Heartworms are invasive parasites that can make your dog very ill and if untreated, they could kill your dog. The heartworm larvae can be transmitted to your dog via a mosquito that has bitten an infected dog. When this mosquito bites your dog it transmitted the larvae to your dog. As the larvae grow and mature into adult worms, they can clog your dog’s blood vessels, lungs, and heart. This can cause respiratory and circulatory issues. There are treatments for heartworms but they are often invasive, expensive and may not return your dog to good health. Fortunately, there are preventative medications you can give your dog. These medications are available by prescription and must be given monthly all year round since just a few warm days can make mosquitoes active. Your dog will need periodic blood tests to ensure he hasn’t inadvertently been exposed to heartworms. Learn more from your animal hospital Los Gatos, CA veterinary clinic.