MIC 205L Discussions

STUDY
PLAY
Define contamination
The action or state of making or being impure with unwanted/accidental introduction of microbes.
Why do you think the enriched media plate was incubated at 37 C?
Because the bacteria was collected on the human body, which is 37 C; so in order for that bacteria to keep growing, it needs to be kept at the same temperature as the body.
Hopefully you realize now that the microorganisms are in the air, dust, you, etc. What is one procedure that we follow at the beginning and end of each laboratory to cut down on the numbers of contaminating microbes?
Washing your hands and benches.
What are some ways that the numbers of microorganisms might be decreased in a hospital setting?
Changing the type of cleaner used to prevent unintentional selection of resistant bacteria, and making people wash their hands before entering into common areas, such as the food court.
What information should be included in labeling your lab work?
Name, date, specimen, section # (and type of plate or test if applicable).
Describe two example tragedies that could result from inadequately labeled lab work in a hospital.
You could grab the wrong plate and the plate could potentially be lost. Or you could not know what object/specimen that was swabbed/inoculated on that plate and you wouldn't be able to get any results from that plate.
Results and Conclusions are two different things in science. Results refer to the actual data that you collect, like the number of colonies we obtained after washing our hands a certain way. Our Conclusions are the logical judgement or analysis we make from our Results, like "This way of handwashing is more effective than that one." What Conclusions can you make from your experiment? Did your experiment support your hypothesis or refute it?
Hand sanitizer was more effective than hand washing with soap and water, which refutes our original hypothesis that using soap and water would be more effective.
Often when researchers perform an experiment the first time, they see ways that the protocol could be improved. Perhaps they discover another variable that they hadn't thought of and didn't control for. Maybe they obtained some unexpected results that give them an idea for another experiment. What are some ideas for improvements or further research you could suggest after your experiment?
The two students who used soap and water could try air drying their hands instead of using paper towels. We could further this research by trying other methods of drying hands (such as using a towel) to see which method is most effective.
In medical research double blind controls are often used. From your lecture, text or other source, define this term and explain why it is important.
Neither the subject or the researcher knows which subjects are receiving the active treatment, or the placebo. This is important because then the researchers as well as the subjects have no bias. By removing subjective bias, it creates a more controlled experiment.
List 5 possible sources of microorganisms that you have touched in the last hour.
Notebook, pen, laptop, lab manual, and a chair.
What is the difference between normal flora and transient flora? Describe an experiment to differentiate between resident species and transient species on your hands.
Normal flora are species of natural microorganisms that live on your body. Transient flora are microorganisms that are temporary and can be removed by hand washing. To test for transient flora, swab your hand before washing and inoculate half of a TSA plate. After washing your hands, wait for a while (make sure you keep your hands away from any sources of microorganisms while doing this) to let the normal flora replenish itself. Swab your hand again, and inoculate the second half of the plate. Incubate for 24 hours, then compare the two halves. If there are any flora that is on the first half but isn't on the second half, is transient flora.
Define nosocomial infection and describe how handwashing can help decrease the probability of these infections.
Nosocomial infections are infections that were acquired in the hospital (AKA the patient did not come into the hospital with this infection). Hand washing can decrease this because a lot of microbes inevitably collect on our hands because we use them for just about everything. So by washing your hands frequently, the potential infection-causing microbes can be removed/killed before spreading the microbes to another person (by shaking their hand for example).
The particular locations shown in Figure 2.1 usually contain the highest numbers of microorganisms. Why do you think that might be true?
Fingernails- because dirt and microbes get stuck under them and are not often cleaned out.
Under Jewelry- because it gets hot and moist (ideal growing conditions for bacteria) and doesn't often get cleaned under.
Between Fingers- because it gets hot and moist (ideal growing conditions for bacteria).
Wrist- because the wrist doesn't get cleaned as well or is neglected during hand washing.
What is the total magnification of the microscope when you are using the oil immersion lens?
10x (ocular) X 100x (objective) = 1000x
Simple microscope
A microscope with a single magnifying lens.
Compound microscope
A microscope with two magnifying lens: ocular and objective.
Parfocal
When one lens is in focus, all the others are as well.
Refraction
The fact or phenomenon of light, radio waves, etc., being deflected between one medium and another through a medium of varying density.
How often should you clean the lens of your microscope?
Before you use it, a couple times while you're using it, and after you use it.
If you had a letter "p" right side up on a slide, draw below how the letter would appear through the microscope.
d
Which objective lens should you use first for viewing a slide and why?
The scanning lens because you can see the widest range of the slide. Since the microscope lenses are parfocal, you can change the lens to the next/higher magnification lens and it will be focused, but with a smaller visual range. So you need to start off on the lens with the widest range so you can find the organism faster/easier.
Which is more important in the quality of the a microscope lens, it's magnification or its resolving power? Why?
The resolving power because that is what determines how close together we can see two objects. It's not magnification because if you magnify it beyond its resolving power, the result is an empty magnification, which is not useful.
Record the numerical apertures in Table 5.2 from each of the objective lenses on your microscope. The calculate the resolving power of each lens. Show your work. Use 0.5 micrometers (i.e., 500 nanometers) for the wavelength of light.
Scanning: 0.1
RP= 0.5nm/ (2 * 0.1) = 2.5mcm

