question

Important features of the domain Archaea

answer

-does not include pathogens
-can survive in many different environments (halophiles=130-150F water, methanogens=animal colons)
-lack peptidoglycan

question

What is endospore formation?

answer

-survival mechanism
-makes the bacteria extremely resistant to outside forces
-this is not a reproductive mechanism

question

Antisepsis (Antiseptic)

answer

Chemicals applied to the body surfaces to destroy or inhibit vegetative pathogens
-must be safe enough to use on skin or other tissues

question

7 major methods of sterilization:

answer

-incineration
-dry oven
-steam/pressure
-ionizing radiation
-gas (ethylene oxide)
-cold sterilization (chemical)
-mechanical filtration of liquids

question

What is degerming?

answer

The removal of microbes from a surface by scrubbing.
examples include:
-washing hands
-prepping skin for injection

*this is better than chemical action and reduces the greatest number of microbes.

question

What is sanitizing?

answer

Disinfection of public places/items. Reduces the number of pathogenic microbes to an acceptable level in order to meet public health standards.

question

What are some practical concerns regarding basic microbial control?

answer

1. Is sterilization required (to meet some public safety standard?)
2. Can the items be reused? or must they be discarded3. can the item withstand control methods4. is the method suitable for the given application? (i.e. harsh chemicals may not be acceptable for use as antiseptics)

question

purpose of room filters:

answer

HEPA filters can filter out pathogens and bacteria from the air.

question

Carl Von Linnaeus

answer

-Composed a system of classification based on observed characteristics
-Standardized naming (binomial, latin)
-defined a species as those who successfully interbreed.

question

Modern Taxonomy

answer

-DNA based
-Phylogenetic hierarchy
-Descending from a common ancestor

question

What is an endospore stain used for?

answer

Identification of clostridium and bacillus. Presence and location of endospore helps to identify the bacterium.
example:
C. Botulinum (terminal)
B. Anthracis (large and central)

question

Factors affecting the death rate of microbes:

answer

1. overall number of microbes
2. the type of microbes
3. Temperature & pH
4. concentration of agent used
5. mode of action of agent (is it cidal or static?)
6. presence of organic matter

question

What is a capsule stain?

answer

An acidic stain is used on the background and a basic stain is injected into the body of the bacteria. The halo in between is the capsule because it does not react to either acidic or basic stains.

question

Describe cell division in prokaryotes:

answer

-reproduce asexually (clone themselves)
-mutations cause diversity, clonal evolution takes place
-conjugation and transformation increase genetic diversity

question

The rapid evolution of prokaryotes increases infectious disease. How?

answer

Mutations will continue to outpace original growth of bacteria. Making it harder to fight with specific antibiotics. Which causes the thriving strain of bacteria to continue to infect a population.

question

Cyanobacteria

answer

-Is an ancestor of the chloroplast
-Participates in photosynthesis (Makes O2)
-Nitrogen fixation is inhibited by O2

*This bacteria may have been the very start of organelles and more complex structures.

question

Who was Joseph Lister?

answer

Used phenol to disinfect before surgery. One of the first to recognize the need to disinfect.

question

Who was John Snow?

answer

Associated known cases of cholera with water borne infection.

question

Who was Alexander Fleming?

answer

Came up with the idea of the magic bullet to fight disease. In this case, he discovered penicillin, which is an antibiotic.

question

Who was Semmelweis?

answer

He was described as the "savior of mothers." He concluded that childbed fever (infections that occurred after childbirth) could be reduced by hand disinfection.

question

Strep. Pyogenes causes:

answer

Causes a variety of human illnesses including:
-strep throat (pharyngitis)
-impetigo (a type of skin infection)
-necrotizing fasciitis
-

question

Brucella abortus:

answer

faculative intracellular parasites that are carried by animals and mostly affect animals, but can be seen in humans.

question

Clostridium Difficile:

answer

Causes severe diarrhea

question

Vibrio Cholerae:

answer

The bacteria that causes cholera

question

Spirillum Minus:

answer

rat bite fever

question

Treponema Pallidum:

answer

the bacteria that causes syphillis

question

Haemophilis Influenzae:

answer

the bacteria that causes meningitis

question

Mycoplasma:

answer

Gram + bacteria with no cell walls, pleomorphic and is part of the class of bacteria that causes walking pneumonia

*Genetically Gram +, but tests Gram - because there is no peptidoglycan.

question

Pleomorphism:

answer

The occurrance of two or more structural forms in an organisms life cycle.

question

Plasmid:

answer

DNA molecule separate from the organism that can transfer information

examples: genes, antibiotic resistance

question

Sanger sequencing:

answer

Also known as DNA sequencing, Sanger developed rapid DNA sequencing because he discovered that nucleotides pair in a specific way.
example: C--G, A--T etc.

