Assessing Your Dog’s Risk

How do you know if your dog is at risk of contracting Heartworm Disease?  Well, simply put – there is no magic 8 ball that can tell you accurately, what your pet’s risk level is. Here are the facts about what needs to happen for your pet to contract Heartworm Disease. Any combination of these risk factors mean you need to be proactive about testing your dog – every 6 months if you are not going to use a preventative – and at minimum, once a year and using a preventative is also important. In the US, Heartworm Disease has been reported in all 50 States (although it is more prevalent in warmer areas along the gulf coast and warmer areas) and all over Canada as well. If you live in a tropical climate – your risks are greatly increased.

  • A mosquito must bite a dog infected with Heartworm Disease (with a positive Microfilariae count)
  • That mosquito must then bite another dog to infect it with the disease
  • In order for the HW cycle to develop, the temperature must remain over  57 degrees F throughout this period. In general, it takes a few weeks. The process goes faster in warmer weather.
  • When a dog is bitten by an infected mosquito, the L3 is not deposited directly into the dog’s bloodstream. Instead, it is deposited in a tiny drop of mosquito “spit” adjacent to the mosquito bite. For transmission to occur there must be adequate humidity to prevent evaporation of this fluid droplet before the L3’s can swim through the mosquito bite and into the new host.
  • In the newly infected dog, it takes about 6 to 7 months for the infective larvae to mature into adult heartworms.
  • Stray and neglected dogs and certain wildlife such as coyotes, wolves, and foxes can be carriers of heartworms.
  • Mosquitoes blown great distances by the wind and the relocation of infected pets to previously uninfected areas also contribute to the spread of heartworm disease.

The bottom line here is – you must assess your dog’s risk based on the above conditions and decide what is right for your pet. Should you choose not to use a preventative (I recommend using the natural preventative discussed on the Treatment page), then you MUST be diligent in having your dog tested yearly, or ideally bi-annually to ensure your dog is not infected. Prevention is the best treatment!