Low Power: 0.25
RP= 0.5nm/ (2 * 0.25) = 1mcm

High Dry: 0.65
RP= 0.5nm/ (2 * 0.65) = 0.38mcm

Oil Immersion: 1.25
RP= 0.5nm/ (2 * 1.25) = 0.2mcm
Fluorescence
The ability of a substance to absorb invisible, dark, or ultraviolet light; and then emit light back as visible color of light.
Pseudopodia
A temporary cytoplasm-filled projection of a eukaryotic cell membrane or a unicellular protist.
Eukaryote
An organism consisting of cells where the genetic material is DNA in the form of chromosomes with a distinct nucleus.
Prokaryote
A microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles.
Vibrio cholerae is a vibrantly motile bacterium and is the etiologic agent for cholera. What type of microscope would be most useful in observing the motility of this microbe?
A darkfield microscope.
What type of microscope would be most helpful in studying the 3-D fine structure of the surface of microvilli from the intestine?
A scanning electron microscope.
Pure culture
A medium growing one, and only one, intended species of microorganism.
Transport medium
Is used to transport microbes from one place to another and supports survival without allowing overgrowth.
Sterile
Completely devoid of life.
Colony
A cluster of identical cells on the surface of a medium derived from a single parent cell.
Aerosol
A suspension or dispersion of fine particles (bacteria) in a gas.
Describe three medical procedures that demonstrate the two goals of aseptic technique. (e.g., When giving an injection, the needle should be sterile to avoid infecting the patient. After the injection, the needle should be disposed of properly to avoid transmitting a patient's disease to others.)
1) When handling surgery equipment/tools, the equipment and tools need to be sterile (as well as the doctor's hands/gloves) to avoid infecting the patient. After the tools are used they should be properly cleaned/disposed of.

2) When inserting a catheter, the catheter and the doctor's hands/gloves should be sterile to avoid infecting the patient. When it is removed the doctor's hands should be washed and the gloves and catheter should be properly disposed of to avoid infecting the patient or transmitting their disease.

3) When inserting an IV, the needle should be sterile to avoid infecting the patient and it should stay covered when it is in use. When it is removed, the needle should be properly disposed of to avoid transmission of the patient's disease to others.
Demonstrate your understanding of the term synthetic medium by briefly describing an experiment that would require this type of culture.
If you were trying to learn about what type of sugars a new microbe needed to survive, you would use a synthetic medium. You would make a couple different types of synthetic mediums, each one with a different type of sugar, in order to see which one(s) the microbe needs to survive.
In the transfer technique procedure why is it important to cool the loop before obtaining an inoculation of bacteria?
If the loop is too hot, it could burn and kill all of the bacteria and the transfer would not be successful, and it could cause aerosolization of the bacteria releasing it into the air where you could breathe it in and become infected.
Mannitol Salt Agar, MSA, is used for growing Staphylococcus. The high salt concentration in the medium inhibits the growth of most other genera. This medium is also useful because the pathogen, Staph. aureus, ferments mannitol and changes the agar from red to yellow, while the normal flora, Staph. epidermidis, does not change the color of the medium. Is MSA a differential medium or a selective medium or both or neither? Explain.
MSA is a selective and differential medium. It selects for members of the genus Staphylococcus since it can tolerate the high salt levels, while killing any other genera that can't. It is also a differential medium because it has a diagnostic test built into it in which the medium will change colors if a bacteria can ferment mannitol.
In the later part of the 19th century Robert Koch and his lab used Koch's Postulates to prove the causes of a variety of diseases plaguing mankind, including tuberculosis, gonorrhea, anthrax, strep infections, staph infections, cholera, diphtheria, etc. Koch himself originated the pour plate technique, while two people working in Koch's lab, Leoffler and Gaffky, developed the streak plate method. In the space below list Koch's postulates and put a star by the step(s) where these methods would be useful.
1) The microorganism must be present in all cases of the disease.

