Module 2 (Spirochetes) Flashcards
These are a diverse group of pathogens that infect humans and animals.
Spirochetes
What are the 3 genera of Spirochetes?
- Borrelia
- Treponema
- Leptospira
• Arthropod-borne pathogens
• Transmitted by ticks
• Possess a blood-borne phase
Borrelia
Species of Borrelia associated with animal infections.
- B. anserina (fowl spirochaetosis)
- B. theileri (Cattle relapsing fever)
- B. burgdorferi (lyme disease of dogs, horse, and cattle)
- B. coriaceae (Epizootic bovine abortion)
- B. canis (Intestinal diseases of dogs)
- B. hyos (Swine pathogen)
Gram negative but stain well with Giemsa and Wright
Borrelia
Spirals with characteristic motility (darkfield microscopy)
Borrelia
Possess axial fibrils which differ across species
Borrelia
Pathogens possess a linear double-stranded chromosome
Borrelia
Grows well in embryonated eggs
Pathogenic Borrelia
B. burgdorferi can be cultivated in Modified Kelly’s medium at what degrees Celsius?
33°C
They ferment glucose and other carbohydrates; can be either anaerobes or facultative anaerobes
Borrelia
Borrelia reservoir of infection
- Wounds
- Placenta
- Milk
- Urine
- Feces
Transmission of Borrelia
- Through tick vectors
- Trans-ovarian (maternal)
- Cannibalism
- B. anserina
- Carried by Argas persicus (avians)
- Signs: cynosis and greenish diarrhea, paralysis, and anemia
- Findings: Splenomegaly and liver enlargement
- Fowl spirochaetosis and Goose Septicemia
- B. burgdorferi
- Ixodes scapularis, Ixodes pacificus
- dogs, horses, cattle, humans
- sign: skin lesions, arthritis, neural involvement, lymphadenopathy, and abortion
Lyme Disease
What are the virulence factors of Pathogenic Borrelia?
- Muramic acid and ornithine cell wall
- Endotoxins
- Hemolysin
Laboratory diagnosis of Borrelia
Samples:
- liver
- blood
- synovial fluid
- spleen
Preferred culture media:
- chick embryo
Agent Identification of Borrelia
- Demostration in Giemsa-stained blood
- Inoculation at 33°C
- Dark microscopy
- ELISA
- PCR using genus specific DNA primers
Treatment of Borrelia with antibiotics
- Penicillin
- Streptomycin
- Tetracycline
- Doxycycline
- Enrofloxacin
- Erythromycin
Control and prevention of Borrelia
-Tick control
-Ectoparasite control
Organisms found in the oral cavity, intestinal tract and genital regions (humans and animals)
Treponema
Associated with spirochetal infections of pigs which are reportedly immune compromised.
Treponema
Species of Treponema associated with animal infections
- T. hyodysenteriae
- T. suis
- T. cuniculi
- Loosely coiled (darkfield microscopy)
- Gram negative
- Stain well with Romanovsky
- Posses a 26.9 kDa protein responsible for beta-hemolytic activity of some pathogenic forms
Treponema
- Pathogens are obligate anaerobes
- Require organic materials if grown in a closed environment that makes them grow for long periods at temperature of 5 to 25°C
Growth characteristics of Treponema
Reservoir of infection of Treponema
- GI tract of pigs
- Feces of dogs
Transmission of Treponema
Feco-oral route
Diseases associated with treponema
- Rabbit syphilis/ vent disease
- Swine dysentery/ bloody scours
- T. cuniculi
- signs: diarrhea
- findings: ulcers in the genital and perinal area
Rabbit syphilis/ vent disease
- T. hyodysenteriae
- Invades goblet cells of the colon and multiplies in the crypts of Lieberkuhn
- signs: elevated temperature, bloody diarrhea, dehydratio, and hyperkalemia
Swine dysentery/ bloody scours
Virulence factors of pathogenic Treponema
- Lipoproteins
- Outer envelope proteins
Laboratory diagnosis of Treponema
Samples:
- Smears of fecal material, inoculated blood agar
Agent Identification:
- Phase contrast microscopy, dark field microscopy, PCR
Treatment with antibiotics for Treponema
- Organic arsenicals
- Tylosin
- Gentamycin
- Nitrofurazone
- Lincomycin
Control and Prevention for Treponema
Intensified management program
Morphologically and physiologically uniform but serologically and epidemiologically diverse
Leptospira
- Often referred as smallest spirochetes
- Thin spiral microorganisms found in a variety of moist habitats
Leptospira
- Gram negative which is hardly recognizable
- Thin spiral organisms which require darkfield or phase contract
- S or C shaped
- Highly motile
- Contain endotoxin and hemolysin
Leptospira
- Grow aerobic at 30°C
- Growth enhance by the supplementation of 10% rabbit serum (Fletcher’s medium/Stuart broth)
- dinger zone
Leptospira
Reservoir of infection of Leptospira
- Mammalian kidneys
- Birds, reptiles, amphibians, and intervertabrae
- Rodents and wild carnivore (carriers)
Transmission of Leptospira
- Ingestion of milk of infected cows
- Genital excretion from cattle and swine
- Skin to urine contact
Disease associated with Leptospira
- Canine Leptospirosis
- Equine Leptospirosis
- Swine Leptospirosis
- Bovine Leptospirosis
- Leptospirosis in Sheep and Goat
Course of Canine Leptospirosis
- Septicemic, hepatic and renal disease in 1-3 years old dogs
- Liver and kidney are colonized
Types of Canine Leptospirosis
- Icteric type
- Uremic type
- L. popmona
- moon blindness
- mild fever, mild icterus, and abortion
Equine Leptospirosis
- L. pomona, L. icterohemorrhagica, L. bratislava
- marked by abortion and infertility in sows
- septicemia in piglets
- abortion, stillbirth, and infertility
Swine Leptospirosis
- L. hardjo, L. pomona
- marked by abortion (late term) in adults due to fetal death
-fetal retention - Weak calf syndrome
- Milk drop syndrome
Bovine Leptospirosis
Virulence factors of Leptospira
- Cold hemagglutinin (induces auto-immune lysis of erythrocytes)
- Cytotoxin (damages endothelial cells)
- Urease (damages urinary epithelium)
- Hemolytic exotoxin (responsible for hemoglobinuria)
- Agalactica- associated toxin
Laboratory diagnosis for Leptospira
-Blood, urine
Preferred culture media for Leptospira
- Oxalated human blood
- Fletcher’s medium
- EMJH medium
Agent Identification for Leptospira
- Visual examination of wet mouths
- Darkfield and phase contrast microscopy
- Animal inoculation
- Serogical testing
Treatment with antibiotics for Leptospira
- Penicilin
- Tetracycline
- Streptomycin
- Fluoro- quinolones
Control and prevention for Leptospira
-Vaccination of animals
-Sanitation and hygiene
