Canine Heartworm
Dogs are considered the definitive host for heartworms (Dirofilaria immitis).
However, heartworms may infect more than 30 species of animals (e.g., coyotes,
foxes, wolves and other wild canids, domestic cats and wild felids, ferrets, sea lions,
etc.) and humans as well.
When a mosquito carrying infective heartworm larvae bites a dog and transmits the
infection, the larvae grow, develop, and migrate in the body over a period of several
months to become sexually mature male and female worms. These reside in the
heart, lungs, and associated blood vessels.
Even as immature adults, the worms mate and the females release their offspring
(microfilariae), pronounced: (micro fil ar ee), into the blood stream.
The time elapsed from when the larvae enter the dog until the minute offspring can be
detected in the blood (pre-patent period) is about six to seven months.
The male heartworms (four to six inches in length) and the females (10-12 inches)
become fully grown about one year after infection, and their life span in dogs appears
to be at least five to seven years.
Female heartworms bear live young – thousands of them in a day.
The microfilariae – circulate in the bloodstream for as long as three years, waiting to
hitch a ride in a bloodsucking mosquito.
They undergo changes in the mosquito that prepare them to infect a dog, and they
transfer back to the original host species the next time the mosquito bites.
The process of change in the mosquito takes about 10 days in warm climates, but
can take six weeks in colder temperatures.
While in the host, the worms grow and multiply, infesting the chambers on the right
side of the heart and the arteries in the lungs. They can also lodge in the veins of the
liver and the veins entering the heart.
The first sign of heartworm infestation may not manifest for a year after infection
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Parasitic worms have 5 larval stages and are termed "L1", "L2", "L3", etc.
Heartworm microfilariae are first stage larvae: L1's.
Within the mosquito's body, the microfilariae will develop to L2’s and finally
to L3’s, which is the stage capable of infecting a new dog. How long this
takes depends on the environmental conditions. In general, it takes a few
weeks.
A minimum environmental temperature of 57 degrees F is required
throughout this period. The process goes faster in warmer weather.
When a dog is bitten by an infected mosquito, the L3 is not deposited
directly into the dog's bloodstream. Instead, it is deposited in a tiny drop
of mosquito saliva adjacent to the mosquito bite.
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There must be enough humidity to prevent this droplet from evaporating
before the L3's can swim through the mosquito bite and into the dog.
Once safely inside the dog, the L3 will spend the next week or two
developing into an L4 within the dog's skin.
The L4 will live in the skin for three months or so until it develops to the
L5 stage and is ready to enter the dog's circulatory system.
The L5, which is actually a young adult, migrates to the heart and out into
the pulmonary arteries (if there is room) where it will mate, approximately
5-7 months after first entering the new dog.
Mosquito lifespan is ~35 days
An important basic concept in the treatment of heartworm infection is that
there are adult heartworms in the heart and pulmonary arteries to be killed and
there are microfilariae circulating in the bloodstream to be killed and one
medication cannot be used to do both jobs.
Heartgard30 and Interceptor, the main heartworm preventives available
commercially, will kill microfilariae.
Dogs on heartworm preventive, even if infected with adult heartworms, will not
test positive for microfilariae.
L3's are readily killed by Interceptor but not by Heartgard30.
Interceptor and Heartgard30 both act primarily on the L4's living in the skin.
After a dose of either medication, any L4's present will be wiped out.
Heartgard30 is also able to kill the younger L5's.
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DIETHYLCARBAMAZINE (FILARIBITS made by Pfizer).
Diethylcarbamazine, known as “DEC” and sold under the trade name Filaribits,
must be given daily during the heartworm season and 2 months following to
prevent heartworm infection.
It acts by killing L3’s and L4’s before they develop further and begin their
migration into the vasculature.
This approach is started right at the start of the mosquito season and must be
continued for sixty days after any frost, or it may be continued all year.
However, you must be aware that forgetting to give your pet his daily treatment
for a day or two during the height of the mosquito season could possibly put your
pet at risk.
DEC does nothing against other common parasites but is available with
Oxybendazole added (Filaribits Plus) to control hookworms, whipworms, and
roundworms.
Macrocyclic Lactones____________
IVERMECTIN (HEARTGARD30, Merial, Iverhart, Virbac) given once a month
instead of daily.
This medication utilizes an extremely low dose of ivermectin which is adequate
to kill any L4’s which are inhabiting the pet’s skin tissues at the time the
medication is given. In other words, infection takes place but is halted every
month when the medication is administered.
If ivermectin is inadvertently given to a heartworm infected dog with circulating
microfilariae adverse reactions would not be expected; in fact, this product is
commonly used in the treatment of active infection to clear microfilariae safely.
This means, however, that giving this product to a dog with heartworm will kill all
circulating microfilariae and the dog will test erroneously heartworm negative by
Difil or Knott’s testing.
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In addition to killing microfilariae, ivermectin will also suppress reproduction in
the adult female worms.
There is also a phenomenon called the “Reach back effect.” This means that if a
dog goes off heartworm preventive medication for a prolonged period (four
months was the time tested), re-starting ivermectin could still prevent adult
heartworms from developing in the heart.
Ivermectin at the heartworm preventive dose is not strong enough to kill
common intestinal parasites but it is available with pyrantel pamoate included
(Heartgard30 PLUS) to control hookworms and roundworms.
There are breed related sensitivities with ivermectin (i.e. collie-related breeds
have some difficulties) though at the very low doses used in the prevention of
Heartworm disease are not a problem for any breed.
There have been numerous discussions about the safety, or lack of safety, of
using ivermectin-based heartworm prevention in collies and other herding breeds
of dogs. You should ask the breeder of your collie if a sensitivity to Ivermectin
has been noticed.
The drug can be very toxic to Collies, Border Collies, Australian Shepherds, and
Collie cross dogs. Therefore great consideration should be used in treating these
breeds with an Ivermectin based preventative. To be completely safe, Collies and
collie breeds should be given either carbamazine heartworm preventative (daily
dose), or the monthly Interceptor heartworm preventative.
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MILBEMYCIN OXIME (INTERCEPTOR & SENTINEL made by Novartis) is
the chief competition of Heartgard30.
This product is also given monthly, also clears microfilariae, acts by killing all
L3’s and L4’s accumulated in the month prior to administration, and will suppress
female worm’s ability to reproduce.
