Microbiology Final (Sessions 2 - 8, Diseases and Biosafety) Flashcards
(193 cards)
1
Q
What causes anthrax?
A
Bacteria (bacillus anthracis)
2
Q
What is the treatment for anthrax?
A
antibiotics
3
Q
How is anthrax transmitted?
A
Spores get into the body (breathed in, ingested, through scrape or cut, injection).
4
Q
How do you diagnose anthrax?
A
Measuring antibodies or toxin in blood. Testing for B.anthracis in body fluid or tissues.
5
Q
How can you prevent anthrax?
A
Vaccine only given to high risk people. Antibiotics in exposed people.
6
Q
Anthrax threat to health care providers.
A
Unlikely to be a high risk of infection.
7
Q
What do you call a pathogen that can cause disease in both humans and animals and is transferable between them?
A
Zoonotic pathogen
8
Q
The main difference between risk group 3 and 4 is that the risk to public health is low is risk group 3, and high in risk group 4, despite the fact that the pathogens in each group are very likely to cause serious disease. What is the key fact that determines this difference?
A
Effective treatment and preventative measures are usually available in risk group 3 and not usually available in risk group 4.
9
Q
Why can some certain risk group 1,2,3 pathogens be housed within a certain containment level that does not correspond to their risk group level?
A
Depending on the pathogens characteristics, and the work being done with the pathogen (planned activities), the level of containment can vary among the different risk groups.
10
Q
Describe a risk group level 3.
A
The level 3 risk group is considered to be any pathogens or toxins that are high risk to individuals and animals with a low risk to the community.
11
Q
Who are the only individuals likely to be affected by a risk group 1 (RG1) pathogen?
A
Immunocompromised individuals.
12
Q
Ebola is a highly infectious, and lethal pathogen that can cause serious economical and health implications on a society, which level of contamination would it most likely be handled in?
A
Since Ebola is a highly lethal pathogen, it must be handled in containment level four, due to that level having specific engineered controls that help prevent the spread of any pathogens from the laboratory.
13
Q
Name the 4 risk groups and briefly explain what each group means and provide an example of each.
A
Risk group 1: A pathogen that has been determined a low health risk for individuals and the public. Example: Lactobacillus acidophilus-
Risk group 2: A pathogen presenting a moderate health risk to individuals but low risk for the public. Example: Listeria monocytogenes
Risk group 3: A pathogen presenting a high risk to individuals but low risk to the public. Example: SARS
Risk group 4: A pathogen presenting a high risk for both the public and individuals. Example: Ebola Virus
14
Q
Why should we document right after an incident occurs?
A
To promote the accuracy of the information documented with complete detail and diminish the effect of a recall bias. It is also useful because then the information gathered can allow for valid comparison with other incidents.
15
Q
What is an example for the route of exposure Inoculation?
A
Getting poked by a dirty needle
16
Q
Give three reasons why LAI’s are underreported.
A
a. Many LAI’s are asymptomatic (the individual doesn’t even realize they have an infection
b. Many workers feel there is a possibility of punishment
c. Many countries don’t have a legal requirement or mechanism to report
17
Q
What is the difference between an accident and an incident?
A
An accident is an event that results in injury or damage whereas an incident is an event that has the potential to cause injury or damage.
18
Q
Why are laboratory acquired infections dangerous?
A
Because an infected worker may pose a risk for secondary transmission to the general public.
19
Q
Why is it important to report any incidence of exposure or contact with a microbe?
A
Some microbes may be symptomatic or asymptomatic so its important to be extra cautious to protect the general public and also receive medical attention for any exposures.
20
Q
What is an exposure? What are the different routes of exposure?
A
Exposure is coming in contact with or very close to an infectious biological material. The different routes of exposure are: i. Inhalation (via aerosols) ii. Inoculation (needle sticks or bites) iii. Ingestion (through the mouth or contamination of food and drink) iv. Absorption (through splashes or spills on skin and mucous membranes).
21
Q
What kind of source of infection is a concern for blood borne viruses?
A
Needle, syringe
22
Q
What is the greatest biohazard facing laboratory workers?
A
Airborne particles
23
Q
The inconsistent use of _______ and the questionable integrity of them has been anecdotally associated with LAI’s.
A
Gloves
24
Q
Whose responsibility is it to make sure that decontamination occurs properly, and should you trust other to have followed decontamination protocol accurately?
A
Everyone who comes in contact with pathogens should take responsibility to promote health and safety by decontaminating materials. It should not be assumed that tools and surfaces have been decontaminated properly by others. If you are unsure and feel their may be a hazard, it is your responsibility to keep yourself and others safe by decontaminating them again before use.
