Bacterial and viral pathogens of the bovine GI tract Flashcards
Actinomycosis is a commensal pathogen of which area?
Oral cavity
When is Actinomycosis most likely to cause disease?
More common if cattle fed very coarse feed that can cause damage to the buccal mucosa and gums.
What are the clinical signs/findings with Actinomycosis infection?
Hard, immovable lump (pyelogranulomatous osteomyelitis) on maxilla or mandible.
Initially painless but may become more painful and may ooze small amount of thick pus containing yellow-white granules.
How can Actinomycosis be treated?
- Debridement and antibacterial therapy.
- Oral or iv iodine is most commonly used ± parental penicillin or oxytetracycline.
- Removal of coarse roughage from the diet
Where is Actinobacillosis a commensal of?
The upper GI tract
When is infection with Actinobacillosis most likley?
More common if grazing abrasive pasture plants that can cause damage to the alimentary mucosa.
What are the clinical signs/findings with Actinobacillosis infection?
- Difficulty with prehension and mastication.
- Swelling and abscessation of tongue and draining lymph nodes in cattle and of lips in sheep.
How is Actinobacillosis treated?
Oral or IV iodides
What is another name for laryngeal necrobacillosis?
Calf diphtheria
Describe the aetiology of Oral (necrotic stomatitis) and laryngeal (calf diphtheria) necrobacillosis
- Fusobacterium necrophorum a gram-negative, non-spore forming, rod-shaped anaerobic but aerotolerant organism.
- Commensal of alimentary tract.
What are the clinical signs/findings with Oral (necrotic stomatitis) and laryngeal (calf diphtheria) necrobacillosis infection?
- Fetid breath.
- Necrotic lesions of oral mucosa (necrotic stomatitis) or larynx (calf diphtheria).
- Inspiratory dyspnoea and stridor.
Describe the aetiology of Salmonellosis
- Gram-negative, rod-shaped bacilli
- Major food-borne pathogen of humans
Describe where Salmonellosis infection occurs/spreads in the body, in normal and immunocompromised animals
Infection primarily occurs orally and organisms replicate in the submucosa and Peyer’s patches of the distal ileum and large intestine.
In immunocompromised animals, the organisms spread to the reticuloendothelial cells of the liver, and onto the bloodstream. This can occur rapidly (approximately 15 minutes in calves).
What are the common routes of Salmonella infection?
- Common routes include contaminated feed and environment (soil, birds, rodents, water supplies), and during transport (shedding exacerbated by stress).
- Introduction of a carrier animal into a herd is a common cause of outbreaks.
What are some risk factors for clinical salmonellosis?
Intensification of husbandry and changes that could cause stress (dietary change, pen change, feed withdrawal, heat stress, parturition), heavy grazing of land spread with slurry, contaminated feedstuffs, carrier animals (is there a livery on the farm?) and vehicles.