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There are a few important differences to note, though. If milbemycin is
inadvertantly given to a dog with active heartworm disease, the dog may
experience a serious shock syndrome if an especially high number of
microfilariae are circulating.
The ivermectin product is better able to kill young adult heartworms.
Milbemycin, however, is able to control roundworms, hookworms, and whipworms
without the addition of a second parasiticide.
Milbemycin is also available combined with Lufenuron for the control of fleas.
There are no breed- related sensitivities for milbemycin.
Milbemycin oxime is also used effectively in the treatment of at many times the
dose in Heartgard. demodectic mange.
MOXIDECTIN (PROHEART made by Fort Dodge) is a derivative of
ivermectin and the same rules that apply for Heartgard30 should apply to this
new product. As is Heartgard30, ProHeart is a monthly tablet available in a 6tablet package. Not available in the U.S
Selamectin (Revolution, Pfizer) applied topicaly to prevent heartworm disease.
Feline Heartworm
Although heartworm is seen less frequently in cats, the disease poses a much greater
danger. The outcome is often fatal.
There currently are no drugs approved for fighting heartworm in cats. Cats can be
treated with canine medications, but this can lead to dangerous side effects, including
lung failure and death.
The good news is that there are heartworm prevention drugs available for cats.
Alternative Heartworm Treatment
How is Heartworm treated?
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Conventional treatment includes preventative medication as well as treatment aimed
at eradicating the adult worms from the heart and lungs if the infestation reaches an
advanced stage.
While conventional prevention and treatment of heartworm is very effective, it is
increasingly being acknowledged in the veterinarian profession that there are a
number of health risks associated with this form of treatment.
Preventative medication used for heartworm is not really preventing the infestation - it
is a way of killing off the larvae circulating in your pet's body during the early stages before they get to adult stage and cause damage.
The chemicals used in these drugs are pesticides. Although they are used
preventatively in small amounts, the damage to the animal's system is cumulative.
Some side effects listed for heartworm.
Some side effects listed for heartworm preventative drugs are weakness, vomiting,
convulsions and diarrhea.
More importantly, regular use can weaken your pet's immune system and place strain
on kidneys and liver.
This can result in greater susceptibility to infection and other diseases.
Many holistic vets are of the opinion that long-term use of heartworm prevention
drugs is one of the factors in the development of diseases like skin allergies, arthritis,
liver and kidney diseases and even some forms of cancer
There are many holistic and homeopathic vets who will very successfully treat
heartworm and many other medial conditions without making use of synthetic drugs.
There are also many integrative vets who are conventionally trained but who are
increasingly making use of herbal, homeopathic and other natural treatment
programs in the interests of promoting the health of their patients and not only curing
conditions in the short term.
Heartworm disease is a serious condition and should not be taken lightly. However, it
is important to know that there are options and alternatives to conventional treatment.
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Alternative treatment and prevention of heartworm
Preventing and treating heartworm using alternative medicine and natural
means is not as simple as swallowing a pill
1. A healthy diet is the best medicine!
Holistic vets agree that processed commercial pet foods are one of the factors
undermining pet health.
A diet consisting mostly of raw food and fresh water is one of the best things you can
give your pet to protect him against all sorts of infection, including heartworm
2. A healthy immune system will protect animals against
parasites like heartworm
An animal with a healthy immune system will be less likely to become infected with
internal parasites, including heartworm.
Like fleas, Mosquitoes are less likely to bite healthy animals.
In addition, the healthy animal's own defense system is able to kill off the larvae of
any heartworm that may enter the bloodstream, thus preventing them from reaching
maturity and causing harm.
Factors that will weaken your pet's immune system include frequent vaccination,
commercial pet foods, incorrect diet, stress and even conventional heartworm and
other synthetic medication.
PetAlive Immunity and Liver Tonic
3. Protect and strengthen the heart and circulation system
The adult heartworm lodges in the heart of the animal and a healthy heart and
circulatory system is another measure that you can take to protect your pet.
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Healthy circulation ensures that red blood cells carry sufficient supplies of oxygen
throughout the body to provide vitality, while white blood cells are able to fight
infection.
Diet and exercise play an important role in maintaining a healthy heart and
circulatory system.
PetAlive Heart and Circulation Tonic
4. Regular de-worming in areas with high risk of heartworm
infestation
If you live in a high risk area for heartworm, it is advisable to take precautions and to
have your pet regularly checked - prevention is better than cure.
PetAlive Parasite Dr
Regular use of Parasite Dr will help to:
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Expel and protect against internal parasites like heartworm, roundworm and
tape worm
Restore digestive health after parasitic infection
Calm and soothe the digestive system
Reduce parasite-related problems like restlessness and malnutrition
Cleanse and detox the digestive system and improve digestive functioning
Reduce the symptoms of flatulence, nausea and bloating
Protect against bacterial infection
Reduce yeast overgrowth in the digestive tract
Act as a tonic for the entire digestive system
The importance of temperature:
While the larvae are developing in the mosquito, development continues only when
the temperature is above 64 degrees F.
Further, the temperature MUST remain above 57 degrees Fahrenheit at all times, day
and night during the entire mosquito cycle.
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If at any time during the development into the L3 stage, the temperature drops below
57 F, the development is aborted and must start over.
Remember, it is only the L3 larvae which are capable of infesting your dog.
Now let’s say that a mosquito has bitten an infested dog;
and that the temperature has remained above 57 degrees F for a minimum of 14
days since that bite;
Still, your dog is not infested because the L3 larvae are deposited in a tiny droplet of
mosquito saliva adjacent to the bite, not injected into your dog by the mosquito--as
many would have us believe.
Providing the humidity and temperature are such that the droplet does not evaporate
before they get the chance, the L3 larvae must swim through the saliva and into the
hole left by the mosquito bite, thereby entering your dog’s system.
Once inside your dog, the L3 larvae must spend the next two weeks or so developing
into the L4 larvae.
During this period of time the larvae are living in the subcutaneous tissue just under
the skin, not in the blood of the newly infected dog. The L4 will continue to live and
develop in the subcutaneous tissue for the next two to three months, where they
develop into the L5 stage.
Once they make this development or molt into the L5 or young adult stage, they then
leave the subcutaneous tissue and enter the blood stream.
