Rickettsia typhi

Rickettsia typhi is a small, aerobic, obligate intracellular, rod shaped gram negative bacterium.[1] It belongs to the typhus group of the Rickettsia genus, along with R. prowazekii.[2] R. typhi has an uncertain history, as it may have long gone shadowed by epidemic typhus (R. prowazekii).[3] This bacterium is recognized as a biocontainment level 2/3 organism.[1][4] 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.[3] 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.[5][6] 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.[7]

R. typhi was once one of the most prevalent causes of rickettsial diseases worldwide, but has since experienced a drop in case reports with the implementation of pest control programs.[8][9][10] The microorganism is concentrated in warmer climate and coastal ports where there is an abundance of rats and their fleas, which are the preferred hosts for the pathogen.[8][9] R. typhi  is transmitted between competent flea and mammalian hosts through flea bites and contact with infected feces and tissues.[8][11]

There are several laboratory tests available for the diagnosis of Rickettsial species, with the traditional diagnosis based on serology.[8] However, newer laboratory techniques such as real-time PCR and microimmunofluorescence can be used to identify Rickettsia faster and down to the Rickettsia typhi species level.[9]

Rickettsia typhi
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Pseudomonadota
Class: Alphaproteobacteria
Order: Rickettsiales
Family: Rickettsiaceae
Genus: Rickettsia
Species group: Typhus group
Species:
R. typhi
Binomial name
Rickettsia typhi
(Wolbach and Todd, 1920) Philip, 1943
  1. ^ a b McLeod, Michael P.; Qin, Xiang; Karpathy, Sandor E.; Gioia, Jason; Highlander, Sarah K.; Fox, George E.; McNeill, Thomas Z.; Jiang, Huaiyang; Muzny, Donna; Jacob, Leni S.; Hawes, Alicia C. (2004-09-01). "Complete Genome Sequence of Rickettsia typhi and Comparison with Sequences of Other Rickettsiae". Journal of Bacteriology. 186 (17): 5842–5855. doi:10.1128/JB.186.17.5842-5855.2004. ISSN 0021-9193. PMC 516817. PMID 15317790.
  2. ^ Mansueto, Pasquale; Vitale, Giustina; Cascio, Antonio; Seidita, Aurelio; Pepe, Ilenia; Carroccio, Antonio; di Rosa, Salvatore; Rini, Giovam Battista; Cillari, Enrico (2011-09-06). "New Insight into Immunity and Immunopathology of Rickettsial Diseases". Clinical and Developmental Immunology. 2012: 967852. doi:10.1155/2012/967852. PMC 3170826. PMID 21912565.
  3. ^ a b Azad, A. F.; Traub, R. (October 1989). "Experimental transmission of murine typhus by Xenopsylla cheopis flea bites". Medical and Veterinary Entomology. 3 (4): 429–433. doi:10.1111/j.1365-2915.1989.tb00251.x. ISSN 0269-283X. PMID 2519693. S2CID 24176171.
  4. ^ Rauch, Jessica; Eisermann, Philip; Noack, Bernd; Mehlhoop, Ute; Muntau, Birgit; Schäfer, Johannes; Tappe, Dennis (July 2018). "Typhus Group Rickettsiosis, Germany, 2010–20171". Emerging Infectious Diseases. 24 (7): 1213–1220. doi:10.3201/eid2407.180093. ISSN 1080-6040. PMC 6038764. PMID 29912688.
  5. ^ Schriefer, M E; Sacci, J B; Dumler, J S; Bullen, M G; Azad, A F (1994). "Identification of a novel rickettsial infection in a patient diagnosed with murine typhus". Journal of Clinical Microbiology. 32 (4): 949–954. doi:10.1128/jcm.32.4.949-954.1994. ISSN 0095-1137. PMC 267160. PMID 8027348.
  6. ^ Scola, B. La; Raoult, D. (1997-11-01). "Laboratory diagnosis of rickettsioses: current approaches to diagnosis of old and new rickettsial diseases". Journal of Clinical Microbiology. 35 (11): 2715–2727. doi:10.1128/jcm.35.11.2715-2727.1997. ISSN 0095-1137. PMC 230049. PMID 9350721.
  7. ^ Sahni, Sanjeev K; Rydkina, Elena (2009-03-30). "Host-cell interactions with pathogenic Rickettsia species". Future Microbiology. 4 (3): 323–339. doi:10.2217/fmb.09.6. ISSN 1746-0913. PMC 2775711. PMID 19327117.
  8. ^ a b c d Eremeeva, Marina E.; Dasch, Gregory A. (2012-01-01), Long, Sarah S. (ed.), "179 - Other Rickettsia Species", Principles and Practice of Pediatric Infectious Diseases (Fourth Edition), London: Content Repository Only!, pp. 930–938.e4, ISBN 978-1-4377-2702-9, retrieved 2020-10-06
  9. ^ a b c Whiteford, Sarah F.; Taylor, Jeffery P.; Dumler, J. Stephen (2001-03-01). "Clinical, Laboratory, and Epidemiologic Features of Murine Typhus in 97 Texas Children". Archives of Pediatrics & Adolescent Medicine. 155 (3): 396–400. doi:10.1001/archpedi.155.3.396. ISSN 1072-4710. PMID 11231808.
  10. ^ Schriefer, M. E.; Sacci, J. B.; Dumler, J. S.; Bullen, M. G.; Azad, A. F. (1994-04-01). "Identification of a novel rickettsial infection in a patient diagnosed with murine typhus". Journal of Clinical Microbiology. 32 (4): 949–954. doi:10.1128/JCM.32.4.949-954.1994. ISSN 0095-1137. PMC 267160. PMID 8027348.
  11. ^ Abdad, Mohammad Yazid; Abdallah, Rita Abou; Fournier, Pierre-Edouard; Stenos, John; Vasoo, Shawn (2018-08-01). "A Concise Review of the Epidemiology and Diagnostics of Rickettsioses: Rickettsia and Orientia spp". Journal of Clinical Microbiology. 56 (8). doi:10.1128/JCM.01728-17. ISSN 0095-1137. PMC 6062794. PMID 29769278.