[1] Niger Delta Univ, Dept Internal Med, Niger Delta Univ Teaching Hosp, Yenagoa, Bayelsa State, Nigeria
[2] African Field Epidemiol Network, Abuja, Nigeria
[3] Niger Delta Univ, Dept Community Med, Niger Delta Univ Teaching Hosp, Yenagoa, Bayelsa State, Nigeria
[4] Delta State Univ, Fac Clin Med, Dept Internal Med, Abraka, Delta State, Nigeria
[5] Univ Abuja, Dept Internal Med, Teaching Hosp, Gwagwalada, Nigeria
[6] Univ Nigeria, Dept Med, Teaching Hosp, Ituku Ozalla, Enugu, Nigeria
[7] Univ Maiduguri, Univ Maiduguri Teaching Hosp, Maiduguri, Borno State, Nigeria
[8] Fed Med Ctr Yenagoa, Dept Community Med, Yenagoa, Bayelsa State, Nigeria
[9] Univ Ibadan, Dept Med, Univ Coll Hosp, Ibadan, Oyo State, Nigeria
[10] Bayero Univ Kano, Coll Hlth Sci, Dept Med, Infect Dis & Trop Med Unit, Kano, Nigeria
[11] Infect Dis Hosp, Kano, Nigeria
[12] Univ Port Harcourt, Dept Internal Med, Coll Hlth Sci, Port Harcourt, Nigeria
[13] Fed Med Ctr, Dept Internal Med, Yola, Adamawa State, Nigeria
[14] Zamfara State Minist Hlth, Zamfara, Nigeria
[15] Usmanu Danfodiyo Univ Sokoto, Dept Med Microbiol & Parasitol, Sokoto, Nigeria
[16] Fed Med Ctr Abeokuta, Dept Med, Abeokuta, Ogun State, Nigeria
[17] Irrua Specialist Teaching Hosp, Inst Lassa Fever Res & Control, Irrua, Nigeria
[18] Irrua Specialist Teaching Hosp, Dept Obstet & Gynaecol, Irrua, Nigeria
[19] Irrua Specialist Teaching Hosp, Dept Community Hlth, Irrua, Nigeria
[20] Irrua Specialist Teaching Hosp, Dept Internal Med, Irrua, Nigeria
[21] Ibrahim Badamasi Babangida Specialist Hosp, Dept Med, Minna, Niger State, Nigeria
[22] Fed Med Ctr Birnin Kebbi, Dept Paediat, Birnin Kebbi, Kebbi State, Nigeria
[23] Abubakar Tafawa Balewa Univ, Dept Med, Teaching Hosp Bauchi, Bauchi, Nigeria