Blogs by Dr. McFadden

Rabies

     I’m going to talk about something scary today. Not an alien life form but a very real live virus called rabies. Rabies didn’t die out with Old Yeller – it is still very much with us, and definitely present in the wildlife of Merced County. In fact, Merced is considered an endemic area for the disease. We have positive cases every year! In the 30 plus years I have lived and worked here, I have watched both the Public Health Department and Animal Control cooperate to monitor Rabies positive cases turned in to the County. They map where the rabid animals were discovered, watching for “hot spots” of possible contagion in the wildlife. Positive rabid bats and skunks have been identified, often after a dog or cat has carried it into the house or killed it.

     But what about the animals that just quietly die in the wild, that may be carriers of the disease? This, of course, is how it is spread. Consider: Rabies virus enters the body through a direct bite or contact with the mucous membranes (eyes, mouth, nose). Once there, it slowly spreads into the nervous system, eventually reaching the brain. There is NO CURE for the disease at this point. In fact, only because the virus multiplies and spreads so slowly is it possible for post-exposure immunization to work and save human lives. Rabies is diagnosed after the brain of the suspect animal has been inspected. There is no way to diagnose the disease in a living patient.

     California is considered to have a high incidence of cases – over 400 cases in wildlife reported annually. Skunks and bats are the most frequent wildlife involved, but other carnivores such as  raccoons, foxes, coyotes and bobcats are often positive.

     Each year one or two cases of human rabies is reported in the United States. Since 2002, 21 of 24 reported human rabies cases in the US were linked to bats, per the Center for Disease Control (CDC). July 24, 2013 a young girl was bitten by a rabid bat at the Oakland Zoo- it was not an exhibit animal, just local wildlife. She received post-exposure immunization and is fine. Easter in Bakersfield, California of 2012 was grim for the family whose pet cat bit their child, after itself contracting rabies from area bats.

     In June, 2011 an 8 year old girl from Willow Creek, California actually survived the disease after intensive treatment at UC Davis’s Childrens Hospital. She is only the third person in the US to survive rabies without receiving the post-bite immunizations. Most people die or become vegetables. In countries where vaccination vigilance is not as high as the United States, rabies is a serious threat : 60,000 people die from this entirely preventable disease every year! Three “islands” are isolated enough to have no rabies : Hawaii, England and Australia. Travelling with pets to these places is a complicated process as they strive to remain rabies free, protecting people and their indigenous or native wildlife from sure death.

     Because wildlife cannot be vaccinated against Rabies, your FIRST LINE OF DEFENSE is to vaccinate your pets, the carnivores at highest risk of coming in contact with wildlife. ALL DOGS and CATS should be vaccinated against rabies. And you should never approach wildlife, especially when they seem sick.

     If your dog or cat is bitten by a bat or suspect carnivore that isn’t available for brain examination it is presumed exposed to a rabid animal. If the bat or skunk is confirmed positive and rabid and the dog or cat is NOT current with rabies vaccination protection it may be recommended that it be immediately destroyed. If the pet is current on vaccination, by law it will still be isolated for anywhere from 10 days to 6 months, depending on the individual circumstances of the case.

     If a human is bitten, whether it be a pet or a stray dog or cat, or any wildlife, it should immediately be reported to a physician. If the animal is available, it will be quarantined or its’ brain will be examined to check for rabies. The type of bite, animal involved, vaccination history and other factors will determine the recommendations made by your physician and public health authorities.

      This is where your money for those darned rabies licenses go. This is what it’s all about. The message : Vaccinate your pets against rabies. It’s the law – and it’s a good one!

