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Title: Communicable Diseases, Nosocomial Diseases, Emerging and ReEmerging Diseases


1
Communicable Diseases, Nosocomial Diseases,
Emerging and Re-Emerging Diseases
  • Biology 447 - Environmental Microbiology

2
Outline
  • Communicable Diseases
  • Nosocomial Infections (hospital-acquired)?
  • Antibiotic Resistance
  • Bioterrorism Agents
  • Mapping Emerging Diseases
  • Neglected Diseases
  • Emerging Diseases in the US
  • Diseases preventable by vaccination
  • Global Emerging and Re-emerging Diseases
  • - HIV - Hepatitis - Influenza
  • - Malaria - Herpes
    - Ebola
  • - Tuberculosis - HPV - SARS
  • - Avian Influenza - West Nile virus -
    Trypanosomiasis
  • - Others
  • Summary

3
  • Communicable Diseases

4
  • Introduction

5
  • In 2001, a review of the scientific literature
    identified 1415 species of infectious organisms
    known to be pathogenic to humans, including
  • 217 viruses and prions,
  • 538 bacteria and rickettsiae,
  • 307 fungi,
  • 66 protozoa and
  • 287 helminths.
  • Of these, 61 were zoonotic and 12 were
    associated with diseases considered to be
    emerging
  • (Taylor, Latham Woolhouse, 2001).

6
(No Transcript)
7
Communicable Diseases Definition
  • Defined as
  • any condition which is transmitted directly or
    indirectly to a person from an infected person or
    animal through the agency of an intermediate
    animal, host, or vector, or through the inanimate
    environment.
  • Transmission is facilitated by the following
  • more frequent human contact due to
  • Increase in the volume and means of
    transportation (affordable international air
    travel),
  • globalization (increased trade and contact)?
  • Microbial adaptation and change
  • Breakdown of public health capacity at various
    levels
  • Change in human demographics and behavior
  • Economic development and land use patterns

8
CD- Modes of transmission
  • Direct
  • Blood-borne or sexual HIV, Hepatitis B,C
  • Inhalation Tuberculosis, influenza, anthrax
  • Food-borne E.coli, Salmonella,
  • Contaminated water- Cholera, rotavirus, Hepatitis
    A
  • Indirect
  • Vector-borne- malaria, onchocerciasis,
    trypanosomiasis
  • Formites
  • Zoonotic diseases animal handling and feeding
    practices (Mad cow disease, Avian Influenza)
  • Nosocomial Infections- physician or health care
    worker induced diseases

9
Importance of Communicable Diseases
  • Significant burden of disease especially in low
    and middle income countries
  • Social impact
  • Economic impact
  • Potential for rapid spread
  • Human security concerns
  • Intentional use

10
Communicable Diseases account for a significant
global disease burden
  • In 2005, CDs accounted for about 30 of the
    global Burden of Disease and 60 of the BoD in
    Africa.
  • CDs typically affect LIC and MICs
    disproportionately.
  • Account for 40 of the disease burden in low and
    middle income countries
  • Most communicable diseases are preventable or
    treatable.

11
Communicable Disease Burden Varies Widely Among
Continents
12
Communicable Disease Burden Varies Widely Among
Continents
67
13
Communicable disease burden in Europe
14
Communicable disease burden in Europe
3
15
Causes of Death Vary Greatly by Country Income
Level
Sierra Leone - Age distribution at death (2005)?
Denmark - Age distribution at death (2005)?
16
CDs have a significant social impact
  • Disruption of family and social networks
  • Child-headed households, social exclusion
  • Widespread stigma and discrimination
  • TB, HIV/AIDS, Leprosy
  • Discrimination in employment, schools, migration
    policies
  • Orphans and vulnerable children
  • Loss of primary care givers
  • Susceptibility to exploitation and trafficking
  • Interventions such as quarantine measures may
    aggravate the social disruption

17
CDs have a significant economic impact in
affected countries
  • At the macro level
  • Reduction in revenue for the country (e.g.
    tourism)?
  • Estimated cost of SARS epidemic to Asian
    countries 20 billion (2003) or 2 million per
    case.
  • Drop in international travel to affected
    countries by 50-70
  • Malaria causes an average loss of 1.3 annual GDP
    in countries with intense transmission
  • The plague outbreak in India cost the economy
    over 1 billion from travel restrictions and
    embargoes
  • At the household level
  • Poorer households are disproportionately affected
  • Substantial loss in productivity and income for
    the infirmed and caregiver
  • Catastrophic costs of treating illness

18
International boundaries are disappearing
  • Borders are not very effective at stopping
    communicable diseases
  • With increasing globalization
  • interdependence of countries more trade and
    human/animal interactions
  • The rise in international traffic and commerce
    makes challenges even more daunting
  • Other global issues affect or are affected by
    communicable diseases.
  • climate change
  • migration
  • Change in biodiversity

19
Human Security concerns
  • Potential magnitude and rapid spread of
    outbreaks/pandemics. e.g. SARS outbreak
  • No country or region can contain a full blown
    outbreak of Avian influenza
  • Bioterrorism and intentional outbreaks
  • Anthrax, Small pox
  • New and re-emerging diseases
  • Ebola, TB (MDR-TB and XDR-TB), Hantvirus, etc

20
  • Nosocomial Infections

21
Nosocomial Infection
Any infection that is acquired from being in a
hospital or other healthcare institution (e.g.,
nursing home)?
22
  • 44,000 - 98,000 preventable deaths occur in U.S.
    hospitals every year
  • 17-29 billion healthcare dollars wasted because
    of medical errors

23
Burden of Nosocomial Infection in U.S. Hospitals
  • 1.7 - 2 million nosocomial infections/year
  • Results in 80,000-100,000 deaths/year
  • Medication errors cause 7,000 deaths
  • Cost 5-6 billion dollars/year

24
Emerging Drug Resistance in Bacteria
  • MRSA Methicillin-Resistant Staphylococcus
    aureus
  • VRE Vancomycin-resistant enterococcus
  • 3CRKP Klebsiella pneumoniae resistant to 3rd
    generation cepalosporins
  • FQRPA Pseudomonas aeruginosa resistant to
    fluoroquinolones
  • Clostridium difficile (NAP1) resistant to
    fluoroquinolones

25
  • Methicillin-Resistant Staphylococcus aureus
    (MRSA)?
  • Staphylococcus aureus is commonly carried on the
    skin or in the nose of healthy people.
    Approximately 25 to 30 of the population is
    colonized (when bacteria are present, but not
    causing an infection) in the nose.
  • It is one of the most common causes of skin
    infections but most of are minor (such as pimples
    and boils) and can be treated without
    antibiotics. It also can cause serious infections
    (such as surgical wound infections, bloodstream
    infections, and pneumonia).
  • Who is susceptible to MRSA infection?
  • MRSA usually infects hospital patients who are
    elderly or very ill. You may be at more risk if
    you have had frequent, long-term, or intensive
    use of antibiotics. Intravenous drug users and
    persons with long-term illnesses or who are
    immuno-suppressed are also at increased risk.
  • The infection can develop in an open wound such
    as a bedsore or when there is a tube such as a
    urinary catheter that enters the body. MRSA
    rarely infects healthy people.

