Ehrlichia ruminantium: Difference between revisions
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[[File:Ehrlichia-ruminantium-sheep-brain.jpg|thumb|Ehrlichia ruminantium bacteria within the brain of sheep that died in Africa|225x225px]] |
[[File:Ehrlichia-ruminantium-sheep-brain.jpg|thumb|Ehrlichia ruminantium bacteria within the brain of sheep that died in Africa|225x225px]] |
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'''Heartwater''' (also known as '''cowdriosis''', '''nintas, and ehrlichiosis''') is a tick-borne [[rickettsia]]l disease of domestic and wild ruminants, common host animals include sheep, goats, cattle, and some deer.<ref>{{cite journal | vauthors = Peter TF, Burridge MJ, Mahan SM | title = Ehrlichia ruminantium infection (heartwater) in wild animals | journal = Trends in Parasitology | volume = 18 | issue = 5 | pages = 214–8 | date = May 2002 | pmid = 11983602 | doi = 10.1016/s1471-4922(02)02251-1 }}</ref> It is caused by '''''[[Ehrlichia ruminantium]]''''' (formerly ''Cowdria ruminantium'')<!--<ref>http://www.ebi.ac.uk/2can/genomes/bacteria/Ehrlichia_ruminantium.html</ref> --> - an intracellular [[Gram-negative]] coccal bacterium (also referred to as ''Rickettsia ruminantium''). The disease is spread by various [[Amblyomma]] ticks. Affected [[mammal]]s include [[cattle]], [[sheep]], [[goat]]s, [[antelope]], and [[African buffalo|buffalo]], but the disease has the biggest economic impact on cattle production in affected areas. The disease's name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals.<ref name="APHIS">{{cite web |title=Heartwater |url=http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahheartw.html |url-status=dead |archive-url=https://web.archive.org/web/20080413224051/http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahheartw.html |archive-date=2008-04-13 |access-date=2008-04-13 |work=Animal and Plant Health Inspection Service |publisher=U.S. Department of Agriculture}}</ref> There are reports of [[Zoonosis|zoonotic infections]] of humans by ''E. ruminantium'', like for other ''Ehrlichia'' species, such as those that cause human [[ehrlichiosis]].<ref>{{cite journal |vauthors=Allsopp MT, Louw M, Meyer EC |date=December 2005 |title=Ehrlichia ruminantium: an emerging human pathogen? |url=http://doi.wiley.com/10.1196/annals.1355.060 |journal=Annals of the New York Academy of Sciences |volume=1063 |issue=1 |pages=358–60 |bibcode=2005NYASA1063..358A |doi=10.1196/annals.1355.060 |pmid=16481543 |s2cid=35037984}}</ref><ref>{{cite journal |vauthors=Gaddy HG |date=August 2020 |title=Using local knowledge in emerging infectious disease research |url= |journal=Social Science & Medicine |volume=258 |pages=113107 |doi=10.1016/j.socscimed.2020.113107 |pmc=7292947 |pmid=32563166}}</ref><ref>{{cite journal |vauthors=Esemu SN, Ndip LM, Ndip RN |date=2011-01-01 |title=Ehrlichia species, probable emerging human pathogens in sub-Saharan Africa: environmental exacerbation |url=https://www.degruyter.com/doi/10.1515/REVEH.2011.034 |journal=Reviews on Environmental Health |volume=26 |issue=4 |pages=269–79 |doi=10.1515/REVEH.2011.034 |pmid=22435325 |s2cid=26448157}}</ref> |
'''Heartwater''' (also known as '''cowdriosis''', '''nintas, and ehrlichiosis''') is a tick-borne [[rickettsia]]l disease of domestic and wild ruminants, common host animals include sheep, goats, cattle, and some deer.<ref>{{cite journal | vauthors = Peter TF, Burridge MJ, Mahan SM | title = Ehrlichia ruminantium infection (heartwater) in wild animals | journal = Trends in Parasitology | volume = 18 | issue = 5 | pages = 214–8 | date = May 2002 | pmid = 11983602 | doi = 10.1016/s1471-4922(02)02251-1 }}</ref> It is caused by '''''[[Ehrlichia ruminantium]]''''' (formerly ''Cowdria ruminantium'')<!--<ref>http://www.ebi.ac.uk/2can/genomes/bacteria/Ehrlichia_ruminantium.html</ref> --> - an intracellular [[Gram-negative]] coccal bacterium (also referred to as ''Rickettsia ruminantium''). The disease is spread by various [[Amblyomma]] ticks. Affected [[mammal]]s include [[cattle]], [[sheep]], [[goat]]s, [[antelope]], and [[African buffalo|buffalo]], but the disease has the biggest economic impact on cattle production in affected areas. The disease's name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals.<ref name="APHIS">{{cite web |title=Heartwater |url=http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahheartw.html |url-status=dead |archive-url=https://web.archive.org/web/20080413224051/http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahheartw.html |archive-date=2008-04-13 |access-date=2008-04-13 |work=Animal and Plant Health Inspection Service |publisher=U.S. Department of Agriculture}}</ref> There are reports of [[Zoonosis|zoonotic infections]] of humans by ''E. ruminantium'', like for other ''Ehrlichia'' species, such as those that cause human [[ehrlichiosis]].