Gazette Vet: Fleas


By John Andersen, DVM

Many people don’t realize, but we are just now getting into the very worst time of year for fleas.  Every year, from September through October, I see cases of dogs and cats loaded with fleas every single day.

“Not me,” you might think. “I keep my house clean, we mow our grass, we have hardwood floors…”

Every day, I see really nice, clean, neat people who bring their pets in with fleas.  Interestingly, more than half the time the people are bringing in the dog or cat because it is itchy, not because they have seen the fleas themselves. When I quickly find fleas, they are surprised and sometimes a little embarrassed—“How did I not know?”

Let’s start with that question: how can you tell if your pet has fleas?

One common statement I hear is, “well, fleas always bite me and I haven’t had any bites so I know she can’t have fleas.”  The truth is that fleas definitely prefer your pets over you. Usually the only time humans are sustaining flea bites is when you have a really bad infestation, i.e., a lot of eggs hatching inside your home.

I think another reason people can miss the fleas on their pet is that our exam rooms have really bright lighting, obnoxiously bright. I do a lot of housecalls as part of our practice and really nobody has great lighting inside their house for seeing really small detailed things like fleas.

Last, many people are just not familiar with the right place to look. Interestingly in dogs, fleas are almost always found on their “rump,” just above their tail on their back. Whenever I see an itchy dog, this is the first place I start examining. I usually just comb the hair back in this area and many times will see fleas or at least flea dirt.  This is an important point.

Sometimes, there are only a few fleas. Good luck finding them on a 60-pound black dog. However, fleas always leave their telltale sign, “flea dirt.” Flea dirt is actually flea poop, and it looks like little black flecks of pepper in the hair near the skin.

So, dog itching? Get in some good lighting and start looking through the hair near the tail base for fleas or flea dirt. If he has hair loss in that area, or some flea dirt, he’s got fleas.

Cats are trickier. Because they are such good groomers, they often keep flea numbers down. They often get scabs around their head and neck from fleas. With cats, I still look around their rump, but also look on their belly and around their neck too.

Okay, now that we know how to find them, let’s revisit some basics about these horrible little bugs and how you can avoid an unwelcome infestation in your home.

First a few important flea facts:

Fleas live their entire adult life on a single animal. In other words, they do not hop from dog to dog. Once they find a friend to live on, they stay until they die.

One flea can lay up to 50 eggs per day! These eggs are laid on the animal, but they are “slippery” and soon fall off into the environment, i.e., the floor, your couch, your bedspread.

These eggs develop into tiny larvae, which develop into pupae, a little cocoon of sorts. This is all very small, almost microscopic. The spaces between your hardwood floorboards are more than enough for this to occur!

Pupae hatch into adult fleas that quickly look for an animal to jump on.  Pupae are stimulated to hatch by carbon dioxide, heat, vibration, and shadowing, essentially by an animal walking by.

If not stimulated, the Pupae can stay in a dormant state for up to 9 months.  That’s why the old lake house can still be infested with fleas even though it’s been dormant all winter!

I mention all this because it is important in understanding how to treat a flea problem, as well as understanding how they get on your pet.

The reason that the fall is the worst time of year for fleas is that the environment outside is perfect for them. It’s still warm, but not too hot, and the cooler evenings and extra ground moisture allow flea eggs to do very well outside.

Every night, right outside your back door, there may be raccoons, opossums, stray cats, etc. with fleas. When they hang out in your yard, they are dropping flea eggs everywhere!  Your poor cat or dog goes outside to use the bathroom and some new adult fleas hatch and jump on your unsuspecting pet. Once they come inside and start laying eggs, you’ve got a problem.

So one important point is that flea exposure is often out of your control. There will be flea exposure, and the severity of it really varies depending on where you live.

Another important point is that killing the adult fleas on your pet is easy.  Even a simple flea shampoo can easily kill all the fleas on your pet.  But the real problem is the 2000 flea eggs that are now in your home, that are quickly going to hatch and put fleas right back on your pet.

Fortunately, in 2015 nobody has to deal with fleas on their pets.  There are many excellent, and safe flea medications available. Yes, they are indeed all “pesticides” that we are putting on or in our pets.  However, most really do have a great track record of safety and walk that line of “toxic to the fleas and tick, but safe for the pet.”  I would love never to use these products on my pets, but, sorry, I’m not going to have fleas and ticks in my house and I don’t want my pets to suffer from these parasites either.

Note: flea collars, flea dips, flea powders, Hartz/Sargeants flea drops at the store, and bombing your house are all old-school, ineffective, and potentially harmful to your pet.  The newer meds like topical frontline, revolution, and advantix, or the new oral meds like Nexgard and Comfortis are very effective and generally very safe.  They all have their potential issues, and that is something to discuss with your veterinarian, but there are so many good options, at least a few of these will be appropriate for your individual pet.

Use a monthly flea preventative and you’ll likely not have to deal with these little buggers.  If you find your pet with fleas, start a monthly treatment/preventative asap, and then vacuum your house like crazy—vacuuming can be very effective at getting up some of the eggs, larvae, and pupae.  Focus especially where your pets spend the most time.  Be sure to treat ALL pets in your house. If your dogs have fleas, your cats most definitely have fleas as well.

It may take a few weeks for you not to see any more fleas once you start treatment.  There are still going to be some pupae in your house that have to hatch.  The adults will jump on your dog and then die, but it takes a few weeks for most of the pupae to finally hatch.


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