Download L11 Transmission of infectious diseases

INFECTIOUS DISEASE – A DISEASE THAT IS
CAPABLE OF BEING TRANSMITTED FROM
ONE PERSON TO ANOTHER BY DIRECT OR
INDIRECT CONTACT
NOW THINK OF AS MANY METHODS OF
TRANSMISSION BETWEEN ONE PERSON AND ANOTHER
Immune system
diseases
Non specific
immunity
Disease survival
mechanisms
Physical &
chemical barriers
Infectious
Disease
Inflammatory
Non-specific
Cellular response
Specific
immunity
Transmission
Epidemiology
Vaccination
Public Health
Immunological
surveillance
T cells
B cells
Clonal Selection
theory
BIG PICTURE
INFECTIOUS DISEASES ARE TRANSMITTED BY;
- DIRECT PHYSICAL CONTACT (HANDS SHAKING)
- WATER (CONTAMINATED BY MICRO-ORGANISM)
- FOOD (CONTAMINATED – COMMON FAECAL-ORAL ROUTE)
- BODY FLUIDS (SALIVA/BLOOD OR SEMINAL FLUIDS (OR NEEDLE SHARE)
- INHALED AIR (DROPLETS IN AIR, SNEEZING/COUGHING)
- VECTOR ORGANISMS (MOSQUITOES / FLEAS)
- INDIRECT PHYSICAL CONTACT (CUP/ DOOR HANDLE/ NEEDLE)
LEARNING OUTCOMES
• IDENTIFY THE TRANSMISSION METHODS FOR
INFECTIOUS DISEASES
• DEVISE METHODS OF CONTROLLING DISEASE
THROUGH TRANSMISSION
• START TO EXAMINE WHY THIS AREA IS IMPORTANT
AND LOOK AT EPIDEMIOLOGY (LOCATION / SPREAD
AND DISTRIBUTION OF DISEASE)
MAIN CULPRITS OF DISEASE ......
HOT question
Multicellular parasites
MORE ON THESE NEXT TIME ... BUT HOW TO STOP THEM?
WRITE THEM ON A MULTI-CAUSE MAP
CONTROL OF
TRANSMISSION
COMMUNITY RESPONSIBILITY
INDIVIDUAL RESPONSIBILITY
LEGAL
HOW TO STOP THEM?
Clue – think
about Rabies
Clue – to work in
MacDonalds what
do you need to
complete?
Clue – how do you prevent STI?
Clue – what do
hospitals do ?
Clue – what does
the council do once
a week? Why pay
water rates?
Clue – what
should you
do after the
toilet?
EPIDEMIOLOGY OF INFECTIOUS DISEASE
EPIDEMIOLOGISTS STUDY THE OUTBREAK AND PATTERN OF INFECTIOUS
DISEASES TO DETERMINE THE FACTORS WHICH AFFECT THE SPREAD OF
INFECTIOUS DISEASE.
Spread
pattern of
disease
Sporadic
Description
WHO – classify
as 6 stages –
not including the
first two .....
Occurs in scattered or isolated instances with no connection
between them. Occasional occurrence.
Endemic
Recurs as a regular number of cases in a particular area.
Regular cases occurring in an area
Epidemic
Simultaneously affects an unusually large number of
people in a particular area. Unusual high number of cases
in an area
Pandemic
Occurs as a series of epidemics that spreads across whole
continents or even throughout world, a global epidemic
PHASE 1: NO INFECTIONS IN HUMANS
ARE BEING CAUSED BY VIRUSES
CIRCULATING IN ANIMALS.
PHASE 2: PATHOGEN CAUSES SPORADIC
INFECTION IN HUMANS, AND IS A POTENTIAL
PANDEMIC THREAT. ZOONOTIC JUMP
PHASE 3: FLU CAUSES SPORADIC CASES
IN PEOPLE, BUT NO SIGNIFICANT HUMANTO-HUMAN TRANSMISSION.
PHASE 4: HUMAN-TO-HUMAN
TRANSMISSION AND COMMUNITY-LEVEL
OUTBREAKS, ENDEMIC TO AREA
PHASE 5: HUMAN-TO-HUMAN
TRANSMISSION IN AT LEAST TWO
COUNTRIES / TWO AREAS. EPIDEMIC
STRONG SIGNAL PANDEMIC IMMINENT.
PHASE 6: PATHOGEN SPREADS TO ANOTHER
COUNTRY IN A DIFFERENT REGION/
SPREADING ACROSS CONTINENT. GLOBAL
PANDEMIC UNDER WAY.
POST-PEAK: PANDEMIC ACTIVITY APPEARS
TO BE DECREASING THOUGH SECOND
WAVE POSSIBLE.
POST-PANDEMIC: ACTIVITY RETURNS TO
NORMAL, SEASONAL PATHOGEN LEVELS.
PREVIOUS PANDEMICS .....
• PLAGUE OF ATHENS – TYPHOID FEVER
• ANTOINE PLAGUE – SMALLPOX
• BLACK DEATH – BUBONIC PLAGUE
• SECOND CHOLERA PANDEMIC - CHOLERA
• SPANISH FLU - INFLUENZA
POTENTIAL PANDEMICS .....
• SARS
• SWINE FLU
• AVIAN (BIRD) FLU
• H1N1
PUBLIC HEALTH
DUE TO ITS ROLE IN MAINTAINING HEALTH AND
COMBATING INFECTIOUS DISEASES ON A GLOBAL
LEVEL, THE IMMUNE SYSTEM IS AT THE CENTRE OF
MUCH OF THE RESEARCH IN PUBLIC HEALTH.
WORLD HEALTH
ORGANISATION
(WHO) MONITOR AND
TRACK POTENTIAL
THREATS
BBC HORIZON - http://www.youtube.com/watch?v=dxk1DI2qX5E
http://www.youtube.com/watch?v=V_-X0qWltQw
http://www.youtube.com/watch?v=hTmw2Y5iA-k
INCREASED POTENTIAL PROBLEMS AND
CONTROL MEASURES ...
GLOBAL TRAVEL / IMMIGRATION MEANS
TRANSMISSION MORE LIKELY ACROSS CONTINENTS.
BASED ON EPIDEMIOLOGICAL STUDIES CONTROL
MEASURES CAN BE CONSIDERED THAT INCLUDE;
1.
PREVENTING TRANSMISSION (TODAY)
2.
DRUG THERAPY (NEXT SLIDE)
3.
IMMUNISATION (TWO LESSON TIMES)
OR A COMBINATION OF THESE.
DEMONSTRATE YOUR UNDERSTANDING
• DATA HANDLING SKILLS ....
DRUG THERAPY;
PREVENTION CASE - TAMIFLU
• BROUGHT OUT VERY QUICKLY BY PHARMACEUTICALS IN RESPONSE
TO THE POTENTIAL PANDEMIC OF FLU
• METHOD OF ACTION IS INHIBITION
OF AN ENZYME (NEURAMINIDASE)
WHICH CLEAVES IT OUT OF CELL