Heartworm scare

I'm sharing this with all of you, in the hopes that someone will "see the light" as I did today.
I know heartworm is out there, I know its terrible, I know its preventable. My parents did not treat any of the dogs we had, no one I knew growing up had any issues, I've never known anyone (other then over the internet) with a dog that had heartworm. No first hand experience with it.
I've been a slaker, my dogs would get their pills, then not, then remember to give one, then go a few months without...
Thursday night a girlfriend called to tell me that one of her dogs tested positive . Friday morning I called my vet. I have been sick to my stomach since Thursday night, could barely think about anything else. Kept going over in my head all the rescues that I've seen you all take in with Heartworm, the terrible treatments. How strong would my dogs be? Lucy is starting to age, could she handle it? How could I be so neglectful of my precious crew? I buy them good food, watch their weight, new toys, new beds, etc. Why was I not doing this one easy thing?!
Today all three went in, all three were tested, all three were NEGATIVE! I left with 6 months of pills for each dog. They got their pills wrapped up in roast beef as soon as we got in the door. There is a reminder on my phone, stickers are on the calender, the boys and I had a very serious talk about helping us all remember on the 20th of each month.

Thank you pug gods for keeping my babies safe.
Please, please, please, if you don't do it regularly get your dogs tested and on a med routine. I don't know what I would've done if...

Heartworm is a very scary thing. Your friend's dog has my thoughts.

And don't be hard on yourself. You're already doing more for your dogs than many people do when it comes to heartworm. It's so easily (and pretty cheapily) prevented, and yet we have so many clients who just don't listen when it comes to HW.

Not to scare you as I am sure your dogs are fine and won't test positive, but it takes heartworm 7 months to grow to "adulthood". Only at the age of 7 months will heartworm show up positive on a test. Most people test yearly, but you may want to consider testing again in 7 months instead of 12. Like I said, I'm sure your dogs are fine, but just a consideration. Also, as I'm sure you will, it doesn't hurt to protect through winter. Mosquitoes transmit heartworm, but it still doesn't hurt to protected yr round (and again, it's not generally expensive!).

So glad your kids are okay and I'm glad you're enlisting the boys to help protect the pups!! Just think, you're keeping the dogs healthy and teaching your kids how to be good future dog owners as well!!

These are the types of lessons we all need sometimes. Don't beat yourself up. I'm glad you got the reminder, and your babies are okay.

WOW Sarah, that must have been such a huge scare !!!!
This is a great warning for new and even old pug owners. YAY for the negative results
I will keep your friend & her pugger in my thoughts & prayers

Alls well that ends well but you can never remind people enough!

Heartworm really frightens me. A neighbor adopted a Frenchie from a puppy mill rescue operation (out of Missouri, if I recall correctly) and the dog had heartworm. She came through the treatment OK, but she was young and able to deal with it. I know we were all so concerned while it was going on.

Glad your pugs checked out OK.

If you have trouble remembering, you may want to give the pills on a day that you do something else each month. For me, the 1st is best. I can remember when the month changes, I give the pills. I also get paid and pay all the bills then too.

I'm so glad everyone tested negative! Unfortunately, a scare close to home is what we need sometimes. I hope your friend's dog comes through treatment ok.

I had to lecture my MIL not too long ago as she had been neglecting giving her shihtzu his heartworm meds. Hopefully she will continue being diligent about it.

I love the fact that I can share without being blasted. Love you all!! I know that if I'm an idiot, then its likely there are others like me out there. I keep looking at my crew and just breathing a huge sigh of relief

My girlfriends dog tested positive, but apparently its not too far progressed. So they'll give her Heartguard once a month for 6 (?) months, which should weaken the worms. Then proceed to the next step. The vet said she's a very healthy dog so that's encouraging. I appreciate all the good thoughts for her.

I think that heartworms are a relatively recent problem and I know they started in the south and are slowly moving northward, there's even been a dog that tested positive in Alaska (thought he may have been bitten in the Lower 48) so I think that's why people didn't worry about heartworms years ago.

I'm glad all your babies are heartworm negative. I know it makes it easy for me to remember to give them on the same day every month. Mine get theirs on the 15th. I also know of people who stop giving preventative after the first frost because all the mosquitoes are supposed to be killed by a frost, but I'm not that trusting. Insects are tough critters and I've heard of dogs getting infected after a frost too.

The treatments aren't as bad as they used to be but they're still pretty expensive, this is definitely one of those ounce of prevention things!

pugasaurus wrote:I think that heartworms are a relatively recent problem and I know they started in the south and are slowly moving northward, there's even been a dog that tested positive in Alaska (thought he may have been bitten in the Lower 48) so I think that's why people didn't worry about heartworms years ago.

