Transcript USVmain em and reem inf dis

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CHP400
COMMUNITY HEALTH PROGRAM-II
Mohamed M. B. Alnoor
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Emerging and Re-emerging
Infectious Diseases
Contents
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• Definitions
• Emerging Infections since 1973
• Major factors contributing to the
emergence of infectious diseases
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Emerging and Re-emerging
Infectious Diseases
Definitions
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 Emerging Infectious Diseases
“New,
reemerging
or drug-resistant infections
whose incidence in humans
has increased
in the past two decades
or threatens to increase
in the near future.”
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Emerging and Re-emerging
Infectious Diseases
Definitions
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 Emerging Infectious Diseases
 Emerging/New
Newly appeared in a population.
Re-emerging/Resurging
Incidence increased over20 years or
threatens to increase soon.
Deliberately emerging:
Developed for nefarious use
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Emerging and Re-emerging
Infectious Diseases
W H Y ?????
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After great advances
in medical research,
antimicrobial drug discovery,
technology development,
improvement in sanitation..
WHY are microbes still posing
such a problem!!??
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‫‪Emerging and Re-emerging‬‬
‫‪Infectious Diseases‬‬
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‫‪Major Factors Contributing to the‬‬
‫‪Emergence of Infectious Diseases‬‬
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‫قال رسول هللا لى هللا ليه و م‪ « :‬م هر ا فاحشة في قوم قط‬
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‫حتى نوا بها إال فشا م الطاعون واألوجاع ا تي م كن ضت في‬
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‫رواه اين ماجه والحا مك‬
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‫أسال م الذين ضوا ‪».‬‬
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
1. Ecological changes & agricultural
development
2. Human demographics and behavior
3. Technology and industry
4. Economic development and land use
5. International travel and commerce
6. Microbial adaptation and change
7. Breakdown of public health measures
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Emerging and Re-emerging
Infectious Diseases
More Factors Contributing to the
Emergence of Infectious Diseases
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8. Human vulnerability
9. Climate and weather
10. Poverty and social inequality
11. War and famine
12. Lack of political will
13. Intent to harm
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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1. Ecology & agriculture
Placing people in contact with a
reservoir of an infection (zoonotic or
arthropod-borne) either by:
- Increasing proximity
- Changing conditions
microbe
natural host
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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1. Ecology & agriculture
Reforestation in USA
Increased the number of deer & deer ticks
Increased
Human
contact with
deers
Deer tick
Human affection by Lyme disease
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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1. Ecology & agriculture
Conversion of grassland to
maise cultivation
Rodents & people
come together
Rodent
Argentine Haemorrhagic fever in
humans
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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1. Ecology & agriculture
Pig Farm
China
Duck farm
Mixing vessels
Influenza
Influenza
Influenza
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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1. Ecology & agriculture
Increased Rice cultivation in
South East Asia.
Field mouse
Increased human contact with Field mouse
Introduction of Korean haemorrhagic fever
in Humans
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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2. Human demographics and behavior
Inflation of population size
Insufficient infrastructures
Use open containers for water
Breading mosquitos
Dengue fever in Asia
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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2. Human demographics and behavior
Urbanization
• More people concentrated in cities-often
without adequate infrastructure
• Increases in the elderly populations
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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2. Human demographics and behavior
Urbanization
• Increases in children in daycare:
working woman with kids
under 5 was 30% in 1970,
became 75% in 2000.
• Fast paced Lifestyles- increase in
convenience items and more stress.
• High-risk behavior- Drug use and
unprotected sex
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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3. Technology and industry
• Modern mass production increases the
chance of accidental contamination and
amplifies the effect of such contamination.
-Contamination of hamburger meat by
E.coli strains causing haemolytic uraemic
syndrome.
-Feeding cattle by byproducts of sheep
causing bovine spongiform encephalitis.
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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3. Technology and industry
• New diagnostics lead to identification of
previously unknown microbes for known
diseases e.g. Helicobacter pylori and
peptic ulcer.
• Medical technology
- People living longer, but have weaker
immune systems.
- Blood & organ transplantation transmit
infections.
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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4. Economic development and land use
• Changing ecology influencing
waterborne, vectorborne disease
transmission (e.g. dams, deforestation)
• More exposure to wild animals and
vectors (Lyme disease, ehrlichiosis,
babesiosis, HPS,…)
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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5. International travel and commerce
• Circumnavigation: 365 days, now 36 hours
• International travelers: 400 millions
• Increased incidence of both Tuberculosis
and Influenza transmission on long flights
• Transportation of products
- Rapid transport of disease harboring
fresh products.
- Transport of livestock facilitates transport
of viruses and arthropods (esp. ticks)
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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5. International travel and commerce
• Travel and HIV/AIDS.
• Cholera and Hajj.
• Historically:
- Silk route and plague.
- Slaves trade and yellow fever.
- Migration to new world and smallpox.
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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6. Microbial adaptation and change
• Lateral transfer is common: shown by
genome sequencing.
• Rapid adaptation: due to high mutation
rates in RNA viruses.
• Rapid build up of rare mutations: because
of quick reproduction
• Resistance: Antimicrobials used in livestock
growth enhancement and over-prescription
of antimicrobials by doctors.
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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7. Breakdown of public health measures
• Decrease in chlorine in water supplies
lead to rapid spread of cholera in South
America.
• Non functioning water plant in
Wisconsin, USA lead to outbreak of
waterborne cryptosporidium
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Emerging and Re-emerging
Infectious Diseases
Major Factors Contributing to the
Emergence of Infectious Diseases
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7. Breakdown of public health measures
• Inadequate vaccinations and Diphtheria
in former USSR independent countries.
• Discontinued mosquito control efforts
and dengue and re-emergence of
malaria.
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Emerging and Re-emerging
Infectious Diseases
Summary
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• Infectious diseases will always be
there
• New infectious diseases will always
occur
• Man and his behavior are the main
reasons