26
  • Methicillin-Resistant Staphylococcus aureus
    (MRSA)?
  • Staphylococcus aureus is commonly carried on the
    skin or in the nose of healthy people.
    Approximately 25 to 30 of the population is
    colonized (when bacteria are present, but not
    causing an infection) in the nose.
  • It is one of the most common causes of skin
    infections but most of are minor (such as pimples
    and boils) and can be treated without
    antibiotics. It also can cause serious infections
    (such as surgical wound infections, bloodstream
    infections, and pneumonia).
  • Who is susceptible to MRSA infection?
  • MRSA usually infects hospital patients who are
    elderly or very ill. You may be at more risk if
    you have had frequent, long-term, or intensive
    use of antibiotics. Intravenous drug users and
    persons with long-term illnesses or who are
    immuno-suppressed are also at increased risk.
  • The infection can develop in an open wound such
    as a bedsore or when there is a tube such as a
    urinary catheter that enters the body. MRSA
    rarely infects healthy people.

27
Note
  • Staphylococcus aureus and MRSA can also cause
    illness in persons outside of hospitals and
    healthcare facilities.
  • MRSA infections that are acquired by persons who
    have not been recently (within the past year)
    hospitalized or had a medical procedure (such as
    dialysis, surgery, catheters) are know as
    Community-Acquired-MRSA infections (CA-MRSA
  • Data from a prospective study in 2003, suggests
    that 12 of clinical MRSA infections are
    community-associated, but this varies by
    geographic region and population.
  • CDC has investigated clusters of CA-MRSA skin
    infections among athletes, military recruits,
    children, Pacific Islanders, Alaskan Natives,
    Native Americans, men who have sex with men, and
    prisoners.Factors that have been associated with
    the spread of MRSA skin infections include close
    skin-to-skin contact, openings in the skin such
    as cuts or abrasions, contaminated items and
    surfaces, crowded living conditions, and poor
    hygiene.

28
Note
  • Staphylococcus aureus and MRSA can also cause
    illness in persons outside of hospitals and
    healthcare facilities.
  • MRSA infections that are acquired by persons who
    have not been recently (within the past year)
    hospitalized or had a medical procedure (such as
    dialysis, surgery, catheters) are know as
    Community-Acquired-MRSA infections (CA-MRSA
  • Data from a prospective study in 2003, suggests
    that 12 of clinical MRSA infections are
    community-associated, but this varies by
    geographic region and population.
  • CDC has investigated clusters of CA-MRSA skin
    infections among athletes, military recruits,
    children, Pacific Islanders, Alaskan Natives,
    Native Americans, men who have sex with men, and
    prisoners.Factors that have been associated with
    the spread of MRSA skin infections include close
    skin-to-skin contact, openings in the skin such
    as cuts or abrasions, contaminated items and
    surfaces, crowded living conditions, and poor
    hygiene.

29
Staphylococcus aureus growth
30
Vancomycin-resistant enterococci
  • Enteroccocci are bacteria that are normally
    present in the human intestines and in the female
    genital tract and are often found in the
    environment. These bacteria can sometimes cause
    infections.
  • Vancomycin is an antibiotic that is often used to
    treat infections caused by enterococci. In some
    instances, enterococci have become resistant to
    this drug and thus are called vancomycin-resistant
    enterococci (VRE). Most VRE infections occur in
    hospitals.
  • In the last decade enterococci have become
    recognized as leading causes of nosocomial
    bacteremia, surgical wound infection, and urinary
    tract infection
  • Enterococci are readily recovered outdoors from
    vegetation and surface water, probably because of
    contamination by animal excrement or untreated
    sewage. In humans, typical concentrations of
    enterococci in stool are up to 108 CFU per gram

31
Vancomycin-resistant enterococci
  • Enteroccocci are bacteria that are normally
    present in the human intestines and in the female
    genital tract and are often found in the
    environment. These bacteria can sometimes cause
    infections.
  • Vancomycin is an antibiotic that is often used to
    treat infections caused by enterococci. In some
    instances, enterococci have become resistant to
    this drug and thus are called vancomycin-resistant
    enterococci (VRE). Most VRE infections occur in
    hospitals.
  • In the last decade enterococci have become
    recognized as leading causes of nosocomial
    bacteremia, surgical wound infection, and urinary
    tract infection
  • Enterococci are readily recovered outdoors from
    vegetation and surface water, probably because of
    contamination by animal excrement or untreated
    sewage. In humans, typical concentrations of
    enterococci in stool are up to 108 CFU per gram

32
Vancomycin-resistant enterococci
  • Enteroccocci are bacteria that are normally
    present in the human intestines and in the female
    genital tract and are often found in the
    environment. These bacteria can sometimes cause
    infections.
  • Vancomycin is an antibiotic that is often used to
    treat infections caused by enterococci. In some
    instances, enterococci have become resistant to
    this drug and thus are called vancomycin-resistant
    enterococci (VRE). Most VRE infections occur in
    hospitals.
  • In the last decade enterococci have become
    recognized as leading causes of nosocomial
    bacteremia, surgical wound infection, and urinary
    tract infection
  • Enterococci are readily recovered outdoors from
    vegetation and surface water, probably because of
    contamination by animal excrement or untreated
    sewage. In humans, typical concentrations of
    enterococci in stool are up to 108 CFU per gram

