MCB Exam 4 – Flashcards

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question
T/F: Most viruses are smaller than 0.45 nm, so are detected by electron microscopy.
answer
True
question
______________ is the inactive form of a virus. Once inside host it becomes active.
answer
Virion
question
What are the general virus characteristics?
answer

1. Sub-Microscopic

2. Obligate intracellular parasite

3. Host specificity

4. Needs host 4 energy n protein synthesis

 

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List the components that make up the virus structure.
answer

1. Nucleic acid

2. Capsid

3. Envelope

4. Spikes

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T/F:  Not all viruses have to have nucleic acids.
answer
False; all must have it!
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What is the function of the virus capsid?
answer

1. Protects DNA/RNA against damage

2. Involved in recognizing the host surface

3. Facilitates nucleic acid penetration

 

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What 2 structures must all virus have?
answer

Nucleic acids

Capsids

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What are virus envelops composed of?
answer
Host lipids and viral proteins
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What are virus spikes used for?
answer
Recognition and attachment to host
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What types of infection can occur with virus?
answer

1. Lytic = kills host

2. Persistant = small amounts of virus, host lives

3. Transforming = changes genetics, causes cancer

4. Latent = hides in host, no effect on host

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What are some of the ways the virus damages the host?
answer

1. Cell lysis

2. Cell transformation can lead to cancer

3. Produces toxic products

4. Alters host structure such as nuclear or cytoplasm

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What is the major virulence factor for viruses?
answer
The presence of the virus in the cell
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What are some ways that viruses can entry into host tissues?
answer

1. Directly by trauma or insect bite

2. Thru mucous membranes of the resp. tract or alimentary tract.

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Where is the most common entry site for viruses?
answer
Respiratory tract
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Define viremia
answer
When the virus reaches the blood system
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What are some of the reasons why viruses are able to grow inside hosts?
answer

1. Fast action

2. Adapts to host biochemical conditions

3. Able to resist host defense mechanisms

question
Describe the virus replication cycle.
answer

1. Attachment

2. Penetration

3. Un coating

4. Provision of energy

5. synthesis of Low MW compounds

6. Nucleic acid and protein synthesis

7. Assembly

8. Release

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What are some ways the virus evades the immune responses of the host?
answer

1. Inhibits the MHC I restricted Ag Presentation so no CD8 response

2. Inhibits MHC II restricted Ag presentation so no Ab, or Ag memory

3. Downregulates CD4 (T-helper cells)

4. Inhibits NK cell lysis

5. Intereferes with apoptosis

6. Evasion of humoral immunity

7. Inhibits cytokine action

 

question
List the different types of virus-cell interactions.
answer

1. Permissive or productive infection

2. Abortive or non-productive

3. Persistent

4. latent

5. Cytopathic effects (CPE)

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During permissive (productive) infection, the virus is produced and some cells are infected due to _____________.
answer
Receptors
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This type of virus-cell interaction leads to entry of the virus but no further expression occurs after a few genes are turned on.
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Abortive or nonproductive infection
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Which virus-cell interaction leads to the production of few viruses from few cells.  Most the cells are infected but they do not die.
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Permissive
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During this virus-cell interaction, the virus does not produce itself. Rather it hides within the host.
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Laten infection
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The virus-cell interaction that you can visually see under the microscope are CPEs.  What things can you see?
answer

1. Plaque formation in phage

2. Nuclear/cytoplasm enlargement

3. Nucleus changes

4. Cell fusion, syncytia formation

5. Lysosomes leaking

6. Viral budding, fibroblast

7. Changes in membranes

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What are the stages of the One - Step Growth cycle of the virus?
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1. Attach/adsorb to the cell

2. Penetration by fusion or endocytosis

3. Eclipse period

4. Rise = virus particles are detectable

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What is the Eclipse period of the One-Step Growth cycle of a virus?
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A phase in the proliferation of viral particles during which the virus cannot be detected in the host.  Penetration, uncoating, and synthesis occurs here.
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Define receptor mediated endocytosis.
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Once the virus is inside it attaches to a clathrin coated pit and forms a coated vesicle. It now requires a low pH to cause fusion of virus to endosome and uncoats to release the virus.
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T/F: Some viruses use cellular transcriptase and some use viral transcriptase.
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True
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Define viral syndrome. And give some examples.
answer

It is the pathogenic manifestations of a viral infection.

 

1. Flu like and systemic symptoms

2. Infection of the eye, oral, resp. tract

3. Gastroenteritis

4. Hepatitis

5. STDs

6. Hemorrhagic fevers

 

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What is the difference between cytopathology and immunopathology? 
answer

Cytopathology = Branch of pathology that studies and diagnoses diseases on the cellular level.

 

Immunopathology = Branch of medication that deals with the immune response associated w/the disease.  It includes the study of  the pathology of an organism, organ system, or disease w/ respect to the immunity/response.

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T/F: Rubella is caused by cytopathology.
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False; it is not cytopathic (CPE) so the infection does not end in cell lysis.
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How many different types of Hepatitis are there?  Which is considered to be Serum Hepatitis? What about Infectious hepatitis?
answer

A = Infectious Hepatitis

B = Serum Hepatitis

C

D

E

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These forms of Hepatitis are transmitted via percutaneous and permucosal.
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Type B, C and D
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These forms of Hepatitis is transmitted via fecal-oral route.
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A and E
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Which types of Hepatitis virus can lead to a chronic infection?
answer
B, C, and D
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Out of all the Hepatitis types, which is ones  do not have a vaccine available to it?
answer
Hepatitis C and E
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Which types of Hepatitis are associated with liver cancer?
answer
Hep. B and C
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This type of Hepatitis has a reverse transcriptase, DNA Poly. and RNAse H.  Also has ds and ss DNA and is in an enveloped icosahedron.
answer
Hep. B
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What are the modes of transmission for Hep. B?
answer

1. Sexual

2. Parenteral injecting

3. Perinatal

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Where is the [M+] of Hep. B the highest in the body?
answer
In blood, serum, wound exudates
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How can you prevent Hep. B?
answer

