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Preventing Heartworm
It was the last thing her owners were expecting; the news was devastating. Seven year-old
Tiffany, the apple of her owner's eyes, was positive for heartworm.
Tiffany, the 9.5 pound Lhasa who spent her days on her owner's laps
and her nights on their bed had contracted a potentially life-threatening
parasite. They needed to take action immediately, starting with
understanding what they were up against
Heartworm is just that; a worm that lives in the heart and pulmonary
(lung) vessels. Heartworm is spread by mosquito, so even a dog who
spends 100% of her time indoors is still susceptible to exposure.
Basically, a mosquito bites a dog that has circulating microfilaria (the
offspring of the heartworm.) As the mosquito ingests a bloodmeal, it
ingests these live microfilaria. There is a maturation phase that takes
place in the intestine of the mosquito where the microfilaria develop into
the larval form. When the mosquito bites the next dog, these larval forms
are injected into the new host. Over the next several months, these
larvae undergo additional molts and travel throughout the new host's
body, eventually making their way to their ultimate destination: the heart.
Adult heartworm can range in size from two to fourteen inches and their
physical presence in the heart can lead to congestive heart failure within
months to years, depending on the number of worms present.
Heartworm is a preventative disease. Prescription medications can kill
the infective larval forms before they have a chance to develop into
adults. Several products are available in tablet or liquid form. Dosing,
depending on the product chosen, may be daily or monthly. The choice of
medications will be influenced by the prescribing veterinarian's
knowledge of the individual patient and the patient's risk of exposure. It is
ABSOLUTELY NECESSARY that any dog who has not been on
continuous heartworm preventative be blood tested before starting on
preventative medication as there is a risk of circulatory collapse and
death if a dog with circulating microfilaria is put on certain heartworm
preventatives.
Heartworm can be eliminated from the body by treating with intravenous
or intramuscular arsenic compounds. The treatment is usually expensive
and carries significant risks; the goal is to kill the worms without killing
the dog. PREVENTION IS THE KEY!!!
Tiffany's owners were vigilant about making sure that she was given
(and swallowed!!!) her heartworm preventative. In retrospect, it appears
that she contracted heartworm because she was underdosed with
preventative. The preventatives are marketed for different weight
classes, and at a critical time during last year, Tiffany put on just enough
weight to put her over the cutoff. The result is that Tiffany must now
undergo the heartworm treatment.
On the upside, Tiffany was diagnosed heartworm positive by the
bloodtest conducted during her annual exam. At this time there are no
clinical signs of heart or lung damage. She appears to be in good health
and is a good candidate for the treatment. Her case is a good illustration
of why annual bloodtests are so critical; had her owners declined the
test, their first indication that Tiffany was heartworm positive may have
been because she had advanced into congestive heart failure.
It will be six months or so before Tiffany finishes all the steps needed to
rid her body of the worms. By this time next year, she is expected to be
back on monthly preventative, but on a higher, more appropriate dose.
Tiffany's owners and veterinarian have learned an expensive lesson.
by Dolores Roeder, DVM
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Caring for The Geriatric Dog
Elderly dogs, like elderly people, experience age-related changes. These
changes are insidious and often go unnoticed by their owners, since
they feel they are normal changes.
Symptoms may include disorientation, changes in sleep/wake cycles,
loss of house training, and reduced interaction with family members.
When those signs are all seen together in geriatric animals, the condition
is termed Canine Cognitive Dysfunction Syndrome (CDS).
CDS is an age-related deterioration in the dog's cognitive abilities that
cannot be attributed to metabolic disease or organ system failure. CDS is
often referred to as "old dog syndrome" or senility.
There seems to be no difference in ratio of males to females that are
affected. A total of 15 percent of 11-12 year olds met strict definition
criteria for dementia, as did 21 percent of 13 and 14 year olds. In
15-year-old animals, 50 percent of pets had dementia.
