Epidemiology I - AN SC 100 PDF

INTRODUCTION TO EPIDEMIOLOGY October 28, 2024 Today’s objectives Understand what epidemiology is and what it is used for Apply the basic concept of epidemiology to an example 2 3 Epidemiology allows us to study: -frequency of a disease/condition...

INTRODUCTION TO EPIDEMIOLOGY October 28, 2024 Today’s objectives Understand what epidemiology is and what it is used for Apply the basic concept of epidemiology to an example 2 3 Epidemiology allows us to study: -frequency of a disease/condition -how often it occurs -distribution -what populations/individuals are affected -causal factors -what causes a disease/condition? 4 The history of epidemiology 6 7 9 10 11 12 13 14 Epidemiology looks at…. How What When Who Where 15 Epidemiology looks at…. How individuals/populations are affected → clinical signs What causes →pathogen, causal factors, etc When they are affected → time or life stage Who is affected → characteristic of those affected such as age, sex, etc Where they are affected → location 16 17 Factors associated with disease risk Host factors: age, sex, “use”, genetics, immunity, etc Agent: biologic, chemical, mechanical, nutritional, etc Environment: geographic location, climate, water supply, pollution, etc 18 Example: Overo lethal white syndrome A genetic disorder in horses: two base pair mutation (p.Ile118Lys) in the gene endothelin B receptor gene (EDNRB). EDNRB is responsible for the proper development of both pigment cells and nerve cells during embryogenesis. Homozygous inheritance ie; 2 copies of the gene produces a pure white foal with undeveloped intestines A horse could be normal but carry the gene mutation (10.7% in American Paints and up to 94% in some overo lines 20 Example: Overo lethal white syndrome Clinical signs: inability to defecate within 12 hours of birth leading to severe colic signs Not feasible for foal to survive Genetic testing and careful breeding practices required 21 Example: Overo lethal white syndrome Clinical signs: inability to defecate within 12 hours of birth leading to severe colic signs Not feasible for foal to survive Genetic testing and careful breeding practices required 22 Example: Overo lethal white syndrome How individuals/populations are affected → failure to defecate 12hr after birth, severe colic, death What causes it →genetic When they are affected → in development and at birth Who is affected → horses with the overo coat colour (more specifically those with the homozygous gene for overo) Where they are affected → everywhere 23 Epidemiology can help to define and “solve” a health problem  Announcements Interactive lab this week based on Oct 25th material! Quiz 6 closes 10am on Wednesday Quiz 7 will take place in labs Friday Nov 1st Midterm 2 (see eclass for more details about content)