Flea Control

Yuck, fleas!

Lots of insects are beneficial for the environment.  We need bees to pollinate our crops and Lady Bugs to feast on predatory spider mites.  However, we just can’t think of anything good about fleas.  Fleas can cause allergic skin disease in our dogs and cats and carry infectious disease.  It was the rat flea (Xenopsylla cheopis) which carried plague around the world in the Middle Ages.

Fortunately, our patients are usually only troubled by the “cat flea”, Ctenocephalides felis, which is a bit misnamed since it loves dogs, cats, raccoons, possums, foxes, coyotes, as well as other wildlife.  This flea doesn’t carry plague but does transmit tapeworms, bartonella, and rickettsial diseases to our patients.

Fleas enjoy the Pacific NW due to the year-round temperate climate, especially now that most of our pets spend most of their time inside our temperature-controlled homes.  Before better flea control options became available in the 1990’s, a lot of our patients could look like these pictures.

Fleas as insects have a life cycle like the butterfly, though not as pretty.  They feed on the pet, laying eggs that drop onto the bedding or floor, which then hatch to larvae, pupate, and then emerge as “beautiful” adult fleas.  The lifecycle can be as fast as 3 weeks but fleas can “slow” themselves down in cooler weather to take as long as 5 months to pupate.  Female fleas lay 40-50 eggs on your pets each day.  They can lay 20,000 eggs in their life.

OK, they are disgusting but what can we do?

The first thing to know is that fleas are a neighborhood problem.  Some neighborhoods can have a larger number of fleas based on housing and animal density, along with the number of wildlife reservoirs.  Other neighborhoods may have lower flea counts.  But whatever the flea burden, the most important thing we can do is use targeted flea products and treat year round.  Animals who are bitten by fleas but are allergic often don’t have any fleas on them since they “destroy the evidence” by eating it.

Flea products fall into two main categories, topical and oral medications.  Most topicals don’t need a prescription, oral products do. Oral products fall into two drug classes:  spinosad class or isoxazoline class.  Because fleas are big business, there are other products out there as well that you can find here.

Topicals Oral Spinosad Oral Isoxazoline
  • Spinetoram (Cheristan, OTC)
  • Indoxacarb (Activyl OTC)
  • Comfortis
  • Trifexis
  • Nexgard
  • Bravecto (Topical for cats)

For dogs, we carry a few flea products, including the spinosad product (Trifexis) that covers fleas and heartworm, along with Nexgard which covers fleas and ticks.  Each product has pros and cons.  Spinosad products are generally safe but can’t be used in dogs being treated for demodex (Puppy mange).  Isoxazolines are generally safe but may not be used in dogs with a seizure history.  We reviewed all of the products and chose Nexgard since it’s safe in puppies and has the longest time on the market with a good window to assess for post-approval adverse effects.  We also carry Activyl as a monthly topical product that kills fleas and ticks.

For cats, we carry the isoxazoline product Bravecto which is a topical prescription medication giving up to 3 months of protection.  This product is generally safe; however, should not be used in pets with a history of seizure.  The other flea product we carry is Cheristin, a topical spinetoram medication.  Topical products for cats are easier to administer than oral medications.  They are less stressful for you and your cats and give you peace of mind knowing your cat received the full dose.

We know that there is some resistance to some of the topical products (Fipronil being the worst) but many times when a flea product looks to be failing there may be gaps in full control.

Really good flea control requires four avenues of attack.

  1. Treat all the pets in the household (Pets may appear to get “worse” in the first 30-50 days as baby fleas hatch out of eggs and pupae since these are nearly impossible to kill).
  2. Remove flea eggs, larvae, and pupae from the household.  Usually mechanical removal (Vacuuming and bedding wash) is sufficient but if there is carpet, premise spray may be necessary.  Look for products that list both an adulticide and insect growth regulator (IGR).  You need to do use to break the flea life cycle.  We do not recommend fogger type treatments.  They go up, then come down and don’t go underneath furniture where most fleas and larvae hide.
  3. Consider outside sources:  if there are wandering cats or wildlife who frequent the yard, consider a yard premise spray (Imidicloprid sprays such as Advantage Yard and Premise spray works reasonably well).
  4. Gaps in treatment will lead to reinfestation.