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130 Cards in this Set
- Front
- Back
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Classification
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a method by which biologists group and categorize organisms by biological type, such as genus or species
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Taxonomy
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science of classification
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Why use taxonomy?
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TO FACILITATE RESEARCH, SCHOLARSHIP AND COMMUNICATION
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3 Domains
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Eukarya, Bateria, Archaea
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What types of organisms are Eukarya?
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animals, plants, fungi and protists
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What types of organisms are Bacteria?
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all pathogenic prokaryotes, many non-pathogenic prokaryotes and photoautotrophic prokaryotes
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What types of organisms are Archaea?
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prokaryotes w/no peptidoglycan in their cell walls, methanogens, extreme halophiles, hyperthermophiles
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5 kingdoms
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Monera, Protista, Fungi, Plantae, Animalia
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What kind of organisms are Monera?
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all the prokaryotes
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What kind of organisms are Protista?
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mostly unicellular, simple, eukaryotic organisms, many kinds
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What kind of organisms are Fungi?
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unicellular yeasts, multicellular molds and mushrooms
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What kind of organisms are Plantae?
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some algae, all mosses, ferns, conifers, and flowering plants – all members are multicellular
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What kind of organisms are Animalia?
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multicellular, sponges, various worms, insects and animals with backbones
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Typical bacteria types
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Gram - cocci, Gram + cocci, Gram - rods, Gram + rods
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Atypical bacteria types
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Acid-fast/nocardioform, mycoplasmas, spirochetes, chlamydias, rickettsias, photoautotrophic
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Properties of Gram - cocci
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rare ones that cause bacterial meningitis and gonorrhea are significant
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Properties of Gram - bacilli
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•enterobacteriacae
o Enteric bacteria (found in intestines) o usually mobile o usually facilitative anaerobe •Coliform – uses lactose •usually non-pathogenic native bacteria •E. coli from cattle can be pathogenic to people •non-coliform – can't use lactose •tend to be pathogenic foreign bacteria |
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Types of Gram - bacilli
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•Salmonella (usually from chickens)
•Vibrio Cholerae •diuretic disease •fast acting very damaging •Psudeomonas •resistant to drugs and heat •found in soil, get dragged into hot tubs •frequent hospital illness •found in hospitals growing in 10% bleach solution – VERY RESISTANT •green growth |
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Fastidious Gram - bacilli
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o Found in entire body not just in intestines
o Very tiny rods with very specific nutrient requirements o “picky eaters” o can be found anywhere in body and in general environment •Haemophilius influenzae: a flu bacteria •Bordetella pertussis: Whooping Cough - can be vaccinated against •effects infants, severe cough, causes cardiac arrest due to inability to breathe •Legionella : Legionnaires disease hangs out in moist air ducts •causes pneumonia like symptoms that can be fatal |
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Properties of Gram + bacilli
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- not many are medically important, has peptidoglycan wall, very abundant in the outside environment, most of them form endospores
•most live in outdoor environments, lakes & ponds & soils •usually spore formers (endospores) |
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non-spore forming Gram + bacilli
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•Corynebacterium diptheriae : Diptheria
•affects children causes swelling that affects breathing •usually found in people but can be found in enviroment •currently common in third world countries due to lack of vaccination •Lactobacillius •lives in intestine •used to make food products •Aerotolerant •Listeria •Pregnant women •crosses placental barrier and causes still birth •listeriosis affects weakened immune systems |
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spore-forming Gram + bacilli
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•Bacillus anthracis : Anthrax
•Cattle based illness •Cutaneous (skin) open sores •inhalation anthrax : severe pneumonia type infection •spores can be weaponized – bioterrorism •Clostridium Botulinum: botulism •Found in soil •obligate anaerobe •forms spores when exposed to oxygen •forms powerful neurotoxin highly toxic •treated via antibiotics and full life support •one of the most powerful known toxins •recovery takes one month to leave hospital and one year to fully recover •Clostridium tetani : tetanus •lockjaw |
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Properties of acid-fast/nocardioforms
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-both gram positive
-lipid layer = mycolic acids (thick waxy layer) -cells grow slowly due to formation of lipid layer (thus difficult to culture) -resistant to immune system due to waxy layer -often absorbed by immune system and hide in macrophages |
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Types of acid-fast/nocardioforms
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•Mycobacterium tuberculosis
