I don't know where you live, besides along a deer path, lol, but here's a map-

We give HWPs all year around. We live in a dark red state and I've killed mosquitos in Jan, Feb and March, too.

Here is a link that might be useful: Here's a map- click on heartworm...

Per the link below:
Canine heartworm infection is widely distributed in the United States. Heartworm infection has been found in dogs native to all 50 states, and is considered at least regionally endemic in each of the contiguous states and Hawaii.

I have had a dog that had heartworms, and the treatment was expensive, as well as risky imho, required an overnight stay at the vet, and had to be crated (or kept very still) for 30 days.

Here is a link that might be useful: CANINE HEARTWORM DISEASE

Flamingo answered your question, but I can share this story:

Several years ago my Wolfy, 12 years old at the time, got heartworm. I had not been giving Heartgard. My vet wanted to start him immediately on a very expensive treatment program that would put his life at risk. I did some research on the Internet, and found the "slow kill" method of treating heartworm with Heartgard was recommended in Wolfy's case. The vet disagreed, so I sought another opinion. The second vet agreed completely with the slow kill method, and furthermore said at Wolfy's age he was not likely to die of heartworms.

So Wolfy received Heartgard every month, and did well for that year and beyond. I just thought I'd share this in case the information might prove to be useful for someone.

Oh, one other thing about the map I linked to- I don't know what the real numbers are, since they only go by "reported" cases. I can imagine that for every dog on HW prevention, there are several that are not treated or diagnosed.

You can click on your state and get a county-by-country report, but I would keep the above in mind. One of our dogs got a false positive on her HW test, one year. That scared me to death, because she's a collie and the treatment would have been even scarier for her, collies are more sensitive to things like insecticides.

Susan, I don't think putting a 12 year old dog thru the dangerous treatment would have been wise at all! I have never heard of the slow-method, though.

One vet told me no because my dog wasn't around other dogs. My current vet says yes because it's transmitted by mosquitos. I don't do it because in all these years there's only been one case in my area. But that's just my choice.

Zeetera, I'm glad you got rid of your first vet because heartworm is transmitted by mosquitos, as your second vet said.

I would consult my vet if I had an question as to whether heartgard is really needed, and I am 100% positive of the answer you will receive. Just because someone says it on a forum doesn't mean it's true.

I volunteer at my local animal shelter and not all cases of heartworm are reported by vets, so the maps may not be accurate. I've seen dogs with late stage heartworm and its awful. I don't live in a high incidence area, but I have always given my dogs heartworm meds. An ounce of prevention...

I can only speak for my area. My vet tells me that with all the testing they have done here not one case has come up in their practice for dogs that live in my area. My dogs are indoor dogs who only associate with dogs I know. The only fleas I have ever dealt with are the ones they had as puppies. Once those were eradicated neither has ever had any.

Now that doesn't mean all dogs who live here don't need the meds. If you travel with your dog, hunt with your dog and take it to nearby water areas it would be wise to have it on heart worm meds. If I lived just 30 miles away in one direction my dogs would be on heart worm meds at least during mosquito season. Were I to take a trip with my dogs they would be tested and put on meds for the trip.

Also I get honest answers from my vet because he knows I take care of my animals.I bring them in for regular check-ups and don't don't the wait and see thing when they are ill.

I am also very very hands on in my animals' treatment plans. I don't bring "Muffy" to the vet in a bag, hand it over to staff and turn away so I don't have to see poor Muffy get her shot. LOL

Often vets will not share information with clients because they fear that the client will not bring the animal in to be seen. For example it's fine to do vaccines at home but ONLY if you are also taking your pet in for annual exams. Some vets only see the animals when the vaccines are due. So they encourage things that at the very least will allow them to see the animal now and then.

It really comes down to how reponsible the owner is, where the dog lives and what it's exposure risk is to whatever the issue.

Unlike so many would believe most vets have the dogs best interest at heart.

I wanted to be a vet when I was younger. Today it would not be something I would not want. I would either go insane or be in jail. I wouldn't be able to have the patience needed to deal with stupid pet owners.

I wouldn't consider NOT giving a heartworm preventative.

I have seen what a dog (and owner) have to go thru for a case of heartworm, and I wouldn't want to risk it at all. An ounce of prevention is worth a pound of cure.

I grew up in the area where Wildchild lives and moved to Southern CA when I was 20. I have always had a dog until just a few years ago, and all lived to old age.

