Rift valley fever: Difference between revisions

Revision as of 02:42, 10 June 2015

Viral illness caused by RVF virus, a bunyaviridae
Primarily infects domesticated animals; cattle, sheep, buffalo, etc.
Outbreaks related to unusually heavy rainfall and flooding
Found mostly in eastern and southern Africa where domesticated animals are raised
- Can be found in most of Africa
- Recent outbreaks in Saudi Arabia and Yemen (first outside African continent)
Outbreaks cause major economic impact with livestock death

Mosquitos, most commonly Aedes, are a reservoir and vector for RVF virus
- Able to live with the virus and pass on to offspring, virus remains viable in eggs
- Bite livestock and humans to cause infection
- Increased rainfall increases mosquito numbers and is associated with outbreaks
Humans are most commonly infected through direct contact of blood or other bodily fluids of infected livestock
- Slaughter, veterinary procedures, obstetrical procedures
No documented human to human transmission
Aerosolized transfer has occurred in laboratory settings

No symptoms or flu-like illness (fever, myalgias, joint pain, headache)
Early disease can be mistaken for meningitis with occasional neck stiffness and sensitivity to light
Resolves within 1 week

Occular form- 0.5-2% of patients
- Mild disease form + retinal lesions, blurred and decreased vision
- Retinal lesions occur 1-3 weeks after disease onset and last 10-12 weeks
- 50% of patients with macular lesions will develop permanent vision loss
Meningoencephalitis form- <1% of patients
- Severe headache, memory loss, hallucinations, confusion, vertigo, seizures, coma, and late neurological complications
- Onset is 1-4 weeks after mild symptoms
- Residual severe neurological deficits are common
Hemorrhagic fever form- <1% of patients
- Jaundice is first sign due to liver dysfunction
- Hemorrhage (vomit, stool, gums, menorrhagia), purpuric rash, echymosis
- Onset is 2-4 days after illness, death in 3-6 days
- Most fatalities from RVF, 50% fatality rate

Pursue other possible causes of fever
IgM ELISA, viral detection, and RT-PCR can be used to diagnose acute infection. IgG ELISA for previous infection.

Inactivated vaccine has been developed for humans
- Not licensed and not commercially available
- Experimental use on veterinary and lab workers
Approved vaccines for livestock

Isolation precautions: standard, contact, and consider droplet
Admit if severe form suspected, likely ICU
- Consult ID
- Consult ophthalmology for ocular form

Authors:

@@ Line 48: / Line 48: @@
 ==Management==
-*Mild disease syndromes require no intervention and are self limited
+*Mild: requires no intervention (self limited_
-*No specific treatment exists for severe disease forms
+*Severe
 **Supportive Care
 ***Pain control
-****DO NOT use ASA in hemorrhagic form
+****DO NOT use [[ASA]] in hemorrhagic form
 **[[IVFs]]
 **Blood Component [[Transfusion]] - consider in hemorrhagic shock
+===Vaccines===
 *Inactivated vaccine has been developed for humans
 **Not licensed and not commercially available