[1] Univ Republica, Fac Med, Inst Higiene, Dept Bacteriol & Virol, Montevideo, Uruguay
[2] Univ Republica, Fac Med, Ctr Hosp Pereira Rossell, Dept Pediat, Montevideo, Uruguay
[3] Univ Republica, Fac Med, Hosp Clin Dr Manuel Quintela, Dept Farmacol & Terapeut, Montevideo, Uruguay
[4] Minist Salud Publ, Hosp Pereira Rossell, Cent Lab, Montevideo, Uruguay