Lab Test 2

Question 1

Vocab for Kirby-Bauer DIffusion for Antibiotic Effectiveness

Answer 1

ANTIBIOTICS - natural substances produced by microbes that destroy or slow the growth of bacteria

ANTIMICROBIAL AGENTS - synthetic substances developed in the laboratory that mimic the effects of antibiotics

PENICILLIN - bactericidal, narrow spectrum drug that targets primarily Gram-positive bacteria.

NARROW SPECTRUM ANTIBIOTICS - active against a select group of bacterial types and are used to treat specific infections when the causative organism is unknown

BACTERICIDAL - leads to cell death

NOVOBIOCIN - bacteriostatic, narrow-spectrum antibiotic that targets DNA gyrase in some Gram positive bacteria (attacks DNA replication)

BACTERIOSTATIC ANTIBIOTICS - cause an inhibition of growth rather than cell lysis and death

GENTAMICIN - narrow spectrum, bactericidal antibiotic that targets aerobic, Gram-negative bacteria and Gram-positive Staphylococcus. Gentamicin binds with bacterial ribosomes, cellular structures responsible for protein synthesis.

KIRBY-BAUER DIFFUSION TEST - commercially prepared filter paper disks that have been infused with a specified concentration of a particular antibiotic

ZONE OF INHIBITION - The diameter of this zone of inhibition is measured in millimeters and compared to a chart that links the size of the zone of inhibition to the dosage that is often administered to a patient. The diameter of the zone is dependent on the sensitivity of a microorganism to a particular antibiotic and the physical properties of the antibiotic itself

Question 2

Understand antibiotics vs. antimicrobial agents

Answer 2

ANTIBIOTICS - natural substances produced by microbes that destroy or slow the growth of bacteria
ANTIMICROBIAL AGENTS - synthetic substances developed in the laboratory that mimic the effects of antibiotics

Question 3

Source of antibiotics and how we obtain them

Answer 3

Many different organisms produce antibiotics; whether they are used in clinical settings depends on the toxicity and the effectiveness of each agent. The majority of antibiotics used clinically are derived from four main genera. These include two bacteria: Bacillus and Streptomyces, and two fungi: Penicillium and Cephalosporium. Science has continued to expand the search for effective agents.

Question 4

Penicillin

Answer 4

Penicillin is a bactericidal, narrow spectrum drug that targets primarily Gram-positive bacteria. Penicillin disrupts the formation of bacterial cell walls by inhibiting the formation of peptidoglycan cross-links, resulting in cell lysis and ultimately cell death.

Question 5

Novobiocin

Answer 5

Novobiocin is a bacteriostatic, narrow-spectrum antibiotic that targets DNA gyrase in some Gram positive bacteria. DNA gyrase is an enzyme necessary for the replication of DNA. Without DNA replication, bacterial cells cease to grow and divide.

Question 6

Gentamicin

Answer 6

Gentamicin is a narrow spectrum, bactericidal antibiotic that targets aerobic, Gram-negative bacteria and Gram-positive Staphylococcus. Gentamicin binds with bacterial ribosomes, cellular structures responsible for protein synthesis. See Figure 4. When ribosomes are bound with gentamicin they are no longer able to synthesize protein and the bacterial cell ceases to grow and dies. Gentamicin is synthesized by the Gram-positive bacteria, Micromonospora.

Question 7

Narrow Spectrum antibiotics

Answer 7

Narrow spectrum antibiotics are active against a select group of bacterial types and are used to treat specific infections when the causative organism is known. Penicillin is considered bactericidal since it leads to cell death. Penicillin is produced by the mold, Penicillium.

Question 8

Bactericidal vs. Bacteriostatic

Answer 8

BACTERICIDAL - leads to cell death
BACTERIOSTATIC antibiotics cause an inhibition of growth rather than cell lysis and death. Novobiocin is produced by the bacteria, Streptomyces.