1. Prevent perinatal HBV transmission

2. Routine vaccines for all infants

3. Vaccinate

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Hep. C is in the _______________ family and has _________________ genome.
answer

Flaviviridae

+ss RNA

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How is Hep. C transmitted?
answer

1. Blood transfusions

2. IV drug users

3. Sex

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T/F: Only Hep. B is associated with liver cancer.
answer
False; Hep. B and C are associated with liver cancer
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What does Percutaneous and permucosal mean? Both Hep. B and C undergo this type of route of transmission.
answer

Percutaneous

1. Injecting drug use

2. Transfusion

3. Contaminated equipment

4. Needlestick

5. Clotting factors b4 viral inactivation

 

Permucosal

1. Perinatal

2. Sexually

question
Which route of transmission of Hep. C is the most common?
answer
Injection from drug users
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What are some nosocmial transmission of Hep. C?
answer

1. Contaminated equipment

2. Unsfae injection practices such as multiple dose medication vials

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When does perinatal transmission of Hep. C occur?
answer

Only when women HCV-RNA positive at delivery

 

(higher incidence in HIV women)

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T/F: Men to men is the more effiecient sexual transmission of Hep. C.
answer
False; male to female transmissio more efficient.  (indicative of sexual transmission)
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Which type of transmission of Hep. C accounts for 15-20% of acute and chronic infections in the U.S.  Also serves as a large chronic reservoir that provides hihger risk.
answer
Sexually transmitted
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Can household transmission of Hep. C occur? If so provide an example how?
answer
Yes, it can.  Sharing contaminated razors, toothbrushes, etc.
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How can you prevent Hep. C?
answer

1. Avoid direct exposure to blood

2. Cover cuts and sores on skin

3. Do not share items that may have blood on them

4. Do not donate blood, body organs, etc

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T/F: Hep. C can be transmitted by kissing.
answer
False; not spread by kissing, hugging, sneezing, coughing, sharing utensils
question
What are some ways to prevent sexual transmission of Hep. C?
answer

1. Use condoms

2. Limit # of partners

3. Get vaccinated against Hep. B

 

question
What can remove the envelope of Hep. B?
answer
Alcohol
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Out of all the Hep. types, which one is considered to be a retrovirus?
answer

Hep. B

It has reverse transcriptase

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Provide an example of a contaminated equipment and unsafe injection practice that contribute to the nosocomial transmission of Hep. C.
answer

Contaminated equip = Hemodialysis

 

Unsafe injection = plasmapheresis

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What 2 drugs when co-administered together help to treat Hep. C?
answer
Interferon and Ribavirin
question
What are important features of Hep C transmission via injecting drug use?
answer

1. Hihgly efficient amoung injection drug users

2. Rapidly acquired after initiation

3. 4x more common then HIV

5. Prevalence 60-90% after 5 years

question
Ribavirin is a analogue of ___________, with an incomplete base ring and an available 3'-OH grp.
answer
Guanosine
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What are the sites of activity for Ribavirin?
answer

1. Inhibits nucleoside biosynthesis

2. Inhibits capping of mRNA

3. Inhibits RNA Poly.

question
Which Hep. (B or C) has more cases of symptomatic infections?; Which has the most cases of death from chronic liver disease?
answer

Sympt = B (70K-160K; vs 3K- 54K)

;

Liver = C (8K-10K vs 5K-6K)

question
Describe the Herpes Virus structure.
answer

1. Enveloped icosahedral capsid 100 nm

2. 9 Glycoproteins

3. 30 structural proteins, but codes for 120

4. Tegument is amorphous

5. No common family antigen

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What are the 3 subfamilies of Herpesviridae?
answer

1. Alphaherpsesvirinae

2. Betaherpesvirinae

3. Gammaherpesvirinae

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Subfamily Alphaherpresvirinae include which 2 genus? What;virus does each genus include?
answer

1. Genus Simplex virus = HSV1 and 2, B virus

2. Genus Varicella virus = varicella-zoster virus (chicken pox)

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The subfamily Betaherpesvirinae includes these 2 genus?
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Genus Cytomegalovirus

Genus Roseolovirus

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What genus does the human herpes 6 and 7 belong to?
answer
Genus Roseolovirus
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Which subfamily of Herpres includes the genus Lymphocyrptovirus? And is associated with the Epstein-Barr virus?
answer
Subfamily Gammaherpesvirus
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The herpes virus had ___________________ DNA and naked DNA is ____________.
answer

Double stranded linear

infectious

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AlphaHerpes is _____________-tropic

BetaHerpes is ________________ tropic

Gammaherpes is ______________-tropic

answer

Neuro

Salivary gland

Lympho

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Describe the multiplication cycle of the Herpes virus.
answer

1. Attachment - glycoproteins on viral envelope fuses with cell P.M.

2. Penetration - direct or endocytosis

3. Envelopes are acquired at inner nuclear membrane

4. Virions are released by reverse phagocytosis

5. Cell is not killed, but the functions are taken over by the virus

question
When does latency of the Herpes virus occur?
answer
With persistant infected cells in which no infectious virus is formed because the multiplication cycle is stopped at some stage.
question
What are some characteristics of;HSV1?
answer

1. Fever blisters

2. Occurs early in life

3. Primary infection is 8-10 days

4. Latent infection is asymptomatic

;

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In HSV1 where does the viral DNA reside?
answer
In the sensory ganglia
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When do recurrent infections occur in HSV1?
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When the virus replicates and travels down the nerve fiber to infect epithelial cells.
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HSV2 is sexually transmitted. Where does the virus reside during latency?
answer

In the nerves of the lower back

(sacral plexus)

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When does recurrent infections occur in HSV2?
answer
5 or more times per year
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T/F: Prego women cannot transmit HSV2 during childbirth.
answer
False, they can
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List the viral syndromes caused by HSV1.
answer

1. Encephalitis

2. Keatoconjunctivitis

3. Pharyngitis

4. Esophaitis

5. Gladiatorum

6. Oral

7. Genital

8. Whitlow

question
List the viral syndromes caused by HSV2.
answer

1. Meningitis

2. Oral

3. Pharyngitis

4. Genital

5. Perianal

6. Whitlow

question
When it comes to the brain, HSV1 causes ________________whereas HSV2 causes ____________________.
answer

