To investigate Crimean-Congo hemorrhagic fever virus in Turkey, we conducted a seroepidemiologic survey during January–April 2009. Seroprevalence of infection was 10% in a sample from an outbreak region and increased with patient age, indicating that the virus had been previously present in Turkey. We also estimated that 88% of infections were subclinical.

Our results suggest that the nosocomial occurrence of IRAB is strongly related to an ICU stay and duration of hospital stay, and that IRAB occurrence may be favored by the selection pressure of previously used antibiotics.

Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal disease affecting multiple organ systems. To determine the association between viral load and severity of CCHF infection, quantitative measurement of CCHF virus was performed using 1-step reverse-transcriptase polymerase chain reaction for 36 patients with CCHF infection. Viral loads ranged from 1.1x10(3) copies/mL to > or = 9.9x10(9) copies/mL. Nine (25%) of 36 patients died. In 8 of the 9 patients with fatal outcomes, viral loads were detected that were > or = 1x10(9) copies/mL, whereas in 25 of the 26 patients with nonfatal outcomes, viral loads were detected that were < 1x10(9) copies/mL (P<.001). A viral load > or = 1x10(9) RNA copies/mL can be considered to predict a fatal outcome with a positive predictive value of 80%, with 88.9% sensitivity and 92.6% specificity. We suggest that viral load is a measure of the severity of CCHF.

Endothelial activation can affect the course of CCHF, and vascular endothelial damage is probably indirect. Further studies are needed for general conclusions to be drawn.

In this study, oral ribavirin treatment in CCHF patients did not affect viral load or disease progression.