Numbers on diseases called misleading

By Timothy Pratt

Friday, Nov. 29, 2002 | 10:52 a.m.

An increase in cases of certain diseases reported on the Clark County Health District's website for October does not mean there are epidemics, and officials cautioned against knee-jerk responses to the data.

Instead, they said, the numbers may be a sign that post-Sept. 11 efforts to encourage doctors, nurses and labs to report diseases to the government may be paying off.

That, together with factors such as new, improved testing methods and people moving from out of state, has driven up the numbers of reported cases of certain diseases this year.

"There has been a lot of information given to the medical community about the importance of reporting to us, coming from a lot of directions," said Rose Lee Bell, epidemiology manager for the district.

But higher numbers on the county's website may be misleading, and a look at the data has raised questions about how best to inform the public, or whether the numbers should be posted at all.

Efforts during the last year to strengthen ties between the medical community and government include federally funded seminars, state plans on bioterrorism and a local training program for 2,000 doctors and nurses on unusual diseases. A total of $10.5 million in federal funds was given to Nevada for building up the health care infrastructure as a line of defense against bioterrorism, said Randall Todd, state epidemiologist with the Nevada State Health Division.

"I think with the concern for bioterrorism, there is a greater understanding ... about why we've been asking them to report diseases all these years," said Mary Ellen Harrell, public health nurse manager for the district.

"After Sept. 11 ... there has been more testing and more reporting (of diseases)."

The result: The numbers for diseases such as chlamydia, a sexually transmitted disease, AIDS, whooping cough, and a lower respiratory virus called RSV have all risen as of October when compared to the year to date in 2001.

With chlamydia, reported cases have gone from 3,379 to 3,785 -- an increase of of 12 percent. Part of the jump can be attributed to easier and quicker tests being made available in the last year, Harrell said. That along with increased reporting helps explain the greater numbers of cases reported to the district.

But the new numbers don't necessarily mean there is an outbreak in chlamydia, Harrell said.

"It was difficult before to tell what the true incidence of the disease in the community was ... (so) in some cases, it's not an indicator of there being more of a disease in the community," she said.

With AIDS, the number of reported cases has gone from 146 to 221 -- an increase of about 50 percent.

Mary Resnick, a member of the district's HIV/AIDS surveillance program, said that part of the increase may be due to an influx of new residents from out of state who come to Nevada to take advantage of federal funding available for AIDS patients.

And, she said, doctors seem to be cooperating more with the district in helping them trace patient histories.

"We're not getting as much resistance as we did in the past when we go to them to ask for patient charts," she said. "Hopefully, they're realizing the importance of reporting to us."

Whooping cough showed a sharp rise from four to 22 cases, but this was in line with a national trend, Harrell said.

"Through the Centers for Disease Control, we already knew this was happening elsewhere," she said. The district responded by mounting a child immunization program that seems to have helped drive the numbers back down in recent months.

And RSV cases went from 1,342 to 1,902 in the last year -- an increase of 29 percent.

But this virus tends to run in cycles, so some years are higher than others, Harrell said. "And we have no idea why," she added.

Also, the figures in the year to date up to October mostly reflect higher numbers in the winter months of January and February, and there is no way of knowing if the upcoming winter will yield similar results.

Officials agreed that increased reporting is good, but that the website may be misinterpreted by the untrained eye.

"Though something's on the web and it's accessible, it may not be intended just for the layperson, and is also for use by health care professionals," Todd said.

"We sort of are under a two-edged sword. On the one hand, you have an audience the needs to have the data as fast as possible. But on the other hand, if you make the data more presentable for the layperson, it takes more time."

District officials said that changes to the county website may make it easier to please both audiences.

"I think if we know we have problem with a particular disease, then we should put something in there," Harrell said. She also said that the Las Vegas Valley's fast-growing population could play a part in any increase shown in a disease reported.

Resnick said that footnotes for each disease could explain the factors behind rises or falls in cases reported from month to month and year to year.

But Bell, the epidemiology manager, said it would be difficult to explain every disease.

"Maybe it would be better to not post the numbers at all," she said.