Epidemiology Fundamentals Quiz

Introduction to Health Protection and Epidemiology

• This presentation covers health protection and epidemiology.
• The presenter, Roberto Vivancos, is a Consultant Epidemiologist and Professor in Public Health at the UK Health Security Agency/Warwick Medical School.
• The objectives are to understand health protection and epidemiology, communicable diseases and their control, and key epidemiological concepts.

Communicable Diseases

• Communicable diseases are transmissible, either directly or indirectly.
• They are infectious diseases.

Importance of Communicable Diseases

• Globally, communicable diseases contribute significantly to ill health.
• Globally, mortality and morbidity related to communicable diseases has decreased.
• International health regulations exist in 196 countries.
• Despite progress, high-impact epidemics (e.g., influenza, SARS, Ebola, Zika, and now Covid-19) continue.
• The control of previously common diseases allows new ones to emerge.

Timeline of Emerging Infections

• A timeline presentation shows emerging infectious diseases since 1998.
• The timeline visually displays the emergence of a variety of infectious agents and diseases.

Socio-economic Disparities and Infectious Diseases

• Developed and developing countries are affected differently by the burden of communicable diseases.
• Differences in socio-economic conditions exist between continents, countries, and within countries.
• More socioeconomically deprived groups face higher morbidity and mortality, driven by underlying co-morbidities like hypertension, obesity, and diabetes, and by poor living conditions and employment.
• COVID-19 has drawn attention to these disparities.

Disease Burden and GDP Per Capita (2017)

• A chart displays disease burden due to communicable diseases against GDP per capita.
• The chart provides insights into the relationship between economic development and the burden of communicable diseases.

Public Health Domains

• The presentation outlines three domains of public health.
• These are health improvement, health protection, and health and social care quality.
• The presenter will illustrate who performs the roles related to each domain and the duties associated with these roles

What is Health Protection?

• Health Protection is a core area of public health work.
• The focus is on protecting individuals, groups, and populations through expert advice and collaboration.
• This involves preventing and mitigating the impact of infectious, environmental, chemical, and radiological threats.

What is Epidemiology?

• Epidemiology studies the distribution and determinants of health-related states among defined populations.
• It involves applying these studies to control health problems.

Field Epidemiology

• Field epidemiology involves investigations in response to urgent public health problems.
• Its primary goal is to implement interventions quickly to lessen or prevent illness or death.

Epidemiology in Public Health Practice

• Epidemiology in public health practice involves identifying the agent, host, and environmental factors affecting health.
• It involves determining the relative importance of causes of illness in various segments of the population.
• Epidemiology also includes evaluating the effectiveness of programs and services to improve population health.

Process Model

• The presentation includes a flow-chart model of the epidemiological process. It details the steps required to solve health problems including data collection, assessment, hypothesis testing and intervention.

Purpose of Epidemiology in Public Health

• One of the purposes of epidemiology is not to provide treatment for patients in clinical settings. All other options are part of the purpose of epidemiology.

Delivery- Global Context

• Global initiatives in public health involve leadership, norms and standards, evidence-based policy, capacity building in technical support, monitoring health, research, and advocacy

Delivery- Epidemiology in Different Settings

• The delivery of epidemiology work takes place in several different settings (various countries or organizations)

The Epidemiological Triad

• The epidemiological triad illustrates the relationship between agent, host and environment.
• It suggests a fire analogy where air is the environment; fuel is the host, and heat (infectious agent) is the cause

Infectious Agents

• Infectious agents' key characteristics include infectivity, pathogenicity, virulence, disease, and incubation period.

Reservoir of Infectious Diseases

• Common reservoirs of infectious diseases include humans, animals, soil and water

Host Factors

• Host factors include behaviors like sexual practices and hygiene, along with susceptibility and response based on age, gender, ethnicity, genetics, nutrition and health.

Host Prevention & Control

• Strategies to prevent and control are related to health education, reducing exposure/risk behaviours, personal protective equipment, handwashing, immunisation treatment, contact screening, isolating those with illness, and prophylaxis.

Environmental Factors

• Environmental factors for disease transmission include water supply, sanitation, overcrowding, climate, airflow, humidity and temperature, and availability of health services

Mode of Transmission

• Direct transmission can occur through touch, droplets, or contact.
• Indirect transmission may involve vehicles (food, water) , vectors (animals) or airborne particles

Innate Defenses against Pathogens

• Innate defenses protect the body from pathogens via tears, saliva , skin, respiratory tract, mucus, and stomach acid amongst other mechanisms

Epidemiology Key Terms I

• An outbreak is an increase in disease or behaviour above expected levels in a defined location and time.
• A cluster is an unusual grouping of cases in a specified location and timeframe.

Epidemiology Key Terms II

• An endemic is a consistent presence of a disease in a population.
• A pandemic is a widespread disease occurrence across regions.
• R₀ (basic reproduction number) is a calculation of how easily a disease spreads.
• R_e (effective reproduction rate) is how easily a disease spreads considering existing immunity/vaccination rate.

Over to You...

• Examples of endemic and pandemic diseases are provided: Malaria (endemic) and Ebola and HIV/AIDS (pandemic).

Comparing Population Characteristics

• Using rates helps compare health problems in different populations.
• This considers variations in health between different groups (e.g., by sex or age).

Rate Calculation

• To calculate a rate, the number of cases, the population at risk, and the time period must be considered.

Scenario: Unexplained Pneumonia

• A case study of unexplained pneumonia at a veterans’ convention is presented.
• Key data (deaths and additional cases) are listed by date

Legionnaires' Disease

• Data relating to legionnaires' disease, by age group, is provided, including frequency, total size and percentage.

Prevalence

• Prevalence is the measure of how common a disease is, including new and old cases.
• Prevalence can be expressed both as a percentage, or the number of cases per n individual

Types of Prevalence

• Point prevalence measures the proportion of individuals with a condition at a specific time.
• Period prevalence considers the proportion of individuals with a condition during a time interval.
• Lifetime prevalence refers to the proportion of individuals who experience the condition at least once during their lives.

Incidence

• Incidence is the rate of new disease events over a specific time period.
• Incidence can be expressed per n individuals, or per n 'person-years'.

Person-Years

• Person-Years is a measure that combines the number of individuals observed and the duration of observation for each individual.

Calculating Incidence

• Calculating incidence requires identifying new cases, the number of people observed, and the observation period..

Relating Incidence and Prevalence

• A table connects high and low incidence levels with high and low prevalence for disease conditions

Factors Affecting Prevalence

• Factors influencing prevalence include incidence, recovery rates, mortality, and population transfer rates.

Summary

• This is a summary slide for the course content. The slides cover health protection and epidemiology aspects of communicable diseases
• Key terms and epidemiological concepts are covered.