If the dog is not re-infested with L3 larvae from another bite from another infected
mosquito, the adult heartworm will die of old age in about 2 years.
The microfilaria will also die a natural death unless taken up by a mosquito.
The adult female mosquito, the only one which bites, usually lives little more than
thirty days. Some species live only a couple of weeks.
See, http://www.sci-ctr.edu.sg/ScienceNet/cat_life/cat_zoo03865.html
For a great deal more information on the mosquito visit,
http://www.mosquito.org/mosquito.html
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In his book "Homeopathic Care For Cats and Dogs", under the heading Heartworm,
p332, Dr. Don Hamilton says:
In dogs the "monthly" preventives are effective if given at six week intervals, and
possibly even at seven- or eight week intervals.... The daily preventives are almost a
thing of the past, but these are usually effective given every other day.
On the other hand, Dr Martin Goldstein, in his book, "The Nature Of Animal Healing"
pp, 220, 221, 223, says: "Granted, heartworm is a serious condition... A few caveats
are in order, however. Only a small percentage of dogs who get heartworm die of it,
especially if they're routinely tested twice yearly for early detection. Even in untreated
dogs, after a period of uncomfortable symptoms, the adult worms die... The chances
of a microfilaria-infected mosquito biting your dog the first time are slim. Of it
happening to the same dog twice? Very slim...Early in my career, I saw and treated
hundreds of cases of heartworm disease, most with routine medication, yet witnessed
only three deaths (the last was in 1979). By comparison, we're seeing, cancer kill
dogs on a daily basis. To my mind, the likelihood that toxicity from heartworm pills is
contributing to the tremendous amount of immune suppression now occurring,
especially in cases of liver disease and cancer, is far greater and more immediate
than the threat of the disease they're meant to prevent... As a precaution, I
recommend that all dogs be tested twice a year for heartworm. For clients who insist
on a more active form of prevention, I suggest doses of black walnut given two to
three times a week, as I've actually reversed clinical heartworm with it..."
Obviously two very differing opinions on the safety of the common heartworm
preventive drugs and the efficacy of alternative treatments from two very respected
authors and healers.
Other alternative preventives I've run across are: Soaking an old towel in equal parts
of the essential oils of pennyroyal and citronella; tearing it into pieces and hanging it
in various places around one’s dog runs or property is said to make an excellent
repellent.
Citronella, rose geranium (plumarosa), eucalyptus, pennyroyal, rosemary, rue, and
wormwood are the strongest herbal repellents available, not only for mosquitoes, but
for fleas, and ticks as well. Rubbing fresh leaves of pennyroyal rosemary, eucalyptus,
lavender, and/or wormwood on one’s dog’s coat and/or one’s own skin is also said to
be a good temporary repellent.
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Bulloved Bulldogs:
First line of defense is diet. We include approximately one to two cloves of garlic per
day in everybody's food. Garlic is a natural mosquito repellent;
Safe, natural repellents you can make at home.
Fill a small spray bottle with the following:.
2 drops each, rosemary and lavender oil *
3 drops of citronella oil
20 drops or so of rose geranium (plumarosa) oil
1/2 ounce or one tablespoonful of alcohol based tincture of bay
1/2 ounce or one tablespoonful alcohol based green black-walnut hull tincture
8 ounces of distilled water *
You may, if you prefer, use 3 to 4 drops of one or the other.
This can be sprayed directly on one’s dogs every time they go out, or one’s self for
that matter.
Spraying it on things like lawn or deck furniture can also be very effective. This is a
variation I devised from a recipe included in "The Encyclopedia Of Natural Pet Care,"
by CJ Puotinen
Place approximately one cup of dried calendula (wild marigold) blossoms (available
at most health food stores or herb shops) in a one quart glass container with lid; a
canning jar would be ideal.
Cover with naturally fermented raw apple cider vinegar. Be sure to add enough ACV
that it covers the dried blossoms plus about an additional inch of liquid.
Cover tightly and let stand undisturbed for two weeks. At the end of the two week
period strain the liquid through several layers of cheesecloth.
Rebottle the strained infusion and store in the refrigerator for future use. Don't worry if
there are small particles of the calendula blossoms in the liquid.
When you are ready to use the infusion (when mosquito and tick season arrives) mix
a small quantity of the infused ACV with ten parts of spring water in a spray bottle,
and return the original container of the undiluted calendula-ACV infusion to the
refrigerator for later use.
This final dilution can then be sprayed directly onto your dogs, although I would
recommend avoiding the eyes. They don't seem to getting it in their eyes.
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A 50/50 solution of the original infusion and spring water also works wonders on hotspots and is a good general skin tonic.
The garlic is so effective that we have relatively little use for these final lines of
defense.
Providing one’s dogs are fed a species appropriate raw food diet;
that they are not vaccinated;
they are not treated with flea and tick preventives;
and are not currently being treated with drugs such as antibiotics,
our dogs are at greater risk from the poisons used to kill/prevent heartworms than
they are from any infestation of heartworm. Remember, the best protection against
any infection or infestation is a healthy immune system. If your dog is healthy and has
a truly healthy immune system, even if it is bitten by a mosquito carrying the L3
larvae, it will most likely be able to fight off the invasion without ever developing any
symptoms.
For a quite different view of the subject as well as some interesting additional
information go to http://www.io.com/~tittle/ivc/1996/internet-vet.3.17.html
This parasite is a source of great anxiety among dog caretakers. Thanks in large part to the scare tactics of
many veterinarians in promoting preventive drugs, many people believe that contracting heartworms is the
equivalent of a death sentence for their dogs. This is not true.
I practiced for seven years in the Santa Cruz, California area, and treated many dogs with heartworms. The
only dogs that developed symptoms of heart failure were those that were being vaccinated yearly, eating
commercial dog food, and getting suppressive drug treatment for other symptoms, such as skin problems. My
treatment, at that time, consisted of switching to a natural (that is, homemade) diet, stopping drug treatment
whenever possible, and eliminating any chemical exposure, such as flea and tick poisons. I would usually
prescribe hawthorn tincture as well. None of these dogs ever developed any symptoms of heart failure.
