The number of people who have died after contracting Rift Valley Fever has increased to five.

This after the three latest deaths were confirmed by the National Institute of Communicable Diseases at the weekend.

So far 82 people have been diagnosed with the fever, including the five who have since died.

RVF was first detected in February. The first few cases were reported in Free State and later spread to Northern Cape.

Department of Health spokesperson Charity Bhengu said: "Eighty-two human cases of RVF in South Africa, 66 of them including four deaths were reported in Free State.

"Another five from the Eastern Cape, 10 from the Northern Cape and one from North West. The Department of Health, Department of Agriculture, Forestry and Fisheries supported by the South African Field Epidemiology and Training Programme and NICD will continue to respond to the outbreak," Bhengu said.

RVF is a viral disease that can cause severe disease in a low proportion of infected humans. The virus is transmitted by mosquitoes and causes outbreaks of abortion and deaths of young livestock (sheep, goats and cattle). Symptoms include sudden onset of flu-like fever, muscle pain, neck stiffness, sensitivity to light, loss of appetite and vomiting.

"Direct contact with RVF-infected livestock and, or linked to farms with confirmed animal cases of RVF, remain the main risk factor for the infection. The human cases are farmers, veterinarians and farmworkers. Additional suspect cases are being tested," Bhengu said.

Affected farms are primarily clustered within Free State (initially in Lejweleputswa District, Bultfontein area). The Eastern Cape, Gauteng, Northern Cape and North West have also reported RVF among animals.