question

Plasmid:

answer

DNA molecule separate from the organism that can transfer information

examples: genes, antibiotic resistance

question

Sanger sequencing:

answer

Also known as DNA sequencing, Sanger developed rapid DNA sequencing because he discovered that nucleotides pair in a specific way.
example: C--G, A--T etc.

question

Franklin, Watson and Crick:

answer

Credited with discovering the structure of DNA.

question

Hershey and Chase are credited with:

answer

discovering that DNA is the basis for heredity.

question

Avery, McCleod and McCarty:

answer

Said that DNA is the transforming principle. The transforming principle was first described in Griffith's work. But Avery, McCleod and McCarty expanded on this and concluding that DNA was what altered the genetics of known bacterial strains.

question

Griffith's experiment:

answer

Used two strains of bacteria and infected rats with it. When the two strains were added to each other their virulence was altered.

This was the beginning of discovering that DNA was transformed and was the transforming principle.

question

Explain Hershey and Chase's experiment:

answer

1. Mix radioactive phages with bacteria. The phages will then infect the bacteria.
2. Agitate in a blender to separate phages outside the bacteria from the cells and their contents.
3. Centrifuge the mixture so bacteria collect at the bottom of the tube.
4. Measure remaining radioactivity.

-This proved DNA was the transforming principle.

question

The central dogma:

answer

DNA is transcribed by RNA via RNA polymerase. RNA translates RNA code into protein via ribosomes.

question

How are bacteria identified in general? What kind of tests could we do?

answer

-metabolism
-shape
-arrangement
-staining
-serology

question

What is serology?

answer

Serology is the study of blood serum and other bodily fluids. Usually refers to antibodies in the blood created in response to infection.

question

What is a bacteriostatic agent?

answer

Something that inhibits but doesn't necessarily kill bacteria.

question

Bioterrorism:

answer

know that post 9/11, the US postal service began irradiating the mail with high voltage electron beams used to kill bacteria after bacillus antracis was found in mail.

question

How do microbicidal agents work?

answer

-disrupt cell wall or membrane
-prevent synthesis of nucleic acids
-alter the function of cellular proteins

question

Microbial death rates when Microbicides are used:

answer

-constant % of cells die over time
-not all killed simultaneously
-calculating the microbial death rates helps us to tell how long sterilization is required

question

Methods of microbial control:

answer

Heat: moist or dry
Radiation: high energy waves can enter bacterial cells and damage them
Filtration: removes microbes from air and liquid
Chemical: antimicrobials such as halogens, alcohols or detergents are used.

question

Using heat as microbial control:

answer

Generally, the higher the temperature the more likely the effect is microbicidal. The lower the temperature the more likely it is microbistatic.

question

How are steam and pressure used for microbial control?

answer

when high pressure and high temperature are both used, it will kill endospores.
This is also known as autoclaving.

question

How are refrigeration and freezing used for microbial control?

answer

refrigeration and freezing act as microbistatics.
the main exception to this is the bacteria listeria. It can survive and reproduce in a refrigerated environment.

question

How is radiation used to control microbial growth?

answer

Ionization can disrupt DNA and interfere with protein synthesis.
UV radiation will lead to formation of abnormal bonds (thymine dimers).

question

Gram staining:

answer

Gram +: Thick peptidoglycan. Stains purple with crystal violet.
Gram -: Thin peptidoglycan. Stains pink with safranin.

*older cells wont stain correctly.

question

Acid fast staining (Ziehl-Neelsen):

answer

Mainly used for myobacterium tumerculosis. This bacteria has a waxy outer membrane composed of mycolic acid which allows for acid fast staining. Methylene blue is used as a counterstain, so acid-fast bacilli stain bright red in contrast.

question

What is LCMV? Recall from clinical correlates.

answer

Lymphocytic choriomeningitis virus.
-rodent born (house mouse)
-virus is found in rodent's saliva, urine and feces.

question

Bdellovibrio:

answer

Gram - bacteria which enters other Gram - cells in a parasitic fashion using enzymes and a drilling motion.
Has a virus-like lifecycle
-many cells from one infection. Does not host machinery.

question

S layer (or Surface layer):

answer

-Layer of protein on the cell surface
-found in bacteria and archaea
-ancient cell wall structure for stability
-attachment
-virulence: prevents immune recognition and attachment to host

*used in nanotechnology: filtration/circuits

question

3 domains of life:

answer

Bacteria, Eukarya and Archaea

question

Azidothymidine (AZT/ZDT), an antiretroviral:

answer

Thymidine analog (N3 at 3')

