[1] Univ Coll Hosp, Dept Family Med, 1 Queen Elizabeth Rd, Ibadan 200212, Nigeria
[2] Univ Ibadan, Coll Med, Dept Virol, Ibadan, Nigeria
[3] Univ Ibadan, Coll Med, Dept Clin Pharmacol & Therapeut, Ibadan, Nigeria
[4] Univ Ibadan, Coll Med, Dept Med Microbiol & Parasitol, Ibadan, Nigeria
[5] Univ Ibadan, Coll Med, Dept Med, Ibadan, Nigeria
[6] Northwestern Univ, Feinberg Sch Med, Div Infect Dis, Chicago, IL 60611 USA