Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology - RA > Viral Infections > Flashcards

Viral Infections Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Viruses are what size?

A

20-300 nanometres, not visible on light microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Can viruses replicated independently?

A

No.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do viruses replicate?

A

Invade host cells and use their cellular machinery to replicate - intracellular parasites. They do not divide by binary fission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Examples of viruses?

A

Influenza, Common cold, Chickenpox (varicella), Herpes and HIV/AIDS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Viruses are easy/difficult to treat?

A

May be difficult.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The HIV/AIDS epidemic was caused by which virus?

A

Human retrovirus HIV.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Morbidity and mortality of HIV epidemic?

A

25 million died in epidemic and 33 million currently infected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Swine flu virus is called what?

A

H1N1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The current pandemic is?

A

Swine flu.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Is swine flu easily transmissible?

A

Yes but not highly pathogenic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a virus?

A

A piece of genetic information in a protein coat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How have viruses evolved to transfer genetic information between cells and protect themselves?

A

Have developed a closed shell to protect nucleic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Capsids are composed of repeating protein units - same or many - what are these called?

A

Protomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The protomers must be arranged how?

A

Platonic structure - A simple regular structure that utilises bonds between same pairs of chemical groups.
Any of the five regular polyhedrons – solids with regular polygon faces and the same number of faces meeting at each corner – that are possible in three dimensions. They are the tetrahedron (a pyramid with triangular faces), the octahedron (an eight-sided figure with triangular faces), the dodecahedron (a 12-sided figure with pentagonal faces), the icosahedron (a 20-sided figure with triangular faces), and the hexahedron or cube.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why can’t the coat have hexagonal faces?

A

They would meet at 360 degrees and be planar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which is the only closed shell structure that can be made with identical protomers?

A

The icosahedron - most efficient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Another structure for the capsid is?

A

Helix - protomers laid end to end with identical bonds form a ribbon like structure and wrap around axis. Length determined by length of nucleic acid. Diameter determined by characteristics of protomers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Some viruses also have a…

A

fatty lipid envelope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Four types of structure are..

A

Naked icosahedron, enveloped icosahedron, naked helical and enveloped helical?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why are bonds looser in enveloped helical structures?

A

To wind around inside.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How are viruses classified?

A

Presence or absence of envelope.
Nucleic acid type: DNA or RNA.
Capsid symmetry: helical, icosahedral or complex.
Number of strands of nucleic acid and their construction (single or double stranded, linear, circular, segmented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Yellow fever is what type of infection and what are the symptoms and outcomes? How is it transmitted?

A

Acute haemmorhagic viral infection. Fever, vomiting, bleeding - recovery or death. Transmitted by mosquitoes rather than fomites.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Previous prevention of yellow fever and current?

A

Previous: infected people slept in nets.
Current: vaccines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How are viruses studied?

A

Electron microscopes to see viruses.
Grown on cell culture (some require animals).
Techniques from molecular biology and immunology.
Proper safety precautions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How are viruses transmitted?

A

Through air, direct contact (fomites - any surface where microbes can live), by animals, contaminated food or water, body fluids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why is the common cold easier to catch than the flu?

A

Large particles fall downwards - flu virus is enveloped and therefore bigger, than common cold which will travel far.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Skin transmission diseases include:

A 
Abrasion/injury: HSV1 and 2.
Eczema: Papillomavirus
Injection/blood: HIV, Hep BCDG
Animal bites: Rabies
Insect vectors: Yellow fever
28
Q

Mucous membrane transmission disease include:

A

Conjuctiva: fingers, instruments; HSV1 an adenovirus
Genitourinary tract: sexual activity; HIV, HSV2, Papillomavirus, Hep B.
Oral: kissing, herpes viruses.
Alimentary tract: faecal-oral, rotavirus, hepititis A, poliovirus.
Respiratory tract: Aesorols, influenza, rhinovirus, measles, mumps and chickenpox.

29
Q

Rotavirus damages..

A

villi, reduces surfaces area.

30
Q

Poliovirus damages..

A

cells of anterior horn of spinal cord may destroy some motor neuron function resulting in paralysis, loss of muscle tone and deformities.

31
Q

Herpes virus is latent which means?

A

Never goes away, can be asymptomatic but can reactivate.

32
Q

Cytomegalovirus is a..

A

congenital infection.

33
Q

Epstein-barr virus and Burkitt’s lymphoma can cause

A

cancer.

34
Q

HIV causes..

A

muscle wasting.

35
Q

Smallpox shows what signs

A

lots of spots that turn into blisters filled with fluid which turn into pus. These fall of leaving pitted scars. Now successfully eradicated.

36
Q

Examples of naked helical virus

A

tobacco mosaic virus, no human viruses.

37
Q

Examples of enveloped helical virus

A

measles, mumps and rabies.

38
Q

Examples of naked icosahedral virus

A

polio virus and papillomavirus.

39
Q

Examples of enveloped icosahedral

A

herpes virus.

40
Q

Mosaic tobacco virus experiments important because

A

discovery that viruses were small and could only be grown in other living cells.

41
Q

Walter Reed’s yellow fever experiment is important because

A

discovery that viruses can be transmitted by insects.