33
  • Among several phenotypes for vancomycin-resistant
    enterococci, VanA (resistance to vancomycin and
    teicoplanin) and VanB (resistance to vancomycin
    alone) are most common.
  • In the United States, VanA and VanB account for
    approximately 60 and 40 of vancomycin-resistant
    enterococci (VRE) isolates, respectively.
  • Enterococci are intrinsically resistant to many
    antibiotics. Unlike acquired resistance and
    virulence traits, which are usually transposon or
    plasmid encoded, intrinsic resistance is based in
    chromosomal genes, which typically are
    nontransferrable

34
CDCs National Nosocomial Infection Surveillance
(NNIS) System, 1989 - 2004
MRSA methicillin-resistant Staphylococcus
aureus VRE vancomycin-resistant
enterococcus
FQRPA Pseudomonas aeruginosa resistant to
fluoroquinolones 3CRKP Klebsiella
pneumoniae resistant to 3rd generation
cephalosporins
35
3CRKP and FQRPA
36
Clostridium difficile (NAP1)?
37
  • Potential Bioterrorism Agents

38
Complete List of Potential Bioterrorism Agents
from the Center for Disease Control, Atlanta,
Georgia, USA From http//emergency.cdc.gov/agen
t/agentlist.asp
  • Anthrax (Bacillus anthracis)?
  • Arenaviruses
  • Bacillus anthracis (anthrax)?
  • Botulism (Clostridium botulinum toxin)?
  • Brucella species (brucellosis)?
  • Brucellosis (Brucella species)?
  • Burkholderia mallei (glanders)?
  • Burkholderia pseudomallei (melioidosis)?
  • Chlamydia psittaci (psittacosis)?
  • Cholera (Vibrio cholerae)?
  • Clostridium botulinum toxin (botulism)?
  • Clostridium perfringens (Epsilon toxin)?
  • Coxiella burnetii (Q fever)?
  • Ebola virus hemorrhagic fever
  • E. coli O157H7 (Escherichia coli)?
  • Emerging infectious diseases such as Nipah virus
    and hantavirus
  • Epsilon toxin of Clostridium perfringens

39
Complete List of Potential Bioterrorism Agents
from the CDC
  • Escherichia coli O157H7 (E. coli)?
  • Food safety threats (e.g., Salmonella species,
    Escherichia coli O157H7, Shigella)?
  • Francisella tularensis (tularemia)?
  • Glanders (Burkholderia mallei)?
  • Lassa fever
  • Marburg virus hemorrhagic fever
  • Melioidosis (Burkholderia pseudomallei)?
  • Plague (Yersinia pestis)?
  • Psittacosis (Chlamydia psittaci)?
  • Q fever (Coxiella burnetii)?
  • Ricin toxin from Ricinus communis (castor beans)?
  • Rickettsia prowazekii (typhus fever)?
  • Salmonella species (salmonellosis)?
  • Salmonella Typhi (typhoid fever)?
  • Salmonellosis (Salmonella species)?

40
Complete List of Potential Bioterrorism Agents
from the CDC
  • Shigella (shigellosis)?
  • Shigellosis (Shigella)?
  • Smallpox (variola major)?
  • Staphylococcal enterotoxin B
  • Tularemia (Francisella tularensis)?
  • Typhoid fever (Salmonella Typhi)?
  • Typhus fever (Rickettsia prowazekii)?
  • Variola major (smallpox)?
  • Vibrio cholerae (cholera)?
  • Viral encephalitis (alphaviruses e.g.,
    Venezuelan equine encephalitis, eastern equine
    encephalitis, western equine encephalitis)?
  • Viral hemorrhagic fevers (filoviruses e.g.,
    Ebola, Marburg and arenaviruses e.g., Lassa,
    Machupo)?
  • Water safety threats (e.g., Vibrio cholerae,
    Cryptosporidium parvum)?
  • Yersinia pestis (plague)?

41
Complete list of potential bioterrorism agents
(CDC)?
  • Anthrax (Bacillus anthracis)?
  • Arenavirues
  • Bacillus anthracis (anthrax)?
  • Botulism (Clostridium botulinum toxin)?
  • Brucella species (brucellosis)?
  • Brucellosis (Brucella species)?
  • Burkholderia mallei (glanders)?
  • Burkholderia pseudomallei (melioidosis)?
  • Chlamydia psittaci (psittacosis)?
  • Cholera (Vibrio cholerae)?
  • Clostridium botulinum toxin (botulism)?
  • Clostridium perfringens (Epsilon toxin)?
  • Coxiella burnetii (Q fever)?
  • Ebola virus hemorrhagic fever
  • E. coli O157H7 (Escherichia coli)?
  • Emerging infectious diseases such as Nipah virus
    and hantavirus
  • Epsilon toxin of Clostridium perfringens
  • Escherichia coli O157H7 (E. coli)?
  • Food safety threats (e.g., Salmonella
    species,scherichia coli O157H7, Shigella)?
  • Plague (Yersinia pestis)?
  • Psittacosis (Chlamydia psittaci)?
  • Q fever (Coxiella burnetii)?
  • Ricin toxin from Ricinus communis (castor beans)?
  • Rickettsia prowazekii (typhus fever)?
  • Salmonella species (salmonellosis)?
  • Salmonella Typhi (typhoid fever)?
  • Salmonellosis (Salmonella species)?
  • Shigella (shigellosis)?
  • Shigellosis (Shigella)?
  • Smallpox (variola major)?
  • Staphylococcal enterotoxin
  • Tularemia (Francisella tularensis)?
  • Typhoid fever (Salmonella Typhi)?
  • Typhus fever (Rickettsia prowazekii)?
  • Variola major (smallpox)?
  • Vibrio cholerae (cholera)?
  • Viral encephalitis (alphaviruses e.g.,
    Venezuelan equine encephalitis, eastern equine
    encephalitis, western equine encephalitis)?
  • Viral hemorrhagic fevers (filoviruses e.g.,
    Ebola, Marburg and arenaviruses e.g., Lassa,
    Machupo)?

