A febrile blood donor.

A 4-day-old neonate born prematurely at 29 weeks gestation developed thrombocytopenia (platelet count 43 10/L) with associated severe pulmonary and intracranial hemorrhaging. Urgent transfusions with 10 mL/kg of packed red cells and 10 mL/kg of platelet concentrate were given. These were sourced from blood donated 2 days earlier in Singapore by a 21-yearold female university student who was clinically well at the time. The day after these blood products were given to the neonate, the blood donor contacted the blood transfusion service to inform them that she was now sick with a febrile flu-like illness. Her blood donation screening plasma sample was retrieved and tested by PCR for several viruses, including dengue, chikungunya, enterovirus, and Epstein-Barr virus. Dengue RNA (serotype 2) was found to be present at a very low amount (i.e., at a real-time PCR cycle Ct number of 39 – 40) (Fig. 1A) from the initial RNA extract (extract A). To confirm the presence of this low amount of dengue 2 RNA, the same extract (extract A, which had been stored at 20 °C) was retested (Fig. 1B), and again found to give a low-positive result.