''Argentinian mammarenavirus'', better known as the ''Junin virus'' or ''Junín virus'' (JUNV), is an

arenavirus An arenavirus is a bisegmented ambisense RNA virus that is a member of the family ''Arenaviridae''. These viruses infect rodents and occasionally humans. A class of novel, highly divergent arenaviruses, properly known as reptarenaviruses, have ...

in the ''

Mammarenavirus ''Mammarenavirus'' is a genus of viruses in the family ''Arenaviridae''. The name is a portmanteau of mammal and the former name ''Arenavirus'', and differentiates it from the reptile-associated ''Reptarenavirus''. ''Arenavirus'' comes from the ...

'' genus that causes

Argentine hemorrhagic fever Argentine hemorrhagic fever (AHF) 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'' (an ar ...

(AHF). The virus took its original name from the city of Junín, around which the first cases of infection were reported, in 1958.

Virology

Structure

''Argentinian mammarenavirus'' is a negative sense ssRNA enveloped virion with a variable diameter between 50 and 300 nm. The surface of the particle encompasses a layer of T-shaped glycoproteins, each extending up to 10 nm outwards from the envelope, which are important in mediating attachment and entry into host cells.

Genome

The ''Argentinian mammarenavirus'' genome is composed of two single-stranded RNA molecules, each encoding two different genes in an

ambisense In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context ...

orientation. The two segments are termed 'short (S)' and 'long (L)' owing 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 outwards from the viral envelope

The long segment (around 7200 nucleotides in length) encodes the viral polymerase and a zinc-binding protein. The virus is spread by rodents.

Disease and epidemiology

A member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

'', ''Argentinian mammarenavirus'' characteristically causes

(AHF). AHF leads to severe compromise of the

vascular The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...

neurological Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal c ...

and

immune In biology, immunity is the capability of multicellular organisms to resist harmful microorganisms. Immunity involves both specific and nonspecific components. The nonspecific components act as barriers or eliminators of a wide range of pathogens ...

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

conjunctivitis Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...

purpura Purpura () is a condition of red or purple discolored spots on the skin that do not blanch on applying pressure. The spots are caused by bleeding underneath the skin secondary to platelet disorders, vascular disorders, coagulation disorders, ...

, petechiae and occasionally

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

. The symptoms of the disease can be confusing; the condition can be mistaken for a different one, especially during the first week when it can resemble a

flu Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptom ...

. Since the discovery of ''Argentinian mammarenavirus'' in 1958, the geographical distribution of the pathogen, although still confined to Argentina, has expanded. At the time of discovery, ''Argentinian mammarenavirus'' was confined to an area of around 15,000 km². At the beginning of 2000, the region with reported cases grew to around 150,000 km². The natural hosts of ''Argentinian mammarenavirus'' are rodents, particularly ''Mus musculus'', ''Calomys'' spp. and ''Akodon azarae''. Direct rodent-to-human transmission only takes place when a person makes direct contact with the excrement of an infected rodent; this can occur by ingestion of contaminated food or water, inhalation of particles in urine or direct contact of an open wound with rodent feces.

Prevention and control

An investigational (in the US) vaccine (Candid1) was developed at the US Army Medical Research Institute for Infectious Disease ( USAMRIID) at Ft. Detrick, MD in the 1980s which has shown to be safe, well tolerated and effective in reducing mortality and morbidity due to AHF. The vaccine, which came from an XJ strain of the ''Argentinian mammarenavirus'', was continually passaged a total of 44 times in newborn mouse brains, and a total of 19 times along with cloning in FRhL cells. Over 90% of the volunteers in Phase 1 and 2 clinical trials developed antibodies against the ''Argentinian mammarenavirus'', and 99% developed an adequate immune response specific for ''Argentinian mammarenavirus''. Moreover, a large efficacy study among 6,500 people, where 3,255 individuals were randomly selected to take Candid 1 and 3,245 individuals were randomly selected to take a placebo resulted in 23 cases of Junin-like infections, where 22 out of the 23 cases were from the placebo group. This efficacy study resulted in a 95% vaccine efficacy. Currently, the Candid 1 vaccine, otherwise known as the Junin vaccine, is licensed in Argentina by the regulatory agency of Argentina where ''Argentinian mammarenavirus'' is endemic to the region. People in laboratories who come in constant contact with ''Argentinian mammarenavirus'' are also recommended to take the Junin vaccine to prevent transmission.Pittman, Phillip R., and Stanley A. Plotkin. (2013) "41 – Biodefense and Special Pathogen Vaccines." ''Biodefense and Special Pathogen Vaccines - Vaccines (Sixth Edition)''

References

{{DEFAULTSORT:Junin Virus Arenaviridae Rodent-carried diseases