W3 15 Prevention Of Infections Flashcards
What is transmission?
The movement of pathogens from a reservoir to a host
What is a reservoir?
The habitat in which the pathogen usually lives. Might be humans, animals, environment.
What is the host?
The final organism in which the pathogen received nourishment and shelter
What is a carrier?
Might be infected but asymptomatic, eg hep B
Give some human reservoirs
Blood borne viruses
STIs
Measles and mumps
Some respiratory pathogens
What is zoonosis?
When an infection spreads from animal to humans
Examples of zoonosis
Rabies, Brucellosis, anthrax
Examples of environmental reservoirs
Eg tetanus can live in the soil, legionella is in water sources
What is a chain of infection?
A pathogen can exist in a reservoir where it us not causing any issues, and by a variety of modes it can go onto a susceptible host.
Includes infectious agents, reservoirs, portals of exit, modes of transmission, portals of entry, susceptible host
Examples of direct spread transmission
Direct contact between reservoir and host, eg skin contact, fluid exchange
Droplet spread
Examples of indirect spread transmission
Airborne transmission - eg carried by dust
Vehicle borne transmission - eg food, fomites, water etc on surfaces
Vector borne transmission
Host is the final link in the chain of infection. They must be susceptible. What does contracting the disease depend on?
Genetic factors
Specific immunity - eg protective antibodies, immunisation, previous exposure, vertical transmission
Non-specific factors:
- natural barriers like skin, mucous membranes, cilia, gastric acidity.
- compromise eg alcoholism, malnutrition, immunosuppression
What do patterns of spreading disease depend on?
Population factors - eg genetics, sex, population habits
Pathogen factors - eg requiring specific intermediate host/vector
Environments factors - eg climate, soil
What is epidemiology?
The study of how often disease occur in different groups of people and why
What is public health?
Refers to all organised measures to prevent disease, promote health and prolong life among the population as a whole.
What is an epidemic vs a pandemic?
Epidemic: An increase in the number of cases of a disease that is above what is normally expected for that particular population in a given area
Pandemic: an epidemic that has spread across several countries of continents affecting a large number of people
What is endemic?
The constant presence/usual prevalence of a disease in a population in a given area (eg the flu)
What does sporadic mean?
An infrequent and irregular occurrence of a disease
What is the difference between incidence and prevalence?
Incidence - measure of probability of disease occurrence in a population in a defined period of time
Prevalence - proportion of a particular population found to have a disease
What are some epidemiological approaches?
Define case: a standard set of criteria to classify if a person has the disease
Identifying counts and rates in a population
What study types are there?
Cohort study - group of people enrolled, then determined to have exposure or not. Follow the cohorts to track whether disease is developed.
Case control study - group of people enrolled already with the disease, then comparison group without disease enrolled and previous exposures analysed.
What does an epidemic curve plot?
Number of cases against time
What is an incubation period?
You won’t develop the disease straight away, it takes time for bacteria to multiply and cause disease.
Different patterns shown in epidemic analysis?
Point source - single exposure, no person-person spread
Continuing source - ongoing source of infection
Intermittent outbreak - not well controlled - recurring outbreaks
Single source with delayed control measures
Full blow epidemic - continues until number of susceptible people declines or control measures take place
Preventative measures in public health
Health promotion - eg policies and interventions, advice etc
Disease prevention - eg vaccination,
Infection control in dentistry
Bare measures - pg176 if u want to read
READ THIS LECTURE!
Read rather than memorise tbf
What are answers to most decontamination questions?
HTM 01-05
