of the 13,504 positive cases that were eligible for follow-up, 11,278 (83.5%) were reached and asked to provide details of their recent contacts
o blith y 13,504 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 11,278 (83.5%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar