Editing Rift Valley fever

{{short description|Human and livestock viral disease}}
{{cs1 config|name-list-style=vanc}}
{{Infobox medical condition (new)
| name = Rift Valley fever
| image = Rift Valley fever tissue.jpg
| image_size = 250px
| caption = [[Transmission electron microscopy|TEM]] [[micrograph]] of tissue infected with Rift Valley fever virus
| symptoms = [[Fever]], [[Myalgia|muscle pains]], [[headache]]s
| complications = Loss of sight, [[confusion]], bleeding, [[liver problems]]
| onset = 
| duration = Up to a week
| types = 
| causes = ''[[Phlebovirus]]'' spread by an infected animal or [[mosquito]]
| risks = 
| diagnosis = Finding [[antibodies]] or the virus in the blood
| differential = 
| prevention = Vaccinating animals against the disease, decreasing mosquito bites
| treatment = [[Supportive care]]<ref name=WHO2010/>
| medication = 
| prognosis = 
| frequency = Outbreaks in [[Africa]] and [[Arabia]]
| deaths = 
}}
'''Rift Valley fever''' ('''RVF''') is a [[viral disease]] of humans and livestock that can cause mild to severe symptoms. The mild symptoms may include: [[fever]], [[Myalgia|muscle pains]], and [[headache]]s which often last for up to a week. The severe symptoms may include: loss of sight beginning three weeks after the infection, infections of the [[brain]] causing severe headaches and [[confusion]], and bleeding together with [[liver problems]] which may occur within the first few days. Those who have bleeding have a chance of death as high as 50%.

The disease is caused by the RVF [[virus]]. It is spread by either touching infected animal blood, breathing in the air around an infected animal being [[butchered]], drinking [[raw milk]] from an infected animal, or the bite of infected [[mosquito]]es. Animals like cows, sheep, goats, and camels may be affected. In these animals it is spread mostly by mosquitoes.<ref name=WHO2010/> It does not appear that one person can infect another. The disease is diagnosed by finding [[antibodies]] against the virus or the virus itself in the blood.
Prevention of the disease in humans is accomplished by vaccinating animals against the disease. This must be done before an outbreak occurs because if it is done during an outbreak it may worsen the situation. Stopping the movement of animals during an outbreak may also be useful, as may decreasing mosquito numbers and avoiding their bites. There is a human [[vaccine]]; however, as of 2010, it is not widely available. There is no specific treatment and medical efforts are supportive.

[[Epidemics|Outbreaks]] of the disease have only occurred in [[Africa]] and [[Arabia]]. Outbreaks usually occur during periods of increased rain which increases the number of mosquitoes. The disease was first reported among livestock in [[Great Rift Valley, Kenya|Rift Valley]] of [[Kenya]] in the early 1900s,<ref>{{cite book| vauthors = Palmer SR |title=Oxford textbook of zoonoses: biology, clinical practice, and public health control|date=2011|publisher=Oxford Univ. Press|location=Oxford u.a.|isbn=9780198570028|page=423|url=https://books.google.com/books?id=S90mOwgdz9kC&pg=PA423|edition=2nd|url-status=live|archive-url=https://web.archive.org/web/20170908222523/https://books.google.com/books?id=S90mOwgdz9kC&pg=PA423|archive-date=2017-09-08}}</ref> and the virus was first isolated in 1931.<ref name=WHO2010>{{cite web|title=Rift Valley fever|work=Fact sheet N°207|url=https://www.who.int/mediacentre/factsheets/fs207/en/|publisher=World Health Organization|access-date=21 March 2014|date=May 2010|url-status=live|archive-url=https://web.archive.org/web/20140415092827/http://www.who.int/mediacentre/factsheets/fs207/en/|archive-date=15 April 2014}}</ref>