Christine B. McFadden, DVM

 ValleyAnimalHospital                                                                                                                                   drmc@mcmenagerie.com

Heartworm

     Moonshadow gently waved his tail from side to side, tongue pink as he greeted us. The older black lab moved with a stately grace across the exam room, a gentle cough escaping from his throat. “There, did you hear that? Why is he coughing like that?”, his owner queried anxiously. I stared down at him, mind running through possibilities. Moonshadow was old, so I had to put cancer on the list. Not a happy place to start. I said nothing as I began a full exam, checking out his teeth, moving over areas where lymph nodes lurked, probing his tummy, riffling through his fur. Moonshadow cooperated with everything, seeming to enjoy it all as one big petting fest. I pulled out my stethoscope and listened carefully to his chest, timing his heart rate and listening to his lungs expand and contract with each breath. A lot of times you don’t hear much listening to healthy lungs, maybe a quiet whoosh. Today I was hearing crackles and rales, sort of like Rice Krispy cereal when you first pour the milk on. Not a good thing to hear. I stood up from the floor where I’d been kneeling at Moonshadow’s side. He side-swiped me with a lick of appreciation, then coughed gently with the extra effort. His owner, in her late twenties, shifted from foot to foot anxiously. “We’ve been through so much together. He’s travelled across the country with me.” Her voice trailed off, tears threatening. Her dog walked over to her and pushed his head up under her hand.

     I asked to run a blood panel and take a set of chest x-rays. The x-rays would show me any masses in his chest that could be cancerous or might point to an odd disease like the fungal infection Valley Fever. I could evaluate his heart size and shape and find markers for other lung diseases. The bloodwork would check for signs of infection, diabetes, thyroid disorders and see if his liver and kidneys were functioning ok. Not much point in making a diagnosis of one problem and later finding out that my patient’s renal function was toast. Obtaining a complete picture up front was in the best interests of my patient so I could help him – or know that I couldn’t, should that be the case.

     One of the blood tests was for Heartworm, Dirofilaria immitis, a long spaghetti-like worm that lives in the blood stream, bobbing around through little capillaries and veins as larvae until they eventually grow up and take up residence in the lungs and heart. There can a fistful of worms clogging the heart. Nothing microscopic about it – unfortunately, the patient is usually dead when you get to see it that graphically.

     Heartworm goes through one of its life stages in the mosquito. It is when the mosquito bites your dog, sucking out a bit of blood (the mosquito’s meal) that it injects the microscopic larval form of Dirofilaria into your pets’ bloodstream. If you give your dog the heartworm preventative EACH MONTH it kills off all first-stage larvae encountered and the story ends there. If your dog isn’t protected by a heartworm preventative, or you forget to give it for a couple weeks (even if you re-start it and get back on track), then there is a window of opportunity for the first-stage larvae to grow on to the second stage and into the adult worms living in the chest. The whole process from mosquito bite to worms clogging the lungs and heart can take up to 2 years. The symptoms your pet shows may range from something mild like restless sleeping to wheezing to full out coughing and heart failure.

      Todays’ tests are very sophisticated, requiring only a few drops of blood to detect antigen, the bodies’ response to invasion by a foreign invader, in this case the heart worm. If your dog does test positive for heartworm, a second test is done to look for actual microfilaria larvae circulating in the blood, which helps stage the disease progression and predict the prognosis for your pets chances of beating this disease.

     Is there a treatment for dogs that have heartworm? Yes, an injectable form of arsenic. Can some dogs die from the treatment or get very sick from it? Yes. Does the treatment work 100% all the time? No. Once a dog has had heartworm and been successfully treated do its lungs go back to normal? It depends. Sometimes. Can cats get heartworm? Yes, statistically 5-10% as often as the dogs in a given area of California.

     In February 2015 there were two (2) cases of heartworm diagnosed in local dogs : a little Yorkie in Merced and a medium sized dog that lives in Atwater. Both are house pets and neither has ever travelled outside of town. For years we have known that pets that travel to the foothills, such as Mariposa or Sonora, are at very high risk; also the Delta area of Stockton. Most of the United States is infiltrated, so ALL travelling dogs and cats should be on monthly preventative. Heartworm is HERE in Merced County. Most dogs can be protected for less than $100 a year. Talk to your veterinarian about the best choices for your pet and family.