42
Q

What are the 8 herpes viruses?

A

HSV1, HSV2, CMV, VZV, EBV, HHV6, HHV7, HHV8.

43
Q

Facts about herpes viruses?

A

Very common, cause a variety of diseases, all establish latency.

44
Q

Who is most susceptible to HSV1 and what does it cause?

A

Coldsore virus.
Uncommon in babies up to 6-9 months due to maternal antibody.
Normally contracted between 9 months to 5 years or adolescence and early adulthood due to kissing.
Rare after 30 years.
Lower socioeconomic groups tend to have an earlier primary infection.

45
Q

Where do latent viruses live and how do they reactivate?

A

Lives in nerve cells, latent until ganglia triggered where it moves back up neurone to skin and forms blisters. Reactivation triggered by a variety of stimuli such as stress, infection, UV light and menstruation.

46
Q

Symptoms of HSV1

A

Symptomatic recurrence in 60% cases. Tingling, itching, eruption of blisters, crusting.

47
Q

How long does each infection of HSV1 last?

A

10 days.

48
Q

HSV1 complications

A

Can affect skin if sufferers have eczema. Can spread on immunocompromised patients. Can cause blindness if reaches eye.

49
Q

What does HSV2 cause

A

Genital herpes

50
Q

Primary infection of genital herpes may be severe - true or false

A

True

51
Q

Where can lesions of HSV2 spread?

A

Cervix in females and buttocks and thigh in males.

52
Q

What percentage of patients develop meningitis from HSV2?

A

25%

53
Q

How long do fever and pain associated with HSV2 last??

A

3 weeks

54
Q

HSV2 explain

A

Starts with small macules and papules in infected area, develops into diverse vesicles which develop into ulcers.

55
Q

Symptoms of HSV2

A

Differs between the sexes, for females - painful lesions on vulva and cervix. 10-15% may develop urinary retention syndrome. Up to 25% will develop aseptic meningitis. Males - Lesions occur on glans penis or penile shaft but can also occur on buttocks, thighs and perineum. In severe primary infection, sacral radiculomyelitis may occur leading to urinary retention and meningoencephalitis.

56
Q

Frequency and healing of HSV2

A

During recurrence new lesions appearing delays healing by up to 15 days.
Up to 8-9 recurrences a year for 1/3 patients but recurrence is milder than primary infection.
HSV1 causes 30% primary genital infection in developed countries and recurrence is less likely with this strain.
60-80% of patients recurrence is asymptomatic.

57
Q

Neonatal herpes incidence and mortality

A 
UK 1/60,000 deliveries
USA 1/2000-5000 deliveries
Skin/eye/mouth - low mortality
Neurological in CNS - 50% mortality or neurologically impaired
Disseminated - 80% mortality
58
Q

HSEncephalitis incidence and mortality

A

1/200,000 10^6

Untreated patients about 70%, only 2% of those who recover will return to normal neurological function.

59
Q

Symptoms of HSE

A

Flu like symptoms for 2 weeks preceding onset of neurological symptoms
Fever continues with neurological symptoms including altered consciousness that increases in severity and may result in coma and death.
Affects the temporal lobe - function and memory.

60
Q

Treatment for HSV

A

Acyclovir IV, tablet or cream
Prompt treatment needed for HSE
Also effective against VZV, less so against beta and gamma herpes infections (CMV, EBV)

Acyclovir molecules enter cell and converted to acyclovir monophosphate by the HSV enzyme thymidine kinase (TK). Enzymes in human cell add two more phosphates to eventually form the active drug acyclovir triphosphate which competes with 2-deoxyguanosine triphosphate (dGTP) as a substrate for viral DNA polymerase, as well as acting as a chain terminator. In actual infection the HSV releases its naked capsid that delivers DNA to the human nucleus, the active drug acyclovir triphosphate exerts its action on the viral DNA located in the nucleus.

61
Q

Varicella zoster virus causes what?

A

Primary: Chickenpox
Recurrent: Zoster/shingles

62
Q

How is chickenpox spread?

A

Direct contact or respiratory

63
Q

What is the incubation period for chickenpox?

A

10-21 days

64
Q

Symptoms of chicken pox

A

Fever, general malaise for 2- 4 days followed by a centripetal spread of vesicular rash, itchy, on skin and mucous membranes. Vesicles appear in crops for 2-4 days, 100-300 lesions.

65
Q

Complications of chickenpox

A

Usually uncomplicated but can cause complications if immuncompromised such as pneumonia, hepatitis, pancreatitis, encephalitis, secondary skin infections such as s.aureus.
If pregnant:
First 20 weeks: Congenital (fetal) varicella syndrome (limb hypoplasia, microcephaly, cataracts, growth retardation and skin scarring) - incidence 1% in first 12 weeks and 2% in weeks 13-20.
In 2nd and 3rd trimester - Herpes zoster in an otherwise healthy infant
A week before to a week after delivery - neonatal chickenpox - severe and even fatal disease in the neonate.

66
Q

Treatment for neonatal chickenpox

A

Zoster immune globulin given to neonate, possible aciclovir.

67
Q

Where is EBV latent?

A

B-Lymphocytes

Microbiology - RA (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions