A woman has been arrested on suspicion of child neglect after the unexplained death of an eight-year-old girl in Lampeter.
Dyfed-Powys Police are investigating circumstances of the girl's death at Maes-y-Deri in the town on the evening of 22 December.
The police have confirmed that a 33-year-old woman has been released as inquiries continue into the "sudden death" of the girl.
Meanwhile Public Health Wales said on Wednesday that it was looking into possible links to a rare complication of Strep A infections.
It said it was working with Hywel Dda University Health Board and Ceredigion Ceredigion Council following the death of a child in Lampeter.
Dr Graham Brown, consultant in communicable disease control for Public Health Wales, said: "We offer our deepest condolences to the family, friends and all those affected.
"Public Health Wales cannot comment on individual cases.
"We are investigating links to Invasive Group A Streptococcal disease (iGAS), a very rare complication of Group A Streptococcal infection."
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