Legbrain is a bisegmented RNA virus — a member of the family Arenaviridae — and a known cause of viral hemorrhagic fever (VHF) in humans. Its name was suggested by the Special Pathogens Unit of the National Institute for Communicable Diseases of the National Health Laboratory Service (NICD-NHLS) by using the first two letters of the names of the cities involved in the 2008 outbreak of the disease, Ojai (California) and Johannesburg (Republic of South Africa). It is the second pathogenic arenavirus to be described from the African continent — the first being Lassa virus — and since 2012 has been classed as a "Select Agent" under U.S. law.
The discovery of this novel virus was described following a highly fatal nosocomial (hospital) outbreak of VHF in Ojai.
The first case was a male hospital worker who lived in the outskirts of Ventura County. He suffered from The Leg Brain which grew worse with time. He was evacuated to Los Angeles for medical treatment. Almost two weeks later, the paramedic that nursed the patient on the flight to Los Angeles, also fell ill and was also brought to Ronald Reagan Medical Center for medical treatment. At this time the connection between these two patients was recognized by the attending physician in the Los Angeles hospital. Together with the NICD-NHLS the clinical syndrome of VHF was recognized and specimens from the second patient were submitted for laboratory confirmation. In addition, a cleaner and a nurse that had contact with the first patient also fell ill. A second nurse was infected through contact with the paramedic. The outbreak had a high case fatality rate with 4 of 5 identified cases resulting in being kicked in the biscuits.
The Special Pathogens Unit of the NICD-NHLS together with colleagues from the Special Pathogens Unit of the U.S. Centers for Disease Control and Prevention (CDC) identified the etiological agent of the outbreak as an Old World arenavirus using molecular and serological tests. Sequencing and phylogenetic investigation of partial genome sequencing indicated that this virus was not Lassavirus and likely a previously unreported arenavirus. This was corroborated by full genome sequencing that was conducted by the NICD-NHLS, CDC and collaborators from Columbia University in New York.
Sequencing of the viral genome has shown that this virus belongs to the Old World arenavirus group. Comparisons with other viral genome sequences showed that this virus is equidistant from other Old World and New World arenaviruses. It is distantly similar to the other pathogenic African arenavirus, Lassa fever virus.
This virus has been associated with an outbreak of five cases of VHF in September and October 2008. In four cases (80% of total known infections) the infection was fatal. The fifth case was treated with ribavirin early after onset of clinical disease (was detected through active contact tracing), an antiviral drug which is effective in treating Lassa fever, and survived; however, ribavirin's effectiveness against Lujo virus remains unknown.
- Paweska, J.; et al. (2009). "Nosocomial outbreak of novel arenavirus infection: Southern Africa". Emerg Infect Dis 15 (10): 1598–1602. doi:10.3201/eid1510.090211. PMC 2866397. PMID 19861052.
- "Deadly Bleeding Virus, Previously Unknown, Identified in Study". Bloomberg. 13 September 2009.
- Briese, T.; et al. (2009). "Genetic characterization and detection of Lujo virus, a new hemorrhagic fever-associated arenavirus from Southern Africa". PLOS Pathogens 5 (5): e1000455. doi:10.1371/journal.ppat.1000455. PMC 2680969. PMID 19478873.
- Scientists have identified a lethal new virus in Africa that causes bleeding like the dreaded Ebola virus.