GIT microbes Flashcards
What disease is caused by Actinobacillus lignieresii?
‘Wooden tongue’
What are the clinical signs of wooden tongue in cattle?
- Multiple granulomatous lesions around head and neck, commonly have draining tracts with pale discharge containing small, hard, grey-white granules
- Tongue is painful and firm with a wood-like feel to it
- Dysphagia–> weight loss and loss of production
How would you diagnose A. lignieresii in cattle?
-Clinical signs: drooling, firm tongue, weight loss, swelling of soft tissue
-FNA of lesion–> cytology, gram stain
DO NOT SWAB DRAINING SINUS
How does A. lignieresii cause disease?
Endogenous, opportunistic
Invades deeper tissues as a result of trauma to oral mucosa e.g. penetration of oral mucosa by rough food.
Abcesses begin as a firm nodule that may ulcerate
May disseminate via regional lymphatics to internal organs such as lungs
What are the features of A. lignieresii?
- Gram negative coccobacilli
- Facultatively anaerobic
- Oxidase positive
What disease is caused by Actinomyces bovis?
Lumpy jaw
What are the clinical signs of Lumpy jaw in cattle?
- Pyogranulomatous osteomyelitis in mandible (bone is replaced with porous bone laid down in irregular fashion and honeycombed with sinus tracts containing pus)
- Initially painless swelling
- Dislodgement of teeth
- Inability to chew
- Number of fistulas draining to the surface
How would you diagnose A bovis infection in cows?
-FNA of lesion–> cytology, gram stain, culture
DO NOT SWAB DRAINING TRACTS
How does A bovis cause disease?
- Opportunistic pathogens, requires some host compromise to cause disease
- Gains entrance to tissues via dental alveoli or through damaged mucosa
- Bacterial colonies form and trigger suppurative inflammation
- May spread haematogenously –> abcesses, empyema or suppurative serositis
What are the features of A bovis
Gram positive, filamentous branching rods
Facultatively anaerobic
Where do infections of candida albicans typically originate
Candida is normal flora of the buccal mucosa, intestinal tract and vaginal mucosa
What are the symptoms of candida infection in the mouth?
Cream to grey pseudomembrane over tongue, soft palate and buccal mucosa
How does candida albicans cause disease?
Normal flora and so relies on host compromise to cause disease
- Increased numbers due to lack of establishment of normal flora, change in gut flora (e.g. from AB use), break in skin or mucosal barrier
How would you diagnose an infection of C albicans?
Scrapings and culture from cutaneous or mucocutaneous lesions
Culture on KOH wet mounts or gram stain
Can be grown on Sabouraud’s dextrose agar at room temp after 24-48hrs
How would you treat an overgrowth of C albicans?
- Correct predisposing conditions
- May clear spontaneously
- May require treatment with antifungals
What diseases are caused by feline calicivirus?
-Upper respiratory tract disease: lesions of oral cavity (gingivitis, ulceration of tongue and nasal planum and nasal mucosa)
Conjunctivitis
Fever and anorexia
“Limping syndrome”- fever, muscle soreness, hyperaesthesia, limb-shifting lameness
What is the source of infection of feline calicivirus?
Respiratory, oral and conjunctival routes from virus particles on fomites, direct contact or aerosolised droplets
Handlers may carry virus on clothes or hands
Can survive 8-10days in the environment in humid conditions
What are the features of feline calicivirus?
Non-enveloped, single stranded RNA virus Icosahedral symmetry Resistant to detergent based disinfectants, heat resistant Neutralised by pH <3 Replicates in cytoplasm of infected cell
Describe the pathogenesis of feline calicivirus
Cytopathic- replicates in cell cytoplasm, ruptures cell membrane and releases large amounts of virus
Incubation period 2-6 days
Maternal antibodies last until 12 weeks
How would you diagnose an infection with feline calicivirus?
Clinical signs
RT-PCR
Immunohistochemistry
Viral isolation
How would you treat a cat infected with FCV?
Feline omega interferon
Supportive care- hydration and prevent secondary infection; most cases will resolve spontaneously within 7-10 days
How has FCV been controlled in the feline population?
Included in F3 vaccine
Describe the foot and mouth disease virus
Picornavirus
Non-enveloped RNA virus- multiple strains (7 strains)
Cytopathic
How is FMD transmitted?
Exogenous infection
Spread by direct contact or by aerosolised droplets
Infected body fluids: semen, tears, nasal discharge, saliva, urine, faeces, milk, vaginal discharge, aborted foetuses