•Mycobacterium lepri: leprosy •gets into extremities and eats away at flesh |
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Properties of Mycoplasmas
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•no cell wall
•found in lungs, and very specific stable enviroments •lung types cause pnumonia |
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Properties of Spirochetes
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-helical or coiled form of spiral shape
-will stain Gram - -very fast and motile -borralia disease is caused by ticks – Relapsing Fever, fever that comes and goes, another spirochete -Genus Leptospira, leptosporosis – can cause severe kidney and liver disease -dogs rats and wild animals pick it up and carry it in their urine -easily picked up in natural waters, look for signage |
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Types of Spirochetes
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•Treponoma palladium
•Syphilis can be treated •if untreated it will infiltrate entire body •Causes brain degeneration and sores and a very ugly death •Borrelia spp. •Lyme disease •difficult to diagnose and treat •moves throughout the body •joints,heart, liver, spleen, Bullseye rash on chest •3 months or more to treat constant medication •Borrelia species also cause relapsing fever •Leptospira •found in water or soils •ingestion of water •urination of animals spread it •kidney inflamation |
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Properties of Chlamydias
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•obligate intracellular bacteria
•reticulate bodies (when in cell) •offspring is elemental body •elemental bodies carry infection to other cells •When bacteria is in cell it is invisible to immune system and difficult to detect •Elemental bodies are detectable via immunological (antibody) tests but only in high numbers •some Chlamydia are carried by bird feces •some cause blindness •main form is STD |
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Properties of Rickettsias
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•Gram negative bacteria, rod shaped (coccobacilli)
•obligate intracellular bacteria •transmitted via pests (lice fleas ticks) |
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Types of Rickettsia
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• Epidemic typhus
• poor personal sanitation contributes • lice have bacteria, crap on skin, scratching pulls it into body • Common in wars (ww1&2) • Murrine – carried by rats fleas • Rikettsia (rocky mountain spotted fever) • ticks on deer (caught by hunters when cleaning carcass) • spotted rash |
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Photoautotrophic bacteria
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Type of photosynthesis different from plants
Some use hydrogen sulfide gas instead of water Cyanobacteria (blue green) plant photosynthesis |
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Actinomycetes
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cell can form long narrow filments as extensions of their cell walls or membranes, and they congregate and form a film, thy are in nature, but don’t infect animals or humans – forms a clear film over things, unique because of their shape (filamentous) not medically important
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Parasites
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Anything that lives in or on another organism and causes harm (i.e. takes nutrients)
*Good Parasite has an escape plan (finding a new host) |
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Parasites: Direct life cycle
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• Direct: host → to another host (through environment)
• All Development occurs within host • Host infected • Egg or Oocyst released in feces • environment (water soil food) • Ingestion or penetration |
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Parasites: Indirect life cycle
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• Indirect
• multiple hosts Definitive Host and Intermediate host • Definitive Host (sexual reproduction) Gametes, two parents • Indefinite Host (asexual reproduction) self cloning • Definitive Host (sexual reproduction) • Egg or larvae released in feces or urine • intermediate (Indefinite) host (asexual development) • like insect, snail, fish or crab etc. • returns to environment feces, burrowing or host gets eaten • Ingestion penetration or injection (mosquitoes or fleas) |
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Protozoan parsites: Amoebas - properties
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-don’t have any kind of a shape
-move uniquely in a gliding motion by forming pseudopods (pseudo – fake – pods – feet) streams its body across things by pushing cytoplasm along the surface. -Entamoeba histolitica is one of the many that cause a severe diarrhea and can be terminal. -Amoebae like red blood cells, so they ulcerate your intestines so we stop absorbing nutrients and we get other bacterial infections, and we get severe diarrhea, there are antiparasitic drugs, but they have to be administered properly (because we’re working on eukaryotic orgs in eukaryotic setting). |
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Protozoan parasites: Amoebas - types
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• Entamoeba histolytica
• found in water • like red blood cells • burrow into intestines to get at blood • cause secondary infections in intestines • cause diarrhea and loss of nutrients and fluids • damage to intestines prevents nutrient absorption • Needs to be treated with antiparasitic drugs and antibiotics or secondary infection • Naegleria fowleri • free living organism • likes warm moist environments puddles, hotsprings • can go dormant in unfavorable conditions (dry environment) • not normally a parasite • pathogenic to people via inhalation • when they find themselves in a unfamiliar environment they move • They migrate to the Brain and eat it, fast. • Fatal within 2-3 days • opportunistic parasite, not common or easy to diagnose • wide ranging symptoms, headaches, fevers seizures, • very bad parasite (no escape plan) kills host before transfer |
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Protozoan parasites: Flagellates - properties
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• egg shape undulating membranes or multiple flagella
-it doesn’t wrap around the cell |
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Protozoan parasites: Flagellates -
types |
• Trichomonas vaginalis
