Why Have we Seen Such a Dramatic Increase in Epidemic Infectious

Diseases?

• Complacency, Lack of Political Will

• Policy Changes

• Changes in Public Health

• Changing Life Styles/Behavior

• Microbial Adaptation

• Technology

• Intent to Harm

• Climate Change?

Dengue f

ever

outbreak kills

dozens

in Bra

zil

Deadly by the Dozen: 12

Diseases Climate Change

May Worsen

Another death in

Tonga from

dengue fever

Paraguay: Dengue and yellow

fever outbreak DREF

Operation No. MDRPY003

Update No.1

Dengue fever warning for Thailand

An exotic blend

Dengue Fever is ready to

spread across the country

Health alert -

Dengue fever risk

Dengue fears

Climate change will fuel

dengue - WHO exec

Climate change to hit coastal

pregnancies

Warming Increases Malaria, Dengue Fever Threat,SOUTH AMERICA: Climate Change

Fuels Spread of Dengue Fever

         

Scientists Predict Global Warming Will Lead to Spread of Disease

As Earth Warms Up, Tropical Virus Moves to Italy“ nytimes.com/2007/12/23

Chikungunya disease in NYC? Warming could make it happen Virus causes severe joint pain, is spread by two mosquito species; NBC News

Asian mosquito 'could bring

tropical diseases to Britain‘, The

Independent, 2013

Climate change, globalization, and otherdrivers have made Europe a “hot spot” foremerging infectious diseases, which callsfor changes in monitoring systems27 APRIL 2012 VOL 336 SCIENCE.

“Fueled by climate change, dengue fever is on the rise again throughout the developing world,

particularly in Latin America”.

Reference: Dengue fever: a deadly scourge. The Economist, April 19, 2007.

Dengue/Dengue Hemorrhagic Fever, Average Annual Number of Cases Reported to WHO, 1955-2003

0100000200000300000400000500000600000700000800000900000

1000000

1955

-195

9

1960

-196

9

1970

-197

9

1980

-198

9

1990

-199

9

2000

-200

3

Num

ber

of C

ases

There is no solid scientific evidence to date that global warming has been a major driving force of the 20th century re-emergence of vector-borne infectious diseases!

Why Have we Seen Such a Dramatic Increase in Epidemic Infectious

Diseases?

• Demographic Changes (Pop Growth) Environmental Change

- Uncontrolled Urbanization

- Agricultural/Land Use Practices

- Deforestation

- Climate change

Animal Husbandry

• Modern Transportation (Globalization) Increased Movement of People, Animals,

Commodities

• Lack of Public Health Infrastructure

Major Drivers

Global population- 1950-2050Global population- 1950-2050

Evaluation of urban and rural population between 1950 and 2050Evaluation of urban and rural population between 1950 and 2050

Pop

ulat

ion

(Mill

ions

)P

opul

atio

n (M

illio

ns)

Urban Growth in Asian(1) and American(2) Cities, 1950-2010

1. Mean population of Dhaka, Bangkok, Jakarta, Manila and Saigon.

2. Mean population of Rio de Janeiro, Sao Paulo, San Juan, Caracas and Guayaquil.

The global air networkThe global air network

Average annual number of global airline passengers by decade, 1950-2010

IATA 2010IATA 2010

Mill

ion

of P

ass

enge

r (M

il)M

illio

n o

f Pa

ssen

ger

(Mil)

DecadeDecade

Commercial Air Traffic Over a 24 Hour Period

Global distribution of dengue virus serotypes, 1970Global distribution of dengue virus serotypes, 1970

Gubler, 1998

Global distribution of dengue virus serotypes, 2013Global distribution of dengue virus serotypes, 2013

Adapted from Gubler, 1998

Exotic Infectious Diseases That HaveRecently Been Introduced to the US

• West Nile Fever• Dengue Fever• Yellow Fever• Mayaro Fever• Chikungunya• Epidemic Polyarthritis• SARS• Influenza• Lassa Fever

• Monkeypox• CJD/BSE• HIV/AIDS• Cholera• E. coli O157• Malaria• Leishmaniasis• Chagas Disease• Cyclospora

Live Animal Importation into the USA - 2002

• 47,000 mammals 28 species of rodents

• 379,000 birds

• 2 million reptiles& Poisonous snakes

• 49 million amphibians

• 223 million fish

Data from U.S. Fish & Wildlife Service

Exotic Mosquito Species Recently Introduced and Established in the US

• Aedes (Stegomyia) albopictus

• Ochlerotatus (Aedes Finlaya) togoi

• Ochlerotatus (Aedes Finlaya) japonicus

• Aedes bahamensis

• Culex biscayensis

Urbanization Agricultural, land use and animal husbandry

changes/practices

Habitat alteration

Species’ Ecological-evolutionary DynamicsOpportunistic habitat expansion/ecological release

Vector (domestication) Domestic vector/reservoir species Wildlife/reservoir transport/encroachment Human encroachment

Host-Pathogen DynamicsEmergence Processes of ‘Host-Parasite Biology’

Host switching (host novelty) • Breaching of pathogen persistence thresholdsTransmission amplification and genetic change (pathogen novelty)

Disease Emergenceecosystem continuum

HUMAN

ECOSYSTEM

NATURAL

ECOSYSTEM

Global climate change

Demographic ChangesTechnology/Globalization

Socio-cultural organization

REGIONAL ENVIRONMENTAL CHANGE

New York City

Aedes aegyptiAedes aegypti

POTENTIAL GLOBAL SPREAD OF URBAN YELLOW FEVER

Global Threat of Epidemic Infectious Diseases

• Disease and Trade-interwoven History 14th century, Europe discovers exotic goods from

Asia

• Global Trade Flourishes 18th, 19, 20th centuries

• New Millennium Integrated global economic system with a

transnational flow of knowledge, capital, products, people, animals, and pathogens

Rapid spread of epidemic infectious disease from point of origin

Global Threat of Epidemic Infectious Diseases

• Dawn of 21st century, we have come full circle

• Expect the unexpected

• New diseases will emerge

• Old diseases will re-emerge

• Modern transportation and globalization will disseminate

• Unlikely that a zoonotic disease can be eradicated

Lessons Learned

Global Threat of Epidemic Infectious Diseases

Lessons Learned

• Disease detection and identification systems must be improved and maintained

• International communication and cooperation are critical

• Rapid response plans must be developed and implemented appropriately

• More emphasis must be placed on prevention as opposed to emergency response

• Outbreaks should be contained as local public health events if possible

• Public and Press need reliable information to prevent panic and overreaction

The Global Threat of Infectious Diseases

Global Trends, 2012-20025

• Most of global economic growth in Asian countries

Increased trade

Increased movement of people, animals and commodities from Asia to rest of world

• Most of global population growth in cities of Asia Rural to urban circular migration

• Globalization

• Increased movement of pathogens

Global Threat of Epidemic Infectious Diseases

Challenge to Reverse the Trend

• Movement of Pathogens and Vectors via Modern Transportation

• International cooperation and data sharing

• Lack of Effective Laboratory-based Surveillance

• Lack of Public Health Infrastructure to Prevent & control Vector-borne and Zoonotic Diseases

Trained personnel

Laboratory capacity

Tools (vaccines, drugs, insecticides, vector control tools)

Understanding disease ecology

• Political Will

Economic support

Regional prevention and control programs