''Rickettsia prowazekii'' is a species of

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

alphaproteobacteria Alphaproteobacteria is a class of bacteria in the phylum Pseudomonadota (formerly Proteobacteria). The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria. The Alphaproteobacteria are highly diverse and ...

obligate {{wiktionary, obligate As an adjective, obligate means "by necessity" (antonym ''facultative'') and is used mainly in biology in phrases such as: * Obligate aerobe, an organism that cannot survive without oxygen * Obligate anaerobe, an organism tha ...

intracellular parasitic,

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cel ...

bacillus ''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum '' Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacill ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

that is the etiologic agent of epidemic typhus, transmitted in the feces of lice. In North America, the main reservoir for ''R. prowazekii'' is the

flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 50 species of squirrels in the family Sciuridae. Despite their name, they are not in fact capable of full flight in the same way as birds or bats, but they a ...

. ''R. prowazekii'' is often surrounded by a protein microcapsular layer and

slime layer A slime layer in bacteria is an easily removable (e.g. by centrifugation), unorganized layer of extracellular material that surrounds bacteria cells. Specifically, this consists mostly of exopolysaccharides, glycoproteins, and glycolipids. Therefo ...

; the natural life cycle of the bacterium generally involves a

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...

and an

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

host, usually an

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...

, typically the

human body louse The body louse (''Pediculus humanus humanus'', also known as ''Pediculus humanus corporis'') is a hematophagic ectoparasite louse that infests humans. It is one of three lice which infest humans, the other two being the head louse, and the cr ...

. A form of ''R. prowazekii'' that exists in the feces of arthropods remains stably infective for months. ''R. prowazekii'' also appears to be the closest free-living relative of

mitochondria A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...

, based on genome sequencing.

History

Discovery

Henrique da Rocha Lima Henrique da Rocha Lima (24 November 1879 – 12 April 1956) was a Brazilian physician, pathologist and infectologist born in Rio de Janeiro. With his friend, Stanislaus von Prowazek, he described what would later be known as ''Rickettsia prowaz ...

, a Brazilian doctor, discovered this bacterium in 1916. He named it after his colleague Stanislaus von Prowazek, who had died from typhus in 1915. Both Prowazek and Rocha Lima had been infected with typhus while studying its causative agent in a prison hospital in

Hamburg Hamburg (, ; nds, label=Hamburg German, Low Saxon, Hamborg ), officially the Free and Hanseatic City of Hamburg (german: Freie und Hansestadt Hamburg; nds, label=Low Saxon, Friee un Hansestadt Hamborg),. is the List of cities in Germany by popul ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

. This bacterium lacks flagella and is aerobic. It is stained gram-negative.

Genome

The genome of ''R. prowazekii'' is reduced, being about 1Mb in size and encoding 834 proteins. Some strains encode 866 proteins. They do not encode all the proteins required to live on their own. Missing activities have to be provided by its host, a eukaryotic cell. For this reason, ''R. prowazekii'' has sometimes been regarded as a model for the intracellular bacterial ancestor of

Treatment

Vaccines against ''R. prowazekii'' were developed in the 1940s, and were highly effective in reducing typhus deaths among U.S. soldiers during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

Immunity Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity de ...

following recovery from infection with, or by immunization against, ''R. prowazekii'' is lifelong in most cases. However, ''R. prowazekii'' can establish a

latent Latency or latent may refer to: Science and technology * Latent heat, energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process * Latent variable, a variable that is not directly observed but inferred ...

infection, which can reactivate after years or decades (referred to as Brill-Zinsser disease). Treatment with

tetracycline Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis. Common side effects in ...

antibiotics is usually successful.

References

External links

''Rickettsia prowazekii'' Taxon Overview
at

Virginia Bioinformatics Institute The Biocomplexity Institute of Virginia Tech (formerly the Virginia Bioinformatics Institute) is a research organization specializing in bioinformatics, computational biology, and systems biology. The institute has more than 250 personnel, incl ...

NIAID Biodefense Research Agenda for Category B and C Priority Pathogens
from the US

National Institute of Allergy and Infectious Diseases The National Institute of Allergy and Infectious Diseases (NIAID, ) is one of the 27 institutes and centers that make up the National Institutes of Health (NIH), an agency of the United States Department of Health and Human Services (HHS). NIAID's ...

{{Taxonbar, from=Q952862 Rickettsiaceae Zoonoses Epidemic typhus Bacteria described in 1916