25
What is one microorganism that can be killed using a low-level disinfectant such as sanitizer?
A fungi, vegetative bacteria, or enveloped virus
26
What is the causal agent of diptheria?
bacterium, corynebacterium duotheriae
27
How is diptheria transmitted?
Via respiratory tract through droplets. Less commonly through direct contact with contaminated fomite or milk.
28
How is diptheria diagnosed?
Signs and symptoms plus lab culture results (throat or lesion swab)
29
What is the treatment for diptheria?
antibiotics
30
How can diptheria be prevented?
vaccine
31
What are precautions for health care workers for diptheria?
Droplet precaution, gloves and hand hygiene
32
Define microbe.
Very small, living or non-living organisms (or infectious elements) that usually cannot be seen with naked eyes. They can be cellular or acellular, they can be autotroph or heterotroph, motile or sessile.
33
Who was the first to see and describe a microbe and use a microscope?
Robert Hooke
34
Who was the first person to observe and describe a bacteria?
Antoni van Leewenhoek
35
Who disproved the theory of spontaneous generation?
Pasteur
36
Who proved the link between causal agents and infectious diseases?
Robert Koch
37
Who discovered penicillin?
Alexander Flemming
38
Who first used phenol to sterilize surgery tools and wounds and conducted the first aseptic surgery?
Joseph Lister
39
What is the causal agent of COVID-19?
Severe Acute Respiratory Syndrome-Related Coronavirus-2 (SARS-CoV-2). SARS-CoV-2 is a Single-stranded, positive-sense RNA, enveloped Virus
40
How is COVID-19 transmitted?
COVID-19 is transmitted through respiratory droplets and becomes an airborne particle. COVID-19 virion can live on surfaces and can be transmitted by contacting the surfaces then touching the face.
41
What is the incubation period for COVID-19?
The incubation period for COVID-19 is currently one, to fourteen days with eleven days being the average timeframe, during this time the host can infect another person for up to three days prior to any symptoms developing.
42
How is COVID-19 diagnosed?
Nucleic acid amplification (PCR)
43
How is COVID-19 treated?
Currently there is no global cure, or global vaccine to treat COVID-19
44
How do you prevent COVID-19?
- Due to its high transmission rates there should be limited close proximal contact with infected hosts
- Physical distance with a host should be maintained at a minimum of 6 ft, due to the possibility of transmission with asymptomatic, pre-symptomatic, and symptomatic hosts it is difficult to know who a carrier is and who is not
- When a high population of people ware masks the rate of transmission decreases significantly
45
Risk of COVID-19 to health care professionals.
Healthcare Professionals are at risk of developing severe symptoms due to exposure to higher viral load of COVID-19, and from fatigue of working long hours
46
What causes ebola?
Ebola virus
47
How is ebola transmitted?
Bats are reservoir hosts for the virus. Infected bats transmit the virus to nonhuman primates, which then infects humans through direct contact. Human to human transmission occurs via direct contact (through broken skin/mucous membranes) with blood, tissue or other body fluids of infected individuals and through sexual transmission. It can also occur via indirect contact (through contaminated medical equipment or environmental surfaces).
48
How is ebola diagnosed?
Ebola is diagnosed based on symptoms, travel history and laboratory testing.
Laboratory tests to diagnose Ebola include: Immunofluorescence techniques and Polymerase chain reaction (PCR).
49
How do you treat ebola?
There is currently no cure for Ebola. Patients are only treated to help with the symptoms which includes: supporting blood pressure and oxygen delivery, ensuring that the patient’s fluid and electrolytes level are within normal range and strict isolation in an intensive care unit (this is for the prevention in the spreading of the disease).
50
How can you prevent ebola?
First prevention is to avoid direct contact with bodily fluids of people with Ebola (e.g. urine, blood, saliva, vomit, semen and breast milk).
Second, is to avoid direct contact with bodies of people who have died of Ebola or any unknown diseases and to avoid direct contact with medical equipment such as needles that were contaminated with blood or bodily fluids; and lastly is to avoid contact with live and dead animals such as Monkeys, Fruit bats.
51
What impacts are there of ebola to health care professionals?
Strict infection control measures should be practiced. Isolate infected individuals, use personal equipment like gowns, masks, gloves and goggles properly (to block splashes or other contact with infected materials), disinfect or dispose instruments and equipment properly, perform basic hand and respiratory hygiene, and perform safe injection and burial practices.
“CDC recommends that all healthcare workers entering the room of a patient with Ebola wear respiratory protection that would protect them during an aerosol-generating procedure. This would include a NIOSH-certified, fit-tested N-95 or higher respirator, or a PAPR.”*.
