Virology Flashcards

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1
Q

Of all the microorg, which is the smallest

A

Virus

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2
Q

Virus are obligate parasites . What does it mean

A

It means they need a host to survive. They can’t survive without a host

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3
Q

What is virus made up of

A

Nucleic acid and a protein coat

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4
Q

Characteristics of virus

A

They reproduce rapidly
Can’t reproduce without a host
They don’t have ribosomes so they can’t synthesize proteins
So they depend on the host’s ribosomes
They can’t produce energy so they depend on the host to get energy

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5
Q

Structure of the virus

A

From the outer portion :Envelope( made up of either lipid,protein,carbs)
Tergument
Capsid
Nucleic acid

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6
Q

Some virus produce enzymes. Give an example

A

HIV

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7
Q

Structure of virus

A

Spherical

Fillamentous

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8
Q

If a virus has an envelope made up of carbs and proteins what wil the name of the envelope be

A

Glycoprotein envelope

And it will surround the nucleocapsid

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9
Q

The projection on the outer layer of the virus are called? And what is their function

A

Spikes

They enable the virus to hook onto cells for attachment

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10
Q

Tergument is a protein that doesn’t have a fixed shape. True or false

A

True

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11
Q

Most proteins of the virus are found where

A

In the tergument

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12
Q

Antigen antibody test detects what in the virus

A

The protein in the virus

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13
Q

Function of the capsid

A

It gives the solid structure of the viruses and covers the nucleic acid and forms the nucleocapsid.
Inside the capsid is the nucleic acid so It protects the inner structure of the nucleic acid.
Enables virus to attach itself to the surface of the host and gain penetration into the host

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14
Q

Not all viruses have envelopes. Give an example

A

Ebola virus
Polio virus
HIV has envelope

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15
Q

Most viruses at which nucleic acid

A

RNA

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16
Q

With DNA, either they are double stranded or single stranded DNA and with RNA either they are double stranded or single stranded RNA true or false

A

True

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17
Q

Some RNA are positive strands and helps the virus replicate fast. How?

A

They can easily be converted into messenger RNA and then leads to protein translation

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18
Q

Some RNA are negative strands. What does it mean

A

They need another enzyme to convert the RNA into something for protein synthesis

Positive-sense viral RNA is similar to mRNA and thus can be immediately translated by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation.

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19
Q

What is reverse transcriptase

A

A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by certain viruses such as HIV and the hepatitis B virus

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20
Q

Name two other Structure of viruses based on nucleic acid and structural proteins

A

Viroids- have only nucleic acid but no structural protein
Prions- looks like virus but aren’t virus( they’re composed mainly of protein tightly integrated w a small nucleic acid molecule

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21
Q

Rabies virus is the only virus with a bullet shape true or false

A

True

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22
Q

What is the suffix of the family and genus of viruses

A

Viridae and genus is virus

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23
Q

Which properties of viruses help them to be classified

A

Genome properties: type of nucleic acid, size of genome in kilo based or kilo base pairs, segments
Morphology: sizes, shapes, type of capsid, symmetry
Physiochemical-pH, stability, there
Al stability, susceptibility to physical and chemical agents
Nature of the host- plant host or animal host
Antigenic properties
Biological properties- method of transmission, disease caused

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24
Q

Symmetry types of viruses

A

Helical o

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25
Q

Give two advantages of classification of viruses

A

Prompt identification of organisms for appropriate diagnosis and treatment
To understand how the organisms causes diseases ( the pathogenicity of the organism)

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26
Q

Name four sources of viral infections

A

Viruses don’t grow in every cell

  1. Saliva- rabies in dogs
  2. Faeces - virus multiplication in small intestine example enteroviruses (example,polio)
  3. Blood example HIV
  4. Urine example Lassa fever
  5. Body fluid example chicken pox
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27
Q

Name the processes by which viruses infect

A
  1. Primary replication
  2. Systemic Spread
  3. Secondary replication
  4. Cell tropism
  5. Cell death
  6. Immune response
  7. Viral clearance or resistance
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28
Q

Explain how virus infects

A
  1. When virus enters the body, they go into incubation period and multiply. 2.They start spreading thru the blood system. Then they go to specific organs of the body through the secondary lymph nodes. ( near the armpit)
    3.They replicate more in the lymph nodes then they move into the cells and they attacking the organs and the tissues
  2. Viruses affinity for specific body tissues( cell tropism) . Every virus has a receptor it can attach to to enter the host.
    When they enter the cytoplasm of the host, they shed off their protein coat cuz the Niclic acid will tell the host to make a copy of the viruses nucleic acid. Then when the copies are made, they put on the protein coat and then come out of the cell. If it’s an RNA virus it produces the mRNA and leads to the production of the proteins and the proteins come out with the protein coat
    5.They cause cells to die
    When this occurs, the immune system tries to attack the virus and clear it or overcome it. Then it spread into the systems and causes diseases
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29
Q

