Heartworm Infections Increase By Almost 60%

A new Canadian study conducted in 2010 shows heartworm infection in dogs has increased by nearly 60%, a significant increase from 2002 when the last heartworm study was conducted. Dr. J. Owen Slocombe of Ontario Veterinary College at the University of Guelph led the research project.

These latest results are based on input from over 1,200 Canadian veterinary clinics. They show a total of 367,385 dogs were tested, of which 561 dogs tested positive for heartworm disease. The findings show a growing threat of heartworm in dogs in 2010 versus 2002, when only 354 dogs had contracted the potentially deadly parasite.

Why the dramatic increase?

Researchers speculate that one contributor to the rise in infections may be the increase in the number of dogs brought into Canada. These so-called "Katrina dogs" - those "rescued dogs' adopted from southern US states where heartworm infections are prevalent - can spread the disease to their Canadian counterparts.

Heartworm most prevalent in three provinces

Heartworm infections in Canada continue to be concentrated in southern Ontario, southern Manitoba and southern Quebec.

Click on the left-hand links for to find out if your city had any heartworm cases.

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2010 Heartworm Cases

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Ontario Heartworm Results

Dogs from Ontario appear to have the highest risk of contracting heartworm disease, according to a recent 2010 research study led by Dr. J. Owen Slocombe of Ontario Veterinary College at the University of Guelph.

Ontario Is A Hotbed For Heartworm

In this Canada-wide study, 367,385 dogs were tested. From this number, 289,229 dogs were from Ontario, and 428 tested positive for this potential deadly parasite, a significantly higher number compared to the rest of Canada. The latest results show an increase of more than 60% in the number of Ontario dogs that tested positive for heartworm compared to the last study conducted in 2002.

2010 Heartworm Cases


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Locations of Dogs Testing Positive

Search for your city:
CityCasesVet Clinics Responding
Ancaster 5 2
Ajax 1 1
Alliston 1 1
Amherstburg 4 2
Aurora 5 2
Aylmer 6 2
Barrie 3 2
Beamsville 1 1
Belleville 3 3
Bowmanville 1 1
Bracebridge 1 1
Brampton 3 2
Brantford 24 6
Burlington 4 2
Caledonia 65 2
Cambridge 2 2
Carleton Place 2 2
Chatham 6 3
Cobourg 2 2
Cornwall 5 1
Drumbo 1 1
Dryden 2 1
Dundas 1 1
Dunnville 4 1
Durham 1 1
Elmira 1 1
Embrun 4 1
Etobicoke 4 2
Forest 3 1
Fort Erie 9 2
Fort Frances 1 1
Grirnsby 2 1
Guelph 7 4
Hagersville 6 1
Hamilton 14 6
Harriston 1 1
Ingersoll 2 2
Kemptville 1 1
Kingston 2 2
Kingsville 2 2
Kitchener 2 1
Komoka 1 1
Lanark 1 1
Leamington 4 1
London 17 9
Markham 1 1
Maxville 1 1
Milton 2 2
Mississauga 4 4
Mount Brydges 6 1
Napanee 2 1
Navan 1 1
Nepean 1 1
Niagara Falls 2 2
North Bay 1 1
Norwich 5 1
Oakville 9 4
Orangeville 3 2
Orillia 2 1
Orleans 9 3
Oshawa 2 2
Ottawa 8 6
Paris 1 1
Parry Sound 1 1
Perth 2 1
Port Colborne 2 1
Port Dover 5 1
Prescott 1 1
Richmond Hill 2 1
Rockland 1 1
Sarnia 11 4
Scarborough 1 1
Sharon 1 1
Simcoe 21 3
Smith Falls 2 1
Southampton 1 1
St. Catharines 6 4
St. Thomas 2 2
Stayner 1 1
Stoney Creek 4 2
Stratford 1 1
Strathroy 8 1
Sturgeon Falls 1 1
Thornhill 1 1
Tillsonburg 3 2
Toronto 18 10
Trenton 2 1
Unionville 1 1
Uxbridge 4 2
Vineland 1 1
Wallaceburg 12 1
Waterdown 4 2
Welland 2 1
Whitby 2 2
Windsor 3 2
Winona 3 1
Zurich 1 1
TOTAL428179

Quebec Heartworm Results

Dogs from Quebec, especially in the southern portion of the province, appear to have the second highest risk of contracting heartworm disease according to a recent 2010 research study led by Dr. J. Owen Slocombe of Ontario Veterinary College at the University of Guelph.

Quebec cases up nearly 100%

In this Canada-wide study, 367,385 dogs were tested. From this number, 48,301 dogs were from Quebec, of which 41 tested positive for this potential deadly parasite. The latest results are nearly double the number of Quebec dogs that tested positive for heartworm based on the last study conducted in 2002.

2010 Heartworm Cases


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Locations of Dogs Testing Positive

CityCasesVet Clinics Responding
Gatineau75
Beaconsfield11
Hemmingford21
Howick41
Laval21
Marieville21
Mont-Joli22
Mont-Laurier11
Montréal11
Québec11
Rawdon61
Ste-Geneviève11
Ste-Thérèse11
St-Eustache62
St-Jérôme22
Wakefield21
TOTAL4123

Manitoba Heartworm Results

Dogs from Manitoba appear to have the third highest risk of contracting heartworm disease, according to a recent 2010 research study led by Dr. J. Owen Slocombe of Ontario Veterinary College at the University of Guelph.

Manitoba cases up nearly 46%

In this Canada-wide study, 367,385 dogs were tested. From this number, 23,192 dogs were from Manitoba, of which 77 tested positive for this potential deadly parasite. The latest results show an increase of nearly 46% in the number dogs from Manitoba that tested positive for heartworm, based on the last study conducted in 2002.

2010 Heartworm Cases


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Locations of Dogs Testing Positive

CityCasesVet Clinics Responding
Anola21
Beausejour262
Minnedosa11
Oak Buff21
Oakbank51
Selkirk52
Steinbach113
Winnipeg2512
TOTAL7723

Heartworm Results for the Rest of Canada

Dogs from Western Canada (B.C., Alberta & Saskatchewan) and from Eastern Canada (New Brunswick, Nova Scotia P.E.I., Newfoundland & Labrador) appear to have the lowest risk of contracting heartworm disease, according to a recent 2010 research study led by Dr. J. Owen Slocombe of Ontario Veterinary College at the University of Guelph.

15 cases reported

In this Canada-wide study, 367,385 dogs were tested. From this number, 15 dogs from Western Canada (excluding Manitoba) and the Maritime provinces tested positive for this potential deadly parasite. While the number doesn't seem alarming compared to other provinces, the number of reported cases has increased since the last study, which took place in 2002.

2010 Heartworm Cases

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Locations of Dogs Testing Positive
CityCasesVet Clinics Responding
British Columbia
Kamloops42
Delta11
North Vancouver22
Richmond11
TOTAL86
Alberta
Calgary11
Tofield11
TOTAL22
Saskatchewan
Indian Head11
Regina11
TOTAL22
Maritimes
Bathurst11
Saint John11
Bedford11
TOTAL33

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