Epidemiological Analysis of Yellow Fever Disease in Angola from December 2015 through December 2016

Background: In December 2015, an outbreak of yellow fever virus (YFV) infection was reported in Angola, characterized by fever and jaundice, with at least one of the following symptoms: headache, asthenia, conjunctivitis, vomiting, with a different type of haemorrhage. Methods: A total of 4,618 cases of yellow fever (YF) were referred to the national referral laboratory of the Instituto Nacional de Investigação em Saúde, from December 5, 2015 through December 23, 2016 that were analyzed using ELISA, and subsequently samples were confirmed using consensus primers for RT-PCR assay. Results: We detected 884 (4%) cases that were positive on ELISA and RT-PCR assays. Patients were reported from 16 provinces of Angola. The incidence was approximately three times as high among male patients (10.88% per 100,000) than among female patients (2.65% per 100,000) in the 20 to 29 age group. Conclusions: This study represents the transmission of YFV human-to-human via the bite of the infected vector. The re-emergence of YFV is a huge concern for a national public health system. Thus, laboratory and public health surveillance systems have to be strengthened to alleviate the risk of re-emerging human infections.