Roles of secretory bodies

A
  1. Cellular immune response : production of T cells

2. Humoral immune response :leads to the production of antibodies

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30
Q

Pathogenesis of viral infections

A

Ability of the virus to enter the host and cause disease
Infection is the ability of the virus to enter the host whether it causes an infection or not

Viral replication
Adsorption or attachment 
Entry or penetration 
Uncoating 
Transcription 
Synthesis of virus components 
Assembly
Release
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31
Q

When is a person said to be subclinical

A

Viral infections are not able to produce symptoms in the host

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32
Q

Why is the behavior of the virus receptor called lock and key

A

Example: polio virus can’t enter CD4 T cells cuz they don’t have a ligand or door for polio virus to enter to cause harm.

When virus has a specific receptor for the ligand or door on the target cell then it attaches to it

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33
Q

Diagnosis of viral infections

A

Find genome of virus using PCR(polymerase chain reaction)or detect the antibody being produced by the body as a result of the virus using ELISA or rapid test

34
Q

Treatment and importance of diagnosis of viral infections

A

Epidemiological information
Public health intervention
Discovery of drug resistance strain
Surveillance

35
Q

How is collection of specimen done

A

Culture virus or use PCR or antibody antigen detector

Virus is cultured using egg yolk

36
Q

What is the genus of Herpes viridae

A
Herpes- simplex viruses 1 and 2
Varicella-zoster viruses
Epstein-Barr virus
Human cytomegalovirus 
HHV 6,7,8
37
Q

Name characteristics of herpes

A

Has DNA nucleic acid
Have glycoprotein spikes
They are found in shape or icosahedral

38
Q

Heroes simplex one occurs in children between 1-5 years . Give three symptoms of it

A

Sore throat
Vesicular ulcerative lesions
Swollen gum is common

39
Q

Herpes simplex 2 is sexually transmitted true or false

A

True

40
Q

Lab diagnosis of herpes

A

Gemsa staining of scrapings
PCR to detect virus
Serology

41
Q

Human cytomegalovirus affects which people specifically and where and mode of transmission

A
Is usually in the blood
Affects infants 
Is found everywhere In the world 
Mode of transmission is by close contact 
Attach T cells and organs of the body
42
Q

Symptoms of cytomegalovirus

A

Fever headache
Elevates ALT and AST
Myagias

43
Q

Lab diagnosis of cytomegalovirus

A

PCR
Detect IgM antibody by ELISA
ISolation of virus from urine or saliva

44
Q

Retrovirus contains which genome

A

RNA but reverse transcribes into DNA on entering the host cells

45
Q

HIV 1 is a member of which genus and characteristics of it

A

Lentivirus genus
Is cylindrical shape
RNA genomes with core proteins such as gag, pol, envelope proteins and ancillary proteins tat,rev, Nef

46
Q

Difference between HIV 1 and hiv 2

A

HIv-1 has viral protein u which is an ancillary protein

HIV-2 has viral protein x

47
Q

HIV-1 is from which animal and hiv-2 is from which animal

A

Chimpanzee and monkey

48
Q

How many distinct groups of HIV-1 and subtypes of hiv-1

A

3 and 11

5 subtypes for hiv-2

49
Q

In Ghana which HIV subtype is common

A

A and D

50
Q

Differences between hiv-1 and hiv-2

A

HIV-1 - within 10 years you can die
HIV-2 you’ll last longer
HIV-1 mother to child transmission is higher
HIV-2 mother to child transmission is lower
HIV-1 plasma viral load is higher
HIV-2 plasma viral load is lower

Mortality rate is higher in hiv-1 than hiv-2

51
Q

What is viraemia

A

When Viruses are in the blood

52
Q

All you need to know about Adenoviruses

A

Transmission- respiratory and fecoral route
Causes bronchiolitis and pneumonia in children ( serotypes 1-7)
Gastroenteritis (serotypes 40-41)

In immunodeficiency people they can die out of it even tho it is usually self limiting for the gastroenteritis
If you also don’t keep them hydrated they can die out of it

53
Q

Which organisms affect pregnant women

A

Parvovirus
Listeria monocytogenes
Rotavirus- rubella

54
Q

What is arthralgia and how different is it from arthritis

A

It refers to pain in a joint and it is different cuz it’s a symptom and not a diagnosis while arthritis is a diagnosis and not a symptom