-works as a transcriptase inhibitor
-this terminates viral replication.

question

Translation and transcription occur at the same time in what type of organism?

answer

prokaryotes

question

DNA transcription:

answer

photocopies DNA in the form of RNA.

question

The genetic code is:

answer

redundant and universal. this helps the organism to anticipate for transcription or translation mistakes.

ex:
UUU, UUC =Phen.
UUA, UUG =Leu.

question

DNA translation:

answer

1. codon recognition
2. peptide bond formation
3. translocation

question

tRNA:

answer

2 languages coming together and being translated. Nucleic acids combine to form amino acids. amino acids combine to form proteins.

question

Mutations:

answer

Are a heritable change in the DNA sequence. Not all mutations change proteins. This is because there is redundancy built into the genetic code.

question

Horizontal DNA transfer: Transduction

answer

Genes can be shared and transferred between organisms. This could help bacteria to encode resistance to certain drugs.

question

Gene regulation:

answer

the process by which information from a gene is used in the synthesis of a functional gene product.

question

How do we control microbes in the environment?

answer

Historically:
-drying foods
-salting, smoking, pickling
-osmotic control (sugars, salts)
-boiling
-burning

question

Equine salmonella outbreak:

answer

-acquired from the hospital (nosocomial)
-after disinfection, salmonella was not found.
--then 2 more cases...

question

Sometimes microbes are _______ removed from materials but not killed or inhibited.

answer

mechanically

question

What is the difference between a -cidal agent and a -static agent?

answer

cidal: kill microbes by damaging the cell

static: temporarily inhibit reproduction of microbes

question

Variable resistance of microbes:

answer

Highest resistance:
-bacterial endospores
-prions

Moderate resistance:
-protozoan cysts
-naked virus
-staph. aureus

Least resistance:
-bac. vegetative cells
-fungal spores
-enveloped virus
-yeast
-protozoan trophozoites

question

Decontamination:

answer

the mechanical removal of most microbes

question

Sterilization:

answer

Complete removal or destruction of all viable microorganisms. Used on inanimate objects.

*works on everything except prions.

question

Disinfection:

answer

The distruction or removal of vegetative pathogens but not bacterial endospores. Usually used only on inanimate objects.

examples include: UV light, heat, alcohol, bleach.
**does not guarantee all pathogens are eliminated.

question

Methods of microbial control:

answer

-sterilization
-disinfection
-antisepsis
-decontamination

question

Main reasons for microbial control:

answer

limit spread of disease. limit food spoilage.

question

1980's canine parvovirus epidemic

answer

-entire litters of puppies died within 24 hours
-humane society and shelters had to close
-bleach was effective but it didn't always work.
--bleach is inactivated by organic matter and the virus was surviving because of this.

question

Pasteurization:

answer

Use of heat to kill pathogens and reduce spoilage in food and beverages.
-Historically: 30 min @63C
-Flash pasteurization: 15 seconds @ 72C
-UHT pasteurization: 1 sec @134C

question

Why is it important to know if an infection is viral or bacterial?

answer

bacteria can be treated with antibiotics. Viruses cannot.

question

Biofilm:

answer

aggregates of microorganisms.
-2/3 of human infections are caused by biofilms which end up in IV fluids and other hospital equipment due to use of improper sterile technique.

question

Fimbriae:

answer

-involved in attachment and immune recognition
-uropathogenic (e.coli uses fimbriae to adhere to the urinary tract)
-primary mechanism for virulence of e.coli and staph bacteria.

question

Spirochetes:

answer

a corkscrew shaped bacteria.
-motile via axial filaments which are non-immunogenic
-it's corkscrew motion imbeds pathogens into the tissues
-cause diseases such as syphilis, bejel, pinta and yaws.

question

conjugation (aka cell sex):

answer

involves partial transfer of DNA from one cell to another.

question

Chemotaxis:

answer

bacterial movement
-positive chemotaxis --> movement toward a nutrient
-negative chemotaxis --> movement away from a nutrient

question

flagella:

answer

confirs motility to an organism. the number of flagella help in identification.

question

Can you vaccinate after infection has occurred?

answer

In some cases, like with rabies, the virus is slow to grow. If you are vaccinated within 5-7 days, your body will become immune.

question

What is a neoplasm?

answer

an abnormal mass of tissue

question

These two anatomical regions of the cell may be bacteria incorporated into the cell, as proposed by endosymbiotic theory:

answer

-chloroplasts
-mitochondira

question

Are microbes typically positive or negatively charged?

answer

most microbes are negatively charged and they will move toward positively charged nutrient sources (via chemotaxis).

question

How are bacteria quantified in samples?