• infects genitals (penis/vagina) • nuisance parasite, can eventually damage reproduction • easy to diagnose and treat • Giardia lamblia (intestinalis) • both sexual and asexual reproduction • passed through fecal material • two nuclei make a distinctive appearance • common in all mammals • campers diarrhea • can often be carried without symptoms • concave shape with sucker on inner curve • sucker clamps onto intestinal wall, blocks nutrients • classic signs is fatty material in diarrhea • easily transmissible via unclean hands |
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Protozoan parasites: Hemoflagellates - properties
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“in blood”, all have indirect lifecycles, insects will be the indirect host, we will be the direct host, mostly in South/ Central America
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Protozoan parasites: Hemoflagellates - types
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• Trypanosoma brucci
• Savannah area of Africa • TseTse fly carrier (intermediate host) • causes sleeping sickness • semi-comatose state • move and multiply in blood to brain • sexual reproduction in host, produces oocytes that are transmitted by insects • Trypansoma cruzi → Chaga's Disease • Gets into heart and vicera and is fatal • carried by “kissing bug” • bug bites, and craps on skin. Scratching moves crap into skin with parasite • Letshmania sp. Transmitted via sand fly (arabia) • cutaneous and visceral versions of illness • move through blood -a few cause organ disease |
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Protozoan parasites: Ciliates - properties/type
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o able to move via cillia, and move nutrients around
o Balantidium coli o relatively huge protozoa o gets into intestines and causes diarrhea |
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Protozoan parasites: Apicomplexans - properties
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o round, have an apical complex
o obligate intracellular protozoans o direct and indirect life cycles o apical complex has enzymes to burrow into cell |
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Protozoan parasites: Apicomplexans - types
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o Plasmodium faciparum (malaria)
• indirect life cycle • definitive host is mosquito, intermediate host is human • found all over world in tropical zones • malaria eradicated in US around 1901 • oocysts hatch in mosquitoe and make sporozooites which get injected into people • sporozooites clog up proboscis of mosquito, get blown into blood • migrate to liver, and invade. Tend to burst out all at once • blood cells then get infected and also burst at same time • when blood bursts symptoms are shown • symptoms are recurrent on weekly type cycle • eventually host is killed, but ample time is given to transmit to new host o Toxoplasma gondii • parasite of cats • cat gets infected, produces oocysts in crap, oocycts get airborn and get into animals • birds, rats carry parasite to new cat • litter box carries parasite to people • weakened immune system creates human vulnerability • females who are pregnant on first contact, can infect fetus and cause problems o Cryptosporidium parvum • direct life cycle • obligate intracellular parasite • found in water, very common • healthy people get intestinal flu like symptoms • immunodeficient people get severe symptoms w diarrhea and dehydration • elderly or young also have more severe symptoms |
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Helminths
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worms
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Classifications of worms/ structure
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1)Trematodes (flukes or flatworms - no segments)
2)Cestodes (segmented flat tapeworms) 3)Nematodes (roundworms - no segments) |
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Helminths - properties
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Eukaryotic
Most are microscopic, larval stages are always microscopic, exception: there are some that are long and thin (tape worms) |
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Trematodes - properties/types
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(flukes or flatworms - no segments)
• in US they infect deer and birds • human afflicting Trematodes are found mostly in tropics • Schistosoma (3 types) • rampant in tropic third world • 2 affect liver one affects bladder • Indirect life cycle • intermediate host is snail • adults form in liver and form eggs that are released in feces or urine(bladder type) • eggs hatch in water and search for snail • they burrow into snail until maturity and burrow out • larva swim then search for people, and burrow into people • not fatal, can be treated • debilitating lingering illness • American variety only affects birds and causes a rash when attacking people • |
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Cestodes - properties/types
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(segmented flat tapeworms)
• most tapeworms have indirect life cycles, very few direct • some have 5 segments some have thousands of segments • longest was found in fish (75 meters) • two suckers on head to hold onto intestines and leech nutrients • also sometimes have hooks on heads to cling with • sometimes have suckers sometimes hooks sometimes both sometimes hooks with suckers • head called scolex • each segment (proglotids) has both female and male reproductive organs • segments furthest from head are most mature, when they gather hundreds of eggs they are released • gravid proglotids are released into environment carrying eggs • Proglotids are nutritious and use this to carry eggs into host • larval stages form in muscle tissue in intermediate host and get eaten by primary host • Beef and pork tapeworms are common, beef tapeworms not in US, pork everywhere • smallest tapeworm (5 segments) found in US and affects sheep |
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Nematodes - properties/types
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(roundworms - no segments)
• most numerous of all known organisms (more than insects) • Trichinosis (pork tapeworm) • Hookworms eat red bloodcells • found into south east US • Pinworms • very common, very easy to transfer • females lay eggs at night while host is sleeping • eggs are placed on tip of anus and scratching releases them onto bedding • eggs get tossed airborne and inhaled • Toxocara • dog worm that can be transmitted through placenta • when it gets into people it migrates randomly causing damage • A cat worm when it infects people acts the same only it wriggles around under skin |
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What are the two general classes of fungal organisms?
