Arenavirus

A family of viruses that includes the viral hemorrhagic fevers such as Lassa fever, Argentine hemorrhagic fever, Venezuelan hemorrhagic fever, Brazilian hemorrhagic fever, and Bolivian hemorrhagic fever.

Arenaviridae

• The Arenaviridae are a family of viruses whose members are generally associated with rodent-transmitted diseases in humans.
• Each virus usually is associated with a particular rodent host species in which it is maintained.
• Arenavirus infections are relatively common in humans in some areas of the world and can cause severe illnesses.

Features of the viruses

• The virus particles are spherical and have an average diameter of 110-130 nanometers.
• All are enveloped in a lipid (fat) membrane.
• Viewed in cross-section, they show grainy particles that are ribosomes acquired from their host cells.
• It is this characteristic that gave them their name, derived from the Latin “arena”, which means “sandy”.
• Their genome, or genetic material, is composed of RNA only, and while their replication strategy is not completely understood, we know that new viral particles, called virions, are created by budding from the surface of their hosts’ cells.

Arenavirus history

• The first Arenavirus, Lymphocytic choriomeningitis virus (LCMV), was isolated in 1933 during a study of an epidemic of St. Louis encephalitis. Although not the cause of the outbreak, LCMV was found to be a cause of aseptic (nonbacterial) meningitis.
• By the 1960s, several similar viruses had been discovered and they were classified into the new family Arenaviridae.
• Since Tacaribe virus was found in 1956, new Arenavirus have been discovered on the average of every one to three years.
• A number of Arenavirus have been isolated in rodents only, but few cause hemorrhagic disease.
• Junin virus, isolated in 1958, was the first of these to be recognized.
• This virus causes Argentine hemorrhagic fever in a limited agrigultural area of the pampas in Argentina.
• Several years later, in 1963, in the remote savannas of the Beni province of Bolivia, Machupo virus was isolated.
• The next member of the virus family to be associated with an outbreak of human illness was Lassa virus in Nigeria in 1969. The most recent additions to these human pathogenic viruses were Guanarito detected in Venezuela in 1989, Sabia in Brazil in 1993, Chapare in Bolivia in 2004, and Lujo in South Africa in 2008.

Arenaviruses groups

Arenavirus are divided into two groups: the New World or Tacaribe complex and the Old World or LCM/Lassa complex. Viruses in these groups that cause mild or severe illness in humans and are listed below by date of discovery:

Arenaviruses that cause human diseases

Virus	Disease	Year discovered
Lymphocytic choriomeningitis virus (LCMV)	Lymphocytic choriomeningitis	1933
Junin virus	Argentine hemorrhagic fever	1958
Machupo virus	Bolivian hemorrhagic fever	1963
Lassa virus	Lassa fever	1969
Guanarito virus	Venezuelan hemorrhagic fever	1989
Sabia	Brazilian hemorrhagic fever	1993
Chapare	Chapare hemorrhagic fever	2004
Lujo	Lujo hemorrhagic fever	2008