Arenaviridae

 The Arenaviridae are a group of viruses associated with rodent-transmitted disease in humans.  Each virus is associated with a particular rodent host that serves as the reservoir.  In specific areas of the world, these diseases are common in humans and can cause severe disease.

 Rodent that carries Arenaviruses
History
       In 1933, the first arena virus, lymphocytic choriomeningitis (LCMV) was isolated.  Prior to 1965, and the discovery of the Tacaribe virus, a new arenavirus has been isolated every three years.  The first arenavirus to cause hemorrhagic disease,  the Junin virus, was isolated in 1958.  This virus causes Argentine hemorrhagic fever. Since that time, several viral hemorrhagic fever pathogens have added to the family Arenaviridae.

Viral Characteristics
     The virus itself has been described in great detail.  The virus is spherical in shape with a diameter of 110-130 nanometers.  Single stranded RNA composes the viral genome and is encased in a lipid membrane.  When viewed in a cross section, the viral particle appears to be covered in grainy particles, which are the ribosomes acquired from the host cell.  The method of replication is not yet fully understood.  However, it is known that new viral particles are created through budding from the surface of the host cell.
Arenavirus budding from host cell.

Reservoirs
    The family Arenaviridae is broken into two groups:  The Tacaribe Complex Viruses and The LCM/Lassa Complex Viruses.  This division is based on the virus' natural reservoir.  The Tacaribe Complex Viruses are associated with New World rats and mice, belonging to the family Muridae and subfamily Sigmodontinae.  The natural reservoir of the  LCM/Lassa Complex Viruses is Old World rats and micee.  They belong to the family Muridae and subfamily Muridae.
 
Virus Diseases Group
Lassa Virus Lassa Fever LCM/ Lassa
Junin Virus Argentine Hemorrhagic Fever Tacaribe
Machupo Virus Bolivian Hemorrhagic Fever Tacaribe
Guanarito Virus Venezuelan Hemorrhagic  Tacaribe
Sabia Brazilian Hemorrhagic Fever Tacaribe

Transmission
    The rodent hosts of arenaviruses are chronically infected with the virus.  Some Old World arenaviruses are passed from mother rodents to their offspring.  On the other hand, New World arenaviruses are spread among adult rodent populations through fighting and biting.  Once a rodent is infected, it begins to pass the virus in its urine and droppings.
    Human infection occurs when an individual comes into contact with the urine and droppings of an infected rodent.  This could occur by ingestion of contaminated food or through direct contact of broken skin with rodent excretement.  The virus may also be aerosolized.  This occurs when air particles are contaminated with rodent urine.
    Some arenaviruses are associated with secondary person to person transmission.  This transmission occurs when a person comes in direct contact with the blood or excretions of an infected person.

Prevention
    Keeping food sealed and reducing rodent populations helps to limit contact with the disease carrying vectors.

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References:
Centers for Disease Control
 World Health Organization