Punta Toro phlebovirus

As a member of the order Bunyavirales, PTV possesses many of the type virus structural characteristics. PTV has a helical nucleocapsid as well as an outer envelope. On the viral envelope PTV has two major glycoproteins, Gn and Gc, that function in host-cell binding and entry. Within the genus Phlebovirus, these glycoproteins form a characteristic icosahedral lattice with a triangulation number of T=12. Due to this structure, PTV appears as a relatively spherical particle when viewed in an electron micrograph with a diameter from 80 to 120 nm.[2][3]

The genome structure of PTV is negative sense, linear segmented RNA genome. The genome consists of three individual segments or varying length: S (1.7kb), M (3.2kb), and L (6.4kb) that encode for a total of six viral proteins. In terms of gene expression, PTV operates by using a strong hairpin sequence on the terminal end of each segment, coupled with the use of ambisense for the S segment and leaky scanning for the M segment. The process of transcription takes place in the host cell cytoplasm with the use of an RNA-dependent RNA polymerase, and enters replication after enough nucleoprotein has built up to form new intact virus particles.[2][3]

PTV is a member of the phlebotomus fever subgroup of Phleboviruses, and as the name suggests, causes an acute febrile illness. Acute febrile illness in humans is characterized by a rapid onset of fever that is often accompanied by secondary symptoms such as a headache, chills, myalgias and arthralgias.[4] This illness will last for about 2–5 days and is not considered to be highly virulent in humans, however, testing in Syrian hamsters has revealed high virulence for the PTV-A serotype and a low virulence for the PTV-B serotype. Although relatively low numbers of human infection with this virus have been reported, the virus is of public health interest and further research will need to be conducted.[1]