1. Department of Internal Medicine, Faculty of Medicine, Universitas Prima Indonesia, Medan, Indonesia; School of Medicine, Universitas Sumatera Utara, Medan, Indonesia.
2. Department of Pharmacology and Therapeutics, School of Medicine, Universitas Sumatera Utara, Medan, Indonesia.
3. Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Medan, Indonesia.
4. Department of Microbiology, School of Medicine, Universitas Sumatera Utara, H. Adam Malik General Hospital, Medan, Indonesia.