Two children at a primary school dealing with an infection outbreak have died, health authorities have confirmed.

Both children were pupils at Millstead Primary School in Everton, Liverpool, which teaches children aged two to 11 years, who have special educational needs.

But the UK Health Security Agency (UKHSA) said a link between their deaths has not been established but both are “unlikely” to be due to a “number of cases” of an infection called Giardia.

The agency has not confirmed the sex or ages of the children who have died. They were reportedly aged five and six.

Giardiasis is an infection of the digestive system caused by tiny parasites known as Giardia lamblia, the UKHSA said.

The infection can cause symptoms such as diarrhoea, stomach cramps, flatulence and bloating but it is generally not a serious risk to health and can be treated easily with antibiotics, the agency said.

Emma Savage, consultant in health protection for the Cheshire and Merseyside Health Protection Team, said: “UK Health Security Agency are aware of the sad deaths of two children who attend Millstead Primary School and our thoughts are with the family, friends and school community.

“The deaths are unlikely to be due to Giardia. Giardia usually causes a self-limiting gastrointestinal illness which can spread easily in households and school settings.

“Investigations are ongoing, and we have provided information and advice to the school and parents. Public health measures have been put in place to help prevent further cases.”

The agency has not said when either child died but a letter from the school’s headteacher was sent on May 21, alerting parents to two cases of Giardiasis confirmed at the school.

Millstead School head, Michelle Beard, said: “The entire Millstead School community is devastated to have learned of the sad recent passing of two of our younger children.

“We have sent our sincerest condolences to both of their families.

“Both children filled their classes with joy during their time with us, and they will forever be in our hearts.

“We are working closely with our families, staff and pupils to support them as we come to terms with this terribly sad news.”

The UKHSA advises that once treated with antibiotics, symptoms should stop in about a week, but can sometimes last longer.

Giardiasis can be spread by direct contact with infected people or animals, or from swallowing contaminated water, food or drinks.

Multiple studies suggest Giardiasis is associated with travel and more prevalent in developing nations, but can also be locally acquired.

A 2018 study published by Cambridge University Press said regions of the world where giardiasis thrives tend to be in those with poor living conditions, including malnourishment, squalor and unsanitary conditions which promote spread of the disease.

Giardiasis can be prevented by washing your hands with soap and water and after going to the toilet or changing nappies and before handling or eating food.

Any parents concerned that they or their child is displaying symptoms related to Giardia, should contact their GP or NHS 111.

Further information is available on the NHS webpage: www.nhs.uk/conditions/giardiasis/