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Systemic and Cutaneous
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Systemic fungi
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• Histoplasmosis
• found in bats (released in guano) • disturbing feces releases spores • incurable (lifelong) infections • pulmonary symptoms • coccioidiomosis • found in dry areas like Arizona • sever pulmonary illness • not common • often occurs after earthquakes when earth is disturbed • often more lethal than Histoplasmosis • also not treatable |
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Cutaneous fungi
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• Athletes foot or jock itch
• found in showers • likes moist enviroments • hard to treat • easy to transmit • mainly nuisance illness • dermatomicosis • toenail, or fingernail fungus • ringworm (not a worm) • fungal infection that causes raised ringlike sore • very contagious • common among kids in daycare • nuisance illness |
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Viruses: history/properties
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late 1800's existence of viruses was first postulated (Russian scientist Tobacco mosaic virus)
isolated virus via filtration, couldn't see it, but proved that an unseen cause was present Eventually identified via electron microscope Virus means “poison” discovery opened up disease investigation & new field “Virology” not cellular organisms since 1980 and AIDS virology knowledge vastly increased 1.)Acellular, viruses can also attack other viruses Not technically living, issue of much debate Exhibit symmetry 2) 2 major shapes, cylindrical and multifaceted polyhedron 3) obligate intracellular organisms some can survive extreme environments, but only reproduce inside cells pure parasite, no internal organs, hijacks cells for survival 4) made up of protein and nucleic acids. EITHER DNA or RNA viruses use RNA as a hereditary material |
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Viruses: structure
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Structure:
outer surface are proteins called capsomere which form outer coat calles capsid no cytoplasm or substance inside shell, just genetic material (DNA or RNA) some viruses have 1 protein enzyme inside shell Above describes naked viruses Enveloped viruses have cell membrane material outside shell virus leaves cell via budding process and takes cell membrane with it Naked viruses breed to such an extent that they burst (lyse) the cell and enter environment viral classification is based on target organs and effects, shapes and size best classification is type of DNA or RNA RNA or DNA, ss or ds, + or – sense, matched or unmatched ds strands, also types of enzymes, capsids, shape |
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3 types of viruses
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lytic, latent, persistent
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Lytic viruses
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o get in and out fast
o they get copied and cause cell to burst o cold, polio, o fast onset of symptoms o quickly kill cells o usually handled by immune system o polio bad because it targets neurological system |
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Latent viruses
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o get in and out like lytic
o can go dormant when targeted by immune system and persist for years o Chicken pox • can go dormant • attacks again when you get old and causes shingles • they incorporate into cell and become part of cell that is replicated o Herpes • cold sore version • never goes away • activates during times of immune system stress |
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Persistent viruses
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o Worst type
o slowly but continually replicating o initial low level symptoms like minor headache or sore throat • by time of diagnosis it becomes impossible to treat o mono (Epstein Barr Virus) • later causes chronic fatigue system o Hepatitis B&C affect liver (Hep goes up to G) • C is very low level and nasty o Due to low levels, they never trigger major immune response • minor response is infective |
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Steps in Animal viral life cycle
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1) Attachment
2) Internalization – how the virus gets into the host’s cell 3) Uncoating – (viral coat is called capsid) called the eclipse phase, has to be digested away so the viral nucleic acid material can be released, so it can make copies of itself. Proteases in the cytoplasm work on capsomeres and digest into individual proteins, and DNA or RNA is released into the cytoplasm 4) **may or may not occur, depending on the type of virus** Incorporation – what occurs for latent viruses (other types don’t go through this) Now called a provirus. We have 46 chromosomes in each of our cells. The viral DNA or RNA will go thru incorporation and insert itself on different places on your chromosomes in each cell, and it becomes part of your DNA. Latent virus can come out when your immune system is weakened. Some viruses will skip this step. 5) Transcription and/or translation – the early viral genes: these are genes that are going to code for something the virus needs to be copied – information that will code for an enzyme or something it needs. 6) Viral assembly 7) Release – one of 2 ways, through lysis (how naked viruses are produced) or budding – produces enveloped viruses |
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Steps in Bacteriophage life cycle
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They are bacterial viruses, operate in a bacterial cell like viruses do in our cells, but a bit different – there are no persistant bacteriophages.
