South Africa: Rift Valley Fever reported in two provinces

An outbreak of Rift Valley Fever (RVF) in two South African provinces has killed one person, while five others have tested positive for the disease, which has also caused "extensive livestock deaths", the National Institute for Communicable Diseases (NICD), said in a statement on 9 March.

As of 4 March 2010, the livestock disease - which can be transmitted to humans by handling infected animal tissue during butchering - had been reported on 14 farms in Free State and one farm in the neighbouring province of Northern Cape.

Initial estimates by veterinarians in the affected region are that more than 1,000 livestock have perished. High mortality rates are experienced among young animals and the disease causes pregnancies to be aborted.

NICD director Dr Lucille Blumberg told IRIN the authorities had responded well to the outbreak, but RVF was "difficult to control", and "lots of rain recently" had resulted in ideal breeding conditions for mosquitoes - the vector of the disease.

Investigations were being carried out by the health and agricultural departments, supported by the South African Field Epidemiology and Training Programme, and NICD.

Endemic disease

Outbreaks of RVF are common; in 2009 more than 50 animals died in KwaZulu-Natal Province, but the most serious occurrence of the disease in South Africa was between 1974 and 1976, when an estimated 10,000 to 20,000 humans were infected.

"The current outbreak is within the same area, highlighting the importance of timely interventions to prevent further spread," the NICD said.

Blumberg said the disease was "asymptomatic", or mild, in the vast majority of people, but about one percent of those infected could experience a more severe reaction.

According to the NICD website, "complications include: ocular (retinal) disease, meningo-encephalitis, [and] or haemorrhagic fever. Onset of retinal lesions usually occurs one to three weeks after the first symptoms appear, and may lead to permanent loss of vision, necessitating continual follow-up of patients for a one-month period after symptoms resolve. Disease is rarely fatal."

Molefi Sefularo, the deputy minister of health, said in a statement on 8 March that "A 45-year-old patient, who was admitted to a mine hospital on 26 February 2010 with a provisional diagnosis of Congo fever, died a day later and confirmation of RVF was made on the 4th of March."

RVF was first identified by a British veterinary surgeon in Kenya more than 50 years ago, and is endemic to South Africa and the rest of the continent, as well as the Indian Ocean islands of Comoros and Madagascar.

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