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Lyme Disease and Southern Tick Associated Rash Illness (STARI) in Texas: What we know; what we need to know

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Lyme Disease and Southern Tick Associated Rash Illness (STARI) in Texas: What we know; what we need to know. Stephen Waring, DVM, PhD Associate Professor Epidemiology, Biological Sciences. Lyme Disease Ecology. Lyme Disease: Epidemiology. Number of cases – US: 1993 - 2007.

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Lyme Disease and Southern Tick Associated Rash Illness (STARI) in Texas:What we know; what we need to know

Stephen Waring, DVM, PhD

Associate Professor

Epidemiology, Biological Sciences

lyme disease epidemiology
Lyme Disease:Epidemiology
  • Number of cases – US: 1993 - 2007
lyme disease epidemiology4
Lyme Disease:Epidemiology
  • Number of cases – Texas: 1993 - 2007
lyme disease epidemiology5
Lyme Disease:Epidemiology
  • Incidence in US: 2007

* Among states reporting at least one case

Source: CDC

lyme disease clinical
Lyme Disease:Clinical

Early localized (1 - 4 weeks)

  • Flu-like (with or without rash)
    • fatigue
    • chills
    • fever
    • headache
    • muscle/joint aches
    • swollen lymph nodes
  • Erythemamigrans (70-80%)
    • site of tick bite 3 – 30 day delay in appearance

Source: CDC; WebMD

lyme disease clinical7
Lyme Disease:Clinical

Early disseminated (1 - 4 months)

  • facial nerve paralysis (Bell’s palsy)
  • meningitis (headaches, neck stiffness, dizziness)
  • cognitive deficits (memory, concentration)
  • migrating pain
  • heart palpatations

Source: CDC; WebMD

lyme disease clinical8
Lyme Disease:Clinical

Late persistent infection (> 4 months)

Feder et al NEJM 2007

slide10

Lyme Disease:Clinical

  • Results of clinical trials on Category 4 patients:
    • Substantial risk with little or no benefit of continued antibiotics after appropriate initial treatment of Lyme disease

Feder et al NEJM, 2007

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Chronic debate over chronic Lyme Disease

(Post-Lyme disease syndrome)

Source: Nature Medicine 2008

post lyme disease syndrome confounding factors with subjective symptoms
Post Lyme Disease Syndrome:Confounding factors with subjective symptoms
  • Patients told they have Lyme but do not
    • >50% in one study at major tertiary care center had symptoms more likely explained by fibromyalgia and chronic fatigue syndrome
    • Lack of laboratory evidence
    • Improper advise based on testing that lacks validation (high rates of false positives) (warning in MMWR, 2005)
  • High prevalence of subjective symptoms in general population creates considerable ‘noise’ - can be even higher than that reported for Lyme disease
    • Hence long standing directives not to perform diagnostic tests for Lyme for subjects with only subjective symptoms

Source: Auwaerter CID 2007

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Post Lyme Disease Syndrome:Long-term antibiotic therapy

  • Highly vocal debate fueled by frustrations stemming from:
    • unmet needs of patients
    • incomplete understanding of post-Lyme syndrome

Bottom line: more research needed

Source: Point (A/CounterpointCID 2007

lyme disease recent findings
Lyme Disease: Recent findings
  • Genotyping
    • 4 genotypes in outer surface protein C gene (OspC) account for >80% of cases with EM from NY (Wormser et al, JID 2008)
  • Climate
    • climate-associated variability in the timing of I. scapularishost seeking contributesto geographic heterogeneities in frequencies of B. burgdorferi genotypes (Gatewood et al, App Environ Microbiol 2009)
  • Virulence factor
    • bacterial protein (BmtA) associated with transporting manganese across membrane important in growth of organism (Ouyang et al PNAS 2009)
lyme like disease stari ecology
Lyme-like Disease (STARI)Ecology

Distribution of Amblyomma americanum, 2006 (courtesy of M. Yabsley, U Georgia)

Transmission earlier in year than Lyme disease due to feeding habits of adults/nymphs

Vector: Amblyomma americanum (Lone State tick)

All stages are aggressive feeders and bite humans

lyme like disease stari clinical
Lyme-like Disease (STARI)Clinical

Compared to Lyme disease:

  • Milder flu-like symptoms
    • regional lymphadenopathy less likely
    • patients less symptomatic at time of rash
  • Erythemamigrans (100%)
    • site of tick bite
    • patients more likely to report tick bite
  • More rapid recovery from treatment

Masters et al Inf Dis Clin NA 2008

lyme like disease stari diagnosis
Lyme-like Disease (STARI)Diagnosis
  • Causative organism undetermined
    • Borrelia lonestari isolated from dermatological biopsy of one case but later series have failed to isolate organism
    • Therefore, no serological test available at present
  • Clinical diagnosis based on presence of rash

Masters et al Inf Dis Clin NA 2008

lyme and lyme like disease what next20
Lyme and Lyme-like DiseaseWhat next?
  • Transmission studies
    • role of outer surface proteins (OspA & Osp B) -essential for colonization and survival of Bb in ticks
    • role of gene BptA (Borreliapersistence in ticks-Gene A) - major role in virulence and survival of organism in vector
    • Role of global warming favoring emergence of more persistent/virulent strains in endemic regions with lower incidence (Upper Midwest) and in non-endemic regions
lyme and lyme like disease what next for texas
Lyme and Lyme-like DiseaseWhat next for Texas?
  • Burning question: why such a low prevalence of tick-borne zoonoses (human cases) with so many ticks, so many people, and such a high risk for exposure?
    • Systematic surveillance (ticks and reservoir hosts)
    • Comparative studies of phenology (ecologic and climatic influences on ticks and persistence/virulence of pathogens
    • What is the etiologic agent for STARI and is it just one mutation away from producing a much more serious Lyme-like illness?
    • Does tick behavior in defined ecologic niches favor a vector that is just less efficient in transmitting virulent human disease?
    • The role of co-infection with animal and human pathogens in modifying infectivity/virulence (ex: could B. lonestari be a primary animal pathogen that just ‘outcompetes’ B. burgdorferi?

Stay tuned…

lyme and lyme like disease what next22
Lyme and Lyme-like DiseaseWhat next?
  • Genomics/phylogenetics
    • Ex: study ‘in press’ indicates B. burgdorferi isolates from northern US not genetically distinct from isolates in the southern US (M. Yabsley, personal communication)
  • Role of pathogen-host relationships in tick-borne zoonoses
    • Ex: borreliacidal saliva in Ambloymma in modifying virulence
  • Ecological characteristics
    • Ex: geospatial analytic methods to study factors in emergence and to inform transmission cycles (sylvatic, peridomestic, domestic)
lyme disease and lyme like disease in texas what we know what we need to know
Lyme Disease and Lyme-like Disease in Texas:What we know; what we need to know

The art of medicine consists of amusing the patient while nature cures the disease.

Voltaire