     And Moonshadow? He tolerated the arsenic treatments. His lungs were permanently damaged and he needed medicine for the rest of his life to keep the post-heartworm immune reaction under control. He was a dog that appreciated everything done for him and gave another two years of love to all he met in his journey through life.

 

Christine B. McFadden, DVM

Valley Animal Hospital, Merced

To Spay Or Not

     So you think your dog is cute and your friends wish they had one just like yours? Or you think it would be good for your children to witness a live birth? Or you paid money for a dog “with papers” and now it’s time to recoup the investment? You can breed it yourself and make a fortune (no fortune, of course, if the bitch requires a C-Section to deliver, or if you have the puppies examined and vaccinated, or heaven forbid they don’t sell quickly and you have to start feeding them). Yes, mutt or purebred, you have talked yourself into breeding your pet.

     Wait a minute. Please. Just because your pet is cute doesn’t mean its progeny will be equally attractive in looks or temperament (do you follow Hollywood?). And those friends who were just WAITING to get a dog often find it inconvenient when the time comes and decide to “wait till the next litter”. And why is it that you want your kids to experience the birth, but you fail to include them in the rest of the story – the ultimate Reality Show where you find out that half of the litter is not expected to stay in its original home? Should you tell your children to choose their favorite, then “kiss the rest goodbye”? Do you know that 25 % of the dogs turned in to Animal Shelters are purebred? That you can spay or neuter your dog for less than it costs to raise a litter of puppies? That HUNDREDS of dogs are euthanized every month, not just here in Merced County, but every city and county in the United States, because we would be over-run with stray and unwanted pets if we didn’t?

 

Start with one female dog and let’s do the math (as the Arizona Humane Society did years ago):

In her first year she produces 4 pups, 2 of them females (4 total)

Second year production of first and second generation females is 12 pups, 6 female (12)

Third year production of 3 generations of females is 36 pups, 18 females (36)

Fourth year production of four generations of females is 108 pups, 54 females (108)

Fifth year production of five generations of females is 324 pups, 162 females (324)

Sixth year production of 6 generations of females is 972 pups, 486 females (972)

Seventh year production is 2,916 puppies…..

 

If you think there is a population problem in the world, it does not even compare to the population explosion in the pet world!

 

Christine McFadden, DVM

DrMc@McMenagerie.com

Valley Animal Hospital, Merced

Valley Fever in Dogs

I have followed with some interest the newspaper stories on the invasive fungus, coccidiodomycosis, that causes Valley Fever in people here, up and down the Central Valley. Coming from Arizona years ago, another dry, warm climate where the Fungal infection is extremely common, I learned a lot about Valley Fever, if for no other reason than you won’t pass the Arizona State Boards to practice there if you don’t. It’s just that common in Arizona, the fungal spores picked up in the dry winds blowing off the mountains and desert, settling in the lungs and bodies of two especially susceptible species : Man and his best friend, the dog.

This is not your everyday little athlete’s foot fungus or swimmers ear kind of yeast that creates mildly aggravating rashes and inspires odd TV commercials. While most fungi like a moist environment, they have trouble getting past the body’s great defense : skin. Coccidiodomycosis (we’re going to shorten that to “VF” for Valley Fever pretty quick here) is a “systemic” fungi, meaning the fungal spores invade deep inside the bodies’ systems and organs. I know of 3 different systemic fungi common to the United States, each found primarily in its own region of the country. For us in the Central Valley desert and arid parts of the West, we have to deal with Valley Fever.

It was July of 2011 when Mr. Cardwell brought his dog in. Named “Tick”, she was a hound of mixed pedigree (a bit of a mystery, but every girl needs that) going into her 11th year of age. “Tick” had been coughing for a couple days, just a little tickle in her throat but rather persistent. The common stuff we were looking for ran the gamut from Kennel Cough to Heartworm disease to Congestive Heart Failure to Cancer and then some. Every veterinarian’s mind has a ticker tape running through a list of disease possibilities that rivals any Wall Street machine.

