NEW EMERGING AND
REEMERGING DISEASES •
Definitions
•New Emerging infectious diseases
newly identified or
previously unknown infections
•Re-emerging infectious diseases
re-appearance of, or increase in number of,
infections from a disease previously known
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New Emerging Infectious Diseases:
Definition
Diseases of infectious origin
whose incidence in humans has increased
within the recent past or threatens to increase
in the near future,
including:
previously unknown infectious diseases;
known but appearing in new geographic
areas;
or increase abruptly;
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Infectious Diseases: A World in Transition
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•The human species
Continues
to change and to change its surroundings:
the ways we live, work, relax; the places we go;
the foods we eat ...
•The changing nature of our interactions
with each other and with our environment alters
the dynamics of disease epidemiology
and exposes us to new threats.
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ENVIRONTMENT
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EMERGING DISEASES ARE NOT NEW TO MANKIND
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NEWLY IDENTIFIED PHATOGENS
(1973- 1989)
1973 Rotavirus
1975 Parvovirus B19
1976 Cryptosporidium parvum
1977 Ebola virus, Legionella pneumophilia,
Hantaan virus, Campylobacter jejuni
1980 HTLV-1
1981 Staphylococcus toxin
1982 E. coli O157, HTLV-2, Borrelia burgdoferi
1983 HIV virus, Helicobacter pylori
1988 HHV-6, Hepatitis E
1989 Ehrlichia chaffeensis, Hepatitis C
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Newly identified pathogens (1990 - 1999)
1990 Guanarito virus
1991 Encephalitozzon hellem
1992 Vibrio cholerae O139
1992 Bartonella henselae
1993 Sabia virus
1995 Hepatitis G virus
1995 Human herpesvirus-8
1996 TSE causing agent (nvCJD)
1997 Avian influenza (Type A H5N1)
1999 Nipah virus, Avian Influenza H9N1, Stealth viruses
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Newly identified pathogens (1997 – 2009)
•1998 Nipah encephalitis
•2003 SARS
•2004 Avian influenza H5N1
•2006 Chikungunya- re-emergence
•2009 Pandemic influenza A H1N1
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Since 1973
39 newly identified pathogens,
examples :
1973 Rotavirus
1977 Ebola virus, Hantaan virus
1980 HTLV-1
1983 HIV virus H pylori
1988 Hepatitis E
1992 Vibrio cholerae O139
1996 Avian influenza A (H5N1)
1999 Nipah virus
2003 SARS
Others re-emerged
Dengue/DHF
Cholera Malaria
Chikungunya
J. Encephalitis
Leptospirosis
N.meningitidis
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Current estimates1,415 microbes
are infectious for human.
Of these, 868 (61%)
considered zoonotic.
70% of newly recognized pathogens
are zoonoses.
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Current estimates1,415 microbes are infectious for human.
Of these, 868 (61%) considered zoonotic.
70% of newly recognized pathogens are zoonoses.
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Risk factors for emerging zoonoses:
close human animal interface in Asia
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Examples of recent emerging and re-emerging diseases
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Emergence of HPAI (H5N1)
2003-June 2008 a total of 385 cases with 243 deaths
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GEOGRAPHIC DISTRIBUTION OF PROBABLE CASES
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SARS:
THE FIRST EMERGING INFECTIOUS DISEASE OF THE 21ST CENTURY
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EMERGENCY DENGUE FEVER/DENGUE HAEMORRHAGIC FEVER
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