Transcript Epidemiology and Disease

Epidemiology and
Disease
Biotechnology I
Essential Question(s)
What is the role of epidemiologist?
When is a disease an epidemic, a
pandemic?
How are infectious diseases transmitted?
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
Epidemiologists
Definition
 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 diseasesidentify the pathogen
 For non-infectious disease –
identify environmental factors
that may be responsible for its
prevalence
 Ways to prevent the spread
of the disease
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
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.
Pathogen Reservoirs
 Reservoirs of Pathogens
 Transmission of infectious agents
involves movement from a source
to portal of entry
 Source of infectious agentreservoir
 Non-living sources- soil and water
 Ex. Tetanus
 When spores of Clostridium
tetani, widely distributed in soil,
contaminate a wound
 Considered a noncommunicable disease
 Cannot transmit from an
infected to uninfected
individual
Pathogen Reservoir
 Source of infectious agentreservoir
 Living sources
 Animal reservoir
 Involve microorganisms
that can infect both
humans and animals
 Ex. H5N1 Bird Flu Virustransfer when come in
contact with sick or
dead poultry
 Ex. Ebola Virus – Fruit
bat or monkey
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
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
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
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
Spread of Disease
 Modes of Transmission
 Vector Transmissiontransmission 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
Summary
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
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
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
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
Answer the Following Questions:
1. Explain the difference between epidemic and
pandemic.
2. What are the job responsibilities of an
epidemiologist?
3. Explain the difference between morbidity and
mortality rate.
4. How are pathogens that enter the body through
the respiratory tract generally transmitted?
5. What is a vector? What are some common
vectors of infectious disease?
6. How do we control the transmission of
waterborne and foodborne pathogens?
7. What is a vaccine?