We noted she had a high fever. Her weight was good, even plump. We took a set of chest x-rays, and there on the images that captured the outlines of her heart and lungs we could see a fuzzy white shadow lurking low in the right lung. Hmmm. Unfortunately, indistinct shadows are not enough to make a diagnosis (choices, always other possibilities!) and Tick didn’t seem so very sick to Mr. Cardwell. Reasonably enough he asked to treat her for something like Kennel Cough ( a story on that disease complex later, please), so we complied with a course of antibiotics and cough suppressants.

Which was all well and fine, but no one consulted Tick, and she wasn’t having any of this medicine stuff. No way, no how. After a couple of trips back to our hospital  to discuss new ways to get a pill into her, we weren’t sure if her failure to improve was because she wasn’t getting her meds or if it was time to go further in our diagnostic tests. Ten days after we’d first examined her, Tick’s fever was down, but so was her weight. She’d lost 4 pounds (she started at 28) and her lungs sounded dry and crackly. The coughing was persistent, though still more of a wheeze. Mr. Cardwell gave the ok for a battery of general blood and urine tests, which revealed that she did not have heartworm and that most of her organs were functioning well but she had a terrible infection driving her white cell count up over 36,000 (normal’s probably around 8,000).  I liken the white cells of the body to Soldiers marching off to battle disease and infection : 36,000 soldiers is a huge army. What WAS that white stuff in her lungs? We sent out a blood test checking for Valley Fever. Tick’s tests were positive on 2 out of 3 run for coccidiodomycosis. Bingo! Definitive diagnosis!

With this information, and knowing that her other tests and body organs were normal, we could recommend a treatment plan, one where she would take a powerful anti-fungal pill for a minimum of 6 months (such a long time!), and knowing that some dogs immune systems never can quite fight it off and either require medication the rest of their life or, worse, may not tolerate the strong pill necessary to save them.

Tick started her pills the next day. They had to be hidden in home cooked chicken smushed in a cheese ball. We didn’t mind. Five days later she had lost another 1 ½ pounds and was sleeping a lot, but her owner reported the cough had slowed considerably. Within 2 weeks she was jumping onto the bed at home ( it’s the little things you don’t notice fading away sometimes), had no cough, and was firmly addicted to Velveeta cheese.

Listening to her lungs through my stethoscope wasn’t quite as great an experience – that raspiness was to remain for a long time – but over the ensuing months Tick’s blood counts slowly normalized and she regained her weight. One year later she was finished with medication and deemed fully recovered, as do approximately 80% of treated dog cases. ( You may find more information at The Valley Fever Center For Excellence at the University of Arizona). Only her daily Velveeta cheese serves as a reminder of Ticks’ terrible near death experience with Valley Fever.

Christine McFadden, DVM

Valley Animal Hospital

 

Ear Jam

      Today we will tackle the shakey subject of ear infections in the dog. Ear infections rank right up there with some of the smelliest problems you might ever endure with your pet. And your dog feels a lot worse about it. The ear is exquisitely built in the dog – those long, silky flaps (pinnae) framing your dog’s face, so pettable, tilting to make clown faces, waving in the wind during a glorious ride peeking out the car window. Some ears stand upright at attention and a few are bald. All ears are beautiful. The inner workings of the ear contain the mysteries that lead to one of the major 5 senses in the body : Hearing. A dogs hearing ability is considered to be 4 times that of the average human being. Sound is caused by air vibrations – the more vibrations per second, the higher the sound. Humans are limited to hearing sounds that vibrate at 20,000 vibrations per second, while dogs pick them up at 50,000 vibrations per second. Another factor is that people have only 8 ear muscles to help wiggle their ears to funnel sound in and capture noises ; the dog has 18 muscles (Not to be outdone, the cat, with 30 ear muscles, enjoys the best hearing of all!).

