LYME DISEASE Other names: Erythema (chronicum) migrans, Lyme ...


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LYME DISEASE Other names: Erythema (chronicum) migrans, Lyme ...

  1. 1. LYME DISEASE <ul><li>Other names: Erythema (chronicum) migrans, Lyme borreliosis </li></ul><ul><li>Agent: Borrelia burgdorferi, a bacterial infection (spirochete) </li></ul><ul><li>a tick-borne zoonosis affecting animals and man </li></ul>
  2. 2. LYME DISEASE <ul><li>Microbiological features </li></ul><ul><ul><li>spirochete family, related to Treponema and Leptospira </li></ul></ul><ul><ul><li>fastidious </li></ul></ul><ul><ul><li>slow growing </li></ul></ul><ul><ul><li>periplasmic flagella associated with both shape of organism and movement </li></ul></ul><ul><ul><li>entire genome has been sequenced </li></ul></ul>
  3. 3. LYME DISEASE <ul><li>Microbiological features </li></ul><ul><ul><li>surface proteins important in detection and vaccine development </li></ul></ul><ul><ul><ul><li>OspA produced by spirochetes when in midgut of tick </li></ul></ul></ul><ul><ul><ul><li>OspC produced upon bloodmeal (environmental triggers in blood and temperature?) </li></ul></ul></ul><ul><ul><ul><li>both may be needed for effective vaccination </li></ul></ul></ul>
  6. 6. LYME DISEASE <ul><li>First recognized in Lyme, CT in 1975 as an unusual occurrence of juvenile rheumatoid arthritis </li></ul><ul><li>Continues to be a rapidly emerging infectious disease </li></ul><ul><li>Accounts for more than 90% of all reported vector-borne illnesses reported in the US </li></ul>
  7. 7. LYME DISEASE <ul><li>Epidemiology: </li></ul><ul><ul><li>occurrence: </li></ul></ul><ul><ul><ul><li>normally seen in the summer, peak in June and July </li></ul></ul></ul><ul><ul><ul><li>in the US, endemic foci along the Atlantic coast (MA to ME), upper Midwest (WI, MN), West coast (CA, OR) </li></ul></ul></ul><ul><ul><ul><li>also found in Canada, Europe, Russia, Japan, China </li></ul></ul></ul>
  8. 8. LYME DISEASE <ul><li>Epidemiology: </li></ul><ul><ul><li>reservoir </li></ul></ul><ul><ul><ul><li>wild rodents ( Peromyscus spp.) </li></ul></ul></ul><ul><ul><ul><li>deer </li></ul></ul></ul><ul><ul><ul><li>certain ixodid ticks through transstadial transmission </li></ul></ul></ul>
  9. 9. LYME DISEASE <ul><li>Epidemiology: </li></ul><ul><ul><li>mode of transmission: </li></ul></ul><ul><ul><ul><li>bite of tick </li></ul></ul></ul><ul><ul><ul><li>in experimental animals, transmission does not occur until tick has been attached for at least 24 hours; may be similar for humans </li></ul></ul></ul>
  10. 10. LYME DISEASE <ul><li>Epidemiology: </li></ul><ul><ul><li>vector </li></ul></ul><ul><ul><ul><li>Ixodes scapularis (I. dammini) - East and Midwest US </li></ul></ul></ul><ul><ul><ul><li>I. pacificus - West coast </li></ul></ul></ul><ul><ul><ul><li>I. ricinus - Europe </li></ul></ul></ul><ul><ul><ul><li>I. persulcatus - Asia </li></ul></ul></ul>
  11. 11. LYME DISEASE <ul><li>Clinical features: </li></ul><ul><ul><li>humans: </li></ul></ul><ul><ul><ul><li>early manifestations: </li></ul></ul></ul><ul><ul><ul><ul><li>fatigue, fever, myalgia, headache, lymphadenopathy, migratory arthralgia </li></ul></ul></ul></ul><ul><ul><ul><ul><li>distinctive skin lesion (EM) at site of bite (~60% of cases) </li></ul></ul></ul></ul>