55
Q

What are the similarities between Hep A and E virus

A

Both transmitted by Fecal oral route

Both cause acute hepatitis only

56
Q

Hep A belongs to which family and hep R belongs to which family

A

Picornavirus and flaviviridae

57
Q

Similarities between hep B and C

A

Both transmitted thru blood transfusion or direct contact w infected blood
Both cause both acute and chronic infections, liver cirrhosis, hepatocellular cancer

58
Q

Hep D does not stand alone and is only possible to be seen with someone who already has hep B true or false

A

True

59
Q

What is the structure of hep B nucleoplasmid and genome

A

Nucleocapsid contains a single copy of partially double stranded circular DNA genome which is covalently linked to the viral reverse transcriptase at the 5’ end of the complete strand

60
Q

Hep A has a vaccine but it not routinely true or false

A

True

61
Q

Since hep B can be sexually transmitted by body fluids then which people usually get it

A

Travelers and homosexuals

62
Q

Which part of Hep B structure elicits antibodies

A

Envelope and core antigens

63
Q

The core antigen of hep B is not detected in the blood true or false

A

True

64
Q

Serology is the main method of hepatitis diagnosis true or false

A

True

65
Q

What is the importance of surface antigens, envelope antigens and core antigens

A

Surface antigen are what are checked for in hep B screening to see if you are infected.
Surface antibodies are checked to see if you are protected

Envelope antigens: show if the virus is replicating or not. If positive then you can easily infect people

Core antigens : are not detectable in the blood. Antibodies you produce against the core antigens show if you have been infected before

66
Q

IgM shows what and IgG shows what

A

IgM shows if you’re acutely infected or there’s been a recent infection
IgG shoes if you have a chronic infection

67
Q

What is the goal in treatment of hep B currently

A

To suppress viral replication

68
Q

What test is used to check for viral load and importance of checking for it

A

PCR
It shows which patients require treatment and which need to b monitored
Liver biopsy is also needed to determine this

69
Q

Drugs given to hep B patients who need it

A

Adefovir
Lamivudine
Tenofovir

70
Q

Hep C genome is .. while hep B genome is ..

A

RNA and DNA

71
Q

Unlike hep B, hep C is curable true or false

A

True

72
Q

If as an adult you get hep B, most cases are acute but it will be chronic for people who got it through mother to child transmission true or false

A

True

73
Q

In which bodily fluids is hep B virus high

A

Blood
Serum
Wound exudates

74
Q

Which body fluids is hep B virus moderate

A

Semen
Saliva
Vaginal fluid

75
Q

In which body fluid is hep B virus low or not detectable or you can’t get it if you come into contact with these

A
Urine
Faces
Sweat
Tears
Breast milk
76
Q

How many Clinical stages of HIV infection are there

A

4
Stage 1- asymptomatic
Stage 2-Herpes roster, weight loss,recurrent respiratory tract infections,Fungal nail infections (Tinea)
Stage3-severe weight loss,persistent oral candidiasis,pulmonary tuberculosis,severe bacterial infections
Stage4-oesophageal candidiasis,extra pulmonary TB,Extrapulmonary Cryptococcosis,disseminated mycosis (extra pulmonary histoplasmosis,coccidioidomycosis),invasive cervical carcinoma,symptomatic HIV associated nephropathy or cardiomyopathy,recurrent bacterial pneumonia

77
Q

Herpes nucleic acid structure is

A

Double stranded DNA

78
Q

How does HIV infect and establish itself in the host

A

HIV infects a type of white blood cell in the body’s immune system called a T-helper cell (also called a CD4 cell). These vital cells keep us healthy by fighting off infections and diseases. HIV cannot reproduce on its own. Instead, the virus attaches itself to a T-helper cell and fuses with it (joins together).

After HIV RNA is converted into DNA, HIV’s integrase enzyme attaches itself to the end of the proviral DNA strands and it is passed through the wall of the cell nucleus. Once the proviral DNA enters the cell nucleus, it binds to the host DNA and then the HIV DNA strand is inserted into the host cell DNA.

After HIV RNA is converted into DNA, HIV’s integrase enzyme attaches itself to the end of the proviral DNA strands and it is passed through the wall of the cell nucleus. Once the proviral DNA enters the cell nucleus, it binds to the host DNA and then the HIV DNA strand is inserted into the host cell DNA.

79
Q

What is viraemia

A

When Viruses are in the blood

80
Q

All you need to know about Adenoviruses

A

Transmission- respiratory and fecoral route
Causes bronchiolitis and pneumonia in children ( serotypes 1-7)
Gastroenteritis (serotypes 40-41)

In immunodeficiency people they can die out of it even tho it is usually self limiting for the gastroenteritis
If you also don’t keep them hydrated they can die out of it

81
Q

Which organisms affect pregnant women

A

Parvovirus
Listeria monocytogenes
Rotavirus- rubella