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Heartworm positive rescue dog

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Heartworm positive rescue dog
  •  Last weekend, my husband and I adopted a dog (who we've named Henry) from a local animal rescue group. Henry is a Feist, a little over a year old, and had been at the rescue since last May. According to the paperwork we were given, Henry was heartworm negative (hw test was in May) and had been on monthly preventative (Ivermectin liquid) at the shelter. Well, we brought him to the vet a couple of days after bringing him home and just got a call last night from our vet telling us he's heartworm positive. We had purchased Interceptor to give him for prevention, but the vet had us return it after the diagnosis because she was worried he might have a reaction to it.

     He doesn't have any outward symptoms (he's healthy looking and super energetic), but I'm very, very worried. We lost our beloved 7-year-old beagle last year after a very sudden and unexpected illness (he was diagnosed with aggressive liver cancer after about 3 weeks of showing symptoms, and died the day after diagnosis), and I'm incredibly upset at the thought that something might happen with Henry now. The vet has put him on Doxycycline and we've got another appt on Monday for x-rays and more blood work, but I'd just kind of like to go in having an idea of what to expect and what kind of treatments there are for heartworm.

    Does anyone here have any experience with HW positive dogs? Is treatment a lengthy and/or painful process for the dog? How serious might the heartworms be after a negative test (followed by monthly Ivermectin) 8-9 months ago?

  • It depends on whether the test was accurate and whether or not it was done after someone gave him heartworm preventive.

    I actually have a lot of experience both with heartworm positive dogs *and* liquid ivermectin.  The Interceptor is a safe drug -- VERY safe (and always my choice).

    Honestly I'm at work and I can't take long to post now -- but I'd be happy to help you on this.  It's not a simple yes or no, good or bad things -- and it's likely not a hugely serious case of heartworm.  But knowledge is power in this regard and I can give you a lot of information.

  • The vet said the lab they double -test the blood when it tests positive, so she's pretty sure it's accurate, and the rescue said his last heartworm preventive was a little over two weeks before we had him tested at the vet.

    I would very much appreciate any information you have when you get chance; I have absolutely no experience with heartworm (we lived in North Central FL for most of my beagle's life so we were VERY vigilant with the hw preventive because of the mosquito issues down there) and I'm very worried about Henry. I do know we're supposed to get another kind of preventive on Monday to give with the Doxycycline (there were 2 kinds she recommended for hw+ dogs: Heartguard, and something else that I can't for the life of me remember the name of), but from now until then I'll probably worry myself sick over his prognosis.

  • Someone on another board had a dog who was HW positive.  As I recall it was about 6 weeks of treatment, and she had to keep him inactive - sort of like "bed rest."  That was the hardest part for her -- and the dog was age 8, not a young one!  Dasher was very sick at the time he was diagnosed; that was 4 years ago, he is a happy lab now, lol!  So a positive outcome IS possible.

    I don't know how it works when the dog changes owners.  With the same owner, if you can establish that the meds were properly given, the meds manufacturer will pay for the HW treatments; I think that is pricey, about $600?  Something to discuss, look into.  I think your vet helps with this but I'm not sure.

  • A little information on heartworms -

    (1)  It takes 6-7 months from the infecting mosquito bite before a female heartworm is mature and can be detected [either by the presence of babies (microfilaria) or by the antigens (a chemical) she produces].
    (2)  Male heartworms are not detectable by any current test.
    (3)  Heartworm "preventatives" don't prevent anything but adult heartworms.  The "preventatives" kill young heartworms, but not after about 45-days from the infecting mosquito bite.  After that time the young heartworm is too old for a "preventative" to kill it.
    (4)  Microfilaria are killed by "preventatives", but unless they are sucked up into a mosquito (for their next growth phase) they will die of old age anyway.
    (5)  A dog on "preventatives" will rarely test positive for microfilaria, so only the antigen test should be used.

    A dog from a rescue or shelter who tests negative for heartworms and was put on "preventatives" should always be retested 6-7 months later to see if (at the time of the previous test) it was harboring any young heartworms who were (a) alive over 45-days after the infecting mosquito bite and (b) too young for the microfilaria or antigen tests. 

