Cats and heartworm disease:  A story you may not have heard

Mosquitoes don't discriminate.  They bite you, they bite your cat.  But when they sink their teeth into your feline friend, they might cause more than an itch.  Mosquitoes can transmit heartworm larvae to cats.  If these microscopic larvae settle in cats' lungs, they can cause big health problems.  There's no cure for feline heartworm disease, but it is 100 percent preventable.  Read below to learn more, then talk with your veterinarian about which prevention method is best for keeping your cat and its ticker heartworm-free.

Do cats really get heartworms? 

Heartworms aren't just a dog problem. A Texas study conducted in the late 1990's found that 26 percent of cats had contracted heartworms at some point in their lives. And remember, those pesky mosquitoes will bite any animal regardless of whether its tail wags or flicks.

Just how do mosquitoes transmit heartworms to cats?

Mosquitoes are carriers of heartworm larvae.  When a mosquito bites a cat, the larvae enter the cat's system through the bite wound.  When these larvae develop into adult heartworms, they eventually die and cause severe heart inflammation that can be fatal.  Even though the presence of adult heartworms is potentially deadly, the little larvae can be even more problematic.  Most larvae don't make it to adulthood in cats, which means they die in the cat's lungs.  The irritation leads to heartworm-associated respiratory disease (HARD).  Studies show that 50 percent of cats infected with heartworm larvae have significant disease in the arteries that supply blood to their lungs.  To lean more about HARD, see "Heartworms Can't Hide," below.

My cat doesn't go outside, so I don't need to worry, right?

Wrong.  Indoor cats are at lower risk for heartworm disease than outdoor cats, but there's no guarantee a mosquito won't buzz into your house through an open door or window - and it only takes one bite to do the damage.  A North Carolina study reported that 28 percent of cats diagnosed with heartworm disease were inside-only cats, so prevention products are smart to use in indoor cats as well as free-roamers. 

Mosquitoes aren't common where I live. Does my cat need prevention? 

Yes.  Cases of feline heartworm disease have been reported in all 50 states.  The occurrence of heartworm disease is markedly lower in some states, but mosquitoes are resilient little fellas and they're showing up in more and more places.  And don't forget that the game changes when you travel.  Anytime you pack your cat's bags, especially if you're heading to lake or coastal regions, you need to arm him with heartworm prevention.

OK, so my cat needs heartworm prevention.  What does it involve? 

The good news is that heartworm prevention products are some of the easiest to use, least expensive, and most effective items on the market.  Your veterinarian knows all about these products and will help you decide which one is right for you and your cat.

Heartworms can't hide.

Heartworm larvae are virtually invisible, but if your cat is infected with them, they'll show themselves.  Most cats with early-stage disease experience heartworm-associated respiratory disease (HARD) signs.  Rather than affecting the heart, the larvae affect the lungs and cause breathing problems often mistaken for asthma or allergic bronchitis.  If your cat exhibits any signs of HARD, which are listed below, schedule an appointment with your veterinarian.

• Coughing
  
• Panting
  
• Open-mouthed breathing
  
• Rapid breathing
  
• Gagging
  
• Appetite loss
  
• Weight loss
  
• Diarrhea
  
• Fainting
  
• Lethargy

***This has been adapted from information provided by the American Heartworm Society and KNOW Heartworms.  Visit knowheartworms.org to learn more.