<ref>{{cite journal |vauthors=Allsopp MT, Louw M, Meyer EC |date=December 2005 |title=Ehrlichia ruminantium: an emerging human pathogen? |url=http://doi.wiley.com/10.1196/annals.1355.060 |journal=Annals of the New York Academy of Sciences |volume=1063 |issue=1 |pages=358–60 |bibcode=2005NYASA1063..358A |doi=10.1196/annals.1355.060 |pmid=16481543 |s2cid=35037984}}</ref><ref>{{cite journal |vauthors=Gaddy HG |date=August 2020 |title=Using local knowledge in emerging infectious disease research |url= |journal=Social Science & Medicine |volume=258 |pages=113107 |doi=10.1016/j.socscimed.2020.113107 |pmc=7292947 |pmid=32563166}}</ref><ref>{{cite journal |vauthors=Esemu SN, Ndip LM, Ndip RN |date=2011-01-01 |title=Ehrlichia species, probable emerging human pathogens in sub-Saharan Africa: environmental exacerbation |url=https://www.degruyter.com/doi/10.1515/REVEH.2011.034 |journal=Reviews on Environmental Health |volume=26 |issue=4 |pages=269–79 |doi=10.1515/REVEH.2011.034 |pmid=22435325 |s2cid=26448157}}</ref> |
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== History == |
== History == |
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Revision as of 17:50, 10 July 2022
| Heartwater | |
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| Amblyomma hebraeum, a vector of heartwater disease | |
| Scientific classification | |
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| Order: | |
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| Genus: | Ehrlichia
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| Species: | E. ruminantium [1]
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| Binomial name | |
| Ehrlichia ruminantium (Dumler, 2001)
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| Synonyms | |
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Heartwater (also known as cowdriosis, nintas, and ehrlichiosis) is a tick-borne rickettsial disease of domestic and wild ruminants, common host animals include sheep, goats, cattle, and some deer.[2] It is caused by Ehrlichia ruminantium (formerly Cowdria ruminantium) - an intracellular Gram-negative coccal bacterium (also referred to as Rickettsia ruminantium). The disease is spread by various Amblyomma ticks. Affected mammals include cattle, sheep, goats, antelope, and buffalo, but the disease has the biggest economic impact on cattle production in affected areas. The disease's name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals.[3] There are reports of zoonotic infections of humans by E. ruminantium, like for other Ehrlichia species, such as those that cause human ehrlichiosis.[4][5][6]
History
Heartwater disease was first described in 1838 within the personal journal of Louis Trichardt, a Voortrekker in South Africa. In Trichardt's notes he recorded that a majority of the surrounding sheep died approximately three weeks after a large tick infestation was observed.[7]
Distribution
The disease is common in sub-Saharan Africa and some of the West Indian islands. It was first identified in South Africa in the 1838, and had reached the Caribbean by 1980.[3] The ticks that carry the disease occur in Africa and the Caribbean, and feed on a wide variety of vertebrate hosts. In the Caribbean, at least, the cattle egret has been implicated in the spread of heartwater, since it colonized the islands in the 1950s.[3] Animals often acquire the disease when moved onto pastures where infected ticks are found.
Hosts
Nearly all members of Bovidae are susceptible to this disease, but vary in their susceptibility, Zubu and Water buffalo appearing to be most resistant.[8] The most susceptible species to heartwater appears to be the various goats.[9][10][11] The South African buffalo, bleskbok, black wildebeest, helmeted guinea fowl, leopard tortoise and scrub hare are known to host heartwater without symptoms and act as a tick reservoir.[12]
Experimental hosts
In laboratory experiments non-ruminants such as ferrets, laboratory mice, and four-striped grass mice have demonstrated susceptibility to the disease.
Clinical signs
Clinical disease is more common in young animals and non-native breeds. The clinical signs of disease are caused by an increased vascular permeability and consequent oedema and hypovolemia.
The symptoms include neurological signs such as tremors and head pressing, respiratory signs such as coughing and nasal discharge, and systemic signs such as fever and loss of appetite. Physical examination may reveal petechiae of the mucous membranes, tachycardia, and muffled heart sounds. Cowdriosis can also cause reproductive and gastrointestinal disease. It is frequently fatal.
Diagnosis
On post mortem examination, a light yellow transudate that coagulates on exposure to air is often found within the thorax, pericardium, and abdomen. Most fatal cases have the hydropericardium that gives the disease its common name. Pulmonary oedema and mucosal congestion are regularly seen along with frothy fluid in the airways and cut surfaces of the lungs.
To definitively diagnose the disease, C. ruminantium must be demonstrated either in preparations of the hippocampus under Giemsa staining or by histopathology of brain or kidney.
