Monthly Simparica Trio prevents heartworm disease, kills adult fleas and is indicated for the treatment and prevention of flea infestations, the treatment and control of tick infestations, and the treatment and control of roundworm and hookworm infections in dogs and puppies 8 weeks of age and older, and weighing 1.3kg or greater. Simparica Trio blocks the pathogen that may cause Lyme disease by killing deer ticks.