[1] CAIRO UNIV,FAC MED,DEPT TROP MED,CAIRO,EGYPT
[2] CAIRO UNIV,FAC MED,DEPT CLIN PATHOL,CAIRO,EGYPT
[3] CAIRO UNIV,FAC MED,DEPT PEDIAT,CAIRO,EGYPT
[4] JOHNS HOPKINS UNIV,SCH MED,DIV INFECT DIS,BALTIMORE,MD 21205
[5] UNIV MARYLAND,SCH MED,DEPT EPIDEMIOL & PREVENT MED,BALTIMORE,MD
[6] UNIV MARYLAND,SCH MED,INT HLTH PROGRAM,BALTIMORE,MD