Bites and Strings Bites and Strings
National Institute of Allergy and Infectious Diseases
Tickborne diseases are becoming a serious problem in this country as people increasingly build homes in formerly uninhabited wilderness areas where ticks and their animal hosts live. Tickborne diseases can be caused by viruses, bacteria, or parasites. Most people become infected through tick bites during the spring and summer months.
Rocky Mountain spotted fever, a bacterial disease transmitted by the dog tick, was first identified in 1896. It still exists, although now it can be easily treated. Since then, researchers have identified many new tickborne diseases.
Tickborne diseases can be found throughout the United States. For example, Lyme disease, first discovered in Connecticut in the early 1970s, has since spread to every state except Hawaii.
One of the newest tickborne diseases to be identified in the United States is called Southern tick-associated rash illness (STARI). This disease has a bull’s-eye rash similar to that found in Lyme disease, which is caused by bacteria transmitted by the deer tick. Although researchers know that the lone star tick transmits the infectious agent that causes STARI, they do not yet know what microbe (germ) causes it.
Ticks transmit ehrlichiosis and anaplasmosis, both bacterial diseases. Babesiosis is caused by parasites carried by deer ticks. These diseases are found in several states.
Tularemia, a less common tickborne bacterial disease, can be transmitted by ticks as well as other vectors (carriers) such as the deerfly. Public health experts are concerned that the bacterium that causes tularemia (Francisella tularensis) could be used as a weapon of bioterrorism.
Tickborne disease can usually be prevented by avoiding places where ticks often live, such as dense woods and brushy areas. Using insect repellents containing DEET (for the skin) or permethrin (for clothes), wearing long pants and socks, performing tick checks, and promptly removing ticks also will help prevent infection from tickborne microbes.
Scientists are searching for better ways to diagnose, treat, and prevent tickborne diseases. They are also looking for ways to control the tick populations that transmit microbes.