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Flashcards in Prions and retroviruses Deck (50)
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1
Q

Proteinaceous infectious agents

A

prions

2
Q

Prions induce a conformational alteration of a normal ____ protein from what to what?

A

CNS protein

from alpha helix to beta pleated sheets

3
Q

Prions are _________ protein aggregates that cause extensive _________ of neurons and produce fatal degenerative CNS diseases called what?

A

insoluble
vacuolation
transmissible spongiform encephalophaties

4
Q

What does spongiform refer to?

A

Presence of multiple vacuoles that make the tissue look like a sponge

5
Q

What is the normal prion protein called? What is the infectious form called?

A

PrPc

PrPsc

6
Q

What are normal prion proteins?

A

Surface components of neurons and glial cells

7
Q

What makes prions so hard to eradicate?

A

Very resistant to inactivation

8
Q

Where was Kuru endemic to?
How did people get it?
How did it stop?

A

Papa New Guinea
Engaged in ritual cannibalism - ate the liver and brain of esteemed person
stopped when they stopped eating people

9
Q

Which is the rapid variant of TSE?

A

CJD

10
Q

What is the sheep TSE called? Why is it aptly named?

A

Scrapie

Infected sheep scrape along fences and walls

11
Q

What symptoms does kuru produce? How is it transmitted?

A

spasticity and ataxia - infectious

Extinct

12
Q

What symptoms does CJD produce? how is it transmitted/acquired?

A

dementia, spasticity, seizures

infectious or inherited

13
Q

What does most forms of human TSEs have in common in terms of symptomology?

A

Most have ataxia as a feature

14
Q

What is the enzyme that retroviruses must carry with them?

A

RNA dependent DNA polymerase or reverse transcriptase

15
Q

What is the central dogma of molecular biology?

A

DNA –> RNA –> protein

16
Q

How do retroviruses integrate their genome if they have RNA?

A

RNA –> reverse transcriptase –> dsDNA –> integrate into host genome

17
Q

When the DNA is integrated into the host genome, what is the retrovirus now called?

A

a provirus

18
Q

When the provirus chooses to replicate, how does it accomplish this?

A

Uses host RNA polymerase to synthesize mRNA to manufacture viral protein, synthesize reverse transcriptase and makes its genome (ssRNA)

19
Q

What are the two big families of retroviruses?

A

Oncoviruses

Lentiviruses

20
Q

HIV-like viruses infect many animals without causing disease - e.g. monkeys. In what animals does it cause disease?

A

Equines and house cats (and humans)

21
Q

From what was SIV first isolated?

A

Japanese macaques

22
Q

What are the three different SIV variants?

A

SIVgm - green monkeys
SIVcpz - chimpanzee
SIVsm - sooty mangabey

23
Q

Why do we believe that HIV came from chimps?

A

SIVcpz found in Gabon serologically reacts with HIV-1

24
Q

How do we believe that HIV entered the human population?

A

Entered human population through bush meat trade in Africa, then sexual transmission

25
Q

What did SIVcpz probably evolve into to infect humans?

A

HIV-1 and HIV-0

26
Q

Which SIV serotype has 80-90% homology with HIV-2?

A

SIVsm

27
Q

What is the approximate period of incubation of HIV?

A

10 years

28
Q

How is HIV-2 different from HIV-1?

A

Low lethality, mainly in West Africa and incubation period closer to 20 years

29
Q

How did HIV go from Africa to Europe?

A

Cameroon was originally a german colony. After WW2, this colony was forced to leave and go back to Germany (then Danzig - now Poland), brought HIV with them

30
Q

P. ________ is characteristic of AIDS.

A

P. jiroveci (used to be called P. carinii)

P = pneumocystic

31
Q

What ultimately led to the discovery of HIV?

A

Found a high order of pentamidine to treat PCP (P. cariini pneumonia) in young, gay males - also high rates of Karposi Sarcoma at the time - noticed they were immunosuppressed and termed cause as GRID (now HIV)

32
Q

What does GRID stand for?

A

Gay-related immune deficiency

33
Q

Where is HIV huge? What is it considered in terms of public health?
What is a major issue for treatment?

A

West, east and south Africa
Pandemic
Affordability

34
Q

Soon after infection with HIV, what symptoms manifest? What is it associated with?

A

Flu-like illness which is associated with seroconversion

35
Q

What is seroconversion?

A

Period in which HIV antibodies are produced

36
Q

How many years does it take for immunosuppresion to develop?

A

years to decades

37
Q

What does HIV cause after a period of years?

A

CD4 cell depletion resulting in opportunistic infections and also dementia secondary to direct infection of CNS

38
Q

AIDS is reserved for who?

A

those with a CD4 count lower than 200 cells

39
Q

What is the normal range for CD4 cells?

A

1500-500

40
Q

Role of cofactors in accelerating the development of AIDS is controversial, but certain __________ appear to have roles.

A

mycoplasmas

41
Q

What are the different types of people infected with HIV?

A

non-progressers - infected with HIV but remain perfectly healthy
rapid progressors - CD4 count depletion within shorter time frame (~3 years)
HIV resistant - despite repeated exposure, no seroconversion

42
Q

Is it possible to completely eliminate HIV?

A

yes, with 50+ years of HAART

43
Q

What is the staple treatment for keeping HIV in check?

A

HAART - highly active anti-retroviral therapy

44
Q

What is an issue with HAART?

A

very expensive

45
Q

At what CD4 count does a person basically have normal immunity?
What is an HIV CD4 count where opportunistic infections may become a problem?

A

500+
499-200
(although not definite numbers, some people can be better with less, some worse with more)

46
Q

What is the Kaposi sarcoma AIDS defining agent?

A

Human herpes virus 8

47
Q

How is HIV transmitted?

A

heterosexual sex, needle sharing for IV drugs, hemophelia treatment, blood transfusion, homosexual sex as well

48
Q

What is the risk to caregivers after a needle prick?

A

1/300

49
Q

How acn the seroconversion rate of accidental healthcare exposure be decreased?

A

with PEP - post-exposure prophylaxis (combivir + Kaletra)

50
Q

What may ultimately be one answer to the HIV pandemic?

A

HIV vaccines