On September 12 2008, Cecilia van Deventer, a safari booking agent living in Zambia, was flown to South Africa in critical condition. She died just two days later. By October 6 2008, three more people had died: the paramedic who accompanied Cecilia to South Africa, the nurse who cared for her in Intensive Care, and the cleaner who cleaned her hospital room after her death. A fifth patient, a nurse who cared for the infected paramedic, is receiving anti-viral treatment. In all cases, people infected were exposed to infected blood and/or body fluids.

South Africa's National Institute for Communicable Diseases (NICD) and the US Centers for Disease Control and Prevention (US-CDC) quickly identified the infectious agent as an arenavirus similar to the one that causes Lassa Fever - a disease that affects 500 000 people per year in West Africa. Now, following full sequencing of the viral genome by Professor Ian Lipkin and colleagues at the Center for Infection and Immunity (CII) at Columbia University, it has been clearly shown that this is an arenavirus that has never been seen before. Google.org's Predict and Prevent initiative recently announced a grant of $2.5 million to support CII's work in pathogen discovery. This identification of a novel arenavirus not only represents an early success, but also demonstrates just why this work is so important. 'There is no doubt we are dealing with a newly emerged virus,' said Dr. Janusz Paweska, head of the special pathology unit at the NICD in Johannesburg. As Professor Robert Swanepoel, also of the NICD, has pointed out, the virus is 'newly-discovered' rather than new, and has probably been around in animal populations for some time before making a recent jump to humans.

Arenaviruses, normally transferred to humans through contact with the urine of their rodent hosts, can be classified into New and Old World viruses depending on whether they originate in the Western or Eastern hemisphere respectively. New World arenaviruses, including Junin, Machupo, Sabia and Guanarito, can cause viral hemorrhagic fever. This particular virus, classified as Old World due to its African origins, began as a flu-like illness, then caused diarrhea, pharyngitis and a rash before rapidly culminating in respiratory distress, neurological symptoms and circulatory collapse over a period of about 9-12 days. The virus has yet to receive a name.

Due to the swift action of the NICD, US-CDC and CII the outbreak is now described as contained. We commend their efforts!