Flashcards in Global Patterns of disease I Deck (18):
What is epidemiology based on?
It is based on the ability to quantify occurrence of disease in populations
What is a 'case' in epidemiology?
Person with disease, health disorder or suffering from event of interest
What is prevalence?
Frequency of a disease in a population at a point in time. It is the number of cases in the population/ number of people in the population. It is used to measure the burden of disease in a population
What is incidence?
Quantification of the number of new cases of a disease within a specified time interval
What is the difference between prevalence and incidence ?
Incidence new cases whereas prevalence measures all cases
How is incidence estimated?
By defining the time period and the denominator- the total population at risk. And an accurate test is needed to define a true case
What is mortality?
Number of deaths from a disease. It is the deaths from disease in a given time period/ population at the start of the time period
What does it mean when mortality= incidence?
Epidemic is stable
Explain the relationship between prevalence and mortality
Define prevalence and mortality. For diseases where treatment confers survival benefit (e.g. ART for people living with HIV) the mortality falls as people start ART. Hence these people survive and overall population level prevalence increases.
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.
What is morbidity?
Morbidity is the state of being diseased/ unhealthy
What are mortality rates expressed as?
Number of deaths per 1000 individuals per year
What are the leading causes of death?
Heart diseases, cerebra-vascular disease, respiratory infections, HIV/AIDs, COPD. In 3rd world countries, 58% due to malnutrition or deficiencies
What are the leading causes of death due to infectious diseases
lower resp, HIV, diarrhoea disease, TB, malaria, measles. Infectious diseases are leading cause of death in sub-saharan Africa
What are age standardised death rates?
The age-standardized mortality rate is a weighted average of the age-specific mortality rates per 100,000 persons, where the weights are the proportions of persons in the corresponding age groups of the WHO standard population-Measuring how many people die each year. Numbers help authorities determine whether they're focusing on right public health actions to reduce numbers of preventable deaths and disease.
What is the basic reproductive number?
Average number of secondary cases from the emergence of a single primary case
What factors affect R0?
Duration of incubation period, peak infectiousness and how quickly infectiousness decreases
Case studies of recent epidemics
SAR 2003, West Nile Virus 1999, HIV 1 1982, Malaria, MERS, Ebola, Zika