S. Machado

The Global Threat of Epidemic Emergent-Re-Emergent Infectious Diseases: Lessons Learned

and Prospects for the Future

Duane J Gubler Professor

Signature Research Program in Emerging Infectious Diseases Duke-NUS Graduate Medical School, Singapore

Duke Global Health Inst, 3 Sept, 2013

The Global Threat of Epidemic Emergent/ Re-Emergent Infectious Diseases

• Background• Case studies of selected epidemic IDs• Reasons for emergence• Lessons learned• Prospects for the future • How do we reverse the trend?

The Global Threat of Infectious Diseases

Emerging and re-emerging diseases

Adapted from Morens, Folkers, Fauci 2004 Nature 430; 242-9

Emerging diseasesRe-emerging diseases

Chikungunya

Dengue

Dengue

A/H1N1

A/H1N1H7N9

MERS

MERS

The Global Threat of Emerging Zoonotic Diseases

• Natural Hosts Rodents Bats Birds Others

• Modes of Transmission Direct contact Respiratory Vector-borne Usually silent

• Type of Pathogen Viruses Bacteria Parasites

Major Infectious Disease Epidemics since 1980• Dengue/DHF-1970s, SE Asia, global

• HIV/AIDS-1980s-Africa,global

• Drug resistant TB-1990s, US, global

• Cholera-1991-Americas

• Plague-1994-India, global

• Foot & Mouth disease-1995,2000- Taiwan & UK

• West Nile-1990s-Mediterranean, Americas

• BSE-1990s- UK, Canada, US

• Swine fever, 1996- Netherlands

• Avian influenza-1997- HK-global

• Nipah encephalitis-1998-Malaysia,Asia

• SARS-2002- Asia, global

• Chikungunya-2004-Africa, Asia

• H1N1 influenza-2009-Mexico?,global

• Hand, foot and mouth disease, Asia

• MERS and H7N9 ?

Public health impact Social impact

Economic impact

Dengue Hemorrhagic FeverDengue Hemorrhagic Fever

The changing epidemiology of dengueThe changing epidemiology of dengue

Source: DengueNetSource: DengueNet

No

of

Cas

esN

o o

f C

ases

Expanding geographic distribution

Increased epidemic activity

Hyperendemicity

Emergence of DHF

West Nile Virus in the Western HemisphereWest Nile Virus in the Western Hemisphere

0

2000

4000

6000

8000

10000

12000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

total cases reported to CDC WNND cases reported

Epidemic West Nile Virus in the United States

4 States

62 Cases

1999

12 States

21 Cases

2000

27 States

66 Cases

2001

44 States

4156 Cases

2002

46 States

9862 Cases

2003

2004

47 States

2535 Cases

2005

48 States

2819 Cases

2006

48 States

4219 Cases

Persistent Epidemic Transmission FociHave Developed

Epidemic/Epizootic West Nile Virus

1937

1950-75

1994 - 1999 Adapted from Gubler, 2007

1937

1950-93

1994 - 2007

Epidemic/Epizootic West Nile Virus

Egypt 1951France 1965

South AfricaIsrael 1952

Romania 1996 MKenya 1998Senegal 1993Morocco 1996Italy 1998Volgograd 1999New York 1999Israel 1998NY2000 3282NY2000 3356NY 1999 equineNY 1999 humConn 1999MD 2000NJ 2000Israel 1999 HC.Afr.Rep 1989

Senegal 1979Algeria 1968

C.Afr.Rep 1967Iv.Coast 1981

Kunjin 1960Kunjin 1973Kunjin 1984bKunjin 1991Kunjin 1984aKunjin 1966Kunjin 1994

India 1955aIndia 1980India 1958India 1955bKenyaUgandaSenegal 1990Uganda 1937

C.Afr.Rep 1972aC.Afr.Rep 1983

Uganda 1959C.Afr.Rep 1972b

Madagascar 1988Madagascar 1986Madagascar 1978JE SA 14

India

Kunjin

US/Israel

Phylogenetic Tree of West Nile Viruses

LIN-1

LIN-22

1

Molecular Evolution of WN Virus Strains

Plague Pandemics

• Justinian’s Plague (mid-6th Century A.D.)• Black Death (mid-14th Century A.D.)• Modern Pandemic (1894 – mid-1900s)

Global Distribution of Plague

Countries reporting plague, 1970-2000

Probable Sylvatic foci

Compiled from WHO, CDC, and country sources

Surat

Potential Spread of Pnuemonic Plague out of India, 1994

India

Delhi

Calcutta

MadrasBombay

Pneumonic Plague in India

• Indian outbreak was a complete surprise – no plague confirmed in India since 1966

• Clinical and lab diagnosis were confused

• Media and panic driven epidemic

• First epidemic to impact globalization

• Caused huge economic loss for India (> $3 billion)