LYME DISEASE • Other names: Erythema (chronicum) migrans, Lyme borreliosis • Agent: Borrelia burgdorferi, a bacterial infection (spirochete) • a tick-borne zoonosis affecting animals and man
May 15, 2015
LYME DISEASE
• Other names: Erythema (chronicum) migrans, Lyme borreliosis
• Agent: Borrelia burgdorferi, a bacterial infection (spirochete)
• a tick-borne zoonosis affecting animals and man
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
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
LYME DISEASE
LYME DISEASE
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
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
LYME DISEASE
• Epidemiology:
– reservoir• wild rodents (Peromyscus spp.)• deer• certain ixodid ticks through transstadial
transmission
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
LYME DISEASE
• Epidemiology:
– vector• Ixodes scapularis (I. dammini) - East and
Midwest US• I. pacificus - West coast• I. ricinus - Europe• I. persulcatus - Asia
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)
LYME DISEASE
• Clinical features:– later manifestations:• neurological - meningitis, cranial neuritis
including facial (Bell’s) 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
LYME DISEASE
• Erythema migrans (EM)
LYME DISEASE
• Erythema migrans (EM)
LYME DISEASE
• Erythema migrans (EM)
LYME DISEASE
• Risk of disease by region
LYME DISEASE
• Clinical features:– animals:• dogs, cattle, and horses may develop
systemic disease, with articular and cardiac mainfestations similar to that seen in humans
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
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
LYME DISEASE
• Exposure:
– peridomestic, residential– recreational– occupational
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
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