52
What is often done before sterilization or disinfection to reduce the number of micro-organisms on an object?
Objects are often cleaned first to remove soil or organic material, especially heavily soiled objects.
53
What microorganisms are the most susceptible to disinfection?
Vegetative bacteria, particularly gram-positive bacteria, fungi, and enveloped viruses
54
True or False. Enveloped viruses are harder to kill than naked viruses with low-level disinfectants?
False
55
Put the following in order of least resistant to most resistant: bacterial endospores, fungal spores, prions, enveloped viruses, non-enveloped viruses.
Enveloped virus, Fungal spore, Non-enveloped virus, Bacterial endospore, Prion
56
What is the single most important method to prevent the spread of infection?
Proper handwashing technique
57
Which prion disease can affect both livestock and humans alike, but goes by different names based on its host?i)
Bovine Spongiform Encephalitis or Creutzfeldt-Jakob Disease.
58
Pathogen Safety Data Sheets (PSDS) are sheets that identify the risks of pathogens and explain how to properly handle potentially harmful pathogens in a laboratory environment, what is one downside to the Pathogen Safety Data Sheet?
Although PSDS contain crucial information regarding certain pathogens, the pathogen safety data sheet does not contain information about every pathogen, therefore, it isn’t guaranteed to help students deal with pathogens.
59
Killing, inhibiting, or removing micro-organisms that may cause disease. Usually carried out through thermal, chemical, or radiological-processes.
a. Sterilization
b. Decontamination
c. Cleaning
d. Disinfectant
Disinfectant
60
What are 2 disadvantages of incineration?
Living organisms may be released because of changes in the waste content and the equipment hazardous pollutants could be put into the environment.
61
What are the four methods of decontamination?
Sterilization-Disinfection-Decontamination-Cleaning
62
Plasma torches are used in decontamination and can reach a temperature range of
between 3000 degrees Celsius and 8000 degrees Celsius
63
Name the most appropriate form of decontamination and disposal that a cancer center would need for the drugs they use to treat and kill cancerous cells in their patients.
Incineration
64
What are two types of steam decontamination methods?
Autoclaves and biowaste cookers
65
While incineration is an effective decontamination method, it also has many disadvantages. One of these disadvantages are that the incineration is bad for the environment. Why is this the case?
During the burning of the waste, microorganisms and many chemical pollutants may be released into the environment. It is for this reason that incineration often times does not even meet emission regulations.
66
Although there are many methods of decontamination, what is the preferred method of decontamination in laboratory settings?
Autoclaving is the preferred method for decontamination for laboratory settings, because it uses a sealed and controlled chamber to sterilize materials.
67
How are cytotoxic drugs handled in facilities?
They are handled in a similar way to biomedical waste but with one vital difference, they must be isolated from other biomedical waste. It is also important to not refrigerate or autoclave cytotoxic drugs they must be incinerated.
68
What kind of training must the employer provide before an employee can handle hazardous matter?
Training must be given on the recognition, packaging, transport, and the proper way to handle and store hazardous matter.
69
What type of biomedical waste poses the greatest risk for exposure to pathogens?
Sharps-related accidents pose the greatest risk for workers handling biomedical waste when they are not separated from other waste properly or caused by containers breaking.
70
True or False? Gloves have been used in the lab and now have to be thrown out. It has come in contact with an infectious material. It should still be placed in the regular garbage.
False, it is a biomedical waste because of the infectious contact.
71
A laboratory worker is disposing of cytotoxic waste, what are some special considerations?
Cytotoxic waste should be separated from other wastes, it should be labelled as “cytotoxic waste,” and it should not be refrigerated but it should be incinerated
72
What are four reasons why it’s important that establishments have a proper waste management program?
The four reasons are that if there is not a waste management there can be poor risk management, occupation safety risks, contamination to the environment and a possible breach to the containment of contagious diseases.
73
What type of biomedical waste container is ridged, leak proof, sealable and puncture resistance?
a. Sharps container
b. Reusable waste container
c. Cardboard container
d. Plastic waste holding bag
a. sharps container
74
Biomedical waste management is extremely important, waste is separated into two sections, hazardous and non-hazardous, however, cytotoxic waste must be segregated from both of those sections, why?
Cytotoxic waste which is used in cancer treatments has the ability to kill living cells and tissues, therefore, it is extremely important that it be isolated from all other types of waste because it could be accidentally released and cause biological problems for individuals in contact with the material.
75
What are the 3 major criteria for classifying viruses?
The type of nucleic acid (DNA or RNA); 2) the presence or absence of an envelope; 3) the manner of replication
76
Briefly list Koch's postulates.
