Lecture 17 11/7/23 Flashcards
What are the general characteristics of spirochetes?
-slender and helically coiled
-move with corkscrew/flexing motion
-can move in highly viscous environments
-have endoflagella
-gram neg.
-stain poorly
-seen with dark field micro./silver stain
What are the pathogenic genuses of spirochetes?
-Leptospira
-Borrelia
-Brachyspira
-Treponema
What are the characteristics of Leptospira sp.?
-pathogenic
-maintained in renal tubules of reservoirs
-survive in environment
-excreted in urine
-spread through direct contact with urine or contaminated environment
What are the pathogenic species of importance for Leptospira?
L. interrogans
-L. borgpetersenii
-L. kirschneri
What type of disease is seen in Leptospira maintenance hosts/reservoirs?
-infection in privileged sites
-long term shedding
What type of disease is seen in Leptospira incidental hosts?
-recovery with short term shedding
-potential for severe disease
Why is Leptospira infection considered biphasic?
-first phase sees major increase of bacteria in blood before dying down
-second phase sees major increase of bacteria in urine
What are the clinical signs of Leptospira infection?
-broad clinical manifestations that can be mild to severe
-signs of hepatic and renal failure
How can Leptospira sp. be diagnosed?
–microscopic agglutination test:
-serovar with highest titer typically indicated as infecting serovar
-paired titers with 4-fold increase OR single titer > 800
–quick serology tests
–direct fluorescent antibody test
-PCR
Which samples are used for different Lepto. tests?
PCR: blood
PCR: urine
MAT: serum
How can Leptospira be treated?
-supportive care
-antimicrobials; penicillins for severe disease, doxycycline for carriers/post-exposure
How can Leptospira be prevented?
-vaccination
-minimizing exposure to contaminated surface waters
Which Leptospira sp. is host adapted in cattle?
L. borgpetersennii serovar hardjo
What does Leptospira cause in cattle?
reproductive failure due to embryonic death
How is Leptospira diagnosed in cattle?
testing the urine after administration of a diuretic
How can Leptospira be treated and prevented in cattle?
-vaccines
-long acting tetracycline and sustained-release ceftiofur
Which Leptospira serovars are seen in horses?
-Pomona
-Bratislava
-Grippotyphosa
What can Leptospira cause in horses?
-abortions
-systemic illness in foals
-equine recurrent uveitis
How is Leptospira prevented in horses?
vaccination
Which animals act as reservoirs for Lepto?
rodents
Which Lepto. serovars infect pigs and cause repro. failure?
-Pomona
-Bratislava
Which Lepto. serovar infects California sea lions?
Pomona
What are the characteristics of Leptospira as a zoonosis?
-widespread
-underdiagnosed
-febrile illness with renal, hepatic, and pulmonary disease
What type of general disease is caused by the genus Borrelia?
arthropod/tick-borne disease
What does B. burgdorferi cause?
lyme disease
What does B. anserina cause?
avian septicemic borreliosis
What does B. recurrentis cause?
human relapsing fever Borrelia
What are the characteristics of B. burgdorferi lifecycle?
-transstadial transmission during the 2 year lifespans of Ixodes tick
-ticks can only become infected when feeding on host with high level of bacteremia
What are the characteristics of lyme disease in the US?
-most common vector borne illness
-under-reported
-overdiagnosed
What are the characteristics of B. burgdorferi virulence and pathogenesis?
-can hide out as L-forms
-can undergo antigenic switching
-cause a skin rash as a first sign in humans
What are the characteristics of canine lyme disease?
-antibody titer is not indicative of illness severity
-signs include fever, arthritis, arthralgia, and lameness
How can Lyme disease be diagnosed?
-direct detection
-culture and isolation
-PCR
-ELISA
-paired titers
How is lyme disease treated?
doxycycline and minocycline
How can lyme disease be controlled?
-vector control
-vaccination
What are the general characteristics of Brachyspira hyodysenteriae?
-anaerobic
-obligate parasite of pig and mouse colons
-causes swine dysentery
-spread through fecal-oral
What are the characteristics of B. hyodysenteriae virulence/pathogenesis?
-chemotactically attracted to mucin
-invades intestinal crypts and disrupts colonic epithelium
-death from dehydration
-absorption of bacterial endotoxins through damaged mucosa can worsen symptoms
What are the symptoms of B. hyodysenteriae?
-bloody diarrhea
-dehydration
-weight loss
-fibrinonecrotic pseudomembranous colitis
How can B. hyodysenteriae be diagnosed?
-direct staining
-anaerobic culture
-PCR
-histopath/silver staining
How is B. hyodysenteriae controlled?
-specific pathogen free herds
-management/hygiene
-vaccines
What are the characteristics of Treponema pallidum?
-causes syphilis
-reemerging in humans
-cannot be cultivated in lab
What does Treponema cause in cattle?
papillomatous digital dermatitis
What does Treponema paraluiscuniculi cause in rabbits?
rabbit syphilis/vent disease
