Alberta Health Services has declared an outbreak of whooping cough, or pertussis, across the western part of southern Alberta. The area includes the county of Lethbridge, Coaldale and Fort Macleod.

So far this year, there have been 17 confirmed cases in the south zone, 12 in the last week alone, according to Alberta Health Services. The most recent 12 cases are believed to be linked.

“This outbreak is in the same area where we are seeing outbreaks of vaccine preventable diseases on a regular basis,” said Dr. Vivien Suttorp, a medical officer of health for AHS South Zone.

Suttorp says within Southern Alberta there are a number of small community pockets that have very low immunization rates and as a result children in these communities have become more susceptible to disease.

“Immunization rates here are so low that children are not benefitting from herd immunity.”

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Suttorp says these communities experienced an outbreak of whooping cough back in 2009 as well as a measles outbreak in 2013.

“We know generally there are three reasons why people avoid vaccines. Complacency – they believe vaccines just aren’t important, the second reason is an access issue and the third reason is trust, either a mistrust of vaccines or vaccine providers.”

READ MORE: Parents in Calgary zone schools warned of potential whooping cough risk

Last week, health officials in the Calgary zone issued a similar warning about whooping cough after eight cases were diagnosed in the Okotoks area. The cases were all believed to be linked to two families, however an official outbreak has not been declared in the Calgary zone.

WATCH: Parents in the Okotoks area are being asked to take precautions after a cluster of whooping cough cases were recently diagnosed. Bindu Suri filed this report on June 1, 2017.

1:50 Parents in Calgary Zone schools warned of potential whooping cough risk Parents in Calgary Zone schools warned of potential whooping cough risk

Whooping cough is a highly contagious bacterial infection which can be very serious for young children. In infants, the illness can be fatal. In 2012, a southern Alberta infant died from complications of whooping cough. Harper Whitehead was just a month old and too young to be vaccinated against the disease. Whooping cough can be treated with antibiotics but Dr. Suttorp warns that to be effective, antibiotics must be administered early in the course of the disease.

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According to AHS, immunization is the best protection against whooping cough. The vaccine is part of Alberta’s routine childhood immunization schedule.

Doses of the dTAP vaccine — which delivers protection against diptheria, whooping cough, tetanus and polio — are recommended for all children at age two months, four months, six months, 18 months, between four and six years and again in grade nine.

READ MORE: Anti-vax mother warns others of daughter’s whooping cough ‘nightmare’

Adults are urged to get a booster at some point and its recommended pregnant women get the vaccine during their third trimester of pregnancy. The vaccine are covered by Alberta Health and can be accessed through community health centres or public health offices.

READ MORE: Why do parents refuse vaccines? They don’t think they’re necessary anymore: study

Symptoms of whooping cough are initially similar to a cold and include runny nose, sneezing, fever and a mild cough. The cough progresses over the course of about a week to something more severe and can be followed with what sounds like a ‘whooping’ noise when inhaling. The cough may last for two months or more. Vomiting after a coughing spell is also common.

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Anyone who suspects they or a family member may be sick with whooping cough should stay at home and call health link at 811 before seeking medical care. Whooping cough is typically treated with antibiotics.

READ MORE: Canada seeing outbreaks of whooping cough. Is waning immunity one reason?