Here in the Northeastern United States, warmer weather means mosquitoes. The buzz around mosquitoes occurs because mosquitoes transmit heartworms. Dogs become infected with heartworms when an infected mosquito bites a dog. Heartworm larvae migrate through the skin homing in on the blood vessels of the lungs. Here the heartworms mature and reproduce, clogging pulmonary vessels and extending into the heart. Adult heartworms send millions of microfilaria into the blood, microfilaria which infect mosquitoes feeding on an infected dog and which can ultimately infect another dog.

Widespread Distribution

Heartworms have been diagnosed in all 50 states. While most dog owners associate spring with heartworm testing and prevention, heartworms can be transmitted year-round. Because global warming and urban sprawl have created mosquito-friendly environments, mosquito populations now thrive year-round.

Annual Testing

The American Heartworm Society recommends annual testing of all dogs for heartworm disease. Annual testing allows detecting of a heartworm infection before the onset of clinical signs, when the disease can most easily be treated. Two types of heartworm tests are available. One examines a blood sample under the microscope, looking for the presence of juvenile heartworms. The other test identifies substances in the blood resulting from the presence of adult female heartworms. This is the common screening test used in your veterinarian’s office, but to make a diagnosis of heartworm disease, both tests are used in tandem.

Year-Round Treatment

Both the Companion Animal Parasite Council and the American Heartworm Society recommend year-round heartworm treatment for all dogs. Year-round treatment increases compliance and improves protection. First, you don’t have to remember when to start and stop the medication because it is given every month. Second, if you decide on the spur of a moment to travel with your dog, you don’t have to worry about heartworms wherever you are going since your pet is already on a monthly schedule. Finally, monthly heartworm preventatives have the added benefit of controlling intestinal parasites.

Preventing Heartworms in Your Dog

• Give the preventative on schedule at the dosage prescribed by your veterinarian.
• Check the heartworm preventative’s website for a widget to remind you when it’s time to give the next pill.
• Limit your dog’s exposure to mosquitoes by keeping them inside at dawn and dusk when mosquitoes are most active.
• Discuss mosquito repellent products like Insect Shield with your veterinarian.