Disease Prevention Flashcards
Pathogen
Microorganisms that produce disease
Major groups of microorganisms
Bacteria Viruses Algae Protozoa Fungi
Bacteria
Consists of only single cell
Live in temperatures above boiling point and and in cold that would freeze your blood
Normal flora
Harmless bacteria found in the skin, respiratory tract, and gastro-intestinal tract.
They are beneficial and protect the human host by helping with metabolism and preventing entrance of harmful bacteria.
How does infection occur with bacteria?
When bacteria occurring naturally in one part of the body invades another part of the body.
When this occurs, the normal flora are infection causing.
Bacteria shapes
Coccus - sphere
Bacillus- rod
Spirochete- spiral
Spherical - cocci
Streptococci - responsible for strep throat and pneumonia . . . They form into a chain
Staphylococci - meningitis, arthritis, boils/pimples
Rod - bacilli
E. Coli
TB
Salmonella
Spirochetes
Have flexible cell walls and are capable of movement.
Syphilis
Lyme disease
Gram positive
Used in testing, bacteria that are stained by dye and appear dark purple under a microscope
Gram negative
When testing bacteria, bacteria that do not hold the stain and are almost colorless and nearly invisible under a microscope
Aerobes
Bacteria that needs oxygen to grow
Anaerobes
Bacteria that grow in the absence of oxygen and are destroyed by oxygen
Facultative anaerobes
Could live either with the presence or absence of oxygen
Capsules
Protective layer covering cell wall of bacteria
Generally make the bacteria virulent (Apache of causing serious disease)
The capsules increase their ability to resist the bodies defense mechanisms, making them hard to treat with antibiotics
Spores
Some bacteria change into highly resistant spores during harsh conditions
Bacteria remain alive, but are inactive
Can not reproduce or cause disease
When conditions are favorable again, the bacteria become active and capable of causing disease
Spores are the most resistant form of life known
Virus
Smaller than bacteria
Can cause fatal diseases
Invade host cell, replicate itself, then destroys the host cell so the viruses are released into the body
Not capable of growth and multiplication without using cell DNA for host
Latency
Some viruses establish a dormant state in host cell
Can be reactivated in the future.
Algae
Range from single cell organisms to larger cell organisms.
Most algae do not produce human disease
Protozoa
Large group of one cell organisms.
Found in fresh water and marine habitats
Small numbers are responsible for intestinal infections
Fungi
Are plants
Candida - common yeast found in oral cavity
Candidiasis
Thrush
Caused by yeast like fungus in an HIV infected individual.
Prions
Proteinaceous infectious particle
Made of proteins that lack DNA or RNA
Responsible for “mad cow disease” (holes in the brain)
And creuzfeldt-Jakob disease (neurological disorder)
Chain of infection
- Virulence
- # of microorganisms
- Susceptible host
- Portal of entry