Lecture 5 & 6 Flashcards
List 3 broad sources of infectious agents.
Environment
(also Nosocomial)
Other animals (also vertical transmission)
Self (endogenous e.g latent viral infection, opportunistic commensal org. infection)
Also: iatrogenic,
What does ‘secondary viraemia’ mean?
Virus has entered circulation and is replicating in vascular sites
What is the most common site of viral entry?
Mucous membranes
What effect do proteases of GI secretions have on rotavirus?
Cleaves outer capsid; enhances its infectivity
Give one exception to the ‘enveloped-viruses are not resistant to GI secretions’ rule.
Coronaviruses e.g Transmissible Gastroenteritis virus
Other than GI entry, URT entry and transdermal entry, give four possible entry routes for pathogens.
Umbilicus following birth
Genitourinary tract
Mammary gland
Conjunctiva
How does which cell surface the virus buds from influence its virulence?
Apical - can’t cross epithelial barriers this way - less virulent
Basal surface - can easily cause systemic disease
Give two additional factors that exacerbate diarrhoea in young mammals.
Undigested lactose > osmotic diarrhoea
Slower replacement of enterocytes»_space; slower recovery
True or false - viruses infecting the CNS are usually shed from the host in high quantities
False - CNS often a dead end site
What would be an example of microbial disease where no entry is required?
Ingestion of mycotoxins via grain or hay, ingestion of C. botulinum toxin, consumption of water with cyanobacterial blooms
What does ‘common vehicle transmission’ mean?
Contamination of food/water/some other resource that is common to a large number of individuals.
Give two environmental factors that can create an immunocompromised state for an animal.
E.g overcrowding, stress due to noise, nutritional stress (underfed)
