1. Department of Clinical Science/Obstetrics & Gynecology, Umeå University, SE-901 87 Umeå, Sweden
2. Department of Medical Biosciences/Pathology, Umeå University, SE-901 87 Umeå, Sweden
3. Public Health and Clinical Medicine, Nutritional Research, Umeå University, SE-901 87 Umeå, Sweden
4. Clinical Research Centre, Örebro University Hospital, SE-701 85 Örebro, Sweden
5. Department of Clinical Microbiology/Virology, Umeå University, SE-901 87 Umeå, Sweden