answer

# of cfu/volume

*cfu=colony forming units

question

What is a genome?

answer

The genome is the total content of DNA. The blueprint for life.

question

What is a nosocomial infection?

answer

An infection acquired from the hospital.

question

How does temperature affect bacteria?

answer

Temperature alters the shape of enzymes and lipids. Therefore the working enzymes and lipids that are constituent to a bacteria must operate at a specific temperature.

question

Microaerophiles

answer

require low oxygen levels to survive

question

aerotolerant aerobes:

answer

can use oxygen, but it is not essential.

question

faculative anaerobic organisms:

answer

can use respiration (oxygen) but can also switch to fermentation.

question

Aerobes:

answer

use oxygen

question

Anaerobes:

answer

use of oxygen is toxic

question

Hydrogen peroxide is broken down by what enzyme?

answer

Catalase. 2H2O2 --> 2H2O + O2

question

Superoxide dismutase destroys:

answer

superoxide radicals. 2O2- + 2H+ --> H2O2 + O2

question

In ________ different electron acceptors are used in the absence of oxygen.

answer

fermentation

question

This disease was first described by John Snow. It affects cell channels and transport (diffusion) systems causing dehydration.

answer

cholera.

question

These groups of bacteria are clonal and when plates are grown, massive evolution can occur.

answer

colonies

question

Pathogenesis is:

answer

the manner in which an organism can spread disease.

question

How can you tell if a bacteria is using the sugar in a medium?

answer

-it produces acid via fermentation
-it changes in pH (see above)
-might also produce gas

question

What is the transforming principle?

answer

DNA. Bacterial DNA was separated into virulent and non-virulent. When they mixed together, the non-virulent became virulent again. This was because the genes of the cells intermingled.

question

Describe the life cycle of bacteriophages:

answer

1. phage attaches to bacterial cell
2. phage injects DNA
3. phage DNA directs host cell to make more phage DNA and protein parts. New phages then assemble.
4. Cell lyses and releases new phages

question

bacteriophage:

answer

a virus that infects bacteria

question

How does flagellar movement differ in eukaryotes and prokaryotes?

answer

eukaryotes: whip-like
prokaryotes: rotating movement

question

Many cells have glycocalyx. How does this put them at risk?

answer

Viruses also have glycocalyx with which they can bind with normal glycocalyx. This allows for viruses to bind and invade bacteria.

question

The outer surface of many cells has a sugar coating composed of polysaccharides bound to proteins. This structure is ________, it functions as a receptor site.

answer

glycocalyx

question

Another name for a cell wall constructed of repeating subunits of NAG and NAMs. This cell wall is affected by Beta-lactam drugs that block NAM cross linking in growing cells.

answer

peptidoglycan

question

This man identified the antibiotic penicillin which produces the "zone of inhibition."

answer

Alexander Fleming

question

Treponema pallidum causes this disease:

answer

syphilis

question

Paul Ehrlich first described a "magic bullet." What did he mean by this?

answer

Antimicrobials. These were first identified when Ehrlich used stains to identify disease causing cells and then later when he was able to kill the disease without killing the person.

question

What is an attenuated vaccine?

answer

A vaccine that has elements of disease causing agent which are reduced in virulence. some examples include:
-pasteurella multocida
-chicken cholera
-anthrax
-rabies

question

What is Edward Jenner known for realizing?

answer

Jenner realized that people who worked with dairy very rarely contracted smallpox. This is because these people were exposed to cowpox (which is less virulent than smallpox).
Jenner then vaccinated 8 year old James Phipps (he hadn't been previously exposed to either smallpox or cowpox).

question

SOAP stands for:

answer

subjective, objective, assessment, plan

question

Helicobacter pylori infects:

answer

the lower part of the stomach and causes inflammation in the gastric mucosa. (ulcers)

question

Barry Marshall first described this bacteria which is Gram -, helical and causes ulcers because it produces urease which alters local pH and causes it to become more alkaline.

answer

helicobacter pylori

question

About 50% of people have helicobacter pylori colonies in their stomachs, only __% will get ulcer disease.

answer

10-15%

*a very small percentage will also get stomach cancer.

question

Describe the purpose of electron transport:

answer

molecules carry electrons across the membranes of mitochondria creating a hydrogen gradient which produces energy.

question

The most common infection in women ages 20-30. Causes an increase in pH in the vagina. This increases risk of STDs and PID.

answer

Bacterial vaginosis

question

What 2 bacteria can alter the flora in an environment?

answer

-clostridium
-bacterial vaginosis

question

What are the major groups of microbes?

answer

-bacteria
-algae
-protozoa
-helminths
-fungi

question

How are microorganisms isolated?

