Sandfly Fever Virus (Phlebovirus): Transmission, Molecular Biology, Epidemiology, and Clinical Management

Sandfly fever viruses, classified within the Phlebovirus genus of the Phenuiviridae family, are emerging pathogens transmitted to humans through the bite of infected phlebotomine sandflies, primarily Phlebotomus papatasi. These enveloped viruses possess a tripartite, negative-sense single-stranded RNA genome. The three segments large (L), medium (M), and small (S) encode the RNA-dependent RNA polymerase, the envelope glycoproteins (Gn and Gc), and the nucleocapsid protein (N), respectively. The glycoproteins are critical for host cell entry, while the non-structural protein (NSs) encoded by the S segment is a key virulence factor, acting as an interferon antagonist to suppress the host's antiviral immune response. Human infection results in a self-limiting acute febrile illness known as sandfly fever or pappataci fever. After an incubation period of approximately six days, symptoms suddenly appear, including high fever, severe headache, photophobia, myalgia, and conjunctival injection. The illness typically r