Question 9

Understand Kirby-Bauer Diffusion Test

Answer 9

The most common method used in hospital laboratories to assess bacterial antibiotic resistance is the Kirby-Bauer Diffusion test. The Kirby-Bauer Diffusion test is performed using commercially prepared filter paper disks that have been infused with a specified concentration of a particular antibiotic. When placed on an agar containing newly plated bacteria, the antibiotic diffuses away from the disk into the agar, creating a concentration gradient that decreases logarithmically with the distance from the disk. As the bacteria grow, they will be inhibited in regions where the antibiotic concentration is above what the microorganism can handle. Areas where the antibiotic concentration is low will allow for bacterial growth; this growth will lead to the creation of a lawn across the plate, creating a zone around each disk.

Question 10

Zone of Inhibition

Answer 10

The diameter of this zone of inhibition is measured in millimeters and compared to a chart that links the size of the zone of inhibition to the dosage that is often administered to a patient. The diameter of the zone is dependent on the sensitivity of a microorganism to a particular antibiotic and the physical properties of the antibiotic itself. Some antibiotics are not as soluble as others and as such will have a different diffusion rate through the agar. Therefore, a very large zone of inhibition does not necessarily mean that the antibiotic is extremely effective. The effective size for a zone of inhibition is calculated through hundreds of assays on many different strains of bacterial isolates correlating this information with many other susceptibility tests. In this method, an organism may be categorized as resistant, susceptible, or intermediate to a panel of antimicrobial agents. An intermediate result is based on when the results can be influenced by other factors. For example, the zone of inhibition may indicate the possibility that an agent would be effective, but the site of infection and the ability of the antibiotic to reach this site is suspect, and may not fully reach inhibitory concentrations. Under this circumstance, it would be recommended that a different antibiotic be selected.

Question 11

Understand the Kirby-Bauer Diffusion experiment and results observed

Answer 11

CHECK HOL

Question 12

Vocab for Hand Washing and Normal Flora

Answer 12

NORMAL FLORA - bacteria which are found in or on the human body and that do not, under normal conditions, cause disease

RESIDENT FLORA - colonized and established at specific sites on the body for the most of the host’s life.

TRANSIENT FLORA - colonizing the skin are acquired by either direct or indirect contact.

DIRECT CONTACT - one individual touches another by shaking hands or other means of physical contact

INDIRECT CONTACT - an individual touching a contaminated surface, such as an elevator button

Question 13

Understand Normal flora and the benefit of these microbes

Answer 13

Normal flora are found throughout the body including the skin, and the respiratory and gastrointestinal (GI) tracts. One of the many benefits of normal flora is that it competes against other, potentially pathogenic (disease causing) bacteria, for both attachment sites and nutrients. For this reason, normal flora are considered an innate defense mechanism against pathogenic infection. There are many factors that determine the type and number of normal flora that exist in any one region of the body, including: the availability of receptor sites for attachment, the availability of nutrients, the pH of the host site, and the temperature of the host site.

Question 14

Resident flora vs. transient flora

Answer 14

RESIDENT FLORA - colonized and established at specific sites on the body for the most of the host’s life.

TRANSIENT FLORA - colonizing the skin are acquired by either direct or indirect contact.

Question 15

Direct contact

Answer 15

one individual touches another by shaking hands or other means of physical contact

Question 16

Indirect contact

Answer 16

an individual touching a contaminated surface, such as an elevator button

Question 17

Why hand washing is important

Answer 17

Transient flora can be removed from the skin through hand washing. Frequent hand washing is one of the most effective ways of both avoiding and spreading disease. Either soap and water or alcohol-based sanitizers are effective at controlling transient flora. The goal of hand washing is to remove, not kill, microbes.

Question 18

Proper Hand washing method

Answer 18

The proper method for washing hands is:

1. Wet hands with clean, running water.
2. Apply soap to wet hands.
3. Create lather by rubbing the soap between hands and scrub between fingers, under nails, and over the entire surface of hands.
4. Continue scrubbing for at least 20 seconds.
5. Rinse hands under clean running water.
6. Dry hands with a clean towel.

