✓ ~~~- Agents that cause disease
- Enter the body through various openings
Biodiversity
✓ ~~~The variety of life in the world or in a particular habitat or ecosystem
Runoff
✓ ~~~Water that flows over the ground surface rather than soaking into the ground
Raw vs. Treated Sewage
, ✓ ~~~Raw sewage:
- Untreated wastewater that contains human and animal waste, as well as other
contaminants such as chemicals, oils, and debris
- Can contain harmful pathogens that can cause disease in humans and animals
Treated sewage:
- Undergone a process of physical, chemical, and biological treatment to remove
contaminants and pathogens
- This process typically includes several stages, such as primary treatment to
remove solids and large debris, secondary treatment to remove organic matter, and
tertiary treatment to remove nutrients and other contaminants. The treated sewage is
then disinfected using methods such as chlorination or ultraviolet light to kill any
remaining pathogens
Industrial Sewage
✓ ~~~Used water from manufacturing or chemical processes
Transmission Routes (airborne, direct contact, insects bites, water or food borne)
✓ ~~~- Airborne: Occurs when infectious agents, such as bacteria or viruses, are spread
through the air in droplets or dust particles that can be inhaled by others.
EX: tuberculosis, measles, and COVID-19.
- Direct contact transmission: This occurs when infectious agents are spread through
physical contact between two individuals. This can include skin-to-skin contact,
sexual contact, or contact with bodily fluids or contaminated objects.
,EX: MRSA, hepatitis B, and HIV.
- Insect-borne transmission: This occurs when infectious agents are spread by
insects, such as mosquitoes, ticks, or fleas. The insect acts as a vector, carrying the
infectious agent from one person or animal to another.
EX: malaria, Lyme disease, and Zika virus.
- Water or food-borne transmission: This occurs when infectious agents are spread
through contaminated water or food. This can happen when water sources are
contaminated with fecal matter or when food is prepared or stored in unsanitary
conditions. EX: cholera, salmonella, and E. coli.
Indicator Organisms
✓ ~~~Different fecal coliform groups are used
- Abundant in feces of warm-blooded animals
- Cost effective to isolate and quantify
- Not perfect!
Indicator Organism Characteristics
✓ ~~~- Non-pathogen
- Have no or minimal growth in water
- Reliably detectable at low concentrations
Total Coliform
, ✓ ~~~Present in the soil and water originating from surface water contamination or from a
warm bodied human and animal waste
Fecal Coliform
✓ ~~~- Subset of the total coliform group
- From the gut and feces of warm-blooded human and animal (mainly E. coli)
Enterococci
✓ ~~~- From the gut and feces of warm-blooded human and animal
- Survive longer than fecal coliform (E. coli)
E. Coli
✓ ~~~A gram-negative --> coliform bacteria
Membrane Filtration Technique
✓ ~~~- Filter used to trap bacteria
- Filtering apparatus
- Filtered bacteria placed on media for incubation
Defined Substrate Test
✓ ~~~- Water sample mixed with media sealed in a tray, incubated for 24 hours.
- Coliform bacteria hydrolase substrate (ONPG) with the enzyme B-D-galatosidase
producing yellow nitrophenyl
- E. coli present reacts with flurogenic substrate (MUG), producing a fluorescent end
product under UV light
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