Are there areas where these infections are more common?
Eucoleus aerophilus seems to be found wherever there are dogs or cats. The prevalence of Eucoleus boehmi is not well known, but it seems to be worldwide in distribution. Filaroides hirthi occurs sporadically, and periodically appears in some kennels or in individual dogs. Oslerus osleri tends to occur sporadically and in certain regions. According to a study conducted in 2012, it is a relatively common parasite of coyotes in Nova Scotia. Crenostoma vulpis is widely distributed around the world in the fox population and consequently, in dogs that share the same environment. In Canada, it has spread from Atlantic Canada into other provinces including Quebec and Ontario.
What causes lungworm infection?
A lungworm infection is caused by one of several parasitic roundworms. In North America, the parasitic lungworms that infect dogs are Eucoleus aerophilus (formally known as Capillaria aerophilus), Oslerus osleri (formally called Filaroides osleri), Crenostoma vulpis (fox lungworm), Eucoleus boehmi and Filaroides hirthi. Angiostrongylus vasorum (French heartworm) may also be considered a lungworm due to the lung damage it causes. It is an emerging parasite in North America, currently only seen in the Atlantic provinces of Canada and the eastern U.S.
Eucoleus aerophilus is primarily known as a parasite of foxes but it has also been found in dogs, cats and other carnivores. The others are parasites that infect dogs and other related members of the canid family.
The adult worms of Eucoleus boehmi live in the nasal cavity of dogs and related canids. Adult worms of Oslerus osleri and Crenostoma vulpis live in the trachea and bronchi. Filaroides hirthi adults live in the lungs. Angiostrongylus vasorum live in the arteries of the lungs.