answer

most does not grow on artificial media. must purify from a complex sample. isolation of causative agent is difficult.

question

Chemotherapy:

answer

Development and use of drugs to treat infectious diseases.

question

What is serology?

answer

the study of antibodies in blood serum to test for infection.

question

Why was pasteurization originally invented?

answer

to treat wine.

question

Pasteurization:

answer

fast, low heat which kills organisms but retains flavor.

question

Describe cell theory:

answer

all living things are composed of cells. All cells come from other cells.

question

Robert Hooke discovered:

answer

cells

question

Archaea lack this feature of the cell wall:

answer

peptidoglycan

question

a good pathogen:

answer

spreads well

question

These "true nucleus" cells have organelles and are compartmentalized.

answer

Eukaryotes

question

This microbe is comprised of protein and nucleic acid. It requires a host.

answer

A virus

question

This type of motility is often seen in food poisoning with such microbes as listeria monocytogenes.

answer

actin based motility

question

This microbe grows at relatively low temperatures (allowing it to grow and multiply in refrigerators). It also disproportionately affects pregnant women.

answer

Listeria Monocytogenes

question

What is the name of the bacteria that causes flesh eating bacteria?

answer

Strep. Pyogenes. It causes necrotizing fasciitis. Scarlet fever is also a complication of strep. pyogenes.

* Gram + cocci, it grows in chains recovered from surgical sites.

question

Whooping cough is caused by:

answer

Bordetella Pertussis

question

How does bordetella pertussis make people sick?

answer

Whooping cough kills cillia and they are unable to move in their usual whip-like fashion.

question

This disease causes lipid accumulation in brain cells because lysosomes and peroxisomes are not functioning properly.

answer

Tay-Sachs

question

This type of agar is both selective and differential. It is selective in the sense that it contains crystal violet which kills Gram + bacteria and it will also host a variety of gram negative bacteria.

answer

MacConkey agar

question

What are Koch's postulates?

answer

1. Causative agent is found in every case of disease which is not in healthy hosts.
2. Agent must be isolated outside of the host.
3. When re-introduced it must cause the same disease.
4. Same agent must be re-isolated from the infected host.

question

Pathogenesis is described as:

answer

the mechanism by which a disease is caused

question

Bacteria and archaea are considered:

answer

prokaryotes

question

What component made wine good? What made it go bad?

answer

good wine had yeast
bad wine had abundant bacteria

question

This bacteria stains red on an acid-fast test:

answer

tuberculosis (tubercle bacillus)

question

This early epidemiologist, tracked cholera in London. He was also an anesthesiologist and the nature of gases helped him to understand how cholera spread through the population.

answer

John Snow.

question

Why and how would e.coli act as an indicator organism?

answer

Poop shouldn't be in the water. If e. coli is present, other more dangerous organisms could also be present.

question

Hospital hygiene and control of nosocomial infections is known as:

answer

infection control

question

What is etiology?

answer

the study of the cause of diseases

question

What is epidemiology?

answer

frequency, distribution and spread of diseases

question

This deltaproteobacteria is Gram - and forms a community of reproductive structures when food is limited. It's survival structure is called a myxospore.

answer

Myxobacteria

question

-stains lysosomes red
-used as a general stain and as a counter stain
-added to growth media for bacteria and cell cultures
-acts as a pH indicator changing from red to yellow between pH 6.8-8.0

answer

neutral red

question

What does each letter stand for in the DAMN NIT classification of disease?

answer

Degenerative
Anomaly
Metabolic
Nutritional
Neoplastic
Inflammatory/Infectious
Traumatic/Toxic

question

Eukaryotes with both filamentous and cellular forms.

answer

Fungi

question

A drug is:

answer

A chemical that alters physiology in any manner.

question

Drugs that act against diseases and drugs that are used for treating infections are known as:

answer

chemotherapeutic agents

question

A substance produced by natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms.

answer

Antibiotic

question

In the 1900's, 1/3rd of all children died of infectious diseases before the age of 5. Ehrlich termed the use of the word chemotherapy and popularized the concept of the magic bullet. This is the history that led to the discovery of:

answer

antibiotics

question

Semi-synthetic antimicrobials:

answer

These antimicrobials are made by altering the chemical structure of antibiotics. They are often more effective and lost longer and also usually easier to administer.

question

Synthetic antimicrobials

answer

antimicrobials that are completely synthesized in the lab.

question

What is the Kirby-Bauer method?

answer

It is a test in which antibiotic-impregnated wafers are inserted into cultures of bacteria to test which bacteria are susceptible to which antibiotics.

question

Why is it important to distinguish the stages of infectious diseases?

