Environmental Factors Flashcards
6 Examples of environmental risk factors
Air
Water
Soil pollution
Chemical exposures
Climate change
Ultraviolet radiation
3 Top causes of environmental related deaths due to microorganisms
Diarrhoeal diseases
Respiratory infections
Malaria
4 Abiotic environmental factors
wind
water
inhalation of spores
entry into skin
What are the 3 common ways pathogens are spread from one person to another?
Direct contact
Respiratory aerosols
Faecal-oral transmission
What are the 3 main categories of how we become infected by the microorganisms in the environment?
Natural phenomena or disasters bring individuals in contact with opportunistic pathogens
Human activity brings people into contact with opportunistic pathogens
Human activity contaminates the environments with the pathogens
Where do potential pathogens originate from natural disasters?
From dust storms which damage the respiratory airway
From earthquakes which destroy public health systems
From storms which lead to severe flooding
Describe Vibrio vulnificus (4 things)
Aquatic organism
halophile
gram -ve
comma shaped
What 2 types of infections does Vibrio vulnificus cause and where do they occur?
- Wound infections
- Fulminant sepsis
- occur in areas where water temperature remains high all year
What type of wound infections does Vibrio vulnificus cause? (4)
cellulitis - infection in deeper layer of skin
oedema - swelling due to build up of fluid
erythema
necrosis
What % of individuals get fulminant sepsis from Vibrio vulnificus
5%
Vibrio vulnificus is associated with the..
Consumption of raw shell fish
Describe Legionella pneumophilia
ubiquitous aquatic saprophyte
found in lakes, rivers and streams
thin
pleomorphic
gram-ve
bacillus
obligate aerobe
What does pleomorphic mean?
changes, morphology, reproductive and other metabolic behaviours in response to environmental changes
What is an obligate aerobe?
Fussy about nutrition
hard to grow
will only grow in the presence of oxygen
What is a primary pathogen + examples
A pathogen whose role is to cause disease
example S. aureus
What is an opportunistic pathogen?
A pathogen that is not really mean to cause disease but will do in the right environment
example V. vulnificus
What is a viable pathogen?
A pathogen that is not dead but may not necessarily be able to cause disease
metabolically inactive
What are spores?
Tough structures designed to survive tough/harsh environments
How does human activity contaminate the environment with pathogens? + examples (2)
Healthcare environments are reservoirs of pathogens
example MRSA
Poverty, deprivation and overcrowding
example of how poverty, deprivation and overcrowding lead to disease?
inadequate sanitation leads to faecal contamination of drinking water and cholera outbreaks
What is Hepatitis E? (5)
viral infection
asymptomatic
mild-severe fulminant hepatitis
typically self limiting, no treatments required
typically waterborne but can be foodborne
How does Hepatitis E spread?
Faecal-oral transmission
What are the symptoms of Hepatitis E? (4)
Nausea
Loss of appetite
Jaundice
Dark urine
What is infection of Hepatitis E linked with?
Consumptions of pork products
What is the strategy to reduce diarrhoeal disease?
increase access to safe water
provide adequate sanitation
promote hand washing
What is the strategy to reduce acute respiratory infections?
use clean technologies and fuels for domestic cooking, heating and lighting
Viable microorganisms are normally found..
in the atmosphere up to 3km above land
4 reasons why the atmosphere is a harsh environment for microorganisms
UV radiation of sunlight
Low/high humidity
Extreme temperature variation
Pollution
Why can microorganisms encountered indoors be beneficial to our health? (2)
organisms are believed to train the immune system
too clean environments are linked to increased incidence of allergies and autoimmune diseases
Why can microorganisms encountered indoors be detrimental to our health?
potential pathogens are shed from occupants (both human and animal)
Is the diversity and concentration of microorganisms greater indoors or outdoors?
Indoors
4 examples of fungi that are abundant indoors + fact
Aspergillus
Penicillium
Alternaria
Fusarium
- increases with age of dwelling and presence of a cellar
3 examples of bacteria that typically shed from skin
Staphylococcus
Streptococcus
Organism typically found in faeces (home)
Bacteroides
4 Organisms associated with domestic animals
Prevotella
Porphyromonas
Moraxella
Bacteroides
How soon can microbiota changes be observed in a household when moving in/out?
Within days
In what environments are microorganisms in the air important? (4)
Hospitals
Facilities that manufacture medicinal drugs
Manufacturers of implanted medical devices
Factories producing food stuffs
In what environments are microorganisms in the air important? (4)
Hospitals
Facilities that manufacture medicinal drugs
Manufacturers of implanted medical devices
Factories producing food stuffs
Microorganism - Myobacterium tuberculosis
Disease - Tuberculosis
Microorganism - Bordatella pertussis
Disease - Whooping cough
Microorganism - Neisseria meningitis
Disease - Meningitis
Microorganism - Corynebacterium diphtheriae
Diphtheria
Microorganism - Streptococcus pyogenes
Disease - Pharyngitis (sore throat)
Microorganism - Legionella pneumophilia
Legionnaires’ disease
Microorganism - Aspergillus fumigatus
Aspergillosis
2 impacts of air pollution - respiratory disease
damages the airways or causes chronic respiratory disease
damage of chronically diseased airways predisposes individuals to respiratory infections
Example of a primary respiratory pathogen transmitted by air
Myobacterium tuberculosis
What is Myobacterium tuberculosis linked to? (3)
pollution which causes damaged lungs
malnutrition which increases an individual’s susceptibility to disease
overcrowding which facilitates transmission of aerosols
Respiratory aerosols are…
air borne droplets which are usually generated by talking, coughing, spitting and sneezing
Example of an environmental, opportunistic pathogen transmitted by air
Aspergillus fumigatus
Describe Aspergillus fumigatus
approx 250 species but less than 20 cause human disease
ubiquitous in the environment
Where does Aspergillus fumigatus grow? (7)
soil
on plants
in decomposing organic matter
dust
damp
buildings
air conditioning systems
Where are Aspergillus fumigatus spores found? (4)
indoors
outdoors
in water
on food
How does Aspergillus fumigatus affect immunocompromised patients?
they are at greater risk of serious invasive life-threatening infections such as invasive aspergillosis with a mortality rate of 50-100%
How common is invasive aspergillosis?
it is rare in healthy people
What are the risk factors for invasive aspergillois? (3)
- a lung condition - eg asthma, CF or COPD
- weakened immune system - eg following organ transplant surgery or having chemotherapy
- had TB in the past
Can aspergillosis be contracted from someone else or from animals?
No, it is a non-communicable infection
What are the symptoms of aspergillosis? (6)
- shortness of breath
- a cough - may cough up blood or lumps of mucus
- wheezing (whistling sound when breathing)
- a high temperature of 38C or above
- weight loss
- if pre-existing lung condition, existing symptoms may get worse
