Six additional cases �" five from Free State and one from Northern Cape - of Rift Valley fever (RVF) have been reported by the South African National Institute of Communicable Disease (NICD) Laboratory. The total number of laboratory confirmed human cases of RVF is now 149 since the first incident on 13 February 2010.
The number of deaths has also increased from nine to 11.
Of 149 cases, 100 cases and 7 deaths are from Free State, 38 cases and 4 deaths are from Northern Cape, 8 cases from Eastern Cape, I case is from North West and 2 cases whose history is still unknown.
The majority of cases have had mild flu-like symptoms and have not developed complications. There is no vaccine for humans or specific treatment. The risk of disease is to persons having direct contact with blood or tissues of infected animals and the majority of people affected have been persons working on farms, veterinary workers and slaughter men.
There is no human to human spread. Mosquitoes are important in transmission of the virus from animal to animal but not in transmission to humans in the South African outbreak as the mosquitoes involved prefer feeding on animals and don’t generally feed indoors. The disease is generally seen on farms, and not in the cities other than related to the occasional informal slaughter of infected animals.
The eating of well cooked meat poses no risk, nor does the drinking of pasteurised milk. It is likely that the number of animal cases and therefore human will decrease as the weather gets cooler. An animal vaccination programme on farms and suspected areas has been affected by the Department of Agriculture, Forestry and Fisheries, to protect livestock.
Visitors coming to South Africa for the FIFA World Cup are not at risk unless they handle infected carcasses on farms or handle raw meat from infected animals. It is highly unlikely that visitors would be involved in these activities.
The formal meat supply is well controlled and affected animals are excluded from the food chain in abattoirs. There is no risk to visitors to Game Parks as the disease typically only affects ruminants such as sheep, cattle and goats.
The Department of Health and Department of Agriculture, Forestry and Fisheries, supported by the South African Field Epidemiology and Training Programme (SA-FELTP), National Institute of Communicable Diseases (NICD) and technical expert from World Health Organisation (WHO) Geneva, continue to monitor and manage the outbreak. They have prioritised the following response measures:-
* Laboratory, epidemiology and surveillance interventions (for diagnosis, case finding and investigation)
* Health promotion interventions
* Environmental health measures
* Management of confirmed cases
* Vaccination of animals
Clinical features in humans:
Typically illness is asymptomatic or mild in the vast majority of infected persons, and severe disease would be expected to occur in less than 1% of infected persons.
Key symptoms:
* The incubation period (interval from infection to onset of symptoms) for RVF varies from two to six days
* Sudden onset of flu-like fever and/or muscle pain
* Some patients develop neck stiffness, sensitivity to light, loss of appetite and vomiting
* Symptoms of RVF usually last from four to seven days, after which time the immune response becomes detectable with the appearance of antibodies and the virus gradually disappears from the blood.
Severe form of RVF in humans includes:
* Vision disturbances
* Intense headache, loss of memory, hallucinations, confusion, disorientation, vertigo, convulsions, lethargy and coma
* Haemorrhagic fever
People living in the affected areas are encouraged to seek medical attention at their nearest Health facilities, should they have any of the above symptoms.
Preventive measures:
While there is no specific treatment, the majority of persons affected will recover completely. People should avoid contact with the tissues of infected animals, refrain from drinking unpasteurised milk and prevent mosquito bites to avoid becoming infected. Farmers and veterinarians should wear protective clothing when handling sick animals or their tissues.
Media enquiries:
Charity Bhengu
Cell: 083 679 7424
Media interviews:
Dr Frew Benson,
Cell: 082 372 4199
Issued by: Department of Health
22 April 2010