1. The suspected pathogen must be present in all cases of the disease and absent from healthy animals.
2. The suspected pathogen must be grown in pure culture.
3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal.
4. The suspected pathogen must be reisolated and shown to be the same as the original.
77
Who disproved the theory of spontaneous generation?
Pasteur
78
Briefly explain the theory of spontaneous generation and the theory of bio biogenesis.
Spontaneous generation is that in certain conditions non-living items can produce life (e.g. rotten meat gives life to maggots and flies). Biogenesis: life begets life.
79
List the high-level characteristics of bacteria.
Cellular, prokaryote, unicellular
80
List the high-level characteristics of protists.
cellular, eukaryote, uni or multicellular
81
List the high-level characteristics of fungi.
Cellular, eukaryote, uni or multicellular
82
List the high-level characteristics of microscopic animals (parasitic worms)
Cellular, eukaryote, multicellular
83
List the high-level characteristic(s) of viruses
acellular
84
List the high-level characteristic(s) of protists
acellular
85
Explain the structure of prokaryotic and eukaryotic microbial cell structure
All cellular microbes have a cell membrane, cytoplasm, and ribosomes and with the exception of microscopic animals, all have a cell wall.
Unlike prokaryotes, eukaryotic microbes have nucleolus, endoplasmic reticulum, and other membrane-bound cell organelles such as mitochondrion.
The nucleus is found only in eukaryotic microbes. Chromosomes are located in the nucleus.
Eukaryotic cells have linear chromosomes while DNA in prokaryotic microbes is circular. Bacteria have a special set of small and circular genetic elements called plasmids. Plasmids carry genes responsible for antimicrobial drug resistance.
86
List some characteristics of gram positive bacteria.
```
Stain blue-or purple
Has a thicker peptidoglycan layer
Only one membrane
Makes it more sensitive to things like antibiotics
Embedded proteins
```
87
List some characteristics of gram negative bacteria.
Stain red or pink
Has a thinner peptidoglycan layer
Has two membranes
Embedded proteins
88
What is the structure and function of capsules and slime layers.
Less likely to be eaten through phagocytosis
Function: Assist in attachment to surfaces
Protect against phagocytosis
Resist desiccation
89
What is the structure and function of fimbria?
Filamentous protein structures
| Enable organisms to stick to each other or to surfaces (main job)
90
What is the structure and function of pilus?
```
Filamentous protein structure
Typically longer than a fimbria
Assist in surface attachment
Facilitate genetic exchange between cells
Some involved in motility
```
91
Briefly explain phagocytosis.
Endocytosis. "cellular eating" Piece of membrane wraps around the food particle called a food vacuole.
92
Briefly explain pinocytosis.
Endocytosis. "cellular drinking". water; creates a coated vesicle
93
Briefly explain receptor mediated endocytosis
Endocytosis. Protein - very specific to certain types of molecules.
94
Explain the process of spore formation in bacteria and its ecological importance.
Highly differentiated cells resistant to heat, harsh chemicals, and radiation
A bacteria will develop a spore when it is faced with harsh environmental conditions so that it will survive (save my generation! If I stay vegetative I will die)
Only gram positive bacteria produce spores
The cell wall of an endospore if very tough (hand sanitizer will kill all but one - C-difficile)
An endospore doesn’t mutate or divide; it waits until conditions improve
In the endospore there is DNA, ribosomes.
95
Why smaller microbes (e.g. bacteria) are able to adapt to a changing environment (e.g. presence of antibiotics) faster than other living organisms like humans?
Simpler structures
More generation (divide at a faster rate) at a given time; able to mutate faster
Mutation is key to adaptation
Greater surface area (S/V ratio)
96
What is the cell wall made of in fungus?
Chitin
97
What is the cell wall made of in bacteria?
Peptidoglycan
98
What is the cell wall made of in protists?
Cellulose
99
Describe simple stain.
Single dye, used to determine size, shape and arrangement of cell (e.g. crystal violet)
100
Describe differential stain.
Uses more than one type of dye, differentiates between different structures (e.g. gram stain)
101
Describe special stains.
Special cell features, capsule or flagella, stain the background but cells are clear. (e.g. flagellar stain)
102
What is the causal agent of gonorrhea?
Neisseria gonorrhoeae bacterium
103
How is gonorrhea transmitted?
Is a Sexually Transmitted Disease (STD)
- Epithelial cells of mucous membrane come in contact with mucous membrane secretion during anal, vaginal and/or oral sex.
- An infected mother can transmit it to baby through the child birthing process.
104
How is gonorrhea diagnosed?
- Nucleic acid amplification tests (PCR)
| - Culture
105
How is gonorrhea treated?
Antibiotics (some strains are antibiotic resistant)
106
How can you prevent gonorrhea?