I'm glad all your babies are heartworm negative. I know it makes it easy for me to remember to give them on the same day every month. Mine get theirs on the 15th. I also know of people who stop giving preventative after the first frost because all the mosquitoes are supposed to be killed by a frost, but I'm not that trusting. Insects are tough critters and I've heard of dogs getting infected after a frost too.

The treatments aren't as bad as they used to be but they're still pretty expensive, this is definitely one of those ounce of prevention things!

I have always given year round even when I lived in Illinois because the heartworm meds that I use also protect against other parasites.

leslyeb wrote:I know it makes it easy for me to remember to give them on the same day every month. Mine get theirs on the 15th. I also know of people who stop giving preventative after the first frost because all the mosquitoes are supposed to be killed by a frost, but I'm not that trusting. Insects are tough critters and I've heard of dogs getting infected after a frost too.

The treatments aren't as bad as they used to be but they're still pretty expensive, this is definitely one of those ounce of prevention things!

I have always given year round even when I lived in Illinois because the heartworm meds that I use also protect against other parasites. [/quote]

Good point! I know it will kill roundworms and I think it kills hookworms as well, I'll have to double check.

pugasaurus wrote:I think that heartworms are a relatively recent problem and I know they started in the south and are slowly moving northward, there's even been a dog that tested positive in Alaska (thought he may have been bitten in the Lower 48) so I think that's why people didn't worry about heartworms years ago.

Heartworms were a nightmare when I worked for a vet in 1980 back in Kansas City, Missouri- so they are not too recent a problem, they've been around at least 30 years. Back them, you had to give a pill daily. I was once present at a necropsy of a dog who died of them and when the vet opened the dog's over-sized heart, heartworms poured out like spaghetti. It was awful.

For now, mosquitoes up here don't carry heartworms. That dog you talk of could be (like you say) from the lower 48.

Alaska doesn't have fleas, ticks that bother dogs, heartworms, snakes or poison ivy.

Why don't all my pug friends move up here?

Oregon (where I was born) won't have the same problems that we have here in the south. Not something I worried a lot about even when I lived in So Cal. Not real prevalent, especially if you did not keep your dog outside at all times. Even my HUGE breeds weren't outside dogs. The scare is good, but the geographic area is a huge contributing factor too. Do not feel bad. When we know better, we do better....

This is an interesting discussion, about the geographic spread.

In Australia, 30 years ago heartworm was pretty much unknown outside the tropical areas in the north. We southerners (I was in Adelaide at the time) only gave heartworm meds if we were taking our dogs north for a show or whatever. I remember you had to start them on the meds (daily back then) at least a month before you left and continue for a month after you got home.
Gradually, over the decades, mosquito populations further south became infected - usually in the largest cities first, which would indicate that dogs which had travelled north had become infected up there and brought it home to be spread to the local mosquito population. In many less populated areas in the south, it is considered safe to only use heartworm prevention in the spring and summer months.
Furtherest south (excluding Antartica which has no mosquitoes) is the state Tasmania and heartworm is pretty much unknown there so far. As long as everyone there who is taking their dogs north or (bringing them south) medicates effectively, it should stay that way.

Preventative is a MUST here in mosquito infested FL.

I think CFPR has taken in 6 HW + in the last 6 months. Most do very well through the treatment. Some may develop inlarged hearts.... which can be treated with meds.Depending on how long they have been positive and how old they are the determinning factors.We had one almost fail last week but we pulled him through... He spent another 3-4 days at the clinic on IV'S.

I have always given year round even when I lived in Illinois because the heartworm meds that I use also protect against other parasites.

Good point! I know it will kill roundworms and I think it kills hookworms as well, I'll have to double check.

It depends on the brand of "preventative" you give. For instance:

Heartgard (ivermectin) is for heartworm only

Heartgard Plus (ivermectin plus pyrantel) is for heartworm, hookworms (3 types) and roundworms.

Sentinel ((lufenuron plus milbemycin oxime) is for heartworm, hookworms (one type), roundworms, whipworms and fleas.

Interceptor (milbemycin oxime) is for heartworms, hookworms (one type), roundworms and whipworms.

Revolution (selamectin) is for heartworms, fleas, ear mites and dog ticks. As opposed to the previous 4 products, it works to kill adult heartworms rather than those in the larval stages. It does not work against hookworm or roundworm but it can be used for sarcoptic mange.

