Parasite prevention for dogs: a topic that is often confusing, because there is more than one parasite. Fleas, ticks, leishmania, and heartworm are four different problems, each requiring different solutions. Understanding the differences is the first step toward choosing the right prophylaxis.
The four main enemies
Fleas
Insects that live on the dog's skin. They cause itching, allergic dermatitis (FAD — Flea Allergy Dermatitis), and transmit tapeworms. Just one flea in the house can lay up to 50 eggs a day.
Risk season: all year round indoors with heating, peak in spring-summer-fall.
Ticks
Arachnids that attach and suck blood for days. Dangerous because they transmit pyroplasmosis (babesiosis), Lyme disease, ehrlichiosis, rickettsiosis. Some diseases can be fatal.
Risk season: March-November, but with climate changes, increasingly even in winter.
Leishmania
A protozoan transmitted by the bite of the phlebotomine (a small sandfly, similar to a mosquito). It is a severe chronic disease for dogs, widespread in central-southern Italy, along the coast and in the Po Valley.
Risk season: April-October, evening-night activity.
Heartworm
A parasitic worm of the heart and lungs, transmitted by mosquitoes. It can be fatal if not treated. Mandatory prevention in the Po Valley, Adriatic coast, and certain areas of Tuscany and the south.
Risk season: April-November.
The three forms of antiparasitics
Spot-on (pipettes)
A liquid applied between the shoulder blades. The active ingredient spreads over the skin and fur.
Pros:
- Easy to administer
- Covers fleas and ticks, some also target sandflies
- Available in weight-specific doses
Cons:
- Must be applied every 4 weeks
- Effectiveness diminishes with frequent baths or swims
- Some dogs may have skin reactions
Collars
Gradually release the active ingredient for 6-8 months.
Pros:
- Long-lasting (a collar covers a good part of the season)
- Protection against fleas, ticks, and phlebotomines (some)
- Water-resistant
Cons:
- Can cause reactions at the contact site
- Dangerous if the dog chews on them (family dog or another dog)
- Must be adjusted tightly around the neck
Pills (oral)
To be administered every 1 or 3 months depending on the product.
Pros:
- Maximum effectiveness, systemic distribution
- Not washed away, independent of baths
- Covers fleas and ticks
- Some include intestinal endoparasites
Cons:
- Higher cost
- Do not cover leishmania or heartworm — must be combined with other prophylactics
- Need to hide the pill well for picky dogs
Which to choose: the typical combination
City dog, house with garden, low infestation area:
- Monthly pill for fleas and ticks
- Monthly pill or injection for heartworm (April-November)
Dog in endemic area for leishmania (central-southern Italy, coastal, plain):
- Collar with specific phlebotomine repellent (e.g., with deltamethrin)
- Pill for fleas/ticks if needed
- Leishmania vaccine to be discussed with the veterinarian
- Heartworm prophylaxis
Dog that goes on many hikes, in forests, on trails:
- Combination of spot-on + spray (ticks)
- Heartworm + leishmania depending on the area
Frequent mistakes
- Starting prophylaxis late — heartworm should be prevented all year round or at least from April, it is not easy to treat once contracted.
- Stopping too early — ticks are now present even in December.
- Using dog products on cats — some active ingredients (permethrin) are fatal for cats.
- Combining different antiparasitics without asking — some combinations are dangerous.
- Relying only on the collar in a phlebotomine area — the indicated duration is often shorter than reality.
When to see the veterinarian
- Before starting annual prophylaxis: check-up visit, heartworm test (blood), leishmania and Ehrlichia tests in endemic areas
- After removing a tick that has been attached for more than 24 hours
- If you see a resurgence of fleas despite using antiparasitics
- If the dog has an allergic reaction to the product
Things to keep in mind
There is no single antiparasitic that does it all. Dog protection is built up in layers, based on the area, lifestyle, and season. An annual visit to the veterinarian to define the plan is the simplest — and least expensive — way to avoid serious diseases.
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