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Spinal Fluid
- -clear fluid surrounding the brain and spinal cord
- -Allows brain to “float” and reduces its weight
- -Protects brain and spine from injury (impact)
- -Normally clear, when infected with bacteria, can be yellow and turbid (bacterial meningitis)
- -Can also get viral meningitis, but is usually less severe
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Bacterial Meningitis
- -Can result in brain damage, hearing loss or learning disabilities
- -Symptoms: high fever, headache, stiff neck, rash due to immune response (in newborns: head swelling, stop feeding, crankiness)
- -Diagnosed by growing bacteria from a sample of spinal fluid
- -Can be treated with antibioticsSpread through fluids (coughing, kissing, sneezing)
- -Fatality is around 15% with treatment of antibiotics
- -Vaccines are currently available against many types of meningococcal disease (recommended for college-aged students)
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Inhalation
- -Infectious droplets from cough, sneeze, etc.
- -Ex: Flu, TB, colds
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Ingestion
- -Germs get on your hands, then on food, skin, etc.
- -Unwashed produce, contaminated meat, etc.
- -Ex: Salmonella, E. coli
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Direct Contact
- -Spread directly from one person to another
- -Ex: HIV, gonorrhoea
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Indirect Contact
- -Spread via fomites (inanimate objects harboring germs)
- -Ex: tissues, doorknobs, toilets, phones
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Animal Vectored
- -Transmission through insect bite (flea, tick, mosquito, etc.)
- -Ex: Malaria, Lyme disease
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Normal Flora
- – normal microbial growth found in healthy person
- -Usually found in GI tract, mouth, skin, upper respiratory tract
- -Aide in digestion of food, vitamin production, protection from pathogens
- -Can cause disease if invading normally sterile area
- -Ex: E. coli and other bacteria in gut (>2 lbs!)
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Opportunistic Pathogen
- – normally harmless bacteria that cause disease when host immunity is lowered
- -Ex: C. albicans infections
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Virulent Bacteria
- -growth occurs at expense of host
- -Occurrence of disease determined by bacterial strain, inoculation size, site of entry & host factors
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Bacterial Entry
- -Must get through natural barriers
- -usually through tear in skin, tumor or ulcer in bowel
- -S. aureus & S. epidermidis (normal skin flora) cause problems with catheters and IVs
- -Can enter through natural openings (mouth, nose, ears, eyes, urogenital tract, anus)
- -Protected by mucus & ciliated epithelium, antibacterial secretions in tears & mucus, acid & bile in GI tract
- -Can then travel through bloodstream to other sites in body
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