Uptick in Lyme disease still leaves many undiagnosed, experts say
Published: Thursday, December 5, 2013 at 5:57 p.m.
Last Modified: Thursday, December 5, 2013 at 5:57 p.m.
Matthew Weldon, the director of mosquito control for Levy County, held a folder full of medical files -- of neighbors and family members who he claims have Lyme disease, even though they haven’t been diagnosed with it.
Weldon, who spoke Thursday with specialists at the Tick-borne Disease Symposium held at the University of Florida’s Emerging Pathogens Institute, is representative of hundreds and even thousands of people in Florida who have Lyme disease symptoms without the diagnosis. Weldon says he, too, exhibits some of these symptoms.
That quandary is at the center of a controversy over what defines the disease and how it’s tested. Those are particularly sensitive issues in the Southeastern part of the U.S., where
disease incidence is much lower than in the Midwest and Northeast.
That’s at least in part because the tick that typically carries the pathogenic strain causing Lyme disease is more abundant up North, and the northern tick itself behaves differently from ticks in the South, said Dr. Paul Mead, the chief of epidemiology and surveillance activity at the division of vector-borne diseases at the Centers for Disease Control and Prevention.
Mead spoke at Thursday’s symposium, explaining that the transmitting tick, ixodes scapularis, commonly known as the black-legged tick or deer tick, is less likely to bite people in the South and that the ticks are also less likely to be infected with the Lyme-causing pathogenic strain.
At the same time, the incidence of Lyme disease throughout the country -- especially in the Midwest and the Northeast -- has grown steadily since the first documented case in 1975 in Connecticut.
“Lyme disease truly is a major public health problem in the U.S.,” Mead said. “The increase is probably not due to better reporting but true increases in Lyme disease.”
Mead said that while the reasons for the increase are not entirely known, the reforestation of parts of the country as people moved to urban areas has caused the deer population to increase, and deer ticks can carry Lyme disease.
Along with urbanization, there’s been a trend for people to move back to the country, in wooded areas, Mead continued, so they are more at risk of contracting the disease.
In the South, however, those same trends have not been confirmed.
Although the incidence of Lyme disease has increased in Florida, some experts think that most cases involve people who were infected in other states.
“When we tease it apart, we don’t verify local transmission in the vast majority of cases,” said Carina Blackmore, the deputy state epidemiologist with the Florida Department of Health.
Blackmore added that most cases occur in adults during the summer.
For Dr. Kerry Clark, however, the South has thousands of cases that go undiagnosed. Clark, a public health professor at the University of North Florida in Jacksonville, said hundreds of people with Lyme disease symptoms have contacted him for help, including Weldon. They are the “Holy Grail” of evidence that the disease is born locally, since none could have contracted the disease out of state, Clark said.
“The symptoms are consistent, many with heavy tick exposure,” Clark said. “I don’t think it’s logical to say that it’s something else.”
Yet many people with persistent symptoms, such as fatigue, headaches and the tell-tale rash associated with the disease, are treated for conditions such as fibromyalgia, a condition characterized by chronic joint and muscle pain. Others are told they have mental illnesses, Clark continued.
Clark said he thinks many of these people could be “false negatives” for Lyme disease -- because the current lab test checks for only one pathogenic strain of the disease, when there could be several others, he said.
“We need to think about modifying our tests,” Clark said. “I think we’re missing a lot of diagnoses.”
Lyme disease is also something people in the military are monitoring. Lt. Matthew Yans, with the Navy Entomology Center of Excellence in Jacksonville, said people serving in military operations are more aware of Lyme disease, especially during global missions, since the disease is present worldwide.
Closer to home, intense training on nature trails makes military personnel more vulnerable to tick bites, Yans said. He is is working on developing a tick pesticide as well as a tick trap.
Dr. Glenn Morris, the director of the Emerging Pathogens Institute, said the institute organized the symposium “to tackle a problem before it’s a problem,” adding that there is a lot of uncertainty among both physicians and the public about Lyme disease.
“We’re trying to stay ahead of the curve,” Morris said.
Contact Kristine Crane at 338-3119, or firstname.lastname@example.org.