Emerging and Re-emerging Infectious Diseases

Samantha Rosenthal, MPH, PhD Candidate

WNV

Monkeypox from Prairie Dogs

Are infectious diseases emerging more than before?

Institute of Medicine 1992 Report on Emerging Infections

Defined emerging infections as: “New, reemerging or drug-resistant infections whose incidence in humans has increased within the past two decades or whose incidence threatens to increase in the near future.”

Major Factors Contributing to Emerging Infections: 1992

1. Human demographics and behavior

2. Technology and Industry

3. Economic development and land use

4. International travel and commerce

5. Microbial adaptation and change

6. Breakdown of public health measures

Institute of Medicine Report, 1992

More Factors Contributing to Emerging Infections: 2003

7. Human vulnerability

8. Climate and weather

9. Changing ecosystems

10.Poverty and social inequality

11.War and famine

12.Lack of political will

13. Intent to harm

Institute of Medicine Report, 2003

Emerging Infections:Human Demographics, Behavior, Vulnerability

• More populations with weakened immune system: elderly, HIV/AIDS, cancer patients and survivors, persons taking antibiotics and other drugs

•More people, more crowding•Changing sexual mores (HIV, STDs)•Injection drug use (HIV, Hepatitis C)•Changing eating habits (foodborne infections)

Emerging Infections:Technology and Industry

• Mass food production (Campylobacter, E.coli

O157:H7, etc…)• Use of antibiotics in

food animals (antibiotic-resistant bacteria)

•New drugs for humans (prolonging vulnerability)

Emerging Infections:Economic Development, Land Use, Changing

Ecosystems

• Changing ecology influencing waterborne, vectorborne transmission (e.g. dams, deforestation)

•Contamination of watershed areas by cattle (Cryptosporidium)•More exposure to wild animals and vectors (Lyme disease)

Emerging Infections:International Travel and Commerce

• Persons infected with an exotic disease anywhere in the world can be into major US city within hours (SARS, VHF,…)

• Foods from other countries imported routinely into US (Cyclospora,….)

• Vectors hitchhiking on imported products (Asian tiger mosquitoes on lucky bamboos,….)

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Speed of Global Travel in Relation toWorld Population Growth

From: Murphy and Nathanson. Semin. Virol. 5, 87, 1994CDC

Emerging Infections:Microbial Adaptation and Change

• Increased antibiotic resistance with increased use of antibiotics in humans and food animals (VRE, VRSA, penicillin- and macrolide-resistant Strep pneumonia, multidrug-resistant Salmonella, TB,….)

• Jumping species from animals to humans (avian influenza, HIV, SARS?)

Emerging Infections:Poverty, Social Inequality, Breakdown of Public

Health Measures

• Lack of basic hygienic infrastructure (safe water, foods)• Inadequate vaccinations (measles, diphtheria)

• Discontinued mosquito control efforts (dengue, malaria)• Lack of monitoring and reporting (SARS

Emerging Infections:Intent to Harm

• Bioterrorism: Anthrax in US 2001

• Bio-Crimes: Salmonella in OR, Shigella in TX.

• Potential agents: Smallpox, Botulism toxin, Plague, Tularemia, ….

CDC

Prevention of Emerging Infectious Diseases Will Require Action in

Each of These Areas

Surveillance and Response

Applied Research

Infrastructure and Training

Prevention and ControlCDC

Enhance communication: locally, regionally,

nationally, globally

Increase global collaboration

Share technical expertise and resources

Provide training and infrastructure support globally

Ensure political support

Ensure judicious use of antibiotics

Vaccines for all

Preventing EmergingInfectious Diseases: More to Do

Rosenthal SR, Ostfeld RS, McGarvey ST, Lurie MN, and Smith KF. The Overlooked Pathways to Infectious Disease Emergence. Emerging Infectious Diseases; under review.

Rosenthal SR, Ostfeld RS, McGarvey ST, Lurie MN, and Smith KF. The Overlooked Pathways to Infectious Disease Emergence. Emerging Infectious Diseases; under review.

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Questions?

Preventing EmergingInfectious Diseases

Surveillance and Response

Detect, investigate, and monitor emerging

pathogens, the diseases they cause, and

the factors influencing their emergence,

and respond to problems as they are

identified.

CDC

Applied Research

Integrate laboratory science and

epidemiology to increase the

effectiveness of public health

practice.

Preventing EmergingInfectious Diseases

CDC

Infrastructure and Training

Strengthen public health infrastructures to support surveillance, response, and research and to implement prevention and control programs.

Provide the public health work force with the knowledge and tools it needs.

Preventing EmergingInfectious Diseases

CDC

Prevention and Control

Ensure prompt implementation of

prevention strategies and enhance

communication of public health

information about emerging diseases.

Preventing EmergingInfectious Diseases

CDC