- Abstaining from sex is the most sure fire way to prevent gonorrhea.
- But if you choose to have sex, use a condom during any type anal sex, oral sex or vaginal sex.
- Ask your partner to be tested for sexually transmitted infections.
- Regular gonorrhea screening (esp. if multiple or new partners)
107
Risk of gonorrhea to health care professionals
Low risk from patients; Standard PPE
108
What is the causal agent of Hepatitis B?
a virus
109
How is Hep B transmitted?
~ Sharing of drug equipment or contaminated medical/dental equipment
~ High risk sexual activity
~ Being born to a mother with HBV or in a region where HBV is widespread
~ Sharing razors, scissors, nail clippers or toothbrushes with an infected person;
~ When unsterile equipment or techniques are used during tattooing, body piercing or acupuncture
~Exposure in the workplace by getting pricked by a needle or sharp equipment that had infected blood or body fluids on it
110
How is Hep B diagnosed?
Immunofluorescence and PCR
111
How is Hep B treated?
Acute
~ If known within 7 days of possible contact with HBV you can receive an injection that may prevent development of disease
~ Those who have acute HBV the virus will usually go away on its own within 6 months.
~ Health care providers concerns with acute HBV is treating symptoms and maintaining adequate nutritional balance (insuring liver failure does not occur). Also a focus of preventing transmission.
Chronic
~ Two types of medication used interferon (injection) and antiviral (oral)
112
How do you prevent Hep B?
~ Number one way to prevent the transmission of HBV is to receive the vaccination.
~ Practice safe sex
~ Avoid using other people’s drug equipment, razors, scissors, or dental hygienics.
~ Make sure acupuncture, dental/medical and tattooing equipment is sterile.
Those Living with HB
~ Never donate blood, tissue, organs or semen
~ Ensure family members are immunized and tested for HB
~ Cover open sores or breaks in your skin
~ Health care providers wear PPE when handling blood/bodily fluids of patients with HB
113
What is the causal agent of Hepatitis C?
Hepatitis C virus
114
How is Hep C transmitted?
Blood-borne disease transmitted via infected blood and body fluids.
115
How do you diagnose Hep C?
Nucleic acid amplification (PCR) and immunofluorescence
116
How do you treat Hep C?
Specific antiviral drugs determined by genotype.
117
How can you prevent Hep C?
Currently, there is no vaccine for Hepatitis C. Use clean, sterile equipment. Use safe sex practices. Do not share personal care items
118
What are the risk factors of Hep C for health care professionals?
Needle sticks, sharps, or mucosal exposures to HCV-positive blood can transmit the virus to HCWs.
119
What is the causal agent of Hep A?
positive sense, single stranded RNA virus
120
How is Hep A transmitted?
Transmission (where there is a lack of hand hygiene in all factors)
• Transmitted through consumption of fecally contaminated food & water (fecal oral route) where there is a lack of hand hygiene.
• Close physical contact with infected people
o Daycares, households, schools
o Sexual contact
• Certain raw food such as shellfish, fruits or salads
• Food made in unclean conditions or by an infected person with unsafe food handling practices
121
How is Hep A diagnosed?
Immunofluorescence
| Nucleic acid amplification
122
How do you treat Hep A?
No specific treatment for Hepatitis A. Recovery is slow and can range from a few weeks to months.
123
How can Hep A be prevented?
* Immunizations are the most effective.
* Proper hygiene (body & food)
* Hand washing (so the virus cannot be transferred)
* Proper sewage disposal to prevent other people from coming into contact with the infected waste products
124
Risk of Hep A to health care professionals
* Lack of hand hygiene.
* Eating on the hospital wards
* Not being immunized, especially for individuals who have to work in close proximity the infection
125
What is the causal agent of human papillomavirus?
Non-enveloped virus
126
How is HPV transmitted?
* HPV can be contracted even if someone does not have penetrative sex. It can still be transmitted through genital skin to skin contact.
* Transmission can occur even if no signs, such as genital warts occur.
* Sexually transmitted disease
127
How is HPV diagnosed?
```
If genital warts aren’t visible you can do the following;
• Vinegar solution test
• PAP test
• DNA test
• Digene hybrid capture 2
```
128
How is HPV treated?
* No cure
* The immune system clears 90% of cases within 2 years
* Genital warts can be removed by Imiquimod cream, freezing, burning, laser treatment, or injection of alpha interferon
* Abnormal cervical tissue cells can be removed via freezing, conization, or laser therapy.
129
How can you prevent HPV?
* Get vaccinated at age 11-12, 2 doses
* Routine screening for women 21-65
* Wear a condom even though it does not fully protect
130
Does HPV pose any special risk to health care providers?
