Arenavirus (or Lassa virus, LASV) particles budding from a cell, illustration. This virus mainly infects rodents, but can infect humans through exposure to infected rodent faeces or urine. It is endemic in West Africa and South America, and causes haemorrhagic fever. Each virus particle consists of a single-stranded RNA (ribonucleic acid, pink) genome surrounded by a protein coat (capsid, blue). This protein capsid is surrounded by an envelope (pale green) covered in a single type of glycoprotein spike known as GPC (purple).