Heartworms?

[GinaG]

Hi
I have just read a (SAD) post about someones dog dying from Heartworms and the fact that he hadn't been giving the medication monthly. This may sound naive but do all Rottweilers need to have this medicine regularly? We live in New Zealand and no-one including our vet has mentioned this. Our little girl is 3 mths old and I want to take all the necessary precautions to protect her health.
Your advice please

[HerculesMomma]

If you get mosquetos (sorry, I know I killed the spelling on that one) then it's soemthing you should be looking into for your dog. I'm not sure at what age they start the heartworm preventative medicine for dogs, but I would surely ask your vet about it.

The treatment for a dog with heartworms if very painful for the dog if I understand correctly. If the heartworms go undetected for too long, then the dog could die from them and/or have a much harder time being treated to rid the heartworms from their system. I believe they have different methods now for the preventative. I think one is a shot you get at the vet every few months, the one I'm using is just a heartworm chewable pill (Hercules loves the taste too!) that you give once a month at the same time every month. My cousin only does heartworm chewables in the warm months where I live as the winter time it gets very cold. I give them to Hercules all year round as when I adopted him he had already had heartworms, so there is no way I'll risk him getting them again.

Hope this helps some.

[Judi W]

Don't know if New Zealand has heartworm. Every place in N. American is subject to heartworm and preventitive meds are recommended for all dogs, not just Rottweilers. Do a bit of research to see if they occur in New Zealand and then query your vet. Mick might know as the proximity of NZ and Australia would probably make them similar.

[Squeaky2004]

Originally Posted by HerculesMomma

I'm not sure at what age they start the heartworm preventative medicine for dogs, but I would surely ask your vet about it.

My vet had Squeak on Interceptor last month (she was 4 months old) and one pill to be given to her on the First of every month until November I don't know if there is certain criteria or not that they have to reach first I just got it lol.

[Judi W]

Well, in brief..............

"Heartworm disease is present on every continent except Antarctica"

Imports are screened for the disease.
The vector is the mosquito, so most likely if you have mosquitos, you have heartworm. Murial sells heartguard in NZ so I presume there is a need for it. Talk to your vet and inquire. Starting at about 4 months is the usual and I believe most of us use the product year round. It also protects against many (not all) internal parasites.

[dolphin]

I use heartguard every month on the same day all year long. Why take any chances its worth getting. :)

[chivas]

Just an FYI for those of us who have alot of dogs of different sizes and spend a fortune on heartworm preventative. You can actually give it every 6 weeks ( i have been doing this for years). It is sold to be given monthly as it is assumed it is easier to remember every month, but several vets i worked with and the sales rep for Heartgard told me that it can be given every 6 weeks, so Ive done it that way for 12 years on 5 different dogs and never had a problem.
Kim

[Karlan]

Originally Posted by chivas

Just an FYI for those of us who have alot of dogs of different sizes and spend a fortune on heartworm preventative. You can actually give it every 6 weeks ( i have been doing this for years). It is sold to be given monthly as it is assumed it is easier to remember every month, but several vets i worked with and the sales rep for Heartgard told me that it can be given every 6 weeks, so Ive done it that way for 12 years on 5 different dogs and never had a problem.
Kim

That is interesting.. Thanks for the info!

[Lorrie]

Having 4 heartworm dogs come thru rescue in the past year I have done a lot of research into the topic as it is not common here in Ontario.

Here are some interesting stats.

HEARTWORM 2002 Survey Facts

Problem: Heartworm infection has been reported in dogs in all 50 states. Of the dogs tested in 2001, at least 240,000 were positive for heartworms.
Causes: A June 2001 Gallup study found that about half the dogs in the U.S. were given a heartworm preventive. Of the dogs that were on prevention, the average number of monthly doses administered was half the number recommended by veterinarians.
1. Key Point: Fifty-five percent of dog owning households were on some form of heartworm preventive, down from a high of 66% in 1998
2. 151.5 million heartworm preventive doses were dispensed (prescribed) by veterinarians in 2001
3. Most veterinarians recommend year round prevention.
4. Of the dogs on prevention, the average doses dispensed was 5.4 per year
5. There is an average compliance gap of 5 months.
In January 2002, Merial (the makers of HEARTGARD® Plus (ivermectin/pyrantel) and HEARTGARD® (ivermectin) for Cats) partnered with the American Heartworm Society to survey veterinary clinics and determine the incidence of heartworm infection by state and county in the U.S. (*Incidence = number of new cases occurring during a certain time.)
In the survey, 18,000 veterinary clinics reported 244,000 positive heartworm tests in dogs and 3,095 in cats in 2001. Over 27 million dogs in the U.S. are not on a heartworm preventive and may not have been tested. Therefore, the incidence in the U.S. is likely much higher than indicated.