CDS is diagnosed by exclusion. This means that all diseases, both
metabolic and neurologic, must be ruled out before a CDS diagnosis is
made. Therefore, the dog must undergo a thorough physical and
neurologic exam and history, and a minimum database. This would
include blood work and urinalysis. CT (Cat) and MRI scans are usually
low-yield in this disease and not normally done.
It is imperative that the pet be evaluated, as some medical conditions
(such as loss of vision and ability to hear) can lead to behavioral
changes that mimic CDS.
Unfortunately, there is no cure for CDS. Pfizer, a pharmaceutical
company, is currently attempting to get a drug through FDA approval that
would be used for CDS patients. The drug, Anipryl or selegiline
hydrochloride, is currently being used in Canada. We anxiously await
approval for the U.S.
CDS is a common recognizable disease in older pets, since our senior
pets play such an integral role in our lives. Since CDS manifests itself
through behavioral signs, the pet owner plays a key role in identifying
these changes and bringing them to the attention of their veterinarian.
by Sharon Zaccone, DVM
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An Emergency Birth
It all began with the female lowland gorilla, Juju, and complications of her pregnancy. The
problem (bleeding) became severe enough that I was concerned for the
life of the mother and infant, if she were allowed to give birth naturally
(i.e. unsupervised). Within 24 hours, an expert team of five physicians
was consulted and gathered at the zoo's veterinary hospital along with a
scrub technician from Memorial Hospital, a senior medical student, and a
Denver Zoo veterinarian and technician.
It was New Year's Eve and we were performing a caesarian section on
Juju to save her and her infant. From previous ultrasounds we knew she
was very close to term. Due to Juju's precarious status, we were
prepared to give her a blood transfusion from the other female gorilla,
Roxie. The surgery went so well that this added risk was not necessary.
The only other documented case of a c-section on a gorilla in the United
States was on a healthy mother at the Los Angeles Zoo in 1978.
The infant female was stressed and the umbilical cord was wrapped
around her neck. With the physicians' help we resuscitated her until she
was breathing 100% oxygen adequately on her own. Later that night I
celebrated New Year's with a sigh of relief while the baby gorilla enjoyed
a bottle of 5% dextrose. Tracey Anderson, our veterinary technician,
and I moved into the zoo's hospital to give 24-hour care to the fragile 4-lb.,
12-oz. Newborn.
Once the infant was stable and nursing a bottle well, we offered
her back to Juju in hopes that she would nurse effectively. Juju has
never raised her own infants due to problems with letting them nurse.
We were delighted when we observed nursing several times, but
apparently it was not enough for the infant and she became very weak.
The decision was made to remove the infant to save her life, again. The
infant was very cold and dehydrated and had lost nearly a pound. After
treating her with intravenous fluids and antibiotics she was again nursing
well--only to develop seizures later that night! An emergency blood test
indicated possible infection with meningitis. Valium controlled her
seizures while antibiotics fought the infection. After 24 hours the
seizures did not recur.
We hand-raised her and for eight months there were no further
problems.
by Della Garell, DVM
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Zuri's Story
Zuri, the Cheyenne Mountain Zoo's female western lowland gorilla, had a
rough start in life.
Born by C-section on New Year's Eve
1996, she started to suffer serious seizures when she was just 8
months old. But, until recently, she had grown into a perfectly normal,
happy gorilla.
When Zuri had three seizures in a cluster of a few days, we ruled out
several possible diseases with laboratory work that had normal results.
With the generous help of our pediatric neurologist, Dr. Robin Morgan,
and a very patient technician, we were able to get an EEG
(electro-encephalogram) on Zuri.
It is no small feat to attach a dozen electrodes to a fussy gorilla's head
without her knocking them off, and then encourage her to fall naturally
asleep. With persistence, we were successful.
The results of the test were normal. In fact, the tracings looked identical
to those of an 8-month old human.
