There is currently a whooping cough epidemic in Europe, with 10 times as many cases compared to the previous two years.

While an outbreak has not been declared nationwide in Canada, whooping cough is regularly detected in the country. According to the Public Health Agency of Canada, here's what you need to know about the contagious disease.

What is whooping cough?

Also known as pertussis, whooping cough is a highly contagious infection caused by the bacteria bordetella pertussis that affects the airways and lungs. It used to be called the "100-day cough" as symptoms can last for months if left untreated.

What are symptoms?

Whooping cough causes intense coughing fits that can even lead to choking or vomiting. Coughing can be so violent, that a "whooping" sound can be heard when someone tries to catch their breath. Initial symptoms can appear seven to 10 days after infection and may include mild fever, runny nose, red watery eyes and a cough.

Whooping cough is directly spread through close contact with an infected person. The bacteria that causes it is able to live on dry objects for two to six days, although indirect spread is rarer.

How common is whooping cough?

According to the Public Health Agency of Canada (PHAC), whooping cough is a cyclical disease, meaning reported case counts vary significantly by year, averaging between 500 and 4,500 annually in Canada and 20 to 40 million cases globally. The European Centre for Disease Prevention and Control says large outbreaks occur every three to five years.

Outbreaks in Canada were declared in 2023 in ManitobaSaskatchewan and Alberta. In March, Alberta Health Services warned about a spike of cases in Okotoks, south of Calgary.

"Increased pertussis activity this year is not unexpected as it follows a period of low incidence during the years of the COVID-19 pandemic," reads an emailed response to CTVNews.ca from PHAC.

How dangerous is it?

Without treatment, whooping cough can lead to brain damage and even death. It is most dangerous for children under the age of one, particularly those who are not fully vaccinated, as well as older adults. Europe has recorded 11 infant deaths and eight among older people in its ongoing outbreak. There are an estimated 400,000 deaths worldwide each year, mainly among non-immunized children in developing countries..

Is there a vaccine?

Yes. Children in Canada typically start receiving the whooping cough vaccine at two months of age. Children under six years old need five doses for full protection.

The Public Health Agency of Canada urges anyone in regular contact with a baby to be immunized at least two weeks before seeing them. The vaccine's effectiveness fades over time, so a booster dose may be needed. Booster doses are also typically given during pregnancy between 27 and 32 weeks.

Vaccination rates vary widely across the country. In the Alberta Health Services' south zone, for example, only 58.1 per cent of children under the age of two are protected. Overall, data from 2019 shows 78 per cent of children under the age of two were vaccinated in Canada.

"So with many of these infection and diseases, we need community vaccine rates to be well over 80 per cent, and for some of them, including whooping cough, ideally over 90 per cent," Dr. Craig Jenne, a professor in the department of microbiology, immunology and infectious diseases at the University of Calgary recently told CTV News Calgary.

How is whooping cough tested and treated?

Whooping cough can be detected through a lab test. All cases must be reported to local health authorities. Infections are usually treated with antibiotics.

With files from The Associated Press