    It is statistically improbable, but a dog with only male heartworms will test negative for heartworms on any current test.

  • My current foster dog is HW positive. He came from a hording situation where he was living in filth in Mississippi. He's at my home now under strict confinement.  He will be getting his third spinal injection to treat the HW in a few days then go to his new home.  It is a very painful and long process, difficult on both the caregiver and the dog. The HSUS is paying for all of his medical bills, thankfully.

    Did the vet do a microfilariae test, looking at his blood under the microscope for the parasites that live in the blood?  It is usually recommended to follow up a positive test with a blood smear. It takes 6 months from the time the dog is infected to show up positive on a test.  That means he would have had to had HW for at least 6 months prior to his positive test.

    The most difficult part of the treatment is that the treatment can be as deadly as the parasite. Usually the treatment is done over a long period of time so that the heart doesn't stop. There are many options, some more expensive then others and can run in the $2,000 range for the safest treatments.  Most dog's don't have outward symptoms and will live a very normal life.  Very strict confinement is a must during the treatment, with the worms dying in the body it is important not to overstimulate the heart so that the dead worms do not cause blockage in the arteries. It takes a while for the body to absorb the dead worms as they are being killed off so the treatment must be done very slowly.  Hopefully your vet can discuss what your best option is for your dog.

  • Bay
    He doesn't have any outward symptoms (he's healthy looking and super energetic), but I'm very, very worried.

    Please don't worry!!  Henry has an excellent chance of recovering with no after effects.  The worst problem you will probably have is keeping a 1-year-old Feist inactive.  He is not going to like that especially if he does not feel sick.    <big grin>

    A young dog with no symptoms who has been on a regular preventative after a negative test
    (1)  will not have a lot of microfilaria in his system and
    (2)  is unlikely to have a large number of heartworms.

    The less dead mass of heartworms that a dog has to deal with during treatment to get rid of adult heartworms the less risk to the dog.  Your vet is current enough to know to use doxycycline, so it sounds like you are in good hands.  However, I don't understand his/her having a problem with Interceptor since that will not kill adult heartworms and (if the rescue was truthful) Henry shouldn't have much in the way of microfilaria.

    Here is a site that you really want to bookmark:  www.dogaware.com

    http://www.dogaware.com/health/heartworm.html  (Here is a quote, but read the whole page.)
    "Recent research has shown that treatment of heartworm-infected dogs with doxycycline weakens and sterilizes adult heartworms, kills all migrating larvae and half of the juvenile worms, and reduces the adverse effects caused by heartworms, and by their death. Doxycycline should be given prior to treatment with Immiticide, to reduce the risk of treatment. It should also be used as part of a "slow kill" treatment protocol when Immiticide is not used.

    If you plan to treat with Immiticide, give doxycycline at the rate of 10 mg per kilogram of body weight (about 5 mg per pound) twice a day for 30 days prior to Immiticide treatment. At the same time, give normal monthly doses of Heartgard (ivermectin). Note that prednisone can help reduce the risk from Immiticide injections. Recommended dosage, to be started at the same time as the injections, is 1 mg/kg daily to start with, with decreasing dose over two to four weeks. See Consensus Treatment Recommendations for more information.

    If you elect to use the slow-kill method (no Immiticide), then I recommend giving normal doses of Heartgard (ivermectin) weekly along with pulsed doxycycline at the rate of 10 mg per kilogram of body weight (about 5 mg per pound) twice a day (see options for pulsing doxycycline below). This treatment should be continued for at least a year, or until the dog no longer tests positive for heartworms (note that a dog may test positive for up to six months after the worms are all gone).

    Remember that anything that increases your dog's heart rate increases the risk as long as your dog is infected with heartworms."

  • Xebby
    He's at my home now under strict confinement.  He will be getting his third spinal injection to treat the HW in a few days then go to his new home. 

    I believe that Xebby is referring to injections of Immiticide which are administered by deep intramuscular injection in the lumbar (epaxial) muscles - not actually into the spine.  Immiticide is melarsomine dihydrochloride (an organic arsenical chemotherapeutic agent).

