Dobrava-Belgrade virus

Dobrava-Belgrade virus (DOBV) is the main cause of hemorrhagic fever with renal syndrome (HFRS) in southern Europe. In its natural reservoirs, DOBV causes a persistent, asymptomatic infection and is spread through excretions, fighting, and grooming. Humans can become infected by inhaling aerosols that contain rodent saliva, urine, or feces, as well as through bites and scratches. In humans, infection causes such as fever and headache, as well as the appearance of spots on the skin and renal symptoms such as kidney swelling, excess protein in urine, blood in urine, decreased urine production, and kidney failure. Acute respiratory distress syndrome occurs in about 10% of cases.

DOBV has four genotypes: Dobrava virus, Sochi virus, Kurkino virus, and Saaremaa virus. These genotypes are native to different rodent species and vary in how severe of illness they cause. Dobrava virus is carried by the yellow-necked mouse (Apodemus flavicollis) and has moderate-to-severe symptoms with a case fatality rate of 10–12%. Sochi virus is native to the Black Sea field mouse (Apodemus ponticus) and has moderate-to-severe symptoms and a case fatality rate of at least 6%. Kurkino virus is transmitted by the striped field mouse (Apodemus agrarius) and has mild-to-moderate symptoms with a 0.3–0.9%. Lastly, Saaremaa virus, also transmitted by the striped field mouse, is not associated with disease or mortality.

The genome of DOBV is about 11.8 kilobases (kb) in length and segmented into three negative-sense, single-stranded RNA (-ssRNA) strands. The small strand encodes the viral nucleoprotein, the medium strand encodes the viral spike protein, which attaches to cell receptors for entry into cells, and the long strand encodes the viral RNA-dependent RNA polymerase (RdRp), which replicates and transcribes the genome. Genome segments are encased in nucleoproteins to form ribonucleoprotein (RNP) complexes that are surrounded by a viral envelope that contains spikes emanating from its surface.

Dobrava-Belgrade virus replicates first by binding to the surface of cells with its envelope spikes. Virus particles, called virions, are then taken into the cell by endosomes, where a drop in pH causes the viral envelope to fuse with the endosome, which releases viral RNA into the host cell. RdRp then transcribes the genome for translation by host cell ribosomes and produces copies of the genome for progeny viruses. New virions are assembled at the endoplasmic reticulum and bud from its surface to obtain their viral envelope. Progeny viruses are then transported by a cellular vesicle to the cell membrane, where they leave the cell by exocytosis.

Dobrava-Belgrade virus was first discovered in 1992 after being isolated from the lung tissue of a yellow-necked mouse in Dobrava, Slovenia. At the same time, an identical virus was identified in Belgrade, Serbia, earning the virus the name "Dobrava-Belgrade virus". Within a few years, the virus had been identified throughout Europe and Russia. The virus was implicated in an outbreak of HFRS in Croatia during the Balkan Wars. The main region affected by DOBV is southeastern Europe, but its distribution has been expanding since its hosts extend outside the region.