Never heard of heartworm when I lived in northern or southern CA. It wasn't until I started surfing the internet that I became aware. I still don't know anyone giving heartworm meds to their pet.

I was shocked to see that CA is a dark colored state for all the maladies listed.

Jodi-

I agree with Suzique. Year round.

Sue

I can understand the first vet's thinking, somewhat- the mosquito has to bite an infected dog to "grow" the microfilaria larvae which they then give to a different dog when it bites him. So if you live in a place where the dogs are few and far between, chances are a little better that your dog won't be bitten by an infected mosquito.

I still wouldn't take the chance, though. I worked for a vet and I've seen firsthand what HW's can do to a dog, in all stages. We did a necropsy once on a dog and its heart was completely choked with long white stringy heartworms, no blood was moving around thru all that. Mild cases- the dogs cough a lot. The treatment is very hard and dangerous and if the medication got out of the vein, it killed the surrounding tissue. Yep, giving a dog a chewable pill once a month is SO easy and worth it.

with out fail all of my dogs stay on heart worm preventative. I have had 2 dogs that had to be given the treatment for heart worm infection and it was very expensive and very difficult on the dog. My current little one had contracted it prior to coming to us, I got her tested immediately and she was found to have early stage so we put her through the treatment which was so hard on her but she was successful.

I also had a dog that got heartworms while on the pill filarbits which years ago was what we gave them it was a one a day chewable pill, but it was not 100% and in actuality it only takes one bite from one mosquito to infect a dog, he apparently got bit by that mosquito and got infected even though he was taking those pills, his treatment back then was so much worse than it is today even though it is still very bad today. He nearly died, the injection site got very infected and we thought he would lose his leg.
I would never fail to give my dogs heartworm prevention after going through that, they are my children so I would do for them just as I would for my child.

Here in Houston mosquitoes are everywhere, it is actually very very common to find animals with heartworm here. In the odds game leaving one with out treatment here is pretty much like using a fully loaded gun to play Russian Roulette, you are doomed.
But knowing what I know I would give them the preventative no matter where I lived, the risk is simply not worth it.

We are in a hign incidence area. Year-round prevention is the way to go.

I notice the map is courtesy of a drug company.

I notice that when I check Illinois and Wisconsin, the counties with large numbers of heartworm cases reported are also the most populous (and perhaps most wealthy). Who knew mosquitos were so picky? Guess they don't like Southern Illinois -- makes no sense.

How long does it take for a new case of heartworm to affect a dog who has just tested negative for it?

If Heartguard prevents heartworm, why does a dog have to be tested for heartworm after having been on it 12 mos. a year for all its' life?

From another discussion. An excerpt on one doctor's r take on the issue. Mind that this is only one opinion but the science behind it is factual. So it really matters where you live, the climate and the season.

How Heartworms Infect Dogs: It's Not Easy!

"Let's take a look at how the heartworms themselves (called Dirofilaria immitis) do business. Seven steps must be completed to give your dog a dangerous heartworm infestation:

1. To infect your dog, you need mosquitoes (so you need warm temperatures and standing water). More specifically, you need a hungry female mosquito of an appropriate species. Female mosquitoes act as airborne incubators for premature baby heartworms (called microfilariae). Without the proper mosquito, dogs can't get heartworms. Period.

That means dogs can't "catch" heartworms from other dogs or mammals or from dog park lawns. Puppies can't "catch" heartworms from their mothers and moms can't pass heartworm immunity to pups.

2. Our hungry mosquito needs access to a dog already infected with sexually mature male and female heartworms that have produced babies.

3. The heartworm babies must be at the L1 stage of development when the mosquito bites the dog and withdraws blood.

4. Ten to fourteen days later, if the temperature is right the microfilariae mature inside the mosquito to the infective L3 stage then migrate to the mosquito's mouth. (Yum!)

5. Madame mosquito transmits the L3′s to your dog's skin with a bite. Then, if all conditions are right, the L3′s develop in the skin for three to four months (to the L5 stage) before making their way into your dog's blood. But your dog still isn't doomed.

6. Only if the dog's immune system doesn't rid the dog of these worms do the heartworms develop to adulthood.

7. It takes approximately six months for the surviving larvae to achieve maturity. At this point, the adult heartworms may produce babies if there are both males and females, but the kiddies will die unless a mosquito carrying L3′s intervenes. Otherwise, the adults will live several years then die.

