DENGUE VIREMIA AND DENGUE SEROPREVALENCE IN BLOOD DONORS, BANGKOK, THAILAND

Dengue virus (DENV) infection is a major public health problem worldwide. Dengue clinical manifestations may range from asymptomatic, to mild symptomatic, and to a life-threatening shock syndrome. In endemic countries including Thailand blood donations from asymptomatic dengue infected persons pose a risk for DENV transmission. We investigated the prevalence of dengue viremia and dengue immunity among Thai blood donors (n = 400) from August 2015 to March 2016 using nested RT-PCR and anti-DENV IgM/IgG capture ELISA. Only one donor was positive for dengue virus serotype 2 (DENV2) viremia as revealed by RT-quantitative PCR and virus isolation. After a two-month follow up, the donor did not develop symptoms related to DENV infection and anti-DENV IgG and IgM levels remained just above and below cut-off values, respectively and were unchanged from the day of blood donation. In dengue serological studies, anti-DENV antibody ELISA was positive for IgG in 246 (61%) and both IgG and IgM in 24 (6%) of blood donors, respectively. In conclusion, the prevalence of detectable dengue (DENV2) viremia in blood donors in Bangkok was 0.25% but there still exists concern in dengue endemic regions of a finite risk of infection from blood transfusions. Further studies with a larger sample size will be required to evaluate the cost-benefit of an additional measure to detect dengue viremia in blood donations in Thailand.