Fleas and the Bubonic Plague!

I recently read an article describing the devastation and terror caused by the ‘Black Death’ (Bubonic Plague) which killed over half of the population of my native Edinburgh in the mid 1300’s. Far more alarming was the fact that the same disease killed up to 200 million people (a quarter of the entire population) in Europe over a 4-year period! In fact, it took over three centuries for the European population to recover to pre-plague levels. Now, although bubonic plague still exists in isolated outbreaks, its effect is a lot less severe. Modern medicine has seen to that (so far, at least).

Why is this ancient history of relevance to you when you live in 21st century South Australia, I hear you ask?

Well, Yersinia Pestis, the organism which caused the plague, was carried by fleas! These particular fleas relied on rats for their survival and the subsequent worldwide spread of the plague was attributed to rats hitching a ride with naval merchant ships. Actually, local authorities recognised that there was a connection between the disease and the local animal population. Unfortunately, they picked the wrong beast and thought it was the dogs and cats spreading the problem. By culling the 4-legged population of community ‘ratters’, they actually made the problem worse!

Like it or not, if you own a dog or cat, you’ve most likely been exposed to fleas at some point in time. Although far fewer deaths are caused by the plague nowadays, we shouldn’t discount the risk of other disease-spread caused by these seemingly harmless little pests.

What do we know about fleas, then?

  • They can spread other diseases
    • As a simple example, we know that tapeworms share a common lifecycle link with fleas – if your dog or cat has fleas, they probably have tapeworm as well!
  • Flea bites are a major nuisance
    •  Both direct hosts (dogs and cats) and people can react severely to their bites
  • Many pets develop an allergic reaction to flea saliva
    • Flea allergy dermatitis is the most common cause of itchiness in pets and something we see frequently in practice
  • Fleas feed on ingested blood and can cause anaemia in some pets
    • Usually in heavy infestations and very young or very old animals
    • Occasionally this can even be fatal in young pups or kittens

There are many myths regarding the life-cycle of fleas so let’s look at this and clear up some of those misunderstandings

  • An adult flea lives most of its life on the one dog or cat
    • They don’t often jump from pet to pet or pet to person
  • Adults lay eggs which then fall of the pet and hatch out in carpets, bedding, etc
    • The larvae like the darkest most moist place they can find
    • They really don’t like being out in the garden or in sand
  • Those larvae then form pupae which can sit dormant for months
    • This explains why someone moving into a long-empty house can find themselves being suddenly bitten by fleas
  • The pupae react to vibration or movement and instantly hatch out into new baby fleas
    • These young fleas jump onto the nearest passing victim (your pet or you) and so the whole cycle starts again!
  • Fleas are extremely fertile and hatch out hundreds of thousands of eggs in a lifetime
    • Only takes a few fleas to start with to develop into an infestation if not controlled

Now we know there’s a problem out there, how do we solve it? The good news is that we can do this very effectively. Here are some tips:

  • Cats and dogs share the same fleas so you need to treat all pets in the household
    • You may not see fleas on all of your pets but that doesn’t mean they’re not present
    • Cats are good at picking off fleas but, by then, they’ve usually hatched out eggs so the cycle persists
  • Washing and vacuuming bedding or areas where your pet sleeps is a great help
    • Don’t forget to vacuum under baseboards, beside cushions, etc
  • Regular, preventive treatment is far more effective than occasional treatment once you’re already seeing fleas
    • By the time you see fleas, there are lots of eggs hatched out
  • Bravecto (quarterly chewable tablet) or Advocate (monthly spot-on) are both great at treating/preventing fleas
    • Be very wary of supermarket products – they are far less effective and generally very poor value for money
    • Please don’t rely on flea collars – they just don’t work and can actually make some pets quite sick
  • Fleas are often worse in warmer Summer months but survive quite happily indoors so treat all year round

I’m hopeful that we’ll not be seeing a recurrence of the Black Death any time soon. Nonetheless, we should stay on top of the flea problem – it’s much easier to prevent than to treat (like most diseases, we find). If you need any advice on this or if you think your pet may be showing signs of fleas, give us a call on 8522 3500 or book an appointment directly.



Picture of Anne Crouch

Anne Crouch

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