In summation, a particular species of mosquito must bite a dog infected with circulating L1 heartworm babies, must carry the babies to stage L3 and then must bite your dog . The adult worms and babies will eventually die off in the dog unless your dog is bitten again! Oh, and one more thing.

Heartworms Development Requires Sustained Day & Night Weather Above 57˚F

In Step 4 above I wrote that heartworm larvae develop "if the temperature is right."

The University of Pennsylvania vet school (in a study funded by Merial) found: "Development in the mosquito is temperature dependent, requiring approximately two weeks of temperature at or above 27C (80F). Below a threshold temperature of 14C (57F), 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."

Knight and Lok agree: "In regions where average daily temperatures remain at or below about 62˚F (17˚ C) from late fall to early spring, insufficient heat accumulates to allow maturation of infective larvae in the intermediate host [the mosquito], precluding transmission of the parasite."

The Washington State University vet school reports that laboratory studies show that maturation of the worms requires "the equivalent of a steady 24-hour daily temperature in excess of 64 degrees F (18 degrees C) for approximately one month." In other words, it has to be warm day AND night or development is retarded even if the average temperature is sufficiently warm. They add, that at 80 degrees F, "10 to 14 days are required for development of microfilariae to the infective stage."

Jerold Theis, DVM, PhD, says, "If the mean monthly temperature is only a few degrees above 14 degrees centigrade [57 degrees F] it can take so many days for infective larvae to develop that the likelihood of the female mosquito living that long is remote."

I have never found this temperature-dependent information on a website promoting "preventatives," but only in more scholarly works not easily accessed by the public. There is, as far as I can find, only one mention of temperature on the Heartworm Society (on the canine heartworm page) and none in the Merck/Merial Veterinary Manual site or Merial's heartworm video even though Merial funded the UPenn study.

The Society also reports, "Factors affecting the level of risk of heartworm infection include the climate (temperature, humidity), the species of mosquitoes in the area, presence of mosquito breeding areas and presence of animal reservoirs (such as infected dogs or coyotes)."

Basically people have to have a good honest discussion about this with their vet and decide what is the best course of action for their individual pet. Some dogs may need heartworm prevention all year long (the minority) for a few months out of the year, and some never.

If you could take a chewable med every month to prevent cancer or heart disease would you? Why wouldn't you give your pet the same opportunity?

If you could take a chewable med every month to prevent cancer or heart disease would you? Why wouldn't you give your pet the same opportunity?

I would have to weigh the potential side effects of the drug and what else it might be doing to me while preventing the illness I was taking it to avoid first. Then I would have to weigh the odds of taking ill from the medication or getting the disease. You don't throw the baby out with the bath water.

When you give heart worm meds you are basically giving your dog pesticides every month. Those who don't know what kind of heart worm meds they are using may also be doing flea treatments. (some heart worm meds take care of fleas also) so now the animal is getting a double whammy of pesticides.

