoke before audiences at colleges and other public forums about the menace from pests.
African tick bite fever (ATBF) is a bacterial infection spread by the bite of a tick. Symptoms may include fever, headache, muscle pain, and a rash. At the site of the bite there is typically a red skin sore with a dark center. The onset of symptoms usually occurs 4–10 days after the bite. Complications are rare but may include joint inflammation. Some people do not develop symptoms.
Queensland tick typhus is a zoonotic disease caused by the bacterium Rickettsia australis. It is transmitted by the ticks Ixodes holocyclus and Ixodes tasmani.
Flea-borne spotted fever or California pseudotyphus is a condition characterized by a rash of maculopapules or furuncles.
Rickettsia parkeri is a gram-negative intracellular bacterium. The organism is found in the Western Hemisphere and is transmitted via the bite of hard ticks of the genus Amblyomma. R. parkeri causes mild spotted fever disease in humans, whose most common signs and symptoms are fever, an eschar at the site of tick attachment, rash, headache, and muscle aches. Doxycycline is the most common drug used to reduce the symptoms associated with disease.
Ornithonyssus bacoti is a hematophagous parasite. It feeds on blood and serum from many hosts. O. bacoti can be found and cause disease on rats and wild rodents most commonly, but also small mammals and humans when other hosts are scarce. Outbreaks tend to occur in older, less maintained buildings. The mite, however, can travel several hundred feet on its own if necessary to find a host and can survive for extended periods of time without a host. This, along with the nonspecific dermatitis it causes, can prevent accurate and fast diagnosis of rat mite dermatitis. The scarcity of reports, due in part to misdiagnosis and also the mildness of its symptoms, makes the disease seem less common than it is. The tropical rat mite can be found in both temperate and tropical regions or rather all continents except the Arctic and Antarctic.
Liponyssoides sanguineus is a species of mite that infests the house mouse.
Rickettsia felis is a species of bacterium, the pathogen that causes cat-flea typhus in humans, also known as flea-borne spotted fever. Rickettsia felis also is regarded as the causative organism of many cases of illnesses generally classed as fevers of unknown origin in humans in Africa.
Rodent mite dermatitis is an often unrecognized ectoparasitosis occurring after human contact with haematophagous mesostigmatid mites that infest rodents, such as house mice, rats and hamsters. The condition is associated with the tropical rat mite, spiny rat mite and house mouse mite which opportunistically feed on humans. Rodent mites are capable of surviving for long periods without feeding and travelling long distances when seeking hosts. Cases have been reported in homes, libraries, hospitals and care homes. A similar condition, known as gamasoidosis, is caused by avian mites.
