Outbreak Flashcards
What is the difference between colonisation and infection and what microbial and host factors lead to an increased risk of infection?
Colonisation = microorganisms are present at a body site but doing no harm and causing no symptoms
Infection = microorganism invades and multiples in the body tissues resulting in signs and symptoms
Microbial factors = capsule, enzymatic activity, toxins, resist complement
Host factors = very young, very old, current disease, immunocompromised, immunosuppressed, chemotherapy
What are the main modes of transmission of microbes and which microbes are transmitted by which route?
Indirect contact
Direct contact
Inhalation
Ingestion
What is the chain of infection and what ways can break it?
Infectious agent (eg bacteria, virus, fungi, prion) -> reservoir (eg humans, equipment, environment, food, animals) -> portal of exit (eg blood and body fluids, skin scales/wound, coughing and sneezing) -> mode of transmission (eg direct or indirect, inhalation, ingestion) -> portal of entry eg (skin/surgical wounds, eyes or mouth, respiratory tract, intestinal tract, tubes) -> susceptible host (eg underdeveloped immune system, decreased immune system, drugs or disease, tubes) -> infectious agent and so on
BREAK THE CHAIN
Agent - diagnose and treat
Reservoir - cleaning, sterilise, disinfect
PoExit - hand hygiene, PPE
MoTransmission - hand hygiene, PPE, food safety, cleaning, isolation
PoEntry - hand hygiene, PPE, first aid, remove tubes
Host - immunise, treatment, education
What is meant by: cleaning, disinfection and sterilisation?
Cleaning = physical removal of organic material and decrease in microbial load
Disinfection = large reduction in microbe numbers
Sterilisation = removal/destruction of all microbes and spores
How do you identify and control an outbreak?
Outbreak is defined as 2 or more cases of an infection linked in time and place
- Detect
- Find cause
- Likely source
- Test hypotheses
- Solve point of spread
- Control contact with agent
