April: Dedicated Heartworm Awareness Month – Protect Your Pets Today

When I was in college I had to dissect a cat (I know…).  One thing that helped me get through it was the fact that they weren’t healthy cats who were killed for college dissections.  They came from the local animal shelter, and either passed, or were put down, due to medical issues.  My cat, as I quickly discovered, had passed away most likely from complications due to heartworms.  It’s one thing to see a picture of an animal’s heart infested with worms, and quite another to see it in person.  Probably thanks, at least in part, to that experience, I’ve never felt comfortable forgoing heartworm prevention when it comes to my own pets. 

April is National Heartworm Awareness Month.  I know, at this point, April is already almost over – but it’s not too late to get proactive about our pets’ health!  Did you know that not only can dogs get heartworms – but cats, and ferrets can too?  Other animal species such as coyotes, wolves, foxes, sea lions and, very rarely, humans, can carry heartworms as well.

As their name suggests, heartworms are long, often described as spaghetti like (if that doesn’t put you off eating spaghetti…) worms that can infest the heart, lungs, and blood vessels.  Heartworms can be fatal, but short of killing our beloved pets they can also cause heart failure, organ damage, and lung disease.

Dogs are a natural heartworm host.  Inside a dog, heartworms are able to mature and reproduce.  That means that in dogs, if left unchecked heartworm numbers will steadily climb.  The same is not true of cats.  Cats are considered to be atypical heartworm hosts meaning that, in cats, heartworms do not commonly mature and reproduce.  That doesn’t mean, however, that they can’t still cause life threatening complications such as a condition known as heartworm associated respiratory disease.  The treatment commonly given to dogs to eliminate heartworms is toxic, and cannot be used, in cats.

Signs of heartworm infestation in dogs include a mild but persistent cough, fatigue and reluctance to exercise, decreased appetite, and weight loss.  Symptoms will progress if heartworm remains untreated, and could eventually include symptoms of heart failure, and fluid accumulation in the abdomen.  In some cases, heartworms can cause blockages in the heart which can quickly become life threatening.  Symptoms in cats can be similar to those in dogs, including coughing, lack of appetite, and weight loss.  Sometimes more dramatic symptoms such as vomiting, difficulty walking, fainting, seizures, and fluid accumulation can occur.

Ok, so heartworms suck, but how do pets get them in the first place?  Basically, heartworms are transmitted by mosquitoes.  Female mosquitoes can carry microfilaria, or baby heartworms, that they pick up when biting a heartworm infested animal.  These microfilaria develop into larvae inside the mosquitoes and are then passed on to new animals when the mosquitoes feed again.  It takes up to 6 month for these larvae to mature inside their new hosts.  Mature heartworms can live 5 to 7 years in dogs, and from 2 to 3 years in cats.

What can pet owners do to protect against heartworm?  If you take your dog in for regular yearly vet exams, you’ll probably be familiar with heartworm testing.  This is an important yearly test, because the earlier heartworm is detected the better your pets’ prognosis.  Your vet will use a small amount of your dog’s blood to look for heartworm proteins.  These tests can direct the presence of heartworm often even before your pet begins to show any symptoms of infestation.  Testing in cats is not quite as straightforward, because cats are generally less likely to be carrying adult heartworms.  Your vet may use different tests, such as an antigen and antibody tests.

Puppies under 7 months old, and older dogs who test negative for heartworms can be started on heartworm prevention.  Preventives come in the form on spot-ons, injections, or pills.  All forms of preventatives work by killing heartworm larva before they get the chance to mature.  This is why it’s important to adhere to a schedule when it comes to administrating heartworm preventatives.  Once the worms molt past the larval state it’s much less likely they’ll be affected by preventatives.

Annual testing, even if your pet is on year round preventative, is important.  Something as simple as missing one dose of preventative can lead to heartworm infestation.  Even for owners who adhere to their pet’s preventative schedule, it’s possible for pets to sneak off and spit out, or vomit, their pill.  Preventatives are not always 100% effective.

Despite that, using preventatives are generally much safer, and cheaper, than heartworm infestation and treatment.  According to the Companion Animal Parasite Council 166,817 dogs tested positive for heartworm last year.  Cases were reported in all 50 states.  Don’t let your pet become a statistic – talk to your vet about what they recommend as heartworm preventative for your area.  April, Heartworm Awareness Month, may be almost over, but it’s not too late to be proactive about your pet’s health care, if you haven’t been already.

We always love hearing from our readers, comment below!  Do you currently use heartworm preventative for your pet(s)?