Angola: 2954 suspected cases

From the beginning of the outbreak on 15 December 2015 to 8 June 2016, Angola has reported 2954 suspected cases of yellow fever including 328 deaths. Among those cases, 819 have been laboratory confirmed. Despite extensive vaccination campaigns in several provinces, circulation of the virus persists.

As of 8 June 2016 three new provinces in Angola have reported local transmission, bringing the total number of districts with local transmission to 33 in 11 provinces, including Luanda.

The total number of reported cases in Angola increased from 11 April 2016 onward, while the number of laboratory confirmed cases remains stable. This can be attributed to the intensification of surveillance activities in most provinces.

Aedes aegypti Image/CDC
Aedes aegypti

Democratic Republic of The Congo: 57 laboratory confirmed cases

From the beginning of the outbreak on 22 March 2016 to 8 June 2016, the Democratic Republic of The Congo (DRC) has reported three probable cases and 57 laboratory confirmed cases: 51 of those are imported from Angola, reported in Kongo Central, Kinshasa and Kwango provinces, two are sylvatic cases in Northern provinces, and four are autochthonous cases in Ndjili and Kimbanseke districts, in Matadi (Kongo Central) and in Kwango province.

Uganda: 68 suspect cases

From the beginning of the outbreak on 9 April 2016 to 8 June 2016, the Ministry of Health of Uganda, has reported 68 suspected cases, of which three are probable and seven are laboratory confirmed. Confirmed cases have been reported from three districts: Masaka (five cases), Rukungiri (one case) and Kalangala (one case). According to sequencing results, those clusters are not epidemiologically linked to Angola.

The risk of spread

The virus in Angola and DRC is largely concentrated in main cities; however there is a high risk of spread and local transmission to other provinces in both countries. There is also a high risk of potential spread to bordering countries especially those previously classified as low-risk for yellow fever disease (i.e. Namibia, Zambia) and where the population, travellers and foreign workers are not vaccinated against yellow fever.

Three countries have reported confirmed yellow fever cases imported from Angola: DRC (51 cases), Kenya (two cases) and People’s Republic of China (11 cases). This highlights the risk of international spread through non-immunised travellers.

A further three countries have reported suspected cases of yellow fever: Ethiopia (one probable case), Ghana (four suspect cases) and Republic of Congo (one suspect case). Investigations are ongoing to identify the vaccination status of the cases and determine if they are linked with Angola. The two suspect cases previously reported in Sao Tome and Principe have been discarded.

Risk assessment

The outbreak in Angola remains of high concern due to:

  • Persistent local transmission in Luanda despite the fact that approximately 8 million people have been vaccinated.
  • Local transmission has been reported in 11 highly populated provinces including Luanda. Kuanza Norte, Luanda Norte, Cunene and Malenge are the provinces that most recently reported local yellow fever transmission.
  • The continued extension of the outbreak to new provinces and new districts.
  • High risk of spread to neighbouring countries. As the borders are porous with substantial cross border social and economic activities, further transmission cannot be excluded. Viraemic travelling patients pose a risk for the establishment of local transmission especially in countries where adequate vectors and susceptible human populations are present.
  • Risk of establishment of local transmission in other provinces where no autochthonous cases are reported.
  • High index of suspicion of ongoing transmission in hard-to-reach areas like Cabinda.
  • Inadequate surveillance system capable of identifying new foci or areas of cases emerging.