Encephalitis

Meningitis

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What are some major characteristics of the Varicella-zoster virus?
answer

1. Spread by resp. tract

2. Chicken pox = seasonal epidemics

3. Vesicular rash w/systemic infection

4. 2-2 1/2 wks long infection cycle

5. More severe in adults

6. Recurrent infection occurs

question
Recurrent infections of varicella-zoster virus is called ___________ and is localized to a ___________.
answer

Shingles

Specific nerve

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What are some major characteristics of Cytomeglavirus (CMV)?
answer

1. Infects and causes no obvious disease

2. Prego can abort fetus

3. Transmitted by saliva

4. Virus secreted in milk, saliva and semen

5. Major problem in immunosuppressed peeps

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A primary infection of the EBV causes ________________and ________% of people over 40 carry this virus.
answer

Mononucleosis

95%

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Which herpes virus family member causes cancer?
answer

HHV-8 is associated with Kaposi's sarcoma in AIDS patients

 

EBV is associated with Burkitt's lymphoma in AIDS patients and related w/ nasopharngeal carinoma in Africa

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What does Togaviridae mean?
answer
Covered virusees
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What are the 3 genera associated with Togaviridae? Which is the cause of german measles?
answer

1. Alphavirus

2. Rubivirus = causes Measles

3. Arteriviruses

question
Unlike other togavirus infections, Rubella causes a _____________ and can spread by ________.
answer

Respiratory illness

Aerosols

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T/F:; There is an insect vector with Rubella.
answer
False; none
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Why is Rubella dangerous to prego women?
answer
If mom does not have Ab to Rubella virus (from prior infection or vaccine), then virus can replicate in placenta and spread to fetal blood supply.
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What are some syndromes associated with congential infection of Rubella?
answer

1. Cataracts

2. Mental retardation

3. Deafness

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What are some important features of Paramyxoviridae family of viruses?
answer

1. Encased by a fragile lipid envelope

2. Nonsegmented (-) sensed ssRNA w/ 6-10 genes separated by noncoding termination, polyadenylation and initiation signals.

3. Replication occurs in the cytoplasm

;

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During viral replication of the family Paramyxovivridae, what does the virion attach to and how?
answer
Attaches to sialoglycoprotein or glycolipid receptor by the envelope glycoprotein
question
Which 2 membrane glycoproteins are key to the pathogenicity of all paramyxoviruses?
answer

1. H, HN or G = glycoproteins mediate cell attachment

2. F(fusion) protein;= has 3 functions

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What do the envelope glycoproteins H, HN stand for?
answer

H = Hemagglutinin

HN = Neuraminidase

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What are the 3 functions of the F (fusion) protein in all paramyxoviruses?
answer

1. Enables virus; to fuse to cell to form syncytia

2. Enable viral penetration by fusion of viral envelope w/ P.M.

3. Allows direct intercellular spread by cell to cell fusion (can now evade the bodys circulating Ab's, and allow transfer of infectious nucleocapsids to nearby cells)

question
What is the body's cellular immunity response to paramyxoviruses?
answer
Elicite a neutralizing Ab that inhibts adsorption of virus to cell receptors, thus inhibiting the infection.;
question
What occurs after 6 days with Measles?
answer
Virus spreads to all epithelial surfaces from the local blood vessels. (Viremia)
question
What contributes to the respiratory damage, fever and early symptoms seen with Measles?
answer
The immune system
question
What immunity/vaccine is there for Measles?
answer

1. Natural immunity against reinfection is effective

2. Passive immunization for the unimmunized (administer IgG)

3. Live vaccine

question
T/F:; Severity of measles is affected by young age, low socioeconomic status and malnutrition.
answer
True
question
List some complications that can occur with Measles.
answer

1. Subacute Sclerosing Panencephalitis

2. Subacute Measles Encephalitis

3. Acute Postinfectious Measles Encephalitis

question
Why is Subacute Scelrosing Panencephalitis (comp. of Measles) fatal?
answer
Manifests years after acute disease and fatal because of the slow spread of the virus into the brain.
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Why does Subacute Measles Encephalitis occur only in immunocompromised children?
answer
Becuase there bodies fail to eliminate virus-infected cells as the body lack cytotoxic T cells. (CD8)
question
Out of the 3 Measles complications that can occur, which is the most dangerous affecting 1 in 1000 older children. With a fatality of 15%.?
answer
Acute Postinfectious Measles Encephalitis
question
How are Mumps transmitted?
answer
By saliva or other respiratory fluids
question
What are some clinical features of Mumps?
answer

1. Distorted face

2. Edematous enlargement of the salivary glands

3. Infants often asymptomatic or as a resp. infection.

question
What complications can occur with Mumps?
answer
Mumps Encephalitis that can result in unilateral nerve deafness
question
_____________________ provides protective levels of the Ab by a single injection for at least 90% of those injected over a 20 yr period.; This decreased Mumps by 98%.
answer
MMR vaccine
question
What are the common features of families in the order Mononegavirales?
answer

1. Non-segmented, (-) sensed ssRNA

2. Helical nucleocapsid

3. Virion associated RNA-dependent RNA Poly

4. Similar gene order

5. Single 3' promoter

question
Which families are classified within the order Mononegavirales; which means they have common features of it.
answer

Filoviridae = Ebola

Paramyxoviridae = Measles, mumps

Rhabdoviridae = Rabies

question
What is some important features of the rabies virus?
answer

1. Can infect all warm blooded animals

2. Causes acute, contagious infection of the CNS

3. 100% fatal once symptoms show

4. Occurs worldwide except Hawaii, Japan, Great Britian and smaller islands

question
What are the principles rabies hosts today?
answer
Wild carnivores and bats infected with several virus variants
question
What are the vectors of transmission of the rabies virus?
answer

1. Bite/scratch of an infected animal (99% of cases worldwide)

2. Aerosol transmission from a bat

3. Tissue transplants from infected human (eyes)

question
T/F:  There is no viremia with the rabies virus.
answer
True
question
What is the course action of the rabies virus in humans?
answer