    There were problems with a Immiticide shortage in 2011 due to manufacturing issues.  I don't know how completely that has been resolved. 

     

     

  • Bay
    The vet has put him on Doxycycline

    Please note that any dog (or person) on antibiotics should also be on probiotics given 2-3 hours before or after the antibiotics.  That helps to minimize the overgrowth of undesirable organisms in the digestive tract.

    Yes, antibiotics will kill a lot of the probiotics you give, but you just need to keep giving more. 

    Note:  Probiotics (bacteria) are responsible for a lot of the digestive processes within the intestines. 

  • Thanks so much, everyone, for your advice/info. I'm feeling a little better, at least now that I've gotten a better idea of how bad (or not too bad, as the case may be) his heartworms might be.

     

    janet_rose
    However, I don't understand his/her having a problem with Interceptor since that will not kill adult heartworms and (if the rescue was truthful) Henry shouldn't have much in the way of microfilaria.

    I think part of the reason why she wanted to take him off was because I didn't have a whole lot of info when she called last night (the rescue's paperwork was pretty basic), so I couldn't tell her what type of preventative they'd had him on or when the original negative test was given. I was able to talk to the rescue today and we'll be back at the vet Monday for more blood work, so I'll be able to fill them in then on everything I learned from the rescue today.

    My vet also mentioned the shortage of heartworm treatment available right now, but I told her I did want to proceed with treatment so she was going to try to hunt some down/get some ordered. Although, now hearing that it's so stressful for the dog makes me think I should go with the slow-kill method? It's difficult because I really want to do whatever's best for him, but I guess that's not really knowable until the vet gets a better idea of how bad everything is.

    janet_rose
    The worst problem you will probably have is keeping a 1-year-old Feist inactive.  He is not going to like that especially if he does not feel sick.  

     

    Ah, I can't even imagine keeping him inactive! He's a bit of a wild man when he's excited (which has been a good bit of time in this first week we've had him home, haha) and running and chasing are basically his favorite things ever. It's terrible to think that he's going to have to be confined for more than a month for recovery.

     

  • Xebby
    It is a very painful and long process, difficult on both the caregiver and the dog.

     

    Oh, this was what I was worried about. Especially the confinement part, because Henry is not going to be very good with that. He's basically just a ball of energy.

    Xebby
    Did the vet do a microfilariae test, looking at his blood under the microscope for the parasites that live in the blood?  It is usually recommended to follow up a positive test with a blood smear. It takes 6 months from the time the dog is infected to show up positive on a test.  That means he would have had to had HW for at least 6 months prior to his positive test.

     

    I'm not sure what test was done, exactly. I guess whatever further blood work they're doing next week will probably tell the vet...something. According to the rescue, he was about 6-7 months old when he came to the shelter (and at the time of the negative hw test), so that must mean he must have first gotten it when he was very, very young.

  • Bay
    Ah, I can't even imagine keeping him inactive!

    Well, you need to start thinking about how you are going to do!!  It is not optional during heartworm treatment.

  • janet_rose

    Xebby
    He's at my home now under strict confinement.  He will be getting his third spinal injection to treat the HW in a few days then go to his new home. 

    I believe that Xebby is referring to injections of Immiticide which are administered by deep intramuscular injection in the lumbar (epaxial) muscles - not actually into the spine.  Immiticide is melarsomine dihydrochloride (an organic arsenical chemotherapeutic agent).

    There were problems with a Immiticide shortage in 2011 due to manufacturing issues.  I don't know how completely that has been resolved. 

     

     

    Yes, sorry, that is what I ment, NEXT to the spin not in it.  There was a shortage and in 2011 and it was very very exspensive to treat HW beacuse of this. I remember last summer we had to wait a few weeks just to start treatment on a positive dog in the shelter because it was nearly impossible to get the immiticide. Thanks to a great program we have donations were able to cover the cost of the treatment.

  • Bay
    My vet also mentioned the shortage of heartworm treatment available right now, but I told her I did want to proceed with treatment so she was going to try to hunt some down/get some ordered. Although, now hearing that it's so stressful for the dog makes me think I should go with the slow-kill method?

