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