Canine heartworm disease is once again on the minds of dog owners and veterinary healthcare teams in the Midwestern and western regions of the United States. For most owners, getting their dog tested and put on a heartworm preventative is a task set aside from March through September, depending on where they live. Unfortunately, the idea of a ‘heartworm season’ is no longer appropriate in these regions.
According to the American Heartworm Society, there has been a significant increase in canine heartworm disease in all fifty states, becoming more prevalent in the Midwestern and western regions over the last few years. What was once considered endemic to the southern and northeastern areas of the United States has now become a nationwide problem. There are several factors contributing to this shift.
Weather Changes
Climatic changes have produced summers that are more hot, winters that are more mild, and spring/fall seasons that fall back onto the warmer season rather than push forward into the colder one. This has allowed mosquitoes to flourish in environments where they would not normally survive. Heartworm larvae are able to develop in the mosquito when temperatures reach the upper 60’s to low 70’s.
Heartworm Positive Dogs
When puppy mills in heartworm endemic areas are closed down, and disasters such as Hurricane Katrina and Haiti hit, an influx of heartworm positive dogs are brought into the Midwestern and western states. This produces an increase in heartworm infection because mosquitoes feed on these heartworm positive dogs, ingest the larvae and transmit the infective larvae to dogs not on preventatives.
Increased Urbanization
Increased urbanization has caused some species of mosquitoes to migrate throughout the United States. This is due to the creation of more water drainage systems, buildings and asphalt. This combination produces heat that radiates throughout the night. The increased heat along with more landscaping promotes a mosquito friendly environment and thus an extended transmission period.
Due to the increase in heartworm infections everywhere, the American Heartworm Society recommends year round heartworm prevention for all dogs in all states. Dog and cat owners can discuss heartworm disease, testing, and prevention with their veterinarians to get more information. Year round prevention not only protects dogs from heartworm, but also prevents the transmission of zoonotic parasites such as hookworms, roundworms, and tapeworms from pets to people. Year round prevention is less costly then treatment, less dangerous than infection, and less frustrating than remembering the ‘heartworm season’.
Roberta Avila-Guevara - I have been an animal lover since I could walk. I attended the Bel-Rea Institute of Animal Technology to become a Certified Veterinary ...
