Brucella - Spirochetes

• Leptospires are killed by drying, freezing, heat (50C for 10 mins), soap, bile salts, detergents, acidic environments, and putrefaction
• Leptospires persist in a moist, temperate environment at neutral to slightly alkaline pH
• Virulence factors of leptospires

  • Outer membrane proteins
  • Adhesin
  • Hemolysin
  • Endoflagella
  • LPS
  • Heme oxygenase
• Outer membrane proteins


  Interact with host's immune system
• Adhesin


  Adhesion to host epithelium
• Hemolysin

  Hemoglobinuria due to destruction of RBCs
• Endoflagella


  Motility, invasion
• LPS

  Endotoxin, but has reduced activity compared to other Gram-negative organisms
• Heme oxygenase


  Binds with Iron
• Leptospira species

  • Leptospira borgpetersenii
  • Leptospira interrogans sensu stricto
  • Leptospira kirschneri
  • Leptospira noguchii
  • Leptospira santarosai
  • Leptospira weilii
  • Leptospira fainei
  • Leptospira inadae
• Leptospira serovars

  • Hardjo
  • Tarassovi
  • Bratislava
  • Icterohemorrhagiae
  • Copenhageni
  • Pomona
  • Canicola
  • Grippotyphosa
• Hosts and diseases for Leptospira species and serovars

  • Leptospira borgpetersenii Tarassovi - Pigs: Reproductive failure, abortions, stillbirths
  • Leptospira borgpetersenii Hardjo - Cattle, sheep: Abortions, stillbirths, agalactia
  • Leptospira interrogans Hardjo - Human: Influenza-like illness, occasionally liver or kidney disease
  • Leptospira interrogans Copenhageni - Domestic animals and Human: Peracute and Acute disease, abortion in animals
  • Leptospira interrogans Bratislava - Pigs, horses, dogs: Reproductive failure, abortions, stillbirths
  • Leptospira interrogans Icterohemorrhagiae - Dogs, human, Cattle, sheep, pigs: Peracute hemorrhagic disease, acute hepatitis with jaundice, Acute septicemic diseases in calves, piglets, and lambs; Abortion
  • Leptospira interrogans Canicola - Dogs: Acute nephritis in pups, chronic renal disease in adult dog; Pigs: Abortions and stillbirths, renal disease in young pigs
  • Leptospira interrogans Grippotyphosa - Cattle, pigs, dogs: Septicemic disease in young animals, abortion
  • Leptospira interrogans Pomona - Cattle, Sheep, Pigs, Horses: Abortion in adult cattle, Acute hemolytic diseases in calves and lambs, Reproductive failure in adult pigs, septicemia in piglets, Abortion and periodic ophthalmia in horses
• Microbial examination methods for leptospires

  • Direct Microscopy - Dark Field Microscopy, Silver-impregnation stain for histological sections, FAT
  • Growth characteristics - no growth on blood agar or other routine media, Korthof and Stuart broths; Fletcher semisolid medium; Ellinghausen, McCullough, Johnson and Harris (EMJH); Tween 80-albumin medium
  • Animal inoculation - weanling gerbils, hamsters and guinea pigs
  • Serotyping - Microscopic agglutination test (MAT) using known specific antisera
  • Serological tests - MAT, CFT, ELISA
  • Molecular - PCR
• Maintenance and incidental hosts for Leptospira serovars

  • Bratislava - Pigs, hedgehog; Horses, dogs
  • Canicola - Dogs; Pigs, cattle
  • Grippotyphosa - Rodents; Cattle, pigs, horses, dogs
  • Hardjo - Cattle (sheep occasionally); Humans
  • Icterohaemorrhagiae - Brown rat; Domestic animals, human
  • Pomona - Pigs, cattle; Sheep, horses, dogs
• Diagnosis of leptospirosis

  • Clinical signs and Lesions
  • Microscopy (Dark Field Microscopy of Skin scraping lesion, Silver-stained sections) and Bacterial cultures (EMJH medium)
  • Microscopic Agglutination test
  • ELISA, Immunoflourescence Assay, PCR
• Specimens for leptospirosis diagnosis

  • Living subjects → blood, urine, CSF, uterine fluids, placental cotyledons
  • Cadavers → aborted fetus, kidneys, liver, spleen, lung, brain and eye
• Treatment, prevention and control of leptospirosis

  • Antibiotic therapy (Tetracycline (Doxycycline), Fluoroquinolones)
  • Vaccination (Bacterins)
• Other terms for leptospirosis

  • Weil's disease
  • Swineherd's disease
  • Ricefield fever
  • Waterborne fever
  • Nanukayami fever
  • Cane-cutter fever
  • Swamp fever
  • Mud fever
  • Stuttgart's disease
  • Canicola fever
• Borrelia