answer

All diseases move through the phases differently and therefore we can differentiate which disease an individual may have based on when and how the signs present themselves.

question

Stages/phases of disease:

answer

1. incubation (no signs)
2. prodromal (vague)
3. illness (severe)
4. decline
5. convalescence (no signs)

question

What is a reservoir?

answer

a site where pathogens are maintained as a source of infection. (ex: animal, human or non-living)

question

Zoonoses

answer

diseases that are naturally spread from animal to host to humans.
via --> meat eating, blood sucking arthropod vectors.
*Usually humans are the dead end.

question

Human Carriers:

answer

Are infected asymptomatic individuals who can infect others. Some will eventually become ill. One major example is Typhoid Mary.

question

How is disease transmitted?

answer

via vector, reservoir or portal of exit (fecal-oral). fomites: objects that carry infection transiently (ex: towel, toothbrush)

question

What is a nonliving reservoir?

answer

a reservoir that is in the soil, water or food.
-microorganisms often contaminate dirt or water by feces or urine.
*this is relevant because smallpox can survive in a nonliving reservoir.

question

What is epidemiology?

answer

The study of where and when a transmission occurs in populations. Epidemiology takes into account both incidence of new cases and prevalence (or number of cases).

question

Types of nosocomial infections:

answer

exogenous: acquired from health care environment
endogenous: pathogen arising from normal microbiota due to health care setting
latrogenic: via catheters, surgery

question

Non-specific defenses (immunology)

answer

1. skin, mucous membranes, chemicals
2. phagocytosis, complement, interferon, inflammation, fever

question

1st line of defense (skin):

answer

the skin is both a barrier with constant turnover and it also has a chemical component with salt, lysozyme and sebum (low pH).
It also has dendritic cells which participate in antigen presenting.

question

What are exotoxins?

answer

toxins secreted by an microorganism. Can cause major damage to host system.

question

What is the definition of an infection?

answer

Invasion of the host by a pathogen.

question

Describe the process of adhesion:

answer

Microorganisms attach to cells required to establish colonies.
-Adhesins: ligands typically found on fimbriae, flagella
-block to prevent infection

question

Toxoplasmosis:

answer

caused by toxoplasma gondii.
-apicomplexan protozoan
-oocysts are 10-13 micrometers
-it is an intracellular parasite

question

What is hemozoin?

answer

a pigment produced by plasmodium from digested host's hemoglobin. This pigment is used to identify malaria in RBC's.

question

What are the major complications of malaria?

answer

-neurological damage (cerebral malaria)
-headache, psychotic convulsions, coma, fever of over 108F
-pulmonary edema
-algid malaria (systemic shock)
-blackwater fever (as evidenced in the urine)

question

Diagnosis and Treatment of malaria:

answer

-based on the clinical signs
-parasite found in peripheral blood smear
-stain/fluorescent dye

question

Malaria is transmitted by:

answer

the bite of an infected anopheles mosquito

question

What is the relapse period for malaria?

answer

-could happen weeks, months or years later
-p. vivax & p. ovale reoccur due to dormant hypnozoites in liver cells.

question

Anemia period of malaria:

answer

Massive destruction of RBC's, varies by species of malaria but p. falciparum is the most severe.

question

Inflammatory response period of malaria:

answer

malaise, muscle pain, headache, loss of appetite, chills, teeth shatter, bed shakes, fever, copious persperation (104-106F), recovery phase (weak, exhausted)

question

What is the pathogenesis of malaria?

answer

1. inflammatory response
2. anemia
3. relapse

question

What is the incubation period of malaria?

answer

between 10 and 4 weeks (~2 weeks)

question

P. Knowlesi

answer

Rare form of malaria often mistaken for P. Malariae
-More common and severe
-fever every 24 hours
-common in SE Asia
-Reservoir: Macaques

question

P. Ovale

answer

A very rare strain of malaria also known as "mild tertian malaria."
-found in the tropics, W. Africa, India, Vietnam, Philippines
-Fevers every 48 hours

question

P. Malariae

answer

"Quartan Malaria"
-Found in Africa, India, Europe, Brazil, Panama
-Seen in chimps
-~7% malaria cases
-less parasitemia
-fevers every 72 hours

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P. Falciparum

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"Malignant tertian"
-most virulent
-50% of cases
-tropics/subtropics
-increased parasitemia
-fevers every 36-48 hours

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P. Vivax:

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"Benign tertian malaria"
-found mostly in Asia
-43% of cases
-early onset fevers, every 48 hours.

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Malaria is part of a group of parasites called:

answer

apicomplexa

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What are the routes of parasitic infection?

