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Lyme and the tale of two tests

Diagnosing The Disease; As ticks spread into Canada, concern rises about

rigour of existing screenings.

Lia Grainger, National Post

Published: Wednesday, August 05, 2009

_http://www.nationalpost.com/related/links/story.html?id=1860023_

(http://www.nationalpost.com/related/links/story.html?id=1860023)

When Jim Wilson was finally diagnosed with Lyme disease, he was baffled.

Now the head of the Canadian Lyme Disease Foundation, Wilson had been sick

for years and the medical community had been stumped as to the cause of his

illness. On hearing his diagnosis, his first thought was, **Why did the

doctors not even consider Lyme disease over the previous four years?**

 

 

The answer to that question lies with the guidelines used by medical

practitioners to diagnose and treat the controversial disease that is now

reported to be spreading in Canada. These guidelines are set in Canada by the

Canadian Public Health Laboratory Network (CPHLN) and in the United States by

the Infectious Disease Society of America (IDSA). Advocates for the

treatment of chronic Lyme disease believe the guidelines that dominate popular

and

expert opinion on Lyme disease in North America have caused many infected

patients to go undiagnosed and untreated. Doctors and researchers who set

the guidelines disagree and believe changes to the guidelines could lead to

misdiagnoses and to the misuse of antibiotics on patients who do not have

Lyme disease.

 

 

Both the U. S. and Canadian guidelines advocate a two-tiered testing

system that requires a positive screening test, called an ELISA or EIA test,

before proceeding to a Western blot test. Lyme disease advocates such as Dr.

Ernie Murakami of British Columbia believe it is this system that is leading

to thousands of missed diagnoses a year. " It should be based on a clinical

diagnosis, " Murakami says. " These tests are notorious for turning out

false negative results. "

 

 

Dr. Muhammad Morshed is a clinical microbiologist at the University of

British Columbia. He contributed to both guidelines, and sees no need for a

revision. " From a laboratory point of view, I don't think we need to alter

anything, " Morshed says. " We can always adjust it if we find out more

information, but the two-tiered system --a screening with a sensitive test

followed by a very specific complementary test -- stands in a good way from a

laboratory point of view. "

 

 

Most Lyme disease advocates believe that the Western blot test produces

more accurate results, and many Canadian patients who believe they may have

Lyme disease pay private laboratories in the U. S. to give them this test.

Dr. Nicholas Ogden is an expert in tick-borne diseases at the Universite de

Montreal in Quebec and a researcher at the Public Health Agency of Canada,

and he encourages patients to be cautious when sending blood to be tested

by commercial laboratories in the U. S. He says for-profit laboratories may

be using unproven interpretations of tests that are themselves recognized,

like the Western blot test. " It's an issue that does potentially muddy the

waters, " Ogden says. " They may be using very loose interpretations of test

results. "

 

 

Both guidelines also advise testing only if the patient has been exposed

to a known endemic area during tick season, but a recent study headed by

Ogden and co-authored by Morshed reveals that the endemic areas in Canada are

more widespread than previously believed, and will continue to grow as

global warming creates an environment increasingly hospitable to ticks. Once

believed to be contained to a small area of Lake Erie's shoreline in Ontario,

the report says that Lyme disease has now been identified in southern

Ontario, Nova Scotia, southeastern Manitoba, New Brunswick and southern British

Columbia. The report also warns of a low risk of contracting the disease

outside of endemic areas from ticks that have fallen off migratory birds.

 

 

Perhaps most concerning to advocates on both sides of the border, though,

has been the virtual dismissal in the U. S. guidelines of the very

existence of chronic Lyme disease. The U. S. guidelines currently state:

 

 

**Unfortunately, it is apparent that the term *chronic Lyme disease* is

also being applied to patients with vague, undiagnosed complaints who have

never had Lyme disease ... the majority of patients [who believe they have

chronic Lyme disease] have had no convincing evidence of ever having had Lyme

disease, on the basis of the absence of objective clinical, microbiologic

or serologic evidence of past or present.**

 

 

Since their publication, these findings have been called into question. In

May 2008, Richard Blumenthal, the Attorney General of Connecticut, began

an investigation of the IDSA*s 2006 guidelines, based on allegations that

**the IDSA's guideline panel improperly ignored or minimized consideration of

alternative medical opinion and evidence regarding chronic Lyme disease,

potentially raising serious questions about whether the recommendations

reflected all relevant science.**

 

 

Blumenthal also reported that members of the IDSA panel **undercut its

credibility by allowing individuals with financial interests --in drug

companies, Lyme disease diagnostic tests, patents and consulting arrangements

with

insurance companies -- to exclude divergent medical evidence and

opinion.**

 

 

The IDSA denied all of Blumenthal's findings and negotiated an end to the

investigation by agreeing to form an entirely new panel monitored by the

office of the Attorney General to review the guidelines. That review

commenced with a hearing last Thursday, and the panel says it hopes to publish

its

findings by the end of this year.

 

 

Though Canada operates under its own guidelines, they are similar to those

set by the IDSA that are currently under review. The continued discord

over the very existence of chronic Lyme disease in the U. S. coupled with the

reported spread to new previously unaffected areas of Canada seems likely

to increase the visibility of the issue on both sides of the border in the

coming months.

 

 

For the time being, there have been no announcements of plans to alter the

Canadian guidelines, though both Morshed and Ogden say new findings could

lead to changes. " We're not sitting idly by and saying these are the best

tests and we're not doing anything about it, " Ogden says. " We know they're

not perfect. "

 

 

- For updates on ticks and what to do if you're bit, visit Health Canada

at hc-sc. gc.ca.

 

_lgrainger_ (lgrainger)

 

 

 

Previous article:

 

(http://www.nationalpost.com/life/health/story.html?id=1862262) Debate

over Lyme disease lingers on, with a U.S. twist

Lia Grainger, National Post Published: Wednesday, August 05, 2009

_http://www.nationalpost.com/life/health/story.html?id=1862262_

(http://www.nationalpost.com/life/health/story.html?id=1862262)

 

 

 

 

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