*2) The pathogen can be isolated from the disease host and grown in a culture.

3) The pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible individual.

*4) The pathogen must be isolated from the new host and be shown to be the same as the originally inoculated pathogen.
Koch's lab originally used gelatin to produce solid media. This is the same gelatin used in Jello. Later, another member or Koch's lab, Walther Hesse, got the idea from his wife to use agar. From your own experience with gelatin (Jello), list two advantages agar has over gelatin for microbiological media.
1) Agar melts at above body temperature, whereas gelatin melts below body temp., so growing bacteria at body temp. would be impossible on gelatin.

2) Gelatin can be digested by microbes, whereas agar cannot.
List one purpose for the streak plate and two for the pour plate technique.
Streak plate: to isolate colonies

Pour plate: to count bacteria by isolating colonies, and by creating a 'lawn' of bacteria
In the dilute pour plate for Micrococcus, what difference did you notice between colonies growing within the agar and those growing on the surface?
The colonies on the surface seemed larger and wider/more flat, while the colonies within the agar seemed smaller and more spherical in shape.
Why are all the Petri plates incubated upside down (i.e., agar side up)?
So the condensation on the lid doesn't fall into the agar and mess up the bacteria's growth.
Which species showed the fastest average generation time in our experiment?
Serratia marcescens
Was our experimental hypothesis supported? Why or why not?
No, because the bacteria that had the quickest generation time was S. marcescens and not E. coli.
What can be done by health care workers to decrease the chance of cystitis during catheterization?
They can insert the catheters using aseptic technique.
What does TNTC stand for?
Too Numerous To Count
Write 1/100,000 in powers of ten.
10^-5
Write 5,646,004 in scientific notation.
5.6 x 10^6
Using scientific notation calculate how many bacteria per milliliter there would be in the sample Figure 8.4. Show your work.
Number of CFU/( Volume plated (mL) * Total dilution plated)

36 CFU/(0.1mL * 10^-3) = 36 x 10^4 = 3.6 x 10^5 CFU/mL
Suppose a broth has 436 million bacteria per milliliter. A serial dilution is made using three bottles of 99 milliliters each. 1 mL is transferred from the sample to the first bottle; 1 mL is transferred from the first bottle to the second; and then 1 mL is transferred from the second bottle to the third. From the third bottle 0.1 mL is transferred to a pour plate. How many colonies would you expect to find on this plate?
Bottle 1: 10^-2
Bottle 2: 10^-4
Bottle 3: 10^-6
Pour plate: 10^-7

10^-7 mL * 436 million bacteria/mL
10^-7 * 4.36 x 10^8 = ~44 colonies
Clostridium perfringens causes gas gangrene and has a very rapid generation time of only nine minutes. Suppose a patient had a wound with a single Clostridium perfringens bacillus. How many C. perfringens bacteria would there be in the wound after just nine hours of multiplying. (Hint: since each generation time or doubling is 9 minutes long and there are 60 minutes in an hour, 9 hours would contain 60 divisions or doublings).
2^60 = 1.5 x 10^18 bacteria
Simple stain vs differential stain
A simple stain will stain all the cells the same color. A differential stain will dye different kinds or bacteria in contrasting colors.
bacillus vs Bacillus (italicized)
bacillus is a shape and Bacillus is a genus of bacteria.
Spirochete
A flexible helicoidal bacteria.
Sarcinae
Cubes of cocci.
Using the text or other references (Like this quizlet full of all the answers you're graciously using. You're welcome.), describe the morphological shape of the microorganisms that cause the following diseases in Table 9.2.
Syphilis - spirochete
Gonorrhea - diplococci
Lyme Disease - spirochete
Strep Throat - streptococcus
Vaginal Candidiasis - oval-shaped
Cholera - vibrios (comma-shaped)
Based on the information you learned today, how could a person diagnose the disease thrush, an oral yeast infection? (i.e., How could you differentiate it from a bacterial infection?)
Based on their size and shape, yeast is a Eukaryote, so it will be much larger in size compared to a bacterial infection.
Define mordant.
It causes a stain to become more tightly bound to the cell.
In a Gram stain if a person used too little alcohol or none and all, what color would a Gram-negative bacterium like Escherichia coli turn out? Why?
The crystal violet would stain the Gram-negative E. coli purple unless the alcohol was used because it rinses it off. If no alcohol is used, the Gram-negative would look like a Gram-positive because the purple color wasn't rinsed off.
What effect would an old culture have on the results of a Gram stain? Explain your answer in terms of the permeability theory.
The permeability states that as the cell ages, some cells begin to die and their cell walls break down. The broken down cell wall is no longer able to prevent the alcohol from leaching out the crystal violet.
Make a pair of detailed drawings showing the differences and similarities between Gram-positive and Gram-negative cell walls.
Gram Positive:
Outside the cell
------------------------
/\/\/\/\/\/\/\/\/\/\/\
/\/Peptidoglycan/\/\
/\/\/\/\/\/\/\/\/\/\/\
------------------------
Cell Membrane
------------------------
Inside of the cell

