With a simple mosquito bite larvae or microfilariae transfers into the animal's bloodstream. In a process that can take 6 months, the larvae matures, and then finds its way to the infected animal’s heart. By mating the adults continue the cycle, which can result in heart and lung disease for the host animal. Mosquitos can flourish in warm weather making many Australian pets high risk candidates for insect bites.
Although heartworm is more common in dogs than in cats the feline species can still contract the disease. The unfortunate side affect of this misconception is that many cat owners are not aware of the acute dangers heartworm can have for their felines.
One reason dogs have a greater risk of contracting heartworm is that a cat's immune system is extremely good at defending itself against heartworm larvae.
A cat's immune system naturally attacks heartworm larvae meaning it does not have the opportunity to grow and infest other parts of the cat's body. The problem with this is that if a cat does have heartworm proteins—that alert vets to the presence of heartworm in the blood stream—are often absent, which can mean an infected cat’s condition goes undetected until it is too late to act.
Surgery to remove heartworm from an infected cat is dangerous and often impossible. There is no current approved treatment for the removal of heartworm in cats making preventative measures—such as heartworm tablets and spot-on applicators—one of the only defences against the disease.
While there is a large market for dog heartworm preventatives the market for feline equivalents is considerably less. Administrating cat tablets and other treatments can also be difficult for owners. Unlike dog heartworm treatments those for cats are usually difficult for the unwilling cat to swallow, and are usually unpleasant in appearance and odour.
Due to the difficulties and lack of options available to cat owners vets recommend routine examinations, consultations with a regular vet, and taking the time to observe your pets.
Symptoms can present in cats in the following ways:
• Increased thirst.
• Respiratory distress such as coughing or difficulty breathing.
• Weight loss.
• Sudden collapse.
Vets can assist not only in the administration of heartworm preventatives, but can complete tests to ensure a cat has not been infected. While a blood test can prove ineffective vets can complete x-rays and ultrasounds instead.
Hopefully with time researchers can achieve a better understanding of heartworm in cats, and create better products and methods for not only preventing but treating the disease. For now at least it is the cat owners vigilance that will best protect their pets against heartworm.