When we talk about parasite prevention, we mean prevention against fleas, ticks and other intestinal parasites. These include heartworm, tapeworm, hookworm and roundworm.
Treatment can include annual injection, tablets and chews and spot on applications.
As with vaccinations, prevention is far more preferable to treatment.
Animals which become infested with fleas for example, can suffer allergies to the bites. They can also cause wider issues such as excessive scratching which can in turn cause wounds and nasty skin conditions.