There have been more than 100 cases of whooping cough reported in New Brunswick. (Stock)

A whooping cough outbreak is continuing to worsen as cases of the illness doubled in the last month, according to New Brunswick’s public health office.

Dr. Eilish Cleary, the province’s chief medical officer of health, said there are now more than 100 reported cases of whooping cough – or pertussis – an increase of 53 cases since the end of February.

"We are still experiencing a significant whooping cough outbreak in New Brunswick," Cleary said.

The cases are primarily in the southern and eastern areas of the province.

"Public Health officials are monitoring the situation closely to ensure that appropriate interventions are in place," she said.

The public health office is reporting the outbreak is most common in children between the ages of five and 14, and in children less than a year old.

The number of children diagnosed with whooping cough is well above recent levels. In January 2011, there were 14 cases of whooping cough in the Moncton area.

In 2009, there were a total of 15 cases province-wide.

Whooping cough is a disease of the lining of the respiratory tract that is caused by the Bordetella Pertussis bacterium.

It begins with cold-like symptoms including sneezing, runny nose, low-grade fever and mild cough and worsens over a period of several weeks to include serious coughing spells that often end with a "whoop," Cleary said in a recent statement.

Whooping cough is easily transmitted from person to person, mainly through droplets from the nose, mouth and throat of an infected person.

The public health department recommends immunization as the best way to avoid whooping cough.