Arenaviruses are a group of viruses that primarily infect rodents but can also be transmitted to humans. They are known for causing various diseases, including Lassa fever and Argentine hemorrhagic fever. Arenaviruses are characterized by their unique structure, which includes a segmented RNA genome and a lipid envelope. Transmission to humans typically occurs through contact with infected rodent excreta, urine, or saliva. Once infected, individuals may experience symptoms ranging from mild flu-like signs to severe hemorrhagic fever. Early diagnosis and supportive care are crucial for managing arenavirus infections effectively.