Unit 4- Spirochetes Flashcards
Important Genera
Treponema, Borrelia, Brachyspira, and Leptospira
Spirochetes
Spiral, motile, gram neg, transverse fission division, outer sheath, axial filament
Axial Filament
Inserts through proximal hook and runs along protoplasmic cylinder under the outer sheath to act as a flagella and provide motility along a helical path
Staining
Too thin to ID by gram stain, use darkfield, phase contrast, immunofluoresence, or silver
Borrelia
Microaerophilic, slow growing, motile, gram stain, silver stains, giemsa, or darkfield, require LCFA glucose and amino acids for growth, tick intermediate host
Lyme Disease
Borrelia burgdorferi, aerobic and fastidious, low numbers in infected animals, difficult to culture, ixodes tick vectors, reservoir hosts to small rodents
Lyme Pathogenesis
B burgdorferi LPS and peptidoglycan elicit inflammation, peptidoglycan causes arthritis, IL-1 release causes fever, rash, arthropathy, and antibody synthesis
Lyme Persistence
Infection can progress and bacteria remains, autoimmune reaction can contribute
B. burgdorferi Virulence Factors
Phase variation of surface antigens, motility, and resistance to host immunity
Horse Lyme
Uncommon, cranky attitude, sore back, lameness, fever, depression, arthritis, uveitis, encephalitis, fetal death
Dog Lyme
Asymptomatic or symptomatic, fever, lymphadenopathy, inappetence, lethargy, lameness in front legs, CNS infection, renal disease
Cattle Lyme
Rare, lameness, fever, loss of appetite, fetal death
Human Lyme
Days to weeks before rash occurs, systemic infection, fever, fatigue, rash, arthritis, lymphadenopathy, CNS and PNS, chronic arthritis, neurologic symptoms, heart infection
B. burgdorferi Immunity
Humoral immunity, spirochetes killed by antibody and complement, bacterial DNA and autoimmune reaction lead to chronic infection
B. burgdorferi Diagnosis
History, clinical signs, staining, serology, western blot, dogs can be asymptomatic carriers
B burgdorferi Vaccine
Bacterins can cause autoimmune response, subunit vaccines used
Borrelia theileri
Febrile anemia of horses and ruminants, bovine borreliosis, relapsing fever, spread by rhipicephalus hard ticks
Borrelia anserina
Fowl spirochetosis, transmitted by Argas persicus ticks, birds recover in 2 weeks with long lasting immunity
Fowl Spirochetosis Clinical Signs
Septicemia, paresis, paralysis, necrosis of organs and GI, depression, green diarrhea, splenomegaly, hepatomegaly, anemia
B. anserina Diagnosis
Darkfield microscopy on blood smear, isolation in egg embryo or rabbit tissue
B. anserina Vaccine
Serotype specific bacterin
Borrelia coriaceae
Transmitted by Ornithodorus coriacens ticks, epizootic bovine abortion, may be asymptomatic or abortion
Relapsing Fever
Human borreliosis, zoonotic and lice transmission
B vincenti
Vincent’s angina, normal oral flora in humans, ulcerative suppurative infection of mouth, can spread to dogs
Treponema
Anaerobic, foot infections
T. brennaborense
Bovine papillomatous digital dermatitis, strawberry lesions, polymicrobial, bacterin vaccine previously available
Ovine Footrot
May be associated with T. brennaborense, debridement, common reoccurring infection, culling, polymicrobial
T. paraluis-cuniculi
Rabbit syphilis, vent disease, vesicles on genitals and perineum, treatment in humans can lead to Jarisch-Herxheimer reaction
Brachyspira hydrodysenteriae
depression, sleepiness, loss of appetite, bloody diarrhea, swine dysentery, obligate anaerobe, asymptomatic pig reservoir
B. hydrodysenteriae Pathogenesis
Fecal-oral ingestion, colonizes large intestine mucosa, highly motile, invade goblet cells, hemolysin
B. pilosicoli
Swine spirochetosis, similar to hydrodysenteriae
B. hydrodysenteriae Clinical Signs
Mucoid diarrhea progresses, leads to death
B. hydrodysenteriae Immunity
LPS antibodies, bacterins
B. hydrodysenteriae Control
Antibiotics, quarantine new additions, bacterins, all in all out
B. hydrodysenteriae Diagnosis
Progressive filtration of GI extracts and culture on blood agar under anaerobic conditions, hemolytic film
Other Brachyspira
GI infection, mucoid diarrhea and wasting