  12. 12. LYME DISEASE <ul><li>Clinical features: </li></ul><ul><ul><li>later manifestations: </li></ul></ul><ul><ul><ul><li>neurological - meningitis, cranial neuritis including facial (Bell’s) palsy, ataxia, myelitis, radiculoneuritis, encephalitis </li></ul></ul></ul><ul><ul><ul><li>cardiac - atrioventricular block, cardiomegaly </li></ul></ul></ul><ul><ul><ul><li>articular - intermittent episodes of swelling and pain in large joints, especially knee </li></ul></ul></ul><ul><ul><ul><li>both neurologic and arthritic symptoms may recur following long periods of latency </li></ul></ul></ul>
  13. 13. LYME DISEASE <ul><li>Erythema migrans (EM) </li></ul>
  14. 14. LYME DISEASE <ul><li>Erythema migrans (EM) </li></ul>
  15. 15. LYME DISEASE <ul><li>Erythema migrans (EM) </li></ul>
  16. 16. LYME DISEASE <ul><li>Risk of disease by region </li></ul>
  17. 17. LYME DISEASE <ul><li>Clinical features: </li></ul><ul><ul><li>animals: </li></ul></ul><ul><ul><ul><li>dogs, cattle, and horses may develop systemic disease, with articular and cardiac mainfestations similar to that seen in humans </li></ul></ul></ul>
  18. 18. LYME DISEASE <ul><li>Diagnosis </li></ul><ul><ul><li>currently based on clinical signs supported by serology </li></ul></ul><ul><ul><li>confirmation of some cases remains problematic </li></ul></ul><ul><ul><li>commonly used serologic tests lack precision and accuracy </li></ul></ul><ul><ul><li>cross-reactivity with syphilis, relapsing fever, leptopsirosis, HIV, RMSF, infectious mononucleosis, SLE, RA </li></ul></ul>
  19. 19. LYME DISEASE <ul><li>Diagnosis </li></ul><ul><ul><li>a standardized two-test approach to serologic testing for antibodies to B. burgdorferi </li></ul></ul><ul><ul><ul><li>ELISA - outer surface protein Ag more sensitive </li></ul></ul></ul><ul><ul><ul><li>Western blot </li></ul></ul></ul><ul><ul><li>IgM ELISA for early detection of Ab </li></ul></ul><ul><ul><li>PCR, LUAT for early detection of Ag in urine </li></ul></ul><ul><ul><li>growth on BSK from biopsy (50% of cases) to differentiate from other Lyme-like diseases </li></ul></ul>
  20. 20. LYME DISEASE <ul><li>Exposure: </li></ul><ul><ul><li>peridomestic, residential </li></ul></ul><ul><ul><li>recreational </li></ul></ul><ul><ul><li>occupational </li></ul></ul>
  21. 21. LYME DISEASE <ul><li>Prevention: </li></ul><ul><ul><li>avoid tick-infested habitats </li></ul></ul><ul><ul><li>personal protection </li></ul></ul><ul><ul><li>periodic total body search for presence of ticks </li></ul></ul><ul><ul><li>early removal of tick since transmission inefficient prior to at least 24 hours attachment </li></ul></ul><ul><ul><li>immunization - vaccines specifically for OspA and OspC hold promise </li></ul></ul>
  22. 22. LYME DISEASE <ul><li>Control: </li></ul><ul><ul><li>interruption of peridomestic cycle </li></ul></ul><ul><ul><li>tick control </li></ul></ul><ul><ul><li>active surveillance of ticks and wildlife </li></ul></ul><ul><ul><ul><li>to monitor changes in the distribution </li></ul></ul></ul><ul><ul><ul><li>to provide early detection </li></ul></ul></ul><ul><ul><ul><li>to determine risk indices </li></ul></ul></ul><ul><ul><ul><li>to provide prevalence data to evaluate effectiveness of prevention programs </li></ul></ul></ul>