(danger of: vaccines, commercial petfood, and antibiotics)
I concluded from this that it was not the heartworms that caused disease, but the other factors that damaged
the dogs' health to the point that they could no longer compensate for an otherwise tolerable parasite load. It is
not really that different from the common intestinal roundworms, in that most dogs do not show any
symptoms. Only a dog whose health is compromised is unable to tolerate a few worms. Furthermore, a truly
healthy dog would not be susceptible to either type of worm in the first place.
It seems to me that the real problem is that allopathic attitudes have instilled in many of us a fear of
disease, fear of pathogens and parasites, fear of rabies, as if these are evil and malicious entities just waiting to
lay waste to a naive and unprotected public. Disease is not caused by viruses or by bacteria or by heartwormbearing mosquitoes. Disease comes from within, and one aspect of disease can be the susceptibility to various
pathogens. So the best thing to do is to address those susceptibilities on the deepest possible level, so that the
pathogens will no longer be a threat. Most importantly, don't buy into the fear.
That having been said, there are practical considerations of risk versus benefit in considering heartworm
prevention. The risk of a dog contracting heartworms is directly related to geographic location. In heavily
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infested areas the risk is higher, and the prospect of using a preventive drug more justifiable. Whatever you
choose to do, a yearly blood test for heartworm microfilaria is important.
There are basically three choices with regard to heartworm prevention: drugs, nosodes, or nothing. There
are currently a variety of heartworm preventive drugs, most of which are given monthly. I don't like any of
them due to their toxicity, the frequency of side effects, and their tendency to antidote homeopathic remedies.
Incidentally, the once-a-month preventives should be given only every 6 weeks.
The next option is the heartworm nosode. It has the advantage of at least not being a toxic drug. It has been
in use it for over 10 years now, and I am reasonably confident that it is effective. It is certainly very safe. The
biggest problem with the nosode is integrating it with homeopathic treatment. But at least it's less of a
problem than with the drugs.
The last option, and in my opinion the best, is to do nothing. That is to say, do nothing to specifically
prevent heartworm, but rather to minimize the chances of infestation by helping your dog to be healthier, and
thereby less susceptible. This means avoiding those things that are detrimental to health, feeding a high
quality homemade diet, regular exercise, a healthy emotional environment, and, most of all, constitutional
homeopathic treatment. Of course, this will not guarantee that your dog will not get heartworms, but, under
these conditions, even the worst-case scenario isn't so terrible. If your dog were to get heartworms, s/he
shouldn't develop any symptoms as a result. For what it's worth, I never gave my dog any type of heartworm
preventive, even when we lived in the Santa Cruz area where heartworms were very prevalent. I tested him
yearly, and he never had a problem. Visit Dr. Levy's website
Death after Proheart 6 shot the FDA has received more than 4,000 reports of dogs getting sick
after getting a shot of ProHeart 6. And more than 400 dogs have died nationwide.
Pets with a strong immune system may be protected from all sorts of diseases, including heartworm. Read
what Drs. Page, Brown, and Pollaks are saying:
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Dr. Linda Page, N.D. Ph.D. writes that our immune system is our bodyguard. It
works both pro-actively and protectively to shield you from anything in your world that
threatens your life and limb. Our immune system is ever-vigilant, constantly searching
for proteins, called antigens, that don't belong in our body. It can deal with a wide
range of pathogens - viruses, funguses, bacteria and parasites. It can even recognize
potential antigens, such as drugs, pollens, insect venoms and chemicals in foods, and
malignant cells and foreign tissue, such as transplanted organs or transfused blood.
This is also true for our animals. I believe that a strong immune system can protect
animals from heartworm. Read what Dr. Brown and Dr. Pollak says about our animal's
health and immune system - (just below). Shirley
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Dr. Charles W. Brown, DVM - "My colleagues and I have found this product (transfer
factor) to be very effective in modulating the immune system. Transfer factor is a
"soup" of immune-modulating factors, which contains a leukocyte-type molecule that
can passively transfer immunity from one mammal to another by stimulating cellmediated immunity and is antigen specific. Richard Bennett, Ph.D., an Infectious
Disease Microbiologist and Immunologist from the University of California, Davis
School of Veterinary Medicine, believes this could be the most significant development
in animal health care in decades. We have a great number of veterinarians and clients
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who are experiencing very positive results in a broad area of disorders, including
periodontal." more about boosting the immune system with Transfer Factor
Dr. William Pollak D.V.M. - "Recent studies have shown processed foods (cooked
food) to be a factor in increasing numbers of pets suffering from cancer, arthritis,
obesity, dental disease and heart disease, comments Dr Wysong. Dull or unhealthy
coats are a common problem with cats and dogs and poor diet is usually the cause,
according to many veterinarians and breeders. "Dogs, cats and other animals live for
years on foods that come out of bags, cans and boxes. But do these foods promote
health? If they did, our companion animals would enjoy long, happy lives free of
arthritis, hip dysplasia, eye problems, ear problems, fleas and other parasites, gum
disease, lick granulomas, thyroid imbalances, skin and coat problems, personality
disorders, birth defects, breeding problems, diabetes, cancer and other major and
minor illnesses. Before World War II, most North Americans fed their pets raw bones
and table scraps. Today, everyone uses convenience foods, and pet food companies
are industry giants. Diet isn't the only thing that has changed. So has life expectancy,
with the life span of many breeds now less than half what it was two or three decades
ago. Skin and coat problems are so common that we accept them as unavoidable,
and today's vets routinely treat conditions that used to be unusual or even rare."learn
more: The Poisons in Pet Food
Beware of Proheart 6, Heartworm prevention shot
Death after Proheart 6 shot (heartworm drugs)
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Myra lost a perfectly healthy 6 yr old shih tzu after Proheart 6 shot (heartworm
prevention). He started diarrhea and vomiting within 5 days of the Proheart 6, and
over weeks continued digestive problems. Her dog died.
Trouble received the ProHeart 6 shot on 8/20/02 in conjunction with other
vaccinations. He died on 10/17/02 (58 days) after the shot. He was VERY healthy
prior to the shot being given. Danny was a perfectly healthy five-year-old part Golden
Retriever mix who was energetic and happy. He died after receiving Proheart 6. Read
the full testimonials
ProHeart 6 recall - Fort Dodge to Comply with FDA's Request to Recall ProHeart 6
Injectable Heartworm Product from the Market Due to Serious Health Concerns.
Here are just a few of the potential side effects of Proheart:
Swelling and pain at the site of the injection.