Treatment and control
During the early stages of disease, animals may be treated with sulfonamides and tetracyclines. In advanced disease, prognosis is poor. Tetracyclines can also be used prophylactically when animals are introduced into an area endemic with heartwater. Ectoparasiticides, used as dips, can be used to reduce exposure the animals exposure to bont ticks. In areas endemic for heartwater, the use of dips against other ticks of domestic animals, such as Rhipicephalus (Boophilus) and Hyalomma species is likely, and this will usually contribute to control of vectors of E. ruminantium.
Vaccines
A live blood vaccine is available for protection of young stock, but animals may require treatment for the disease after vaccination.
Several experimental vaccines are currently being developed, examples include attenuated, recombinant and multi-epitope DNA vaccines.[9][13]
Global status
Heartwater is notifiable to the World Organisation for Animal Health.
See also
References
- ^ Dumler JS, Barbet AF, Bekker CP, Dasch GA, Palmer GH, Ray SC, et al. (November 2001). "Reorganization of genera in the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia and Ehrlichia with Neorickettsia, descriptions of six new species combinations and designation of Ehrlichia equi and 'HGE agent' as subjective synonyms of Ehrlichia phagocytophila". International Journal of Systematic and Evolutionary Microbiology. 51 (Pt 6): 2145–2165. doi:10.1099/00207713-51-6-2145. PMID 11760958.
- ^ Peter TF, Burridge MJ, Mahan SM (May 2002). "Ehrlichia ruminantium infection (heartwater) in wild animals". Trends in Parasitology. 18 (5): 214–8. doi:10.1016/s1471-4922(02)02251-1. PMID 11983602.
- ^ a b c "Heartwater". Animal and Plant Health Inspection Service. U.S. Department of Agriculture. Archived from the original on 2008-04-13. Retrieved 2008-04-13.
- ^ Allsopp MT, Louw M, Meyer EC (December 2005). "Ehrlichia ruminantium: an emerging human pathogen?". Annals of the New York Academy of Sciences. 1063 (1): 358–60. Bibcode:2005NYASA1063..358A. doi:10.1196/annals.1355.060. PMID 16481543. S2CID 35037984.
- ^ Gaddy HG (August 2020). "Using local knowledge in emerging infectious disease research". Social Science & Medicine. 258: 113107. doi:10.1016/j.socscimed.2020.113107. PMC 7292947. PMID 32563166.
- ^ Esemu SN, Ndip LM, Ndip RN (2011-01-01). "Ehrlichia species, probable emerging human pathogens in sub-Saharan Africa: environmental exacerbation". Reviews on Environmental Health. 26 (4): 269–79. doi:10.1515/REVEH.2011.034. PMID 22435325. S2CID 26448157.
- ^ "Heartwater in Sheep and Goats". The Veterinary Journal (1900). 55 (9): 157–161. 1902. doi:10.1016/s0372-5545(17)72105-0. ISSN 0372-5545.
- ^ Pfukenyi, Davies M.; Mukaratirwa, Samson (2018-10-18). "Amphistome infections in domestic and wild ruminants in East and Southern Africa: A review". Onderstepoort Journal of Veterinary Research. 85 (1). doi:10.4102/ojvr.v85i1.1584. ISSN 2219-0635.
- ^ a b Zweygarth, Erich; Josemans, Antoinette I.; Steyn, Helena C. (2008). "Experimental use of the attenuated Ehrlichia ruminantium (Welgevonden) vaccine in Merino sheep and Angora goats". Vaccine. 26: G34–G39. doi:10.1016/j.vaccine.2008.09.068.
- ^ Leask, Rhoda; Pettey, Kenneth P.; Bath, Gareth F. (2013-10-23). "An afebrile heartwater-like syndrome in goats". Journal of the South African Veterinary Association. 84 (1). doi:10.4102/jsava.v84i1.955. ISSN 2224-9435.
- ^ Ahmadu, B.; Lovelace, C.E.A.; Mahan, S. (2004-11-08). "Some observations on the sero-prevalence of heartwater and tick infestation in Zambian goats : research communication". Onderstepoort J Vet Res. 71 (2). doi:10.4102/ojvr.v71i2.279. ISSN 2219-0635.
- ^ "Tick Biolgy and Control. ed. G.B. Whitehead and J.D. Gibson. 222 pages. Proceedings of an International Conference held in January 1981 under the auspices of the Tick Research Unit, Rhodes University, Grahamstown, South Africa. ISBN 0 86810 047 1. Tick Research Unit, Rhodes University, Grahamstown, South Africa, 1982". Parasitology. 85 (3): 616–616. 1982. doi:10.1017/s0031182000056420. ISSN 0031-1820.
- ^ COLLINS, NICOLA E.; PRETORIUS, ALRI; KLEEF, MIRINDA; BRAYTON, KELLY A.; ZWEYGARTH, ERICH; ALLSOPP, BASIL A. (2003). "Development of Improved Vaccines for Heartwater". Annals of the New York Academy of Sciences. 990 (1): 474–484. doi:10.1111/j.1749-6632.2003.tb07413.x. ISSN 0077-8923.
Additional references
- "Heartwater" (PDF). Center for Food Security and Public Health. Iowa State University. 2015.
- "Heartwater - Cowdriosis" (PDF). World Organisation for Animal Health (OIE). 2009.