Download Measles and Small Pox

CH. 10 PART 1
Introduction to Infectious Disease
CH. 9 REVIEW (NON-INFECTIOUS
DISEASES OF RESPIRATORY AND
CARDIOVASCULAR SYSTEMS)
Experimental vs. Epidemiological
Evidence
Experimental
Epidemiological
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Direct causative link between an action (ie
smoking) and a disease (ie lung cancer)
Two types of experimental evidence linking
smoking and lung cancer:
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Tumor development in humans similar to
tumor development in animals exposed to
cigarette smoke
Carcinogens identified in tar
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Other examples
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Dogs exposed to filter-tipped cigarettes= no
cancer (but still showed pre-cancerous
changes)
Dogs exposed to non-filtered cigarette smoke
developed cancer
Smoking machines (simulate inhalation
patterns) collect oily, black build up from
cigarette smoke and analysis of this tar show
carcinogens
Carcinogens of tar painted on the skin of mice
lead to cancerous growths on the mice
Experiments on cells grown in cultures and
exposing cells to carcinogens and analyzing
behavior and changes
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Epidemiology is the study of diseases in
populations of humans or other animals,
specifically how, when and where they occur
can never prove causation
cannot prove that a specific risk factor
actually causes the disease being studied
Can only show that this risk factor is
associated (correlated) with a higher
incidence of disease in the population
exposed to that risk factor
Higher the correlation = the more certain the
association (but it cannot prove the
causation)
Data collected about people’s habits (ie
smoking) and their health
Large groups of people used
Researchers look for correlations between
smoking and particular disease (such as
coronary heart disease)
Coronary Heart Disease (CHD)
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Disease of coronary arteries that supply the heart with
oxygenated blood…leads to malfunctioning heart
Long term degenerative disease
Three forms:
– Angina pectoris shortage of oxygenated blood to the heart but
NO death of heart tissue; main symptom is sever chest pain
during exertion
– Heart attack (myocardial infraction) blood clot in moderately
large portion of coronary artery; heart muscle dies b/c of no
oxygen
– Heart Failure blockage of main coronary artery; heart weakens
and cannot pump efficiently
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Leading cause of long-term illness and death in US and EU
Affects affluent countries
Governments have taken steps to reduce these statistics
– Lifestyle changes (exercise, low-animal fat healthy diets, no
smoking
– Death rates have dropped in last 25 years (reasons unknown)
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Finland, US, Australia
1st set of Treatments for CHD
• Drugs to lower BP
• Drugs to decrease risk of blood
clotting
• Drugs to prevent abnormal heart
rhythms
• Drugs to reduce retention of fluids
• Drugs to reduce cholesterol
concentration in blood
2nd treatment of CHD
• Coronary artery by-pass
operation
• Use blood vessel from chest, arm,
or leg to replace diseased vessel
• New vessel carries blood from the
aorta to another part of the
heart(past the blockage)
• Multiple by-passes may be
necessary
• By-pass surgeries increased
drastically (3x) in UK in 1980s
3rd treatment of CHD
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Complete heart transplant
Last resort
Difficulty finding donors
Must have matching tissues (genetic markers) so
immune system of recipient doesn’t attack heart
Heart-lung transplants more effective than heart
only transplants
Drugs are taken to suppress immune system
(unpleasant side effects)
Expensive
Decision of who receives hearts (should the person
who has continued smoking receive a heart over
someone who has listened to their doctor and
started living a healthy life style)
Primary health care can be used to reduce this
expensive cost
1st CHD Prevention: Screening for CHD
• Screen population for individuals at risk
of developing CHD
– High blood pressure
– High cholesterol concentration in blood
– Heart rhythm during exercise
• Doctors can screen on a regular basis
– Regular monitoring of blood pressure
• Advice given to those at risk to stop
smoking, eat healthier, and exercise
Prevent CHD by Lowering High BP
• Medications
– Stanins- drug that lowers blood cholesterol
• Reduce salt intake
• Diet changes not always successful
2nd Way to Prevent CHD: Healthy
Lifestyle
• Advertising & Public health
education to:
– Healthy lifestyle at an early age
– Encourage aerobic exercise
• Involves changing diet, reducing
alcohol intake, and stop smoking
• Exercising reduces blood pressure
Mortality Rate of CHD and Stroke
• Began to decrease in 1970’s
• Why?
