September 7, 2014
One of the more curious things worth pondering is the realization that “zero” is only as low as your ability to measure something, any given parameter, to zero. How much of a given substance is found in your food, how much radioactive activity persists in the ground, how fast a ball flies from the pitchers hand is all measured by a variety of instruments created by man and only as accurate as the instrument currently in use. As technology advances we are able to detect smaller amounts, faster movement, ever tinier invisible particles – and our previously accepted “zero level” decreases accordingly. Fascinating!

Enter the flea, ctenocephalides felis, the common flea of both dogs and cats despite its’ Latin name. The flea has been with us for centuries. A small wing-less creature, it can safely be described as a parasite to most of us, if we accept the definition of parasite to be an organism that exploits or lives off another organism while contributing nothing to its wellbeing. Why do we care what this little insect gets up to in its daily life?

For starters, fleas rarely appear to be doing good deeds. Once an adult flea has pounced upon a dog or cat, it will feast upon its blood (blood meal). In very small, young, or very ill pets enough fleas can together literally suck them dry of their lifeblood, leading to severe flea anemia and death.

While taking that blood meal, the flea actually injects its mouthpart or proboscis into your pets’ flesh which also introduces its saliva. Not only does your pet feel little flea feet crawling all over its skin, it can feel the sting of the bite and worse, develop an allergic reaction to the flea saliva, which will make him itch and break out in a rash. The ultimate reaction is a pet so allergic that they scratch off their hair, their skin, and develop oozing, painful sores called “hot spots”. Medical attention is required to get these under control quickly. Your veterinarian can literally start turning this condition around in hours! Hot spot and other allergy medication does not take days or weeks to work!

Which came first, the flea or the tapeworm egg? In a twist of fate, the tapeworm egg of Diplydium caninum lays on the ground or carpet. A flea larvae MUST eat it for the tapeworm to continue to develop. So the flea larvae eats the tapeworm egg. When the flea bites your pet, the tapeworm larvae is spit out on their coat. Your dog or cat turns to lick at the stinging flea bite and ingests the tapeworm larvae, which is swallowed and grows up inside your pet to become long ribbons of worm segments looped together in the intestine. Often these live segments break apart and are passed in pet feces. You may literally see wiggling flat worms (proglottids to you science types) in pet droppings or even around your pets’ tail. Once dried, they may look like rice or dried sesame seeds. They do not pass daily, so if left untreated don’t be fooled that they’ve naturally gone away if you don’t see them for a week or two. They’re still there.

Ok, so far we’ve discussed fleas on cats and dogs :
anemia, even death;
creepy crawly flea feet running on them;
allergies, hot spots;
tapeworms.

What about people?Some people are bitten by fleas. The bites can be painful, and may cause an allergic skin reaction. The kind of tapeworm, Diplydium caninum, that dogs and cats carry is NOT the tapeworm you hear people can get (they must eat a flea to get this kind of tapeworm – highly uncommon).

But there IS a zoonotic (spread from animals to people) infection fleas CAN transmit: murine typhus, a rickettsial bacteria that may be harbored in feral or pet cats, opposums, and other animals. Murine typhus is an under-discussed suburban vector-borne zoonotic  disease. In the United States California, Texas and Hawaii have had outbreaks. In California, the southern areas of the state are vulnerable. Orange County reported two (2) cases of murine typhus in 2012. When one case was reported in a young girl the county trapped feral cats and opposums near her elementary school searching for the probable source of contagion.  This disease usually responds well to antibiotics and people are easily cured. However, it is uncommon and initial diagnosis can be difficult. The primary recommendation to decrease the risk of murine typhus? 1) Do not feed feral or wild animals near your home. 2) Apply flea prevention/control products to your pets.

Which brings us to the crux of this article. How to prevent fleas on your pets, in your home, on you? Because if you live in Merced County, we provide everything a flea needs to flourish with our long seasons of warm weather and mild winters. We are a flea hospitality haven! Please tune in for Fleas: Part Two : Searching for Ground Zero

Christine B. McFadden, DVM
Valley Animal Hospital, Merced
drmc@mcmenagerie.com