Will Falconer, DVM Moderator
Thanks Elle, but there's quite a bit more on both to control these beasts and keep your Vital Animal free from hitchhikers.
On my Non-Toxic Flea Control page, it's actually the intent that the majority of the efforts be directed at the eggs and larva, 80% of the population of the fleas at any given time. Absent this, you'll be spending a lot of time picking off adults.
As to natural heartworm prevention, my book Vital Animals Don't Get Heartworms lays out a holistic approach to making your animal bullet proof against developing these worms. If you merely test yearly without applying the rest of the principals of sound natural prevention you'll likely find a positive test at some point, indicating worms have lodged in your animal's heart. Treatment then is complicated, expensive, and toxic. Far better to thoroughly arm your animal with the tools of resistance outlined in this 50 page book.