Rift Valley fever: An emerging zoonotic threat to global health and agriculture

Abstract

Rift Valley fever (RVF) is an acute, mosquito-borne zoonotic disease caused by the RVF virus (RVFV), which belongs to the Phlebovirus genus of the Bunyaviridae family. The infection mainly targets domestic ruminants such as sheep, goats, cattle, and camels, with sheep showing the highest vulnerability. The virus is spread predominantly through the bites of Aedes and Culex mosquitoes, although humans may also become infected by direct exposure to blood, organs, or secretions of diseased animals. In livestock, the illness is marked by sudden fever, ocular and nasal discharges, vomiting, and swollen lymph nodes. Severe cases often lead to abortion waves in pregnant animals and high mortality in newborns, especially among lambs and kids. In humans, RVF may present with flu-like symptoms, but in rare instances, it can progress to severe complications such as encephalitis, retinitis, or hemorrhagic fever. Due to its potential for rapid spread, zoonotic transmission, and misuse as a bioterrorism agent, RVFV is listed as a select agent. Diagnostic approaches include serological tests for RVFV-specific immunoglobulin M and immunoglobulin G antibodies, molecular detection of viral RNA, and virus isolation in specialized laboratories. Vaccination remains the most effective strategy for controlling RVF in animals, with both inactivated and live-attenuated vaccines in use. The endemic nature of RVF in sub-Saharan Africa and the Arabian Peninsula, along with environmental changes and global livestock movement, has raised concerns about the virus’s transboundary spread. The European Food Safety Authority highlights the movement of infected animals and vector expansion as key risk factors for RVF introduction into Europe, emphasizing the need for vigilant surveillance and preventive measures.

Keywords: Rift Valley fever virus; Vector-borne disease; Aedes; Culex; Phlebovirus; Bunya virus

Core Tip: Rift Valley fever is a re-emerging zoonotic disease with significant health and economic impacts across Africa and the Middle East. This mini-review comprehensively discusses its virology, transmission, clinical manifestations, and challenges in diagnosis, treatment, and vaccine development. It highlights current outbreak trends, environmental and socioeconomic factors, and emphasizes the urgent need for global surveillance, intersectoral collaboration, and the development of effective prevention and control strategies for Rift Valley fever.