Strep A links investigated after child's death in Powys
Links with the invasive group A streptococcal disease (iGAS) are being investigated after the death of a child in Powys, health experts have said.
Public Health Wales is working with local health officials and the council following a possible link to a "very rare complication" of the disease.
PHW's Dr Ardiana Gjini said people "identified for public health action have already been contacted".
"We remind parents to be vigilant for signs and symptoms," she said.
Most often, symptoms are mild - a sore throat or a skin infection that can be easily treated with antibiotics.
But strep A can cause a range of symptoms and one is scarlet fever, which mostly affects young children and, again, needs antibiotics.
Very rarely, strep A can also cause invasive group A streptococcal infection or iGAS which happens when the bacteria gets past the body's immune defences.
NHS Wales' 111 phone service took more than 18,000 calls on the weekend - more than double that of the same period last year - amid concern about strep A symptoms.
re have been 15 confirmed deaths of children with strep A since September, including Hanna Roap, seven, from Penarth, Vale of Glamorgan.
Her father, Hasan Roap, 37, has previously told BBC Wales how his family had been "traumatised" and "devastated" by her death within 24 hours of being taken ill.
Dr Gjini, a consultant in communicable disease control, said: "While we understand that parents are likely to be worried, cases of invasive group A streptococcal infection (iGAS) remain rare in Wales, and children have a very low risk of contracting the disease."
PHW has made a symptom checker for parents with a traffic light system to help them decide when to get medical help.
Referring to the child's death in Powys, Dr Gjini said: "We offer our deepest condolences to the family, friends and all those affected.  
"A multi-agency incident management team is following normal processes, and investigating links to invasive group A streptococcal disease (iGAS), a very rare complication of group A streptococcal infection.
"People identified for public health action have already been contacted and provided with appropriate treatment and advice.
"Individuals who have not been contacted do not need to take any specific action.
"However we remind parents to be vigilant for signs and symptoms of scarlet fever and iGAS."