Facial swelling
Diahhrea and vomitting
Lethargy and fever
Wobbliness and weakness
Shortness of breath
Erythema multiforme (bodywide disease with a characteristic rash involving the skin and mucous
membranes)
Autoimmune hemolytic anemia (destruction of red blood cells)
Seizures and other neurological events
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Some argue, but . . .
As the co-moderator of an e-mail list on dog health and nutrition, I frequently see
people allege that as long as you have a healthy dog, feed a raw diet, and do not
overvaccinate, your dog will not get heartworms. If only this were true! These
measures may help to some degree, but they are not foolproof. The only way to know
for sure that your dog is protected is to give heartworm preventatives
Some holistic practitioners recommend various herbal or homeopathic preparations
for heartworm prevention, and anecdotal evidence from some dog owners can be
found on many discussion lists devoted to natural dog care.
However, consumers should be aware that none of these alternatives have been
studied for safety or efficacy, nor are there any studies indicating that they are
effective at protecting against heartworm infection.
In addition, some herbal dewormers, such as wormwood and black walnut, are
potentially toxic when used at dosage levels needed to control intestinal parasites
Some holistic practitioners advocate the use of homeopathic nosodes for heartworm
prevention. Again, there are no studies indicating that they are effective
So, how can you reduce your dog's exposure to conventional heartworm
preventative drugs, without decreasing his protection from the nasty
parasite?
First, it is not necessary to give heartworm preventatives year-round in most parts of
the country.
Heartworm development in the mosquito is dependent upon environmental
temperatures.
Heartworm larvae cannot develop to the stage needed to infect dogs until
temperatures have been over 57 degrees Fahrenheit (14 degrees Centigrade),
day and night, for at least one to two weeks.
The amount of time it takes will vary depending on how warm it is: the warmer
the temperatures, the faster the heartworm larvae develop.
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If temperatures drop below that point at any time during the cycle, development
may be prevented, but I wouldn’t rely on this. Temperatures can vary according
to where the mosquito lives, and may be warmer under the eaves of houses or
in other protected areas than the general ambient temperature
Goal is to provide full protection for your dog with minimal drug administration
Mosquitoes may be capable of transmitting heartworm larvae to your dog around two
weeks after your local temperature has stayed above 57 degrees Fahrenheit day and
night.
Give the season’s first dose of preventative four to six weeks after that to destroy any
larvae that infected your dog during that time.
The first dose should be given six to eight weeks after daytime and nighttime
temperatures first exceed 57°F. Continue to give the preventative every four to
six weeks, with the last dose given after temperatures drop below that level on
a regular basis.
Dosage amounts
With at least one drug, you can give your dog less than the recommended dosage of
preventative, without compromising safety.
Milbemycin oxime, the active ingredient in Interceptor, has been approved by
the FDA at one-fifth the regular dosage to kill heartworms only, without
controlling intestinal parasites, including roundworms, whipworms and hookworms.
Novartis has a product, "Safeheart", with this lowered dosage of milbemycin, but has
not yet marketed it. (You can read the FDA approvals showing that milbemycin oxime
will control heartworm at one-fifth the dosage found in Interceptor on the FDA’s web
site
Safeheart contains 2.3 mg of milbemycin oxime for dogs from 2 to 50 pounds,
and 5.75 mg for dogs 50 to 125 pounds.
Interceptor contains 2.3 mg for dogs up to 10 pounds,
and 5.75 mg for dogs 11 to 25 pounds.
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So if your dog weighs more than 50 pounds, you can give the Interceptor for
dogs 11-25 pounds, otherwise you can use the one for dogs up to 10 pounds.
Frequency of preventatives
It may not be necessary to give heartworm preventatives every month. The monthly
dosage schedule was devised to make it easy for people to remember when to
administer the drugs, and to ensure that dogs would still be protected if a dose were
somehow not swallowed or later vomited before being absorbed.
The FDA approvals cite studies showing that Heartgard, Interceptor and
Revolution provide protection beyond 30 days.
If you are very good about remembering to give medications, and you can watch your
dog after administering the pill to be sure that it is not spit out or later vomited, it may
be safe to use heartworm preventatives less frequently than every 30 days. Dosing
your dog every 45 days is a conservative way to stretch your dog's dosage
schedule.
No guarantees
_______________________________________________________________
Wolfcreekranch1.tripod.com
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Volume 1
•
Number 4
•
June 1998
Treating Heartworm Holistically
Veterinarians share conservative and radical alternative approaches.
The veterinary community has invested plenty of research time and money developing effective preventives
and treatments for heartworm, as well as advertising the need to use them. But some holistic veterinarians
worry that man has increased the domestic dog’s vulnerability to the parasite through over-vaccination and
poor foods.
The heartworm goes through a number of astonishing changes in order to complete its life cycle. It must start
out in one dog, get carried away by a mosquito that’s bitten the dog, and return to another dog (through
another mosquito bite) to grow, reproduce, and finish its business in life.
Given the intricacy of the heartworm vector, the difficulty of keeping your dog safe from this insidious killer
is understandable. The most commonly prescribed drugs for heartworm prevention and treatment are fairly
toxic, and capable of causing health complications and even death. Of course, so can heartworms.
Fortunately, when both a disease and its conventional treatments are objectionable, complementary and
alternative medical practitioners can be of tremendous value. As with practitioners who treat humans,
veterinary practitioners offer a range of helpful adjuncts to, and replacements for conventional treatments. For
instance, in the case of heartworm, a conservative adjunctive therapy may consist of herbal and nutritional
support for dogs that are also undergoing conventional drug treatments for heartworm. On the more radical
end of the scale, some holistic practitioners offer a complete alternative to drugs that prevent or treat
heartworm infections.
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A man-made problem?
Whichever end of the scale holistic veterinarians place themselves on, they all agree about the first step
toward heartworm prevention and treatment: A dog must be essentially healthy in order to resist succumbing
to heartworm (or its treatments). This is more than an idle observation – it is the principle that ensures the
survival of wild canines, who suffer far greater exposure to heartworm-carrying mosquitoes but succumb from
the parasites in far lesser numbers than domestic dogs.
