Eeeekkkk! Thank you for sending this fire 'n' brimstone email to me, B.J. This particular missive hasn't reached me, but it's obviously making the rounds quickly and it's guaranteed to send many dog owners into a state of panic.
Readers, the message that B.J. attached reads, in part, "Thousands of heartworm-positive dogs from Hurricane Katrina were shipped to shelters in Ontario. They were adopted out as quickly as possible in order to make room for more infected animals. If you adopted one of these dogs, or if your dog came in contact with one, inform your veterinarian immediately so heartworm treatment can begin.
"Heartworm is a deadly disease and it's estimated that one in four Ontario dogs will be infected by the end of this summer."
The person who started this email may have been sincere in his intentions, but as is often the case, the severity of the situation is grossly exaggerated.
Yes, heartworm is a growing problem throughout North America and Canada, particularly southern Ontario is seeing more cases.
In 2002, it was reported 268 Ontario dogs were infected. In 2006, Vita-Tech, a diagnostic laboratory, reported 272. I'm unable to find reliable current numbers, but as you can see, the incidence of heartworm appears to have been quite low in recent history.
However, keep in mind many other Ontario laboratories test for heartworm and their numbers were not included in the totals. Also, we don't know how many dogs died from the disease without diagnosis. Given the fact heartworm is pretty much epidemic in many southern U.S. states and the number of cross-border adoptions are increasing, it makes sense for us to be additionally cautious.
The email B.J. received mentions Hurricane Katrina dogs and it's true that thanks to dedicated rescue groups many of these dogs were removed from the area and subsequently adopted into Canadian homes, including a large number in southern Ontario.
The rescue groups provided a valuable service and it's assumed the dogs they saved were checked for heartworm and other problems in advance of adoption. Given the urgency of the situation, it's certain some dogs brought undiagnosed heartworm with them.
Also, as mentioned above, many dogs are now routinely adopted into Canada from other areas where heartworm is epidemic. The email leaves the impression Hurricane Katrina dogs are the sole reason why more Canadian dogs will be diagnosed in the years to come, but that's simply not true. All dogs, regardless of their origin, need to be tested for heartworm.
Heartworm is a blood parasite spread by mosquitoes when they bite an infected dog, then inject the immature worms into the next dog they bite. Unfortunately, diagnosis of heartworm disease is usually detected only after much damage to lungs and heart have already taken place. Advanced symptoms include listlessness, chronic cough, laboured breathing, and weight loss. Medication is available to kill heartworm in a dog, but it carries its own drawbacks. In short, this disease is easily prevented, but difficult, dangerous and expensive to treat.
In Ontario, heartworm prevention is given, following a blood test, from May through October in order to cover the months when mosquitoes are most prevalent. This year saw an early start to summer and continuing hot, humid conditions provide perfect breeding grounds for unusually high skeeter populations.
It's estimated 75 per cent of dogs in North America have never been tested or put on preventive products for heartworm. With that in mind, but without succumbing to "the sky is falling!" tactics of that email, it makes sense we begin taking heartworm disease more seriously.
Readers, if you haven't had your dog tested for heartworm this year, please do so as soon as possible. Preventive products are available and they're easily administered at home. Your veterinarian can give you all the information you need to help your dog stay healthy, happy and safe.
As a note, the jury is out when it comes to heartworm in cats. Apparently our feline friends can contract the disease, but not in the same numbers as dogs. And the preventive products, which are different than the dog variety, may not work as well for cats. A preliminary blood test to check for existing heartworm must be done for cats, just as it is for dogs. Consult with your veterinarian for more information.