1. Epidemiology and Disease
Biotechnology I

2. Essential Question(s)
What is the role of epidemiologist?
When is a disease an epidemic, a pandemic?
How are infectious diseases transmitted?

3. Epidemiology
Definition- Field of science that studies the distribution and cause of diseases or conditions of a population
Science examines
Incidence and spread of the disease
Prevention and control of infectious and non-infectious disease
Take into consideration
Environment
Agent
Host

4. Epidemiologists Definition Job Description
Person trained to identify and prevent diseases in a given population
Job Description
Identify factors that cause disease or how that disease is transmitted
For infectious diseases- identify the pathogen
For non-infectious disease – identify environmental factors that may be responsible for its prevalence
Ways to prevent the spread of the disease

5. Epidemiologists Measure:
Incidence rate – total of new cases within a calendar year
Prevalence – number of people of infected any given time
Morbidity rate – Number of individuals in a population that are ill
Mortality rate – Number of individuals in a population that die of the disease

6. Disease Outbreak Classified as
Endemic- Particular to specific region; number of cases remains constant
Epidemic – increase in the number of cases in a given geographical area
Pandemic –Increase in number of cases in different parts of the world.

7. Pathogen Reservoirs Reservoirs of Pathogens
Transmission of infectious agents involves movement from a source to portal of entry
Source of infectious agent- reservoir
Non-living sources- soil and water
Ex. Tetanus
When spores of Clostridium tetani, widely distributed in soil, contaminate a wound
Considered a non-communicable disease
Cannot transmit from an infected to uninfected individual

8. Pathogen Reservoir Source of infectious agent- reservoir
Living sources
Animal reservoir
Involve microorganisms that can infect both humans and animals
Ex. H5N1 Bird Flu Virus- transfer when come in contact with sick or dead poultry
Ex. Ebola Virus – Fruit bat or monkey

9. Pathogen Reservoirs Living Sources
Human reservoirs- principle reservoir for microorganisms that cause disease
Act as a source of contagion for others
Considered a contagious disease or communicable disease
Moves easily from one individual to the next

10. Spread of Disease Modes of Transmission
Contact transmission- comes from either direct or indirect contact
Direct contact transmission occurs
Skin to skin contact
shaking of hands, kissing, sexual contact, contact with open wounds
Ex. Syphilis, herpes, staphylococcal infections
Droplet transmission- sneezing, coughing, or speaking in close contact with an infected individual
Ex. Pneumonia, influenza, whooping cough

11. Spread of Disease- Contact Transmission
Indirect contact transmission- spread through inanimate non-living object
Inanimate objects like -bedding, towels, clothing, dishes, eating utensils,
Ex. Common cold, hepatitis B infection

12. Spread of Disease Modes of Transmission
Vehicle Transmission- spread through
Air- airborne microorganisms – from other animals, plants, water, and soil
Common when Individuals crowded together indoors or climate controlled building-
Ex. Measles, chickenpox, tuberculosis
Water
Thrive in polluted water contaminated with fertilizer and sewage;
Ex. cholera
Food products
Improperly cooked or improperly refrigerated food or unsanitary conditions associated with food handling
Ex. Salmonellosis

13. Spread of Disease Modes of Transmission
Vector Transmission- transmission of an infectious agent by a living organism to humans
Transmit two ways
Mechanical vectors-passively transmit disease with their bodies
Ex. Housefly –commonly feed on fecal matter then fly and feed on human food transmitting pathogens along the way
Biological vectors – pathogen complete part of their life cycle within the vector
Ex. Mosquitoes and Malaria

14. Summary

15. Control of Communicable Diseases
Different ways to prevent the spread of disease
Quarantine and Isolation of individuals with disease
Separation of animals and humans that have been infected or exposed to a communicable disease from the general public

16. Control of Communicable Diseases
Immunization – use of vaccine to protect public from the spread of communicable disease
Vaccine is the injection of killed, inactivated or fully virulent organism to induce one’s immune system
Ex. Ebola vaccine –contains parts of virus

17. Control of Communicable Diseases
Removal of Pathogens from Food and Water
Proper sewage treatment and drinking water disinfection
Chlorination of municipal water
Food industry
Pasteurization of Milk
Proper heating of canned food products

18. Control of Communicable Diseases
Vector control
Identification of vector
Most notable vectors are
mosquitoes, lice, ticks and fleas
Disruption of vector’s habitat and breeding ground through pesticides and poisons

19. Answer the Following Questions:
Explain the difference between epidemic and pandemic.
What are the job responsibilities of an epidemiologist?
Explain the difference between morbidity and mortality rate.
How are pathogens that enter the body through the respiratory tract generally transmitted?
What is a vector? What are some common vectors of infectious disease?
How do we control the transmission of waterborne and foodborne pathogens?
What is a vaccine?