Gram Negative:
Outside of the cell
------------------------
Cell Membrane
------------------------
/\/Peptidoglycan/\/\
------------------------
Cell Membrane
Mark the appropriate column in Table 10.1, to indicate whether Gram-positive or Gram-negative correspond to each of the characteristics or diseases.
Sensitivity to Penicillin - Positive
Sensitivity to Lysozyme - Positive
Lipid A Endotoxin - Negative
Gonorrhea - Negative
Strep Throat - Positive
Cholera - Negative
Typhoid Fever - Negative
Tetanus - Positive
Diphtheria - Positive
How could you differentiate between bacterial pneumonia and viral pneumonia using the Gram stain?
Viruses cannot be seen with a Gram stain. So if you perform a Gram stain and could see the bacteria, it would be bacterial pneumonia; if you could not see anything, it would be viral pneumonia.
The "thermal death point" (TDP) is the lowest temperature required to kill all of a certain species of bacteria within a given amount of time (usually 10 minutes). Describe an experiment you could design to determine the TDP for Staphylococcus aureus.
Heat up a water bath to a temperature (30 C, 40 C, 50 C, etc.) and inoculate the bacteria at each temperature for 10 minutes. Look at your results to see which temperature was the TDP for S. aureus.
Differeniate between TDT and TDP.
TDT (Terminal Death Time) is the shortest time required to kill a suspension of cells or spores at a given temperature.

TDP (Terminal Death Point) is the lowest temperature to which an organism is killed in 10 minutes.
Why is pressure used in an autoclave?
The pressure increases the boiling temperature of water, so you can get hotter water which wil kill all microbes.
Was your hypothesis (from the Introduction) supported by your results? Why or why not?
We stated that S. epidermidis would be more resistant to UV light in our hypothesis, and our results supported this because more colonies grew after B. megaterium had stopped growing.
From your text, lecture, or your own experience list two medical examples of how ultraviolet light is used to control microorganisms.
Hospitals will use UV lamps to sterilize surgical equipment and the air in operating rooms. UV therapy is another use for UV light which uses UV light to treat skin conditions such as Psoriasis and eczema.
Define and diagram a thymine dimer.
In a DNA molecule, the pyrimidine bases (such as thymine) can absorb the UV energy and form an abnormal bond with an adjacent pyrimidine (i.e., thymine to thymine bond).