“More and more I’m coming to think that heartworm is really a man-made disease,” states Dr. William
Falconer, a veterinarian with a homeopathic practice in Austin, Texas. “The heartworm has been out there
forever as far as we know, but we don’t read reports of wolves and coyotes being wiped out by heartworm,
and yet domestic dogs are falling prey to it. It speaks volumes to what we’re doing wrong in raising these
animals.”
Dr. Falconer, a veterinarian for 18 years (the last 12 with an exclusively holistic practice), thinks it comes
down to three common dog-keeping practices: “We’re vaccinating our dogs too much, we’re feeding them
poorly, and we’re using too many pesticides to kill their fleas. It all helps weaken their immune systems, and
their immunity is really what’s going to save them.” Foxes, coyotes, and wolves, on the other hand, go
unvaccinated, eat only raw meat, bones, and a few plants, and are never exposed to the dozens of toxic
chemicals we use to kill fleas on our dogs and in our homes. Some seem to be able to “fight off” heartworm
infestations; many others host the parasite, but in small enough numbers that the heartworms don’t threaten
their hosts’ lives. That’s nature’s plan for parasites, says Falconer.
“Parasites were never intended to kill their hosts. Something is very out of balance when that happens. A
parasite’s whole evolutionary thrust is to continue its life cycle; if it kills its host, there’s a dead end. The fact
that our domestic dogs are dying of this disease in greater and greater numbers indicates that something is
way out of whack,” Falconer says. Holistic veterinarian Dr. Carolyn Blakey, of Westside Animal Clinic in
Richmond, Indiana, concurs with that view, and adds another concern.
“A really healthy animal won’t get parasites that overwhelm them, but there are so few really healthy dogs out
there. On the other hand, insects are getting stronger every day, due to their rapid adaptation to our heavy use
of insecticides. We may be getting superparasites because of our reliance on insecticides.”
Given the wild canines’ efficiency in dealing with heartworm, both of these veterinarians, and virtually all
other holistic practitioners, recommend utilizing as many aspects of the wild canines’ lifestyle as is practical
for domestic dogs, including, most importantly, a natural diet of raw meat, bones, and some plants, minimal
vaccination, and severely curtailed exposure to flea-killing pesticides. “Animals who are healthy are not in
need of a specific preventive; their lifestyle is their preventative,” Falconer asserts.
Immune defenses
Researchers have noted that a certain percentage of domestic dogs are able to mount a decent defense against
heartworm. They’ve seen dogs whose immune systems are able to seek out and destroy heartworm
microfilariae in their blood. They’ve also observed dogs who outlive their heartworm population with no
appreciable symptoms of heartworm disease. Scientists speculate that when these dogs were originally
infected with heartworm larvae, their bodies organized an immunological defense against new larval attacks,
and though a few larvae were able to develop into adult heartworms, no further infestation could occur.
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This line of thought is behind the research by a company called Wyoming DnaVaccine, into a heartworm
“vaccine.” The company hopes to develop a vaccine that would trigger the dog’s body to produce an
antibody-based immune response that would wipe out heartworm larvae. While Wyoming DnaVaccine
researchers claim to have developed products that use this approach to successfully vaccinate dogs against
other parasites such as hookworm, pinworm, whipworm, and roundworm, the complexity of the heartworm
life cycle has proven to make development of this product more difficult.
Dr. Carolyn Blakey uses an herbal extract, a homeopathic
remedy and nutritional supple-ments to battle against heartworm disease.
Homeopathic approach
Dr. Falconer uses homeopathy to accomplish the same ends as this high-tech approach. He seeks to boost the
dog’s level of health and immune readiness with homeopathic remedies custom-prescribed for each
individual. This is accomplished by conducting a thorough intake of the dog’s health history and lifestyle.
Then the dog is given the remedy, and the owner is asked to closely observe the dog for a few weeks.
Sometimes, the symptoms indicate the need for another remedy, and the procedure is repeated.
This protocol is known as the “classical method of homeopathy,” explains Dr. Falconer. “I choose one remedy
chosen on the totality of symptoms the dog is showing, and then carefully evaluate the dog after two or three
weeks have gone by, to see how the symptoms are doing. Sometimes I may have to switch remedies, but each
remedy is followed by an evaluation period.”
Falconer says he has had almost perfect success with his clients’ heartworm cases, using nothing but
homeopathy and healthy dog-keeping practices. “I’ve gotten to the point now where I am very confident
treating heartworm. If someone calls and says they have a heartworm positive dog, I tell them not to panic; the
prognosis is good,” he says. His only failure came with a very old, weak dog with a very bad heartworm
infection and advanced symptoms of heartworm disease, including a constant cough.
Homeopathy does not offer an overnight cure, says Falconer, but it is effective. “It takes three to six months,
but what I’m doing is making the dog healthy; that takes time,” he explains. “Once they are healthy, they
throw off the heartworm just like they should, just like the wolves, foxes, and coyotes have been doing for
generations.”
Falconer supports the homeopathy with good dog-keeping practices. As mentioned above, he suggests the dog
be kept from immune-compromising vaccines and chemicals. And he recommends a healthier diet, based on
recipes utilizing raw meat and whole foods. He also recommends supplementation with vitamin C, and might
also suggest vitamin E supplements if there is evidence of a heart problem. While he believes these
supplements can be very helpful, he’s cautious about making the dog’s treatment regimen too complex for the
owner. “I like to keep it simple so that people do it. If it’s too complicated, it will be too hard for the average
person to get it done,” he says.
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While Falconer says he is willing to work with clients who are interested in the benefits of homeopathy, but
who also want to give their dogs traditional heartworm preventives or treatments, he’s less enthusiastic about
this approach. “Homeopathy can help these dogs, but it’s picking up the pieces. The drugs kill the worms, but
you’re still left with a dog that’s in poor health. We know he was in poor health because he got the
heartworms in the first place; now he’s even worse off because of the assault on his entire system. So we have
to rebuild this dog’s health from the ground up,” he says.
Supporting the heart
Dr. Blakey, a veterinarian for 31 years, the last three spent in an all-holistic practice, takes a very different
approach to treating heartworm-positive dogs. She has clients who use traditional drugs and others who take a
completely alternative approach to prevention and treatment, and has seen success with both approaches. The
secret to her success, she says, is attributable to the homeopathic and herbal remedies and nutritional
supplements she administers to improve the dogs’ circulatory function.
