While head lice have been traditionally considered a primary school problem, they are now moving over to secondary school pupils scalps, according to new research.

The public health institute RIVM has been carrying out a volunteer project to monitor the spread of head lice and found that while 28% of primary school children in its survey had lice, 19% of secondary school pupils had them as well.

‘I think the reason is the behavour of secondary school pupils,’ RIVM lice expert Desiree Beaujan told RTL news. ‘There is a lot of hugging. And when they take selfies, youngsters’ hair touches, which can transfer the lice.’

The RIVM is now going to change its anti-lice campaigns to include teenagers. ‘Parents need to know there are lice at secondary schools because there are no nit parents there,’ she said. Dutch primary schools regularly bring in parents to check the heads of children and queen Maxima has also served as a nit mother.

The RIVM survey also found that three quarters of nit infestations were on the heads of girls. This may be due to their long hair, the RIVM said.

One in 10 adults in the survey of 2,000 volunteers also had head lice.