* HPV is a sexually transmitted disease and does not pose any special risk to HCP’s
* Practice using proper PPE when handling HPV patients
131
What is the causal agent of influenza?
RNA virus
132
How is the flu transmitted?
spread through the transmission of contaminated airborne droplets such as those expelled from an infected person during coughing or sneezing. Those droplets may also contaminate objects which then may also contribute to the spread of the virus.
The flu can also travel by bird (avian) or pigs (swine).
133
How do you diagnose influenza?
Nucleic acid amplification (PCR)
134
How do you treat influenza?
Symptomatic treatment for mild cases includes bed rest, consuming plenty of fluids, and over the counter medications to reduce fever and aches. Antiviral medications can be used.
135
How can you prevent influenza?
Annual Influenza vaccination is the best way to prevent the spread of the Influenza virus. The vaccine provides immunity to several strains of the virus which are predicted to be the most common strains in the upcoming flu season.
136
Does influenza pose any special risk to health care providers?
Wear personal protective equipment, practice proper hand hygiene, and disinfect/sanitize all medical equipment used. Mandatory influenza vaccination is required. Pre-exposure and post-exposure antivirals may be prescribed to prevent infection for health care workers depending on type of exposure and risk associated with exposure.
For pandemic cases of influenza such as H1N1, H5N1 CDC recommends at least N-95 respirators for healthcare professionals providing care to patients.
137
What is the causal agent for Lyme disease?
bacteria
138
How is Lyme disease transmitted?
Transmitted by the bite of an infected tick (vector-borne). Ticks are infected when they feed on birds or mammals that carry the pathogen in their blood. Usually, only nymphs and adults cause infection, not larvae.
139
How is Lyme disease diagnosed?
Immunofluorescence
140
How is Lyme disease treated?
Antibiotics; **Early treatment is very important to avoid further damage (arthritis, meningitis, etc).**
141
How can you prevent Lyme disease?
- No vaccine
- Protective clothing, tick repellents, checking skin regularly
- Wearing clothing that covers exposed skin
- Grab the tick as close to the skin as possible and try not to break off mouthparts
- Skin disinfectant
- Wash off body as soon as possible after entering from outside
- Walk in cleared areas (no forestation)
- Put your clothing in the dryer for 10 minutes or more to kill the tick that might have attached to the clothing
- Try to keep your lawn short (mow often)
142
Does Lyme disease pose any special risk to health care providers?
No real risks pose healthcare professionals. Just have to ensure that the tick is no longer attached to the patient or on their clothes, as it could feed on another person.
143
What is the causal agent of the measles?
• Enveloped virus
144
How is measles transmitted?
* Normally passed through direct contact and through the air.
* Highly contagious
* Virus infects respiratory tract and spreads throughout the body
* Spread by coughing and sneezing, close personal contact/direct contact with infected nasal/throat secretions
* Virus remains active and contagious in the air or on surfaces for up to 2 hours
* Can be transmitted by infected person 4 days prior to onset of rash to 4 days after rash begins
145
How is measles diagnosed?
* Symptoms
* Nucleic acid amplifications
* Immunofluorescence
146
How are measles treated?
* No specific antiviral treatment exists
| * Most cases recover within 2-3 weeks
147
How can measles be prevented?
* Routine measles vaccination for children
* Mass immunization campaigns in places with high case and death numbers to lessen those numbers across the globe
* If measles are contracted, limit interaction with others to lessen the odds of spreading it
* Don’t share drinks, food or utensils
148
Do measles pose any special risk to health care providers?
* Need gown, mask and gloves as PPE and a face shield in case of coughing
* Nurses need to have two rounds of vaccinations documented
* Patients need to be isolated
* Ensure visitors are limed in number, along with being vaccinated, wearing PPE and knowing the risks
149
What is the causal agent of mumps?
enveloped virus
150
How are the mumps transmitted?
* Person-to-person
* Airborne
* Touching contaminated objects with mucus/saliva
151
How do you diagnose the mumps?
* RT- PCR on buccal swabs
* Based on symptoms
* Doctor will confirm infection with lab test
* Vaccination history
* Potential exposure to the virus
152
How do you treat the mumps?
* Rest in bed until the fever goes away.
* Drink plenty of fluids.
* Take over the counter pain relievers.
* Avoid foods that require lots of chewing.
* Isolate yourself or your child to prevent spreading the disease to others.
* Use a warm or cold compress to ease the pain of swollen glands.
* Avoid sour foods.
153
How can you prevent the mumps?
* The vaccination is the best way to prevent mumps.
* Combination MMR and MMRV vaccines.
* Two doses of mumps vaccine are 88% effective.