1) Attachment – receptors on surface of the wall of a bacteria 2) Internalization – no endocytosis or fusion – instead, penetration – attaches to outer wall of bacterial cell, also no uncoating, and only have DNA not RNA 3) **Incorporation (may or may not occur) – if it does, we call it a lysogenic bacteria or a lysogenic cycle, scientists do this to distinguish – now called a prophage 4) Release – only one choice, which is lysis, which means all bacteriophages are naked viruses 5) Transduction |
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True or False:
RNA or DNA viruses can be either single or double stranded in either case |
True
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Properties of single and double stranded RNA
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-Single stranded RNA – has RNA nucleotides: AUGCA (Uracil lets you know its RNA)
- second strand is complementary to the first one when it’s double – stranded - not necessarily hooked together by hydrogen bonds *some viruses will have 2 pieces of RNA in them, but they’re identical, so it’s not “double stranded” -RNA: strands can be either positive sense strands or negative sense RNA |
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+ sense RNA
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gets into your cytoplasm, when your cells see it, to your cells it looks like Messenger RNA, so your cell wants to translate it
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- sense RNA
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Cell only sees it as RNA, so it doesn’t do anything with it
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RNA-dependent RNA polymerase (RdRP)
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an enzyme that catalyzes the replication of RNA from an RNA template. This is in contrast to a typical RNA polymerase, which catalyzes the transcription of RNA from a DNA template
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Discovery of RdRP
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The most famous example of RdRP is the polio virus. The virus is made up of RNA which enters the cell through receptor-mediated endocytosis. From there, the RNA is able to act as a template for complementary RNA synthesis, immediately. The complementary strand is then, itself, able to act as a template for the production of new viral genomes which are further packaged and released from the cell ready to infect more host cells. The advantage of this method of replication is that there is no DNA stage, replication is quick and easy. The disadvantage is that there is no 'back-up' DNA copy.
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- sense RNA cont'd.
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Negative sense viruses have RDRP enzymes included in virus
RDRP copies -sense strand to + and positive strand gets translated by cells to make capsules and enzyme Assembly binds together – sense strand, enzyme and capsule. |
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RNA virus and retrovirus processes of replication in the host cell
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-Double strand viruses get both treatments + and -
-Some double stranded viruses are double + (no double stranded – RNA viruses have been found) -Both strands come with enzyme, Reverse transcriptase (RT) and are called retroviruses -Retroviruses cause leukemia in cats and people, HIV is a retrovirus -Reverse transcriptase modifies DNA with RNA Viral code. -It inserts a DNA template into 1 strand of our DNA and our cell “repairs” it to make it double stranded -Incorporated Virus is called provirus -HIV is a latent virus, it sits dormant for 3-6 months. It allows cell to conduct housekeeping functions -HIV stops intended functions of cell and forces cell to become viral factory -Incorporated DNA makes mRNA which is used by cell to make more viral components -In case of HIV it is a enveloped virus and buds out through cell membrane -Retroviruses reverse the assumed direction of information flow, from RNA to DNA not DNA to RNA -DNA Viruses -SS DNA virus, -Made DS via cell mechanisms -May incorporate or may not -Your Enzymes act on it like it was your own DNA Double Stranded DNA virus: -Even simpler than SS DNA virus as it is already DS -DNA Viruses & Retroviruses easily pass through nuclear membrane |
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Viral self-protection in a host cell
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If a virus is in a host cell it is protected from immune system, only exposure is in transit between cells
Cells can put out markers to signal immune system to kill cell Envelope viruses are almost impossible for immune system to detect |
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Viruses
Cytopathic Effects on Host Cells: Cell Lysis |
(bursting)
• amount of cells and type of cells destroyed determine severity of effects |
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Viruses
Cytopathic Effects on Host Cells: Disruption of cell membrane (budding) |
• As viral particles are produced they bud out and take membrane with themselves
• low levels of budding can be countered by cell mechanisms • High levels of budding diminish the cell • High levels of budding eventually kill cell • virus only keeps cell alive long enough to make lots of copies, • HIV is bad because it targets the immune system cells and invites secondary infections |
