BUNYAVIRUSES

Bunyaviruses belong to a large family of more than 200 viruses, most of which are arthropod-borne.

Congo-Crimean haemorrhagic fever

This is found mainly in Asia and Africa. The primary hosts are cattle and hares and the vectors are the Hyalomma ticks. Following an incubation period of 3-6 days there is an influenza-like illness with fever and haemorrhagic manifestations. The mortality is 10-50%.

Hantaviruses

Hantaviruses are enzootic viruses of wild rodents which are spread by aerosolized excreta and not by insect vectors. The most severe form of this infection is Korean haemorrhagic fever (or haemorrhagic fever with renal syndrome - HFRS). This condition has a mortality of 5-10% and is characterized by fever, shock and haemorrhage followed by an oliguric phase. Milder forms of the disease are associated with related viruses (e.g. Puumala virus) and may present as nephropathia epidemica, an acute fever with renal involvement. It is seen in Scandinavia and in other European countries in people who have been in contact with bank voles. In the USA, a new hantavirus (transmitted by the deer mouse) termed Sin Nombre was identified as the cause of outbreaks of acute respiratory disease in adults, referred to as hantavirus pulmonary syndrome (HPS). Other hantavirus types and rodent vector systems have been associated with this syndrome.

Diagnosis of hantavirus infection is made by an ELISA technique for specific antibodies.