{{Short description|Bacterial infection transmitted by fleas}} {{more citations needed|date=January 2019}} {{Infobox medical condition (new) | name = Murine typhus | synonyms = Endemic typhus | image = Chest Xray 40 yr old male acute respiratory distress syndrome as a complication of murine typhus. 13-1421-F1.jpg | caption = Chest Xray of a 40 yr old male in acute respiratory distress syndrome as a complication of murine typhus | pronounce = | field = Infectious disease | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }} '''Murine typhus''', also known as '''endemic typhus''' or '''flea-borne typhus''', is a form of typhus caused by ''Rickettsia typhi'' transmitted by fleas (''Xenopsylla cheopis''), usually on rats, in contrast to epidemic typhus which is usually transmitted by lice.<ref>{{cite book |last1=Li |first1=Li |last2=Li |first2=Guiying |title=Radiology of Infectious Diseases: Volume 2 |chapter=Epidemic and Endemic Typhus |date=2015 |pages=89–94 |doi=10.1007/978-94-017-9876-1_8 |isbn=978-94-017-9875-4 }}</ref><ref>{{Cite web|last=|date=2020-11-13|title=Flea-borne (murine) typhus|url=https://www.cdc.gov/typhus/murine/index.html|access-date=2021-02-27|website=Centers for Disease Control and Prevention|language=en-us}}</ref><ref>{{Cite web|last=|date=2020-11-13|title=Epidemic typhus|url=https://www.cdc.gov/typhus/epidemic/index.html|access-date=2021-02-27|website=Centers for Disease Control and Prevention|language=en-us}}</ref> 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.{{citation needed|date=December 2020}}
==Names== Murine typhus is also commonly known as endemic or flea-borne typhus, other names include shop, urban, Mexican, and rat typhus.<ref name="durden">{{cite book |last1=Durden |first1=Lance A. |last2=Hinkle |first2=Nancy C. |title=Medical and Veterinary Entomology |chapter=Fleas (Siphonaptera) |date=2019 |pages=145–169 |doi=10.1016/b978-0-12-814043-7.00010-8 |isbn=978-0-12-814043-7 }}</ref> ==Signs and symptoms== Symptoms occur after 6–14 days with common symptoms being pyrexia, dermatitis, prostration, delirium, and in severe cases coma. Untreated patients may be bedridden for 2–3 months and some are unable to work.<ref name="durden"/>
==Transmission== ''Rickettsia typhi'' is the causative agent of murine typhus, the primary host species are ''Rattus rattus'' and ''R. norvegicus'' with transmission occurring via the faeces of fleas (typically ''Xenopsylla''). The bacteria is excreted in the faeces of fleas and when a flea bite is scratched or picked at the bacteria enters the skin and commences infection. Other peridomestic rats and rodents are capable of being infected. Rats can also be infected from ''Hoplopleura pacifica'', ''Polyplax spinulosa'', ''Laelaps echidnina'', ''Ornithonyssus bacoti'', and chiggers.<ref name="durden"/>
''R. typhi'' is not lethal to rats and simply causes rickettsaemia (rickettsiae in blood). Fleas feed on infected rats and become infected with the rickettsiae spreading to the midgut epthilelial cells and replicating there, infected cells move to the gut lumen and are excreted with faeces. The most common flea vector is ''Xenopsylla cheopis'' with other species being ''X. astia'', ''X. bantorum'', ''X. brasiliensis'', ''Ctenocephalides felis'', ''Pulex irritans'', ''Leptopsylla segnis'', and ''Nosopsyllus fasciatus''. ''X. cheopis'' has been shown to transfer ''R. typhi'' via bite in experimental settings and it has been theorised that aerosol transmission from faeces is possible as well. Some arthropods such as mites and chiggers can transfer ''R. typhi'' to rats but do not transfer the bacteria to humans.<ref name="durden"/> ==Epidemiology== Murine typhus is a global disease found on all continents bar Antarctica. Significant volumes of cases occur Indonesia, China, North Africa, Central America, and Thailand. In the United States most cases occur in Texas, with homeless people in Houston having significant seropositivity.<ref name="durden"/> ==Diagnosis== Diagnosis of murine typhus in humans is done via testing for antibodies to ''R. typhi'' or isolation of ''R. typhi'' from a blood or tissue sample. Enzyme-linked immunosorbent assays and polymerase chain reaction (PCR) tests can be used in the diagnosis of fleas and other animals.<ref name="durden"/> ==Prognosis== Different strains of ''R. typhi'' have different virulence, with New World strains having a fatality of around 2%, with Old World strains having fatality rates up to 70%. Despite this over 95% of untreated cases recover, although recovery can take 2–3 months.<ref name="durden"/>
==Treatment== Antibiotics are used to treat murine typhus with doxycycline and tetracycline being common.<ref name="durden"/> == See also == * List of mites associated with cutaneous reactions
== References == {{reflist}}
== External links == {{Medical resources | DiseasesDB = 32211 | ICD10 = {{ICD10|A|75|2|a|75}} | ICD9 = {{ICD9|081.0}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D014437 | Orphanet = 83315 }} {{Gram-negative bacterial diseases}} {{Flea-borne diseases}} {{Bacterial cutaneous infections}}
Category:Bacterium-related cutaneous conditions Category:Typhus