The next step was a spinal tap, under anesthesia, to evaluate her
cerebrospinal fluid. Results from those tests were mildly abnormal (for a
human patient), but did not pinpoint a cause for her seizures.
With no conclusive results, we explored the possibility of a MRI exam of
her brain. Of course, the zoo does not own such an expensive
machine. So radiologist Dr. Kathy Davis of PenRad and the local hospital
(Penrose Hospital) donated the use of their MRI facility.
Again, Zuri needed to be sedated to lie still for the exam. The results of
the MRI were also completely normal. There was no sign of any palsy or
hypoxia from her difficult birth. Dr. Davis commented that, except for her
jaw and tooth structure, Zuri's MRI looked just like a human brain.
At this point, with no indication of any abnormalities, the medical team
considered idiopathic epilepsy as her diagnosis. This means epilepsy of
unknown origin. It is the most common form of epilepsy in humans.
Zuri then had another cluster of seizures. We rushed her to the
neurologist hoping to catch a seizure on an EEG tracing. This time, she
was quite irritable, but did eventually fall asleep in my arms and actually
had a small seizure, which we captured on the EEG. It looked like
idiopathic epilepsy. With her two clusters of seizures, we decided to
treat Zuri with an oral anti-seizure medication, Phenobarbital. It comes in
a cherry-flavored syrup that she takes readily from her keepers twice
daily.
At this time, Zuri's seizures are well controlled, and she's eating well and
getting good at knuckle walking. It's possible that this may be a
"childhood" disorder, and she may outgrow it as many human patients
do. We all hope that this is the problem, but only time will tell.
The next step for Zuri, however, is quite exciting. The Toronto Zoo has
a good troop of gorillas with a female that loves to "adopt" orphan
infants. It is important for Zuri to become part of a gorilla family so that
she can behave as a gorilla would and perhaps mate and rear her own
offspring. To this end, Zuri left the Cheyenne Mountain Zoo and went to
become part of the gorilla family at the Toronto Zoo.
The zoo veterinarians up there were fully updated on her condition
and are taking great care of her.
We'll miss little Zuri here at Cheyenne Mountain Zoo, but we've always
done what's best for her medically and now we can do the best possible
thing for her normal social development. Good luck, Zuri!
by Della Garell, DVM
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A Stuffed Animal, Not!
Four-month-old Turbo was having a rotten day. By the time his owner got home from
work, the pit bull puppy had christened almost every room in the
apartment with a particularly foul-smelling diarrhea and bile-colored
vomitus. The pup lay motionless in the corner in a crouched position,
moving only his eyes as his owner called the vet for an emergency
appointment.
Turbo's trip in the car was no better than the rest of his day, as the
motion of the vehicle prompted him to bring up additional fluid. His owner
was not pleased when the receptionist instructed him to leave Turbo in
the car until his appointment was called. As much as an inconvenience
this may have appeared, the receptionist's reasoning was rational.
Turbo's clinical signs were consistent with a very contagious infectious
disease that pit bulls appear particularly susceptible to: parvovirus.
At four months of age, Turbo had not yet completed his vaccination
series and was still at risk. It was better to leave him in the car so that if
he did have parvovirus, he would not put the other waiting animals at risk,
and so that he was not exposed to whatever the other animals may have
been carrying.
During the physical exam, Turbo had exhibited many of the classic signs
of parvovirus: the profuse vomiting, the sewage-smelling diarrhea, the
abdominal pain. The lethargy and the dehydration were all consistent.
A puzzling discrepancy, though, showed up on his bloodwork. Instead
of the classic decrease in white blood cells expected with parvovirus,
Turbo's were significantly elevated; 40,000 as opposed to a high normal
of 18,000. Something else was up...
Turbo was taken to radiology for an X-ray of his abdomen, where the
answer became clear. There on the film was the obvious shadow of a
dense metallic object - presumably a coin. However, there were also
dozens of metallic fragments all intertwined into a large sausage-shaped
mass. Guesses as to its identity ranged from Brillo pads to twist-ties, but
no one was willing to back up their bets. Only surgery would tell.
