Lyme DiseaseBy, Cheryl Poleschuk and Linda Hansen

What is Lyme Disease?

An acute inflammatory disease characterized by a rash with joint swelling and fever

Caused by the bacterium Borrelia Burgdorferi, which is carried by the tick Ixodes Scapularis

Named after the town Old Lyme, Connecticut where an epidemic of arthritis occurred in the ‘70s

Leading arthropod-born disease in the US

Zoonotic Infection

Ixodes ScapularisKingdom: AnimaliaPhylum: ArthropodaClass: ArchanidaOrder: IxodidaFamily: IxodidaeGenus:IxodesSpecies: Scapularis

Ixodes Scapularis Vector for Lyme disease

Common name: black-legged tick or deer tick

Found in Eastern and North-Central US

Feeds on wide variety of hosts including humans

Have 3 hosts in their lifetime- one for each life stage

Transmits other diseases Babesiosis Anaplasmosis

Between 25-50% of deer ticks are infected with B. Burgdorferi in North eastern US

MorphologyHard-bodied ticksAdult and nymph stages have 8 legsLarva has 6 legsAnal groove is anterior to the anusFlattened dorsoventrally in the unfed stateCuticle grows to accommodate the blood mealMarked sexual dimorphism in size and often

in colorFemales are larger and have larger mouth parts

than males

Life Cyclehttp://cal.vet.upenn.edu/projects/parasit06/lif

e%20cycles/tick_site/animlife.htm

SymptomsFirst sign of infection is a circular rash called

erythema migrans70-80% get the rashGradually expandsBull’s eye like appearanceFlu-like symptoms = fatigue, chills, fever,

headachesMigratory joint painSwollen lymph nodes

Symptoms cont.If left untreated infection can spread to other

parts of the body within a few days to weeksLoss of muscle tone on one or both sides of the

face = Bell’s PalsySevere headaches and neck stiffness due to

meningitisShooting painsHeart palpitations and dizzinessJoint pain

Symptoms cont.After several months…

About 60% with untreated infection begin to have intermittent bouts of arthritis with severe joint pain and swelling; especially in the knees

5% may develop chronic neurological complaints Shooting pains, numbness or tingling in hands

and/or feet Problems with concentration and short term

memory

Symptoms cont.A small percentage of treated people

continue to have symptoms that last for months after treatmentMuscle and joint pain, arthritis, cognitive

defects, sleep disturbances, or fatigueCause unknownSome evidence states that these symptoms

result from the autoimmune response The immune system continues to respond after

infection has been cleared

DiagnosisCharacteristic rashHistoryLab tests

ELISAIf ELISA is positive, Western blot is used to

confirm the diagnosis

TreatmentAntibiotics

Doxycycline for adultsAmoxicillin or Cefuroxime axetil for children or

pregnant mothers

ControlAvoid woody, bushy areas with lots of grassUse 20-30% DEET insect repellent and/or

Permithin Tick Check!Cover your skin

ReferencesCDC.gov/lymediseaseRoberts, Larry S. "Foundations of

Parasitology." New York: The McGraw-Hill Company, 2009.

Mayoclinic.com/lymediseasehttp://cal.vet.upenn.edu/projects/parasit06/lif

e%20cycles/tick_site/animlife.htm