* One dose is 78% effective.
154
Do mumps pose any special risk to health care providers?
* PPE.
* Transmission in healthcare settings is not common.
* If you suspect mumps in a patients use the mumps reporting form.
* After first dose of MMR, second dose at least 28 days afterwards.
155
How do eukaryotic cells reproduce?
Eukaryotic cells can reproduce asexually (via mitosis) or sexually (via meiosis).
156
Define mitosis.
Mitosis can happen in haploid (Haploid is the quality of a cell or organism having a single set of chromosomes) or diploid (Diploid is a cell or organism that has paired chromosomes, one from each parent.) cells and results in identical daughter cells.
157
Define meiosis
happens only in diploid cells and produces four haploid cells.
happens only in sexual reproduction and it increases genetic diversity in a population.
158
Explain cell division in bacteria.
Bacteria do not have nucleolus and do not have sexual reproduction. Since they do not have nucleus and they cannot do mitosis. They reproduce through a process called binary fission.
Bacteria = binary fission
Binary fission (20 minutes to do binary fission at minimum):
Bacterial DNA replicates to produce two identical copies of the chromosome
Then each chromosome attaches to different part of the cell membrane
As the bacterial cell elongates, DNA copies move to opposite ends of the elongated cell
Lastly, a septum is produced in the middle of the cell to produce two identical daughter cells
159
List some sources of genetic diversity in microorganisms.
- With eukaryotic organisms, meiosis and sexual reproduction generates genetic diversity (think children in humans)
- With bacteria, mutations are a common source of genetic diversity (most important part)
- Another source of genetic diversity is horizontal gene transfer - this is an important tool for bacteria.
160
Describe horizontal gene transfer.
Horizontal gene transfer: the movement of genes between cells that are not direct descendants of one another. It allows the cells to quickly acquire new genes and improves genetic diversity.
161
What are three types of horizontal gene transfer?
transformation, transduction, conjugation
162
Define obligate anaerobe.
Cannot tolerate oxygen.
163
Define Obligate aerobe
need oxygen to produce energy from food
164
Define facultative aerobes
Can survive with or without oxygen
165
List three differences of sexual and asexual reproduction
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Asexual:
Genetically uniform
One organism
Efficient and fast
Simple organisms (bacteria)
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Sexual reproduction
Uniting of two gametes
Diversity
More time consuming (two gametes finding each other)
Harder
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166
What is the most diverse group of eukaryotes?
single cellular protists
167
What protist can cause malaria in humans?
plasmodium
168
Give an example of a multicellular protist.
Pythium, the causal agent of pythiosis. Needs an aquatic environment to reproduce. Spores infect people who are exposed to contaminated water. Human and certain animal skin and hair are chemoattractants for the spores (can swim using flagella),
169
Describe the structure, physiology, and pathogenicity of helminths.
- multicellular, usually anaerobic
- No cell wall but some have a cuticle
- infect 1/3 of the world's population
- some feed while others absorb
- energy is used for reproduction
diverse life cycles and can include multiple hosts
170
List the different modes of transmission of helminths
- fecal-oral
- intermediate host (eating infected tissue)
- transdermal transmission (larva penetrates the skin)
- vector-borne (blood sucking vectors)
171
What are the three groups of helminths?
- tapeworms
- roundworms
- threadworms (pinworms)
(based on their shape)
172
Define virus and virion.
Virus:
-a genetic element that cannot replicate independently of a living (host) cell (i.e. obligate parasite).
Therefore, most scientists do not consider them living organisms.
Most viruses are smaller than prokaryotic cells.
Viruses have no cell organelle such as mitochondrion, nucleus or ER that’s why they are called acellular infectious elements.
Usually a protein shell and a genome
Some have an envelope
The genome is very different from that of other living organisms (made of double strand DNA)
Can have different shapes of DNA
Virion
an extracellular form of a virus
exists outside the host and can infect a living cell when it enters the cell it is activated and is called a virus.
173
Explain how viruses are classified based on their genome structure
Either DNA or RNA genomes
Single stranded (ss) or double stranded (ds)
Single stranded must be plus sense (same as mRNA) or minus sense (complementary to mRNA)
Either linear or circular
174
Explain the structure of naked and enveloped viruses
Capsid: The protein shell that surrounds the genome of a virus particle
Enveloped viruses:
Have lipoprotein membrane surrounding nucleocapsid
Envelope proteins attach to and infect an animal host cell. Common in animal viruses Some are covered in spikes
Unenveloped viruses:
Viruses whose capsids are not covered by an envelope.
