Ep 164 Rift Valley Fever: Ruminating on ruminants

Overview

Rift Valley Fever (RVF) is a mosquito-borne disease caused by the Rift Valley Fever virus, an RNA virus in the genus Phlebovirus. This virus belongs to the order Bunyavirales, which includes other notable viruses like hantaviruses and Lassa fever virus 1. Erin Updyke and Erin Welsh discuss the surprising lack of awareness about RVF despite its significant impact, highlighting its classification as a classic TPWKY topic 2. The first recorded human death from RVF was documented in 1934, illustrating the virus's historical presence and deadly potential 3.

   

Symptoms

Symptoms of Rift Valley Fever can range from mild to severe, with fever, headache, and muscle pain being common initial signs. Severe cases can lead to hemorrhagic fever, liver damage, and even death, with about 50% mortality in those developing hemorrhagic symptoms 4. Erin Updyke explains that the virus can also cause spontaneous abortions in livestock, with mortality rates in young animals reaching up to 100% 5. The variability in symptoms and severity is influenced by factors like host immune response and transmission route 6.

   

Transmission

Rift Valley Fever is primarily transmitted through mosquito bites, with vertical transmission from mosquitoes to their eggs playing a significant role in the virus's persistence 7. Erin Welsh notes that humans often contract the virus through direct contact with infected animals, particularly in agricultural settings 8. While aerosol transmission is possible, it is less common, and human-to-human transmission has not been documented, making direct animal contact the primary risk factor for human infection 9.