Question 19

Hand Washing and Normal Flora experiment and results

Answer 19

Go to HOL-Interactive

Question 20

Vocab for Microorganisms as Vectors of Disease

Answer 20

DISEASE - a disruption of the normal state of an animal or plant that impairs bodily structure or function

INFECTIOUS DISEASES - caused by microscopic agents called pathogens

PATHOGENS - Viruses, bacteria, parasites, and fungi are examples of pathogens

CONTAGIOUS DISEASES - Infectious diseases that result from the transmission of pathogens from person to person

DIRECT TRANSMISSION - pathogen is passed immediately from one person to another via direct contact, such as a hand shake or by kissing.

INDIRECT TRANSMISSION -
* The pathogen is transferred to a fomite, a non-moving object such as a door knob, tissue, or used needle.
* The pathogen becomes airborne via water droplets produced by coughing or sneezing.
* The pathogen is transported by a vector such as a living animal or insect.

INCIDENCE - measure of new disease cases for a given population size over a given time.

VACCINE - a substance that stimulates the immune system to produce antibodies;

ANTIBODIES - proteins that identify and neutralize pathogens and other foreign threats

KILLED VACCINE - contains microorganisms that have been destroyed (killed).

LIVE ATTENUATED VACCINES - contain agents that resemble pathogens that are often either a weakened form of the pathogen or some of its molecular components, such as toxic proteins.

Question 21

What is a disease and what accompanies it

Answer 21

A disease is defined as a disruption of the normal state of an animal or plant that impairs bodily structure or function. Diseases are often, but not always, accompanied by distinguishing signs and symptoms. The term “disease” encompasses all ailments and sicknesses that are not related to an accident or natural aging. Diseases can have short or long durations, lasting from hours to years. Examples of diseases include the common cold, cancer, and diabetes.

Question 22

Understand the different types of diseases

Answer 22

A disease is defined as a disruption of the normal state of an animal or plant that impairs bodily structure or function. Diseases are often, but not always, accompanied by distinguishing signs and symptoms. The term “disease” encompasses all ailments and sicknesses that are not related to an accident or natural aging. Diseases can have short or long durations, lasting from hours to years. Examples of diseases include the common cold, cancer, and diabetes.

Infectious diseases are caused by microscopic agents called pathogens. Viruses, bacteria, parasites, and fungi are examples of pathogens. See Figure 1 for an illustration of a virus. Infectious diseases that result from the transmission of pathogens from person to person are called contagious diseases.

Question 23

Direct vs. Indirect transmission

Answer 23

DIRECT TRANSMISSION - pathogen is passed immediately from one person to another via direct contact, such as a hand shake or by kissing.

INDIRECT TRANSMISSION -
* The pathogen is transferred to a fomite, a non-moving object such as a door knob, tissue, or used needle.
* The pathogen becomes airborne via water droplets produced by coughing or sneezing.
* The pathogen is transported by a vector such as a living animal or insect.

Question 24

Incidence

Answer 24

measure of new disease cases for a given population size over a given time

Question 25

Understand vaccines and the different types

Answer 25

A vaccine is a substance that stimulates the immune system to produce antibodies; proteins that identify and neutralize pathogens and other foreign threats. The body retains antibodies produced during the vaccination, resulting in improved defenses when presented with a true pathogen. Vaccines are composed of either killed or live attenuated microorganisms. A killed vaccine contains microorganisms that have been destroyed (killed). Live attenuated vaccines contain agents that resemble pathogens that are often either a weakened form of the pathogen or some of its molecular components, such as toxic proteins.

Question 26

Understand influenza and influenza vaccines

Answer 26

Public health concerns of infectious disease in the U.S. often focus on common contagions, such as influenzas and colds. Influenza, commonly called “the flu,” is caused by a number of viruses. The influenza viruses are divided into three major groups (A, B, and C) and further classified into subtypes and strains. Although influenza symptoms may be stomach-related, influenza is a respiratory disease and is not a stomach or intestinal disease. In an average year, approximately 20 percent of Americans acquire influenza, which in some cases leads to hospitalization or even death.