1. Enters vody and travels w/in neurons to the CNS

2. Causes encephalitis in the brain

3. Virus travels down the nerves and multiplies in many diff. organs

 

question
Which glands are the most important in the spread of the rabies virus from animal to humans?
answer
Salivary glands
question
What are some symptoms of Rabies?
answer

1. Early = nonspecific includes fever, headache, tiredness, etc

2. Progesses = Insomnia, anxiety, confusion, paralysis, hallucinations, hypersalivation, hydrophobia, hard to swallow

3. Late = Delirium, coma, Death

question
Which is the most definitive means of dignosis of Rabies?
answer
Virus cultivation
question
What vaccines are available for Rabies?
answer

1. Preexposure Prophylaxis

2. Postexposure Prophylaxis

question
Who should get the preexposure prophalyaxis for Rabies?
answer
Labworkers, vets, wildlife officers, animal handlers (people at high risk)
question
Preexposure prophylaxis for Rabies is an ____________ immunization with cell culture vaccine.
answer
Active
question
Which human disease is the only one that can be prevented by postexposure vaccination?
answer
Rabies
question
How many does of HDCV should be given for PEP of Rabies and prompt administration of what?
answer

5 doses

Admin Rabies Immune Globulin

question
________% mortality if treatment is given before onset of symptoms associated with Rabies virus.
answer
0%
question
What non-pharmacological treatment seems to reduce the spread of the Rabies virus.
answer
Thorough wound cleansing
question
What family does the Rotavirus belong to?
answer
Family Reoviridae
question
What are some important features of the Rotavirus?
answer

1. Wheel shaped, 70 nm

2. 2 concentric icosahedral capsids surrounding an inner core

3. dsRNA, 11 segments each coding for a viral protein

4. Non-eveloped

question
Why is the Rotavirus hard to make a vaccine for?
answer

It has 6 serogroups (A-F)

 

Group A is the most common in humans

question
What is the pathogenesis of the Rotavirus?
answer

1. Infects intestinal cells and kills them

2. Initial infection most severe

3. Absorptive surface of intestine is reduced

4. Fluid accumulation in lumen = diarrhea

5. Disease is self limiting

6. Dehydration problems

question
Which Ig is protective against Rotavirus?
answer
IgA in colostrum (breast milk)
question
A Rotavirus infection stimulates which Ig's?
answer

Secretory IgA

Neutralizing IgG

question
T/F: Maternal IgG is protective against Rotavirus.
answer
False; no protection
question
What is the route of transmission for Rotavirus?
answer

Fecal-oral

(highly contagious)

;

Can survive for hrs on hands and days on surfaces!

question
What are some clinical features of the Rotavirus?
answer

1. 1-3 day incubation period

2. May be asymptomatic

3. Mild to severe

4. Death due to dehydration and electrolyte loss

5. Fever, vomitting, watery diarrhea

6. Lasts 3-9 days

question
What is the common treatment for Rotavirus?
answer

Oral Rehydration - glucose, H2O, electrolytes

If severe, IV fluid replacement

question
What is the most common cause of gastroenteritis in children?
answer
Group A Rotavirus
question
How can you prevent Rotavirus?
answer

1. Good hygiene

2. Chemical disinfections

3. Breast feed newborns

4. Vaccinations*

question
What is the problem with the vaccine RotaShield for Rotavirus?
answer
Blocks the intestine (intussusception)
question
This vaccine is 98% protective against severe Rotavirus gastroenterisits.; It is a live oral vaccine.
answer
RotaTeq Vaccine
question
What 3 syndromes can the Influenza virus infection cause?
answer

1. Uncomplicated Rhinotracheitis

2. Respirtatory viral infection followed by bacterial pneumonia

3. Viral pneumonia

question
What are some major characteristics of the flu virus?
answer

1. Higher death in young and old (decline in cellular immunity)

2. Binds to clarithin coated pit--forms a coated vesicle

3. Needs a low pH to cause fusion to endosome and uncoat

4. RNA replication occurs in cytoplasm then to nucleus

question
What is the mechanism of action of Amantadine and Rimantadine to treat Influenza virus?
answer

1. Ion channel blockers that inhibit the replication of influenza virus by targeting M2 protein

2. Block acidifications of endosomes which inhibits the fusion

3. Since no fusion, release of viral RNA is prevented 

question
What is the mechanism of action of Tamiflu against Influenza virus?
answer
It is a neuramindase inhibitor designed to attack the structures of the Influenza viruses A and B, preventing the spread of the virus w/in the body.
question
What are some general characteristics of Piconaviruses?
answer

1. Small ~ 30nm

2. Naked icosahedral = Infectious

3. ssRNA

4. (+) sensed

5. Replication occurs in cytoplasm

6. Can go directly into cell and be translated

question
What are some important features of enteroviruses?
answer

1. Stable at pH 3 so can survive passage thru stomach

2. Spreads by fecal oral route

3. Multiplies in cytoplasm

4. Produces a large precursor protein that can undergo post tranlational cleavage

5. Cause variety of diseases

question
What is ICAM-1?
answer
Intracellular Adhesion Molecule-1
question
What is ICAM-1 role in virus attachment to the host?
answer
It is a specific cellular receptor that the Rhinovirus family attaches to.
question
What is the difference btwn primary and secondary viremia?
answer

Primary = initial spread of virus in the blood from the the first site of infection

 

Secondary = Primary viremia that now affects  organs such as the skin, brain, muscle, liver, & meninges

question
What happens during Poliovirus replication?
answer

1. Adsorption to specific receptors

2. Internalization in vesicles

3. Lowering of the pH in the vesicles

4. Exposure of Hydrophobic grps on the virus

question
List the 4 stages of polio virus infections.
answer

1. Alimentary phase

2. Lymphatic phase

3. Viremic phase

4. Neurological phase

question
What is a major illness of poliovirus infection progression?
answer

Meningitis (stiffness of neck or back)

Can lead to paralysis

question
What is IPV? OPV?
answer

Inactivated Polio Vaccine

Oral Polio Vaccine

question
What was used to the kill the polio virus to use in the inactivated polio vaccine?
answer
Formaldehyde
question
Which one (IPV or OPV) does not produce nasal and duodenal IgA protection?
answer
IPV
question
What is Post-Polio Syndrome?
answer

Peeps who survived polio show muscular weakness and paralysis many yrs after infection and recovery.

