PREGNANT women in Scotland are being urged to protect their unborn babies from whooping cough as cases of the illness rise 81 per cent.

The number of people being diagnosed with the problem has suddenly increased north of the border - with the number of infants falling ill so far this year almost double the figure for the whole of 2015.

Whooping cough can be fatal for the very young and so far this year 19 babies aged just two months or less have come down with the infection in Scotland.

Experts at Health Protection Scotland are advising pregnant women to take up the offer of a whooping cough vaccine so their child will be immunised when they are born.

Dr Claire Cameron, strategic lead for immunisation at Health Protection Scotland, said: "Whooping cough can be a very serious disease indeed for young infants, with bouts of coughing and gasping for breath. You can have complications like pneumonia, breathing difficulties and even brain damage from it."

Whooping cough was once a common childhood illness but it is now included in the routine vaccinations children receive from the age of eight weeks. However, in 2012 there was an outbreak across the UK and further afield with cases soaring across all age groups. In Scotland microbiology labs confirmed 1,926 cases that year. That autumn, experts recommended pregnant women receive vaccination from the illness to help protect their babies until they were old enough to have the injection themselves.

Since then levels of whooping cough in the under ones have tumbled from 140 in 2012 to 19 the following year and 20 in 2014.

However, while diagnoses remained stable for the first part of 2015, there has been a surge in more recent months. So far 38 babies under the age of one have been treated for the condition this year.

By the beginning of November a total of 778 cases had been confirmed across all ages in Scotland, compared to 430 for the same period in 2014, an increase of 81 per cent.

The reasons for the 2012 outbreak and the current surge are not fully understood, but it is known that the immunity provided by the whooping cough vaccine wanes with age.

Dr Cameron said: "The reason for the (outbreak) is still under investigation. Is it something to do with everyone being vaccinated so their immune system isn't being pepped-up by being exposed to the bacteria in the community? Is it because the bacteria has changed in some way?"

The illness is highly contagious. It causes intense bouts of coughing which can be followed by a gasp for breath, creating the eponymous whoop sound. It passes from person to person in the droplets people expel when they sneeze and choke.

Dr Cameron said while whooping cough - which is also known as pertussis - could be unpleasant for adults their key concern was infants. While death rates in Scotland have not been released, she said Public Health England had reported 12 deaths among young babies since the vaccine was introduced.

"Eleven of those babies were born to mothers who had not been vaccinated against pertussis," said Dr Cameron. "We know that the vaccination is very effective."

She added that a study by the Medicines & Healthcare products

Regulatory Agency had shown there were "no safety concerns associated with pertussis vaccination in pregnancy."

The latest figures show 61 per cent of pregnant women in Scotland receiving the pertussis vaccine. Dr Cameron said: "There are increased levels of disease and we are making people aware of that and encouraging them to be vaccinated."