Most infected individuals remain asymptomatic or develop a mild form of the disease, consisting of fever, muscle and joint pain, weakness, backache, and headache. The clinical picture may resemble meningitis with neck stiffness photophobia, anorexia, and vomiting. Still, symptoms may be difficult to recognize, especially if the epizootic context is unknown and diagnosis may depend on reliable laboratory techniques.

Severe illness consists of ocular disease, meningoencephalitis, and hemorrhagic fever. Ocular symptoms like blurred or decreased vision signify retinal or macular damage, that might spontaneously resolve or become permanent, leading to vision loss. Central nervous system disease manifests as an intense headache, hallucinations, confusion, seizures, lethargy, and coma, with persistence of neurologic deficit, whereas hemorrhagic fever signifies liver damage and manifests as jaundice, melena, hematemesis, menorrhagia, epistaxis or other mucosal hemorrhages, purpuric rash or ecchymosis. 50% of patients with hemorrhagic fever die within one week of symptom onset. Jaundice, neurologic and hemorrhagic forms have a higher incidence of mortality [1] [2]. Central nervous system disease may be followed by permanent neurologic deficits.

Although abortion is the most prominent trait of this disease in animals, pregnant women, newborns, and small children usually are spared from this infection. The reason for this might be that they usually are not exposed to diseased animals and more efforts are made to prevent their exposure to mosquitoes; if other reasons exist, they are yet to be reported.

Rift valley fever (RVF) induces life-long immunity.

Ocular disease becomes apparent 7-21 days after infection and resolves after 10-12 weeks. Encephalitis may be suspected 1-4 weeks after initial general symptoms of the disease appear, while hemorrhages occurring much sooner i.e. 2-4 days following exposure, entail a poor prognosis.

• Generalized Lymphadenopathy

  There is a generalized lymphadenopathy involving the superficial and visceral lymph nodes. These are oedematous with petechial haemorrhages. The spleen may or may not be enlarged with subcapsular haemorrhages. [fao.org]

• Fever

  24 November 2016 Rift Valley Fever in Niger 29 September 2016 Rift Valley fever in Niger 2 August 2016 Rift Valley fever in China 1 November 2012 Rift Valley fever in Mauritania 12 May 2010 Rift Valley fever in South Africa- update 2 4 May 2010 Rift [who.int]

  Bath, Rift Valley Fever, Diseases of Sheep, (469-473), (2008). [doi.org]

  No data are available on the animal morbidity and mortality due to Rift Valley fever. [cdc.gov]

  fever virus infection had miscarriages compared with 12 (12%) of 102 women negative for Rift Valley fever virus (p INTERPRETATION: This study is the first to show an association between infection with Rift Valley fever virus and miscarriage in pregnant [ncbi.nlm.nih.gov]

• Anorexia

  Nonspecific signs of fever, anorexia, weakness, lymphadenopathy, respiratory signs and hemorrhagic diarrhoea can be seen in young animals. [galvmed.org]

  The clinical picture may resemble meningitis with neck stiffness photophobia, anorexia, and vomiting. [symptoma.com]

  Clinical Signs Fever Anorexia (poor appetite) Weakness Death in young animals Abortion (may be 100% in the herd) Treatment There is no specific treatment for Rift Valley Fever. [thecattlesite.com]

  In young animals, peracute disease causes anorexia, listlessness, collapse and death. Humans develop malarial-like disease. High risk individuals include farmers, veterinarians and abattoir staff. [web.archive.org]

  The outstanding symptoms were headache, backache, anorexia, prostration and fever. The duration of fever ranged from 2 to 6 days. All the patients recovered without exhibiting any permanent sequelae, but the rapidity of convalescence was variable. [jimmunol.org]

• Weight Loss

  Humans experience flu-like symptoms, which may include fever, weakness, weight loss, dizziness, headache, nausea, vomiting, and muscle and joint pain. About 1% of those infected experience more severe symptoms. [floridahealth.gov]

