South African doctors move quickly to contain new virus

When a microbiologist at a private laboratory requested assistance in a case of suspected viral haemorrhagic fever (VHF), alarm bells started ringing at the National Institute for Communicable Diseases (NICD) in South Africa. Dr Lucille Blumberg, head of the epidemiology division at the institute, said her team noted that the doctor who had treated this potential VHF patient, an adult male, had also treated a woman safari agent from Zambia. The woman had been suffering from fever, vomiting and diarrhoea, followed by rash, liver dysfunction and convulsions. On 12 September, she was evacuated in critical condition to a private clinic in Johannesburg. A day after being admitted, she died. It transpired that the suspected VHF case was a male paramedic who had become ill on 21 September, nine days after caring for the safari agent during her evacuation from Zambia. He died on 2 October. Blumberg's fears of a disease outbreak were heightened when a third case, a nurse who had treated the safari agent at the Johannesburg clinic, was admitted to hospital on 30 September. Five days later, she too was dead. "I thought there was something very wrong, something going on," said Blumberg, "and then on Thursday night we heard about the nurse who had been admitted." Two further cases were identified in October. One had cleaned the hospital room occupied by the safari agent, the index case in this outbreak. The cleaner died on 6 October. The fifth case was a nurse who had cared for the paramedic (case number two). This nurse was treated with ribavirin, which has been effective in patients with Lassa fever, and she has since made a good recovery. She was the only one of the five to receive this treatment because the virus had been identified by the time she became ill. All patients initially had non-specific flu-like illness. Symptoms included fever, headache and muscle pain. The illness increased in severity over a week, with the patients developing diarrhoea and pharyngitis. A rapid deterioration, with respiratory distress, neurological signs and circulatory collapse were terminal features in all four patients who died. Blumberg's fears that "something was very wrong" were borne out when the cause of the outbreak was found to be a distinct new strain of Old World arenavirus. This was established in tests done by the special pathogens unit (SPU) of the NICD at the National Health Laboratory Service in Sandringham, South Africa, the infectious diseases pathology branch of the Centers for Disease Control and Prevention (CDC) in Atlanta, USA, and Columbia University in New York. The new strain, which was isolated by SPU head Dr Janusz Paweska, is a distant relative of two Old World arenaviruses known to be pathogenic for humans: Lassa virus, which is common in western Africa, and lymphocytic choriomeningitis (LCM) virus, which can be found worldwide. But neither LCM virus nor Lassa fever virus has ever been found in southern Africa. The newly discovered virus is now the third Old World arenavirus species known to cause a severe and frequently fatal infection in humans. [ILLUSTRATION OMITTED] Arenaviruses are broadly divided into two groups: New World arenaviruses, found in the Americas; and Old World arenaviruses, found in Africa. Both are associated with rodents and have co-evolved with them. Rodents are common in village houses in western Africa and therefore human exposure to the virus can be frequent. That the outbreak has been contained to five people speaks volumes for the work of the provincial outbreak response teams in partnership with the NICD, which was formed in 2002 to gather intelligence on communicable diseases and provide expertise throughout the southern Africa region. Its epidemiology team was alerted to the problem early, while the SPU--a WHO Collaborating Centre for the research and diagnosis of VHFs and other viruses--was able to help identify this new species of Old World arenavirus. …