Turbo was anaesthetized for surgery, but as the doctor pulled Turbo's
tongue forward to insert the endotracheal tube (the tube inserted into the
patient's windpipe to deliver oxygen and anaesthesia during surgery),
she noticed something odd. Deep under Turbo's tongue was a very fine
infected line. Probing into the tongue itself, a piece of clear nylon cord
was found cutting deep and disappearing into the meat of the tongue.
The cord was grasped with forceps and cut, but pulling back on the
pieces, the vet encountered resistance and stopped. Obviously, this
cord had been strong enough to cut the tongue, so she was not about to
cause similar damage to the esophagus and stomach. The exploratory
surgery would have to proceed with the clamps still attached to the cord,
still in Turbo's mouth.
Finding the affected intestine was an easy task - instead of laying flat like
an egg-noodle, Turbo's small intestine was bunched up like Christmas
ribbon candy. Instead of being
a healthy, fleshy pink, the intestines were an ugly, irritated red. Making an
incision into the small bowel, the coin (which by now was one expensive
penny) was readily retrieved.
Next came the more difficult and dangerous task of removing the metal
fragments that jam-packed the corregated loops of intestine. As the
offending material was removed, the identity remained a mystery. (It was
only when the owner went to use his "Sega Play Station" that he found
that Turbo had convincingly destroyed the associated wiring.) Once
tension had been relieved, it was possible to release the clamps in
Turbo's mouth and gently coax the last of the cord out through the
intestinal incision.
Fortunately, while there was some damage done to the lining of the
intestine, no sections of intestine needed to be removed. Turbo was
lucky.
Within hours of surgery, Turbo's condition had improved dramatically. By
the next day, he was up and demanding attention and food. Two days
later, he was home in a now "Turbo-proofed" apartment.
Puppies need to be treated like children. Electrical outlets need to be
covered, cabinets need to be barred or locked, and small objects need to
be picked up and kept out of harm's way.
Coin ingestion is relatively common, and not all dogs that are guilty of
eating money are going to wind up like Turbo. For those that are lucky,
the coin may quickly pass through into the large intestine where it is likely
to pass without much more than a little straining.
Occasionally, the coin can get stuck in the small intestine, but as in
Turbo's case, there is often other foreign material that is involved, kind of
catching the coin in a "net." In some instances, the coin can get hung up
in the stomach, where the stomach acids can react with the metal and
cause some very serious metabolic inbalances.
Overall good advice is to "puppy-proof" the house as carefully as you
would "child-proof" it. The few minutes it takes could save your new
best friend's life.
by Dolores Roeder, DVM
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Flea Products: Know What You're Using!
Cricket the cat was a happy, healthy 2-year-old indoor feline whose life's
ambition was to dance with the sunlight that filtered through the curtains
and to stir up the "dust bunnies" that seemed to multiply under the bed.
Her days of contented leisure were cut short when her owners made the
fatal mistake of picking up an over-the-counter topical flea medication and
applying it to Cricket without reading the label. The owner saved five
dollars, but it cost Cricket her life.
There are so many flea products available to the consumer that it is
possible to be numbed into forgetting that these products are potentially
dangerous. Advertisements for "easy to apply" and
"long lasting" topicals are enticing; who wouldn't be
interested in a liquid you apply once behind the neck and then don't need
to apply again for another month?
Two excellent cat-approved topicals include Frontline by
Rhone Merieux (active ingredient: fipronil) and Advantage
by Bayer (active ingredient: imidacloprid. Both of these products have
been specifically used safely and effectively on cats.
Unfortunately, some consumers have confused some over-the-counter
DOG products with these, resulting in fatalities like Cricket's. Often,
the active ingredient in these over-the-counter products is permethrin, an
insecticide that is specifically contraindicated in cats. Cats lack the ability
to break down and detoxify the permethrin fast enough to avoid
intoxication.