 

question
How does Post-Polio Syndrome develop?
answer

Caused by death of individual nerve terminals in the motor units that remain after the initial polio attack. 

Maybe due to possible deterioration of nerves that are required to function for damanged nerves. (degeneration of motor neurons)

question
Which type of meningitis is more common?
answer
Viral
question
List the viruses that cause viral meningitis.
answer

1. Measles

2. Mumps

3. Enterviruses (Polio, Cox B and Cox A7/9)

4. HSV

question
T/F:  Viral Meningitis is more severe than bacterial and recovery is almost none.
answer
False; recovery is almost always complete and is less severe. (the above describes Bacterial)
question
How is Viral Meningitis spread?
answer
By coughing, sneezing and poor hygiene
question
Can you use antibiotics for viral meningitis treatment?
answer
No
question
Is there a cure for Post-Polio Syndrome?
answer
No, can treat the symptoms such as muscle weakness
question
By the end of 2007, how many people had HIV? How many died?
answer

33 million had it

2 million died from it

question
 What are the clad, groups, and subtypes of HIV?
answer

Groups=

 M (Major)

 N (Non-O/ Non-M)

O (Outlier)

 

Clads = A, B, C, D, H, G, J, K

 

Subtypes = look at figure

question
How can HIV be transmitted?
answer

1. Sex

2. Inoculation of infected blood/blood products

3. Mother to child

question
HIV enters via mucosal linings during sexual contact, the first cells to become infected are ___________________. 
answer
Mucosal Dendritic cells (MDC)
question
Can you transmit HIV during nursing, if it is infected milk?
answer

Yes

Transmission can occur before, during or after birth

question
What is the likelihood of infection after a single exposure for the 3 routes of transmission of HIV?
answer

Sex = 0.01-1.0%

Blood Transfusion = >90%

Mom = 12-50%

question
Globaly, which route of transmission has the highest frequency although it is the least efficient route of transmission?
answer

Sexual contact.

Likihood after 1st exposure = 0.1-1%, but globaly accounts for 65-80 (73%) % of all cases

question
Which route of HIV transmission is the most effective?
answer
Blood transfusion. >90% likelihood of infection after single exposure
question
Which type of heterosexual transmission is the greatest?
answer
2x-5x risk from male:female>> female:male
question
What are some features of the HIV structure?
answer

1. Reverse transcritpase that converts ssRNA to dsDNA

2. Has integrase that allows it genome to get into host DNA

3. Viral envelope proteins

4. Has a viral core w/proteins (M protein, Capsid, Nucleoprotein)

5. Accessory proteins

question
What immune response occurs during the primary infection, clinical latency, Symptomatic stage of an HIV infection?
answer

Primary = Slight increase in the # of CD8+ T cells  in wk 6, but returns back down by wk 9.

CD4+ T cells decrease

Anti-gp120 dramatically increases from 0.

 

Clinical = CD8, CD4 and Anti-gp stay fairly the same, hence the latency. This occurs for ~ 6yrs

 

Symptomatic = Slight decrease in Anti-gp, Decrease in 1/2 # of CD8

Dramatic decline in CD4 in 2 yrs. By year 8 nearly 0 CD4 T cells. This is when AIDs will develop

question
After how many years of HIV infection, will AIDs develop in? What is nearly 0?
answer

After 8 yrs

CD4 T cells are nearly 0 at this time.

question
What is the pathogenesis of HIV?
answer

1. High turnover of HIV and infected CD4 T cell loads

2. Persistant Immune activation

3. Destruction of host immune system

question
What is persistant immune activation that occurs with HIV infection?
answer
Exhaustion and death of immune cells
question
What 4 symptoms of an acute HIV infection did he say to remember?
answer

1. Fever

2. Lymphadenopathy (enlarged lympth nodes)

3. Pharyngitis

4. Rash

question
During which clinical stage of HIV, has the highest plasma vRNA, Infectious particles, and infected PBMC?
answer

During the Acute infection

vRNA = 5 x 10^6

IP = 2,500

HIV-PBMC = >30,000

question
According to the CDC, a CD4+ T amount of < _____________ is classified as having AIDs.
answer
400
question
Describe the replication cycle for HIV.
answer

1. Adsorption to specific receptor

2. Penetration

3. Reverse transcriptase

4. vRNA transit

5. Integration into host DNA

6. Transcription

7. Transcript processsing

8. Translation/ Post translational processing

9. Capsid assembly/ budding

10. Capsid processing

question
Which steps of the HIV replication cycle can therapy work on to prevent the disease?
answer

1. Antibodies to prevent attachment

2. Fusion Protein inhibitor

3. RT Inhibitors, so cant make viral DNA

4. Integrase inhibitor so cant incorportate viral DNA into host DNA

5. Protease inhibitors so no posst translational processing

6. Zinc finger inhibitors to stop capsid assembly and processing

question
What is important about Anti-HIV nucleoside Analogs?
answer
They look similar to the nucleotides so they get incorporated into the DNA, but they dont function properly.  They prevent further elongation of the vDNA.
question
How do Non-nucleoside reverse transcriptase inhibitors work?
answer
Directly bind to the enzyme and interefers with the enzyme functions. Cant convert to viral dsDNA.
question
What is HAART?
answer

Highly Active Anti-Retroviral Therapy

 

Many anti-HIV drugs to treat HIV+ peeps.