==Signs and symptoms==
In humans, the virus can cause several syndromes. Usually, they have either no symptoms or only a mild illness with fever, [[headache]], [[myalgia|muscle pains]], and [[liver]] abnormalities. In a small percentage of cases (< 2%), the illness can progress to [[hemorrhagic fever]] syndrome, [[meningoencephalitis]] (inflammation of the brain and [[meninges|tissues lining the brain]]), or affect the eye. Patients who become ill usually experience fever, generalised weakness, back pain, dizziness, and weight loss at the onset of the illness. Typically, people recover within two to seven days after onset. About 1% of people with the disease die of it. In livestock, the fatality level is significantly higher. Pregnant livestock infected with RVF [[abortion|abort]] virtually 100% of foetuses. An [[epizootic]] (animal disease epidemic) of RVF is usually first indicated by a wave of unexplained abortions.{{Citation needed|date=July 2020}}

Other signs in livestock include vomiting and diarrhea, respiratory disease, fever, lethargy, anorexia, and sudden death in young animals.<ref name="WikiVet">[http://en.wikivet.net/Rift_Valley_Fever Rift Valley Fever] {{webarchive|url=https://web.archive.org/web/20120508121622/http://en.wikivet.net/Rift_Valley_Fever |date=2012-05-08 }} reviewed and published by [[WikiVet]], accessed 12 October 2011.</ref>

==Cause==

===Virology===
{{Virusbox
| name = Rift Valley fever virus
| image = Viruses-08-00174-g001.png
| image_alt = Prototypic phlebovirus virion and genome organization
| image_caption = [[Phlebovirus]] virion and genome
| parent = Phlebovirus
| species = Phlebovirus riftense
| synonyms = * ''Rify Valley fever phlebovirus''
| synonyms_ref = <ref>{{cite web|title=History of the taxon: Species: ''Phlebovirus riftense'' (2024 Release, MSL #40)|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=202400163&taxon_name=Phlebovirus%20riftense|publisher=International Committee on Taxonomy of Viruses|access-date=19 March 2025}}</ref>
}}

The virus belongs to the ''[[Bunyaviricetes]]'' class. This is a class of enveloped negative single-stranded RNA viruses. All bunyaviruses have an outer lipid envelope with two [[glycoproteins]]—G(N) and G(C)—required for cell entry. They deliver their genome into the host-cell [[cytoplasm]] by fusing their envelope with an [[endosomal membrane]].{{Citation needed|date=July 2020}}

The virus' G(C) protein has a class II [[membrane fusion protein]] architecture similar to that found in [[flavivirus]]es and [[alphavirus]]es.<ref name=Dessau2013>{{cite journal | vauthors = Dessau M, Modis Y | title = Crystal structure of glycoprotein C from Rift Valley fever virus | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 110 | issue = 5 | pages = 1696–701 | date = January 2013 | pmid = 23319635 | pmc = 3562824 | doi = 10.1073/pnas.1217780110 | bibcode = 2013PNAS..110.1696D | doi-access = free }}</ref> This structural similarity suggests that there may be a common origin for these viral families.{{citation needed|date=May 2021}}

The virus' 11.5 [[Kilo-base pair|kb]] tripartite [[genome]] is composed of single-stranded [[RNA]]. As a ''[[Phlebovirus]],'' it has an [[Sense (molecular biology)|ambisense]] genome. Its L and M segments are negative-sense, but its S segment is ambisense.<ref>{{cite web|url=http://viralzone.expasy.org/all_by_species/252.html|title=ViralZone: Phlebovirus|website=viralzone.expasy.org|access-date=2016-09-14|url-status=live|archive-url=https://web.archive.org/web/20161003114115/http://viralzone.expasy.org/all_by_species/252.html|archive-date=2016-10-03}}</ref> These three genome segments code for six major proteins: L protein ([[Polymerase|viral polymerase]]), the two glycoproteins G(N) and G(C), the [[Capsid|nucleocapsid]] N protein, and the [[Bunyaviridae nonstructural S proteins|nonstructural NSs]] and NSm proteins.<ref>{{cite journal |last1=Bird |first1=Brian H. |last2=Khristova |first2=Marina L. |last3=Rollin |first3=Pierre E. |last4=Ksiazek |first4=Thomas G. |last5=Nichol |first5=Stuart T. |date=2007-03-15 |title=Complete Genome Analysis of 33 Ecologically and Biologically Diverse Rift Valley Fever Virus Strains Reveals Widespread Virus Movement and Low Genetic Diversity due to Recent Common Ancestry |journal=Journal of Virology |language=en |volume=81 |issue=6 |pages=2805–2816 |doi=10.1128/JVI.02095-06 |issn=0022-538X |pmc=1865992 |pmid=17192303}}</ref>

===Transmission===
{{See also|Prevention of viral hemorrhagic fever}}
The virus is transmitted through mosquito [[Vector (epidemiology)|vectors]], as well as through contact with the tissue of infected animals. Two species—''[[Culex tritaeniorhynchus]]'' and ''[[Aedes vexans]]''—are known to transmit the virus.<ref>{{cite journal | vauthors = Jupp PG, Kemp A, Grobbelaar A, Lema P, Burt FJ, Alahmed AM, Al Mujalli D, Al Khamees M, Swanepoel R | title = The 2000 epidemic of Rift Valley fever in Saudi Arabia: mosquito vector studies | journal = Medical and Veterinary Entomology | volume = 16 | issue = 3 | pages = 245–52 | date = September 2002 | pmid = 12243225 | doi = 10.1046/j.1365-2915.2002.00371.x | doi-access = free }}</ref> Other potential vectors include ''[[Aedes caspius]]'', ''[[Aedes mcintosh]]'', ''[[Aedes ochraceus]],'' ''[[Culex pipiens]]'', ''[[Culex antennatus]]'', ''[[Culex perexiguus]]'', ''[[Culex zombaensis]]'' and ''[[Culex quinquefasciatus]]''.<ref>{{cite journal | vauthors = Turell MJ, Presley SM, Gad AM, Cope SE, Dohm DJ, Morrill JC, Arthur RR | title = Vector competence of Egyptian mosquitoes for Rift Valley fever virus | journal = The American Journal of Tropical Medicine and Hygiene | volume = 54 | issue = 2 | pages = 136–39 | date = February 1996 | pmid = 8619436 | doi = 10.4269/ajtmh.1996.54.136 }}</ref><ref>{{cite journal | vauthors = Turell MJ, Lee JS, Richardson JH, Sang RC, Kioko EN, Agawo MO, Pecor J, O'Guinn ML | s2cid = 36591701 | title = Vector competence of Kenyan Culex zombaensis and Culex quinquefasciatus mosquitoes for Rift Valley fever virus | journal = Journal of the American Mosquito Control Association | volume = 23 | issue = 4 | pages = 378–82 | date = December 2007 | pmid = 18240513 | doi = 10.2987/5645.1 }}</ref><ref>{{cite journal | vauthors = Fontenille D, Traore-Lamizana M, Diallo M, Thonnon J, Digoutte JP, Zeller HG | title = New vectors of Rift Valley fever in West Africa | journal = Emerging Infectious Diseases | volume = 4 | issue = 2 | pages = 289–93 | year = 1998 | pmid = 9621201 | pmc = 2640145 | doi = 10.3201/eid0402.980218 }}</ref> Contact with infected tissue is considered to be the main source of human infections.<ref>{{cite book | vauthors = Swanepoel R, Coetzer JA |chapter=Rift Valley fever | veditors = Coetzer JA, Tustin RC |title=Infectious diseases of livestock |publisher=Oxford University Press Southern Africa |location=Cape Town |year=2004 |pages=1037–70 |isbn=978-0195761702 |edition=2nd}}</ref> The virus has been isolated from two bat species: the [[Peters's Dwarf Epauletted Fruit Bat|Peter's epauletted fruit bat]] (''Micropteropus pusillus'') and the [[Aba Roundleaf Bat|aba roundleaf bat]] (''Hipposideros abae''), which are believed to be [[Natural reservoir|reservoirs]] for the virus.<ref name=isolation>{{cite journal | vauthors = Boiro I, Konstaninov OK, Numerov AD | title = [Isolation of Rift Valley fever virus from bats in the Republic of Guinea] | language = fr | journal = Bulletin de la Société de Pathologie Exotique et de Ses Filiales | volume = 80 | issue = 1 | pages = 62–67 | year = 1987 | pmid = 3607999 }}</ref>

