ContentsSynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferencesView all Images (2)
Rift Valley fever
Print
Other Resources UpToDate PubMed

Rift Valley fever

Print Images (2)
Contributors: Justin S. Gatewood MD, Edith Lederman MD, Noah Craft MD, PhD
Other Resources UpToDate PubMed

Synopsis

Rift valley fever (RVF) is a zoonotic disease of the Phlebovirus genus in the Bunyaviridae family, endemic to areas of eastern and southern Africa, the Middle East, and Madagascar. The disease is naturally spread to humans by mosquitoes, contact with or inhalation of aerosolized body fluids of infected animals (eg, cattle, sheep, goats, buffalo, camels), or by drinking raw milk from infected animals.
 
Aedes mosquitoes are born infected, as the virus transmits from the mother to the eggs. Animals are infected by mosquito bites, and then other types of mosquitoes and biting insects (eg, midges) subsequently become infected by feeding on these animals. Disease rates are higher during the rainy season or flooding, as the eggs are reconstituted from their desiccated state.
 
Although the mortality rate of typical RVF is less than 1%, the mortality rate, if it progresses to a hemorrhagic fever, is approximately 50%. In addition, the economic repercussions of an outbreak can be severe due to the loss of infected farm animals.

RVF has an incubation period of 2-6 days. Many patients may be asymptomatic or have mild, nonspecific symptoms that do not prompt medical evaluation. Those with symptoms present with the sudden onset of fever, headache, generalized weakness, myalgia, backache, photophobia, and vomiting. Less frequently, the disease progresses into eye disease (see below), meningoencephalitis, or hemorrhagic fever.
 
Eye disease, which includes lesions in the macula and permanent vision loss, vasculitis, hepatitis, or meningoencephalitis, occurs in about 10% of all patients within 1-3 weeks. Hemorrhagic fever develops within an average of 3 days and manifests with liver disease, jaundice, hematemesis, hematochezia, purpura, and gingival bleeding.
 
Person-to-person transmission is not known to occur. A vaccine has been developed for veterinary use as well as human use, but the human vaccine is not commercially available.

RVF is uncommon in young children and infants because the virus is most effectively spread via direct contact with infected animals and/or animal products.

Codes

ICD10CM:
A92.4 – Rift Valley fever

SNOMEDCT:
402917003 – Rift valley fever

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

Best Tests

Subscription Required

Management Pearls

Subscription Required

Therapy

Subscription Required

References

Subscription Required

Last Updated: 10/03/2017
Copyright © 2019 VisualDx®. All rights reserved.
Rift Valley fever
Print 2 Images
View all Images (2)
(with subscription)
Rift Valley fever : Fever, Headache, Vomiting, Photophobia, Vision loss, Myalgia
Copyright © 2019 VisualDx®. All rights reserved.