Usually includes 1 NS Analog, 1 protease inhibitor and a non-nucleoside RT inhbitor or another NS analog

question
What precursor does viral protease create? What things arise from this precursor?
answer

Gag-Pol precursor

 

Capsid

Matrix

Nucleoprotein

Protease

RT

Integrase

question
What precursor arises from a cellular protease during HIV post translational processing?  Then what things can that precursor make?
answer

Env Precursor

 

Surface Env

Transmembrane

question
What do HIV protease inhibitors do?
answer
They prevent the HIV protease from cleaving the Gag-Pol precusor polyproteins into the individual viral structural proteins (capsid, matrix, nucleoprotein) and viral enzymes (RT, PR, IN)
question
What evaluations should be performed before starting treatement for HIV?
answer

1. Complete history and physical

2. CBC and chemistry profile (include transaminases and lipid)

3. CD4+ T cell count

4. Plasma HIV RNA measurement

question
What are the goals of HIV therapy?
answer

1. Maximal and durable suppression of virus load

2. Restoration or preservation of immunologic function

3. Improvement of quality of life

4. Reduction of HIV related morbidity and mortality

question
________________ uses probes to detect selected mutations that are known to confer drug resistance.
answer
Genotyping Resistance tests
question
___________________ measures the ability of the virus to grow in various concentrations of antiretroviral drugs.
answer
Phenotyping Resistance Tests
question
Why is it important to thoroughly evaluate an HIV patient before starting treatment?
answer

To decide whether or not treatment is needed.

If has a/symptomatic AIDs then treat.

 If Asymptomatic HIV then treatment should be offered (CD4 200-350).

If CD4 > 350 w/ RT-PCR > 55K then varies on treatment option. Now have >30% chance of getting AIDs.

If CD4 >350 but RT-PCR <55K then many would defer treatment. 

question
What are the major reasons for treatment failure in HIV patients?
answer

1. Resistance to drug = 70%

2. Low Drug [M+] at the viral replication site = 25%

3. Progressive decline of the immune system

question
What are causes of treatment regimen failure in HIV peeps?
answer

1. Patient factors such as age, co morbidities, etc

2. No compliance, miss clinical appts

3. Drug side effects and toxicity

4. Pharmacokinetics factors such as metabolism is fast, food/fasting, drug-drug interactions, etc

5. Potency of antiretroviral regimen

question

When does resistance occur for the following drugs that treat HIV?

NRTIs = Nucleoside RT Inhibitors

PIs = Protease inhibitors

NNRTs = Non nucleoside RT Inhibitors

answer

NRTIs = 6-12 months

PIs = 2-3 months

NNRTIs = days-weeks

question
When do you change an antiretroviral regimen for suspected drug failure?
answer

When 1 or more of the following occur:

1. Incomplete virologic response (failure to decrease HIV RNA)

2. Virologic rebound (Re-appearance of viremia after suppression. Shows resistance)

3. Immunologic failure (Persistant decline in CD4 T cell count)

4. Clinical failures (deterioration after 3 mo)

question
What is the global distribution of HIV-1 subtypes?
answer

Highest cases were in Sub-Saharan Africa (Accounts for 70% of all cases and about 58% of all women in Africa have it), SE Asia and South America.

In 2003, the global total = 40 million have it and 3 million deaths from it and 5 million new infections.

 

question
Why is it so difficult to develop a vaccine for HIV?
answer

RT is a high error prone enzyme that causes many mutations thus variations. 

The disease can spread by many different routes.

There are many different Clads and subtypes of HIV, hard to make 1 that fits all.  All have diff. properties/genes

question
What is important about AZT?
answer
It is a nucleoside analog. So it looks like regular NT but instead of 3'OH it has a N3.  This causes chain termination so no further elongation of viral DNA.
question
What is important about RT?
answer
It is the viruses reverse transcriptase.  This allows ssRNA to become dsDNA that way it can then go into the hosts DNA.
question
What stage of HIV infection has the highest titer of virus?
answer
Acute (Primary) infection
question
During which stage does persistant immune activation occur?
answer
During the Primary infection where your body is constantly trying to fight off the virus
question
What is cross resistance?
answer
If develop for resistance to 1 drug then become resistant to other drugs that have a similar mechanism of action (ex. if in same drug class)
question
Which HIV drugs has the highest frequency of cross resistance?
answer
NNRTI > PIs > NRTI
question
What is meant by Acute Fulminant Hepatitis?
answer
Acute liver failure
question
Which Hepatitis virus causes Fulminant Hepatitis?
answer

Hep B.

 

(I'm not too sure, Hep A has 100 deaths a yr from this and Hep D has 35 deaths a yr. But Hep B is 150 deaths a year).

question
Which herpes virus is more problematic for AIDS patients?
answer
Herpes Simplex
question
What are the 2 main routes by which enteroviruses may reach blood?
answer

1. Fecal oral route (ingested)

2. Respiratory

 

(I'm like 90% positive about this)

question
Once an enterovirus is in the blood, where does it go after that?
answer

Can go to the CNS and affect the brain.

Or can cause secondary viremia and affect other organs such as the skin, liver, muscle.

question
What is the % of people who previously had Polio will develop Post Polio Syndrome? And when do symptoms appear?
answer

1. 25-50% of people

2. Symptoms occur 15-30 yrs after the original infection

question
The highest number of Hep. C positive peeps are found among ____________ and _____________.
answer
Black and Hispanic
question
What are some features of fungi?
answer

1. Affected by Geography & environment ( with damp areas)

2. Associated w/ soil

3. Produce endospores for reproduction

4. Are usually inhaled

5. Recycle organics

6. Opportunistic

7. Major antibiotic producers

6.

question
Fungi can be divided into ______________ and _______________.
answer

Yeast

Mold

question
Yeasts are typically ____________ and reproduce by ____________. Give an example of one.
answer

Round/oval

Budding

 

Ex: Candida

question
Molds are composed of ____________ that grow _______________ and _____________ extensions.
answer

Hyphae

Branching

Longitudinal

question
Give an example of a mold.
answer
Aspergillus
question
T/F: Some fungi are dimorphic; both yeast and mold like
answer
True
question
T/F: Candida is part of the normal flora.
answer
True
question
What is responsible for one of the first manifestations of AIDs?
answer
Candida infections
question
What infections can Candida cause?
answer

1. Thrush

2. Yeast infection

3. Skin and Mucosal infections

question
Thrush is characterized by white pustules in the ___________ and _____________.
answer
Mouth and throat
question
Give an example of a dimorphic fungus.
answer
Histoplasma
question
Where does the fungus Histoplasma reside and how is it acquired?
answer

Resides inside macrophages and neutrophils.