== Pathogenesis ==
Although many components of the RVFV's RNA play an important role in the virus' pathology, the nonstructural protein encoded on the S segment (NSs) is the only component that has been found to directly affect the host. NSs is hostile and combative against the host interferon (IFNs) antiviral response.<ref name=":0">{{cite journal | vauthors = Boshra H, Lorenzo G, Busquets N, Brun A | title = Rift valley fever: recent insights into pathogenesis and prevention | journal = Journal of Virology | volume = 85 | issue = 13 | pages = 6098–105 | date = July 2011 | pmid = 21450816 | pmc = 3126526 | doi = 10.1128/JVI.02641-10 }}</ref> IFNs are essential for the immune system to fight off viral infections in a host.<ref>{{cite journal | vauthors = Fensterl V, Sen GC | title = Interferons and viral infections | journal = BioFactors | volume = 35 | issue = 1 | pages = 14–20 | date = 2009-01-01 | pmid = 19319841 | doi = 10.1002/biof.6 | s2cid = 27209861 }}</ref> This inhibitory mechanism is believed to be due to several reasons, the first being, competitive inhibition of the formation of the transcription factor.<ref name=":0" /> On this transcription factor, NSs interacts with and binds to a subunit that is needed for RNA polymerase I and II.<ref name=":0" /><ref name=":1">{{cite journal | vauthors = Ikegami T, Makino S | title = The pathogenesis of Rift Valley fever | journal = Viruses | volume = 3 | issue = 5 | pages = 493–519 | date = May 2011 | pmid = 21666766 | pmc = 3111045 | doi = 10.3390/v3050493 | doi-access = free }}</ref> This interaction cause competitive inhibition with another transcription factor component and prevents the assembly process of the transcription factor complex, which results in the suppression of the host antiviral response.<ref name=":0" /><ref name=":1" /> Transcription suppression is believed to be another mechanism of this inhibitory process.<ref name=":0" /> This occurs when an area of NSs interacts with and binds to the host's protein, SAP30 and forms a complex.<ref name=":0" /><ref name=":1" /> This complex causes histone acetylation to regress, which is needed for transcriptional activation of the IFN promoter.<ref name=":1" /> This causes IFN expression to be obstructed. Lastly, NSs has also been known to affect regular activity of double-stranded RNA-dependent protein kinase R. This protein is involved in cellular antiviral responses in the host. When RVFV can enter the host's DNA, NSs forms a filamentous structure in the nucleus. This allows the virus to interact with specific areas of the host's DNA that relates to segregation defects and induction of chromosome continuity. This increases host infectivity and decreases the host's antiviral response.<ref name=":0" />

==Diagnosis==
Diagnosis relies on viral isolation from tissues, or serological testing with an [[ELISA]].<ref name="WikiVet"/> Other methods of diagnosis include [[Nucleic acid test|Nucleic Acid Testing]] (NAT), [[Cell culture assays|cell culture]], and [[Immunoglobulin M|IgM antibody]] assays.<ref>{{cite book|title=Fields Virology, 6th Edition| first1 =  Bernard N | last1 = Fields | first2 = David M | last2 = Knipe | first3 = Peter M | last3 = Howley |publisher= Wolters Kluwer, Lippincott Williams & Wilkins |year=2013|isbn=978-1-4511-0563-6|location=Philadelphia, PA|pages=441}}</ref> As of September 2016, the [[Kenya Medical Research Institute]] (KEMRI) has developed a product called Immunoline, designed to diagnose the disease in humans much faster than in previous methods.<ref>{{cite web|url=http://www.nation.co.ke/news/Kemri-develops-kit-for-rapid-test-of-viral-disease/1056-3370550-12brmvu/|title=Kemri develops kit for rapid test of viral disease|language=en-UK|access-date=2016-09-14|url-status=live|archive-url=https://web.archive.org/web/20160906172824/http://www.nation.co.ke/news/Kemri-develops-kit-for-rapid-test-of-viral-disease/1056-3370550-12brmvu/|archive-date=2016-09-06}}</ref>