42
  • Neglected Diseases

43
Neglected diseases
  • Cause over 500,000 deaths and 57 million DALYs
    annually.
  • Include the following
  • Helminthic infections
  • Hookworm (Ascaris, trichuris), lymphatic
    filariasis, onchocerciasis, schistosomiasis,
    dracunculiasis
  • Protozoan infections
  • Leishmaniasis, African trypanosomiasis, Chagas
    disease
  • Bacterial infections
  • Leprosy, trachoma, buruli ulcer

44
  • Mapping Emerging Diseases

45
  • Emerging diseases on rise
    Date 21/02/2008
  • An international research team has provided the
    first scientific evidence that deadly emerging
    diseases have risen steeply across the world, and
    has mapped the outbreaks' main sources.
  • They say new diseases originating from wild
    animals in poor nations are the greatest threat
    to humans.
  • Expansion of humans into shrinking pockets of
    biodiversity and resulting contacts with wildlife
    are the reason, they say. Meanwhile, richer
    nations are nursing other outbreaks, including
    multidrug-resistant pathogen strains, through
    overuse of antibiotics, centralised food
    processing and other technologies.
  • The study appears in the Feb. 21 2008 issue of
    the leading scientific journal Nature. Emerging
    diseases-defined as newly identified pathogens,
    or old ones moving to new regions--have caused
    devastating outbreaks already.
  • The HIV/AIDS pandemic, thought to have started
    from human contact with chimps, has led to over
    65 million infections recent outbreaks of SARS
    originating in Chinese bats have cost up to 100
    billion. Outbreaks like the exotic African Ebola
    virus have been small, but deadly.

46
  • Emerging diseases on rise
    Date 21/02/2008
  • An international research team has provided the
    first scientific evidence that deadly emerging
    diseases have risen steeply across the world, and
    has mapped the outbreaks' main sources.
  • They say new diseases originating from wild
    animals in poor nations are the greatest threat
    to humans.
  • Expansion of humans into shrinking pockets of
    biodiversity and resulting contacts with wildlife
    are the reason, they say. Meanwhile, richer
    nations are nursing other outbreaks, including
    multidrug-resistant pathogen strains, through
    overuse of antibiotics, centralised food
    processing and other technologies.
  • The study appears in the Feb. 21 2008 issue of
    the leading scientific journal Nature. Emerging
    diseases (defined as newly identified pathogens,
    or old ones moving to new regions) have caused
    devastating outbreaks already.
  • The HIV/AIDS pandemic, thought to have started
    from human contact with chimps, has led to over
    65 million infections recent outbreaks of SARS
    originating in Chinese bats have cost up to 100
    billion. Outbreaks like the exotic African Ebola
    virus have been small, but deadly.

47
  • Despite three decades of research, previous
    attempts to explain these seemingly random
    emergences were unsuccessful.
  • In the new study, researchers from four
    institutions analysed 335 emerging diseases from
    1940 to 2004, then converted the results into
    maps correlated with human population density,
    population changes, latitude, rainfall and
    wildlife biodiversity.
  • They showed that disease emergences have roughly
    quadrupled over the past 50 years. Some 60 of
    the diseases travelled from animals to humans
    (such diseases are called zoonoses) and the
    majority of those came from wild creatures.
  • With data corrected for lesser surveillance done
    in poorer countries, "hot spots" jump out in
    areas spanning sub-Saharan Africa, India and
    China smaller spots appear in Europe, and North
    and South America.

48
  • Despite three decades of research, previous
    attempts to explain these seemingly random
    emergences were unsuccessful.
  • In the new study, researchers from four
    institutions analysed 335 emerging diseases from
    1940 to 2004, then converted the results into
    maps correlated with human population density,
    population changes, latitude, rainfall and
    wildlife biodiversity.
  • They showed that disease emergences have roughly
    quadrupled over the past 50 years. Some 60 of
    the diseases travelled from animals to humans
    (such diseases are called zoonoses) and the
    majority of those came from wild creatures.
  • With data corrected for lesser surveillance done
    in poorer countries, "hot spots" jump out in
    areas spanning sub-Saharan Africa, India and
    China smaller spots appear in Europe, and North
    and South America.

49
  • Emerging diseases on rise - Date
    21/02/2008
  • "We are crowding wildlife into ever-smaller
    areas, and human population is increasing. The
    meeting of these two things is a recipe for
    something crossing over." - Marc Levy, a
    global-change expert at the Center for
    International Earth Science Information Network
    (CIESIN)?
  • The main sources are mammals.
  • Some pathogens may be picked up by hunting or
    accidental contact others, such as Malaysia's
    Nipah virus, go from wildlife to livestock, then
    to people.
  • Humans have evolved no resistance to zoonoses, so
    the diseases can be extraordinarily lethal. The
    scientists say that the more wild species in an
    area, the more pathogen varieties they may
    harbour.
  • About 20 percent of known emergences are
    multidrug-resistant strains of previously known
    pathogens, including tuberculosis.
  • Increasing use and reliance on modern antibiotics
    has helped breed such dangerous strains

50
  • Emerging diseases on rise - Date
    21/02/2008
  • "We are crowding wildlife into ever-smaller
    areas, and human population is increasing. The
    meeting of these two things is a recipe for
    something crossing over." - Marc Levy, a
    global-change expert at the Center for
    International Earth Science Information Network
    (CIESIN)?
  • The main sources are mammals.
  • Some pathogens may be picked up by hunting or
    accidental contact others, such as Malaysia's
    Nipah virus, go from wildlife to livestock, then
    to people.
  • Humans have evolved no resistance to zoonoses, so
    the diseases can be extraordinarily lethal. The
    scientists say that the more wild species in an
    area, the more pathogen varieties they may
    harbour.
  • About 20 percent of known emergences are
    multidrug-resistant strains of previously known
    pathogens, including tuberculosis.
  • Increasing use and reliance on modern antibiotics
    has helped breed such dangerous strains

51
  • Emerging diseases on rise
    Date 21/02/2008
  • More diseases emerged in the 1980s than any other
    decade-likely due to the HIV/AIDS pandemic, which
    led to other new diseases in immune-compromised
    victims.
  • In the 1990s, insect-transmitted diseases saw a
    peak, possibly in reaction to rapid climate
    changes that started taking hold then.
  • "The world's public-health resources are
    misallocated. Most are focused on richer
    countries that can afford surveillance, but most
    of the hotspots are in developing countries. If
    you look at the high-impact diseases of the
    future, we're missing the point."
  • "We need to start finding pathogens before they
    emerge," said Daszak.

