September 14, 2014
In my previous column on fleas we discussed the mode of action and the suffering and disease which fleas inflict upon dogs, cats, and occasionally people.  I stated that the tapeworm of dogs, Diplydium caninum, did not infect people. Dr. Jerry Menefee of Los Banos called to tell me how much he enjoyed my column and to gently correct me: there have been a few cases of human infestation with the dog tapeworm, called Diplydiasis, primarily when a young child or infant has actually eaten an infected flea (same as the dog or cat) and the worm develops in their intestine. There is rarely any sign of illness, just little tapeworm segments passing in the diaper! Treament for the child is the same as used for the dog, with excellent success. I could find 2 medical papers printed on separate cases, one published in 1993, another in 2003. Diplydiasis appears to be extremely rare (but oh dear, aren’t you running to check the calendar to see if you’re up to date on your flea control?); I shall expose the mysteries of “human tapeworm”, an entirely different group of worms, in a future column. Today we are exploring methods of flea prevention, critical in our area because, as noted in Part One, our local climate favors fleas – we are a flea hospitality haven!

If a pest has been around this long, there’s been plenty of time to try to get rid of it. Because some pets and people seem to attract more than their fair share of attention and get more bites, researchers tried changing the way skin smells. As it turns out, fleas are NOT put off by garlic or B vitamins, nor are they scared away by clove oil, tea tree oil, cinnamon, lemon, etc. Whether ingested or applied topically, these products only make you or your pet less socially acceptable to other like creatures. Not recommended. It has been theorized that some dogs and cats are better able to groom out fleas with their teeth, so appear to be flea free and escape the ugly monikker “fleabag”.

So we’re talking pesticides to control pests. Thirty years ago we used flea powders, sprays and flea collars, all powered by chemicals in the carbamate and organophosphate family of pesticides. This group of chemicals were not at all selective to fleas – used improperly, they could poison your pet and you. It’s what we had (our “zero”), and we were desperate. The collars worked sometimes on very small pets, since they only covered the neck. Powders would do the job, if you could stand the dust all over your pets’ coat. Sprays were very effective, but required near daily application because as soon as your dog rolled in the grass they were lost in the dew. Forget spraying a cat- one puff and that cat was in the next county. Dips were also effective, though again, none lasted two weeks as dogs roll in the grass…..removing the substance. Most flea dips were toxic to cats, so if applied incorrectly to a cat it would die unless emergency treatment was sought. I spent hours counselling on time consuming methods of flea control that no one thanked me for.

Pest control companies were kept busy spraying yards and houses in an effort to control the flea in the environment. One product, malathion, a mainstay in pest control years ago, to overcome flea resistance had to be sprayed over your entire yard every 10 days to have any efficacy at all according to UC Davis! DIY (do-it-yourself) friendly, it was not. Again, clients were grumpy to receive this news. Today there are a rotating group of pesticides used by pest control companies to fight the flea and prevent resistant strains from developing. Environmental control in the yard is very important; even if your own pet never leaves home, wildlife and roaming pets will almost certainly introduce fleas. Your pet does not live in a bubble!

And then a new generation of medications were discovered. Wonderstuff. Applied topically to the skin of the pets neck or given as a chewey pill, and only ONCE a month, this stuff is amazing! This stuff works! Several products exist for both dogs and cats, all kill fleas within 12 hours of contact with the pet. Reinfesting fleas, flea eggs and larvae in the environment are killed following contact with the treated dog or cat. If you do no environmental control, expect it to take about 90 days to clean up your flea problem. Some of the chemical names we’ll discuss are imidacloprid, spinosad, fipronil and afoxolaner. Ahhh, what’s in a name? Tongue twisters all – the brand names are easier. Curiously, most of these products weren’t developed specifically for your pet.

Spinosad is a pesticide developed to safeguard our food supply, used commercially on fruit and vegetable crops. Spinosad is considered an “organic” insecticide found in a bacteria from sugar cane. Spinosad is considered a natural product, given a Class B designation for pregnant women: No evidence of risk in humans.  It is used on people in medication for human head lice. On dogs and cats it has been found effective primarily against only the flea.

Imidacloprid, another flea fighter available for dogs and cats, is also used on crops and home back yards. Acting as a neurotoxin to insects, when used IN THE YARD, it is a systemic chemical that is taken up by plant roots to its leaves, where sucking/chewing insects will ingest it and die. There has been some question if imidacloprid may adversely affect honeybees (colony collapse disorder), though bees do NOT chew flower or plant parts.

Fipronil is an insecticide that affects the nervous system of insects via pathways that don’t exist in mammals. A broad spectrum insecticide, it is highly toxic to fish and bees. It is widely used for protection of rice crops, field corn, and golf course lawn care. Humans can prevent tick bites by applying it (as directed) to their ankles and wrists. Fipronil can kill rabbits – do NOT use on rabbits for flea control! That said, for years the State of Hawaii has required the veterinarian-only application of Fipronil, specifically, to all dogs and cats 10 days prior to travelling to the state. Fipronil has been widely questioned in honeybee colony collapse disorder.

