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35 Cards in this Set
- Front
- Back
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What hosts does Borrelia burgdorferi infect?
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dogs
cattle horses |
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What disease does Borrelia burgdorferi cause?
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Lyme (Disease) Borreliosis
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What type of bacteria are Borrelia burgdorferi?
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gram negative bacteria with a loosely coiled spirochete morphology
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What kind of stains work best for Borrelia burgdorferi
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gram stain is visible but bacteria is very thin so often use Giemsa, darkfield, immunofluorescence, silver stains, etc.
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What are the atmospheric requirements for Borrelia burgdorferi?
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Microaerophilic (high CO2, low O2)
difficult to grow need special media |
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Borrelia burgdorferi habitat (source)
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highly adapted to arthropod vectors
Ixodes ticks - ixodes scapularis is primary tick vector in the NE and SE USA -Ixodes pacificus is the primary vector in western USA - also Ixodes ricinus and Dermacentor variabilis |
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Reservoir mammalian hosts of Borrelia burgdorferi
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small rodents and deer
--- possibility that dogs might also serve as host ***do not survive in the environment |
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How is Borrelia burgdorferi transmitted?
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acquired via tick bites from adults or nymphs (most aggressive)
therefore there is restricted distribution in the US (where the ticks are) |
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What are the virulence factors for Borrelia burgdorferi?
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1. motility - non-motile mutants can't invade
2. resistance to host innate immunity 3. Endotoxin - none, but does have an LPS analog which elicits inflammation 4. Outer surface Proteins (OSP) - OspA and OspB |
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How do Outer Surface Proteins work as a virulence factor for Borrelia?
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OspA and OspB
-phase variation of surface antigens: delayed immune recognition (~3 weeks) - may play a role with invasion and is also pro-inflammatory |
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What is the pathogenesis of Borrelia burgdorferi?
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- Borrelia enters through tick bite (usually spring and fall)
- initially multiplies in skin - body's defenses can clear the organism, OR enters the circulation and disseminates (slow humoral response helps persistence) -Enters tissues with target organs including joints, LNs, muscle, pericardium, peritoneum, and meninges -inflammation in the target organ leads to clinical signs - at this point, body defenses can clear the organism or organisms can survive intracellularly in target organs with poss. autoimmune rxn resulting in chronic disease |
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What does the LPS analog of B. burdorferi act on?
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monocytes, synoviocytes, keratinocytes --- which causes the release of IL-1
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What diseases do Borrelia burgdorferi cause?
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Lyme Disease in humans and Borreliosis in dogs, horses, and cattle
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What clinical signs do you see in dogs with Borrelia burgdorferi infections?
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exposure may be widespread (serologic surveys)
infections is usually asymptomatic canine dz is milder than in humans and delayed onset signs: fever, inappetance, lethargy, sudden onset of lameness with pain in two or more joints (shifting leg lameness) or ADR |
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What clinical signs would you see in horses infected with Borrelia burgdorferi?
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in endemic areas, 10% or horses may be seropositive
may be asymptomatic signs: fever, lameness (arthritis), sore back *myositis), signs of depression (endephalitis) and blindness (uveitis) -in utero infections may occur resulting in abortion (very rare) or infections in foals obsv. at weaning |
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What clinical signs would you see in cattle infected with Borrelia burgdorferi?
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in utero infections may occur resulting in deaths of calves
one report of arthritis, myocarditis, and pneumonitis in a cow in Wisconsin |
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What clinical signs would you see in humans infected with Borrelia burgdorferi?
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days to weeks after infection (rash around area of tick bite, may contain infection at this point)
weeks to months (infect. becomes systemic; clinical symptoms: fever, fatigue, rash, arthritis, lymphadenopathy, central and peripheral NS) Years- (chronic arthritis and neuro symptoms; infection of heart muscle) |
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Immunity seen with Borrelia burgdorferi
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Antibody Mediated: spirochetes are killed by antibody and complement; but Ab production is delayed -- implications for diagnosis)
Immune Mediated Damage: cross-reactive Ab (autoimmune dz) may be involved in some lesion develop. (heart muscle and CNS lesions) |
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Diagnosis of Borrelia burgdorferi
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-history (geographical area) and clinical signs (+/- response to treatment)
-direct observ. or staining of tissues or fluids (Blood, CSF, joint fluid, urine (pcr if avail.)) -isolation (modified Kelly medium) from skin biopsy or CT (difficult) -serology more reliable than staining/isolation |
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Treatment of Borrelia burgdorferi infections
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-Doxycycline or amoxicillin (30days) -- note anti-inflamm effects of doxy
- Re-eval after 30 d (quantitative C6 to eval response, MBA and UA to assess renal damage) - may retreat IF get intense response on IDEXX SNAP or quant C6 -Macrolides are also effective |
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Control of Borrelia burgdorferi infections
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Tick control - prevent exposure and check for ticks
vaccination Public Health considerations- Dogs may be carriers; animals may also be a source of ticks |
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Brachyspira hyodysenteriae is a major pathogen of what species?
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pigs - relatively uncommon in US
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What type of bacteria are Brachyspira?
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gram negative spirochetes
obligate anaerobes highly motile fastidious growth requirements |
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what is the source of Brachyspira hyodysenteriae
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- can survive several months in manure effluent, but asymptomatic pigs are the major reservoir
- other brachyspira are normal GIT flora |
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What specific disease is caused by Brachyspira hyodysenteriae?
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Acute and Chronic Swine Dysentery in Weanling Pigs
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What clinical signs would you see in Acute and Chronic Swine Dysentery in Weanling Pigs?
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-mild disease may present with mucoid diarrhea with flecks of blood
-acute exposure in susceptible animals can result in severe diarrhea + death (profuse, bloody diarrhea with mucus -dysentery) |
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Treponema is a major pathogen of....
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major pathogen of humans and rabbits
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What are the two species of Treponema we are concerned with?
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Treponema pallidum
Treponema brennaborense |
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What is the source of Treponema spp.?
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normal flora of the oral cavity and rumen (and genital tract)
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What disease does Treponema pallidum cause?
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syphilis
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What 2 diseases are caused by Treponema brennaborense?
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Bovine papillomatous digital dermatitis
Sheep (ovine footrot) |
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Bovine papillomatous digital dermatitis
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heel warts or hairy footwarts in dairy cows
spirochetes are found in SQ and deeper tissues -feet have moist, painful, strawberry-like lesions on skin or chronic, raised wart like lesions ulcerations on heel and around hoof result in lameness |
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How do you diagnose Bovine papillomatous digital dermatitis?
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clinical signs (lesions) and histopathology of biopsies (organisms - silver stain)
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How do you control Bovine Papillomatous digital dermatitis?
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Bacterin vaccine every 6 months
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Ovine Footrot
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may exacerbate the condition caused by Dichelobacter nodosus
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