Lecture 6 epidemiology Flashcards
Father of Epidemiology
John Snow, identified London Cholera outbreak
Miasma theory is?
Disease cause from bad air
Two types of epidemiology
- Descriptive
- analytic
Descriptive epidemiology is?
- Study the occurrence and distribution of disease
- Generate hypotheses about the determinants of disease by considering who, what, when and where
- Person, place, and time
- Reveals the extent of the public health problem being investigated
- Identifies the populations that are most at risk of acquiring the disease
Analytic epidemiology is?
- Investigate a hypothesis about the cause of a disease
* Answer why and how
Epidemiology means…
Studies a population and overviews health-related issues
Core Epidemiologic Functions
- Public health surveillance
- Field investigation
- Analytic studies
- Evaluation of public health services
- Policy development
What is listeriosis?
Infection caused by Listeria monocytogens, foodborne. Can live o refrigerated food but can be killed by cooking. Outbreak in colorado- caused by cantaloupes (3rd deadliest outbreak).
What defines an outbreak
occurs when the observed number of cases or amount of disease is greater then expected at a particular time and place
What is incidence?
is the number of new cases of disease that develop in the population in a given time
What is prevalence?
is the number of existing cases of disease in the population in a given time
How are cases identified?
- Routine surveillance (main way)
- Report by physicians, clinical laboratories, public health laboratories
- Consumer complaints
What is a case definition?
• A set of standard criteria for deciding whether a person has a particular disease or health-related condition
What are some epidemiological molecular methods?
• PFGE
• MLVA
• Sequencing
- Gene
- Whole genomeWhat is pulse field gel electrophoresis (PFGE)?
• Used to generate a DNA fingerprint for a bacterial isolate
What is MLVA (Multiple locus variable-number tandem repeat analysis)?
- Uses PCR and gel electrophoresis to analyze polymorphisms in tandemly repeated DNA sequences
- Often used in conjunction with PFGE
What is Pulse NET?
- Outbreak detection system
* National surveillance network of CDC, state and local health laboratories
What is an epi curve?
• Shows the number of illness over time – can use date of symptom onset or lab-confirmed diagnosis
How can pathogens of food born illnesses be spread?
- Contaminated food or water
- Direct contact with an ill person
- Indirect contact with an infected animal
What modes of transmission are considered when looking for a source?
- Specific pathogen causing illness
- Person – age
- Place – where ill cases reside
- Time – incubation period of the pathogen, seasonality
What are two ways to test hypotheses?
- Analytic epidemiology
* Laboratory testing of suspect foods
What are some commonly used analytic studies?
- Case control
- Cohort study
What are some control measures if a source is identified?
- Recalls
- Disinfect food facilities
- Temporary closures
- Notify consumers
- Discard suspect food items
- Provide information on correct methods to prepare food
- Notification may particularly target high risk individuals
- In this outbreak, elderly and pregnant women at highest risk
Types of epidemiology
- Communicable or vaccine preventable disease epidemiologist at local, state or national level
- Pharmaceutical
- Molecular
- Veterinary
- Infection Control/Hospital
- Applied
- Others