 

Acquired by inhalation

question
Do antibiotics work against fungi?
answer
No.  Use Amphotericin B
question
________________ are molds and the causative agent of ringworm.
answer
Dermatophytes
question
If the dermatophytes primarily infects animals it is called ______________, if it affects only humans then it is called _________.
answer

Zoophilic

Antrhopophilic

question
Dermatophytosis tend to infect which kinds of sites?
answer

Scalp

Feet

Skin

Groin

question
This dermatophytes primarly affects the groin area and causes Jock itch.
answer
Tinea Cruris
question
Which dermatophyte causes ringworm in legs and trunks?
answer
Tenia Corporis
question
____________ causes ringworm of the scalp.
answer
Tinea Capatis
question
Which dermatophytes causes a fungal infection of the nails.
answer
Onychomycosis
question
Tenia Pedis is seen in young teens and is common in bathing facilities.  It affects ____________ and the main symptom is __________.
answer

Toes

Itching

question
How does the mold Aspergillus enter the body?
answer
Inhalation of spores. But can also enter thru traumatized skin
question
What are some features of Protozonal infections?
answer

1. Eukaryotic, unicellular

2. In 2 forms: cysts or trophoziote

3. Classified based on there locomation

4. Fecal-oral route

5. H2O borne also

6. Anaerobic

question
Trichomonas vaginalis is a _____________ parasite with no known cyst form.
answer
Flagellated
question
T/F: Men cannot get Trichomanas Vaginalis.
answer
False; they are also infected
question
The cell wall of fungis have _______________ which is a target for anti-fungal drugs.
answer
Ergosterol
question
Which form of a parasite is infectious? which is the growing form?
answer

Infectious = Cyst form

Growing = Trophozoite

question
What oral agent is used when scalp and nail infections dont respond to topical therapy?
answer
Griseofulvin
question
What is the significance of Metroniazide in treating anaerobic infections?
answer
It forms an "electron sink" and inhibits the anerobic respiration and the double helix structure
question
Which protozoan infection could be considered an STD?
answer
Scabies
question
What is Scabies?
answer
Highly contagious parasitic skin infection caused by mites that are host specific to humans and completes its entire life cycle on human skin.
question
What are important clinical features of infection by Histoplasmosis?
answer

1. Severe infections resemble ARDS

2. Causes large pulmonary lesions that become nodules = Histoplasmoma

3. Granuolmatosis and fibrosis that infects lymph nodes

4. If chronic have diseased upper lobes of lung

5. Progressive is usually fatal

6. Can infect choroid

7. African version selectively affects skin, soft tissues and bone not lungs.

question
Which body fluids have the lowest amount of Hep. B?
answer

Urine

Feces

Sweat

Tears

Breastmilk

question
Which body fluids have moderate amounts of Hep. B?
answer

Semen

Vaginal

Saliva

question
List some ways to prevent Scabies?
answer

1. Wash bedding in very hot water (125 F)

2. Avoid sex w/ infected peeps

3. Dry clean clothing

4. Vacuum living room

5. Dont share clothes/towels/bedding

6. Notify school

question
Malaria is caused by ______________, and use ________________ as there insect vector to transmit to humans.
answer

Plasmodium

Female Anopheles Mosquitoes

question
Which cycle in the mosquito is it when the protozoan turns into the cyst form?
answer
During the Sporogonic cycle
question
Once the cyst form of Malaria bites a human, what cycle does it enter and what organ does it affect?
answer

Enters the Exo-Erythrocytic Cycle

 

It affects the liver

question
What happens during the trophozoite form of Malaria?
answer
The protozoan is in the liver. It ruptures and leaves the liver to go to the RBCs.  The RBCs can then rupture and regenerate the protozoan.
question
During which stage of Malaria infection is responsible for clinical manifestations of the disease?
answer
Erythrocytic Cycle
question
_____________________ is the morphological form which develops in the mosquito salivary gland.  It is injected when the mosquito feeds.
answer
Sporozoite (cyst form)
question
What are the typical clinical manifestations of Malaria?
answer

1. Recurrent high fever

2. Chills

3. Headache

4. Anemia

5. Splenomegaly

6. Weakness

question
What can Malarial organism also cause, that will ultimately lead to death? Why does this occur?
answer

Can cause Splenomegaly.

The Red pulp of the spleen is the cemetary for RBC.  The spleen enlarges because it has alot of dead RBCs.

question
How many new infections of Malaria are there a yr and what is the best means of controlling mosquito pop.?
answer

600 million/yr

Use DDT

question
How many deaths per year are associated with Malaria?
answer
3 million
question
Which protozoan invades RBCs?
answer
Malaria
question
Which 2 protozoan infections are associated with HIV infection?
answer

1. Leishmaniasis

2. Malaria

question
Which protozoan infects Reticuloendothelial cells?
answer
Visceral Leishmaniasis
question
Which protozoan is the causative agent for Amoebiasis, and 100,000 deaths/yr?
answer
Entamoeba Histolytica
question
Which protozoan caused flask-shaped lesions in the colon and causes bloody diarrhea?
answer
Entamoeba Histolytica
question
What % of people w/E.Histolytica are asymptomatic?
answer
85-90%
question
How is E.Histolytica transmitted?
answer

Fecal-ral

Sexual

question
What are some important features of Giardiasis?
answer

1.  (4pairs of flagella) Flagellated protozoan parasite

2. 1 celled organism

3. Lack ER, Mito, GA and Lyso

4. Protective outer shell

5. Anaerobic

6. Aerotolerant

question
Cyst form of Giardia is ingested with contaminated water and food and is passed in ___________.
answer
Feces
question
What animal serves as a reservoir of Giardia?
answer
Beavers
question
________________ causes very distinct, smelly, greasy, frothy diarrhea.
answer
Giardia Lamblia
question
Which protozoan has a very low ID50 and cuases a diarrheal disease?
answer
Cryptosporidium parvum
question
How is Cryptosporidium spread?
answer

