Morphology and genome structure

The Junin virus virion is enveloped

Viral envelope

Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...

 with a variable diameter of between 50 and 300 nm. The surface of the particle encompasses a layer of T-shaped glycoprotein

Glycoprotein

Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

 extensions, extending up to 10 nm from the envelope, which are important for mediating attachment and entry into host cells.

The Junin virus genome comprises two single stranded RNA molecules, each encoding two different genes in an ambisense

Sense (molecular biology)

In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...

 orientation. The two segments are termed 'short (S)' and 'long (L)' due to their respective lengths. The short segment (around 3400 nucleotides in length) encodes the nucleocapsid protein and the glycoprotein precursor (GPC). The GPC is subsequently cleaved to form two viral glycoproteins, GP1 and GP2 which ultimately form the T-shaped glycoprotein spike which extends from the viral envelope. http://virology.ifas.ufl.edu/course/Arenavirus.ppt#285,14,Slide14. The long segment (around 7200 nucleotides in length) encodes the viral polymerase

Polymerase

A polymerase is an enzyme whose central function is associated with polymers of nucleic acids such as RNA and DNA.The primary function of a polymerase is the polymerization of new DNA or RNA against an existing DNA or RNA template in the processes of replication and transcription...

 and a zinc binding protein. It is spread by rodents

Epidemiology and disease

A member of the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Arenavirus

Arenavirus

Arenavirus is a genus of virus that infects rodents and occasionally humans. At least eight Arenaviruses are known to cause human disease. The diseases derived from Arenaviruses range in severity. Aseptic meningitis, a severe human disease that causes inflammation covering the brain and spinal...

, Junin virus characteristically causes Argentine hemorrhagic fever

Argentine hemorrhagic fever

Argentine hemorrhagic fever or O'Higgins disease, also known in Argentina as mal de los rastrojos, stubble disease, is a hemorrhagic fever and zoonotic infectious disease occurring in Argentina. It is caused by the Junín virus...

 (AHF). AHF leads to major alterations within the vascular

Blood vessel

The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

, neurological

Nervous system

The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

 and immune

Immune system

An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

 systems and has a mortality rate of between 20 and 30%. Symptoms of the disease are conjunctivitis

Conjunctivitis

Conjunctivitis refers to inflammation of the conjunctiva...

, purpura

Purpura

Purpura is the appearance of red or purple discolorations on the skin that do not blanch on applying pressure. They are caused by bleeding underneath the skin...

, petechia

Petechia

A petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...

 and occasional sepsis

Sepsis

Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

. The symptoms of the disease are relatively indistinct and may therefore be mistaken for a different condition.

Since the discovery of the Junin virus in 1958, the geographical distribution of the pathogen, although still confined to Argentina, has risen. At the time of discovery, Junin virus was confined to an area of around 15,000 km². At the beginning of 2000, the distribution had risen to around 150,000 km². The natural hosts of Junin virus are rodents, particularly Mus musculus

House mouse

The house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....

, Calomys spp.

Vesper mouse

Calomys is a genus of rodents, also called vesper mice. The genus is widely distributed in South America.Some species are notable as the vectors of Argentinian hemorrhagic fever and Bolivian hemorrhagic fever.-References:...

 and Akodon azarae

Azara's Grass Mouse

Akodon azarae, also known as Azara's Akodont or Azara's Grass Mouse, is a rodent species from South America. It is found from southernmost Brazil through Paraguay and Uruguay into eastern Argentina. It is named after Spanish naturalist Félix de Azara.-Literature cited:*D'Elia, G. and Pardinas, U....

. Direct rodent to human transmission only transpires when contact is made with excrement of an infected rodent. This commonly occurs via ingestion of contaminated food or water, inhalation of particles within urine or via direct contact of broken skin with rodent excrement.