  Patients who become ill usually experience fever, generalized weakness, back pain, dizziness, and extreme weight loss at the onset of the illness. Typically, patients recover within two days to one week after onset of illness. Q. [mosquitocontrol.org]

  The symptoms of uncomplicated infections may include fever, headache, generalized weakness, dizziness, weight loss, myalgia and back pain. Some patients also have stiffness of the neck, photophobia and vomiting. [healio.com]

  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. [en.wikipedia.org]

  A loss of body weight exceeding 15% of the initial body weight is indicated by an asterisk. (D) Clinical signs of diseases in mice challenged with RST-MP12-S, RST-MP12-M, or RST-MP12-L. [doi.org]

• High Fever

  Clinical signs of RVF · Sudden onset of abortion storms · Up to 100 percent mortality in lambs under five to six days old · High fever, lymphadenitis, nasal and ocular discharges in mature animals · Profuse fetid diarrhoea (often haemorrhagic) · Vomiting [fao.org]

  It is a member of the Phlebovirus genus and causes a high fever and severe disease in infected animals. The virus has an incubation period (the time it takes from infection to first signs and symptoms) of two to six days. [thesun.co.uk]

  The disease is characterized by sudden onset of high fever, severe headache, myalgia, arthralgia, and photophobia in humans [1]. [microbewiki.kenyon.edu]

  Among the 11 confirmed cases, 45.5% (5 of 11) were symptomatic with high fever 100% (5 of 5), jaundice 60% (3 of 5), encephalitis 40% (2 of 5), and macular retinitis with optic disc edema 20% (1 of 5). [ofid.oxfordjournals.org]

  The viral disease was identified for the first time in 1930 in Kenya and is characterized by high fever and abortion in livestock and high neonatal mortality mainly in sheep [ 3 – 6 ]. [bmcvetres.biomedcentral.com]

• Fatigue

  On March 9, 2016, a male butcher from Kabale District, Uganda, aged 45 years, reported to the Kabale Regional Referral Hospital with fever, fatigue, and headache associated with black tarry stools and bleeding from the nose. [ncbi.nlm.nih.gov]

  […] v=9joq-Ghqghc. 2016 – Uganda On March 2016, a male butcher from Kabale District in western Uganda reported to a local hospital with symptoms of headache, fever, fatigue and bleeding, subsequently testing positive for Rift Valley Fever. [cdc.gov]

  On March 2016, a male butcher from Kabale District in western Uganda reported to a local hospital with symptoms of headache, fever, fatigue and bleeding, subsequently testing positive for Rift Valley Fever. [en.wikipedia.org]

• Vomiting

  Affected animals show: Fever (40-42°C) Anorexia, depression and weakness in adult cattle and lambs, Mucopurulent nasal discharge in sheep and goats, Vomiting, Diarrhea in cattle, Vomiting and jaundice in sheep, Sometimes haemorrhagic diarrhoea in lambs [lrd.spc.int]

  Anorexia, injected conjunctivae, nasal discharges, vomiting and other signs are seen but are generally less severe than in young animals. Abortion is a feature, as is diarrhoea. [fao.org]

  The clinical picture may resemble meningitis with neck stiffness photophobia, anorexia, and vomiting. [symptoma.com]

  With no specific treatment or effective human vaccine, Rift Valley fever can cause blindness and severe hemorrhaging, leading the victim to vomit blood or even bleed to death. [voanews.com]

  However, those patients who develop hemorrhagic fever often have vomiting and diarrhea with blood and may bleed from the gums. These patients also may develop liver complications. [thecattlesite.com]

• Abdominal Pain

  Affected animals are listless and reluctant to move or feed and may show signs of abdominal pain. Mortality in young lambs is high (90%–100%), and animals usually die within 2–3 days. [msdvetmanual.com]

  pain, photosensitivity, anorexia, excessive salivation and decreased milk production. [en.wikivet.net]

• Loss of Appetite

  Sensitivity to light, neck stiffness, vomiting and loss of appetite are also common. [iamat.org]

