Health officials are raising the alarm over an outbreak of whooping cough in southern Alberta.

Vivien Suttorp, Alberta Health Services' lead medical officer of health for the south zone, says there have been 12 reported cases in the past week in an area from Fort Macleod to Coaldale, which forms a sort of horseshoe around Lethbridge.

"I think in southern Alberta we have a higher rate of whooping cough, just random cases, throughout the last three years," she said. "What's unique about the last week is we've had a sudden significant increase."

Whooping cough, or pertussis, is a bacterial infection that causes severe coughing fits. The infection can remain for weeks.

Rates of whooping cough are highest in southern Alberta with more than 50 cases in 2016, and 53 cases in 2015.

Children at particular risk

AHS warns infants one year of age and under are at greatest risk of complications, including pneumonia, convulsions, brain damage and even death.

In 2012, a four-week-old baby died from the disease in southern Alberta.

"Given the large number of un-immunized individuals who live in this area, and children especially, we're quite concerned that this is going to be a prolonged outbreak and obviously with some morbidity, so individuals and especially kids that can get quite sick," said Suttorp.

She says it's important for children and adults to ensure they're vaccinated. The Fort Macleod area ranks nearly dead last out of 132 local health zones in Alberta for immunization rates for a broad range of diseases.

"There is treatment for individuals who have whooping cough and it's best to have treatment early on, there's antibiotics for people who are sick to also just minimize that spread of the disease," said Suttorp.