How to Detect Heartworms in Dogs

Heartworms infect dogs in almost every area of the U.S. From 2001 to 2007, the incidence in nine states that had minimal infections increased to cover most of each of the states. According to the American Medical Veterinary Association (AMVA), any dog that is exposed to mosquitoes even briefly should be tested. Protecting your dog from getting heartworm disease is important. However, if you have missed medications or acquire a dog, detecting heartworm can save its life.

Instructions

    • 1

      Observe your dog for heartworm symptoms. According to the AMVA, dogs may show no sign of heartworms during the first two stages of infection. Later signs include coughing, fatigue, loss of appetite and labored breathing, as the worms affect the heart and lungs. Treatment is required immediately, as your dog can die once symptoms appear. According to Wayne Crans, an associate professor in entomology, some dogs do not have symptoms until the disease has progressed too far for treatment.

    • 2

      Take your dog to your veterinarian for laboratory testing. According to Crans, only your veterinarian is qualified to diagnose heartworms. A yearly blood test for a dog that is not on heartworm prevention will generally detect heartworms that are in early stages, according to Crans.

    • 3

      Ask your vet to examine a blood smear if your dog has symptoms and could have large numbers of heartworm microfilariae present. This method is not good for early detection but may be a cheaper and faster method when heavy infestation is suspected. If the result is negative, more sensitive testing is required, according to Marvistavet.

    • 4

      Use a larger sample of blood to perform the DIFIL, or Knott's test. According to Marvistavet, the use of a centrifuge or filtration in these tests permits your veterinarian to detect lower numbers of heartworm infection. This test may show positive for more than just heartworms.

    • 5

      Ask your veterinarian to perform an antigen test for heartworms. This test can detect even a small number of female heartworms and can determine if a positive DIFIL or Knott's test is heartworm or another infection.

    • 6

      Discuss antibody testing with your veterinarian. Antibody testing can detect both male and female heartworms and can detect them earlier.

    • 7

      Do further testing, if necessary. According to the AMVA, testing such as chest X-rays and a heart ultrasound may be necessary to determine the extent of heartworm infection.