Fecal oral

Water/food borne

question
What are the 3 types of Cryptosporidiosis that can occur?
answer

Intestinal

Pulmonary

tracheal

question
How is Leishmaniasis transmitted?
answer
Via the bite of female sand flies
question
Which is the most severe form of Leishmaniasis and is related to HIV?
answer
Visceral Leishmaniasis (VL)
question
There is a _______% mortality rate in VL if untreated and __________% of adult cases are related to HIV.
answer

100%

25-75%

question
What is a possible outcome for G.Lamblia infection? And who is at risk for this disease?
answer
Found in day cares. Can lead to chornic symdrome of diarrhea that contributes to malabsorption and weight loss. (35-70%)
question
Which protozoans are capable of causing skin infections?
answer
Leishmaniasis and Scabies
question
Which protozoan can cause both a skin and systemic infection?
answer
Leishmaniasis
question
What are the signs and symptoms of Leishmaniasis infection?
answer

1. Persistent fevers, may cycle

2. Night sweats

3. Fatigue

4. Weakness

5. Appetite loss

6. Weight loss

question
What are the 3 basic principles of antimicrobial therapy?
answer

1. Selective toxicity (kill organism not man)

2. Reach the site of infection at inhibitory [M+]

3. Penetrate and bind to target (avoid inactivation and extrusion)

question
List the target sites/activities for Antibacterial agents (antibiotics).
answer

1. Cell wall synthesis (we lack this)

2. Protein synthesis (ribosomes)

3. Nucleic acid synthesis

4. Cell membrane function

question
What is murein?
answer
Means cell wall composed of 2 monomers NAG and NAM that is cross linked.
question
Which classes of antibiotics affect the cell wall synthesis?
answer

1. Clycoserine

2. Glycopeptides

3. Bacitracin

4. Beta lactams

question
What is the mechanism of action of Beta Lactam antibiotics?
answer
Penicillin Binding Proteins (PBPs) are enzymes involved with cross linking bacterial cell wall components.  Beta Lactams bind to them and inhibit the enzyme from catalyzing the cross link. 
question
What are the classes of antibiotics that target protein synthesis mechanism?
answer

1. Aminoglycosides

2. Tetracyclines

3. Chloramphenicol

question
List different Aminoglycosides.
answer

1. Gentamicin

2. Streptomycin

3. Amikacin

4. Neomycin

question
Penicillin is considered to be _________________ because it kills growing bacteria.
answer
Bacteriostatic
question
Why is it harder to achieve selective toxicity with drugs targeting viral diseases and eukaryotic diseases than prokaryotic?
answer
The cells of viral and eukaryotic diseases are similar to the host.  Targeting these cells can accidentally damage the host cells also. 
question
What is selective toxicity?
answer
Exploiting differences in structure/metabolism of pathogens and host cells in order to kill the microrganism and not the human host.
question
Most antibiotics acting upon the ribosome are ______________, but aminoglycosides are ____________.
answer

Bacteriostatic

Bactericidal

question
What are some general properties of Aminoglycosides?
answer

1. Treatment for severe sepsis

2. Needs O2 for entry into cells

3. Fat insoluble = not absored orally

4. Toxic to kidney and inner ear

question
What is the mechanism of action for Tetracyclines?
answer
Inhibits protein synthesis by preventing amino acyl transfer RNA from entering the A site on the ribosome.
question
How does Chloramphenicol inhibit protein synthesis?
answer

It has a nitrobenzene nucleus that blocks peptidyl transferase blocking the protein synthesis.

 

(Bacteriostatic)

question
What are some drugs that act on inhibiting precursor synthesis of nucleic acids?
answer

1. Trimtethoprim

2. Sulfonamides

question
_______________ is used as a DNA replication inhibitor because it affects _____________, so the bacteria is unable to 'pack' DNA into the cell.
answer

Quinolones

DNA gyrase

question
Which antimicrobial agent affects DNA-dependent RNA polymerase, thus blocks mRNA so no nucleic acid is made.
answer
Rifamycins
question
Which drugs affect cell membranes?
answer

1. Azoles = no synthesis of ergosterol

2. Polyenes (Amp.B) = binds to sterols and causes leakage of components then causes cell death.

question
What does Metronidazole do to DNA?
answer
When it is reduced it can bind to DNA, oxidize it and then cause strand breakage.  Works for anerobic infections.
question
How can resistance disseminate?
answer

1. Chromosomally mediated resistance= mutant selection

2. Plasmid mediated resistance = spread of ressitance plasmid

3. Plamid mediated resistance on transposon = spread of resistance gene

question
What is plasmid?
answer
Molecules of DNA which replicate independenly of the bacterial chromosomes.
question
What are some ways bacteria can make antibiotics ineffective?
answer

They can physically and chemically remove the drug.

 

1. Alter target = lowers affinity for antibacterial

2. Alter the uptake = pump drug out of cell

3. Drug inactivation = enzyemes that kill the antibacterial agent

question
How can humans prevent development of antibiotic resistance bacteria?
answer

1. Dont dispense antibiotics w/out Rx

2. Control misuse of antibiotics

3. Antibiotic policies

4. Surveillance of use coupled w/ monitoring emerging patterns of resistance

5. Control use in industry

question
Which organism is responsbile for stomach ulcers?
answer
H.Pylori
question
T/F:  H.Pylori and Strep. Mutans are not part of the normal flora.
answer
False; both are in normal flora
question
What are the virulence factors for H.Pylori?
answer

1. Flagella

2. Adhesins (attaches to stomach lining)

3. Urease enzyme (neutralizes acid so bacteria can grow)

question
How do you treat stomach ulcers?
answer
Lifestyle changes and acid reducers
question
What causes plaque and tooth decay?
answer
Strep. Mutans
question
How does Strep. Mutans soften enamel?
answer

Bacteria can turn sucrose into Glucan (polymer).

Glucan allows the formation of biofilm.

Biofilm covers bacteria and provides anaerobic growing conditions for bacteria.

Fermentation occurs w/ sucrose.

This decreases pH

Decreased ph softens enamel

question
T/F: Strep. Mutans have pilli for attachment.
answer
True
question
List viral infections for which a vaccine is available.
answer

1. Hep A and B

2. Influenza

3. Measles, Mumps, Rubella (MMR)

4. Polio

5. Rabies

6. Smallpox

7. Varicella-Zoster

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