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-eyes
-respiratory tract
-skin
-sex
-vector borne
-fecal/oral

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Why could Westernization increase incidence of parasitic disease?

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for example, when westernized societies construct artificial damns on rivers they become stagnant which increases the risk for parasites.

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List two major concerns associated with parasites in general:

answer

1. They cause the most common opportunistic infections in AIDS patients.
2. They cause lyme disease (which is transmitted by ticks)

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What are some important facts about humans and parasites?

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1. Humans can be infected with more than 100 parasites. These include flagellates, amoebas, ciliates, worms and lice.
2. Some parasites host other parasites (hyperparasitism)

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On parasitic diseases:

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There are more parasitic than non-parasitic organisms that can cause disease. Organisms that are not parasites usually host the parasite.

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What are some exceptions to Koch's postulates?

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1. Some pathogens can't be cultured
2. Some diseases are combination and can be caused by multiple pathogens.
3. ethical problems

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What are Koch's postulates?

answer

1. Isolate
2. purify culture
3. must cause the same disease
4. purify the culture again

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What is germ theory?

answer

The theory that a disease is caused by infections of pathogenic organisms.

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What does the term etiology mean?

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Etiology is the study of disease

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What is a syndrome?

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A group of symptoms and signs that characterize a disease or abnormal condition.

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What is a "sign," in terms of diagnosis?

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An objective manifestation of disease that can be observed or measured by others.
example: elevated blood pressure.

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What is a "symptom," in terms of diagnosis?

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A subjective characteristic of disease felt only by the patient.
example: itchiness, pain, malaise etc.

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When an invading pathogen alters normal functions of the body. That person would be said to be suffering from a:

answer

disease.

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What are some examples of specific immunity?

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antigens such as epitope target a specific area or shape. hapten is a small molecule not recognized but can be complexed. for example: penicillin.

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What does Gamma interferon do?

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Stimulate phagocytic activity of macrophages and neutrophils.

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Describe the interferon system:

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Infected cells release interferon. This is then sensed by adjacent cells. This shuts down protein synthesis temporarily.

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What are the lymphocytes involved in specific defense?

answer

B cells, T cells and NK cells

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How do antibodies work?

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Antibodies are shaped like a T and thus have 2 binding sites on each end. Antigens then bind to each end facilitating agglutination.
In opsonization cells are marked so that antibody cells know to phagocytize them.

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What does the antibody IgG do?

answer

comprises 85% of serum antibody. Can cross the placenta and enter the tissues.

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What does IgM do?

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It is the primary response to antigens. It has a structure that is extremely efficient at agglutination.

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How are chicken pox and shingles related?

answer

Chicken pox can cause shingles and vice versa. varicella-zoster virus.

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Symbiosis:

answer

2 organisms living together.

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Mutual commensalism:

answer

one organism benefits while the other is not affected.

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Parasitism:

answer

one organism benefits while the other is harmed.

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What are resident microbiota?

answer

Part of the normal microbiota throughout life. Most are commensal.

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Transient microbiota:

answer

Remain only hours or months. Cannot persist in the body due to competition, defenses, chemical or physical changes.

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How do opportunistic pathogens work?

answer

1. Normal microbiota can cause disease under certain circumstances
2. Conditions provide opportunity for pathogens.
-immune system suppressed
-intro into unusual site
-changes in normal microbiota

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How are microbiota acquired?

answer

-womb is microorganism free
-microbiota develop during the birthing process
-much of one's resident microbiota established in the first year.

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What do IgE's do?

answer

release histamine (allergic reaction)

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Contamination (pathogen entry)

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presence of microbes in the body. This is NOT an infection, rather, it simply describes that the microbes are there.

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IgA's are found in:

answer

milk, tears, GI and urinary tracts

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Infection results when:

answer

an organism has evaded the body's external defenses, multiplied and became established.

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Pathogenicity vs. virulence:

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the ability of the pathogen to produce infectious disease is the pathogenicity. virulence refers to the degree in which it is in the bloodstream.

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CD glycoprotein:

answer

specific glycoprotein used to distinguish cell types.
example: HIV targets CD4 T cells.

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Macrophages

answer

target invaders and are found throughout the body. Act as scavengers in the first line of defense in active defense and diapedesis.

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Mucous membranes as first line of defense:

answer

provide a minor barrier, high turnover, trap organisms with cilia which move invaders up and out. Lysozyme is also found in the nose and eyes.

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What is the agent, transmission, occurence, symptoms and treatment given for shigella?

answer

agent: shigella sonnei, flexneri or dysenteriae type 1
transmission: fecal oral, food borne
occurrence: 165 M cases, 1 M deaths
symptomps: watery, bloody diarrhea, abdominal pain, fever, vomiting
treatment: supportive antibiotics

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How does inflammation and fever influence our defenses?

answer

Inflammation and fever increase antibodies, increase phagocytosis and increase interferon activity.