52
  • Emerging diseases on rise
    Date 21/02/2008
  • More diseases emerged in the 1980s than any other
    decade-likely due to the HIV/AIDS pandemic, which
    led to other new diseases in immune-compromised
    victims.
  • In the 1990s, insect-transmitted diseases saw a
    peak, possibly in reaction to rapid climate
    changes that started taking hold then.
  • "The world's public-health resources are
    misallocated. Most are focused on richer
    countries that can afford surveillance, but most
    of the hotspots are in developing countries. If
    you look at the high-impact diseases of the
    future, we're missing the point."
  • "We need to start finding pathogens before they
    emerge," said Daszak.

53
  • Nature 451, 990-993 (21 February 2008)?
  • Global trends in emerging infectious diseases
  • Kate E. Jones, Nikkita G. Patel, Marc A. Levy,
    Adam Storeygard, Deborah Balk, John L. Gittleman
    Peter Daszak2
  • Institute of Zoology, Zoological Society of
    London, Regents Park, London NW1 4RY, UK
  • Consortium for Conservation Medicine, Wildlife
    Trust, 460 West 34th Street, 17th Floor, New
    York, New York 10001, USA
  • Center for International Earth Science
    Information Network, Earth Institute, Columbia
    University, 61 Route 9W, Palisades, New York
    10964, USA
  • Odum School of Ecology, University of Georgia,
    Athens, Georgia 30602, USA
  • Present addresses Department of Economics, Brown
    University, Providence, Rhode Island 02912, USA
    (A.S.) School of Public Affairs, Baruch College,
    City University of New York, 1 Bernard Baruch
    Way, Box D-0901, New York, New York 10010, USA
    (D.B.).

54
  • Nature 451, 990-993 (21 February 2008)?
  • Summary
  • Emerging infectious diseases (EIDs) are a
    significant burden on global economies and public
    health.
  • Their emergence is thought to be driven largely
    by socio-economic, environmental and ecological
    factors, but no comparative study has explicitly
    analysed these linkages to understand global
    temporal and spatial patterns of EIDs.
  • Here we analyse a database of 335 EID 'events'
    (origins of EIDs) between 1940 and 2004, and
    demonstrate non-random global patterns. EID
    events have risen significantly over time after
    controlling for reporting bias, with their peak
    incidence (in the 1980s) concomitant with the HIV
    pandemic. EID events are dominated by zoonoses
    (60.3 of EIDs) the majority of these (71.8)
    originate in wildlife (for example, severe acute
    respiratory virus, Ebola virus), and are
    increasing significantly over time.
  • We find that 54.3 of EID events are caused by
    bacteria or rickettsia, reflecting a large number
    of drug-resistant microbes in our database.
  • Our results confirm that EID origins are
    significantly correlated with socio-economic,
    environmental and ecological factors, and provide
    a basis for identifying regions where new EIDs
    are most likely to originate (emerging disease
    'hotspots').
  • They also reveal a substantial risk of wildlife
    zoonotic and vector-borne EIDs originating at
    lower latitudes where reporting effort is low. We
    conclude that global resources to counter disease
    emergence are poorly allocated, with the majority
    of the scientific and surveillance effort focused
    on countries from where the next important EID is
    least likely to originate.

55
Global distribution of relative risk of an EID
event
A
B
C
D
                                                  
                                         Caption 
Global distribution of relative risk of an EID
event. Maps are derived for EID events caused by
a, zoonotic pathogens from wildlife, b, zoonotic
pathogens from nonwildlife, c, drug-resistant
pathogens and d, vector-borne pathogens. The
relative risk is calculated from regression
coefficients and variable values in Table 1
(omitting the variable measuring reporting
effort), categorized by standard deviations from
the mean and mapped on a linear scale from green
(lower values) to red (higher values).

Credit Jones et. al., Nature
56
Geographic Origins of EID events from 1940 to 2004
Caption Global richness map of the geographic
origins of EID events from 1940 to 2004. The map
is derived for EID events caused by all pathogen
types. Circles represent one degree grid cells,
and the area of the circle is proportional to the
number of events in the cell. Credit Jones et.
al., Nature
Caption Global richness map of the geographic
origins of EID events from 1940 to 2004. The map
is derived for EID events caused by all pathogen
types. Circles represent one degree grid cells,
and the area of the circle is proportional to the
number of events in the cell. Credit Jones et.
al., Nature
57
  • Emerging Diseases in the United States

58
Emerging and re-emerging Diseases in the USA
Chlamydia Diphtheria Encephalitis West Nile
St. Louis E. coli N gonorrhea H. Influenzae
Hantavirus Hepatitis A-G (A and B)? Human
herpes viruses HHV 1-8 HIV/AIDS Human papilloma
viruses Influenza Emerging strains Legionella
pneumophila Lyme Disease
Measles Meningococcus MRSA Pertussis
Poliomyelitis Rabies Rocky Mountain Spotted
Fever Rubella SARS (Severe Acute Respiratory
Syndrome)? Salmonellosis Shigellosis
S. pneumoniae Syphilis Tetanus Toxic-Shock
Syndrome Tuberculosis
Vaccination possible
59
Emerging / Re-emerging Diseases - Continued
  • HIV/AIDS/Opportunistic infections
  • Hepatitis A-G, Other ?
  • Herpes, Flu, Other viral diseases
  • Candiaiasis, Other fungal diseases
  • Bacterial/Drug resistant bacterial
  • E. coli 015.7H7
  • Other food/H2O-borne
  • S. pneumonia, MRSA, VRSA
  • Vancomycin resistant Enterococcus (VRE)?
  • Multiple-drug resistant TB (MDRTB)?
  • Bio-engineered agents
  • Malaria drug-resistant

60
  • Why are these mainly older diseases
    re-emerging in the USA ?
  • Change in vaccination patterns and percentage
    coverage of population
  • Lack of herd immunity
  • New strains of organisms
  • Faster transmission
  • Hygiene and general health?
  • Overuse of antibiotics (in humans and animals)?
  • Immuno-compromised individuals (AIDS, cancer
    treatment patients, children, etc)?
  • Breakdown in public health or control
  • Human demographics, behaviour
  • Ecological changes

61
  • Why are these mainly older diseases
    re-emerging in the USA ?
  • Change in vaccination patterns and percentage
    coverage of population
  • Lack of herd immunity
  • New strains of organisms
  • Faster transmission
  • Hygiene and general health?
  • Overuse of antibiotics (in humans and animals)?
  • Immuno-compromised individuals (AIDS, cancer
    treatment patients, children, etc)?
  • Breakdown in public health or control
  • Human demographics, behaviour
  • Ecological changes