==Prevention==

A person's chances of becoming infected can be reduced by taking measures to decrease contact with blood, body fluids, or tissues of infected animals and protect against mosquitoes and other bloodsucking insects. The use of mosquito repellents and bed nets are two effective methods. For persons working with animals in RVF-endemic areas, wearing protective equipment to avoid any exposure to blood or tissues of animals that may potentially be infected is an important protective measure.<ref name="CDC">{{cite web |title=Prevention: Rift Valley Fever {{!}} CDC |url=https://www.cdc.gov/vhf/rvf/prevention/index.html |publisher=US Centers for Disease Control and Prevention |access-date=24 September 2018 |language=en-us}} {{PD-notice}}</ref> Potentially, establishing environmental monitoring and case surveillance systems may aid in the prediction and control of future RVF outbreaks.<ref name="CDC"/>

No [[vaccine]]s are currently available for humans. While vaccines have been developed for humans, it has only been used experimentally for scientific personnel in high-risk environments.<ref name=WHO2010/> Trials of several vaccines, such as NDBR-103 and TSI-GSD 200, are ongoing.<ref>{{cite journal | vauthors = Fawzy M, Helmy YA | title = The One Health Approach is Necessary for the Control of Rift Valley Fever Infections in Egypt: A Comprehensive Review | journal = Viruses | volume = 11 | issue = 2 | pages = 139 | date = February 2019 | pmid = 30736362 | pmc = 6410127 | doi = 10.3390/v11020139 | doi-access = free }}</ref> Different types of vaccines for veterinary use are available. The killed vaccines are impractical in routine animal field vaccination because of the need for multiple injections. Live vaccines require a single injection but are known to cause birth defects and abortions in sheep and induce only low-level protection in cattle. The live-attenuated vaccine, MP-12, has demonstrated promising results in laboratory trials in domesticated animals, but more research is needed before the vaccine can be used in the field. The live-attenuated clone 13 vaccine was recently registered and used in South Africa. Alternative vaccines using molecular recombinant constructs are in development and show promising results.<ref name="CDC" />

A vaccine has been conditionally approved for use in animals in the US.<ref>{{cite journal | vauthors = Ikegami T, Hill TE, Smith JK, Zhang L, Juelich TL, Gong B, Slack OA, Ly HJ, Lokugamage N, Freiberg AN | title = Rift Valley Fever Virus MP-12 Vaccine Is Fully Attenuated by a Combination of Partial Attenuations in the S, M, and L Segments | journal = Journal of Virology | volume = 89 | issue = 14 | pages = 7262–76 | date = July 2015 | pmid = 25948740 | pmc = 4473576 | doi = 10.1128/JVI.00135-15 }}</ref> It has been shown that knockout of the NSs and NSm nonstructural proteins of this virus produces an effective vaccine in sheep as well.<ref>{{cite journal | vauthors = Bird BH, Maartens LH, Campbell S, Erasmus BJ, Erickson BR, Dodd KA, Spiropoulou CF, Cannon D, Drew CP, Knust B, McElroy AK, Khristova ML, Albariño CG, Nichol ST | title = Rift Valley fever virus vaccine lacking the NSs and NSm genes is safe, nonteratogenic, and confers protection from viremia, pyrexia, and abortion following challenge in adult and pregnant sheep | journal = Journal of Virology | volume = 85 | issue = 24 | pages = 12901–09 | date = December 2011 | pmid = 21976656 | pmc = 3233145 | doi = 10.1128/JVI.06046-11 }}</ref>

