They're tiny insects that can cause big problems. A rise in the number of ticks this year has infectious disease experts focused on the best way to treat the Lyme disease that the little buggers can spread.
Some 20,000 Americans are infected and treated every year, but countless others go undiagnosed. The illness has symptoms that include fever, fatigue and headaches, but if left untreated, Lyme disease can be more serious.
While there are physical symptoms of the disease that can include severe headaches, severe joint pain and even numbness in the hands or feet, many experts believe Lyme disease can rewire the human brain and affect personality.
"I'm convinced that Lyme in a chronic form can affect psychiatric issues, neurological issues and you can have neurological problems," New York epidemiologist Dr. Daniel Cameron said.
The Center for Disease Control and Prevention notes that up to 5 percent of patients "may develop chronic neurological complaints months to years after infection."
Lyme disease patient Kelly Kulesz told "Good Morning America" she saw herself change overnight because of her infection.
"They put me on stage fright medications," Kulesz said. "Doctors thought it was obsessive compulsive disorder, but it's just not."
When Terry Jo Sedlacek went to trial for allegedly gunning down the Rev. Fred Winters in March, the defense cited his Lyme disease infection and it's contribution to what many call "lyme rage."
But not all experts believe Lyme disease causes such " target="_blank">radical changes in personality.
"The example I like to cite is if I have Lyme disease and I get run over by a truck, the Lyme disease didn't cause my broken leg," Halperin, said Dr. John Halperin, lead author on the new American Academy of Neurology Guideline on Lyme Disease Treatment.
ABC News medical contributor Dr. Marie Savard, who had lyme disease, said that the possibility of personality changes should at least be taken into consideration.
"It does affect the central nervous system. You can have behavior changes, personality changes," she said. "We have to listen and pay attention."
More Information on Lyme Disease
For more information on how to prevent, diagnose and treat Lyme disease, vist the Web sites below.