62
  • Why are these mainly older diseases
    re-emerging in the USA ?
  • Change in vaccination patterns and percentage
    coverage of population
  • Lack of herd immunity
  • New strains of organisms
  • Faster transmission
  • Hygiene and general health?
  • Overuse of antibiotics (in humans and animals)?
  • Immuno-compromised individuals (AIDS, cancer
    treatment patients, children, etc)?
  • Breakdown in public health or control
  • Human demographics, behaviour
  • Ecological changes

63
  • Diseases in the USA preventable by vaccination

64
Vaccine Preventable Diseases Adults
  • Mumps
  • Pneumococcus
  • Polio
  • Rubella
  • Tetanus
  • Varicella
  • Diphtheria
  • Hepatitis A
  • Hepatitis B
  • Influenza
  • Lyme Disease
  • Measles
  • Haemophilis influenza type B (Hib)?

www.cdc.gov, 2/4/2002
65
Vaccine Preventable Diseases - Adults -
Continued
  • Diphtheria
  • Hepatitis A
  • Hepatitis B
  • Influenza
  • Lyme Disease
  • Measles
  • Haemophilis influenza type B (Hib)
  • Mumps
  • Pneumococcus
  • Polio
  • Rubella
  • Tetanus
  • Varicella

66
Vaccine Preventable Diseases of children
  • Diphtheria
  • Hepatitis A
  • Hepatitis B
  • Pertussis
  • Measles
  • Haemophilis influenza type B (Hib)?

67
Vaccines for Potential Bioterrorism Agents
  • Anthrax
  • Cell-free culture of an avirulent,
    non-encapsulated,
    derivative of a bovine isolate-V770
  • 2-dose efficacy in monkeys
  • Estimated gt 90 effective against cutaneous
    anthrax
  • Botulism
  • Pentavalent toxoid (A-E)?
  • 3 doses 100 effacicious in primates
  • Tuleraemia
  • Live attenuated vaccine - 80 protection
  • Plague
  • Suspension of killed Yersinia pestis -
    Questionable immunity
  • Smallpox
  • Vaccinia vaccine Effective in one dose Side
    effects
  • Viral Hemorrhagic Fevers
  • No vaccine available

68
Increasing Antibiotic Resistance
69
  • Global Emerging and Re-emerging Diseases

70
Enlarged View on next 2 pages
71
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72
Continued
From WHO Emerging Issues in Water and
Infectious disease ISBN 92 4 159082 3 (LC/NLM
classification QW 80) ISSN 1728-2160
73
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74
  • Global Diseases

75
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76
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77
  • HIV/AIDS

78
Emerging viral diseases
  • AIDS
  • First reported 6/5/81 by CDC
  • Epidemiologic Notes and Reports
  • Pneumocystis Pneumonia --- Los Angeles
  • In the period October 1980-May 1981, 5 young men,
    all active
    homosexuals, were treated for biopsy-confirmed
    Pneumocystis carinii pneumonia at 3 different
    hospitals in Los Angeles, California. Two of the
    patients died. All 5 patients had
    laboratory-confirmed previous or current
    cytomegalovirus (CMV) infection and candidal
    mucosal infection.

79
  • 1982 Term AIDS replaces GRID
  • 1983 Universal precautions introduced
  • MMWR 198332101
  • The virus that causes AIDS identified
  • Gallo- HTLV III Montagnier-LAV
  • Name changed to human immunodeficiency virus
    (HIV)?
  • 1985 First serologic test for HIV licensed by
    FDA
  • Rock Hudson died of AIDS on 10/2/85
  • 1986 AZT approved by FDA
  • Record approval time of 6 months

80
HIV
  • Very dynamic virus
  • 109 viral particles/day
  • Loss of 108-109 CD4 cells/day
  • Replicate every two days
  • 680,000 viral particles produced and cleared
    daily
  • 95 of virus produced from newly infected cells

CD4 - A glycoprotein on the surface of helper T
cells that serves as a receptor for HIV. CD4 A
type of protein molecule in human blood that is
present on the surface of 65 of human T cells.
CD4 is a receptor for the HIV virus. When the HIV
virus infects cells with CD4 surface proteins, it
depletes the number of T cells, B cells, natural
killer cells, and monocytes in the patient's
blood. Most of the damage to an AIDS patient's
immune system is done by the virus' destruction
of CD4 lymphocytes. CD4 is sometimes called the
T4 antigen.
81
  • 1989 U.S. AIDS cases reported at 100,000
  • 1991 Estimated HIV infected in USA 1.5 million
  • Magic Johnson announces he is HIV positive
  • 1993 Multiple drugs fail in clinical trials
  • Period of extreme pessimism for HIV infected
  • 1995 First protease inhibitor approved
  • Inverase,saquinivir
  • HIV kinetics reported at 10 billion virions/day

82
  • 1996
  • HIV viral load testing
  • Becomes major method to assess ART
  • Mellors J Ann Intern Med 1997126946
  • ACTG 076 shows benefit of AZT in reducing
    perinatal transmission
  • NEJM 19963351621
  • Initial reports of benefit of HAART (highly
    active antiretroviral therapy )?
  • Ritonavir and indinavir approved
  • Fisrt NNRTI, nevirapine approved
  • First triple combination HAART study
  • Eradication of HIV might be possible with HAART
  • Dr. David Ho Time Man of the Year

83
  • 1997 13 decrease in AIDS deaths
  • 60-80 reduction in new AIDS-defining conditions,
    hospitalizations and deaths
  • Palella et al, NEJM 1998338853,
  • Mocroft at al, Lancet 19983521725
  • 1999 HIV spread to humans from chimpanzees
  • Occurred in Africa decades before recognition
    (maybe even longer)?
  • 2000 AIDS pandemic raging in Third World
  • 36.1 million people infected with HIV
  • 21.8 million deaths
  • 14,000-16,000 new infections/day
  • 2001 Two distinct epidemics

84
HIV Natural History
  • Clinical Latent Period
    Asymptomatic - May have PGL Viral
    set point at 6 month Equilibrium between
    immune system and HIV Persists for years
    Gradual, relentless degradation of immune
    function
  • Early Symptomatic HIV Infection
    CD4 lt 500
    Opportunistic Infection(s)?
  • AIDS CD4 lt 200 AIDS Defining Illness(s)
  • Advanced HIV Infection CD4 lt 50 Serious
    opportunistic Infection(s) Death