  Some develop neck stiffness, sensitivity to light, loss of appetite and vomiting, in the early diagnosing process these symptoms can often be confused with meningitis. [thesun.co.uk]

  Some patients develop neck stiffness, sensitivity to light, loss of appetite and vomiting; in these patients the disease, in its early stages, may be mistaken for meningitis. [web.archive.org]

• Nausea

  Humans experience flu-like symptoms, which may include fever, weakness, weight loss, dizziness, headache, nausea, vomiting, and muscle and joint pain. About 1% of those infected experience more severe symptoms. [floridahealth.gov]

• Tachycardia

  Tachycardia, cyanosis, petechiation, haemorrhage and clotting defects are haematological consequences of RVF. The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea. [web.archive.org]

• Cyanosis

  Tachycardia, cyanosis, petechiation, haemorrhage and clotting defects are haematological consequences of RVF. The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea. [web.archive.org]

• Jaundice

  The necrotic changes induce jaundice and a stage is reached when the liver has a bronze appearance as the congestion, necrotic areas and icterus develop. At later stages the liver will be completely yellow with jaundice. [fao.org]

  Jaundice, neurologic and hemorrhagic forms have a higher incidence of mortality. Central nervous system disease may be followed by permanent neurologic deficits. [symptoma.com]

  Our data reveal an identifiable clinical syndrome suggestive of severe RVF, characterized by fever, large-joint arthralgia, and gastrointestinal complaints and later followed by jaundice, right upper-quadrant pain, and delirium, often coinciding with [ncbi.nlm.nih.gov]

  Affected animals show: Fever (40-42°C) Anorexia, depression and weakness in adult cattle and lambs, Mucopurulent nasal discharge in sheep and goats, Vomiting, Diarrhea in cattle, Vomiting and jaundice in sheep, Sometimes haemorrhagic diarrhoea in lambs [lrd.spc.int]

  In older animals, the liver is enlarged and inflamed, with many foci of necrosis which are bronzed and jaundiced. The gall bladder may also be distended and haemorrhagic. [web.archive.org]

• Blurred Vision

  These lesions are usually associated with blurred vision and/or mild to severe vision loss, which may or may not resolve during convalescence. [infectionlandscapes.org]

• Myalgia

  The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease. [web.archive.org]

  The disease is characterized by sudden onset of high fever, severe headache, myalgia, arthralgia, and photophobia in humans [1]. [microbewiki.kenyon.edu]

  The symptoms of uncomplicated infections may include fever, headache, generalized weakness, dizziness, weight loss, myalgia and back pain. Some patients also have stiffness of the neck, photophobia and vomiting. [healio.com]

  The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease. [4] Diagnosis Following infection viraemia is often high (though short lived) so the virus can be easily detected in the blood shortly after. [en.wikivet.net]

• Arthralgia

  Our data reveal an identifiable clinical syndrome suggestive of severe RVF, characterized by fever, large-joint arthralgia, and gastrointestinal complaints and later followed by jaundice, right upper-quadrant pain, and delirium, often coinciding with [ncbi.nlm.nih.gov]

  The disease is characterized by sudden onset of high fever, severe headache, myalgia, arthralgia, and photophobia in humans [1]. [microbewiki.kenyon.edu]

  The mild disease course typically presents as an influenza-like illness with abrupt onset of fever, mylagia and arthralgia, and headache. [infectionlandscapes.org]

  Systemic reaction parameters include fever, chills, headache, malaise, myalgia, arthralgia, sore throat, gastric upset, dizziness, photophobia and skin rash. [google.ch]

• Petechiae

  On necropsy, in the viraemic stage, widespread petechiae and ecchymoses on serous surfaces and organs will be seen and extravasated blood present in the body cavities. [web.archive.org]

  The symptoms may include jaundice, hematemesis, melena, a purpuric rash, petechiae and bleeding from the gums. Hemorrhagic fever frequently progresses to frank hemorrhages, shock and death (case fatality rate of up to 50%). [healio.com]

