Heartworm is caused by a parasite (Dirofilaria immitis) which is transmitted by mosquitoes and has the potential to cause heart failure and death. Your pets do not have to come into contact with other animals to develop this disease.
It may only take a single bite from a carrier mosquito to infect your cat. The parasite larvae move through the tissue beneath the skin. These larvae then migrate to the heart and adjacent blood vessels of the lungs where they grow into adult worms.
In the early stages of heartworm infection there may be no outward signs of disease.
Heart worm prevention is recommended for all cats and can be in the form of tablets or spot on medication given monthly for life.