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Viruses:
Cytopathic Effects on Host Cells: Accumulation of viruses (inclusion bodies) |
• Clutter the cell environment, slow down cell processes like a traffic jam
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Viruses:
Cytopathic Effects on Host Cells: Transcription and translation of cell's DNA stops |
• Cells have a function, this function is stopped by the virus
• I.e. hormones are not produced |
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Viruses:
Cytopathic Effects on Host Cells: Elicit a harmful immune response |
• cells release indicators that say “I'm infected kill me” to an excessive extent
• this inspires excessive immune response that is itself harmful • excessive response causes symptoms like arthritis • exact mechanism is not fully understood |
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Viruses:
Cytopathic Effects on Host Cells: Some viruses cause cancers |
• Cells are so messed up that they grow uncontrollably
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Prions
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Rogue Protiens (only protein)
not fully understood, can cause other proteins to misbehave Mad Cow disease causes proteins to digest brain tissue Kuru, Borneo affects cannibals - same effects as Mad Cow Disease Can sit latent for many years Very difficult to denature Prion proteins through temperature (high resistance) |
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Viroids
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Only effect plants
like prions, only Rogue RNA(only RNA) |
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Pathogen
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any harmful organism
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Pathogenicity
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ability of a pathogen to cause harm – function of 3 things:
1) function of the number of organisms 2) function of the virulence of the organism 3) function of strength of your immune system |
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Virulence
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number of organisms it takes to cause a problem
low virulence = low numbers of organism kill low virulence = high number of organisms to cause harm |
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Contamination vs infection
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-to come into contact with an organism is contaminated (like on skin)
-infection is when organism begins to reproduce |
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resolution of disease
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person is cured or dies
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Disease
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disturbance of host normal function
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Chronic disease
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slow onset slow symptoms (months to years before onset of symptoms)
often slow progression and resolution frequently results in death due to prolonged symptoms not easy to transmit (bodily fluid exchange) |
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Acute Disease
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spread easily, onset of symptoms is fast hours to a week, resolution usually quick too
common cold, Ebola = acute diseases fast onset, fast resolution get better or die normally responsible for outbreaks |
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Communicable/contagious
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easily transmitted via touch or sneezing or sexual contact
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non-communicable/non-contagious
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not easily transmitted (tetanus) illness acquired from environment
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opportunistic
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native flora that take advantage of weakness to grow out of control and cause infections
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Normal/resident flora
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native microorganisms present in all organisms of a species
immune system does not usually attack resident flora so long as numbers are low and localized antibiotics or illness affects balance of resident flora imbalanced flora trigger immune response |
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transient flora
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wild type organisms that get into body and run amok until they are killed off
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Koch's postulates → Germ Theory of Disease
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One microorganism causes one disease
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Koch's postulates → Germ Theory of Disease - steps
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1) Took blood from infected mice, took blood from non-infected mice, put it on culture media under the same conditions, found bacterial organisms in the infected blood that formed colonies.