     Did you know that dogs lack most of the skin glands that a person has? One place that they DO have true skin glands is lining the inner ear canal or passageway into the ear. If you gently lift your pets ear flap, or pinnae, you’ll see a hole at the base which goes into the head: this is the ear canal. The average ear canal is 2 inches long! In the dog it travels down, with a little L-shaped jog at the end just above the ear drum (tympanic membrane). This may serve to protect the ear drum from things that fall into the ear. Just as in a person, the ear drum is exquisitely sensitive, a barrier between the outer ear and the middle and inner ear where the hearing organs are located. This fine membrane vibrates in response to the sound waves it receives, transmitting them to the middle and inner ear for complex translation. Any fluid, foreign object, mass, or swelling inside the ear may deflect the passage of air vibrations and alter hearing. Long term infections may lead to permanent thickening (hyperplasia) of the canal, blocking the travel of sound.  Loss of elasticity to the ear drum may result in deafness to varying degrees. Ear infections are serious.

     So what can go wrong with an ear? How can you tell? One of the easiest things to remember is that dogs don’t really make ear wax like people do – so if you see yellow or black discharge lining the ear you know something is very wrong. This ceruminous or glandular discharge may be made up of several bacteria or yeast or both. Some people will note a bread-like odor if yeast is present, and one bacteria, pseudomonas, is quaintly referred to by its “rotten taco smell”. Because the average length of a dog’s ear canal is over 2 inches long, a veterinarian requires a specialized instrument, the otoscope, to examine deeply. An otoscope has a strong halide light and magnifying lens, coupled with a long tube sized for the individual to look deep into the canal for the cause of the problem.

     Like something out of a cheap horror movie, sometimes we put our eyeball to the scope and see giant (magnified) grey legs waving at us - ear mites, Otobius megnini. These are not to be confused with the cat ear mite, Otodectes cynotis, which would be about the size of a small grain of pepper if visible at all and never waves at you. We don’t see them that often around Merced and it’s usually good for a surprised shriek. In the USA the Otobius mite is most common in the arid regions of the Southwest and has a preference for the ear, even, occasionally, in people.

     Very commonly we find foxtails buried deep into ears, painfully jabbing the tender canal. Sometimes they can be removed with a long narrow instrument called an “alligator forceps” – your pet will let you know if sedation is required! The pointed, piercing end of a foxtail awn must feel like an ice pick is poking into their head! Foxtails in a deep ear hole are never good, as they may perforate the ear drum and travel into the head, adjacent jaw or lymph nodes. The ear responds vigorously to this foreign body, mounting a massive infection in an attempt to eject the invader; alas, to no avail as gravity keeps it buried deep in the canal. The best news about foxtails is that once removed the infections are usually responsive to medication and clear up quickly.

     Chronic, recurring ear infections are extremely common in our Valley. Properly called “otitis externa”, these infections bear no relationship to the inner ear infections young children often suffer from. They do not respond to oral antibiotics given to toddlers. They are not similar infections at all. Hayfever, or Atopy, may be behind much of the recurring or chronic infections of dogs. The ear canal of a dog is lined with true glands. Glandular tissue may respond to an allergen, like pollens in the air (and is our Valley not King of Pollen?) by becoming inflamed. Some breeds, like the Labrador Retriever and Cocker Spaniel, are genetically born with twice as many glandular cells lining their ear canals as other breeds, making them even more susceptible to ear infections. When the ear canal is examined we can see the tiny blood vessels swollen and red and the little glands puff up, making the inner ear canal look bumpy like a cobblestone road. As the tissue swells, a thin fluid exudate oozes out, creating a warm, wet environment deep in the ear hole – perfect for breeding yeast and bacteria. And do they ever! This ear soup is stuck, since it can’t drain by itself. If unattended, blood and pus may form. These infections are very painful, and a dog may paw or shake its head so hard the blood vessels burst and the pinnae fills up like a balloon with a blood hematoma. Polyps and cancerous masses can occur. All ear infections require careful treatment plans only your veterinarian can prescribe – your pets smiling face and happy head wag is its own reward!

 

Please feel free to distribute this article (at no charge) via all media— all we ask is that you give credit to the author Dr. Christine McFadden. You will find her at the best veterinary hospital in Merced, California– Valley Animal Hospital. www.vahmerced.com  and www.valleyanimalmerced.com