23 - Brachyspira and Lawsonia Flashcards
Lawsonia intracellularis microbiological characteristics
- Obligate INTRACELLULAR parasite
- Can’t be grown outside of cell culture
- Biocontainment level 2
- *PCR
Brachyspira spp microbiological characteristics
- Aerotolerant anaerobe
- Do NOT typically form colonies
- Challenging to grow
- Biocontainment level 2
- *varying degrees of hemolysis
- *Treponema spp. closely related to it: similar growing requirements
- *PCR
Natural host or habitat of Lawsonia intracellularis
- Obligate intracellular organism
- Lives IN THE ENTEROCYTES of hosts
Natural host or habitat of Brachyspira spp.
- Found in GIT of many species
o Domestic and wild birds
o Pigs
o People
o Rodents
o Dogs
Lawsonia intracellularis virulence factors
- Type 3 secretion systems
- Very little known
Brachyspira spp. virulence factors
- Speculation, but poorly defined
- Flagella: SEE SWIMMING ON A WET MOUNT
- Chemotaxis: attracted to mucouos
- Hemolysins?
- *bacteriophage attack!
What does Lawsonia intracellularis cause in pigs?
- Proliferative enteritis (ileitis)
o Corrugation of mucosa!
What are the multiple forms of Lawsonia intracellularis disease in pigs?
- Intestinal adenomatosis: hyperplasia of crypt epithelium
- Necrotic enteritis
- Regional ileitis
- Proliferative hemorrhagic enteropathy: *can resemble swine dysentery
What does Lawsonia intracellularis cause in horses and what does it commonly affect?
- Proliferative enteropathy
- *weaning foals (4-6months)
What are the clinical signs seen in horses with Lawsonia intracellularis?
- Weight loss
- Diarrhea
- Colitis
How is Lawsonia intracellularis transmitted?
- Fecal oral route
Lawsonia intracellularis horse and pig strains
- UNKNOWN whether they are the same
What does Lawsonia intracellularis cause in hamsters?
- ‘wet tail’
o Diarrhea, dehydration
o Anorexia
o Death - *devasting outbreaks in large colonies (ex. pet store)
What does Lawsonia intracellularis usually affect in hamsters? (age group)
- Weanlings (3-8 weeks)
What do you treat Lawsonia intracellularis with and how do you control it?
- Antimicrobials and aggressive rehydration
- *isolate affected animals
What do B. hyodysenteriae and (B. hampsoni) cause in pigs?
- Swine dysentery
- Incubation period: 3-7days (experimentally)
- *see spirochetes in fecal smear
What are the clinical signs with Swine dysentery?
- *diarrhea: mild and watery to muco-hemorrhagic
- Inappetence
- Pyrexia
- Mortality in peracutely affected animals
- *most commonly see in older pigs (grower finisher)
What is the difference in disease associated with B. hampsonni vs. B. hyodysenteriae?
- SAME
o B. hampsonii is less SEVERE
How can you control Swine dysentery?
- Unclear where it comes from (carriers, wildlife?)
- Antimicrobials in affected herds
- NO effective vaccines
What does B. pilosicoli cause in pigs?
- Spirochetal colitis
o Less severe than swine dysentery - *typically self-limiting
What does Spirochetal colitis (B. pilosicoli) look like in finishing pigs?
- ‘wet cement’ feces WITHOUT blood
What does Spirochetal colitis (B. pilosicoli) look like in younger pigs?
- Severe diarrhea (watery or mucoid)
What is a major concern with Spirochetal colitis (B. pilosicoli) in pigs?
- Poor feed efficiency
What are the ways to control Spirochetal colitis (B. pilosicoli) in pigs?
- Antimicrobials
- NO vaccine
- Generally good management practices (AIAI, control other diseases)
Brachyspira alvinipulli (domestic poultry)
- Associated with wet feces
- Diarrhea, green-yellow frothy cecal fluid
Brachyspira pilosicoli (domestic poultry)
- Colonization of cecum associated with mucosal thickening
Brachyspira hyodysenteriae (domestic poultry)
- Severe, necrotizing typhlitis in juvenile rheas (ostriches)
What does Brachyspira spp. (B. pilosicoli and B. aalborgi) cause in people?
- Intestinal spirochetosis
Where is Brachyspira spp. affecting people most common?
- 30% of people colonized in DEVELOPING
- Developed countries
o Children, HIV, MSM (men who have sex with men)
What are the clinical signs you can see INFREQUENTLY with intestinal spirochetosis (from Brachyspira spp.)?
- Associated with GIT (non-specific)
- Chronic diarrhea
- +/- blood
- Cramping
- Colitis
- *use histology (NOT culture)
What can cause digital dermatitis in cattle?
- Treponema spp.
- *likely polymicrobial
What are the 2 presentations with digital dermatitis in cattle (Treponema app.)?
- Proliferative (hairy heal warts)
- Erosive lesions
What does digital dermatitis in cattle suggest? (Treponema spp.)
- Management problem
o Standing in wet material=predisposed
o Maceration of skin FACILITATES infection
What can be done to control digital dermatitis in cattle? (Treponema spp.)
- Early lesions: topical (washing)
- Topical antibiotic if more severe (oxytetracycline or lincomycin/spectinomycin)
Sample collection and handling: Lawsonia intracellularis
- Feces, RECTAL SWABS (actually rubbing the epithelium)
- *Ileal tissue collected at necropsy
- *do NOT freeze
Sample collection and handling: Brachyspira spp
- Rectal swabs
- Colonic or cecal tissues collected at necropsy
- *do NOT freeze
o Key to grow it, but less critical for molecular tests
Sample collection and handling: Treponema spp
- Swaps or tissue to microscopy
- *do NOT freeze
Lab ID: Lawsonia spp
- Histological examination (silver stains)
- PCR or feces or ileal/colonic tissues
Lab ID: Brachyspira spp
- Microscopy of fecal smears
- Culture
- PCR based assays
- *Sequencing is gold standard for species level ID
- Histological examination of cecal/colon
Lab ID: Treponema spp
- Microscopy
Zoonotic and interspecies transmission
- Poorly understood
o Study of human infections not studied (Brachyspira spp.) - *transmission between animals seems likely
o ROLES OF WILDLIFE in agricultural settings - Ex. Snow geese in Nunavut had Brachyspira similar to the porcine strains
o Possible contact with pigs (summer in artic, winter in US Midwest)
Treatment options: Lawsonia
- Susceptible testing IMPOSSIBLE (obligate intracellular parasite)
- Therapy relies on MACROLIDES/PLEUROMUTILINS
What drugs are INEFFECTIVE to treat Lawsonia?
- Penicillins
- Bacitracin
- Aminoglycosides
- Virginiamycin
- Ionophores
Treatment options: Brachyspira
- Pigs: treatment relies heavily on PLEUROMUTLINS and MACROLIDES
- Lack standardized methods
o Have come up with agar dilation susceptibility test method (LABOR INTENSIVE)
