Lung worm can initially present as a cough, but have far more reaching side effects that it's initial symptoms. Lung worm in dogs is caught by eating slugs or snails, licking the trails of slugs or snails, or eating infected fecal matter.
In cats lung worm can be caught by consuming whole birds or rats which are infected.
Lung worm grows in the intestinal tract and migrates to the lungs, where they are often coughed up and re-ingested. Respiratory tract infections ensue often followed with or accompanied by pneumonia - current recomendations are long term antibiotics. (Merck, 2011)
Opposed to recent veterinary implications lung worm cannot be caught by ingestion of human grade meat obtained from a butcher with no lungs or intestines attached.
Merck (2011) (Internet) Available from: http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/120700.htm (accessed 02/10/2011)