Global health - Infectious disease/AIDS - history and progression

Question 1

Identify the current burden of infectious diseases and their disparities worldwide

Answer 1

Infectious diseases are the leading cause of death in sub-Saharan Africa

Question 2

List the six commonest infectious causes of world mortality and some of the causes underlying their high incidence

Answer 2

1. Lower respiratory infections- 3.9M
2. HIV/AIDS-2.8M
3. Diarrheal diseases -1.8M
4. Tuberculosis- 1.6M
5. Malaria- 1.2M
6. Measles-0.6M

Question 3

define incidence

Answer 3

Number of new cases of a disease within a specified time interval. No. of new cases in a population in a given time period / No. of disease-free persons at the beginning of that time period

Question 4

define prevalence

Answer 4

frequency of a disease in a population at a point in time (point prevalence). Prevalence is a proportion. It is the only measure of disease occurrence that can be obtained from cross sectional studies

Question 5

define mortality

Answer 5

Number of deaths attributed to a specific condition in a given time period. Scores are generally expressed as number of deaths per 1000 individuals per year

Question 6

difference between incidence and prevalence

Answer 6

incidence measures new cases while prevalence measures all, cases new and old. The prevalence is dependent upon the
number of new cases (incidence), and the time that they remain cases before they die or recover (duration of disease). Individuals only leave the “pool” of prevalent cases when they recover or die.

Question 7

define morbidity

Answer 7

The number of cases of ill health, complications side effects attributed to a particular condition over a paricular time period. state of being unhealthy or diseased

Question 8

What is the difference between Mortality and morbidity?

Answer 8

Morbidity refers an incidence of ill health in a population. Mortality refers to the incidence of death or the number of deaths in a population.

Question 9

what is a case

Answer 9

Person who has the disease, health disorder or suffers the event of interest

Question 10

List the drivers of an AIDS epidemic, success and challenges of the response

Answer 10

AIDS epidemic controlled by:
Broad access to Anti-Retroviral Therapy. Effective HIV prevention methods- Safer sex, safer injection practices, condom use and male circumcision. Decline in HIV prevalence in pregnant women. Interventions have only been able to drive HIV infection rates down to a certain level and in order to further reduce incidence, biomedical tools will be needed (an effective vaccine)

Question 11

what could incidence increase be because of

Answer 11

could be as a result of better diagnosis and better treatment –>  disease sufferers live for more prolonged period; mortality rates will drop.

Question 12

Understand the impact of prevalence incidence and how these data can be used to guide and monitor policy and interventions

Answer 12

HIV infection in the UK:
The numbers of new cases of HIV being diagnosed each year (incidence) is rising. The numbers of deaths from AIDS has declined, due to improved treatment (HAART). Therefore the duration of disease is increasing. The consequence is a steep increase in the prevalence of HIV (the number of people living with HIV).

Question 13

explain the relationship between prevalence and mortality

Answer 13

For diseases where treatment confers survival benefit (eg ART for people living with HIV) the mortality falls as people start ART. Hence these people survive and overall population level prevalence increases(fewer people dying an exiting the pool). For diseases that are rapidly fatal (e.g. Ebola) the mortality is rapid and high and so large number of cases but overall prevalence is low.

Question 14

HIV prevention

Answer 14

Safer sex
Safer injection practices
Condom use
Male circumcision

Question 15

what are the leading causes of death

Answer 15

heart disease, cerebro-vascular disease, respiratory Infections, HIV/AIDS and COPD