Module 5 Flashcards
Spread of Disease & Epidemiology
Communicable Disease
Infectious disease that can spread from 1 person to another
Non-communicable Disease
Disease not usually spread from person to person
Use of vectors, displacement of normal flora
Endemic
Always present in the given population
Reservoir of Infection
Site where microorganism persists (where they grow)
Source of Infection
Individual or object from which an infection is acquired
Zoonosis
Infectious disease that can be transmitted from animal/animal products to humans
Vectors, close contact, Direct inhalation/ingestion
5 Portals of Entry
Skin Respiratory Tract Gastrointestinal Tract Urinary Tract Congenital Infections
Respiratory Tract (portal of entry)
pathogens inhaled adhere to mucosal surface
Mechanical respiratory equipment
Wounds
Gastrointestinal Tract (portal of entry)
ingestion of contaminated food or drink
Resist acidic environment of stomach
Low infective dose/ large ingestive number
Specialised structure
Urinary Tract (portal of entry)
When normal flora gain entry to Urinary Tract
Or
Gain entry via secretions through break in skin or mucosal linings
Catheters Sexual intercourse Contains Pili (allows attachment to mucosal cells)
Can disseminate to blood stream
Congenital Infections (portal of entry)
gain access through the placenta
Rubella & HIV
Perinatal (acquired at birth)
Portals of Exits
Usually the same way they entered
URT = Aerosols (can infect others directly or indirectly)
GIT = Faeces
Skin = Dermis is constantly shed
Urogenital = Semen and vaginal secretions
Contact Transmission
Spread of transmission from 1 host to another by contact
Direct Contact transmission
Transfer directly from 1 person to another
Saliva/ secretion
Skin infections
Pus from wounds
Indirect contact transmission
Via a Fomite
Faecal-oral route transmission
pathogens that entered the body via the GI tract and excreted in faeces
Droplet Transmission
Spread of infection in small liquid droplets
Through the air over a short distance (>1m)
common vehicle Transmission
Transmission of a pathogen to a number of people from a common source
Food, water, or a fomite
Airborne Transmission
spread through the air, over distances over 1m from the infected host
Only causes disease if they gain access in sufficient numbers to a susceptible host through a suitable portal of entry
Water-borne transmission
Transmission from contaminated water
Food-borne tranmission
Infectious agent by consumption of food
soilage
Handling
raw foods
storage
Vector transmission
living agent transmitting agent from 1 host to another
Mechanical
Passed via outside of insect’s body
Biological
Breeds with infection (multiplying in the vector)
Epidemiology
Study of occurrence, pattern of spread and method of control
Focuses on the health of the community rathe than an individual
Outbreak of infection
Occurrence exceeds the expected number of cases in a given time or place
Case definition
description of the syndrome
Used to ensure disease is accurately identified
Morbidity
Incidence of disease in total population
Mortality
Deaths from the disease
Incidence
Number of new cases
Seroprevalence
Prevalence of disease in community, determined by the number of people carrying antibodies to the disease at any given time
Index case
First case of the disease in an epidemic
Epidemic
Sudden rapid raise in incidence of disease
Pandemic
Worldwide spread
Notifiable Disease
Any disease that is required by law to be reported to government authorities
3 levels of Prevention
Primary
- Good nutritional health
- Good hygiene
- Safe water supply
- Vaccination
Secondary
- Development of tests for early detection
- Screening programs
Tertiary
- prevention of further complications