I typically stay on the holiday side but do occasionally come here to lurk. this subject has become very close to my heart as of late. I will share our story, (sorry if it's a bit long)
Everyone has their own choice and I respect that. That being said, I too , can firsthand tell of the horrible throws HW treatment can bring.
I had 3 pugs in June , a friend of mine was director of fundraising for our local HS. She called me saying they had an older pug boy there who was very ill/had been there 2.5 months and would I agree to foster him. Off I went to collect my little charge. In the corner of the quarentine room in a crate was a pitiful looking older gentleman.It was obvious he didn't feel well so I left him a blanket with toy that smelled like my own boys.We now have (J.R.),now named Mickey coming to visit.
Off I went to acquire a new crate, leash-harness, vitamins, eye drops and all the other things he would need.Got home and set all this up [oh and tell my husband what I've done...lol]and waited. The next morning DH and I went to collect him. DH hugged him all the way home as I was saying "he's not staying".
The next morning brings a vet appt where we learn he is approx 7 yrs old, HW positive for how long we do not know (on top of the end of a horrible demodex episode,dry eyes, terribly long toenails, dry/cracked nose, awful brittle hair) so treatment begins. I've always treated my 3 religiously with preventative so this is not something I ever expected to have to endure.
That being said , 30 days of doxycycline antibiotics to kill the Wolbachia is the order, listen & watch with sadness as the poor little fellow coughs/hacks/gags and can't catch his breath until he's to tired to move,keep waiting , then start the shots.
Fast forward to Oct 14th I dropped him off at the vet at 8 am. When called to collect him at 5 that evening, I found a very drugged and obviously much in pain little boy but I have an extensive relationship and 20 years with my vet allowing conveyance to go ahead and bring him home.
Take him home, put him on full time lockdown crate rest is the order (for the next 30 days). This is awful in itself for a little fellow that WANTS to be outgoing.
That was Wed, by Sun evening he was coughing in such a horrid way you can't imagine. Back to the vet, an infectious case of fighting fluid in the lungs , add 5 more medicines and keep on plugging away. He's mad , still in lockup , I'm stressed to the max with worry... still plugging away.
We're now 2 weeks 2 days into this and in his opinion , he's FINE and wants OUT.. Not a chance says the warden!!
2 more weeks, we go back and do this again then 4 more weeks of doggiejail. He will get out of "jail" on November 9th if all goes well.
Some of this may mean nothing to you, but ,it's a personal mission of mine for people to truly understand HOW this horrid disease drags out when it's so much easier to prevent.
The financial cost of all this ... OVER $600.00 in $$ , hours of worry/tears on my part and pain on his, that could probably been prevented for so much less.
Thank you for letting me share.
P.S. ~Mickey is being adopted by his adoring Failure Foster Parents!~ :)

So : in saying all of that , do I think prevention is neccessary? Absolutly.
Have I weighed the pros cons of inhibiting excessive drugs into their systems monthly? Absolutly.
The end determination is , yes (for me), it's definatly worth it. The very small amount induced monthly is in my opinion far better than the awful distress , failure of health , and the shots (which are a form of arsenic compound), the emotional stress brought by day long crating used to treat this dreaded issue.

That should have been Sept 14th , not Oct.
and just to put a face to his story..
Here is J.R. (Now Mickey) when I first met him....

and here he is a few days before his treatment began (11 weeks in my care)..

We are also in Arkansas. Many years ago we also had one of our dogs contract heartworms while on one of the earlier, less effective, preventatives. Our dogs have always been primarily house dogs with a fenced yard and don't mingle with unknown dogs. Fortunately, our boy was young, survived the treatment, and lived to a ripe old age, but we wouldn't even consider not using a preventative around after that experience. We have a 14 yr old and a 10 month old on interceptor now. On the other hand, when DD and her pup moved to the Colorado mountains, the vet there told her meds were not necessary in that region. However, the vet also told her that he should go back on meds before visiting heartworm prone areas and he does go back on meds each time he visits here. I'd do what my vet says is best for your area.

Milosmom--what a difference. After all that, how could you give him up? Very cute dog.

Milosmom, you are an angel with a huge heart. MIckey is adorable and very, very lucky. Your story is compelling to anyone who loves their pets. I had a friend who would not use frontline on her dogs because of the pesticide factor and I could never understand it. I have religiously used frontline and heartgard on my pups, and I don't see any lesser quality of life or longevity due to preventative treatments. You can rationalize all you want, but prevention saves lives and nothing anyone says can convince me otherwise.

I dunno 'nuthin bout heartworm, but this whole thread reminds me of parents who refuse to vaccinate their kids because they never saw a case of polio or smallpox. They think the vaccines are dangerous.

Just sayin'...

Just because they are on prevention don't be fooled by thinking they are safe...My last St..tested positive for heartworms, while at the same time Winnie didnt..We went the slow method and six months later Bear was HW free..but at that checkup we found his cancer..
Fast Forward 9 months later..we got Tank...both dogs were on prevention..NEVER missed a dose..we always watched them and made sure they took them...A year later Tank was tested and was found to be positive..Winnie was also tested and found positive..We have changed preventions..Tank now gets the Pro Heart shot and Winnie will start it next month if it is safe for her to do so.
Our next door neighbor has a dog and he has never been to the vet and he is eat up with HW..The sounds coming out of that dog is enough to make you cry if you hear him..Pitiful and all they say is he wont live much longer..They also have a half collapsed swimming pool full of water..can you say Mosquito heaven??

Any disease that is airborne scares me. Sure, there may be local "pockets" of the disease, but anything that is airborne travels.

I don't know that anyone can say with any certainty that a map will remain constant. That's like saying clouds stay in one place. But risk is different for each person, so do what you thing is best for your pet. You are the only one that will have to live with the decision.

