Neorickettsia risticii

Neorickettsia risticii
Neorickettsia risticii phylogenetic tree based on 16S rRNA gene sequences
Scientific classification
Domain:
Bacteria
Phylum:
Pseudomonadota
Class:
Alphaproteobacteria
Order:
Rickettsiales
Family:
Ehrlichiaceae
Genus:
Neorickettsia
Species:
N. risticii
Binomial name
Neorickettsia risticii (Dumler et al., 2001)
Synonyms

Ehrlichia risticii

Neorickettsia risticii, formerly Ehrlichia risticii, is an obligate intracellular gram negative bacteria that typically lives as an endosymbiont in parasitic flatworms, specifically flukes.[1] N. risticii is the known causative agent of equine neorickettsiosis (also known as Potomac horse fever (PHF)),[2] which gets its name from its discovery near the Potomac River in Maryland and Virginia.[3] N. risticii was first recovered from horses in this region in 1984 but was not recognized as the causative agent of PHF until 1979.[3] Potomac horse fever is currently endemic in the United States but has also been reported with lower frequency in other regions, including Canada, Brazil, Uruguay, and Europe.[4] PHF is a condition that is clinically important for horses since it can cause serious signs such as fever, diarrhea, colic, and laminitis.[5] PHF has a fatality rate of approximately 30%, making this condition one of the concerns for horse owners in endemic regions[5] N. risticii is typically acquired in the middle to late summer near freshwater streams or rivers, as well as on irrigated pastures.[6] This is a seasonal infection because it relies on the ingestion of an arthropod vector, which is more commonly found on pasture in the summer months.[7] Although N. risticii is a well known causative agent for PHF in horses, it may act as a potential pathogen in cats and dogs as well.[8] Not only has N. risticii been successfully cultured from monocytes of dogs and cats,[6] but cats have become clinically ill after experimental infection with the bacteria.[9] In addition, N. risticii has been isolated and cultured from human histiocytic lymphoma cells.[6]

  1. ^ Teymournejad O, Lin M, Bekebrede H, Kamr A, Toribio RE, Arroyo LG, et al. (February 2020). "Neorickettsia Species That Causes Potomac Horse Fever". mBio. 11 (1) (published 25 February 2020). doi:10.1128/mBio.03429-19. ISSN 2150-7511. PMC 7042704. PMID 32098825. Wikidata Q89881646. (erratum)
  2. ^ Gibson KE, Rikihisa Y, Zhang C, Martin C (February 2005). "Neorickettsia risticii is vertically transmitted in the trematode Acanthatrium oregonense and horizontally transmitted to bats". Environmental Microbiology. 7 (2): 203–12. Bibcode:2005EnvMi...7..203G. doi:10.1111/j.1462-2920.2004.00683.x. PMID 15658987.
  3. ^ a b Chaichanasiriwithaya W, Rikihisa Y, Yamamoto S, Reed S, Crawford TB, Perryman LE, Palmer GH (December 1994). "Antigenic, morphologic, and molecular characterization of new Ehrlichia risticii isolates". Journal of Clinical Microbiology. 32 (12): 3026–33. doi:10.1128/JCM.32.12.3026-3033.1994. PMC 264219. PMID 7533780.
  4. ^ Xiong Q, Bekebrede H, Sharma P, Arroyo LG, Baird JD, Rikihisa Y (October 2016). Dozois CM (ed.). "An Ecotype of Neorickettsia risticii Causing Potomac Horse Fever in Canada". Applied and Environmental Microbiology. 82 (19): 6030–6. Bibcode:2016ApEnM..82.6030X. doi:10.1128/AEM.01366-16. PMC 5038023. PMID 27474720.
  5. ^ a b Cite error: The named reference Roier_2016 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Pusterla_2014 was invoked but never defined (see the help page).
  7. ^ McLaughlin B, Gough J (June 1996). "Potomac horse fever in southwestern Ontario". The Canadian Veterinary Journal. 37 (6): 367–8. PMC 1576412. PMID 8689598.
  8. ^ Ayllón T, Diniz PP, Breitschwerdt EB, Villaescusa A, Rodríguez-Franco F, Sainz A (February 2012). "Vector-borne diseases in client-owned and stray cats from Madrid, Spain". Vector Borne and Zoonotic Diseases. 12 (2): 143–50. doi:10.1089/vbz.2011.0729. PMID 22022820.
  9. ^ Lappin MR, Griffin B, Brunt J, Riley A, Burney D, Hawley J, et al. (April 2006). "Prevalence of Bartonella species, haemoplasma species, Ehrlichia species, Anaplasma phagocytophilum, and Neorickettsia risticii DNA in the blood of cats and their fleas in the United States". Journal of Feline Medicine and Surgery. 8 (2): 85–90. doi:10.1016/j.jfms.2005.08.003. PMC 10832684. PMID 16290092. S2CID 19187668.