Top 10 Reporting
Heartworm States

# of Positive Dogs # of Positive Cats % of Clinics Reporting Per State

1. Texas 38,535 362 64%
2. Florida 29,749 743 78%
3. Louisiana 18,700 158 74%
4. North Carolina 17,338 200 79%
5. Georgia 13,896 133 64%
6. Mississippi 11,522 107 73%
7. Tennessee 10,324 39 92%
8. South Carolina 9,387 131 79%
9. Alabama 9,308 95 83%
10. Indiana 8,348 107 73%

HEARTWORM DISEASE
Mosquitoes feeding upon an infected dog take up a number of these microfilariae with the blood meal. The freshly acquired microfilariae migrate from the digestive tract of the mosquito to the abdominal region where they undergo a transformation. Within 2 or 3 weeks they reach the infective stage. At this time the larvae are actually miniature adults that are small enough to live within a mosquito. Development in the mosquito is temperature dependent, requiring approximately two weeks of temperature at or above 80 degrees F. Below a threshold temperature of 57 degrees F, development cannot occur, and the cycle will be halted. As a result, transmission is limited to warm months, and duration of the transmission season varies geographically.
Next, they break into the body cavity of the mosquito and migrate to the mouthparts. By this time the mosquito is ready for its second blood meal. As the mosquito feeds upon its host, the infective larvae are deposited on the skin. The heartworm larvae undertake extensive migration through the tissues beneath the skin, which continues for some 60-90 days until they molt and become immature adults. The immature adult heartworms migrate to the right side of the dog's heart within a few days of their final molt, presumably carried by the venous circulation. Worms that enter hosts other than canines generally die within several days.
Final maturation and mating occur in the pulmonary arteries. The adult worms live in the right side of the heart and pulmonary arteries, where they may survive for up to seven years. Production of microfilaria by fertilized female worms begins approximately six and a half months after infection. Microfilaria are then released into the circulation, for a mosquito to ingest during a subsequent blood meal.

HEARTWORM DISEASE - Other Testing
The chief issue in the diagnosis of heartworm disease centers around the detection of heartworm infection. The following are a list of diagnostic methods that have been and are used in the detection of heartworms within the pet dog's body.

BECAUSE OF THE FIVE MONTH MINIMUM MIGRATION TIME OF THE LARVAL HEARTWORM AFTER INFECTION, IT IS OF NO USE TO HEARTWORM TEST DOGS YOUNGER THAN FIVE MONTHS OF AGE. THESE PUPPIES ARE
TOO YOUNG TO BE INFECTED UNDER ANY CIRCUMSTANCES.

DIRECT BLOOD SMEAR
While this method is a simple screening test, it is not recommended as a regular test method. In this test, a single drop of blood is examined under the microscope for the presence of live microfilariae. If a large number of microfilariae are present, chances are at least one will be seen seen swimming by. Of course, detection of heartworm larvae in this way require large numbers of larvae for detection (less than 20-50 microfilariae per ml of blood will not be detected). More subtle infections will be missed.
DIFIL TEST AND KNOTT'S TEST
These tests represent "concentration" methods for the detection of microfilariae so that more subtle infections can be detected. In these tests, a larger amount of blood is either centrifuged or filtered to concentrate any microfilariae present. When a microfilaria test is to be done, either of these would be appropriate. Nowadays, microfilaria testing is usually done in conjunction with antigen testing (see below).
DIPETALONEMA RECONDITUM: THE OTHER MICROFILARIA
Heartworm is not the only species of worm that has circulating microfilariae as a first stage larva. There is another parasite called Dipetalonema reconditum, which is transmitted by fleas, which may be picked up by the microfilaria tests. Subtle differences in the swimming characteristics, nose structure, and tail structure can be used to distinguish this harmless larva from the more serious heartworm microfilaria. Before immunotechnology, there was an element of diagnostic challenge when microfilaria were detected in the blood (was the nose the shape that would justify a harsh and possibly life-threatening treatment for heartworm infection or was it a harmless creature for which no treatment was needed?) The advent of antigen testing has made this distinction much easier to make.
ANTIGEN TESTING
Using genetic engineering, it has become possible to create extremely sensitive tests capable of detecting tiny pieces of adult heartworm skin circulating in the blood. In this way, very small numbers of adult worms can be detected, even single worm infections. This kind of testing has made it possible to detect infections in which no microfilariae are present: the so-called "Occult Infections." Most of these immunological tests are available as test kits which can be performed in the veterinarian's office while you wait.