Dr. Nancy Scanlan uses a variety of natural products to support the dog’s efforts to clear toxins – including
conventional medications and dead worms – from his system.
“Heart support is as important, if not more important, than killing all the worms,” Blakey says. “As long as
the heart is strong and capable of working thorough the challenges presented by the worms and the dog’s
overall health is good, he will be able to outlive his wormy burden, or survive the conventional drug
treatment, whichever route the owner chooses to take.”
Blakey’s treatment is multi-pronged, and includes an herbal treatment of black walnut to weaken or even kill
the heartworms, homeopathic support of Arsenicum album for the heart energy, and a nutritional supplement
for supporting the heart function.
Blakey’s two favorite nutritional supplements for the heart are CoQ10 and CardioPlus. CoQ10 is an antioxidant and an enzyme that seems to offer special benefits to the circulatory system. The body can produce
the enzyme, but people and dogs seem to produce less of it as they age. Supplementation with the enzyme has
been credited with lowering blood cholesterol levels and preventing heart attack and stroke. The other
supplement is Quantum Inc.’s CardioPlus, which contains CoQ10, as well as a number of other nutrients
thought to be beneficial for the heart.
Perhaps most exciting is the black walnut treatment, which Blakey swears is capable of killing adult
heartworms. “It often, but doesn’t always kill the adults, but it weakens them considerably,” says Blakey. The
herbal treatment’s effect on the worms, and subsequent improvement in their host, is astonishing, says Blakey.
22
“It’s incredible. The dogs start feeling better within days, because their circulation is improved and their heart
can function better.”
Veterinary assistance is important
While the herbal extract Blakey uses is commonly available in health food stores, Blakey maintains that dog
owners must work with a holistic veterinarian when planning and executing the treatment protocol. The
veterinarian will adjust the dog’s dosage of the extract according to his weight and condition. The extract
comes in a liquid that the owner can squirt into the dog’s mouth daily for about 30 days. The dose is reduced
if the dog experiences nausea.
When Blakey uses this treatment protocol, she rechecks the dog at this point, performing a heartworm antigen
test to determine whether heartworms are still present. If they are, she will sometimes recommend treatment
with the black walnut for another two to three weeks. After that, she says, the herbal extract will have
accomplished as much as it can.
If the dog still has heartworms, the dog’s owner has another decision to make: they can decline further
treatment and just “get on with the dog’s life,” or go ahead with the conventional treatment with Immiticide to
kill the remaining adults. For her part, Blakey feels good about either choice. “Left untreated, many of the
adult heartworms will just die out – the black walnut can weaken them that substantially. Or an owner can go
ahead with Immiticide; I feel fine about it at that point. After the black walnut treatment, a dog is really ready
for the Immiticide; he’s not wiped out, and he can handle the Immiticide much better.”
The black walnut doesn’t seem to affect the microfilariae, but Blakey says they can be wiped out with a dose
of Ivermectin later on, once the dog is feeling better. The dog’s improved health will help him cope with the
Ivermectin, too.
Homeopathic preventive
In addition to her treatments for infected dogs, Dr. Blakey also has an alternative for dog owners who prefer
not to use any of the preventive drugs at all. “Some dogs have had bad single reactions to the preventives;
others have poor liver function, making it difficult for them to clear the toxins from their system every time
the drugs are administered,” explains Blakey.
For these dogs, Blakey recommends the use of homeopathic nosodes for heartworm. Nosodes are prepared in
the same fashion as other homeopathic remedies. The active ingredient substance is super-diluted, and then
shaken vigorously or “potentized,” following dilution, a process which is thought to transfer the medicine’s
healing properties to the water.
Most homeopathic remedies consist of plant, mineral, or animal products that are intended to emulate the first,
tiny symptoms of a disease, thus triggering the body to mount an offense against the unwanted condition.
Nosodes differ in that they are made from a product of the disease, such as pus, or infected blood, that is so
diluted that no more of the substance exists. Homeopaths explain that the “energy” of the disease is still
present in the nosode preparation, and, properly administered, the nosode will trigger the body to produce an
23
immune response intended to battle the invader. In this case, the heartworm nosode is intended to trigger the
dog to produce antibodies that are capable of destroying the larval form of the heartworm.
No studies have ever been conducted on the efficacy of this approach for preventing heartworm infestation,
but Blakey claims that she and other homeopathic veterinarians have seen success with it. She cautions dog
owners who want to use these methods that they had better be committed to backing up this approach with
other immune-system builders such as the best diet, and avoidance of unnecessary vaccines and pesticides.
Conservative approach
California veterinarian Nancy Scanlan says that while she agrees in theory with the idea that a person can
prevent their dog from getting heartworms by keeping their immune system ship-shape, she doesn’t know of
anyone who cares to test the theory on their own dogs. Dr. Scanlan, who has been in veterinary practice for 27
years (the last 10 with an all-holistic practice) characterizes the holistic treatments she recommends for
owners concerned about heartworm as “complementary,” rather than “alternative.”
That doesn’t mean she sees this role as less than valuable. Though the preventive and treatment drugs can
save dogs’ lives, she says, they can and do have serious effects on dogs’ health. That’s where holistic
treatments can really shine, says Scanlan.
First, Dr. Scanlan recommends using the homeopathic remedy called Thuja 6C to help the dog clear his
system of toxins, on the day of, and two days following treatment with the monthly preventive drugs.
A big fan of daily antioxidant use, Dr. Scanlan regards the use of antioxidants before and after giving the dog
(especially older dogs) preventive drugs as absolutely critical. “Supplementation with vitamin E and C are the
absolute minimum in this application,” says Scanlan. “The older the dog is, the more likely it is that I will also
prescribe supplementation with superoxide dismutase (SOD, an antioxidant used by the body to counteract
harmful free radicals), CoQ10 (an enzyme that has been shown to improve heart and circulatory function),
and Pycnogenol (a powerful antioxidant derived from the bark of the French Maritime Pine Tree). These
substances help the dog decrease inflammation, and help the liver process toxins and waste products.”
Because vitamin E is a fat-soluble substance, and can cause side effects in doses higher than the maximum
amount suggested, Dr. Scanlan advises that dog owners check the total amount of vitamin E a dog receives
from his food and other supplements. She recommends the dog receive between 100-400 IUs of vitamin E per
day, depending on their size (100 IUs for small dogs, 400 for large dogs).
