Prospective case-control analysis of the aetiologies of acute undifferentiated fever in Vietnam

Le-Viet, Nhiem; Le, Viet-Nho; Chung, Hai; Phan, Duc-Tuan; Phan, Quang-Duong; Cao, Thanh-Van; Abat, Cédric; Raoult, Didier; Parola, Philippe

For each patient, 200 µL of whole blood and 200 µL of urine were used for DNA extraction, and 200 µL of acute-phase plasma and 200 µL of the throat swab sample in viral transport media were used for DNA/ RNA extraction. The eschar specimens were pretreated and used for DNA extraction as previously described [26] . DNA extraction using the DNA EZ1 extraction kit and DNA/RNA extraction using the EZ1 Virus Mini Kit v2.0 (Qiagen, Hilden, Germany) were performed with the EZ1 Advanced XL Robot (Qiagen) according to the manufacturer's instructions. The DNA and DNA/RNA products were either immediately used or stored at −20°C and at −80°C until molecular analysis, respectively. To avoid crosscontamination, the nucleic acid-extracting EZI Advanced XL Robot was disinfected after each batch of extraction based on the manufacturer's recommendations.