There are many important reasons why a dog might be infected with adult heartworms yet no microfilariae can be detected:
* Single sex infections or single worm infections
Younger female worms tend to be resistant to the drugs used to clear adult worms. This means that after the first treatment with anti-heartworm medication, a group of young female worms will be left. If antigen testing is not performed, one could be misled into thinking that the infection had been completely cleared.
* Immunologic destruction of microfilariae
In the cat, the period in which microfilariae can be detected in the blood stream is extremely short as the immune system rapidly groups and clears these larval worms.
* The dog is taking heartworm prevention medication
Both Interceptor and Heartgard30 are able to kill circulating microfilariae (but not adult heartworms). If for some reason, a dog is not properly tested and has missed a dose of medication, it is possible for an infection to establish yet no microfilariae will be detected. People commonly ask why they must continue annual testing in animals that are on preventive medication; this is one reason.
Since Dipetalonema microfilariae can be mistaken for heartworm larvae and since microfilariae can be transferred to unborn puppies (but adult heartworms cannot), it is felt by many specialists that no microfilaria positive dog should be treated for heartworm without a positive antigen test.
ANTIBODY TESTING
Antigen tests have limited usefulness when it comes to infections involving only a few worms. One problem is that the antigens detected by antigen tests are unique to female worms. For most tests, at least three female worms are needed for the test to show a positive result. Animals infected with only male worms will test antigen negative. To get around these limitations, antibody tests have been developed to detect the host's immune response against the parasite. This kind of breakthrough has been especially important in testing for cats in whom infection with one or two worms is the usual situation. Antibody testing may be able to detect infection sooner than can antigen testing and infections involving only male worms can be readily detected.

I use plain old HeartGuard (not the Plus) it is systemic for the
24 hour period that the ivermectin is in the bloodstream. That's ALL. Not 30 days like many of the other products. All it does is kill the microfilaria in the bloodstream (the baby heartworm if you will). I would give it every 45 days during mosquito season. I also give them each a capsule of milk thistle (containing 175mg silymarin) every day for 3-5 days beginning the day I administer the HW preventative. Milk thistle will naturally detox the liver and I use it after surgeries, vaccinations or once every couple months just because!

[VON KIRCHER]

What age should this be started? Are there any side effects? What is a good med? We live here in California, and mosquitos are not a huge problem, but I don't want to risk it...

[groupieindenial]

My pup took his first med for HW at 8 weeks. The vet said their never really too young to take it. If you wait any longer, well into the summer, you may be required to to do a preliminary test first. I decided to just start giving it to him, save $ on the test. I have never known anyone's dog to get HW, and the vet said the same thing, its rare. But I think its rare only because many many dogs are on the preventative medication, lowering the perplexity of it spreading. Look how fast west nile spread accross the continent? Only 2 years. I think if people stop giving their dogs HW meds, the epidemic would resurface.

[GinaG]

Thanks for all the advice. Its winter now so there are no mosquitos around, I asked a friend of ours last night if he fed his Rotti HW meds and he said no he never had. Next time I go to the vet I will enquire if it is a problem here in our town or in NZ and go from there. Now just have to work on how to stop her chasing my cat and eating the cats biscuits!

[Anne]

I am in Australia and there is definitely heartworm here. I imagint this would also be the case in NZ.

My dogs are on a monthly dose of Sentinel Spectrum. It does heartworm, fleas and all intestinal worms including tapeworm.

[Lorrie]

Originally Posted by groupieindenial

My pup took his first med for HW at 8 weeks. The vet said their never really too young to take it.

I would be changing vets!!! And you are in Ontario ... Unbelievable! I could maybe understand it a bit more in an area where HW was prevalent. Guess the vet feels it is never to young to start poisoning a immature immune system with unnecessary toxins.

Originally Posted by groupieindenial

I decided to just start giving it to him, save $ on the test.

The blood test is something like $40 dollars .. (which equal $10 US ) not a lot of money compared to your puppies health.

The typical age to start HW preventative is around 4-6 month.

[Dominey]

We don't treat for HW here in Scotland - but we don't have any mosquito's, only midges!
The vets here recommend treating for HW if you are going to take your dog overseas (and I think it s requirement for pet passport as well)
I found this report on the internet...
http://www.maf.govt.nz/biosecurity/p...ia-immitis.htm
seems like it might not be a big risk in NZ? This is probably why yor vet didn't recommend it.