Outbreak of Rift Valley Fever in Sudan

Released: December 21, 2007

The Public Health Agency of Canada (PHAC) continues to monitor an outbreak of Rift Valley fever (RVF) in Sudan, Africa. Infection with RVF, although rare among travellers, can cause severe disease in both animals and humans, leading to high rates of disease and death. There are specific precautions that travellers can take to reduce their risk of contracting RVF – see ‘Recommendations’ below.

As of December 19, 2007, 601 human cases, including 211 deaths, have been reported from the States of White Nile, Seenar, Gazeera and River Nile. A small number of cases have also been reported in the State of Khartoum; however, it is likely that infection occurred in other affected areas. The extent of RVF infection in the local animal population is not yet well defined. 

Source: World Health Organization (WHO)

Rift Valley Fever

RVF virus primarily affects domestic livestock including cattle, goats, and sheep. The virus can be transmitted to humans through the bite of an infected (day-time or night-time biting) mosquito and possibly other biting insects, or through contact with blood or body fluids of infected animals.  Infection can also occur in humans through the slaughtering and handling of infected animals or through the preparation of meat or ingestion of raw milk from infected animals.

RFV is known to occur throughout many countries of sub-Saharan and North Africa, although outbreak activity has primarily occurred in the eastern and southern regions of Africa, where sheep and cattle are raised. In 2000, outbreaks of RVF were confirmed in Saudi Arabia and Yemen, representing the first incidence of documented transmission of the disease among humans and animals outside of Africa. 

Symptoms of RVF primarily range from no symptoms to a mild flu-like illness with the sudden onset of fever; most individuals recover within two days to one week following the onset of illness.  While the majority of human cases are relatively mild, a small proportion of patients develop much more severe manifestations of the disease – including haemorrhagic fever, meningoencephalitis (swelling of the brain), or ocular diseases.  Approximately one per cent of human cases of RVF are fatal.

There is no specific treatment for Rift Valley Fever, and no vaccine for humans.

Recommendations for travellers

Given the current outbreak situation, travellers to Sudan are at increased risk of RFV. PHAC recommends that travellers take the following precautions to reduce their risk of infection.

• Use personal insect protective measures to avoid insect bites. Comprehensive information on insect-bite avoidance is detailed in the Committee to Advise on Tropical Medicine and Travel’s “Statement on Personal Protective Measures to Prevent Arthropod Bites.” 
• Avoid contact with domestic animals such as cows, goats and sheep and take precautions to avoid coming into contact with the blood, organs or body fluids of such animals.
• Avoid handling raw meat.
• Avoid ingesting raw (unpasteurized) milk and milk products.

As a reminder…

PHAC strongly recommends that Canadian travellers consult their personal physician or a travel clinic at least six weeks prior to international travel, regardless of destination, for an individual risk assessment to determine their individual health risks and their need for vaccination, preventative medication, and personal protective measures.

PHAC recommends, as well, that travellers who become sick or feel unwell on their return to Canada should seek a medical assessment with their personal physician. Travellers should inform their physician, without being asked, that they have been travelling or living outside of Canada, and where they have been.

Additional Information

• World Health Organization – Rift Valley Fever

• For Foreign Affairs and International Trade Canada Travel Report on Sudan