[Serological, molecular and virological analyses associated with yellow fever surveillance in Colombia]

Yellow fever is an immunopreventable viral hemorrhagic fever that causes high morbidity and mortality in tropical and sub-tropical regions. In Colombia, approximately 5 million persons are at risk of becoming infected with yellow fever virus.

The serological, molecular and virological analyses on the yellow fever surveillance samples were summarized in order to indicate the importance of appropriate and timely sampling in the process of case confirmation.

The survey was based on samples received at the Arbovirus Laboratory, Virology Group, Instituto Nacional de Salud, Bogotá, during years 2006 to 2008. A total of 2,096 serum and tissue samples were tested for IgM antibodies against yellow fever by capture enzyme-linked immunosorbent assay, viral isolation-indirect fluorescence antibody technique, and reverse transcriptase-polymerase chain reaction. Positive samples were correlated with the clinical and epidemiological findings for their interpretation and confirmation.

Of the 15 yellow fever cases confirmed in Colombia during 2006-2008 by histopathological techniques, 82% were confirmed at the Arbovirus Laboratory using serologic and molecular techniques. The positive cases were distributed in the rainforest region and in the foothills of the eastern chain of the Andes mountains.

The case distribution and prognosis illustrated the necessity of maintaining and strengthening the surveillance processes in those regions where the yellow fever virus is circulating. The cases must be recruited and diagnosed sufficiently early in order to use the above techniques in samples from live patients, in contrast to the histopathological procedures that require samples from fatal cases.