Despite blatant warnings on the front of the over-the-counter products
and the repeated warnings in the directions section, owners who apply
permethrin-containing products risk seizures, coma and death to their
feline pets they apply these topicals to.
In one instance in New York, applying the over-the-counter permethrin to
the dog in the house resulted in the death of the companion cat when the
dog and the cat cuddled together on the couch within an hour of applying
the permethrin to the dog. The cat started seizuring within six hours and
died despite medical intervention.
One sure way to avoid such a costly disaster is to ALWAYS read
the label of any product you use on your pet. Such common sense
DOES save lives. Ideally, you should consult your pet's veterinarian
to discuss your pets individual needs. Your pet is a member of your
family and relies on YOU to make the best decisions on his or her
behalf.
by Dolores Roeder, DVM
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'Takin' With A Rare Birth
Eight o'clock Sunday morning, January 26: a phone call wakes me with the surprising
good news of a takin birth. There was no observed mating 7 months
ago. Apparently, they are secretive. The 500-pound mother did not
show any physical signs of pregnancy either.
Only five zoos in the country have these rare muskox-like animals from
China. I rushed to the zoo to check on this very special calf. Two other
zoos have had fatal complications of birth for the mother or the calf or
both. Only San Diego Zoo, the source of our pair, has had survival of
both mother and calf.
After a strong start and good initial mothering skills for this first-timer, it
became apparent that the calf was getting weak. By Monday morning, he
had not been observed to nurse and we intervened with a blood test that
confirmed lack of nursing. As with giraffe and other hoofed animals,
nursing the special first milk is critical for getting immune antibodies to
protect the calf until he starts making his own antibodies. After 24
hours, the only way to get this passive immunity is via a plasma
transfusion.
San Diego Zoo offered to send a unit of takin plasma, which we
transfused into him. (A side effect of this transfusion is exposure to the
anesthetic that is circulating in the donor animal. During his transfusion,
our calf promptly became anesthetized. I was able to reverse most of the
anesthetic effects with IV reversal agents).
In his weakened state, our calf developed a bad case of dysentery,
which quickly became life threatening. He was under intensive care as I
monitored him anxiously throughout Monday night hoping our IV fluids and
multiple medications would pull him through. By Tuesday afternoon, he
was showing some signs of improvement.
He would stand if propped up, but still no nursing reflex. We continued to
feed him via a stomach tube and intravenously. Wednesday: he was
looking quite a bit better; his diarrhea had subsided and he was getting up
on his own and "head butting" as he looked for milk. He still would not
suckle a nipple however, so we took a chance that his mother would
accept him back and he might "latch on" to the nursing idea. Mom did take
him back, but he quickly weakened without nursing from her.
Back to the hospital to replace the IV units. His condition again
deteriorated with more severe diarrhea. He hung in there though, and
finally on Saturday morning he suckled for the first time after receiving an
IV dose of painkiller for a possible gastric ulcer. He has improved
dramatically since then. He is off almost all of his medications and is
drinking canned goat milk by the liter daily. He is now down to five
feedings daily and instead of 24-hour care, and he is stable enough to be
alone from 11:30pm to 7:00 am.
This is a very significant birth for the zoo. We are now one of only three
zoos in the Western Hemisphere to have a calf survive, and only the
second to have both mother and calf survive. This calf's sire, "Ghengis",
is only the third surviving takin born in this hemisphere. This calf's
grandparents were the gift of the People's Republic of China to the San
Diego Zoo.
The Zoo and the Veterinary Department all pulled together, (with some
putting in over 100 hours in a week) to help this calf survive. He still has
some problems and challenges, but I am breathing a sigh of relief that he
is out of immediate danger.
We hope to train him so that he can be socialized with his mother and still
get bottle-feeding from us. With any luck, he will be on exhibit in the near
future.
by Della Garell, DVM
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