  In all animals, the spleen and peripheral lymph nodes are enlarged and edematous and may show petechiae. [msdvetmanual.com]

  On post mortem during the viraemic stage, widespread petechiae and ecchymoses on serous surfaces and organs will be seen and present in the body cavities. [en.wikivet.net]

• Skin Rash

  She delivered baby of 3.2 kg with skin rash, palpable liver and spleen. The two samples from the mother and neonate were found to be positive for RVF-IgM. This report demonstrate that, RVF can be vertically transmitted. [ncbi.nlm.nih.gov]

  During the 2007 outbreak in Sudan, a 29-year-old pregnant woman presented in early labor with symptoms suggestive of RVF and delivered a baby weighing 3.2 kg with skin rash, palpable liver, and spleen. [frontiersin.org]

  Systemic reaction parameters include fever, chills, headache, malaise, myalgia, arthralgia, sore throat, gastric upset, dizziness, photophobia and skin rash. [google.ch]

• Epistaxis

  […] disease manifests as an intense headache, hallucinations, confusion, seizures, lethargy, and coma, with persistence of neurologic deficit, whereas hemorrhagic fever signifies liver damage and manifests as jaundice, melena, hematemesis, menorrhagia, epistaxis [symptoma.com]

  The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea. Fever, lymphadenopathy, depression and lethargy usually accompany infection. Hepatitis may cause consequent photosensitisation. [web.archive.org]

• Headache

  Most infected individuals remain asymptomatic or develop a mild form of the disease, consisting of fever, muscle and joint pain, weakness, backache, and headache. [symptoma.com]

  The mild symptoms may include: fever, muscle pains, and headaches which often last for up to a week. [en.wikipedia.org]

  The virus also infects humans, commonly causing malaise, fever and headaches; in epidemics in North Africa, encephalitis and death have also occurred. [epi.ufl.edu]

  Mild symptoms include hemorrhagic fever, muscle pains and headaches whereas severe symptoms range from loss of sight within weeks of infection to brain inflammation, which can lead to headaches and seizures. ... [allafrica.com]

  On March 9, 2016, a male butcher from Kabale District, Uganda, aged 45 years, reported to the Kabale Regional Referral Hospital with fever, fatigue, and headache associated with black tarry stools and bleeding from the nose. [ncbi.nlm.nih.gov]

• Confusion

  Central nervous system disease manifests as an intense headache, hallucinations, confusion, seizures, lethargy, and coma, with persistence of neurologic deficit, whereas hemorrhagic fever signifies liver damage and manifests as jaundice, melena, hematemesis [symptoma.com]

  Symptoms include respiratory issues and mental confusion. Rift Valley fever was first identified in 1931 in sheep farmers in Kenya and has since been found in outbreaks mostly throughout Africa. [mnn.com]

  Some develop neck stiffness, sensitivity to light, loss of appetite and vomiting, in the early diagnosing process these symptoms can often be confused with meningitis. [thesun.co.uk]

  Confusion, loss of memory, convulsions, hallucination and headache are common features of this syndrome. Coma can also ensue. Mortality associated with this syndrome is also low, but chronic neurologic deficit often persists and can be quite severe. [infectionlandscapes.org]

  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. [en.wikipedia.org]

Laboratory techniques used in order to establish the diagnosis include reverse transcriptase-polymerase chain reaction (RT-PCR) [3] [4], virus isolation in cell cultures [5], enzyme-linked immunoassay (ELISA) to detect viral antigens [6] [7], immunoglobulin IgM and IgG [8] and real-time reverse transcription-loop-mediated isothermal amplification assays (RT-LAMP) [9] [10], a new, highly specific and sensitive diagnostic test. Samples should be handled with caution and processed in specialized facilities, as they might be a bio- hazard. The virus is isolated from serum, liver, spleen or brain tissue. Rapid virus identification in severe cases is extremely important as patients need special management.

