By Chantel Lott

MISSISSIPPI STATE -- Mosquitoes may be a summertime nuisance to people, but their threat of transmitting heartworms to dogs is year round in Mississippi.

"Unlike the North, where it is common for dogs to be given heartworms prevention during the spring and summer and not in the winter, southeastern weather is not cold long enough to kill mosquitoes, which are heartworm carriers. This means that those who live in the Southeast should treat our dogs with heartworm protection all year long," said Dr. Cory Langston, clinical pharmacologist at Mississippi State University's College of Veterinary Medicine.

Mosquitoes transmit heartworms by taking blood from one heartworm-infected dog and injecting it into another dog. The juvenile heartworms transported by the saliva of the mosquito then multiply rapidly in the bloodstream.

"We worry about heartworms because the result of infection is a physical obstruction in the right side of the heart by ever increasing numbers of heartworms," Langston said.

The lungs are blocked as well, and in some cases the dog fatigues quickly in exercise or coughs. In a more advanced stage, the abdomen of the dog may swell due to fluid accumulation.

"If left undiscovered or untreated, heartworms can cause heart failure that means eventual death for the dog," Langston said.

Preventative medication is available in three types. One familiar product is commonly called Filaribits, which is a once- a-day pill for dogs.

"This is the oldest of the three commonly used treatments today, but the owners who use Filaribits find their dogs look forward to the pill as if it were a treat. However, if owners skip more than one day in treatment then the dog is at risk for infection," Langston said.

Several manufacturers produce a second treatment method under the common names Heartguard, Interceptor and Sentinel. These once-a-month treatments are the most widely used method.

Revolution, a once-a-month treatment placed on the back of the dog's neck, is a third method. The external option that Revolution offers may be an asset if the dog shows apprehension about taking pills.

"Don't confuse Revolution with treatments for fleas and ticks that are also placed on the back of the neck," Langston said. "Frontline and Advantage treat external threats fleas and some parasites, but not heartworms."

A short test detects a dog's heartworm infection and is available at the local veterinarian.

"We recommend that all dogs be placed on routine preventative measures beginning with the first shots at 6 weeks of age," Langston said.

For dogs 6 months and older, an initial test should be run to declare the dog clear of heartworms before beginning preventative treatment. For adult dogs just beginning preventative medications, even if the initial test is negative, another test should be run in six months to detect developing forms of heartworms. Unfortunately, most heartworm cases are due to human error.

"Sometimes dog owner's forget or neglect to give the medicine on time or on a regular basis, and for this reason we recommend an annual heartworm test, even though the preventatives are very effective when administered properly," Langston said. "If a heartworm infection is discovered, treatment should begin immediately as advised by the veterinarian."

Cats can also become infected with heartworms, although they are not considered the natural host to heartworms. A severe infection to a cat is as few as one to three worms because as an unnatural host, the body's inflammatory reaction to this parasite is more severe.

"Do not use the same treatment for your cat and your dog. It should be a different strength designed specifically for a cat by weight," Langston said.

Contrary to popular belief, studies have shown indoor cats to be just as likely to become infected by heartworms. While the preventative, Heartguard for cats, is not a routine recommendation, it is available for those owners wanting to protect their cat from this relatively rate but very serious disease.

Contact: Dr. Cory Langston, (662) 325-1265