==Epidemiology==
[[Image:Rift valley fever distribution.jpg|upright=1.4|thumb|Distribution of Rift Valley fever in Africa: Blue, countries with endemic disease and substantial outbreaks of RVF; green, countries known to have some cases, periodic isolation of virus, or serologic evidence of RVF]]{{See also|List of Rift Valley fever outbreaks}}
RVF outbreaks occur across [[sub-Saharan Africa]], with outbreaks occurring elsewhere infrequently. Outbreaks of this disease usually correspond with the warm phases of the EI Niño/Southern Oscillation. During this time there is an increase in rainfall, flooding, and greenness of [[vegetation index]], which leads to an increase in mosquito vectors.<ref>{{cite journal|vauthors=Nanyingi MO, Munyua P, Kiama SG, Muchemi GM, Thumbi SM, Bitek AO, Bett B, Muriithi RM, Njenga MK|date=2015-07-31|title=A systematic review of Rift Valley Fever epidemiology 1931–2014|url=http://www.infectionecologyandepidemiology.net/index.php/iee/article/view/28024|url-status=live|journal=Infection Ecology & Epidemiology|volume=5|issue=1 |pages=28024|doi=10.3402/iee.v5.28024|pmc=4522434|pmid=26234531|bibcode=2015InfEE...528024N |archive-url=https://web.archive.org/web/20161202103017/http://www.infectionecologyandepidemiology.net/index.php/iee/article/view/28024|archive-date=2016-12-02}}</ref> RVFV can be transmitted vertically in mosquitos, meaning that the virus can be passed from the mother to her offspring. During dry conditions, the virus can remain viable for many years in the egg. Mosquitos lay their eggs in water, where they eventually hatch. As water is essential for mosquito eggs to hatch, rainfall and flooding cause an increase in the mosquito population and an increased potential for the virus.<ref>{{cite web|title=Rift Valley Fever {{!}} CDC|url=https://www.cdc.gov/vhf/rvf/|url-status=live|archive-url=https://web.archive.org/web/20161204090852/http://www.cdc.gov/vhf/rvf/|archive-date=2016-12-04|access-date=2016-12-01|website=www.cdc.gov}}</ref>

