While the Americas deal with their recent explosion of Zika cases, in Africa it is Yellow Fever (YF) making headlines, as Angola struggles with its largest outbreaks in 3 decades (see CDC Travel Notice For Angola - Yellow Fever) amid a serious vaccine shortage.
Complicating matters, with an incubation period of 3 to 6 days (cite CDC's Yellow Book), it is very easy for unvaccinated infected travelers to carry the virus to other countries where competent mosquito vectors may also be found.
A little over two weeks ago, in Yellow Fever In Angola & The Risk Of International Spread - ECDC, we looked at concerns of seeing this arbovirus spread well beyond Angola, and last week, in WHO Yellow Fever Update - Imported Cases In China, we looked at the risks posed by the recent spate of cases exported to China.
Yesterday the WHO published the following update, detailing more than 150 suspected YF cases detected in Angola's neighbor to the north, the Democratic Republic of Congo (DRC).
While the information to date indicates these are imported cases, the DRC has the right mosquito vectors, a suitable climate, and a history of seeing autochthonous YF cases, making the risks of seeing local transmission very real.
On 22 March 2016, the National IHR Focal Point of the Democratic Republic of Congo (DRC) notified WHO of cases of yellow fever (YF) in connection with the outbreak currently occurring in Angola.
From early January to 22 March 2016, a total of 151 suspected cases of YF, including 21 deaths (CFR: 14%), were reported by the national surveillance system.
Of the 151 suspected cases, 9 were confirmed by serology (IgM) at the Institute National Biomedical Research (INRB) in Kinshasa. Given possible cross-reactions with other arboviruses, IgM positive samples were sent to the Pasteur Institute of Dakar for confirmation where 4 tested positive for the infection. Of the 4 cases confirmed in Dakar, 3 were imported from Angola and were detected in the areas of Nsona-Pangu, Kimpese and Kitona in Kongo Central province (formerly, Bas-Congo), DRC. This province shares borders with Angola.
Public health response
The Ministry of Health of DRC has activated the National Committee for outbreak management to respond to this event. Undertaken activities include the establishment of coordination mechanisms, social mobilization and community engagement, strengthening surveillance through the training of health workers, dissemination of case definitions, screening and sanitary controls at Points of Entry and screening of refugees’ vaccination status. Other activities are targeting the vaccination of all individual travelling to Angola, strengthening vector control and case management.
With support from WHO and partners, the country has developed a contingency plan to improve the country's preparedness for a possible response to cases imported from Angola. A field visit of a national multidisciplinary team in Kongo central is planned in order to organize in-depth investigations of cases and enhance the preparation of the reactive immunization strategy.
WHO risk assessment
DRC is located in a geographical area known to be YF endemic and autochthonous cases are regularly reported. Since January 2016, autochthonous suspected cases have been recorded in the provinces of Bas-Uele, Equateur, Kasai central, and Tshuapa.
The report of yellow fever infection in travellers returning from Angola, however, highlights the risk of international spread of the disease. At this stage, the available information does not suggest the establishment of a cycle of transmission in DRC.
Nevertheless, the presence of the competent vector (the Aedes aegypti mosquito), the high proportion of individuals susceptible to the infection, and the intensity of population movements from and to Angola pose a serious risk of further spread of the disease in DRC.
WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.
WHO urges Members States especially those where the establishment of a local cycle of transmission is possible (i.e. where the competent vector is present) to strengthen the control of immunisation status of travellers to all potentially endemic areas.
WHO does not recommend any travel or trade restriction to DRC based on the current information available.
While we don't know yet if it's related to the Angola outbreak, late yesterday ProMed Mail carried a first hand report of YELLOW FEVER - AFRICA (36): UGANDA (MASAKA).
Hopefully we'll get more details in the next few days.