Infectious disease Flashcards
How should swabs for bacterial culture be handled if their is a delay expected?
> 3 hours - transport medium
4 hours - refridgerarion
How long can most aerobes survive in a) tissue and b) fluid
a) 48 hours (refrigeration)
b) 1-2 hours at 20oC, 24 hours at 4oC or 72 hours at 4oC with transport medium
Which viral infection can be associated with inclusions in circulating lymphocytes, neutrophils and erythrocytes in dogs?
CDV
What infections are spread by Ixodes ticks?
Borrelia, Anaplasma, Ehrlich, Babes, Bartonella, tick-borne encephalitis
Describe the life cycle of borrelia
Transstadial, not transovarial transmission in ticks
Ticks have 2y life cycle
Eggs hatch outdoors, larvae attach to birds/mice/small mammals and become infected
Overwinter, become nymphs, infect birds/mice/small mammals/dogs/deer/people next spring
Nymphs feed, moult and emerge the following autumn and transmit to third host - often larger mammals
How does Bb develop following a tick bite?
Migrates interstitially, hides with collagen and fibroblasts
Does not circulate in blood or body fluids
How do Bb and tick-borne relapsing fever infections vary?
Bb generally does not circulate in the blood or body fluids
What % of dogs seropositive for Bb have signs of lameness?
<5% - although suggested that 40% are false +ves, true number may be nearer <3%
What % of dogs seropositive for Bb have Lyme nephritis?
<2%
What are the 5 Lyme antigens?
OspA - vaccines, also host
OspC - increased 2-3 weeks after exposure, declined after 3-5 months, some vaccines
OspF - rises 6-8 weeks after exposure, persists
p39 - 88% naturally exposed
SLP
What are the members of the mycobacterium tuberculosis complex? What are their main reservoir hosts? Which affect dogs/cats?
M. bovis (C, D) - cattle
M. microti (C) - field voles
M. tuberculosis (C, D) - humans
What is the main risk factor for M. microti infection?
Hunting rodents
What are the routes of infection for tuberculous mycobacteriosis?
Skin, GI, respiratory tracts
What are the most common manifestations of TB in cats?
SC masses with draining tracts and regional lymphadenopathy, with non-specific systemic signs
What are the most common manifestations of TB in dogs?
Non-specific - lethargy, anorexia, weight loss, cough, dyspnoea, v/d, pyrexia
How is TB infection confirmed?
Demonstrating acid-fast bacteria on histo
Culture
How is TB treated in cats?
Surgical debridement
2 months rifampicin, FQ + clarithromycin/azithromycin, followed by 4-6 months of rifampicin and FQ or macrolide
What are the saprophytic mycobacterial species in dogs and cats? How are they classified?
Rapid growing - M. fortuitum, M. smegmatis (C)
Slow growing - M. avid (D/C)
How do slow and rapid growing saprophytic mycobacteriosis present?
Slow - local/systemic gramulomatous disease - weight loss, vomiting, diarrhoea, dyspnoea. Peripheral lymphadenopathy and pyrexia
Rapid - diffuse infections, panniculitis of ventral abdomen
How is saprophytic mycobacteriosis diagnosed?
Acid-fast staining, PCR
How does treatment of saprophytic mycobacteriosis differ from that of tuberculous disease?
Greater resistance to treatment
How do leproid syndromes present? Are they reported in cats or dogs?
Discrete cutaneous lesions.
Both
How is feline leprosy transmitted?
Rodent bites
When is feline leprosy more common?
Colder months