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What makes Lyme disease such a medical challenge? Holly Ahern MS, MT(ASCP) Associate Professor of Microbiology SUNY Adirondack, Queensbury, NY

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Presentation on theme: "What makes Lyme disease such a medical challenge? Holly Ahern MS, MT(ASCP) Associate Professor of Microbiology SUNY Adirondack, Queensbury, NY"— Presentation transcript:

1 What makes Lyme disease such a medical challenge? Holly Ahern MS, MT(ASCP) Associate Professor of Microbiology SUNY Adirondack, Queensbury, NY ahernh@sunyacc.edu

2 Lyme Disease – A Tick-borne Spirochetosis?  Lyme disease in humans was first described in 1977 as an “epidemic of arthritis” preceded by a rash.  Dr. Wilhelm Burgdorfer dissected ticks from Shelter Island NY and found them to be full of microbes.  Burgdorfer showed that one of them, a spirochete in the genus Borrelia, caused the same type of disease when rabbits were infected.  The spirochete was named Borrelia burgdorferi, and this sole bacterium is STILL considered the one and only cause of “Lyme disease” in the United States.

3 Borrelia are not like other bacteria… Other Bacteria  May survive outside a host  Reproduce rapidly and grow to large numbers  Have an arsenal of sophisticated weaponry  Engage the host immune system  Induce strong and long- lasting immunity. Borrelia  Can’t survive without a host  Reproduce slowly and sometimes don’t reproduce at all.  Lack classic bacterial weaponry like toxins or enzymes.  Evade or subvert the host immune system  Seldom induce strong or long lasting immunity

4 Lyme disease is not like other diseases caused by bacteria Other Bacterial Diseases  Disease is apparent with a defined beginning and end  Clear and characteristic “signs” and “symptoms”  Accurate diagnostic tests are available  Antibiotics are a very effective treatment because the bacteria are reproducing Lyme disease  Disease may not always be apparent and timeline varies  Multi-system disease that isn’t always the same  Diagnostic test endorsed by the CDC is only 50% accurate  Antibiotics are not always effective because Borrelia are antibiotic tolerant bacteria

5 Relationships between Borrelia and hosts are complicated They have a “life cycle” that involves animals and ticks.  Exceptional, well adapted animal commensals that cause persistent BUT NOT DISEASE INDUCING infection in their “reservoir” host (mice in our area).  Partner with blood sucking insects (ticks) to get transmitted to new host animals (including us).  Long-lived animals (like us) with strong adaptive immunity experience symptoms of disease but no sterilizing immunity  Disease symptoms are due largely to infection- associated inflammation

6 Borrelia live a complicated life  Genome is more complex than any other bacteria  One chromosome, multiple plasmids.  Vary gene expression depending on environment  Exchange genes with other Borrelia  Genetic variation leads to ongoing evolution of new genospecies of Borrelia – which ones actually “cause” Lyme disease?  Cells change over time (“pleomorphic”) A.Spirochete (twisted rod) is motile and swims B.Non-motile forms produce a “BIOFILM” C.Twisted form balls up into a rounded form which stop eating and reproducing, become antibiotic tolerant “persisters” A B C

7 Our immune system responds to the same Borrelia in different ways Borrelia spirochetes Spirochetes forming “round bodies” Round body “persisters” Biofilm of Borrelia

8 Why blood tests for Lyme disease don’t work  Current “gold standard” blood tests detect immune system response to infection, NOT the infection itself.  Bacteria shut down antibody production by disrupting “germinal centers” in lymph nodes.  Borrelia changes its surface antigens to trick the immune system.  Other Borrelia species cause Lyme disease or “Lyme-like” disease. Blood tests are specific for ONLY the SPIROCHETE FORM of B. burgdorferi Accuracy of this test is <50%

9 Why a standard antibiotic treatment approach doesn’t always work  Antibiotic dose required to kill bacteria in biofilm for is 1,000 – 5,000 times higher than for motile forms.  Pleomorphic forms (called cysts or round bodies or persisters) are antibiotic tolerant  They slow their rate of growth  They become dormant “persisters” with no reproduction  Remove antibiotic challenge, growth rate speeds up and/or persisters reactivate causing recurrence of symptoms

10 So, what does work? Thanks to funding from non-profit organizations, research to identify antimicrobial agents effective against Borrelia spirochetes and persisters is finally underway Congress – NIH and CDC are federal agencies funded by tax dollars. Why isn’t more being done???

11 What we NEED:  An accurate diagnostic test for all known tick-borne diseases  Better rate of accuracy (>50%)  Detects actual presence of bacteria  Based on genomic analysis – detects DNA or RNA from more than just Borrelia burgdorferi  Better treatment approaches, for tick bite AND BEYOND  Identify new antimicrobial drugs that work against Borrelia persisters  Identify new approaches that work against bacterial biofilms  Investigate how Borrelia infection evades and disables the immune system  STOP MARGINALIZING PATIENTS WHO DON’T RECOVER AFTER 2 WEEKS OF ANTIBIOTICS  Ways to prevent tick bites in the first place!  Oral vaccine in pellets for mice  Chemical and biological treatments; environment and personal protection  LEADERSHIP from US and State reps  Public Health Policies for Lyme disease MUST BE CHANGED!


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