[1] Shinyanga Referral Reg Hosp, POB 17, Shinyanga, Tanzania
[2] Catholic Univ Hlth & Allied Sci, Dept Obstet & Gynecol, POB 1464, Mwanza, Tanzania
[3] Catholic Univ Hlth & Allied Sci, Dept Microbiol & Immunol, POB 1464, Mwanza, Tanzania
[4] Muhimbili Univ Hlth & Allied Sci, Dept Microbiol & Immunol, POB 65001, Dar Es Salaam, Tanzania
[5] Catholic Univ Hlth & Allied Sci, Weill Bugando Sch Med, Dept Microbiol & Immunol, POB 1464, Mwanza, Tanzania