2) Needed to get pure isolates, so he took a fresh plate, bacteria from one of the colonies and put them on the plate, and got a bunch of pure (suspected) anthrax bacteria. 3) Infected healthy mice from the pure culture and waited to see what happened. 4) Took samples from newly infected mice, cultured their blood, should find the same bacterial colonies that he infected them with. |
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Reservoirs (for viruses, bacteria, fungus, and eukaryotic parasites)
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place where a virus can exist usually without reproducing until a host is found
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Reservoirs: Humans
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can be reservoirs (carriers) of low level infections
Carriers have a low level of an infection that does not affect them, but can jump to others. Staphlococus aureus (low levels on skin that do not cause harm) Giardia (host is not infected but can contaminate water supplies) |
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Animal Reservoirs
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(Zoonoses)
Zoonoses are carried by animals and can infect humans (bubonic plague, lyme disease) Animals are most troublesome reservoir as exposure to other reservoirs can be controlled through education Animals cannot be controlled, i.e. cockroaches, mice, pets, insects |
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Inanimate Reservoir
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soil, food: meats & fruits and vegetables
parasite can exist or persist in reservoir for months or years |
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transmission from host to reservoir to host:
Direct Contact |
direct physical contact between hosts
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transmission from host to reservoir to host:
Indirect Contact |
uses fomites (inanimate objects that facilitate transmission) doorknob, used tissues, used needles,
airborne Sneezes or coughing that aerosolize and travel through air |
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transmission from host to reservoir to host:
Vehicle Transmission |
through food or water
contaminated food or water like sewage contaminated water or sewage fertilized crops |
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Animal Reservoirs
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(Zoonoses)
Zoonoses are carried by animals and can infect humans (bubonic plague, lyme disease) Animals are most troublesome reservoir as exposure to other reservoirs can be controlled through education Animals cannot be controlled, i.e. cockroaches, mice, pets, insects |
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Inanimate Reservoir
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soil, food: meats & fruits and vegetables
parasite can exist or persist in reservoir for months or years |
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transmission from host to reservoir to host:
Direct Contact |
direct physical contact between hosts
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transmission from host to reservoir to host:
Indirect Contact |
uses fomites (inanimate objects that facilitate transmission) doorknob, used tissues, used needles,
airborne Sneezes or coughing that aerosolize and travel through air |
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transmission from host to reservoir to host:
Vehicle Transmission |
through food or water
contaminated food or water like sewage contaminated water or sewage fertilized crops |
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transmission from host to reservoir to host:
Vector Transmission |
mosquitoes, fleas, ticks, rabid dogs
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Mechanical Vectors
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no reproduction of pathogen inside vector
ex: dog @ picnic w/ pathogen, poops, fly lands on poop and eats, then lands on picnic food and deposits pathogen eggs on food, you get dog’s tapeworm eggs – fly is the mechanical vector that moved the pathogen from one host (dog) to human host (via food) – no reproduction |
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Biological vector
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biological vector there is reproduction of pathogen inside host
ex: Malaria, vector is a healthy mosquito, reproduces in mosquito who has bitten something with malaria, bites a human after, human will get malaria; pathogen reproduced inside mosquito |
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Pathogenesis: Pathogen Steps
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1) Transmission
2) Adherence 3) Invasion 4) Colonization 5) Avoidance 6) Interference |
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Pathogenesis: Host Steps
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1) incubation period (when 1-5 of Pathogen is happening)
2) prodromal period(interference from Pathogen is happening here) 3) full blown illness (interference from Pathogen is happening here) 4) Decline phase (can include death, or in a better case, it’s when the symptoms start to subside) 5) Convalescence (assuming you have survived) it may be very short or very long, may not be symptomatic, but may not have much strength yet, |
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transmission from host to reservoir to host:
Vector Transmission |
mosquitoes, fleas, ticks, rabid dogs
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Mechanical Vectors
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no reproduction of pathogen inside vector
ex: dog @ picnic w/ pathogen, poops, fly lands on poop and eats, then lands on picnic food and deposits pathogen eggs on food, you get dog’s tapeworm eggs – fly is the mechanical vector that moved the pathogen from one host (dog) to human host (via food) – no reproduction |
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Biological vector
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biological vector there is reproduction of pathogen inside host
ex: Malaria, vector is a healthy mosquito, reproduces in mosquito who has bitten something with malaria, bites a human after, human will get malaria; pathogen reproduced inside mosquito |
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Pathogenesis: Pathogen Steps
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1) Transmission
2) Adherence 3) Invasion 4) Colonization 5) Avoidance 6) Interference |
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Pathogenesis: Host Steps
|
1) incubation period (when 1-5 of Pathogen is happening)
