Yellow fever – Uganda

On 8 April 2016, the National IHR Focal Point of Uganda notified WHO of an outbreak of Yellow Fever (YF) in Masaka district, south of Kampala.

An alert concerning a suspected outbreak of viral haemorrhagic fever in Kaloddo village, Masaka district was initially sent on 26 March. A cluster of three cases from a single family was reported after patients presented with high-grade fever, were non-responsive to anti-malarial treatment with haemorrhaging signs and acute neurological signs (convulsions and unconsciousness).

From 28 March to 1 April, a rapid response team (RRT) was deployed to carry out investigation and response activities. The RRT confirmed the deaths, activated the district task force, set up a treatment facility in Masaka, and collected and referred samples to the Uganda Virus Research Institute (UVRI) for laboratory testing. In addition, the team used a case definition for haemorrhagic fevers and proceeded to carry out active case search to identify additional suspected cases.

On 29 and 30 March, 6 samples were sent to the UVRI and tested negative for all Ebola virus disease, Marburg virus disease, Crimean-Congo haemorrhagic fever, Rift Valley fever by polymerase chain reaction (PCR). On 8 April, Yellow Fever was confirmed on three samples by PCR, two blood samples tested positive for salmonella non-typhi and one tested positive for malaria. On 21 April, at least four samples were re-confirmed positive by PCR at CDC Fort Collins (WHO Collaborative Center for Yellow Fever).

From 26 March to 18 April, 30 cumulative suspected cases, including 7 deaths, were reported from Masaka, Rukungiri, Ntungamo, Bukumansimbi, Kalungu, Lyantonde, and Rakai. Of these, 6 cases and 2 deaths were confirmed in Masaka district (5 cases), and Rukungiri district (1 case). The mean age of the cases is 23 years old. The majority of cases are male. The cases do not have any history of travel outside of Uganda.

Public health response

The Ministry of Health of Uganda, with the support of WHO, Centers for Disease Control, Médecins Sans Frontières and other partners are supporting the response to the outbreak. WHO AFRO shared relevant guiding documents with the country for conducting risk assessment, vector control and outbreak management. The district task force which coordinates the response at district level developed a response plan and meets regularly. A multidisciplinary investigation team (physicians, laboratory experts, communication specialists, an epidemiologist and an entomologist) was sent to the affected district to conduct in-depth investigations and provide technical support to the District Task Force. Active surveillance has been enhanced through the activation of the alert desk and provision of alert free lines to the public. Case management, social mobilization, reactive vaccination and a rapid YF risk assessment are ongoing. A YF management centre was established in Masaka and Yellow Fever vaccine has already been requested from the International Coordinating Group on Vaccine Provision for reactive vaccination.

WHO risk assessment

The current outbreak in Uganda is occurring in the context of international export of YF cases from Angola to China, the Democratic Republic of the Congo, and Kenya. Uganda is situated in the “Yellow Fever belt” of Africa and is considered a country at risk of Yellow Fever virus transmission. Last outbreak of Yellow Fever was reported in December 2011. The affected districts are in south-western Uganda close to Democratic Republic of Congo, Rwanda and Tanzania. As the borders are porous with substantial cross border social and economic activities, further transmission cannot be excluded. WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.

WHO advice

WHO urges Members States especially those where the establishment of a local cycle of transmission is possible (i.e., where the Aedes spp mosquitoes are present) to strengthen the control of immunization status of travellers to all potentially endemic areas and the surveillance of potential YF cases.

WHO does not recommend any restriction of travel and trade to Uganda based on the current information available.