85
How Is HIV Spread?
  • Routes of Transmission
  • Sexual
  • Intravenous Drug Use
  • Inhalation drug abuse
  • Exposure to blood/blood products
  • Occupational exposure
  • Mother to child
  • Breast feeding

86
Mother-to-Child Transmission Global
Situation
  • Estimated 2.4 million HIV-positive women give

    birth annually to 600,000 HIV-positive babies
  • 1800 new infections each day
  • 90 in sub-Saharan Africa
  • lt1 (1000) in USA and Europe
  • Transmission rates
  • USA/Europe 1330 without ART,
    approaching 13 with ART
  • Developing countries 2043 without ART, lower
    rates with ART, even with short-course therapy
  • Breast feeding for 6 months
  • Additional 510 infections, with the highest
    rates of transmission occurring in the first and
    second months post-partum

Wiktor SZ, et al. XIIIth IAC, Durban, 2000.
Abstract 354
87
HIV/AIDS
  • In 2005, 38.6 million people worldwide were
    living with HIV, of which 24.7 million
    (two-thirds) lived in SSA
  • 4.1 million people worldwide became newly
    infected
  • 2.8 million people lost their lives to AIDS
  • New infections occur predominantly among the
    15-24 age group.
  • Previously unknown about 25 years ago. Has
    affected over 60 million people so far.

88
HIV Co-infections
  • Impact of TB on HIV
  • TB considerably shortens the survival of people
    with HIV/AIDS.
  • TB kills up to half of all AIDS patients
    worldwide.
  • TB bacteria accelerate the progress of AIDS
    infection in the patient
  • HIV and Malaria
  • Diseases of poverty
  • HIV infected adults are at risk of developing
    severe malaria
  • Acute malaria episodes temporarily increase HIV
    viral load
  • Adults with low CD4 count more susceptible to
    treatment failure

89
Global HIV Burden
90
Adults and Children With HIV/AIDS, 12/31/02
Eastern Europe Central \Asia 1,200,000
North America 980,000
Western Europe 570,000
East Asia Pacific 1,200,000
North Africa Middle East 550,000
Caribbean 440,000
South South-East Asia 6,000,000
Latin America 1,500,000
Sub Saharan Africa 29,400,000
Australia New Zealand 15,000
People living with HIV/AIDS
.......................... 42 million New HIV
infections in 2002 ..........................
. 5 million Deaths due to HIV/AIDS in 2002
.................... 3.1 million
91
HIV/AIDS
  • Interventions depend on
  • Epidemiology mode of transmission, age group
  • Stage of epidemic concentrated vs. generalized
  • Elements of an effective intervention
  • Strong political support and enabling
    environment.
  • Linking prevention to care and access to care and
    treatment
  • Integrate it into poverty reduction and address
    gender inequality
  • Effective monitoring and evaluation
  • Strengthening the health system and Multisectoral
    approaches
  • Challenges in prevention and scaling up treatment
    globally include
  • Constraints to access to care and treatment
  • Stigma and discrimination
  • Inadequate prevention measures.
  • Co-infections (TB, Malaria)?

92
  • Malaria

93
Malaria
  • Every year, 500 million people become severely
    ill with malaria
  • causes 30 of Low birth weight in newborns
    globally.
  • gt1 million people die of malaria every year. One
    child dies from it every 30 seconds
  • 40 of the worlds population is at risk of
    malaria. Most cases and deaths occur in SSA.
  • Malaria is the 9th leading cause of death in LICs
    and MICs
  • 11 of childhood deaths worldwide attributable to
    malaria
  • SSA children account for 82 of malaria deaths
    worldwide

94
Annual Reported Malaria Cases by Country (WHO
2003)?
95
Global malaria prevalence
96
Malaria Control
  • Malaria control
  • Early diagnosis and prompt treatment to cure
    patients and reduce parasite reservoir
  • Vector control
  • Indoor residual spraying
  • Long lasting Insecticide treated bed nets
  • Intermittent preventive treatment of pregnant
    women
  • Challenges in malaria control
  • Widespread resistance to conventional
    anti-malaria drugs
  • Malaria and HIV
  • Health Systems Constraints
  • Access to services
  • Coverage of prevention interventions

97
  • Hepatitis

98
Hepatitis and Liver Disease
  • 500-1000 therapeutic agents implicated in
    hepatitis
  • 15-20 million Americans are alcoholics
  • Tenth leading cause of death in USA
  • 25,000 deaths/year
  • 1 of all deaths
  • 40 of chronic liver disease HCV-related
  • 8-10,000 deaths/year.
  • HCV associated end stage liver disease is the
    most frequent
    indication for liver transplant
  • As HCV population ages incidence of chronic
    liver disease could
    increase substantially

99
  • Hepatitis
  • Asymptomatic - anicteric
  • Mild symptomatic - anicteric
  • Classic icteric infection (pertaining to or
    affected with jaundice)?
  • Fulminant hepatitis (sudden, flaring up type)?
  • Chronic hepatitis

100
Viral Hepatitis - Overview


Type of Hepatitis
A
B
C
D
E
Source of
feces
blood/ blood-derived/body fluids
feces
virus
Route of
Percutaneous/permucosal
fecal-oral
fecal-oral
transmission
Chronic
no
yes
yes
yes
no
infection
ensure safe
Prevention
pre/post-
pre/post-
blood donor
pre/post-
drinking
exposure
exposure
screening
exposure
immunization
immunization
risk behavior
immunization
water
modification
risk behavior
modification
101
Viral Hepatitis
102
Human Herpesviruses
  • Alpha Herpesviruses
  • Herpes Simplex Virus Type 1 (HSV-1)?
  • Herpes Simplex Virus Type 2 (HSV-2)?
  • Varicella Zoster Virus (HZV)?
  • Beta Herpesviruses
  • Cytomegalovirus (CMV)?
  • Human Herpesvirus Type 6 (HHV-6)?
  • Human Herpesvirus Type 7 (HHV-7)?
  • Gamma Herpesviruses
  • Epstein-barr Virus (EBV)?
  • Human Herpesvirus Type 8 (HHV-8)

