LYME DISEASE

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LYME DISEASE

• Other names Erythema (chronicum) migrans, Lyme
  borreliosis
  
• Agent Borrelia burgdorferi, a bacterial
  infection (spirochete)
  
• a tick-borne zoonosis affecting animals and man

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LYME DISEASE

• Microbiological features
• spirochete family, related to Treponema and
  Leptospira
  
• fastidious
• slow growing
• periplasmic flagella associated with both shape
  of organism and movement
  
• entire genome has been sequenced

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LYME DISEASE

• Microbiological features
• surface proteins important in detection and
  vaccine development
  
• OspA produced by spirochetes when in midgut of
  tick
  
• OspC produced upon bloodmeal (environmental
  triggers in blood and temperature?)
  
• both may be needed for effective vaccination

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LYME DISEASE
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LYME DISEASE
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LYME DISEASE

• First recognized in Lyme, CT in 1975 as an
  unusual occurrence of juvenile rheumatoid
  arthritis
  
• Continues to be a rapidly emerging infectious
  disease
  
• Accounts for more than 90 of all reported
  vector-borne illnesses reported in the US

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LYME DISEASE

• Epidemiology
• occurrence
• normally seen in the summer, peak in June and
  July
  
• in the US, endemic foci along the Atlantic coast
  (MA to ME), upper Midwest (WI, MN), West coast
  (CA, OR)
  
• also found in Canada, Europe, Russia, Japan,
  China
  

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LYME DISEASE

• Epidemiology
• reservoir
• wild rodents (Peromyscus spp.)
• deer
• certain ixodid ticks through transstadial
  transmission

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LYME DISEASE

• Epidemiology
• mode of transmission
• bite of tick
• in experimental animals, transmission does not
  occur until tick has been attached for at least
  24 hours may be similar for humans

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LYME DISEASE

• Epidemiology
• vector
• Ixodes scapularis (I. dammini) - East and Midwest
  US
  
• I. pacificus - West coast
• I. ricinus - Europe
• I. persulcatus - Asia

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LYME DISEASE

• Clinical features
• humans
• early manifestations
• fatigue, fever, myalgia, headache,
  lymphadenopathy, migratory arthralgia
  
• distinctive skin lesion (EM) at site of bite
  (60 of cases)

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LYME DISEASE

• Clinical features
• later manifestations
• neurological - meningitis, cranial neuritis
  including facial (Bells) palsy, ataxia,
  myelitis, radiculoneuritis, encephalitis
  
• cardiac - atrioventricular block, cardiomegaly
• articular - intermittent episodes of swelling and
  pain in large joints, especially knee
  
• both neurologic and arthritic symptoms may recur
  following long periods of latency

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LYME DISEASE

• Erythema migrans (EM)

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LYME DISEASE

• Erythema migrans (EM)

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LYME DISEASE

• Erythema migrans (EM)

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LYME DISEASE

• Risk of disease by region

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LYME DISEASE

• Clinical features
• animals
• dogs, cattle, and horses may develop systemic
  disease, with articular and cardiac
  mainfestations similar to that seen in humans

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LYME DISEASE

• Diagnosis
• currently based on clinical signs supported by
  serology
  
• confirmation of some cases remains problematic
• commonly used serologic tests lack precision and
  accuracy
  
• cross-reactivity with syphilis, relapsing fever,
  leptopsirosis, HIV, RMSF, infectious
  mononucleosis, SLE, RA

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LYME DISEASE

• Diagnosis
• a standardized two-test approach to serologic
  testing for antibodies to B. burgdorferi
  
• ELISA - outer surface protein Ag more sensitive
• Western blot
• IgM ELISA for early detection of Ab
• PCR, LUAT for early detection of Ag in urine
• growth on BSK from biopsy (50 of cases) to
  differentiate from other Lyme-like diseases

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LYME DISEASE

• Exposure
• peridomestic, residential
• recreational
• occupational

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LYME DISEASE

• Prevention
• avoid tick-infested habitats
• personal protection
• periodic total body search for presence of ticks
• early removal of tick since transmission
  inefficient prior to at least 24 hours
  attachment
  
• immunization - vaccines specifically for OspA and
  OspC hold promise

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LYME DISEASE

• Control
• interruption of peridomestic cycle
• tick control
• active surveillance of ticks and wildlife
• to monitor changes in the distribution
• to provide early detection
• to determine risk indices
• to provide prevalence data to evaluate
  effectiveness of prevention programs