Influenza vaccines are available as either a killed vaccine delivered through a shot (see Figure 4) or as a live attenuated vaccine delivered in an intranasal flu-mist. Each year, the influenza vaccines (both killed and attenuated) contain three types of influenza viruses that have been identified through research as the most likely to cause influenza in a given season. However, having improved immunity against the three selected viruses does not guarantee that a person will not contract influenza, as other stains of the influenza virus may become prevalent in a given community. Influenza antibodies take a few weeks to develop after vaccination. Effectiveness of the vaccine varies among individuals (for example, an elderly person versus a young adult). Although acquiring a flu vaccine does not provide 100 percent protection against contracting influenza, it greatly lowers a person’s chance of catching the flu and is a primary form of preventing the spread of contagion throughout a community.

Question 27

Understand the experiment of microorganisms as vectors of disease and results

Answer 27

Go to HOL-INTERACTIVE

Question 28

Understand common colds and understand why antibiotics aren’t effective against them

Answer 28

The common cold, another type of upper respiratory infection, is a disease caused by more than 100 different types of viruses. Unfortunately, there are no current vaccines that help defend a body against viruses that cause the cold. Because the predominant pathogens that cause flus and colds are viruses, antibiotics designed to kill bacteria are ineffective and only serve to increase antibacterial resistance in the human population. When taken for viral infections, medications are only effective if taken within the first 24 hours of contracting the disease. In most cases of flu or cold, patients are advised to treat symptoms with pain relievers and fever reducers and allow the disease to “run its course.”

Question 29

Vocab of Food Safety

Answer 29

FOODBORNE ILLNESSES - obtained from consumption of food contaminated with microorganisms

NORMAL FLORA - is comprised of those microbes commonly present in or on an organism and are normally not harmful to the organism itself

ENDOTOXINS - toxin from the lysis of Gram-negative cell walls releasing Lipid A

EXOTOXINS - enzymes secreted from bacteria that are toxic to the human body

INTOXICATION - ingestion of these toxins and can result in foodborne diseases.

CROSS CONTAMINATION - is the transfer of bacteria from one food item to another

Question 30

Understand foodborne illnesses

Answer 30

The Centers for Disease Control and Prevention (CDC) estimates one in six Americans become ill from foodborne pathogens, 3000 of these individuals die from foodborne diseases each year. See Figure 1. Foodborne illnesses are obtained from consumption of food contaminated with microorganisms. Foodborne illnesses present a significant public health risk. Preventing the transmission of foodborne illness involves committed awareness on all levels of food processing and preparation, including those steps taken in individuals’ homes

Question 31

Be familiar with the common microbes involved in foodborne illnesses

Answer 31

Most steps involved in food handling can result in possible exposure to a foodborne illness. Clostridium botulinum is a soil-dwelling organism commonly associated with poor food handling and processing procedures. The spores of C. botulinum can infect individuals consuming homecanned root vegetables such as carrots and potatoes. Other examples of foodborne illness caused by microbes include: Escherichia coli and Listeria monocytogenes infections resulting from consuming raw vegetables irrigated with contaminated water. In addition, Salmonella infections may result from improper handling of raw poultry.

Question 32

Understand how food becomes compromised

Answer 32

Prevention of foodborne illnesses is challenging because fresh foods are rarely grown in sterile conditions. Produce is exposed to microbes in the soil and from irrigation water. See Figure 2. When the exposed produce is not cleaned properly before consumption, foodborne illness in humans can occur. The butchering and processing of animal tissues may result in contamination with microbes that are found in the digestive system of the animal. Even though these microbes may not be harmful to the host animal, they may lead to foodborne illness in humans.

Question 33

Understand how to prevent foodborne illnesses in your home

Answer 33

Numerous precautions can be taken in one’s home to reduce the incidence of foodborne illness. Proper hand washing before handling food is important, as is washing one’s hands between handling different foods during preparation. To reduce the presence of microbes, fruits and vegetables should be washed with soap and water prior to being consumed raw.

Cross contamination, which is the transfer of bacteria from one food item to another, can be reduced by using different utensils and preparation surfaces for meats and produce. Finally, the proper usage of temperature, both hot and cold, can significantly reduce exposure to foodborne
pathogens. Colder temperatures reduce the reproductive rate of most microbes. Cooking meat to an internal temperature of 160°F (71°C) kills most microorganisms. Discarding food that has been unrefrigerated for a prolonged period of time also reduces foodborne illnesses.

