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EmergingDiseases3802019TODAY.pptx

EMERGING INFECTIOUS DISEASES:

Introduction

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Age-Specific Mortality and Proportion of All Deaths Due to 9

Infectious Diseases

Source: JAMA 1999;281:61-66

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“During the postwar era American enjoyed unchallenged hegemony and unprecedented affluence….the economy hummed so smoothly that the nation had enough left over to fund a massive war on poverty…..” --Bruce J. Schulman, The Seventies --

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Background

Optimism about infectious diseases

Vaccinations decreased rates of many diseases

Measles

Mumps

Polio

Others

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Optimism

Antibiotics

Strep and rheumatic fever

Bacterial pneumonia

Many others

Elimination of one feared disease: smallpox

Combination of:

Vaccination

Prudent strategies

International cooperation

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Optimism Led to…..

Surgeon General Declares in 1967 that

Infectious diseases have been conquered

Attention needs to be devoted mostly to chronic diseases and diseases of lifestyle

Beginning of erosion of public health system—designed for infectious diseases

Decrease in funding in infectious disease training and research

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Consequences

Public health surveillance ill-prepared for any new threats

Only most senior clinicians and public health officials had adequate training in infectious disease

Government structure ill-prepared

Public thought that serious infections thing of past

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Lurking in the Background….

Infections have always been part of human experience

Evolved system of co-existence between microbes and humans

Growing international ties could introduce new pathogens through…….

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Triangle of Human Ecology (of Disease)

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The Early 1990’s

HIV/AIDS had been thought of as isolated problem but…

Hantavirus in Four Corners;

Cryptosporidiosis in Milwaukee;

E. coli 0157:H7 in Washington and Oregon

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“A Fragile Equilibrium”

“A careful review of infectious disease trends shows a fragile equilibrium between humans and infectious microorganisms.”

--David Satcher, Surgeon General, EID, 1995

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MAJOR NEW

JOURNAL 1995

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“EMERGING INFECTIOUS DISEASES: WHAT ARE THEY?

New infections resulting from changes or evolution of existing organisms

Known infections spreading to new geographic areas or populations

Previously unrecognized infections appearing in areas undergoing ecologic transformation

Old infections reemerging as a result of antimicrobial resistance in known agents or breakdowns in public health measures.

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1ST MAJOR REPORT

ON EMERGING

INFECTIONS

INSTITUTE OF

MEDICINE

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“It is this committee’s considered opinion that that the next major infectious agent to emerge as a threat to health in the United States, may, like HIV, be a pathogen that has not been previously recognized—” Institute of Medicine, 1992

In Fact…

HIV/AIDS not an isolated problem;

Public health community began waking up to

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Causes of Emergence

Changing demographics

Changing travel patterns—commerce

Host (human) behavior

Technological change

Ecological and climate change

Microbial change

Breakdown in a buffer—public health

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INSTITUTE

OF MEDICINE

REPORT

2003

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Source: Emerging Inf Dis, April 2016 (cdc.gov/eid)

Drivers of Threat, EID April 2016

Factors of Emergence in IOM-2

Microbial adaptation and change

Human susceptibility to infection

Climate and weather

Changing ecosystems

Economic development and land use

Intent to harm

Technology and industry

International travel and commerce

Breakdown of public health

War and famine

Lack of political will

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“SARS: A Very

21st Century Disease”

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Selected Emerging Infectious Diseases

Souce: NIAID of NIH

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Temporal Distn EIDs

Source: Jones et al, Nature, Feb 2008

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Relative Risk of EID Event

Source: Jones et al., Nature, Feb 2008.

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Changing Behavior

Demography and population geography—

Where people are

Behavior:

What people do, how they live and act

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Injectable Drug Use (IDU)

Nobody really knows why it happens

Related to:

Poverty

Affluence

Peer pressure

Psychological factors

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Property of IDU

It is addictive physically;

It is habituating psychologically;

It gets to be a major “need”

It is a commodity;

People will seek to minimize cost—

NEEDLE SHARING

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Diseases Associated With IDU

Hepatitis C--bloodborne

up to 3 million Americans

Over 10,000 deaths/yr

Only solution: liver transplants

Hepatitis B—bloodborne, sexual, vertical

Other forms of hepatitis

HIV/AIDS

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HIV/AIDS and Drug Use

Up to 35% of those entering drug treatment programs are HIV positive;

What about those who do not seek treatment?