Afoxolaner is in the newest class of chemical, this one without apparent crop/plant use. It’s sole use is flea AND tick control in dogs. It’s a new isoxazoline parasiticide (I had to read that, why not you?) – its’ claim to fame is that it controls both fleas and ticks via an oral medication for an entire month. Tick control has always been difficult in dogs, and there are many serious tick-borne diseases. The class of isoxazaline drugs may be a breakthrough for livestock that suffer from both ticks and tick borne diseases worldwide.

The flea is here to stay. With considered use of the available products you may be able to control you and your pets’ exposure to fleas and the consequences of flea bites. We aren’t talking eradication. You are not expected to reach Zero.  As for your children, your home and yard, the truth is that flea control on the pet is not deemed of sufficient quantity to add to or create environmental issues at this time. Most of the products we’ve discussed are carried home from Garden Centers and Big Box stores by the quart and gallon weekly as yard and grass treatment for indiscriminate use and disposal by the homeowner. These products all appear much safer for mammals – you, your children, your dogs and cats – than previous options, and every year newer products are developed as we all cope to care for each other and our earth.

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

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

August 27, 2014
People love the word “mange”. “He’s just a mangey old alley cat” someone will say. Used as a description for a pet with scruffy fur or unsightly skin, most people don’t realize that mange is a group of very specific skin diseases caused by parasitic mites. There are different sorts of mites, all possessing eight legs and often only visible under a microscope. There are two kinds that commonly affect the dog.

Sarcoptic mange is caused by an ugly little mite, sarcotes scabei, that burrows into the skin of both dogs and people. Often called “scabies”, it is feared primarily because of its transmission both from dogs to people and between people. Excellent treatment protocols are available for this disease.

Demodex or demodectic mange is an entirely different skin disease. First, it is NOT contagious to other pets or people. Second, the demodex canis mite burrows very deeply into the hair follicles of the skin and is sometimes harder to treat than sarcoptic mange. Puppies contract it while nursing from their mothers (strange but true). There is some thought of either an inherited predisposition or a depressed immune system allowing the pups to express the disease visually, as not all pups in a litter may be affected. When first seen, a puppy may display only a bare patch around one eye. It’s not painful and doesn’t itch, but usually looks so unsightly that it causes immediate alarm. Often the mite doesn’t show up until the pup is over six months of age, which confounded scientists trying to understand the connection between exposure and disease expression for years. For some puppies the disease can be far worse than an unsightly bald patch. The entire body may lose hair in a case of generalized demodecosis, with scabs and sores erupting as a secondary bacterial infection kicks in. Edema and swelling of the face and feet are common, making a pup truly miserable. These puppies are extremely ill, their immune system is gravely compromised and some may die.

Because the skin can only react in a limited number of ways to any disease, signs of hair loss, open sores and itching can be caused by a variety of problems : other parasites, allergies, staph and other bacterial infections, fungal infections. A veterinarian needs to examine your pet to make the correct diagnosis. A skin scraping is diagnostic for demodex- but not always for sarcoptes. A sharp blade is used to literally scrape any potential mites off the skin and the slide is examined under the microscope. Positives are slides that wiggle back at you!

Fortunately, there are several treatment options available for demodectic mange. Thirty years ago a breakthrough dip was discovered, which revolutionized the old “cover ‘em in tar” treatment. Today that dip is less frequently used as new oral and topical medications have been developed, which when combined with antibiotics and medicated shampoo treatment protocols have greatly improved the cure rate for this disease. Once treated, dogs are cured of demodex, though if allowed to breed there is a strong risk they will pass it on to some of their offspring.

Perhaps my most memorable suspect demodex case occurred a few years back. The young German Shorthair Pointer presented with some hair loss around her muzzle. The skin scraping was negative, so I started a fungal culture for ringworm. Cultures take about two weeks to run their course. When the ringworm culture was negative, the Pointer returned for a recheck. The lesions were spreading, red sores and deep cracks tracing from the bridge of her nose down the sides of her face and lips. The rash was especially bad just below her eyes, though her eyelids were surprisingly clear, the skin untouched by disease. The rest of her coat remained beautiful. I again did a skin scraping, and when negative, repeated the test. Negative. Convinced as I was that this must be demodex, I told the owner that we would start therapy immediately before this could spread further.

When I next saw the dog she was the picture of health. Her face was completely clear, new hair growing in on smooth skin. I glowed. Success is wonderful. It was the client, of course, who set me straight. A bachelor who did most of his own cooking, and not too elaborate, thank you, he frequently fixed up a can of beans. Seems the Pointer liked beans too, straight from the can. He caught her burying her nose in deep to reach that last drop.  Her face cleared up as soon as he found another disposal system for the cans. My antibiotics probably helped the secondary infection but there was no denying that my years of training had let me down. The medical texts on mange variations do not mention bean-can-itis.

Christine B. McFadden, DVM
drmc@mcmenagerie.com