2) prodromal period(interference from Pathogen is happening here) 3) full blown illness (interference from Pathogen is happening here) 4) Decline phase (can include death, or in a better case, it’s when the symptoms start to subside) 5) Convalescence (assuming you have survived) it may be very short or very long, may not be symptomatic, but may not have much strength yet, |
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Factors effecting the disease process
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1) Direct damage
2) Toxins -endotoxins: Gram -, lipids (part of the outer membrane of the Gm – cell), heat stable, causes: increased fever, muscle weakness, lowered blood pressure, leading to shock cascade, clot formation leading to thrombosis in legs or lungs -exotoxins: Gram - & +, proteins (released to the outside of the cell), not heat stable, mainly interfere with the way the cell functions, problems arise when they invade nerve or neurological cells, 2 major types divided by cells they invade: 1) neurotoxins (released by bacteria like Clostridium botulinim or tetanus) very small amounts are extremely toxic – Clostridium botulinum neurotoxin is the most dangerous in the world in the smallest amounts 2) enterotoxins (impacts liver or kidney cells, released by bacteria like E.coli) 3) Allergic responses Some toxins stimulate your immune system to overreact, some bacteria, viruses trigger a severe allergic response 4) Cytopathic effects of viruses Using all the cells ribosomes or nucleotides or other parts, keeping the cells from functioning properly, some viruses can cause cancers or strong immune response |
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Prevalence
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the number of people in a population who have a specific disease at that particular time
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Incidence
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the number of people who get sick from that disease in a given period of time
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Mortality
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how many people die
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Morbidity
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how many people are sick
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“Outbreak”
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a few people coming down with a disease in a general area
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Epidemic
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when a large number of people come down with the same disease in a short period of time in a population
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Pandemic
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a worldwide epidemic
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Endemic
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diseases that are always present in a population, ex: malaria in Africa, Southeast Asia and equatorial South America – if an endemic disease began to spread, ex: global warming caused malaria to spread to other areas that don’t have it no, it could become an epidemic or pandemic
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Types of Epidemiologists
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1) Descriptive – look at rates and data of disease, look at mortality and morbidity rates, and factors that affect whether or not the disease is prevalent, like age and race, geography (she used Hawaiians and leprocy, and black people and sickle cell – my Race Equality in Healthcare prof. says otherwise, and showed us data to disprove that those issues are based on “race”, which does not exist, scientifically – it is a human construct), socioeconomic status
2) Surveillance (“analytical” – book calls it emergence? or emerging?) tracking disease for spread and movement, monitor situations that could lead to the disease moving or changing, like monitoring wars (which increases prevalence of disease in all cases) 3) Field – (book calls it ‘case reporting’ Lee doesn’t like this) thought of as the most glamorous type of epidemiologist, investigating disease in the area, trying to educate people in the area about how to prevent the disease, come back and work in Level 4 labs trying to understand and study the virus 4) Hospital (also State and City Epidemiologists tend to work with the Hospital Epidemiologist) = MDs who monitor what diseases come into the hospital, like Hanta Virus, but also outbreak within the hospital |
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Types of Epidemiologists
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1) Descriptive – look at rates and data of disease, look at mortality and morbidity rates, and factors that affect whether or not the disease is prevalent, like age and race, geography (she used Hawaiians and leprocy, and black people and sickle cell – my Race Equality in Healthcare prof. says otherwise, and showed us data to disprove that those issues are based on “race”, which does not exist, scientifically – it is a human construct), socioeconomic status
2) Surveillance (“analytical” – book calls it emergence? or emerging?) tracking disease for spread and movement, monitor situations that could lead to the disease moving or changing, like monitoring wars (which increases prevalence of disease in all cases) 3) Field – (book calls it ‘case reporting’ Lee doesn’t like this) thought of as the most glamorous type of epidemiologist, investigating disease in the area, trying to educate people in the area about how to prevent the disease, come back and work in Level 4 labs trying to understand and study the virus 4) Hospital (also State and City Epidemiologists tend to work with the Hospital Epidemiologist) = MDs who monitor what diseases come into the hospital, like Hanta Virus, but also outbreak within the hospital |
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Disease Cycles - Emergence/Re-emergence:
Sociological |
seasonal activities like start of school
urban crowding (influx from rural areas) lots of people in one place changes in social behavior (increase in sexual activity) |
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Disease Cycles - Emergence/Re-emergence:
Climate Changes/ Natural Disasters |
environmental changes alter habitats allowing vectors to move to new territories
natural disasters change weather patterns or alter habitats (destroy infrastructure like sewers) |
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Disease Cycles - Emergence/Re-emergence:
Political |
Wars & Conflict generate poor living conditions and move people into unfamiliar environments (first world soldiers in third world hellholes)
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Disease Cycles - Emergence/Re-emergence:
Technology |
Useful machines to perform health or food tasks that aren't used or maintained properly
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