-------------
G A T=T A G
| | | | | |
C T A A T C
-------------

When the bonds occur between two thymine, it's called a thymine dimer.
When you receive your copy of the tabulated class results, use this space to ionterpret those results. Compare the effectiveness of the various disinfectants and compare the resistance of the two species of bacteria.
Lysol, Alcohol, Mouthwash, Bleach and 70% Alcohol were the best disinfectants, killing most bacteria in 30 seconds. Hydrogen Peroxide and Betadine were the least effective by still having growth at 3 minutes. In a majority of the results, E. coli died first meaning that B. megaterium was more resistant to the disinfectants.
List one virus and three genera of bacteria that are highly resistant troublesome forms.
HIV
Mycobacterium (M. tuberculosis)
Staphylococcus (S. aureus - MRSA)
Pseudomonas (Ps. aeruginosa)
Why is it important to clean fomites before disinfecting them?
Washing/cleaning will remove 90-95% of pathogens present. The disinfectant will remove the rest, but not all disinfectants kill all pathogens/bacteria. This is why it is best to clan away as many pathogens as you can first.
Disinfectant
Are chemical agents that kill vegetative, pathogenic microorganisms.
Sterilize
Destruction or removal of all organisms from an object or from a particular environment.
Iodophor
A complex iodine and a surfactant that releases free iodine in solution, used as antiseptic disinfectant.
Tincture of iodine
Is an antiseptic; usually 2-7% elemental iodine, along with potassium iodine or sodium iodine, dissolved in a mixture of ethanol and water.
Bactericidal
Kills bacteria (many possible mechanisms).
Fungistatic
Capable of inhibiting the growth of fungi without killing them.
Were there differences in the sensitivities of the two bacteria in this exercise? If yes, how can you explain these differences? If not, why not?
S. epidermidis is more sensitive than E. coli because whenever an antibiotic was not effective, it was the E. coli. This could be because S. epidermidis is Gram positive and E. coli is Gram negative.
Define PPNG.
Penicillinase-Producing Neisseria Gonorrhoeae is a strain of gonorrhea. These bacteria have become resistant to the antibiotic penicillin. These bacteria have to be treated with a different antibiotic.
Define MIC.
Minimum Inhibitory Concentration is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation.
Define superinfection.
A second infection superimposed on an earlier one, especially by a different microbial agent of exogenous or endogenous origin, that is resistant to the treatment being used against the first infection. It is an opportunist that will overgrow.
Besides bacterial sensitivity, what are some other factors a physician would need to consider before prescribing an antibiotic for a patient.
Some antibiotics are very toxic to select body systems, so a physician must be sure the patient can tolerate it. They also must be sure to not given the patient too many antibiotics or too much because the bacteria may grow resistance to them.
Penicillin did not reach the market for general use until 1943. However, when was the resistance to penicillin by Staphylococcus first reported?
1940
What year was methicillin introduced to treat penicillin resistant Staphylococcus?
1960
How long did it take before MRSA (Methicillin Resistant Staphylococcus aureus) was reported?
2 years
The most dangerous MRSA is now resistant to every antimicrobial drug drug except vancomycin. In recent years in the cases of VRSA ( Vancomycin Resistant Staphylococcus aureus) have been reported. Describe how the process of natural selection applies to the increase in VRSA.
The bacteria is only being exposed to one antibiotic (Vancomycin), so when the bacteria randomly gets a DNA mutation, it could make the bacteria survive better. This random mutation could become resistant to Vancomycin, so it will survive and produce more daughter cells that will also be resistant.
What recommendations would you use to prevent or at least postpone the development of VRSA?
By being prudent when using Vancomycin, and not using it if possible. Reporting Vancomycin resistance promptly and immediately implementing appropriate infection-control measures to prevent person-to-person transmission of the resistant bacteria.
Is blood agar an enriched medium or a differential medium? Explain.
It is enriched because it contains added nutrients to enhance the growth of particular bacteria, and it is differential because it can differentiate between Streptococcus based on the reaction produced.
Is mannitol salt agar differential or selective medium? Explain.
Selective because of the high salt concentration will favor the growth of some bacteria over others. It is differential because it will change colors if mannitol is fermented.
Do your results from the bile esculin agar and salt test support placing Enterococcus faecalis into group D? and into enterococci? Explain.
Both the bile esculin agar and salt test were positive, meaning it is in group D and is streptococci, not enterococci. Group D can only grow on the bile esculin agar, and only streptococcus can grow in the salt test.
Define coagulase.
Is an enzyme produced by S. aureus that will cause plasma to clot.
Name three potentially dangerous species of Streptococcus other than S. pyogenes and the diseases caused by them.
Streptococcus Viridans - infective endocarditis
Streptococcus pneumoniae - pneumonia
Enterococcus faecalis - nosocomial infections
Explain how dietary sucrose, Streptococcus mutans, and other bacteria work together to cause dental caries.
S. mutans ferments fructose to create lactic acid, if there's a lot of sucrose in the diet and plaque isn't removed regularly, the lactic acid can dissolve the calcium of the tooth creating cavities or caries, called dental caries.