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Decrease in saturated fat and smoking within the population
Better emergency rooms in hospitals
Improvements in treatments of heart attack patients
Maternal nutrition (epidemiological evidence)
• Higher birth weight associated with lower blood pressure in middle
age people
• High weight at age 1 is associated with lower risk of diabetes AND
low levels of LDL cholesterol in blood
• THEREFORE:
– Better maternal nutrition in the early and middle 20th century = better
protected later generations
– CHD is more common among the low socioeconomic populations that the
affluent populations
» Think about locations of fast food restaurants in inner cities vs.
suburban neighborhoods
Disease
• Illness or disorder of the body or
mind that leads to poor health
• Associated with a set of
symptoms
• Infectious vs. non-infectious
• Pathogens
– Cause infectious
disease/Communicable diseases
– Usually microorganisms
– Viruses, bacteria, fungi, protists
Infectious disease
• Caused by pathogens
• Short vs. long lived
• Spread various ways
– Direct contact (pathogen only survives inside human)
– Indirect contact (food, water, feces, animals and
insects)
• Carriers
– People that can spread the pathogen while they do
not have the disease themselves (or show symptoms
of the disease)
– Difficult to trace as the source of infection
Transmission Cycle
• Way the pathogen passes from one host
to another
• Control methods
– Attempts to break transmission cycle by
removing conditions that favor the
spread of the pathogen
– Can only be used when the cause of
disease and method of transmission are
known and understood
• Causative agents
– Agents that cause disease
– Example of control method: Vaccination
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Makes us immune
Pathogens cannot live in us
Pathogens cannot reproduce
Pathogens cannot spread to others
Terms to Know
• Incidence
– Number of people who are
diagnosed with a specific
disease over a certain period
of time (usually a week,
month, or year)
• Prevalence
– The number of people who
have the disease at any one
time
• Mortality
– Death rate from a specific
disease
• Vector
– An organism which carries a
disease from one person to
another or from an animal
to a human
• Endemic
– Diseases that are always
in populations
– Ex. Tuberculosis (entire
human population)
– Ex. Malaria (tropical
regions)
• Epidemic
– When there is a sudden
increase in the number
of people with the
disease in a region
• Pandemic
– When there is a sudden
increase in the number
of cases of a specific
disease throughout a
continent or the world
Infectious Disease Group Activity
Period 1
• Teams of 5 (assigned by
teacher)
– 4 teams total
• Team needs to select a
team leader
• Each person on your team
needs to pick a number 1-5
• Follow Guidelines for Team
Session 1
Period 5
• Teams of 5 (assigned by
teacher)
– 3 teams total
– One team will have six people
• Team needs to select a
team leader
• Each person on your team
needs to pick a number 1-5
• Follow Guidelines for Team
Session 1
Disease JigSaw
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6.
Cholera
Malaria
HIV/AIDS
Tuberculosis
Measles
Small pox
Information to Discuss and Collect
About Each Disease
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Pathogen/causative agent
– Different strains (if applicable)
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Type of pathogen
Method of transmission
Incubation Period
Site of Action of Pathogen
Global Distribution
Method of Diagnosis
Signs and Symptoms (Clinical Features)
Method of Diagnosis
Treatments
Prevention
Control Efforts of the Disease
Annual Incidence Worldwide
Annual Mortality World Wide
Global Distribution
Extra information Relevant to Infectious Disease
• Team Session: 10 minutes
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Disease JigSaw
Meet with your team
Select team leader
Team leader needs to record the name of each team member and the disease they are covering
Team needs to discuss how they will record/share information when they return from their breakout session
• Breakout sessions: 25 minutes
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All the 1’s, 2’s, 3’s, 4’s, and 5’s will meet together at assigned locations
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6.
Table 1
Hallway by front door of classroom
Hallway by back door of classroom
Table 3
Table 5
Front of classroom (desks)
– Use various resources; PRIMARY resource is textbook, but you should also use the
revision guide, internet, etc.
– Figure out the fast strategy to gather the information about the disease within your
group
• Team Session Part 2: minutes
– Each member needs to “TEACH” their other team members about the infectious disease they
became an expert in
– You will be graded by your team members on how well you present the information to them!