The first documented outbreak was identified in Kenya in 1931, in sheep, cattle, and humans;<ref>{{cite journal|last1=Daubney|first1=R.|last2=Hudson|first2=J. R.|last3=Garnham|first3=P. C.|date=1931|title=Enzootic hepatitis or rift valley fever. An undescribed virus disease of sheep cattle and man from east africa|url=https://onlinelibrary.wiley.com/doi/abs/10.1002/path.1700340418|journal=The Journal of Pathology and Bacteriology |volume=34|issue=4|pages=545–79|doi=10.1002/path.1700340418}}</ref> another severe outbreak in the country in 1950–1951 involved 100,000 deaths in livestock and an unrecorded number of humans with fever.<ref>{{cite journal|last1=Murithi|first1=R. M.|last2=Munyua|first2=P.|last3=Ithondeka|first3=P. M.|last4=Macharia|first4=J. M.|last5=Hightower|first5=A.|last6=Luman|first6=E. T.|last7=Breiman|first7=R. F.|last8=Njenga|first8=M. Kariuki|date=March 2011|title=Rift Valley fever in Kenya: history of epizootics and identification of vulnerable districts|journal=Epidemiology and Infection|volume=139|issue=3|pages=372–80|doi=10.1017/S0950268810001020|pmid=20478084|s2cid=41617078|doi-access=free}}</ref> An outbreak occurred in South Africa in 1974–1976, with more than 500,000 infected animals and the first deaths in humans.<ref>{{cite journal|last1=McMillen|first1=Cynthia M.|last2=Hartman|first2=Amy L.|date=2018|title=Rift Valley fever in animals and humans: Current perspectives|journal=Antiviral Research|volume=156|pages=29–37|doi=10.1016/j.antiviral.2018.05.009|pmid=29857007|s2cid=46918400|pmc=10316118}}</ref><ref>{{cite journal|last1=van Velden|first1=D. J.|last2=Meyer|first2=J. D.|last3=Olivier|first3=J.|last4=Gear|first4=J. H.|last5=McIntosh|first5=B.|date=1977-06-11|title=Rift Valley fever affecting humans in South Africa: a clinicopathological study|url=https://pubmed.ncbi.nlm.nih.gov/561445/|journal=South African Medical Journal = Suid-Afrikaanse Tydskrif vir Geneeskunde|volume=51|issue=24|pages=867–71|pmid=561445}}</ref> In [[Egypt]] in 1977–78, an estimated 200,000 people were infected and there were at least 594 deaths.<ref>{{cite journal | vauthors = Arzt J, White WR, Thomsen BV, Brown CC | s2cid = 31753926 | title = Agricultural diseases on the move early in the third millennium | journal = Veterinary Pathology | volume = 47 | issue = 1 | pages = 15–27 | date = January 2010 | pmid = 20080480 | doi = 10.1177/0300985809354350 }}</ref><ref>{{cite journal | vauthors = Bird BH, Ksiazek TG, Nichol ST, Maclachlan NJ | s2cid = 16239209 | title = Rift Valley fever virus | journal = Journal of the American Veterinary Medical Association | volume = 234 | issue = 7 | pages = 883–93 | date = April 2009 | pmid = 19335238 | doi = 10.2460/javma.234.7.883 }}</ref> In [[Kenya]] in 1998, the virus killed more than 400 people.{{citation needed|date=February 2021}} Since then, there have been outbreaks in [[Saudi Arabia]] and [[Yemen]] (2000),{{citation needed|date=February 2021}} [[2006–07 East Africa Rift Valley fever outbreak|East Africa (2006–2007)]],<ref>{{cite news|date=7 January 2007|title=At least 75 people die of Rift Valley Fever in Kenya|newspaper=International Herald Tribune|url=http://www.iht.com/articles/ap/2007/01/07/africa/AF-GEN-Kenya-Rift-Valley-Fever.php|url-status=live|archive-url=https://web.archive.org/web/20070109034000/http://www.iht.com/articles/ap/2007/01/07/africa/AF-GEN-Kenya-Rift-Valley-Fever.php|archive-date=9 January 2007}}</ref> Sudan (2007),<ref>{{cite news | title = Deadly fever spreads Kenya Panic | publisher = BBC | date = 26 January 2007 | url = http://news.bbc.co.uk/2/hi/africa/6301417.stm | url-status = live | archive-url = https://web.archive.org/web/20080501110543/http://news.bbc.co.uk/2/hi/africa/6301417.stm | archive-date = 1 May 2008 }}</ref> South Africa (2010),<ref>[http://www.promedmail.org/pls/apex/f?p=2400:1001:4602376937374923::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,82136 ProMED-mail] {{webarchive|url=https://web.archive.org/web/20110728121552/http://www.promedmail.org/pls/apex/f?p=2400%3A1001%3A4602376937374923%3A%3ANO%3A%3AF2400_P1001_BACK_PAGE%2CF2400_P1001_PUB_MAIL_ID%3A1000%2C82136 |date=2011-07-28 }}. ProMED-mail. Retrieved on 2014-05-12.</ref><ref>{{cite web | url =https://www.who.int/csr/don/2010_03_30a/en/index.html | title = Rift Valley fever in South Africa | publisher = WHO | url-status = dead | archive-url = https://web.archive.org/web/20100412030314/http://www.who.int/csr/don/2010_03_30a/en/index.html | archive-date = 2010-04-12 }}</ref> Uganda (2016),<ref>{{cite web | url=https://www.cdc.gov/vhf/rvf/outbreaks/summaries.html | title=Outbreak Summaries &#124; Rift Valley Fever &#124; CDC| date=2019-02-15}}</ref> Kenya (2018),<ref name="WHO_18_June_2018">{{cite web |url=https://www.who.int/csr/don/18-june-2018-rift-valley-fever-kenya/en/ |archive-url=https://web.archive.org/web/20180623005121/http://www.who.int/csr/don/18-june-2018-rift-valley-fever-kenya/en/ |url-status=dead |archive-date=June 23, 2018 |title=Rift Valley fever – Kenya |publisher=WHO |date=18 June 2018 |access-date=1 July 2018}}</ref> [[Mayotte]] (2018–2019),<ref>{{cite web |url=https://www.who.int/csr/don/13-may-2019-rift-valley-fever-mayotte-france/en/ |archive-url=https://web.archive.org/web/20190701132213/https://www.who.int/csr/don/13-may-2019-rift-valley-fever-mayotte-france/en/ |url-status=dead |archive-date=July 1, 2019 |title=Rift Valley Fever – Mayotte (France) |publisher=WHO |date=13 May 2019 |access-date=15 May 2019 }}</ref> Kenya (2020–2021)<ref>{{cite web |url=https://www.who.int/csr/don/12-february-2021-rift-valley-fever-kenya/en/ |archive-url=https://web.archive.org/web/20210212170727/https://www.who.int/csr/don/12-february-2021-rift-valley-fever-kenya/en/ |url-status=dead |archive-date=February 12, 2021 |title=Rift Valley fever – Kenya |publisher=World Health Organization |date=12 February 2021 |access-date=24 February 2021}}</ref>  and Burundi (2022).