Based on your results, what is your tendency to form caries?
No susceptibility, because the agar stayed mostly green, meaning I do not have the bacteria in my mouth that produce lactic acid.
or
Very susceptible, because the agar turned yellow/black/brown/had lots of growth, meaning I have a lot of the bacteria that produce lactic acid.
What other factors contribute to a person's resistance or susceptibility to tooth decay?
Calcium fluoride concentration in teeth, lysosome and IgA concentration in saliva, and volume of saliva produced.
Obligate anaerobe
Killed by the presence of oxygen. Carry on aerobic respiration using something other than O2, or they metabolize food through anaerobic fermentation.
Clostridium difficile
Obligate aerobe
Use oxygen as their electron acceptor and must have oxygen in order to live.
Neisseria subflava
Facultative anaerobe
Can survive with or without oxygen. When oxygen is not present, they use anaerobic fermentation; when oxygen is present, they use aerobic respiration and obtain more ATP.
Staphylococcus aureus
Microaerophile
Require oxygen, however they grow best when the oxygen concentration is lower than the normal concentration (20%). Likes small amounts of O2.
Micrococcus luteus
Capnophile
Require extra carbon dioxide in their environment.
Streptococcus lactis
Why do aerobic organisms need oxygen?
Oxygen is their final electron acceptor in energy metabolism.
Is candle jar anaerobic? Explain.
No, oxygen is still present, it's just in a lower concentration than normal.
What is the most abundant species of normal flora in the human colon?
Firmicutes, Bacteroides fragilis, Actinobacteria, and Proteobacteria.
List four species of pathogenic anaerobes and the diseases they cause.
Actinomyces - endocarditis
Bacteroides fragilis - peritonitis
Clostridium difficile - infectious colitis
Porphyromonas gingivalis - periodontal disease
Make a mark in Table 30.3 to indicate whether the following reactions are based on nitrogen (protein & amino acid) metabolism or carbohydrate (sugar) metabolism.
Durham Tubes - Carbohydrate
Urease Test - Nitrogen
Sulfide Production - Nitrogen
Indole Production - Nitrogen
Methyl Red Test - Carbohydrate
Voges-Proskauer Test - Carbohydrate
Why does Pseudomonas give negative reactions on all the fermentations?
Pseudomonas are aerobic, so they don't undergo fermentation.
Why must you have a pure culture for inoculation of sugar fermentation and other biochemical tests? What would happen if the culture were contaminated or mixed?
Because if it was contaminated with a bacteria that fermented sugar, when the intended bacteria does not, the result would be positive when it should be negative. You don't want contamination because it can give you incorrect results.
Define IMViC
Stands for Indole test, Methyl red test, Voges-Proskauer test, and Citrate utilization test. These tests will identify an organism in the coliform group.
Is MacConkey agar a differential medium, a selective medium, or both?
It is selective because it inhibits the growth of Gram positive bacteria, and it is differential because bacteria that are rapid lactose fermentors turn pink, whereas bacteria that are not rapid lactose fermenters produce colorless colonies.
What is the prevalence rate of infection at the end of our study in class? (assuming 24 students)
12/24 *100,000 =
50,000 people per 100,000 people
Which number individual was the source case?
Tip: there should be two answers
Is it possible to narrow down the source case to just one person in this outbreak? Why or why not?
No, because you are unable to tell if person __ or person __ infected the other one without more information on the individual.
Epidemic
When a disease is spreading rapidly in a particular population.
Pandemic
When a disease is spreading rapidly globally or over more than one continent.
Endemic
When a disease has a prevalence rate that is fairly stable at a location.
Sporadic
When a disease occurs infrequently and in scattered locations.
Table 33.3 above tracks the number of students who caught gonorrhea during a school year at a hypothetical college with a total enrollment of 10,000 students. What was the incidence rate for the gonorrhea for that year?
22/10,000 * 10,000=
22 students per 10,000 students
Assuming the patients were treated and cured within two weeks, what was the prevalence rate at the end of the school year?
0/10,000 * 10,000=
0 students per 10,000 students
Now suppose the above disease was HIV and once infected, the person remained positive for life. Using the same table of data, now what would be the prevalence rate at the end of the school year?
22/10,000 * 10,000=
22 students per 10,000 students
The CDC estimates that about 12 million people in the U.S. develop an STD each year, and that at least half of all the people in the U.S. will develop an STD at some time before they are 35 years old. The group with the highest incidence rate is adolescents and young adults. What factors do you think make this population more vulnerable to STD's?
Young adults are sexually active and tend to not use protection, spreading their disease, and then they don't get tested very often; and adolescents because they could have gotten it from their mother (like HIV).
Which of the parasites you observed were intracellular?
Plasmodium falcparum
Which of the helminths you observed is typically diagnosed using scotch tape?
Enterobius Vermicularis
What is the larval stage of Taenia solium called and what animal is this larva normally found in?
Cysticercus; found in pigs.
Cysticercosis is an infection found in the larval stage of Taenia as found in a pig host. How can people become infected with cysticercosis?
Eggs are accidentally ingested from contaminated water or vegetables.
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