Rickettsia felis
{{Short description|Species of bacterium}}
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| genus = Rickettsia
| species = felis
| parent = Spotted fever group
| authority = Bouyer et al., 2001{{cite journal |vauthors=Bouyer DH, Stenos J, Crocquet-Valdes P, etal |title=Rickettsia felis: molecular characterization of a new member of the spotted fever group |journal=Int. J. Syst. Evol. Microbiol. |volume=51 |issue=Pt 2 |pages=339–47 |date=March 2001 |pmid=11321078 |url=http://ijs.sgmjournals.org/content/51/2/339.short |doi=10.1099/00207713-51-2-339 |doi-access=free }} emend. La Scola et al., 2002{{cite journal |vauthors=La Scola B, Meconi S, Fenollar F, Rolain JM, Roux V, Raoult D |title=Emended description of Rickettsia felis (Bouyer et al. 2001), a temperature-dependent cultured bacterium |journal=Int. J. Syst. Evol. Microbiol. |volume=52 |issue=Pt 6 |pages=2035–41 |date=November 2002 |pmid=12508865 |url=http://ijs.sgmjournals.org/content/52/6/2035.short |doi=10.1099/00207713-52-6-2035 |doi-access=free }}
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Rickettsia felis is a species of bacterium, the pathogen that causes cat-flea typhus in humans, also known as flea-borne spotted fever.{{cite book |first1=Didier |last1=Raoult |first2=Philippe |last2=Parola |title=Rickettsial diseases |url=https://books.google.com/books?id=BSGuWFv_qf0C&pg=PA87 |access-date=23 May 2010 |year=2007 |publisher=CRC Press |isbn=978-0-8493-7611-5 |pages=87–}} 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.
Transmission and concerns
Fleas are the main vectors of Rickettsia felis and it is present in cat fleas worldwide. Human infection usually results from flea feces coming into contact with scratched or broken skin. Human infection is known as cat flea rickettsiosis, flea-borne spotted fever, and cat flea typhus.{{cite journal |vauthors=Azad AF, Beard CB |title=Rickettsial pathogens and their arthropod vectors |journal=Emerging Infect. Dis. |volume=4 |issue=2 |pages=179–86 |year=1998 |pmid=9621188 |pmc=2640117 |doi=10.3201/eid0402.980205 }}{{cite book | last=Durden | first=Lance A. | last2=Hinkle | first2=Nancy C. | title=Medical and Veterinary Entomology | chapter=Fleas (Siphonaptera) | publisher=Elsevier | date=2019 | isbn=978-0-12-814043-7 | doi=10.1016/b978-0-12-814043-7.00010-8 | page=145–169}} An eschar develops at the site of the flea bite. Doxycycline is used for treatment of clinical patients.
Fleas are believed to be the likely reservoir of R. felis. R. felis is transmitted transovarially between fleas.
More recently, some authorities have published increasing concerns about the role of more and more species of arthropod vectors of this organism; Rickettsia felis has by now been detected in many arthropods in the wild, including various species of mites, ticks, blood-sucking bugs in the genus Cimex, sucking lice, flea species of various types, both free-living and "sticktight fleas", and various other biting insects.Brown, Lisa D. Macaluso, Kevin R. Rickettsia felis, an Emerging Flea-Borne Rickettsiosis. Curr Trop Med Rep (2016) 3: 27. doi:10.1007/s40475-016-0070-6 In particular there is concern about the prevalence of Rickettsia felis in regions such as parts of sub-Saharan Africa, in mosquito genera such as Anopheles, Aedes, Mansonia, and Culex; all of these genera include species that are challenging to control and have long been recognised as effective vectors of various important human and animal diseases.
The mosquito species Anopheles gambiae, which is notorious mainly as a malaria vector, has been demonstrated to be a competent vector for Rickettsia felis. More unexpectedly, cells of some important disease vector species of mosquitoes in the genus Aedes, which is most commonly seen as a vector for arboviruses, support growth of Rickettsia felis.Parola, Philippe. Musso, Didier. Raoult, Didier. Rickettsia felis: the next mosquito-borne outbreak? The Lancet Infectious Diseases, Volume 16, Issue 10, 1112 - 1113 In addition, in tropical regions where Aedes albopictus and Aedes aegypti are established disease vectors and ectoparasites of humans, patients have tested positive for Rickettsia felis. To some authorities this suggests that Aedes species might be able to infect their hosts with Rickettsia felis, and that patients in, or returning from, the tropics with fevers of unknown origin, should be tested for Rickettsia felis infection. They see as very real, the possibility that Rickettsia felis might be the next mosquito-borne pathogen to emerge as a multi-continental disease outbreak.
Australia
Human cases of Rickettsia felis were diagnosed in Australia in 2009, these were the first reported human infections in Australia.{{cite journal |vauthors=Williams M, Izzard L, Graves SR, Stenos J, Kelly JJ |title=First probable Australian cases of human infection with Rickettsia felis (cat-flea typhus) |journal=Med. J. Aust. |volume=194 |issue=1 |pages=41–3 |date=January 2011 |doi=10.5694/j.1326-5377.2011.tb04145.x |pmid=21449868 |s2cid=22677434 |url=http://www.mja.com.au/public/issues/194_01_030111/wil10168_fm.html|url-access=subscription }}
Diagnosis
Diagnosis of R. felis infection requires specific polymerase chain reaction (PCR) testing to distinguish serological results from R. typhi infection.
References
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External links
- {{cite web |title=Rickettsia felis |work=NCBI Taxonomy Browser |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=42862 |id=42862}}
{{Gram-negative proteobacterial diseases}}
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