Rift Valley fever

RVF is a notifiable medical condition and should be notified to your local Department of Health. Individual cases should be confirmed by laboratory testing. If exposure is suspected through contact with infected animals, zoological cases in livestock should be reported immediately to local and/or national authorities.

Urgent considerations

Rift Valley fever virus (RVFV) has the potential to have serious agricultural and public health impacts. RVF is listed as a notifiable disease by the World Organization for Animal Health, and is classified as a select agent regulated by the United States Department of Agriculture and the United States Department of Health and Human Services.[9]Golnar AJ, Turell MJ, LaBeaud AD, et al. Predicting the mosquito species and vertebrate species involved in the theoretical transmission of Rift Valley fever virus in the United States. PLoS Negl Trop Dis. 2014 Sep 11;8(9):e3163. http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0003163 http://www.ncbi.nlm.nih.gov/pubmed/25211133?tool=bestpractice.com [59]Hartley DM, Rinderknecht JL, Nipp TL, et al; National Center for Foreign Animal and Zoonotic Disease Defense Advisory Group on Rift Valley Fever. Potential effects of Rift Valley fever in the United States. Emerg Infect Dis. 2011 Aug;17(8):e1. http://wwwnc.cdc.gov/eid/article/17/8/10-1088_article http://www.ncbi.nlm.nih.gov/pubmed/21801607?tool=bestpractice.com [60]United States Department of Agriculture. Foreign Animal Disease Preparedness and Response Plan (FAD PReP). Disease response strategy: Rift Valley fever. Aug 2013 [internet publication]. https://www.aphis.usda.gov/animal_health/emergency_management/downloads/ppr_rvf_disease_strategy.pdf Many local and foreign animal disease preparedness and response plans are available.

Supportive therapies for symptomatic patients

Access to compassionate care may increase healthcare seeking behaviour and lead to documentation of more mild human cases resulting in monitored outbreak spread and better resource allocation. Treatment is generally supportive as there is no specific antiviral treatment available.

A large percentage of RVF cases are mild and self-limited. Treatment is similar to most other influenza-like illnesses: rest, maintain generous fluid intake, and symptomatic treatment with non-prescription medications. Patients should seek medical attention if the influenza-like symptoms can no longer be adequately managed by non-prescription medications (e.g., severe dehydration) or last longer than 1 week.

Patients should seek immediate medical care if they have any neurological changes such as severe headaches, photophobia, seizures, or change in mental state; any visual disturbance (blurred or decreased vision); or any signs of haemorrhage (including jaundice).

Early dialysis for patients with renal failure may improve outcome.[1]National Institute for Communicable Diseases. Healthcare workers guidelines on Rift Valley fever (RVF). Jan 2021 [internet publication]. https://www.nicd.ac.za/wp-content/uploads/2021/02/Rift-Valley-Fever-2021-Guidelines-for-Health-Care-Workers_110321.pdf [2]Jankovic J, Mazziotta J, Pomeroy S, et al. Bradley and Daroff's neurology in clinical practice, 2-volume set. 8th ed. Elsevier. 2021.

Some therapies are not recommended for the treatment of RVF, such as ribavirin or moderate to high dosages of corticosteroids. Ribavirin is specifically contraindicated due to increasing incidence of central nervous system disease.

Visual disturbance/loss of vision

Treatment is generally supportive, as there is no specific ocular treatment available. Patients should be followed by an ophthalmologist. Patients experiencing loss of vision or blurred vision should be monitored for potential progression to retinitis, complete blindness, or permanent vision loss. Eyes should be examined for the development of lesions, including retinal haemorrhage, vitreous reactions, optic disc oedema, anterior uveitis, and retinal vasculitis.[51]Al-Hazmi A, Al-Rajhi AA, Abboud EB, et al. Ocular complications of Rift Valley fever outbreak in Saudi Arabia. Ophthalmology. 2005 Feb;112(2):313-8. http://www.ncbi.nlm.nih.gov/pubmed/15691569?tool=bestpractice.com

Encephalitis

Admit the patient to hospital to rule out other treatable illnesses (such as herpes simplex virus encephalitis) and to provide intensive supportive care.

Basic resuscitation measures for people with reduced level of consciousness includes ensuring airway patency, breathing and circulation, intravenous fluids, and prevention and management of secondary bacterial infections, seizures (if they occur), and venous thromboembolism.

There are no specific drug therapies for complications of encephalitis caused by RVFV and there is no evidence that antivirals are effective.

Haemorrhage or DIC

Major bleeding occurs infrequently, but is a manifestation of severe infection and is fatal in 50% of patients.[11]World Health Organization. Rift Valley fever. Feb 2018 [internet publication]. http://www.who.int/mediacentre/factsheets/fs207/en When available, give platelet, plasma, and red blood cell transfusions according to local protocols.