No preventative is 100% reliable, that's why they want you to test for HW every year. And like I said, a false-positive is not unheard of, Shanzie tested positive twice in the office and then we sent blood to a lab where it came back negative.

And just because you give the pill, doesn't mean it stays down long enough to work- one time our dog Mariah threw up about 15 minutes after she got her monthly pill and I just happened to see it happen, she was out in the yard. So I was able to give her another pill and everything was fine, but if I hadn't noticed, she could have gotten infected that month.

Yes, the map is sponsored by a drug company, but if you'll notice, it's not all dire news, click on the state, hover over the county- if they were cheating on the stats, I'd expect to see higher numbers of cases in more counties. Most of the pockets of really bad areas are very localized, but it bumps up the numbers for the whole state.

I think the chart is misleading because it probably relies on reports of positive heartworm tests from vets. The chart shows low incidences in all of Illinois except around Chicago and suburbs. It has to be skewed, for that reason alone.

Nobody's reporting on animals in rural areas, centainly not from any puppy mills, whereas almost every dog in my town is vaccinated and licensed -- and most homes seem to have at least one dog.

Wildchild -- Very interesting stats about the (un)lkelyhood of a mosquito surviving to pass on infection, at least in my home climate. Thanks for posting that.

When I think of an "airborne" disease, I think of something transmitted by a cough or a sneeze. I would call heartworm a "bloodborne" disease. Airborne would imply that dogs could infect each other with heartworm.

Who do you think should be keeping track of heartworms in dogs, if not the vets, chisue? Where better to compile the information from?

And there are several western IL counties with fairly high number. Usually if you get near water, the numbers go up.

The good news for you is, no one is going to force you to buy heartworm medications for your dogs.

"Mosquito-borne" would be a more accurate description, as opposed to airborne or blood-borne, IMO, since a dog has to be bitten by the infected mosquito. Sort of like West Nile virus...

I think of mosquitoes as airborne vectors. They are carried in the air, like saliva from a sneeze. Whatever - argue with Webster.

I think the point was made.

Yes - as far as I am concerned. Expensive, yes. As expensive and as heartbreaking as your pup contracting Heartworm - NO!

flamingo -- That's my point. All we know about the incidents of hearworm comes from vets. They can only report on animals they treat who test positive for it.

Nobody knows how many animals (or people) are infected with *anything* if a vet (or MD) isn't testing them for it.

That's at least one way the chart is skewed -- not saying it doesn't tell us there are animals testing positive!

One would think that where dogs are routinely prescribed Heartguard there shoud be FEWER incidences of heartworm, not more. I wonder if shelters and pounds figure into this -- there are more animals being tested there, and there are more concentrated in some areas.

PS -- I'm just 'contrary'. I like to look at more than one side of things. Did y'all miss that our Westie, almost 12, has been on Heartguard all his life? (Along with the three that came before him.)

I brought this up with my friend last night. She worked for the county animal shelter (in the hospital area where you see everything) for over 13 years. I asked her how much heartworm they saw since it would make sense that many dogs the shelter gets are often not well cared for during their earlier lives either.

Her response after thinking about it a bit was "not that many" and those that were were from out of the area.

Our area vets and shelters were on the alert after Katrina and even that didn't turn out to be as epeidemic as first believed.

So when a the county animal shelter ha which has hundreds of animals pass through each month doesn't see but a few isolated cases of heartworm that tells me it is simply NOT a big problem where I live.

Chisue, You are so right that statistics can be skewed to show what the folks behind them want them to show.
It's junk science to rely on only reports that do and not how many don't.

Those maps put out by the manufacturers of the pesticides are I am quite sure printed at the peak of the problem. They should have to date them and show the different seasons.

Vets prescribe year round because they know the human half of their clients are forgetful and often do not keep track of their pet's well being. Easier to tell them once a month than to tell them to bring in their animal for testing at the beginning of mosquito season.

Now I don't know if my county is relatively heartworm free because of routine meds or not. But I do know that we do not have a huge mosquito population, I don't live near standing water and although our days are moderate and would fit the climate needed during the warmest months our fog bank and cooler nights would pretty much eliminate the life cycle during most of the year.

In the past I put my pets on meds during the warm season. After discussing the issue with my vet (actually I had this discussion with several) we decided it was not necessary.