Borrelia burgdorferi (Lyme Disease) Flashcards
Borrelia burgdorferi
lyme disease
Transmission by
vectors: Ixodes scapularis and Ixodes pacificus (black-legged ticks)
Structure
motile, gram-negative, obligate parasitic spirochete
Does it infect specific cells
no
How long does it take to transmit the disease?
about 24-52 hours (most optimal time is 36-48hrs)
Transmission Cycle
tick lays eggs-> larvae attach to first host-> acquire disease-> tick molt into nymph -> feed on second host-> molt into adults-> infect incidental hosts or attach to reservoir host for feeding/mating
reservoirs
rodents and white-tailed deer
Incidental hosts
people and domestic animals
Pathogenesis
begins to replicate at site of tick bite-> uses tissue resources to help with this-> causes significant inflammation in the area-> immune system capable of minimizing infection-> moves into joint space-> immune system has poor control there-> can disseminate to other parts like eyes, nervous system, and cardiovascular system
Incubation
2-5 months
Tick distribution
west and east coast (east goes as far as half of texas)
Prevalence of lyme disease in the states
north east
Clinical signs
wild mammals/birds usually asymptomatic
-fever
-anorexia
-lethargy
-intermittent lameness
-swollen joints
-swollen lymph nodes
-rash at tick bite
RARE: facial paralysis, seizures, cardiac arrythmias
Pathologic lesions
-nonerosive arthritis
-Uveitis
-myocarditis
-neutrophilic or lymphoplasmacytic, histiocytic, perivascular to diffuse inflammation
-affects meninges, ganglia, and cranial and spinal nerve roots
-variable necrosis, fibrosis, and neuroparenchymal invasion
Diagnosis
wester immunoblot test
antibody titer:takes 4-6wks to develop readable antibodies, if >1:64 then likely encountered B. burgdorferi