Question 34

Understand cross contamination

Answer 34

Cross contamination, which is the transfer of bacteria from one food item to another, can be reduced by using different utensils and preparation surfaces for meats and produce.

Question 35

Understand experiments and the results observed

Answer 35

Go to HOL-INTERACTIVE

Question 36

Food safety progress report

Answer 36

Shows you which ones have increased and how many get it on average

Question 37

Vocab of environmental influences of microbial growth

Answer 37

OSMOLARITY - the concentration of solutes within a solution.

HYPERTONIC - solution with high osmolarity (hypertonic), such as a very salty solution, water from within the cytoplasm will move out of the cell. With the loss of water the stability of the cell membrane and other structures is reduced and the cell will shrink (crenate) eventually leading to cell death

HYPOTONIC - Conversely, if a microorganism is placed in a solution with low osmolarity (hypotonic), such as distilled water, water will move into the bacterium. See Figure 2. If the cell wall is unable to mediate the influx of water, the cell will burst.

ISOTONIC - Equal

HALOTOLERANT - microbes are able to survive at high salt concentrations but do not require these conditions for growth

HALOPHILES - they require a high salt concentration for growth

Question 38

Understand microbe environments and the environmental factors influencing their surivival

Answer 38

There are 10 million species of microbes on Earth living in diverse habitats. Microbes exist in fresh and salt water, above and below ground, and on and within other organisms. Microbes even thrive in extreme environments such as glaciers, hydrothermal vents, alkali pools, and even inside nuclear reactors. This diversity of habitats demonstrates the adaptability of microbes.

Numerous factors such as temperature, oxygen availability and pH influence where microbes are found in the environment. Temperature limits the distribution of many organisms. Enzymes, catalysts for metabolic reactions, typically function within a narrow temperature range. Oxygen availability also affects microbial distribution. Although oxygen is required for metabolism in many microbes, it is toxic to other species. The pH of the environment also influences microbial growth. While most microbes thrive in neutral conditions, some species can only metabolize and grow in either very acidic or very alkaline environments. In this laboratory you will investigate the importance of the fourth environmental variable determining the distribution of microbes: osmolarity.

Question 39

Understand osmolarity

Answer 39

Osmolarity refers to the concentration of solutes within a solution. Typically, microbes contain a high number of solutes within their cytoplasm which makes them susceptible to osmotic changes. For example, if a microorganism is placed into a solution with high osmolarity (hypertonic), such as a very salty solution, water from within the cytoplasm will move out of the cell. With the loss of water the stability of the cell membrane and other structures is reduced and the cell will shrink (crenate) eventually leading to cell death. Conversely, if a microorganism is placed in a solution with low osmolarity (hypotonic), such as distilled water, water will move into the bacterium. See Figure 2. If the cell wall is unable to mediate the influx of water, the cell will burst.

Question 40

Hypertonic

Answer 40

For example, if a microorganism is placed into a solution with high osmolarity (hypertonic), such as a very salty solution, water from within the cytoplasm will move out of the cell. With the loss of water the stability of the cell membrane and other structures is reduced and the cell will shrink (crenate) eventually leading to cell death.

Question 41

Hypotonic

Answer 41

Conversely, if a microorganism is placed in a solution with low osmolarity (hypotonic), such as distilled water, water will move into the bacterium. See Figure 2. If the cell wall is unable to mediate the influx of water, the cell will burst.

Question 42

Isotonic

Answer 42

Equal concentration of solutes both inside and outside of the cell

Question 43

Halophiles vs. Halotolerant

Answer 43

HALOTOLERANT - microbes are able to survive at high salt concentrations but do not require these conditions for growth

