HIV- epidemiology and transmission Flashcards Preview

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Flashcards in HIV- epidemiology and transmission Deck (18):
1

Is it an RNA or DNA virus? It is single stranded or double stranded? What size is its genome?

ssRNA lentivirus (slow/long-term infection)
10 kb length

2

What are the two distinct viruses in HIV? What cells does HIV infect?

HIV 1 (mostly what we're studying) and HIV 2
Infects CD4 positive cells (T-lymphocytes, monocyte/macrophages, dendritic cells)

3

What are some of the aims by 2020 of the UNAIDS strategy?

90% knowledge of HIV status
90% treatment coverage

4

In who were cases of pneumonia and Kaposi's sarcoma seen in 1980?

In 1983, there was a link of contaminated blood with lots of death cases. What happened later in that same year?

In 1984, what were they able to do with HIV in labs?

In 1985, FDA approved HIV antibody test. What did this help with?

In 1987, the first anti-HIV drug was approved but what happened in 1989?

Gay men

Retrovirus isolated from T-cells

Able to culture, clone and molecularly characterise it

Antibody test helps identify HIV positive people due to their response

FDA approved a sensitive HIV antigen test which was much more sensitive than previous tests

5

Who was Montagnier and Barre-Sinoussi?

Who was Robert Gallo?

Montagnier and Barre-Sinoussi published their research describing the HIV virus but couldn't identify it as the cause of AIDS

Gallo then used the same sample and linked HIV to being the cause of AIDS

6

Is HIV closely related to HTLV- I (leukemia)? How was this discovered?

No, it was previously thought to be but after complete genomic sequences were published in 1985, it was renamed the human immunodeficiency virus instead

7

What are the 4 distinct types of HIV-1? Where are they found?

Group M (main) found worldwide
Group O (outlier) confined to Cameroon/ Gabon
Group N found only in 6 people in Cameroon
Group P found only in 2 people in Cameroon

8

What is the cross species transmission of SIVcpzPtt in chimps to group M and N HIV1 in humans due to?

Bush meat trade- not sexual!

9

SIVcpzPtt was found to be the virus in chimps that HIV 1 evolved from. SIVcpz is a combination of which two viruses? How did this virus arise?

SIVcpz is a combination of SIVrcm (Red capped mangabey) and SIVgsn (Greater spot-nosed monkey)

Probably through predation

10

So groups M and N of HIV 1 came from SIVcpz but where did groups O and P come from?

SIVgor is thought to have caused Group P and O

11

Humans have been exposed to SIV in monkeys for centuries so what are the theories of why HIV has only recently emerged?

Deforestation, urbanisation, travel and unsterilised needles may cause this

12

The M group ancestor is estimated to have been around 1931 (+/- 20 years). What are the three causes of such a rapid spread thought to be?

International travel
Blood transfusions
Intravenous drug use

13

What relationship is there between cost of disposable needles and the transmission of HIV?

Negative correlation- as needle costs get lower, HIV transmission increased

14

The transmission of HIV depends on contact with blood or mucous membranes. What major route are there for transmission of HIV in humans?

Sexual contact

15

Why is transmission of HIV actually very inefficient?

Protective layer of mucosal layer
Limited target cell availability

16

What is meant by a 'founder virus'?

Only one virus is needed to establish the infection

17

Mothers can transmit HIV to their children. These account for 90% of infant infections and there is a 50/50 chance of passing it on as a mother. When are the highest risks for this transmission? What is currently done to reduce the rates of mother to child transmission?

During delivery (blood contact) and breast-feeding

Application of antiretroviral therapy and avoidance of breast-feeding reduces rate of transmission to 2% (however some antiretrovirals are toxic during pregnancy)

18

What are the current HIV diagnosis tests? What are the pros and cons?

Based on detecting antibodies to HIV
Can be used outside a lab
Instant results
99% accurate

However need to be followed up by confirmatory tests such as ELISA, Western blotting etc.