Advantage Multi ((imidacloprid plus moxidectin) is for heartworms, hookworms (2 types), roundworms, whipworms and fleas. I could not find whether it deals with baby or adult heartworms.

(Frontline and Frontline Plus are for fleas and ticks and do not deal with heartworms.)


As with any medication, it is important to do the risk/benefit analysis. These products are each toxic and can have a seriously adverse effect on the thyroid, liver, nervous system etc. I'm not advocating not using heartworm preventatives; I'm just saying we need to know what we're putting into our dogs' bodies and the possible side effects/ramifications. I have added the clinical names of these products so anyone interested can check them out on the internet (e.g. on Wikipedia) as well as checking the monographs of the products. Personally I don't medicate for heartworm "prevention" after weighing up a number of factors (based on extensive research about the prevalence/characteristics/migratory patterns etc. about mosquitoes in my area) but it's a decision I challenge myself on repeatedly.

It is also interesting to note that these are not heartworm "preventatives' in the true sense of the word. They are pesticides - that is, they kill existing heartworms or heartworm microfiliae (babies, larval form). And it is also VERY important to get your dog tested before starting to give heartworm "preventatives" because if the dog already has heartworms, treatment has to be done slowly and cautiously; it is possible that a normal monthly dose will kill a dog with pre-existing heartworms too quickly and the corpses will clog the lungs and can kill the dog.

And just as a little bit of trivia, did you know that:
- it is estimated that there are between 2500 and 3500 species of mosquitoes world-wide
- there are about 200 species in North America, of which about 75 are found in Canada
- only about 16 species of mosquitoes east of the Mississippi River can carry heartworm
- only the female mosquito bites (and therefore transmits heartworm), and she does this to acquire a blood meal necessary to lay eggs; not all species will bite humans and/or dogs (I forget how many offhand)
- most mosquitoes are territorial, staying within a mile or two of their original habitat. A few can range up to about 20 miles
- to infect a dog with heartworm, a female mosquito of the appropriate species must have bitten an animal (e.g. a coyote or another dog) which is already infected by heartworm microfiliae. The microfiliae then mature within the mosquito's body and if the mosquito bites a second animal (e.g. your dog) when the microfiliae have developed to Stage 3, that animal will probably become infected. See the graphic on the middle of this page: http://www.heartwormsociety.org/pet-owner-resources/heartworm.html#lifecycle.
- the timing of the development of the microfiliae, however, is dependent on temperature. So if a mosquito bites an infected coyote in, say, September and the region then experiences a cold snap (under 55 degrees F), the microfiliae will either die off with the mosquito (in extreme cold) or lie dormant until the temperature rises again. Over 80 degrees F (27 C) is ideal development weather.
- mosquitoes die in very cold winters but eggs will survive which is why there are still mosquitoes in places like Alaska in the spring. (Exceptions being "diapause" where some species' females mate in the fall but don't have a blood meal (aka bite), then go into a dormant state through winter; when spring comes and they wake up, they bite to get the blood meal and can then lay their eggs
- heartworm microfiliae don't show up on testing; only the mature adults do, so a dog can test negative for heartworm and be heartworm positive a few months later. That's why many people do twice a year testing.

heartworm microfiliae don't show up on testing; only the mature adults do, so a dog can test negative for heartworm and be heartworm positive a few months later. That's why many people do twice a year testing.

Really? What was I seeing under the microscope when we'd test dogs for heartworms back in the 80's. I thought it was the microfilia? Of course, that was almost 30 years ago, so I could be wrong. The adults lodged in the heart, so we couldn't see those.

<<< off to research. LOL

Maryjo wrote:

heartworm microfiliae don't show up on testing; only the mature adults do, so a dog can test negative for heartworm and be heartworm positive a few months later. That's why many people do twice a year testing.

Really? What was I seeing under the microscope when we'd test dogs for heartworms back in the 80's. I thought it was the microfilia? Of course, that was almost 30 years ago, so I could be wrong. The adults lodged in the heart, so we couldn't see those.

<<< off to research. LOL

I'm glad you brought this up, MJ. There are different types of heartworm tests - Knotts, antigen, SNAP, etc. which show up different things. I'm also off to do more research.

So I did a little more research and found out that in "the old days" (sorry, MJ), the tests detected only microfilariae but now most clinics use antigen testing which detects adult females.

http://www.peteducation.com/article.cfm?c=2+2096&aid=743:
"In the 1960's, before more sophisticated tests were available, heartworm testing involved looking for the microfilariae in a drop of blood on a microscope slide. A better test, the Knott's test, was developed to concentrate the microfilariae from a larger portion of blood through centrifuging it. This gave veterinarians a better chance of finding the microfilariae.
Later, filter tests became available. In these tests, the blood cells in the blood were lysed (broken) by a special agent that did not affect the microfilariae. The resulting liquid was then put through a very fine filter. The microfilariae were concentrated on the filter. The filter was stained and examined under the microscope for microfilariae."

