[1] Univ Gondar, Inst Publ Hlth, Coll Med & Hlth Sci, Dept Publ Hlth, Addis Ababa, Ethiopia
[2] Univ Gondar, Coll Med & Hlth Sci, Dept Med Microbiol, Gondar, Ethiopia
[3] Univ Leipzig, Inst Clin Immunol, Fac Med, D-04103 Leipzig, Germany
[4] Univ Gondar, Inst Publ Hlth, Coll Med & Hlth Sci, Dept Epidemiol & Biostat, Gondar, Ethiopia
[5] Addis Continental Inst Publ Hlth, POB 196, Addis Ababa, Ethiopia