HALOPHILES - they require a high salt concentration for growth

Question 44

Understand experiment and the results observed

Answer 44

Go to HOL-INTERACTIVE

Question 45

Understand the 1918 pandemic

Answer 45

• Kills nearly 40,000 americans each year
• One of Americas deadliest viruses
• Flu can mutate endlessly
• No strain has ever been as lethal as 1918
• Could be 30,40 or 50 million
• Next flu pandemic is overdue
• Why was 1918 virus so lethal
• Very surprised if its not within 5 to 10 years
• No one knows but believes it started in America (soldiers become ill in Kansas during training)
  o 522 cases
• 48 soldiers die of the flu in the spring
• Lots of soldiers go to Britain and bring the flu
• 3 day fever or called the Spanish flu
• King was sick
• Flu moved freely between Americans, French, and British
• Phone, transit and ammunitions break down
• James Niven in Manchester England was bewildered (he had cut down the cities TB outbreak in half)
• Thought it was German biological warfare but they were also suffering
• In Britain, it followed the railways
• War enabled the flu to become more deadly because of stress, rations, large movement of people, not good living conditions
  o 2nd wave started in Boston, Brest France, and Freetown Africa
• 100 soldiers per day in Boston
• Influenza with something extra
  o Heliotrope cyanosis (discoloration of face and ears)
  o This flu targeted young and healthy 25-34
• Call for doctors to come back from war to help at home but troops were denied quarantine because they needed them
• 500 people a week died in Berlin
• Armistice came on Nov 11
• Ada’s whole family died except for her (her mom, dad, and little brother)
• Influenza starts in birds and gives it in droppings (goes from birds to chickens to pigs)
• Obligate intracellular parasite – influenza
• Virus has only 8 genes but its not locked in a fixed structure
• 100 slivers of lung tissue taken in 1918
• Virus had escaoed victims before their secondary infection
• Found piece of virus in Russo Vaughan and used PCR to make multiple copies
• New virus occurs that it replicated and transmitted well from person to person and once it got into humans, there was nothing that could stop it
• John Oxford wonders if it was in Northern France sooner than 1918
  o 1917 report in strange respiratory disease in Etaples
  o Brought piggeries into the camp
  o Checked in anyone in the camp had live birds, chickens, or pigs
  o Need lots and lots of people
• More people died through sickness then war called purulent bronchitis
  o Died of asphyxiation and cyanosis
• Harry Underdown was one of the first and was needed in France
  o Suffered shell shock in war
  o After 1 month went back to France and he was in the trenches
  o In stress, all resistance to disease drops
  o Feb 21, 1917 he died at 21 yrs old
  o Lungs were choked with blood
  o William Leichman made a connection
• John Oxford thinks the killing fields in 1916 was where the disease started
• Absence of material makes it all speculative
• Identified 6 of 1918 flu genes
• Bringing deadliest virus back to life in Altlanta and combined flu genes to modern flu
• Modern antibody drugs were able to help the rats heal
• There is either a worst or best case scenario
  o Worst is that its worse than Spanish flu
  o Best is 10 -15 million people dying

Question 46

Understand some of the key symptoms of the Spanish flu including heliotrope cyanosis

Answer 46

Asphixyation, cyanosis, choking with blood, heliotrope cyanosis,

The first wave of the 1918 pandemic occurred in the spring and was generally mild. The sick, who experienced such typical flu symptoms as chills, fever and fatigue, usually recovered after several days, and the number of reported deaths was low.

However, a second, highly contagious wave of influenza appeared with a vengeance in the fall of that same year. Victims died within hours or days of developing symptoms, their skin turning blue and their lungs filling with fluid that caused them to suffocate. In just one year, 1918, the average life expectancy in America plummeted by a dozen years.

Question 47

Understand what a super virus is and why it occurs

Answer 47

lots of mutations, influenza strains switch H and N with each other. Because of the war and the major transportation. The virus got moved around a lot and therefore could mutate a lot which

Question 48

Understand the theory behind why the Spanish flu hit certain age groups harder than others

Answer 48

There may have been a influenza strain with similar structure to that of the 1918 flu virus in the 1800s, so some of the older generations would have already been exposed to it. They were able to have antibodies to attack the Spanish flu while the 25-34 year-olds and the children did not have the antibodies.

Question 49

Understand how the Spanish flu spread so quickly

Answer 49

World War 1 soldiers shipping in and out and in and out

spread freely between American, French, and British

Question 50

Why is it called the Spanish flu? Where was it first identified?