Immunological viral antigen detection methods include agar gel immunodiffusion and immunostaining on impression smears or on cryostat sections of liver, spleen, and brain, while histopathological examination reveals specific characteristics [11] [12]. Sandwich ELISA for antigen detection (sAg-ELISA) is a new technique to identify the disease and it is less dangerous to laboratory personnel [13] [14].

Antibody detection methods include hemagglutination-inhibition, complement fixation, indirect immunofluorescence which aim to prove seroconversion and virus neutralization test which is considered to be the gold standard [11] [8].

This resolves without treatment over a week. Treatment Most cases resolve without treatment. Severe illness needs hospital intensive care support. There is no specific treatment against the virus. [fitfortravel.nhs.uk]

Treatment Treatment typically includes supportive care and the use of experimental antiviral drugs. At this time the United States does not have a licensed human or animal vaccine. [floridahealth.gov]

Treatment No treatment is available. Control Modified live and inactivated vaccines are available. Live vaccination is only recommended in non-pregnant animals due to its ability to cause abortion and neurological deficits in lambs. [web.archive.org]

The patient developed multiorgan dysfunction and gradually recovered with continuous renal replacement therapy and a short regimen of methylprednisolone treatment. [ncbi.nlm.nih.gov]

Clinical Signs Fever Anorexia (poor appetite) Weakness Death in young animals Abortion (may be 100% in the herd) Treatment There is no specific treatment for Rift Valley Fever. [thecattlesite.com]

Encephalitis may be suspected 1-4 weeks after initial general symptoms of the disease appear, while hemorrhages occurring much sooner i.e. 2-4 days following exposure, entail a poor prognosis. [symptoma.com]

D’Agati and Ibrahim Batal, Donor APOL1 high-risk genotypes are associated with increased risk and inferior prognosis of de novo collapsing glomerulopathy in renal allografts, Kidney International, 10.1016/j.kint.2018.06.024, (2018). Sanaa M. [doi.org]

Suspected VHF in which the etiology is uncertain should be initially managed with the most cautious infection control measures. [ncbi.nlm.nih.gov]

By early December 2016, accumulating disease data suggested that the outbreak of Rift Valley Fever was of modest size, and plans to explore other etiologies were formulated. References: WHO: Disease Outbreak News, 29 September 2016. [cdc.gov]

Etiology RVF is caused by RVF virus which belongs to the family Bunyaviridae and the genus Phlebovirus. [austinpublishinggroup.com]

ETIOLOGIC DIAGNOSIS: Bunyaviral hepatitis and cholecystitis CAUSE: Rift Valley fever virus (RVFV) (phlebovirus) CONDITION: Rift Valley Fever GENERAL DISCUSSION: · Zoonotic disease of Africa that results in abortion storms, neonatal mortality and hepatic [askjpc.org]

That this “top 10” list of agricultural diseases on the move includes, exclusively, conditions of viral etiology is not coincidental. [doi.org]

Author information 1 Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland. [ncbi.nlm.nih.gov]

Further screening was done by title and abstract focusing on studies reporting the epidemiology of RVF including ecology and risk factors as well as molecular diversity, spatial–temporal epidemiology, and risk modeling. [web.archive.org]

[…] overview for 2016 Publication Rift Valley fever - Annual Epidemiological Report for 2016 Publication Communicable Disease Threats Report, 10-16 June 2018, week 24 Publication Rift valley fever - Annual Epidemiological Report for 2015 Publication Rift [ecdc.europa.eu]

Serial blood samples from these men were analyzed for a series of biomarkers specific for various aspects of human pathophysiology including inflammation, endothelial function and coagulopathy. [ncbi.nlm.nih.gov]

We posit that there is a critical need for new approaches to RVF control that will prevent or at least reduce future morbidity and economic stress. [doi.org]

Overall knowledge score on RVF was found to be a significant predictor of good preventive practice of the disease (OR = 1.073, 95% CI = 1.047-1.101). [ncbi.nlm.nih.gov]

“Animal vaccination and mosquito control could even prevent major outbreaks, if initiated ahead of time. There is a window of opportunity, but once outbreaks begin, it’s too late for these preventative actions.” [climate.gov]

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