A new deadly virus
As the world's attention has been focussed on the global financial crisis, little notice has been taken of the emergence of a new deadly disease in southern Africa. In September a woman tourist guide living near Lusaka, Zambia was evacuated to South Africa in a critical state. Her symptoms included fever myalgia, vomiting, diarrhoea, followed by rash, liver dysfunction and convulsions. Within a few weeks she died of acute respiratory distress syndrome. A paramedic who had cared for the patient during the evacuation developed similar symptoms and died, as did an intensive care nurse who treated the patient. A fourth person also fell ill.
The culprit of this deadly disease appears to be an Arenavirus (Family Arenaviridae),. These are enveloped viruses with a bi-segmented negative strand RNA genome. The African and Old World arenaviruses (like Lassa fever virus) differ from the New World viruses such as Junin virus in their use of primary receptors. The prototype Arenavirus is Lymphocytic Choriomeningitis virus (LCMV) which can cause meningitis. Rodents such as mice and hamsters can harbour the virus and pass it on to humans. It is a potential problem particularly for pregnant women who should avoid handling pet (or laboratory) rodents. Other Arenaviruses cause haemorrhagic fever, such as Lassa fever virus, Guanarito virus, and Machupo virus. Lassa fever virus causes thousands of cases of disease each year throughout West Africa, with estimates of around 500 deaths a year. As with LCMV, these other viruses are also found in rodents, which act as reservoir hosts, and humans can contract the disease by contact with faeces, urine, blood or saliva of infected rodents.
The Arenavirus isolated from the recent South African cases of disease have yet to be identified, but could be a new virus. In a brief news item in the New Scientists there is a quote from Bob Swanepoel of the South African National Institute for Communicable Disease saying "how little we know about the viruses circulating in Africa". A look on the CAB Abstracts and Global Health Databases show that there is more than 800 records on this viruses. Of these over 200 are on Lassa fever virus. A brief look through these records helps to create a picture of the effect that these viruses are having, what the current state of knowledge is, and where the work is being done.
By looking through the records on CAB it appears that this outbreak in Africa is not the only recent case of Arenaviruses emerging and causing fatalities. Earlier this year another new Arenavirus was reported in a cluster of fatal cases associated with transplant complications in the USA. The virus in this cluster was found to resemble the LCMV virus*. Most of the new viral diseases, such as SARS, Nipah, and Hendra virus infection, that crop up in humans have crossed the species barrier and come from other animals. This would reinforce the importance of information across the medical and the veterinary areas in understanding and controlling these diseases.
*Arenavirus in a cluster of fatal transplant-associated diseases. Palacios, G. (et. al), New England Journal of Medicine, 2008, Vol. 358, No. 10, pp. 991-998.
Excellent research. Thank you.
Posted by: Becky McClain | October 22, 2008 at 02:23 AM