Vitamin C, on the other hand, can be given to the dog in whatever amounts his bowels will tolerate (diarrhea
will occur if the dosage gets too high). For dogs receiving heartworm preventive drugs, she recommends
giving them 250 mg to 2,000 mg twice a day, depending on their weight. She prefers the Ester C vitamin C
products, except for dogs who have overly alkaline urine; those dogs are better off with the ascorbic acid
forms of the vitamin.
Help with Immiticide
IIf a dog has tested positive for heartworms and the owner wishes to treat him with Immiticide, the safest and
most effective drug for killing the adult heartworm, Scanlan recommends the use of nutritional supports to
help the liver accomplish the huge task of ridding the dead, toxic worms from the body. She prescribes the
24
Silymarin marianum (milk thistle), an herb with a long history of use for liver ailments. Her favorite source of
the herb is a product called Oxygenics, which also contains minerals that assist liver function. Depending on
the dog’s size, she would administer 1/4 to one tablet per day for the duration of the time the dog is
recuperating from the Immiticide treatment.
A lesser-known nutritional supplement to help the dog’s liver is raw, fresh beef liver. Scanlan recommends
giving the dog a small piece of fresh liver (one tablespoon for big dogs, one to two teaspoons for smaller
dogs) each day while he is dealing with the aftereffects of Immiticide treatment, and for at least 30 days
afterward.
There has been some discussion among dog owners about the use of an herbal supplement called Paraway
made by Enrich Corp. It contains black walnut, as well as a number of other herbs commonly used against
intestinal parasites. These herbs include pumpkin seed, wormwood, clove, sage, garlic, and more. While the
product is intended for treating parasitic organisms in humans, some dog owners have tried giving it to their
dogs for heartworm infestations. “I’ve never heard of anyone having success with Paraway for heartworms,”
says Dr. Scanlan, adding, “It’s really aimed at parasites that live in the gastrointestinal tract; there is no reason
to believe it could kill worms living in the cardiovascular system.”
Modified treatment
If a dog owner is uncomfortable using any of the above therapies as an alternative to, or an adjunct for,
traditional treatment, Dr. Blakey and Dr. Scanlan suggest a number of ways that the conventional treatments
can be modified to make them gentler.
If a dog who is hosting heartworms has proved to be sensitive and reactive to medications, if his health is
poor, or if he is carrying a particularly high heartworm burden, his veterinarian may choose a modified
Immiticide treatment.
The usual protocol (described fully in WDJ, May 1998) is two injections of the drug, delivered
intramuscularly 24 hours apart. The first injection generally kills the weaker worms, and the rest of the
population in killed with the second injection. The success of this regimen depends upon the dog’s ability to
absorb and “shed” all of the dead worms within a fairly short period of time.
In the modified treatment, a single injection is given to the dog, and he is given four to six weeks to recover
before further treatment. In most cases, a veterinarian will run a blood test to make sure that the dog’s liver is
functioning properly following the tremendous challenge posed by the disposal of the first batch of dead
worms. If the test indicates the liver is functioning well, the veterinarian will proceed with the standard
regimen of two doses, 24 hours apart.
Stretching the preventive
Modifications may also be made to the traditional preventative regimen. Unlike the conventional treatment
protocol, where only one acceptable drug (Immiticide) is available, dog owners can choose between three
conventional preventatives. Fewest side effects have been reported from use of Diethylcarbamazine (DEC),
the drug that has been on the market the longest, and this is the choice of many owners of chemically sensitive
dogs. Much less convenient to the owner than the other drugs, DEC must be administered every day, and must
not be given to any dog that may have circulating microfilariae.
25
Both Blakey and Scanlan point out that the treatment regimen of both Ivermectin (found in the preventive
HeartGard-30) and milbemycin oxime (found in Interceptor and Sentinel) can be safely reduced to lessen the
dog’s exposure to the drugs.
The labels of both drugs indicate that for optimum safety, they should be given to the dog every 30 days
during the mosquito season. Since both drugs kill all migrating heartworm larvae, and the larvae take 50-70
days to travel from the site of their carrier mosquito’s bite to the circulatory system, theoretically, if the drugs
were administered only every 45-50 days, the dog would still be protected. If taking this approach, however,
an owner must be organized, since the safety window will be very small.
Be proactive
No matter which approach dog owners decide to take to prevent or treat their dogs for heartworms, all the
holistic practitioners consulted agreed on two key issues:
• Use the traditional approach, the alternative approach, or a combination of the two, but use something.
Heartworm disease is frightening and serious, and it mustn’t be ignored.
• Testing your dog for heartworm, utilizing the tests for microfilariae and adult heartworms, should be done at
least once each year. That recommendation might be stepped up to twice a year if a person is using only
alternative methods to prevent heartworm infection. The sooner an infection is treated, the better.
-By Nancy Kerns
Thanks to Nancy Scanlan, DVM, of Sherman Oaks, CA, William Falconer, DVM, of Austin TX, and Carolyn
Blakey, DVM, of Richmond, IN for their help with this article.
Resources:
American Heartworm Society http://www.heartwormsociety.org
Mosquito.org
Io.com
Holistcanine.org
Shirleys-wellness-café.com
Whole Dog Journal. Mary Straus, March 2006
Treating Heartworm Holistically. Whole-Dog-Journal. Volume 1 – Number 4 – June 1998
Homeopathic Care for Cats and Dogs. Don Hamilton
Emerging Therapies: Using Herbs and Nutraceuticals in Small Animals (AAHA Press, 1999)
Dr. Susan Wynn
FDA Center for Veterinary Medicine FOI Summaries:
http://www.fda.gov/cvm/FOI/foidocs.htm
See Section 1, NADA 138-412 for Heartgard, and Section 2, NADA 140-915 for Safeheart and
Interceptor, and NADA 141-152 for Revolution.
Timing Heartworm Preventatives
http://www.citadeltm.com/Heartworm.html
26
Heartworm Prevention
http://www.veterinarypartner.com/Content.plx?A=595
Adverse Reactions
http://www.dogsadversereactions.com/
Wolfcreekranch1.tripod.com
Naturalrearing.com
The Holistic Animal – Char Raby – 517.529.9073 – charjackr@sbcglobal.net
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