WHO EMRO Weekly Epidemiological Monitor: Volume 12, Issue 43 (27 October 2019)
Current major event
Rift Valley fever Sudan
The Federal Ministry of Health, Republic of Sudan has recently declared an outbreak of human Rift Valley Fever (RVF) in Red Sea State that started from September 24, 2019. Cases are now also being reported from River Nile and Khartoum states. A total 213 suspected cases, as well as six associated deaths have been reported till October 25, 2019. The outbreak has been laboratory-confirmed with 26 samples out of 29 collected testing positive for RVF.
Rift Valley Fever is a viral zoonosis that usually presents as mild illness, but may cause severe disease in both animals and humans leading to high morbidity and mortality. The disease was first identified in Kenya's Rift Valley in 1930.
Rift Valley Fever (RVF) is caused by a virus transmitted by mosquitoes and blood feeding flies that usually affects animals (commonly cattle and sheep) but can also involve humans, usually after handling, slaughtering or butchering infected animals. In humans, the disease ranges from a mild flu-like illness to severe haemorrhagic fever that can be lethal. When livestock are infected ith the disease, it can cause significant economic losses due to high mortality rate in young animals and waves of abortions in pregnant females.
This is not the first time that Sudan has experienced RVF outbreak. During the last two decades the country has faced a number of viral haemorrhagic fever outbreaks with high number of cases as well as high case fatality rates. Sudan reported a major outbreak in 2007 with 723 cases and 230 deaths (CFR 31.8%).
The outbreak of RVF reported from Red Sea State started during the last week of September 2019. Now the cases are also being reported from River Nile and Khartoum states. A total 213 suspected cases of RVF as well as six associated deaths have been reported from the affected states till October 25, 2019, with CFR 2.82%. In total there are six localities affected in three states. The cases are continuously reported from these three affected states and the number of reported cases got peak during the epidemiological week 42 of 2019. The age group of 45 and above is the most affected group (29.6 %), followed by the groups of 30 – 44 years (27.2%) and 15-29 with 26.8 % respectively. Only 14% of the cases occurred in age group 5-14 while under 5 years are approximately 3%. The outbreak has been laboratory-confirmed with 26 samples out of 29 collected testing positive for RVF.
The Ministry of Livestock and Fisheries in collaboration with other partners is responding to outbreak of RVF among animal in different states. There is strong coordination between partners working in health and animal sectors to enhance the surveillance to detect new cases both animal and humans, and implement appropriate interventions.
At this stage, it seems that the reported human case of RVF are only reported from these six localities. However, the presence of vector and evidence of RVF infection detected on and off from human and livestock during previous years. This has the ominous warning that the virus is circulating in animals in these areas. If this situation is not closely monitored and preventive and control measures put into place with immediate effect, there is a strong possibility that spread of the virus in other areas may escalate.