Heartworm Disease:  Prevention

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                      General Information



Highly effective medication is available to prevent heartworm

disease.  Mosquito control is certainly helpful but should never

be the sole means of prevention.



                     Preventive Medication



1.  Diethylcarbamazine:  This drug has been available for many

    years for heartworm prevention, and its effectiveness is

    proven. It is available as a liquid, plain or coated tablets

    and chewable tablets.  It should be given daily starting 30

    days before exposure to mosquitoes and continued for 60

    after the last mosquito exposure.  In addition to heartworm

    prevention, the drug also prevents intestinal infection with

    roundworms (ascarids).  Diethylcarbamazine is also available

    in combination with other drugs to prevent heartworm,

    roundworm and hookworm infections.



2.  Ivermectin:  This drug was recently approved for treatment of

    heartworm infection.  Ivermectin is available in tablet form.

    Its main advantage is that it only needs to be given once

    monthly. At the approved dose, the drug does not prevent

    roundworms or other parasites.  Because the drug kills

    microfilariae acquired during the previous 30 days,

    administration should start within 30 days after the first

    exposure to mosquitoes and end within 30 days after the last

    exposure to mosquitoes. 



3.  In geographic areas where mosquitoes are present throughout

    the year, dogs must be treated year round to prevent

    heartworm infection. 



                 Important Points in Treatment 



1.  Heartworm preventives must not be given to dogs harboring

    microfilariae.  Your dog must be blood tested before starting

    the preventive medication. 



2.  Weigh your dog monthly during the treatment period.  A change

    in your pet's weight might require a change in dosage. 



3.  If you give the drug in your pet's food, mix the medication

    in a small amount of food and give this first.  If you mix

    the medication in a whole bowl of food, your pet may not eat

    everything and you will not know if the proper dose was

    given. 



4.  These drugs must be given on the prescribed schedule to be

    effective.  You must not skip doses.  Call the doctor if you

    are having trouble adhering to the prescribed schedule. 



                       Mosquito Control 



    * Screen outdoor kennels, especially in areas where heartworm is

    prevalent.



    * Keep your pet indoors during the early morning and evening

    hours, when mosquitoes are most active.



    * Electronic insect killers can be positioned near kennels.

    Premise sprays are available for treatment of the

    environment.



    * Mosquito repellents can be used for short periods of exposure.

    Be sure your pet does not lick off the repellent.