Answer 50

The British censored their newspaper, so it did not seem as big of a deal as it actually was; however, the Spanish did not censor their newspaper. The Spanish newspaper was saying things like major epidemic, thousands are dying, many other things related to the reality of the circumstance as well as a little embellishment as most newspapers do. This is why people coined the 1918 flu as the Spanish flu.

• No one knows but believes it started in America (soldiers become ill in Kansas during training)
  o 522 cases

lots go to britain and bring the flu

but later identified that it may be Etaples where it began

Question 51

Know some of the examples of how the rates would fluctuate.

Answer 51

• War enabled the flu to become more deadly because of stress, rations, large movement of people, not good living conditions
  Starts with British, French, and America some in Germany too
  o 2nd wave started in Boston, Brest France, and Freetown Africa

Question 52

Understand how we have since identified the genetic sequence of the 1918 virus

Answer 52

• Virus has only 8 genes but its not locked in a fixed structure
• 100 slivers of lung tissue taken in 1918
• Virus had escaoed victims before their secondary infection
• Found piece of virus in Russo Vaughan and used PCR to make multiple copies
• Identified 6 of 1918 flu genes
• Bringing deadliest virus back to life in Altlanta and combined flu genes to modern flu
• Modern antibody drugs were able to help the rats heal
• There is either a worst or best case scenario
  o Worst is that its worse than Spanish flu
  o Best is 10 -15 million people dying

Question 53

Understand the likely animal origins of the virus

Answer 53

• Influenza starts in birds and gives it in droppings (goes from birds to chickens to pigs)
  Birds and pigs

piggeries were brought into Etaples camp where it likely mutated and spread to Americans

Question 54

What was significant about Etaple and why?

Answer 54

• John Oxford wonders if it was in Northern France sooner than 1918
  o 1917 report in strange respiratory disease in Etaples
  o Brought piggeries into the camp
  o Checked in anyone in the camp had live birds, chickens, or pigs
  o Need lots and lots of people
• Harry Underdown was one of the first and was needed in France
  o Suffered shell shock in war
  o After 1 month went back to France and he was in the trenches
  o In stress, all resistance to disease drops
  o Feb 21, 1917 he died at 21 yrs old
  o Lungs were choked with blood
  o William Leichman made a connection

Professionals speculate that the 1916 virus in Etaples may actually have been the beginning of the 1918 virus. One of the soldiers named Harry had the same heliotrope cyanosis and all of the signs and symptoms of the 1918 virus. His superior noticed the connection and sent in that he may have had the same strain of virus. It spread so quickly because the soldiers in Etaples were in trench warfare and when you are in that much stress and those living conditions, you have basically no resistance to disease. The virus spread very rapidly in Etaples and then began spreading to other places when the soldiers got shipped out and back in.

Question 55

Think of the similarities and differences between the 1918 pandemic and the 2020 pandemic

Answer 55

They were correct that the transmission would spread more rapidly because of all of our airports and different means of transportation. It did catch us by surprise and probably killed more people than our modern medicine was able to handle in the beginning. However, this makes sense since it was a completely new strain of virus that the world had never seen before and needed to study it before they could make a vaccine. I think it was interesting to see the use of masks in the 1918 Spanish flu. That is something that we have learned and used moving forward which helped decrease the rate of infection. I do not know if we knew that human viruses could originate from bats before the COVID-19 pandemic. Overall, I think that the virus spread more quickly because of our modern transportation but that we were able to decrease the mortality rates quicker because of modern medicine.

Question 56

Understand what an ELISA test is and why you would perform one

Answer 56

Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can be used also outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

This virtual laboratory will demonstrate how such a test, termed an enzyme-linked immunosorbent assay (ELISA), is carried out and some of the key experimental problems that may be encountered. Students will learn about the assay procedure and the equipment and materials that are needed. By completing this exercise, students will gain a better understanding of experimental design, key concepts in immunological reactions, and interpretation of data.

Question 57

Understand how to read an ELISA test

Answer 57

This test quantifies how much enzyme is present by the amount of color produced. The more enzyme present, the more secondary antibody must be attached. The amount of secondary antibody present is determined by the amount of target, or first antibody, available. Finally, because the first antibody binds to antigen, the more antigen that is accessible, the more first antibody will be retained. The measure of color, therefore, reflects the amount of antigen initially present.