    As I understand it the slow-kill method (and/or surgery) is the way to go with very bad heartworm infections where the dog would not survive the arsenic treatments -or- if there are no funds for the arsenic treatment.  I don't know the pros and cons for using the slow-kill method for very light infections which I suspect is what your dog has, but I would seriously explore the possibility.  However, the additional length of inactivity for such an active dog may make the slow-kill method worse overall than the arsenic treatment. 

    By the way you need to be sure that your rescue group understands that one heartworm test on a puppy last May is absolutely not adequate testing to OK a dog for adoption this much later.  He should have been retested about the first of this year.  Not having a second test (an antigen test) before you adopted Henry would speak to the competence of this rescue group. 

    If there was no second test, the rescue group could be considered responsible for paying for the heartworm treatment.  Whether or not they can afford it or whether you ask them to do so are separate issues.  If there was a second negative test (6-7 months after the first one) and the heartworm "preventative" simply failed (happens more often than a lot of people realize), the manufacturer of the "preventative" may be liable for the treatment costs. 

  • Bay

    My vet also mentioned the shortage of heartworm treatment available right now, but I told her I did want to proceed with treatment so she was going to try to hunt some down/get some ordered. Although, now hearing that it's so stressful for the dog makes me think I should go with the slow-kill method? It's difficult because I really want to do whatever's best for him, but I guess that's not really knowable until the vet gets a better idea of how bad everything is.

    Your vet is likely not going to want you to do the "slow-kill" method -- because it's not under his control.  The slow-kill method can be far far easier on the dog, but it's a bit work-intensive for you.  You have to understand how ivermectin works in the body and it's side effects to keep this safely under control during the whole treatment.

    (and I'm not screaming this but for lurkers -- you MUST MUST MUST be cautious with a herding dog and ivermectin -- in this case the dog has already been ON liquid ivermectin so he's not sensitive to it)

    In honesty -- it's not sounding *to me* like he COULD be very positive.  He's not old enough, first of all.

    **BUT I* WILL CAUTION YOU --

    He **will** have to be sedentary.  Absolutely with ANY treatment. 

    ANY of these treatments kill first the microfilaria but ultimately the adult heartworm are dying.  The trick of the immiticide is to only have "some" heartworm adults die at a time.  (you'll understand more in a minute).  With the slow-kill method you DO only kill the adults slowly - it takes repeated applications to kill ANY adults.

    Think of it this way -- adult heartworms look eerily like cooked spaghetti.  Now -- there can be a few or a LOT.  But feature -- if you will even a few strands of cooked spaghetti pasta in your hand.  Your hand is the "heart". 

     Now -- what does the heart do?  It beats -- OFTEN.  So -- feature that cooked spaghetti wadded up in your hand and now you squeeze your hand repeatedly (as the heart squeezes as it beats to shove blood thru the heart).  Imagine what you now have in your hand.  MUSHED cooked spaghetti?

    Except  remember now -- your fist is the HEART.  There is blood rushing thru that ALL the time.  So those pieces of mushed pasta?  They just got swept away by the blood rushing thru the heart. 

    THAT IS THE HUGE RISK -- when the adult heartworm DO die then, like **any** dead material, it begins to decompose.  And as that dead parasite weakens as it decomposes, the heart is going to mush it up as it beats.  And "chunks" of that parasite go sailing thru the bloodstream.  Those pieces can clog blood vessels, can cause a stroke, or just cost a myriad of problems in the blood vessels until the body is able to re-absorb all that junk.

    But with ANY treatment -- that period of them being sedentary?  it's CRITICAL because you have to give the body time to re-absorb all that dead parasite material and filter it away in small enough amounts so that the body can handle it.

    You likely will need to keep him on relaxants -- something like valerian root or passionflower even (not habit-forming) or perhaps tag team those with something like Hylands Calms Forte so you can keep him from climbing walls while he heals.

    You will become a pro at things like stuffing a Kong and freezing it so he has to work IN HIS CRATE to get his food out -- it will keep him occupied and give him some isometric exercise.  Think toys, etc. so he gets mental stimulation and something to "do" without him running around the house.  He will NOT be able to do that without risking a stroke.