==Biological weapon==
Rift Valley fever was one of more than a dozen agents that the [[United States]] researched as potential [[biological weapon]]s before the nation suspended its biological weapons program in 1969.<ref name=jmcenter>"[http://webarchive.loc.gov/all/20011002153149/http://www.cns.miis.edu/research/cbw/possess.htm Chemical and Biological Weapons: Possession and Programs Past and Present]", ''James Martin Center for Nonproliferation Studies'', [[Middlebury College]], April 9, 2002, accessed November 14, 2008.</ref><ref>{{cite web | url = http://www.selectagents.gov/resources/List%20of%20Select%20Agents%20and%20Toxins%2009-19-2011.pdf | publisher = USDA-APHIS and CDC: National Select Agent Registry | title = Select Agents and Toxins | date = 2011-09-19 | url-status = dead | archive-url = https://web.archive.org/web/20120225122715/http://www.selectagents.gov/resources/List%20of%20Select%20Agents%20and%20Toxins%2009-19-2011.pdf | archive-date = 2012-02-25 }}</ref>

==Research==
The disease is one of several identified by [[World Health Organization|WHO]] as a likely cause of a future epidemic in a new plan developed after the [[West African Ebola virus epidemic|Ebola epidemic]] for urgent research and development toward new diagnostic tests, vaccines and medicines.<ref>{{cite web|last1=Kieny|first1=Marie-Paule |title=After Ebola, a Blueprint Emerges to Jump-Start R&D|url=https://blogs.scientificamerican.com/guest-blog/after-ebola-a-blueprint-emerges-to-jump-start-r-d/|website=Scientific American Blog Network|access-date=13 December 2016|url-status=live|archive-url=https://web.archive.org/web/20161220134725/https://blogs.scientificamerican.com/guest-blog/after-ebola-a-blueprint-emerges-to-jump-start-r-d/|archive-date=20 December 2016}}</ref><ref>{{cite web|title=List of Pathogens|url=https://www.who.int/csr/research-and-development/list_of_pathogens/en/|website=World Health Organization|access-date=13 December 2016|url-status=dead|archive-url=https://web.archive.org/web/20161220180509/http://www.who.int/csr/research-and-development/list_of_pathogens/en/|archive-date=20 December 2016}}</ref>

==See also==
{{Portal|Viruses}}
* [[Coalition for Epidemic Preparedness Innovations]]

== References ==
{{Reflist}}

== External links ==
* [https://www.cdc.gov/vhf/rvf/ CDC RVF Information Page]
* [https://www.oie.int/fileadmin/Home/eng/Animal_Health_in_the_World/docs/pdf/Disease_cards/RIFT_VALLEY_FEVER.pdf Rift Valley Fever disease card at OIE]
* {{cite web |title=Rift Valley fever |work=Fact sheet N°207 |url=https://www.who.int/en/news-room/fact-sheets/detail/rift-valley-fever |publisher=World Health Organization |access-date=21 March 2014 |date=May 2010}}
* {{cite web |title=''Rift Valley fever virus'' |work=NCBI Taxonomy Browser |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=11588 |id=11588}}
{{Medical resources
| DiseasesDB      = 31094
| ICD11           = {{ICD11|1D44}}
| ICD10           = {{ICD10|A92.4}}
| ICD9            = {{ICD9|066.3}}
| ICDO            =
| OMIM            =
| MedlinePlus     =
| eMedicineSubj   =
| eMedicineTopic  =
| MeshID          = D012295
| Orphanet        = 319251
}}
{{Zoonotic viral diseases}}
{{Taxonbar|from=Q24809101|from2=Q14276794}}

{{DEFAULTSORT:Rift Valley Fever}}
[[Category:Arthropod-borne viral fevers and viral haemorrhagic fevers]]
[[Category:Tropical diseases]]
[[Category:Zoonoses]]
[[Category:Insect-borne diseases]]
[[Category:Sheep and goat diseases]]
[[Category:Biological agents]]
[[Category:Virus-related cutaneous conditions]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Wikipedia infectious disease articles ready to translate]]
[[Category:Biological anti-agriculture weapons]]