An investigation has been launched into an outbreak of hepatitis A at a primary school in Gelligaer.
Four cases have been found at Glyn Gaer Primary School, with staff and pupils offered vaccinations as a precaution.
Public Health Wales, Aneurin Bevan University Health Board and Caerphilly Council Borough Council, are conducting the investigation into the cause of the outbreak.
Heather Lewis, Consultant in Health Protection for Public Health Wales, said: “Hepatitis A is a viral infection, usually short lived that has unpleasant symptoms but is rarely serious. Children often only have a very mild illness.
“Symptoms can include flu-like symptoms such as tiredness, general aches and pains, headaches and fever, as well as loss of appetite, nausea or vomiting, abdominal pains, jaundice, very dark urine and itchy skin.
“Good hand washing after using the toilet and before preparing or eating food is the best way to prevent the virus spreading.
“Children may have very few symptoms but can pass the virus onto others so we are reminding parents to encourage good hand washing at all times.
“Parents are also being advised not to send their child to school for seven days if hepatitis A is suspected.
“We are confident that to date, all the public health actions needed to control this outbreak have been taken and that the risk to the public remains low. However, due to the very long incubation period of hepatitis A we may see more cases in individuals who were exposed before they were vaccinated.
“We continue to work closely with Environmental Health Officers to investigate this outbreak and to offer advice to parents, school staff and pupils.
“People are advised to contact their own GP or NHS Direct Wales on 0845 46 47 if they have any concerns about their health or their child’s health.”
The hepatitis A vaccination is not routinely offered on the NHS as the infection is classified as rare in the UK, with only 13 reported cases in Wales in 2012.