But then,
"Veterinarians soon recognized that some animals could have heartworm infections without having microfilariae in the blood. This occurs if only male worms are present or if the females are not laying microfilariae at the time of the test. It was obvious that better tests were needed."

So they developed antigen testing which detects the presence of adult female heartworms:
"Serologic tests were developed to identify antigens (small protein and carbohydrate components) of heartworms in the bloodstream. There are different varieties of this test. One of the most common types is called an ELISA test. Some test kits run one sample at a time and can be done right in your veterinarian's office. Others are designed to test multiple samples in large batches. This batch-type of test is generally performed by outside laboratories to which your veterinarian sends your dog's blood.
Although the antigen tests were much better than the filter test, we still could not identify all cases of heartworm infection because antigen tests will only be positive if adult female worms are present, since the antigen detected is from the worm's uterus. If the heartworms were not fully mature, or there were only male worms present, the antigen test result in infected animals would be falsely negative. This means the test result is negative when the animal is really infected." This antigen testing is the one used by most vet clinics (http://www.pets.ca/dogs/tips/heartworm-testing-in-dogs-pet-tip-121/). "The antigen test is most commonly performed, and is very accurate in dogs." (http://www.avma.org/animal_health/brochures/heartworm/heartworm_brochure.asp)
" In most practices, microfilarial detection has been supplanted by or supplemented with antigen testing," (http://en.wikipedia.org/wiki/Dirofilaria_immitis)

Now they have developed antibody testing. "This is the test most commonly used in cats. This test will be positive even if only one male worm is present. But this test has a downfall, too. Although it is very good at giving positive results when an infection is present, false positive tests are more common with this test than the antigen test. A false positive result means the test result is positive when no infection is present."

note: all quotes come from http://www.peteducation.com/article.cfm?c=2+2096&aid=743 unless stated otherwise

Well, I have lost a dog to heart worm--or rather my father did. Ages ago, in the late 60s, one of his dalmatians suddenly screamed, jumped up and keeled over dead. He did an autopsy and it was heart worm.

I do use meds--usually Revolution. Yes, I worry about it a lot--especially with Tank, but so far, no reactions and I've avoided a couple of cases of sarcoptic mange with foster dogs who had it.

It's a personal choice. A woman up here who has treated her boxer for heart worm, but wasn't always "on time" with the meds had her boxer test positive. they re-tested several times to make sure it wasn't a false positive and it wasn't--and this was in downtown Toronto. We never will know how Tallie got heart worm, but her vet said that being off by a couple of weeks can be enough for a dog to be infected. Fortunately, her pug didn't test positive.

I have to say that that incident scared me a fair bit--she lives about 20 blocks from my house.

Yep, it scared me too. It's pretty close to top of mind with me - last Friday I had Denver tested for HW when he had his other tests done. And I agree it's an individual choice based on a risk assessment.

Canada is luckier than the US as far as prevalence. In 1996 and 1997 there were 697 and 812, respectively, reported cases of HW in dogs in the whole country. Ontario has the highest prevalence of HW in Canada - commensurate numbers for the province in 1996 and 1997 were 586 and 676. Even still, the current estimate is that Ontario heartworm positives account for less than 2/10 of 1% of dogs in the province, although the percentage rises to about .65% for dogs not getting the "preventatives". In 2002, there were 268 reported canine HW cases in Ontario, mostly in the Golden Horseshoe. In 2005 there were 242 cases in the Ontario and this rose to 676 cases in 2008; some people attribute the increase to bringing in abandoned pets from Hurricane Katrina (e.g. 46 of 63 cases reported in the Hamilton area). These numbers are probably all understated because of under-reporting.

Sources:
http://www2.ovc.uoguelph.ca/PathoBio/Heartworm/can_gen97.html
http://www2.ovc.uoguelph.ca/PathoBio/Heartworm/Ontario02.pdf
http://www.ashbridgesbayanimalhospital.ca/Heartworm-Season.page
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1476355/
http://baycitiesanimalhospital.ca/custom_content/c_47700_heartworm_blood_test.html
http://www.vita-tech.com/downloads/maps/Heartworm_Data_2007_EN.pdf
http://www.torontosun.com/news/columnists/peter_worthington/2009/10/10/11363691-sun.html