M5- Routes of transmission Flashcards
Describe the chain of infection.
- infectious microbe
- reservoir
- portal of exit (leaves reservoir)
- modes of transmission
- portal of entry
- susceptible host
what interrupts transmission?
breaking the chain at any point
Name ways of breaking the chain of infection?
- sterilisation/disinfection
- isolation/PPE
- Decontamination
- Vaccination
Name routes of transmission..
- Contact (direct or indirect)
- droplet (coughing/sneezing/ >5microns
- Airborne (5microns or smaller particles)
- Common vehicle (food, water)
- Vector-borne (malaria, limes disease)
what are the 5 ways any infection can spread?
- Inhalation
- Ingestion
- Inoculation (direct/indirect)
- Mother to Infant (vertical)
- Intercourse (STI or STD
what are infections do to with ingestion usually related to?
- alimentary canal
- gastro-intestinal tract infection
how can infection be ingested?
- water- contaminated with sewage/animal faeces
- food and milk- contaminated during storage
- contact infection-poor hygiene/contamined hands
what are infections do to with inhalation usually related to?
respiratory tract
what is direct inhalation?
Direct Contact (patient to dentist) Saliva/Sneezing/Drill aerosol
what is indirect inhalation?
- (Airborne) spread -droplets contaminate material first
- host makes contact with material
- droplets evaporate to form droplet nuclei
Describe good respiratory hygiene/cough etiquette.
- Cover nose & mouth with disposable single use tissues when sneezing/coughing/ wiping & blowing nose
- Dispose of hand tissue in waste bin
- Wash hands with soap & water after coughing/ sneezing, contact with respiratory secretions.
- Keep contaminated hands away from mucous membranes of the eyes & nose
Describe inoculation.
- injection
- animal vectors (malaria)
- needlestick accidents (hep B)
- contaminated needles (needle reuse ,drug addicts, poor hygiene
How does infection affect skin and mucous membranes?
- direct contact (skin to skin) -STD
- indirect- breach of barrier-cuts,burns,tooth extractions
Describe the mother to infant transmission.
- transplacental (HIV,herpes)
- Birth (contact with surfaces of urinary genital tract & blood (hep B is too big to cross the placenta)
what are standard precautions of ingestion and inoculation?
contact precautions
what are standard precautions of inhalation droplet?
droplet precautions
what are standard precautions of inhalation airborne?
airborne precautions
what are standard precautions of injections?
good practise
sterilisation
sharps management
what is standard infection control?
-All patients pose an equal risk
• Measures employed are effective at minimising or removing risk
• Effective measures are employed at all times
Name the standard control of infection precautions.
• Hand hygiene • Sharps management • Clinical waste • Personal Protective Equipment (PPE) • Patient placement • Body fluid spillages • Environmental cleanliness • Clean equipment • Laundry • Respiratory etiquette
Describe the skin environment.
• Periodic Drying
– dormancy • Moist areas
– scalp, ears, Genito-urinary tract • Acidic pH
• High Salt (hyperosmotic)
• Inhibitory substances
– lysozyme
– cathelicidins (detergent like) – Oleic acid (Gram -ve)
what occurs when skin is not washed/ dried effectively?
concept of transient flora- S.aureus hand carriage
how does skin aerobic bacteria vary?
Varies from individual to individual, but relatively constant for that person
what are the 6 steps of hand hygiene?
- Palm to Palm
- Palms over Dorsum
- Fingers interlaced
- Backs of Fingers to Palms while interlaced
- Rotational rubbing of thumbs in opposite plams
- Rotation rubbing of clasped fingers in palms
what is BBE?
- bare below the elbows in clinical areas
- no neck ties and no white coats
- short sleeves
- no wrist watch , no jewlery
what are reasons for drop in HAIs (healthcare associated infections)?
• hand-washing, either with soap and water or alcohol hand gel in some cases
• use of protective gear, such as disposable gloves and aprons
• regular cleaning to prevent the build-up of organisms
• isolating patients with antibiotic or antimicrobial-resistant
infections, in order to prevent the spread of such organisms
• appropriate use of antibiotics: appropriate use includes using the right type of antibiotic at the right dose and only using them when judged medically necessary
what factors influence disease?
- Agent- (infectivity,pathogenicity,virulence ,antigenic stability, survival)
- Environment- Weather, Housing (density, temp etc.), Geography, Occupational setting, Air quality,Food/Access to nutrients
- Host - age, sex, genetics,behavior, nutritional status, health status (immunocompromised)
what controls pathogens?
innate and adaptive immune systems
Name antibacterial defences.
• Physical Systems – (nasal hair, saliva) • Chemical Defenses • Barriers – (epithelial) • Cellular Replacement – (shedding) • Normal Microflora • Antimicrobial peptides • Acute Phase response • Acquired Immunity
what provides protection at mucosal surfaces?
complement
