April 6, 2000 (Washington) -- Just about everyone has heard of Lyme disease. But there is another illness caused by the same deer tick that may be even more serious, yet it isn't well known, even among physicians, say researchers at Yale University.
The illness is called ehrlichiosis, and it also results from a tick bite. It was first documented in humans only six years ago. Lyme disease was first reported in the 1970s. Both illnesses were common to animals before they were found to affect people.
People who have ehrlichiosis might easily mistake their symptoms for the flu, and there is no telltale rash like the one that often accompanies Lyme disease. Ehrlichiosis most commonly causes a high fever that can reach 104? or greater, intense headaches, and body aches. If untreated, the illness can cause internal bleeding and infections such as pneumonia.
A research team lead by Jacob W. IJdo, MD, found an average of about 35 yearly cases of ehrlichiosis per 100,000 residents in the 12-town area surrounding Lyme, Conn. -- 20 to 30 times higher than earlier estimates of this region. IJdo is a rheumatologist and associate research scientist at Yale University School of Medicine.
Ehrlichiosis still occurs much less frequently than Lyme disease. However, these rates of ehrlichiosis are comparable to early reports of Lyme disease.
As with Lyme disease, ehrlichiosis is thought to be more common among two age groups -- children aged 4-15 and among people in early adulthood, although this current study did not find many cases in children. It can be diagnosed with a blood test and treated with antibiotics. Of interest is that someone can actually be infected with Lyme disease and ehrlichiosis at the same time, according to M. Dana Ravyn, PhD, a microbiologist at the University of Minnesota, who was not involved in the study.
Researchers are unsure of what will happen in the future with ehrlichiosis. IJdo tells WebMD he does not know if ehrlichiosis will ever approach the current level of Lyme disease infections.
Anthony Lionetti, MD, doesn't doubt that ehrlichiosis may yet prove to be as common as Lyme disease as awareness of the condition increases among patients and doctors. He is an internal medicine specialist in Hammonton, N.J., and a consultant to the Lyme Disease Foundation in Hartford, Conn.
Ravyn says this research makes an important contribution. "These studies will help to increase understanding and awareness on part of both physicians and the public."