What are bunyaviruses and how they affect us


Most bunyaviruses are transmitted by arthropods. They comprise the genera Bunyavirus, Phlebovirus, Nairovirus and Hantavirus.

The genus Bunyavirus (type virus Bunyamwera)

This group contains 138 viruses in 18 antigenic groups. Most important are the California encephalitis group viruses such as LaCrosse virus, which are transmitted by mosquitoes. In the Simbu antigenic group Oropouche virus is one of the few midge-transmitted viruses that cause human epidemics (in Brazil).

The genus Phlebovirus

This genus has 37 members. The most important phlebovirus is probably Rift Valley fever virus, which has caused largescale epizootics and human epidemics of febrile illness, sometimes with haemorrhagic fever, in sub-Saharan Africa; it is transmitted to humans by Aedes mosquitoes, in which (like California encephalitis virus) it can be maintained by transovarial transmission (in the eggs). Most other viruses in the group are associated with phlebotomine sandflies. The Uukuniemi group viruses are tick-associated.

The genus Nairovirus

This includes Crimean-Congo haemorrhagic fever virus, which is transmitted from animals to humans by ticks, in the republics of the former Soviet Union, the Middle East and Africa, and causes severe haemorrhagic fever.

The genus Hantavirus

Hantaviruses differ from other bunyaviruses in being parasites of rodents. Hantaan virus and related viruses cause haemorrhagic fever with renal syndrome, which has occurred in outbreaks in Korea (hence its alternative name, Korean haemorrhagic fever), Manchuria and Eastern Europe. The infection causes severe capillary congestion, leakage and haemorrhage, especially in the renal medulla, so that oedema and acute renal failure develop, with oliguria and the passage of cells and protein in the urine. If the infection is left untreated, mortality is high, but with proper treatment for acute renal failure and blood transfusion if necessary, patients should recover. A less severe form of the disease, nephropathia epidemica, is found in Scandinavia.

Another hantavirus disease, hantavirus pulmonary syndrome, was first recognised in an outbreak in the southWest United States in 1993; a hantavirus transmitted from the deer mouse caused an outbreak of severe respiratory illness with features of acute respiratory distress syndrome.

Concepts of infection
Major manifestations of infection
Principles of management of infection
Diseases due to viruses
DNA viruses
Diseases due to chlamydiae
Diseases due to rickettsiae
Diseases due to bacteria
  • Streptococcal infections
  • Staphylococcal infections
  • Corynebacterial infections
  • Bacillus infections
  • Bordetella infections
  • Salmonella infections
  • Food poisoning
  • Dysentery
  • Other true bacterial infections
  • Mycobacterial infections
Diseases due to spirochaetes
  • Leptospira infections
  • Borrelia infections
  • Treponema infections
Diseases due to fungi (mycoses)
  • Cutaneous fungal infections
  • Subcutaneous fungal infections
  • Systemic fungal infections
Diseases due to protozoa
Diseases due to helminths
  • Trematode (fluke) infections
  • Cestode (tapeworm) infections
  • Nematode (roundworm) infections
  • Zoonotic helminth infections
Diseases due to arthropods
Sexually transmitted diseases
  • Sexually transmitted bacterial diseases
  • Sexually transmitted viral diseases
  • Miscellaneous conditions