  • Gram-negative, helically coiled bacteria that ranges from 0.1-3.0 um in width
  • Longer and wider (loosely-coiled) than other spirochetes
  • Possesses linear chromosome, linear and circular plasmids
  • Has low guanine and cytosine content in their genomic DNA
  • Motile - endoflagella
  • Borreliosis have blood-borne phases and can become localized and generalized
• Borrelia are obligate parasites in a variety of vertebrate hosts
• Ticks (Ixodes) are the main reservoir of Borrelia affecting animals
• Small rodents and birds constitute the main reservoir hosts for Borrelia and ticks (Ixodes) acquire infection when larval or nymphal stages feed on these hosts
• Microbial examination methods for Borrelia

  • Direct Microscopy - Dark Field Microscopy, Giemsa stain, or FAT
  • Specimens - blood, spleen, liver smears
  • Growth characteristics (Culture media) - Barbour-Stoenner-Kelly medium, Borrelia anserina → 6-10 day-old fertile chicken or turkey eggs, Borrelia burgdorferi → Modified Kelley's medium
• Borrelia burgdorferi


  Causes Lyme disease/Lyme borreliosis
• Hosts for Borrelia burgdorferi

  • Human and dogs, also reported in horses, cattle, sheep
  • Reservoir host: rodents, lizards, birds
• Transmission of Borrelia burgdorferi

  Tick vector (Ixodes Ricinus, I. scapularis, I. pacificus, I. persulcatus)
• Pathogenesis of Borrelia burgdorferi

  1. Infected tick feeds on susceptible animal and the pathogen enters the bloodstream via tick bites

  2. Multiplication and dissemination throughout the body (joints, brain, nerves, eyes, and heart)

  3. Inflammatory reactions → clinical signs observed
• Diagnosis of Lyme disease/Lyme borreliosis

  • History of tick infestation and typical clinical signs
  • ELISA, Immunoflourescence Assay
  • Microscopy (Dark Field Microscopy) and Bacterial cultures
  • PCR - for low numbers of borreliae in samples
• Treatment, prevention and control of Lyme disease/Lyme borreliosis

  • Acaricide treatment
  • Antibacterial therapy (Amoxicillin, Oxytetracycline)
  • Vaccination
• Borrelia anserina


  Causes Avian spirochetosis
• Hosts for Borrelia anserina

  • Birds (Chicken, turkey, geese, duck, pigeon etc)
• Transmission of Borrelia anserina

  Tick vector (Argas spp.), direct contact with infected bird (blood, tissues or excreta)
• Diagnosis of Avian spirochetosis

  • History and Clinical signs (fever, anorexia, weight loss, paralysis and anemia)
  • Microscopy (Dark Field Microscopy, or Giemsa-stained smears, Silver-impregnation techniques) and Bacterial cultures (embryonated eggs or young chicks)
  • ELISA, Immunoflourescence Assay, PCR
• Treatment and prevention of Avian spirochetosis

  • Acaricide treatment
  • Antibacterial therapy (Amoxicillin, Oxytetracycline)
• Brachyspira

  • Gram-negative, helical bacteria (best viewed under Dark Field Microscopy)
  • Cells are wider, and not as tightly coiled as the Leptospires and can be stained by Aniline dyes or Romanovsky stain
  • Motile (flexing movements)
  • Beta-hemolytic
  • Obligate anaerobes (Brachyspira hyodysenteriae - oxygen-tolerant, growth is enhanced by CO,)
• Sources/Reservoir of Brachyspira

  • Brachyspira hyodysenteriae - Intestinal tract of pigs, wild, rats and mice
  • Brachyspira pilosicoli - Intestines of chickens, dogs, wild birds, rodents and non-human primates
• Virulence factors of Brachyspira

  • Flagella - Confer motility in intestinal mucus to gain access to target cells in the large intestine
  • Haemolysins - Damage to intestinal mucosa, Beta hemolytic in vitro
  • NADH oxidase - Resistance to oxidative damage
  • Lipo-oligosaccharide - Endotoxic effects (inflammatory response)
• Microbial examination methods for Brachyspira

  • Specimens - fecal samples from affected animals showing signs of the disease, deep mucosal scrapings taken from the large intestine
  • Direct Microscopy - Romanovsky stain, Dilute carbolfuchsin, or Victoria blue 4-R, Silver impregnation stain (histological sections)
  • Growth characteristics and Biochemical tests - Trypticase Soy agar with 5% blood and 400 ug/ml spectinomycin at 42°C for 2-3 days under atmosphere delivered by an H, + CO, envelope, Incubated 24-48 hours in an anaerobic environment containing 10% carbon dioxide
• Brachyspira hyodysenteriae


  Causes Swine dysentery / Spirochetal colitis
• Hosts for Brachyspira hyodysenteriae

  • Pigs (weaned pigs from 6-12 weeks of age)