12 March 2010

Rift Valley fever in Free State and Northern Cape provinces, South Africa

The National Institute for Communicable Diseases (NICD) in South Africa has reported an outbreak of Rift Valley fever (RVF) in animals and humans [1]. As of 4 March 2010, 14 farms in Free State province and one farm in Northern Cape province were affected, with extensive livestock deaths (sheep, goats and cattle) [1].

As of 8 March 2010, the South African Department of Health reported seven human cases of RVF with one death, in the same provinces where animal cases have been reported [2]. The six non-fatal cases have had mild disease and remain under observation. Most of the human cases reported direct contact with RVF virus-infected livestock. Investigation and control efforts have been implemented [1]. 

Sporadic cases of RVF have been documented within South Africa in recent years. The last major outbreak to affect the country occurred during 1974 to 1976 [1].

Rift Valley fever

RVF is a viral zoonosis that primarily affects cattle, goats and sheep, but can also infect humans. RVF virus is a virus of the family Bunyaviridae [3]. Infection can cause severe disease in animals, leading to high rates of illness and death.

The virus is transmitted to humans through contact with body fluids or organs of infected animals, or following a bite from an infected mosquito (most commonly Aedes spp and Culex spp mosquitoes).

The majority of cases of RVF in humans are asymptomatic or mild consisting of a self-limiting, febrile illness. About one percent of patients will develop severe manifestations including meningoencephalitis or haemorrhagic complications.

Advice for travellers

The risk to most travellers is low. Insect bite avoidance measures should be taken to avoid exposure to the mosquito vector. Those who may have contact with infected animals should ensure that appropriate personal protection measures are taken to prevent exposure to their blood and body fluids. Travellers should not consume milk or meat from potentially infected animals. There is no commercially available vaccine for humans.

Information on specific health risks for travellers to South African can be found on the NaTHNaC Country Information Pages.

References

1. National Institute for Communicable Diseases. Rift Valley Fever Virus Outbreak. Communicable Disease Comuniqué. 9:02, 2010. [Accessed 12 March 2010]. Available at http://www.nicd.ac.za/

2. Department of Health, South Africa. Statement by Deputy Minister of Health Dr Molefi Sefularo on the visit to the Free State Province to assess its readiness for 2010 FIFA World Cup & the Outbreak of Rift Valley Fever in that province. 8 March 2010. [Accessed 12 March 2010]. Available at: http://www.doh.gov.za/docs/pr/pr0308-f.html

3. World Health Organization. Rift Valley Fever fact sheet. Revised September 2007. [Accessed 12 March 2010]. Available at: http://www.who.int/mediacentre/factsheets/fs207/en/index.html

Links

U.S Centers for Disease Control and Prevention Questions and answers about Rift Valley fever

NaTHNaC Health Information Sheet on insect bite avoidance

NaTHNaC Country Information Page South Africa

NaTHNaC FIFA World Cup South Africa advice for UK football fans