25% of new cases of HIV/AIDS in US due to IDU

50% of women w/HIV due to IDU

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Technology and Industry

Food processing

E. coli 0157:H7

Listeriosis

Botulism

BSE (mad cow disease) and vCJD

Others

Air transportation

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Technology and Industry

Food processing

E. coli 0157:H7

Listeriosis

Botulism

BSE (mad cow disease) and vCJD

Others

Air transportation

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HIV/AIDS

Emergence from African rainforest;

Species transfer;

Diffusion through truck drivers;

Intercontinental diffusion

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Travel and Pathogens

Americans traveling abroad

Foreigners coming to US through:

Immigration

Travel

Cargo could serve as “vector” of pathogens

Airplanes

Ships

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Movement of Goods

Containerization and movement of goods;

Increasing role of foreign trade in the economy;

Specific data are in the book

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Container ship

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Examples of Disease Spread Due to Commodity Shipment

Aedes albopictus to Houston;

Ebola among monkeys, Virginia

“Airport malaria”

Imports of food

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“Perhaps the greatest problem associated with international commerce and its relation to disease emergence is the lack of appropriate, widely available diagnostic tests to allow effective screening of animals and products made in animals) that are destined for investigational use”—Institute of Medicine

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Thus there….

Is a tremendous need for social scientific involvement

Disease ecology is a blend of social science, ecology, and microbiology

If the problem is fundamentally social, it must be treated in social terms

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Long History of Travel and Disease

Introduction of the “Black Plague” into Europe from Asia;

The “Columbian” Exchange—

Introduction of smallpox to the Americas;

Possible introduction of syphilis in Europe;

Numerous influenza pandemics

Smallpox

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The roles of travel and commerce are not new, but the speed at which it is a major force is much greater

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Types of Travel

International

Has received most attention—interest in globalization and “permeable” borders;

Domestic—

Has received less attention in context of emerging diseases

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International Travel

>500 million international travelers/year;

>110 million intercontinental travelers;

>500,000 international flights/year

Actual data are difficult to derive

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Institute of Medicine Predictions

Lassa Fever may be introduced to US, other countries;

Malaria and other vector-borne diseases may be reintroduced

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Changing Demographics

Tremendous population growth

Urbanization;

Suburban growth (peripheral growth)

Growth at edge of city

Intersection with ecological change—

Contact of population with new biogeographical areas

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Urbanization

Concentration of more people into denser settlements;

Cities as “microbe magnets” –Laurie Garrett The Coming Plague

Factors promoting emergence in cities—

Density

Behavior

Poverty

Recent migration

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Planning

No integration of urban planning with health care needs;

No cooperation between sectors such as:

Urban sprawl;

Economic development;

Mosquito abatement;

Sewers and water….and

HEALTH CARE!

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Challenges

Understand what underlies emerging diseases;

Develop public health structure—

Training

Surveillance and detection

Disease control

Flexibility of understanding and response

Difference between public health and clinical medicine

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Optimism Led to…..

Surgeon General Declares in 1960’s that

Infectious diseases have been conquered

Attention needs to be devoted mostly to chronic diseases and diseases of lifestyle

Beginning of erosion of public health system—designed for infectious diseases

Decrease in funding in infectious disease training and research

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Consequences

Public health surveillance ill-prepared for any new threats

Only most senior clinicians and public health officials had adequate training in infectious disease

Government structure ill-prepared

Public thought that serious infections thing of past

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Lurking in the Background….

Infections have always been part of human experience

Evolved system of co-existence between microbes and humans

Growing international ties could introduce new pathogens through…….

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General Factors in Transmission

Ecological setting

Behavior

Host characteristics

Population characteristics

Movement

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Factors of Emergence in IOM-2

Microbial adaptation and change

Human susceptibility to infection

Climate and weather

Changing ecosystems

Economic development and land use

Intent to harm

Technology and industry

International travel and commerce

Breakdown of public health

War and famine

Lack of political will

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Factors of Emergence in IOM-2

Microbial adaptation and change

Human susceptibility to infection

Climate and weather

Changing ecosystems

Economic development and land use

Intent to harm

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Technology and industry

International travel and commerce

Breakdown of public health

War and famine

Lack of political will

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Emerging Diseases

New diseases;

Newly discovered diseases;

Re-emerging diseases;

Diseases that are spreading to new regions;

Diseases that are increasing in intensity

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