Most pet owners have heard of heartworm disease, but what many don't realize is that the cause of heartworm disease starts with a simple mosquito bite.  Heartworm disease is more prevalent in dogs than cats, but both can contract the disease.  
 
Transmission:  The disease is not directly transmitted from dog to dog, cat to cat or to humans. Heartworms can only be transmitted from animal to animal by mosquitoes.  When a mosquito bites an infected animal, young heartworms called microfilariae enter into that mosquito's system. Within two weeks, the microfilariae develop into infective larvae inside the mosquito; these infective larvae can be transmitted to another animal when this mosquito takes its next blood meal.*
 
Heartworm Disease:  The infective larvae mature into adult heartworms in approximately six months.  The worms damage the blood vessels, and reduce the heart's pumping ability, resulting in severe lung and heart disease, and eventually death.   Heartworm disease is treatable, but expensive.  Animals typically have a full recovery from the disease once treated, but they continue to be susceptible unless a monthly heartworm preventative is given.  
 
Prevention:  The cost to prevent heartworm is much more affordable than treating the disease, not to mention the best thing for your pet!  Heartworm preventatives may be purchased from your veterinarian or variety of other sources and should be given to your cats and dogs monthly.
 
The Humane Society sees so many dogs pass through our doors with heartworm disease.  It's a painful and deadly disease that can be completely avoided with monthly heartworm preventative.  If your pet is not currently on a preventative, please make an appointment with your veterinarian so your pet can be tested for the disease.  It is important to ensure an animal doesn't currently have the disease before a preventative is started.
 
*Source: American Veterinary Medical Association