Detection of Dengue Virus in Samples from Suspected Yellow Fever Cases in Ghana

Background: Dengue fever remains a serious public health treat throughout the world. Ghana shares borders with countries that have reported dengue cases, yet no case has been reported in Ghana. Dengue infections with its broad range of clinical presentations make it potentially unrecognized by clinicians. In this study, serological tests were used to detect antigens and antibodies and molecular tests were used to detect viral RNA specific to dengue viruses in archived human serum specimens in Ghana.

Methods: Blood samples of 360 patients aged 6 months to 82 years old with suspected yellow fever in hospitals across Ghana were tested for dengue virus exposure. Samples were screened using SD Dengue NS1 Ag ELISA and the SD Dengue IgM/ IgG capture ELISA test, which detects dengue virus antigen and antibodies to dengue virus in human blood.

Results: A total of 360 serum samples were tested, 8% (29/360) were found positive by the antigen/antibody ELISA test, 2.5% (9/360) were positive by NS1 ELISA with 1.9% (7/360) and 3.6% (13/360) being positive by IgM and IgG ELISA respectively. None of the specimens tested positive by real-time RT-PCR. 0.6% (2/360) of cases tested positive for both NS1 and IgG. The proportion of NS1 antigen positivity was highest in the Brong Ahafo region 0.33 (3/9) followed by Ashanti and Upper West regions with 0.22 (2/9) respectively. IgM positivity was, however, highest in Upper West 0.43 (3/7).

Conclusion: Introduction of dengue virus surveillance with routine diagnosis will serve to alert the health system of the possible outbreak and also minimize spread in the event of an outbreak in the country.