The Companion Animal Parasite Council (CAPC) issued its latest Top 10 Cities Monthly Heartworm Report. The CAPC’s monthly reports summarize the metro areas across the United States that experienced the greatest percentage increase in positive heartworm disease tests during the month.
“It’s not about which state has the highest amount of heartworm prevalence in the United States,” says Craig Prior, B.V.Sc., C.V.J., immediate past president of the CAPC. “We know that’s the Southeast states, like the Mississippi Delta and Texas, and places like that. What we’re looking at what is the highest increase change in prevalence for that month because that means there is something going on. This about someplace like Fargo, N.D., or somewhere in the Midwest or Northeast, that has gone from, historically, 5 cases a month and has jumped to 20 cases. What’s going on there?”
There are mainly two factors that can contribute to a metropolitan area seeing a spike in animals testing positive for heartworm disease — microclimates and massive numbers of dogs traveling from one region of the country to another, says Craig Prior, B.V.Sc., C.V.J., immediate past president of the CAPC.
Mosquitoes can survive winters as they live in “microclimates” in the north (inside sewers, stormwater drains, crawlspaces and alleys).
“People think that it’s the middle of winter and their pet is not at risk,” says Prior, B.V.Sc., C.V.J., immediate past president of the CAPC. “With mosquitoes, it’s all about microclimates. It can be 30 degrees out and there can be mosquitoes everywhere. They can thrive very well and continue to spread disease. Clients need to understand that and the need for their pets to be on year-round heartworm protection.”
The other factor is the mass movement of dogs that’s been occurring in recent years in the U.S. The report pointed to a APPA (American Pet Products Association) statistic that shows 37% of pet owners travel with their pets. In addition, heartworm-infected shelter/rescue animals are being transported for adoption without being screened.
“A lot of these rescue/stray dogs are not being tested for heartworm,” says Prior. “And if they are, they are not being necessarily treated for heartworm. It may be weeks, it could be months, it could be a year before they get to a veterinarian. And a huge percentage of these dogs are heartworm positive. And that dog that’s heartworm positive is bitten by a mosquito, and the average mosquito’s range can be anywhere from 150 yards to a couple of miles. And that mosquito is now spreading heartworm. So we’re suddenly seeing a bump in heartworm prevalence in places like Denver and the Northeast and it’s because of the movement of dogs.”
The report is a stark reminder that it takes only one heartworm-infected pet in an area to become a reservoir of infection, increasing the number of infected mosquitoes and spreading the heartworm parasite to unprotected dogs and cats.”
Founded in 2002, the CAPC is an independent, nonprofit organization that is dedicated to increasing awareness of the threat parasites present to pets and family members. By generating and disseminating credible, accurate and timely information for the diagnosis, treatment, prevention and control of parasitic infections, CAPC works to educate pet owners and veterinary professionals.
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Download a client handout on the importance of preventing heartworm in cats.
Download a client handout on the importance of preventing heartworm in dogs.