Not only are mosquitos a nuisance in the summer in Florida but they can spread disease to pets too. The most notable disease dogs can get from mosquitos is heartworm disease. The good news is this is easily preventable with a monthly medication.
The reason it is important to test your dog yearly for heartworm disease is because the preventive pill is not 100%. There is resistance developing to some strains of heartworms. If heartworm disease is detected early it can be treated successfully. If it is not identified until symptoms appear it can cause permanent damage to the heart, lungs, blood vessels, and other organs and lead to heart failure and death.
By the time a dog is infected with heartworms it takes 6 months for the parasite to develop into an adult. The heartworm test will be negative until about 6 months after the infection.
Cats can get heartworms too but they are an atypical host so most heartworms do not survive to the adult stages. The immature worms can cause damage to the lungs, a condition call Heartworm Associated Respiratory Disease. Coughing, respiratory difficulty, collapse, and sudden death all can occur. Medications used to treat heartworms in dogs cannot be used in cats so monthly prevention is the only means to protect cats.
Heartworm prevention medication also prevent against intestinal parasites such as hookworms, roundworms and depending on the product whipworms. Some of these intestinal parasites pose a risk to humans especially small children so prevention is important.