Sunday, October 16, 2016

Yellow Fever Outbreak in Angola and D.R. Congo is Being Controlled, According to WHO - Phase II Vaccination Campaign Begins in Angola

An outbreak of yellow fever in Angola and the Democratic Republic of the Congo is now under control, according to the World Health Organization. The first cases were reported in Angola in December 2015, and in March, the Democratic Republic of the Congo also reported cases connected to the Angolan outbreak. The WHO director general visited Angola in April and declared the outbreak "the most serious outbreak of yellow fever that Angola has faced in 30 years". Vaccines first arrived in Angola in January and in DRCongo in March, and vaccine campaigns have been ongoing since then. In Angola alone, there have been at least 3,800 cases and 369 deaths.

The Phase II vaccination campaign began on October 10 in Angola to vaccinate 2 million people in 12 high-risk districts in 10 Angolan provinces. The last confirmed case in Angola had a June 23rd symptom onset date, but there have been 42 probable cases reported in the last 4 weeks. In D.R. Congo, the last confirmed non-sylvatic case had symptom onset on July 12, but 16 probable cases are currently under investigation. A reactive vaccine campaign is also ongoing in D.R. Congo. WHO has sent over 30 million doses of yellow fever vaccine to Angola, D.R. Congo, and Uganda (which had its own outbreak this year).

Yellow fever is a viral hemorrhagic disease caused by the yellow fever virus. It is a member of the Flaviviridae RNA virus family and is related to West Nile and Japanese encephalitis viruses. The vaccine for yellow fever virus is quite effective, conferring lifelong protection within 30 days to 99% of individuals vaccinated. The transmission cycle for the virus is illustrated below, and occurs in three phases: the sylvatic phase, between mosquitoes and primates; the savannah phase, between humans at the forest edge, non-human primates, and mosquitoes; and the urban phase, between humans and urban mosquitoes.

 Yellow fever virus has three transmission cycles: jungle (sylvatic), intermediate (savannah), and urban.

Sources: 16 Oct 2016

- posted by Julia Daniel

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