Transcript Lyme Disease - Winona State University

By, 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 Scapularis
 Kingdom: Animalia
 Phylum: Arthropoda
 Class: Archanida
 Order: Ixodida
 Family: Ixodidae
 Genus:Ixodes
 Species: 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
Morphology
 Hard-bodied ticks
 Adult and nymph stages have 8 legs
 Larva has 6 legs
 Anal groove is anterior to the anus
 Flattened dorsoventrally in the unfed state
 Cuticle grows to accommodate the blood meal
 Marked sexual dimorphism in size and often in color
 Females are larger and have larger mouth parts than
males
Life Cycle
 http://cal.vet.upenn.edu/projects/parasit06/life%20cy
cles/tick_site/animlife.htm
Symptoms
 First sign of infection is a circular rash called erythema
migrans
 70-80% get the rash
 Gradually expands
 Bull’s eye like appearance
 Flu-like symptoms = fatigue, chills, fever, headaches
 Migratory joint pain
 Swollen lymph nodes
Symptoms cont.
 If left untreated infection can spread to other parts of
the body within a few days to weeks
 Loss of muscle tone on one or both sides of the face =




Bell’s Palsy
Severe headaches and neck stiffness due to meningitis
Shooting pains
Heart palpitations and dizziness
Joint 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 treatment
 Muscle and joint pain, arthritis, cognitive defects, sleep
disturbances, or fatigue
 Cause unknown
 Some evidence states that these symptoms result from
the autoimmune response

The immune system continues to respond after infection has
been cleared
Diagnosis
 Characteristic rash
 History
 Lab tests
 ELISA
 If ELISA is positive, Western blot is used to confirm the
diagnosis
Treatment
 Antibiotics
 Doxycycline for adults
 Amoxicillin or Cefuroxime axetil for children or
pregnant mothers
Control
 Avoid woody, bushy areas with lots of grass
 Use 20-30% DEET insect repellent and/or Permithin
 Tick Check!
 Cover your skin
References
 CDC.gov/lymedisease
 Roberts, Larry S. "Foundations of Parasitology." New
York: The McGraw-Hill Company, 2009.
 Mayoclinic.com/lymedisease
 http://cal.vet.upenn.edu/projects/parasit06/life%20cy
cles/tick_site/animlife.htm