Everyone—in the United States and around the world—is vulnerable to diseases spread by infected insects like mosquitoes, ticks and fleas, also called vectors. Vector-borne diseases are human illnesses caused by parasites, viruses and bacteria that are transmitted by vectors. Increasing global travel and urbanization are contributing to vector-borne disease outbreaks in new regions and countries. 

Some vector-borne diseases, like plague, have been around for thousands of years. Others, like Heartland virus disease and Bourbon virus disease, have been discovered recently. The most common vector-borne disease in the United States is Lyme disease, which is transmitted by blacklegged ticks and is estimated to cause more than 400,000 new cases each year (source: Data and Surveillance | Lyme Disease | CDC)