Heartworm is a highly preventable disease that can occur in your dog. Once contracted it is difficult and expensive to
Cause: The cause of heartworm is the mosquito. If there are mosquito's around, even if you live in a desert region,
there is a chance that your pets will get heartworm.
Transmission: The transmission of Heartworm to your pets is through the bite of a mosquito. When a mosquito is
taking a blood meal from an infected dog, it will picks up the microfilaria (baby heartworm.) Within the mosquito, the
microfilaria will then go through their life-cycle to the infective stage. After this they can infect other animals.
Life Cycle: Adult heartworm are found primarily in the right ventricle and adjacent vessels of a dogs heart. Here they
produce larvae called microfilaria, a microscopic creature that circulates through the dog's blood vessels until they
are once again picked up by a feeding mosquito.
Once in the mosquito, the microfilaria will develop into their second and third stages taking any where from within 14
to 21 days. The third stage is the larvae that is then re-deposited in the dog during a mosquito bite (feeding).
The larvae then migrates to the fat or muscle cells in the subcutaneous tissues. There they mold again to the fourth
and fifth larval stages. In three months they begin to migrate to the right ventricle of the dog's heart where they finish
maturing. Female heartworm then begin to produce a new population of microfilaria about six to seven months after
the initial infections.
Symptoms: A dog may have heartworm disease for six months and an owner will not know he has it as the symptoms
may be very subtle. Since the disease affects the heart, lungs, kidney or liver, your dog may have low tolerance for
exercise, loss of appetite, listlessness, persistent coughing and difficulty breathing even while resting. Other
symptoms may include vomiting, diarrhea, yellowing of the gums and eyes (jaundice).
Once symptoms are present, the disease has advanced to the point where successful treatment is reduced and
death is possible. Consult your veterinarian if you suspect your dog to be infected.
Treatment: It is recommend dogs be tested annually for heartworm. There are two types of heartworm medicine
available for dogs, the daily dosage and the monthly dosage. Daily preventatives have an active ingredient of
Diethycarbamazine (DEC) and come in chewable, pills and liquids. Treatment should be started one month prior to
mosquito season and given daily to two months after the last exposure to mosquitoes. Monthly heartworm
preventives are Ivermectin (Heartgard) and Milbemycin oxime (interceptor).
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