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Eosinophils:

answer

elevated levels indicate parasitic infection and allergies. Eosinophils release toxins and RNAase to combat viral infection.

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Neutrophils:

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When elevated are an indication of bacterial infection. They are phagocytic.

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What is the epidemiology of toxoplasmosis?

answer

it is cosmopolitan in the human population. It causes complications in immuno-suppressed patients and pregnant women. It is found in feral and exotic cats as well as undercooked meat.

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Acute signs of toxoplasmosis:

answer

-swollen, painful lymph nodes
-fever, headache, muscle pain, anemia, dyspnea
-rarely causes death
-often mistaken for the flu

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sub acute signs of toxoplasmosis:

answer

extensive lesions in the lungs, liver, kidneys, heart, eyes and brain.

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Cell mediated immunity:

answer

defense against intracellular pathogens and abnormal host cells. Does not involve antibodies. (More in notes)

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Herd immunity:

answer

When a vaccination creates disease resistance among a population that is sufficient to limit spread of disease.

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Major histocompatibility complex (MHC):

answer

The basis of self recognition in organ transplant. MHC's hold antigens for presentation to T cells.

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T lymphocytes:

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cell mediated immune response. they have a unique t-cell receptor specific to the antigen.
-cytotoxic T's
-helper T's

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B lymphocytes:

answer

make antibodies. There are 300,00 identical receptors per B cell. Each receptor recognizes only one antigen.

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lymphatic system:

answer

immune cells are produced in the bone marrow. they then differentiate into b cells (marrow) or t cells (thymus). lymph nodes then collect cells and then spleen filters the blood.

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What is the body's second line of defense?

answer

-blood stem cells in bone marrow
-variety of other cells such as lymphocytes and antibodies.

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lymphocyte editing:

answer

B/T receptor shapes are randomly generated for self recognition.

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Detergents:

answer

Act as a germicide because they act as surfactants. They must be cationic to be most effective. (quaternary ammonium or "quats"). They work by disrupting the cell membranes.

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Alcohol as a germicide:

answer

Denatures proteins. Disrupts cytoplasmic membranes.
-70-90% used (full strength alcohol is not effective)
-20 minutes
-damages plastic, rubber

question

phenols as germicide:

answer

Denature proteins, disrupt cell membranes. Have low toxicity and are therefore less effective against spores.
*pseudomonas has been found in chlorhexadine.

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Halogens as germicide:

answer

highly effective disinfectant and antiseptic.
-betadine scrubs
-inactivates enzyme by oxidation

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aldehydes as germicide:

answer

-causes cross linking of membrane proteins
-disrupts enzyme function
-fast acting, high level disinfectant

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Ethylene oxide (gas sterilization) as germicide:

answer

-blocks DNA replication
-slow acting
-very explosive

question

hydrogen peroxide as a germicide:

answer

-relies on direct/indirect actions of oxygen.
-free radical formation is toxic.

question

What are some complications associated with chicken pox?

answer

shingles, secondary infections, invasive groupA strep disease, organ dissemination, pneumonia, reyes syndrome, congenital vericella syndrome.

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Heavy metals as germicide:

answer

arsenic, zinc, mercury, silver and copper. All of these elements combine with S atoms in cysteine molecules which results in an altered and non-functioning protein shape.

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Diagnosis and treatment of chickenpox:

answer

clinical, serological and supportive.
-or vaccine vZIG.

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chronic signs of toxoplasmosis:

answer

-host immunity builds up and suppresses tachyzoites
-tissue cysts lie dormant
--if ruptured cause intense hypersensitivity, inflammation
*chronic encephalitis, epilepsy, paralysis, retinal damage

question

congenital toxoplasmosis:

answer

-mother contracts while pregnant
-mostly in 3rd trimester
-causes mental retardation
-subclinical form can become active
*most common congenital abnormality in the US.

question

transmission of toxoplasmosis:

answer

-raw or undercooked meat containing cysts
-ingesting oocytes from cat feces/soil
-flies, cockroaches, earthworms

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sings and symptoms of chicken pox (vericella-zoster herpes virus):

answer

fever, malaise
macules --> papules --> vesicles --> postule --> crust

*shingles (15-20%)

question

Transmission of chickenpox:

answer

-10-28 day incubation
-respiratory or vesicle skin break
-infectious 1 day before rash and during symptoms
-highly infectious
--75% transmission rate

question

Pathogenesis of chickenpox:

answer

respiratory --> lymphatic --> skin, respiratory and nerves

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