Chapter 3 HIV Transmission

Question 1

How is HIV infection transmitted

Answer 1

Sexual intercourse
HIV infected blood that passes directly from an infected person to the body of another person.
From mother to baby during pregnancy, child birth or breastfeeding.

Question 2

What is needed for a person to become infected with HIV

Answer 2

Virus must find way into person blood stream and must be able to embed itself.

Likely to occur is there are sufficient quantities of virus in the person in semen vaginal fluid etc.

Virus able to enter bloodstream

Virus is in bloodstream long enough to take hold.

Question 3

What are the contributing factors influencing spread of HIV

Answer 3

Gender: more likely that women will be infected than men. Fact that semen stays in woman’s body for a period of time. Vagina has a large surface area of mucosa exposed to secretion during sex.

Age: younger people like those in their reproductive years are most vulnerable. These ones may engage in sex early due to low self esteem, pessimism peer pressure,sexual coercion and money.

Question 4

What factors make woman vulnerable

Answer 4

Genital tract aren’t fully mature
They don’t have copious vaginal secretion
Vaginal mucosa lacerates easily.

After menopause the thinning and increasing dryness of the mucosal walls.
Tearing or bleeding of genital anal area.

Question 5

List some other STIs

Answer 5

Genital ulcers are particularly vulnerable to HIV.
Sypilis
Chancroid
Herpes

Discharge
Gonorrhoea
Chlamydia
Trichomoniasis

Question 6

What role does socioeconomic and cultural conditions play in the transmission of HIV

Answer 6

#High unemployment levels force people to move and leave families causing new sexual networks 
# tradition sometimes denies woman authority over their bodies 
#extreme poverty forces women to sell sexual services. 
#those in poor communities don't have access to health care. 
#lack of information and support services.
#alcohol abuse.
#

Question 7

What factors play in the acquisition of HIV

Answer 7

Frequency of sex
Multiple sex partners 
Condom use
Immunological status
Presence of other STIs
Trauma during sex like bleeding

Question 8

Define viral load

Answer 8

The amount of viral RNA detectable in the blood of an infected person. The quantitative PCR technique is used to count the HI virus particles or viral load in blood of HIV+ person.

Question 9

When is an HIV+ person most infectious

Answer 9

HIV+ people are considered most infectious soon after becoming infected with virus during seroconversion and during final phase of aids when severe symptoms appear.

Question 10

When is the greatest risk of HIV infections from blood transfusion

Answer 10

Occurs in the infectivity window period which is the period between a person being infected with HIV and a lab test detecting and confirming presence of antibodies or virus particles.

Question 11

Give examples of HIV antibody test

Answer 11

First gen tests
Enzyme immune assays with 45 day window period.

PCR procedure
Nucleic acid testing with window period of 12days

Question 12

How is HIV transmitted through needle sharing

Answer 12

When needles are shared drug users usually inject directly into their blood stream and draws up blood which remains the syringe and next user will then inject that blood into their body.

Question 13

What quantity of infected blood need to be present for HIV transmission

Answer 13

The risk of HIV infection is directly proportional to the concentration of HIV in the blood.

The higher the concentration of HIV in blood the lower the quantity required to transmit the virus.

Question 14

How long can HIV survive outside the body

Answer 14

As soon as HIV is no longer inside body fluid or when exposed to oxygen heat and dryness in atmosphere it dies. It can survive outside body for many hours if it remains in some or other body fluid.

HIV can survive and remain infectious up to 24hours in body fluid outside of body.

Question 15

How does a mother infect her baby

Answer 15

Via the placenta during pregnancy

Through blood contamination during labour or

breastfeeding

Question 16

How does breast feeding affect a baby with HIV+mother

Answer 16

It affects baby’s risk for HIV infection. Best time span to breastfeed is 6 months.
Best that mother’s on ARVs breastfeed until 6mnths mother should then continue with breastfeeding for another 6 months with complimentary foods. When baby 12 months old breastfeeding can be stopped.

Question 17

What are the 3 main categories of HIV prevention

Answer 17

Behavioural interventions include efforts to change people’s behaviour to make sexual and drug using behaviour safer.
Condom use
One partner
Abstaince

Biomedical interventions involve development and use of biological or medical tools to prevent HIV infections
HIV testing
Circumcision
ART
PMTCT
Microbicide
Vaccine

Structural interventions focus on social political economic and physical environment of individual that can impact vulnerability to HIV.
Physical environment
Social political and economic structure

Question 18

What is PEP and nPEP

Answer 18

PEP= post exposure prophylaxis is short term antiretroviral treatment taken after exposure to HIV

nPEP= non occupational post exposure where uninfected person receives ART after sex with HIV infected person.

Question 19

What is a vaccine

Answer 19

Is a harmless substance that creates an immune response similar to infection which is used to build immunity or resistance to a later real infection.

In other words it teaches body to recognise and defend against future infection by bacteria and viruses that cause disease.

Question 20

Which 2 processes does vaccines aim to copy

Answer 20

Humoral response

Is response where immune system produces antibodies that recognise specific pathogen in blood and neutralise it’s activity before it can infect body cells

Cellular response

Is response where white blood cells like CD4 T cells CD8 T cells are formed after pathogens have infected some body cells.