Other Tick-Borne Diseases
Worldwide, there are about 850 tick species and 30 major tick-borne diseases; the U.S. alone has 82 species of ticks collectively causing 10 major diseases listed below (eight are currently detailed on this website):
Lyme Disease
Ehrlichiosis
Anaplasmosis
Babesiosis
Tick Paralysis
Tick-borne Relapsing Fever
Tularemia
Rocky Mountain Spotted Fever
Colorado Tick Fever
Southern Tick Associated Rash Illness (STARI)
New tick-borne diseases continue to be discovered. For example, anaplasmosis (Human Granulocytic Ehrlichiosis) was first described in 1994; a Lyme disease-like illness has recently been reported in Missouri that does not test positive on standard Lyme disease serologic tests and is thought to be transmitted by the Lone Star tick; and an encephalitis-like virus was discovered in 1997 in several deer ticks (Ixodes scapularis) in New England. Some researchers suspect that there are even more tick-borne diseases that are still unidentified.
The exponential increase in deer numbers throughout the United States from an estimated 500,000 in 1900 to 30,000,000 today has greatly increased the number of deer ticks throughout the country. Increased outdoor recreation, extended forest cover (especially in the Northeast), reduced hunting in some areas and continued suburban sprawl are some of the factors involved in the rise in reported cases of Lyme disease and other tick-borne infections in humans throughout the United States.
In addition, pets, livestock and wild animals may succumb to certain tick-borne diseases, such as "cattle fever." Although the tick species which carry this disease have been eradicated from the United States, they are continually being reintroduced into Texas across the Rio Grande from Mexico. It has been estimated that an uncontrolled outbreak of these ticks in the U.S. could result in the death of up to 50% of all U.S. cattle herds (USDA-ARS).
