Unit 9 - Infection Flashcards
What are prions?
Misfolded proteins
Normal prions become abnormal and clump in the brain, acuse damage
What are viroids?
Free RNA molecules
What are endogenous acquired infections?
Caused by microbiome (on or in us)
What is exogenous acquired infection?
Bacteria in the environment
What are commensals?
Presence, growth and multiplication of a microorganism that doesn’t interact with host
Rare to cause disease
What are opportunistic infections?
Caused by microorganisms commonly found in environment or flora without harm. Causes infections when defenses are compromised
What is an apparent infection?
Infection that produces symptoms
What is an acute apparent infection? example
<4 weeks with rapid onset
Influenza
What is a subacute apparent infection? example
4-12 weeks slower onset
endocarditis
What is a chronic apparent infection? example
> 12 weeks long duration
tuberculosis
What is a recurrent apparent infection? example
encountered regularly
UTI, thrush, bronchitis
What is a local apparent infection? example
affect one body part/area
tonsilitis
What is a systematic infection? example
affect entire body
sepsis
How does the pathogen come to interact with the host?
Pathogen leave body of infected person
Enter body of susceptible person
Transmission: contact, respiratory, food, waterbourne, faecal-oral, sexual, vertical
Spread: prolif locally, invade, trasnport by blood, nerves, lymph
Infection: overcome defences if compromised or virulence factors
What are mechanisms by which pathogens exploit host and damage?
What is the chain of infection?
Infectious agent
Reservoirs
Portals of exit
Modes of transmission
Portals of entry
Susceptible host
How may the chain of infection be broken?
What are the stages of infection?
What is incubation period?
Time interval between contact with an infectious agent and appearance of the first symptom of disease
What is the infectious period?
Time when infectious agent can be transferred directly or indirectly person-person, animal-human etc
What is latent period?
Period between exposure and onset of infectious period
Can be shorter or longer than incubation period
Where is normal flora present in the body?
Skin
Upper respiratory tract
Oral cavity
Intestine, esp large
Vaginal tract
Where is there an absence of normal flora?
Lower resp tract
Muscle tissue
Blood, tissue fluid
Cerebrospinal fluid
Perioneum
Pericardium
Meninges
What is the benefit of the normal microbiome?
Nutrient production and processing
Competition with pathogenic microbes
Digestion of soluble fibre
Harvesting energy by producing short chain fatty acids
Produce enzymes the body doesn’t
What is symbiosis and the three types?
Interaction between two different species that are in close proximity for an extended period of time
Mutualism - both species benefit
Commensalism - one species benefits, one is neither helped nor harmed
Parasitism - one species benefits, other is harmed
