Junin virus is a New World arenavirus that causes Argentine hemorrhagic fever. This enveloped virus has a bi-segmented, single-stranded RNA genome and is primarily carried by Calomys musculinus rodents in Argentina. Human infection occurs through inhalation of aerosolized excreta from infected rodents.
Explanation
Junin virus belongs to the genus Mammarenavirus in the family Arenaviridae. Its virions are roughly 50–300 nm and pleomorphic with an envelope derived from the host membrane. The genome consists of two RNA segments: the small segment encodes the nucleoprotein and glycoprotein precursor, while the large segment encodes the RNA‑dependent RNA polymerase and a zinc-binding protein; both segments use an ambisense coding strategy. The virus is endemic to rural Argentina, where it circulates among maize-eating field mice (Calomys musculinus). Human disease follows inhalation of aerosolized rodent urine or feces. After an incubation period of 6–14 days, patients develop fever, malaise, facial flushing and petechiae. Without treatment the illness can progress to bleeding, shock and neurological manifestations. Prior to vaccination programmes the case fatality approached 15–30 %, but timely supportive care and use of plasma from immune donors or ribavirin have reduced mortality.
Outbreaks and control measures
Argentine hemorrhagic fever was first recognised in the 1950s when outbreaks occurred among agricultural workers in the Pampas region. The disease was initially associated with high fatality and neurological sequelae, prompting development of the live‑attenuated Candid #1 vaccine. Vaccination campaigns in endemic provinces have dramatically reduced the incidence of Junin virus infection. Laboratory studies show that the virus can be neutralised by passive transfer of immune plasma, and ribavirin therapy appears beneficial when given early. Control efforts focus on reducing rodent exposure in grain storage facilities and educating rural communities. Junin virus remains a notable example of a New World arenavirus causing severe haemorrhagic fever. Understanding its rodent reservoir and transmission routes has enabled successful control measures and vaccine development. Ongoing surveillance ensures early detection of cases and prevents resurgence. Related Terms: Lassa virus, Machupo virus, Guanarito virus, Sabia virus, Chapare virus