Yellow fever (YF) remains an important public health problem in regions where the disease is endemic, with a dramatic upsurge in the number of cases in recent years. So far, extensive YF epizooties occurred in South America in 2008, and during the past year YF outbreaks arose in Cameroon, Democratic Republic of Congo, Guinea, Cote d'lvoire, Central African Republic, and Liberia (http://www.who.int/). Highly effective, live attenuated YF vaccines against the disease have been available for decades and have had a major impact on the incidence of the disease (17).The clinical diagnosis of isolated cases of YF or identification of vaccine-associated adverse events (YFVAE) is particularly difficult because the symptoms are quite similar to those of many other diseases (20). Laboratory confirmation is therefore essential and relies on the detection of YF-specific IgM or a 4-fold or greater rise in serum IgG levels (in the absence of recent YF vaccination), isolation of yellow fever virus (YFV), positive postmortem liver histopathology, detection of YF antigen in tissues by immunohistochemistry, or detection of YFV RNA by PCR, which provides the earliest diagnosis possible. Samples recommended for diagnostics are blood, serum, cere-brospinal fluid (CSF), peritoneal or pleural fluid, and liver biopsy specimens (1, 20). However, biopsies and invasive techniques must be avoided or practiced with extreme caution due to the risk of bleeding complications (5).
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