Lyme disease tally difficult to monitor

Rhode Island health officials say they can't tell how many new cases there are, and hope to establish an accurate reporting system.
BY PETER B. LORD
Journal Environment Writer

The state Department of Health has been having trouble tallying the incidence of Lyme disease cases here so it is about to announce a new surveillance system that it believes will generate more accurate numbers.

"We've had a lot of problems with diagnosis and treatment," said Health Department spokesman Robert Marshall. "We think there are a lot more cases."

Later, Marshall said he wasn't sure if there are more cases than now recorded by the Health Department. "We don't know. You can't compare one reporting system with another."

For years, the Health Department has been publishing very specific data on Lyme disease cases statewide, reporting a total of 2,801 cases in the last five years, ranging from a high of 852 in 2002 to a low of 249 last year.

But Marshall said the state's method of tabulating cases has been beset with problems that make the figures questionable.

Health laboratories are required to send reports of all positive Lyme disease test results to the Health Department, according to Marshall. But he said many lab reports are reconfirmations of earlier cases so the Health Department has to follow up on the reports and try to figure out which are new and which are repeats.

"We have so many being reported to us it's been overwhelming," Marshall said. "We're trying to sort it out and focus just on new cases."

In a single year, he said, the department might get 3,000 positive lab reports, but only 400 or so turn out to be new cases.

Because of delays, lags in reporting data and the time it takes to analyze the lab reports, Marshall said he has no idea whether Lyme disease this year rose along with the increased abundance of deer ticks that spread the disease.

Marshall said the new protocol will have physicians report only the new cases they diagnose. Notices are expected to go out this week. The results, he said, will allow the department to compare year to year going forward, but not backward, because the different protocol will be in use.

Underreporting of Lyme disease is a "huge issue" says Pat Smith, president of the Lyme Disease Association, a national group based in New Jersey. "That's why we have so many patients undiagnosed," Smith said.

The disease doesn't get the attention and funding it deserves, she said, because health officials routinely undercount the number of people who have it.

At the same time, she said, state programs that rely on mandatory laboratory test reporting can skew results in the other direction.

"Connecticut stopped mandatory lab reporting and the number of cases dropped by 80 percent," Smith said. (Connecticut reported 4,431 cases in 2002 and 1,403 in 2003. It attributed the decline to a change in the reporting system.)

Lyme disease in this area is caused by bacteria transmitted by deer ticks, which are much smaller than the common dog tick.

The Centers for Disease Control and Prevention reported 23,763 cases in 49 states in 2002, the worst year ever, but noted "there is considerable underreporting."

The disease poses a significant risk in just 100 counties in 12 states in the Northeast and mid-Atlantic region, the upper North-Central region and in parts of northern California.

The largest proportion of cases was reported among those age 5 to 14 and 50 to 59.

The CDC attributes the increasing number of cases to growing populations of deer, which are hosts to the disease; increased residential development in wooded areas; ticks moving into new areas, and improved recognition and reporting of the disease.

The CDC says it doesn't know the extent of the underreporting of Lyme disease, but cited studies in Connecticut and Maryland that found localities where the disease was 6 to 12 times more prevalent than what was reported.

Last November, Rhode Island Hospital opened its own Lyme clinic from 1 to 5 p.m. Tuesday afternoons. Dr. Jennifer Mitty, the clinic director, said the hospital saw an increasing need for treatment and to provide help to primary care physicians.

"We're busy," Mitty said yesterday. She said the clinic is seeing a lot more acute cases that have "management issues." It also treats chronic cases and patients with more complicated problems.

"One of the things we hope to do is to remind people to think about Lyme when they are diagnosing people," Mitty said. She said at least 20 percent of the people who get Lyme don't have the bull's-eye rash, and some who have the rash just don't see it. The remaining symptoms are much like the flu.

Dr. Nittin Damle, who practices medicine in South County and works with the Lyme disease clinic at South County Hospital, said that when he sees patients in the early stages of the disease with clear symptoms, he sees no need to order blood tests. So those cases wouldn't be counted by the Health Department under its current system.