Seroprevalence of Yellow Fever virus in selected health facilities in Western Kenya 2010–2012

Abstract

Yellow fever (YF), a mosquito-borne virus, is an important viral hemorrhagic fever endemic in equatorial Africa and South America. Yellow fever virus (YFV) is the prototype of the family Flaviviridae and the genus Flavivirus. The aim of this study was to determine the seroprevalence of YFV in selected health facilities in Western Kenya during the period 2010-2012. A total of 469 serum samples from febrile patients were tested for YFV antibodies using in-house IgM-capture ELISA, in-house IgG indirect ELISA and focus reduction neutralization test (FRNT₅₀). The present study did not yield any IgM ELISA positive cases an indication of absence of recent YFV infection in the area. Twenty eight samples (6%) tested positive for YFV IgG. These 28 cases detected during the study were due to either YFV vaccination or past exposure to various flaviviruses including YFV. There were five cases confirmed by FRNT₅₀, of these, four cases were either vaccination or natural infection during YF outbreak (1992-93) or another period and one case was confirmed as a West Nile virus infection. The domestication and routine performance of arboviral differential diagnosis will help to address the pyrexia of unknown origin phenomenon, arboviral research in developing countries and enhance regular surveillance.