  • Kaposis Sarcoma Asso. Herpesvirus

The Herpes Simplex Virus type 1 (HSV1), which is
the cause of cold sores, has an icosahedral
capsid shown here at 13 Å resolution.
103
Viruses - Herpes HSV-1 2
  • HSV-1
  • Oral/genital/mucocutaneous lesions

  • Acute gingivostomatitis
  • Pharyngitis

  • Herpes labialis

  • Keratoconjunctivitis
  • Encephalitis
  • Herpetic Whitlow

  • HSV-2
  • Oral/genital/mucocutaneous lesions
  • At least 14 persons gt 12 y.o. infected

  • 70-90 asymptomatic shedding
  • Only about 20 of HSV-2 Ab know they are
    infected

104
Herpes Viruses
  • EBV

  • Infects gt 85 of population

  • Agent of infectious mononucleosis
  • Cause of oral hairy leukoplakia


  • Oncogenic Burkitts Lymphoma
  • Linked to Hodgkins Disease/ other malignancies
  • CMV

  • Problematic in immumocomp. pts Retinitis,
    enteritis
  • Linked to vasculopathies, CAD?

  • Role in organ transplant rejection

  • Other graft/host involvement

Epstein-Barr virus (EBV) occurs world-wide and
infects most people at some point in their lives.
Children are largely immune to its effects, but
infection in older people can cause a condition
called infectious mononucleosis. Long-term
infection is, in very rare cases, linked to the
development of some forms of cancer.
105
Varicella-Zoster (VZV)?
  • Chickenpox Ubiquitous infection of childhood
  • Primary infection results in the characteristic
    disseminated cutaneous lesions.
  • The virus then establishes lifelong latency in
    dorsal root ganglia from whence it may reactivate
    to cause localized cutaneous eruptions known as
    herpes zoster or shingles.
  • Herpes zoster usually occurs later in life as a
    consequence of immunosuppressive illness or
    immunosuppressive medical therapy.
  • Declining VZV-specific immunity later in life is
    associated with an increased risk of herpes
    zoster.

106
Human Papillomavirus
  • Most common viral STD
  • Infects about 1/3 of sexually active
    population in USA
  • gt60 strains have been identified
  • 25 strains associated with genital
    tract
    infections/cancer
  • Strongly associated with
  • Cervical cancer
  • Causative agent
  • Oral cancer
  • Peri-anal/testicular cancer
  • Especially severe in HIV infected

107
Papilloma Focal Epithelial Hyperplasia (FEH)?
  • Etiological agent
  • Human papilloma virus (HPV)?
  • Wart
  • Clinical appearance
  • Flat (FEH)?
  • Siky
  • Cauliflower-like

108
  • Avian Influenza

109
Avian Influenza
  • Seasonal influenza causes severe illness in 3-5
    million people and 250000 500000 deaths yearly
  • 1st H5N1 avian influenza case in Hong Kong in
    1997.
  • By October 2007 331 human cases, 202 deaths.

110
Avian Influenza
  • Control depends on the phase of the epidemic
  • Pre-Pandemic Phase
  • Reduce opportunity for human infection
  • Strengthen early warning system
  • Emergence of Pandemic virus
  • Contain and/or delay the spread at source
  • Pandemic Declared
  • Reduce mortality, morbidity and social disruption
  • Conduct research to guide response measures
  • Antiviral medications Oseltamivir, Amantadine
  • Vaccine still experimental under development.
  • Can only be produced in significant quantity
    after an outbreak

111
Confirmed human cases Avian Influenza
112
Migratory pathway for birds and Avian influenza
113
The Spread of Avian Flu -- Status as of the
Summer 2008
114
  • West Nile Virus

115
WNV In USA
12/11/02
116
  • Spread by mosquitoes, which transmit it from
    infected birds. Mosquito species does make some
    difference.
  • -Alligators have WNV titers as high as birds,
    thus they can serve as a reservoir too.
  • -Certain titers need to be reached in order to
    infect mosquitoes. Horses and humans do not
    have high titers.
  • -300 captive alligators that died in 2002 in
    Florida, necropsies showed the alligators had
    high viral loads of WNV.

117
West Nile Virus Clinical Presentation
  • Incubation period 3 - 14 days
  • 20 develop West Nile fever
  • 1 in 150 develop meningoencephalitis
  • Advanced age primary risk factor for
    severe neurological disease
    and death
  • Mild dengue-like illness of sudden onset
  • Duration 3 - 6 days
  • Fever, lymphadenopathy, headache,
    abdominal pain, vomiting, rash,
    conjunctivitis, eye pain,
    anorexia
  • Symptoms of West Nile fever in contemporary
    outbreaks not fully studied

118
  • Suspect WNV when
  • Symptoms consistent with WNV
  • Unexplained bird or horse deaths
  • Mosquito season
  • Age gt 50 years
  • Symptoms
  • Most cases asymptomatic or mild dengue-like
    illness
  • Incubation period usually 5 (3) to 15 days
  • Fever, lymphadenopathy, headache
  • Abdominal pain, vomiting, rash, conjunctivitis
  • Muscle weakness and /or flaccid paralysis,
    hyporeflexia
  • EMG/NCV showing axonal neuropathy
  • Lymphocytopenia
  • MRI
  • Shows enhancement of leptomeninges and/or
    periventricular area
  • CNS involvement and death in minority of cases

119
West Nile Virus Human Cases in the US
1999 -62 cases with 7 deaths in New York
only 1999 -21 cases with 2 deaths in 12
states 2000 -66 cases with 9 deaths in 10
states 2001 -4156 cases with 284 deaths in 40
states 2002 -9862 cases with 264 deaths in 46
states 2004 -2539 cases with 100 deaths in 42
states 2005 -3000 cases with 119 deaths in 44
states 2006 -4269 cases with 177 deaths in 44
states 2007 -3630 cases with 124 deaths in 43
states
120
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121
U.S. cases of West Nile for 2002
122
U.S. cases of West Nile for 2004
123
U.S. cases of West Nile for 2005
124
U.S. cases of West Nile for 2007
125
  • African Trypanosomiasis

126
African Trypanosomiasis
  • Called Sleeping Sickness, vector is the tsetse
    fly
  • Classical example of an emerging infection,
    1890-1930
  • Leading public health problem in Africa during
    that time, colonialism brou
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