The capsid of a nonenveloped virus protects the nucleic acid from nuclease enzymes in biological fluids and promotes the virus’s attachment to susceptible host cells
175
Explain the process of viral replication in a permissive bacterial cell
Attachment, Penetration, Synthesis, Assembly, Release
176
True or false: Animal viruses are mostly enveloped.
True
177
Explain viral life cycle in animal cell.
Bind specific host cell receptors, typically used for cell-cell contact or immune function
different tissues and organs express different cell surface proteins.
often viruses only infect certain tissues.
Entry usually occurs by phagocytosis (virus is treated as a piece of food), receptor-mediated endocytosis, or genetic injection
178
What is the consequence of a virulent viral infection?
lysis of host cell
179
What is the consequence of a latent viral infection?
Viral DNA exists in the host genome and virions are not produced; host cell is unharmed unless/until virulence is triggered.
E.g. shingles
180
What is the consequence of a persistent viral infection?
Release of virions from the host cell by budding does not result in cell lysis.
Infected cell remains alive and continues to produce virus
Though eventually it will be killed by the immune system
(e.g. HIV)
181
What is the consequence of a transformation from a viral infection?
conversion of normal cell into tumor cell
Infects the cell but doesn’t kill it
20% of cancers are caused by viruses
Transformation happens in non permissive cells
182
Explain the ecology and diversity of viruses in nature
Viruses found everywhere cellular life is present
•It is estimated that there are10 times more viruses on earth than prokaryotic cells
•For example in seawater:
•about 106 prokaryotes per ml of seawater
•about 107 viruses per ml of seawater
Five to 50 percent of seawater bacteria killed daily by phage
183
Define virome and explain how human virome can affect human health
Virome: the entire population of viruses present in a sample.
Example:
Human virome = the entire population of viruses present in and on human body
Unique to an individual and relatively stable over time
Human virome consist of some: Animal viruses, Plant viruses (from food), Bacteriophages
Bacteriophages as part of human virome In mucosa of our lung, there are some 20 times more bacteriophages than bacteria. Bacteriophages are anchored to sugar residues produced by mucosal cells.
•They may be the first line of defense against some pathogens and therefore they have a symbiotic relationship with us.
184
What is HERV?
human endogenous retrovirus (HERV) elements constitute 5-8% of human genome. Connections are proposed between some HERVs and certain human diseases such as multiple sclerosis (MS) inflammatory bowl disease (IBD).
185
Explain the structure and life cycle of Hepatitis D virus
Hepatitis D virus (HDV) is a very small RNA virus, it has a capsid, but its genome lacks the genes encoding its own capsid.
HDV needs Hepatitis B virus HBV to produce a complete virion (i.e. it cannot replicate unless the host cell is co-infected by HBV).
186
Explain the structure and the mode of pathogenicity of prions.
Prions are infectious proteins that contain no nucleic acid (have no genome).
Known to cause disease only in animals.
Collectively, animal prion diseases are known as transmissible spongiform encephalopathies.
Infectious prion is in fact a faulty protein.
All mammal cells contain a gene that encodes native form of prion protein (PrPc) that is found in healthy individuals. PrPc is required for proper function of nervous system.
In prion victims, sometimes due to a genetic mutation or in many cases completely sporadically a misfolded type of PrPc called PrPSc (=PrP Scrapie) appears.
Misfolded proteins aggregate and form insoluble protein plaques that interfere with normal cell function.
187
Explain the role of non-pathogenic prions in humans.
A human protein called MAVS can convert into a prion-like structure in cells that become infected by virus. The production of this prion-like structure triggers interferon production in response to viruses and helps the immune system defend against thes? virus. Prion-like MAVS eventually kill the cell and prevents the virus from hijacking the cell’s molecular machinery for reproduction.
188
Which of the following is not a bacteria?
a) anthrax
b) diptheria
c) tuberculosis
d) rabies
rabies - its a virus
189
Which of the following is not a virus?
a) Ebola
b) Mumps
c) Shingles
d) Lyme disease
d) Lyme disease, it is caused by bacteria
190
Which of the following bacteria form endospores (select all that apply)
a) anthrax
b) C. difficile
c) Neisseria gonorrhoeae
d) Lyme disease
e) tetanus
anthrax, c. difficile, tetanus
191
Which of the following viruses has an envelope (select all that apply):
a) COVID-19
b) Ebola
c) HPV
d) Measles
e) Mumps
- COVID-19, Measles, Mumps
192
Which of the following is an unenveloped virus?
a) Zika virus
b) Ebola
c) Norovirus
d) Measles
e) Mumps
c) Norovirus
193
Which of the following is an non-enveloped virus:
a) Hepatitis C
b) Influenza
c) shigles
d) HPV
e) SARS
d) HPV
