Ontario map
FIGURE 1. Areas with dogs with heartworm in Ontario
+ + + +
Arnprior
Aylmer Simcoe
Barrie Ajax Drumbo Niagara Falls St. Catharines
Belle River Amherstburg Dunnville North Gower St. Clements
Bolton Ancaster Dunrobin Norwich St. George
Burlington Aurora Emeryville Oakville St. Thomas
Dryden Beamsville Essex Orangeville Stirling
Etobicoke Belleville Fonthill Orillia Stoney Creek
Exeter Blenheim Forest Orleans Stratford
Fenelon Falls Bobcaygeon Fort Erie Ottawa Strathroy
Fisherville Bracebridge Glencoe Owen Sound Sutton
Grimsby Brampton Guelph Paris Sydenham
Holland Landing Brantford Hagersville Pembroke Thunder Bay
Kingston Brights Grove Ingersoll Peterborough Tillsonburg
Kitchener Caledonia King City Pickering Toronto
Komoka Cambridge Kingsville Port Colborne Trenton
Leamington Campbellville Lakefield Port Dover Uxbridge
Listowel Cayuga Lasalle Prescott Waterdown
Manotick Chatham Lindsay Ridgetown Waterloo
Minden Cobden London Rockland Welland
Parry Sound Collingwood Midland Russell West Flamborough
Rockwood Cornwall Mississauga Sarnia Wheatley
Tecumseh Delhi Mt. Brydges Scarborough Whitby
Thornhill Dorchester Napanee Schomberg Windsor
Watford Dresden Nepean Shedden Woodstock
Areas with dogs which had been outside of Canada and presumed infected before returning or with dogs whose movements were unknown.

+Areas with dogs some of which had never left.