Question 58

Understand antibodies including where they are found and function

Answer 58

Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can be used also outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

Question 59

Understand what errors can occur with an ELISA test

Answer 59

ELISA is used in many laboratories to determine whether a particular antibody is present in a patient’s blood sample. Although the procedure is routine and straightforward, it involves a number of variables, such as reagent selection, temperature, volume measurement, and time, which if not adjusted correctly can affect subsequent steps and the test outcome. This virtual laboratory has been developed so that when a mistake is made, you will not get the correct answer. The program keeps track of errors made throughout the experiment and generates a report at the end.

Question 60

Understand the limitations of an ELISA test

Answer 60

First, a positive result correctly confirming the presence of antibody does not necessarily mean the patient is sick. The body can continue to produce antibodies even though the person may have had the disease earlier and recovered.

Second, people may be poor producers of antibody or may have some interfering substance in their blood. The amount of antibody, consequently, may be too low to measure accurately or may go undetected. This result is termed a false negative.

Third, a positive result may occur if an unrelated antibody reacts with the antigen nonspecifically. Unlike a true-positive result where the specific antibody is detected, however, this positive reaction is false. Testing many patients and running tests more than once helps lab workers distinguish a true from a false result. To avoid simple experimental mistakes leading to incorrect results, scientists conduct tests using duplicate (or, sometimes, more than two) samples.

Question 61

Understand the components of blood

Answer 61

• Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in.
• Red blood cells are responsible for carrying oxygen and carbon dioxide.
• Platelets are responsible for blood clotting.
• White blood cells are part of the immune system and function in immune response.

Plasma, the liquid component of blood, can be isolated by spinning a tube of whole blood at high speeds in a centrifuge. The denser cells and platelets move to the bottom of the tube, forming red and white layers, while the plasma remains at the top, forming a yellow layer.

The plasma is about water, with the remaining made up of ions, proteins, nutrients, wastes, and dissolved gases. The ions, proteins, and other molecules found in plasma are important for maintaining blood pH and osmotic balance, with albumin (the main protein in human plasma) playing a particularly important role.

Some of the molecules found in the plasma have more specialized functions. For example, hormones act as long-distance signals, antibodies recognize and neutralize pathogens, and clotting factors promote blood clot formation at the site of wounds. (Plasma that’s been stripped of its clotting factors is called serum.) Lipids, such as cholesterol, are also carried in plasma, but must travel with escort proteins because they don’t dissolve in water.
Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can be used also outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

Question 62

Understand the steps to complete an ELISA test

Answer 62

The interaction of antigen and antibody outside the body–in the laboratory–can be used to determine if a patient has an infectious or an autoimmune disease. The test measures whether a specific antibody associated with an illness can be found in a patient’s blood. A positive result indicates that the antibody is there and implies that the person has encountered a particular disease.

This exercise begins with removing red and white blood cells, which can interfere with the test, from a patient’s blood sample. The watery fluid that remains is called serum. A portion of serum possibly containing the antibody is allowed to react with the target antigen. A correct match causes the antigen and antibody to bind together.

Detection becomes possible when a second antibody is added. This antibody is prepared from the serum of an animal injected previously with human antibody; the human antibody in this case serves as an antigen and the animal thus produces an antibody against the human antibody. Once isolated, the second antibody can be chemically linked to a system that can produce a detectable signal.

In ELISAs, the antigen antibody complex is exposed to the second antibody, which binds to the antibody portion of the complex (against which it was formed), creating a sandwich-type structure (Figure 1). The signaling system consists of an enzyme attached to the second antibody. When the appropriate chemical is added, the enzyme converts it to a colored substance that can be measured.

This test quantifies how much enzyme is present by the amount of color produced. The more enzyme present, the more secondary antibody must be attached. The amount of secondary antibody present is determined by the amount of target, or first antibody, available. Finally, because the first antibody binds to antigen, the more antigen that is accessible, the more first antibody will be retained. The measure of color, therefore, reflects the amount of antigen initially present.