Emerging and re-emerging Disease
“Emerging and Re-emerging
humans disease
Abdul Aziz Djamal
Dept of Microbiology Andalas University
Newly identifed and previously unknown
infectious agent that cause public health
problem locally or globally
Re-emerging Infectious
Disease
Infectious disease that have been known for
sometime and had fallen to such a low level
and no longer consider as a public health
problem and now showing upward trend in
prevalence or incidence globally
Examples of Emerging and Re-Emerging
Infectious Disease: past 10 years A Fauci,
NIAID/NIH, 2005
Major and minor killers: global impact viewed
on a ‘Richter’ (logarithmic) scale
7
Tobacco
Infant/child ARI & diarrhoeal dis
Malaria
Road accidents
Non-HIV tuberculosis
HIV
Viruses
HBV + HCV
6
Measles
RSV, Rota virus
Influenza
Dengue
5
H Papilloma v
Hospital infection
Suicide
4
10,000-fold
difference in
impact
West Nile virus
SARS
Ebola
Polio
Hanta virus
3
2
1
Log
vCJD
10
Weiss & McMichael, 2004
Outline of Talk
Microbes, infectious diseases: recent trends
Infectious diseases as result of major changes in
human ecology and environmental – historical
transitions; current conditions
Examples of infectious disease risks
Travel, trade
Land use, agriculture
Intensive animal husbandry
Climate variability, climate change
Needed: a more ecological perspective
Receding – then Resurging?
1950s-60s: Infectious diseases apparently receding
in developed countries
Antibiotics and vaccines
Pesticides to control mosquitoes
Improved surveillance and control measures – internationally
coordinated
Early 1970s: Authorities proclaimed end of
infectious disease era. Premature!
>30 new or newly-discovered human IDs over past 30 yrs
We overlooked the ecological/evolutionary dimensions
Avian ’flu, H5N1
Mad Cow Disease (BSE) vCJD
Nipah viral encephalitis, Malaysia (1997-99)
Choi Young-Soo/Associated Press Yonhap
South Korean health workers disinfecting a chicken farm north of Seoul last week. Though 140 million birds have died or been killed as a preventive measure in Asia, the risks of wide human
infection are not known.
Previous ’flu epidemics (1918-19, ’57, ’68)
South Korean health workers disinfecting a chicken farm in April, 2005.
Though several hundred million birds have died or been killed as a
preventive measure in Asia, the human epidemic risk remains unknown.
Human-Microbe Transitions over
the Millennia
Pre-historic: hunter-gatherers disperse into distant new
environments
1. Local agrarianism/herding: 5-10,000 yrs ago
E
L
2. Trans-continental: 1,000-3,000 yrs ago
A
C
S
3. Inter-continental: From c. 1500 AD
n
i
s
e
s
4. Today, global: Fourth historical
eatransition
v
i
s
s
e
c
c
u
S
r
c
n
ei
Factors in Emerging/Re-emerging
Infectious Diseases
• Microbial adaptation and change
• Human susceptibility to infection
ageing, HIV, IV drugs, transplantation, transfusion
• Population growth and density
• Urbanization, crowding – social and sexual relations
• Globalization of travel and trade
• Live animal markets
• Intensified livestock production
• Misuse of antibiotics (humans & domestic animals)
• Changes to ecosystems (deforestation, biodiversity loss)
• Global climate change
Zoonotic Sources: Land-use,
Livestock, Wild-life
Clearing forests for agriculture
Viral haemorrhagic fevers in South America: peasant-farmers
Guanarito, Sabia, Kunjin, etc.
Eating infected animals
New variant Creutzfeldt Jacob disease (from BSE)
Cultivation of infected animals
Nipah viral encephalitis (pig farms in Malaysia)
West Nile virus (goose “fois gras” farms in Ramala, Israel)
Collection and trade of wild game
HIV (bush meat: primates)
Ebola (bush meat?)
SARS (civet cat?)
Incidence of BSE in UK, 1987-99 (c.180K cases)
1988/9 bans: Sale of nervous tissue and offal for human consumption
Eating cattle >30 months old
Mammalian products in ruminant feed
BUT: no ban on feed for swine or poultry
Human vCJD (end 2003) -- 125 cases: UK-117, France-6, Ireland-1, Italy-1
Nipah Viral Encephalitis, in Malaysia
01/97
Farm worker hospitalized with viral encephalitis (VE).
10/97
First death (pig-farm worker) from VE.
02/98
3 farm workers develop VE.
11/98
Health Minister declares it ‘Japanese Encephalitis’ mosquito
control and vaccine program. But outbreak spreads.
1-2/99 Pig farmers begin ‘fire sales’ of pigs. Outbreak recedes a little.
02/99
Laboratories receive first samples of infected human
tissue. “New” virus? Mass pig culling begins. Villagers flee.
03/99 Virus isolated and identified with reagents used to characterize
Hendra virus (a recently-identified horse virus, from Queensland).
04/99
‘Nipah virus’ discovery announced. Culling continues.
05/99
WHO declares outbreak over (265 cases, 40% fatal).
02/00
Last death. Fruit bats (flying foxes) deemed the likely reservoir.
Travel and Trade: examples
Aedes albopictus mosquito eggs in
shipments of used tyres dengue fever
Long-distance travel; wild animal trade
HIV/AIDS
West Nile Virus (New York City, 1999)
SARS, 2003
SARS
Severe
Acute
Respiratory
Syndrome
A genetic model for the Coronavirus family.
(Photo: J Oxford, Retroscreen Virology Ltd)
Key wildlife trade routes in SE Asia and China
China
Lao PDR
Vietnam
Cambodia
Environmental Changes
Land use, forest clearance
Biodiversity losses, extinctions
Dams, irrigation
Climate change
Log-transformed A. darlingi abun
An. 1.5
Darlingi abundance
(log scale)
No. of survey
sites = 2433
1.2
.9
.6
.3
0
1
2
3
Secondary
(deforested) (deforested) growth
Village
Farm
4
Forest
Patz et al, 2003
Lyme Disease: Influences of Habitat
Fragmentation & Biodiversity Loss
High Lyme
Disease risk
Woodland suburban
housing (NE USA)
High tick density
and high tick infection
prevalence infected deer
Complex life- Expanding mouse
populations
cycle of tick
Less diversity of vertebrate
predators and viral hosts
Forest fragmentation,
hunting (wolves,
passenger pigeons)
Many competent
reservoir species
less dilution by
incompetent reservoir
species
Poor inter-species
regulation
Adapted from: R. Ostfeld
Climate Change and Infectious Disease
Some recent changes in ID patterns may reflect the
influence of climate change (debate continues)
Tick-borne encephalitis (north spread in Sweden)
Cholera in Bangladesh (strengthening relationship with El
Niño events)
Malaria ascent in east African highlands
Time-trends in incidence of (reported) food poisoning, esp.
Salmonellosis
Dengue Fever: Estimated geographic region suitable
for maintenance of Ae. aegypti, under alternative
climate scenarios for 2050
.
.
Darwin
Katherine
.
Darwin
.
Katherine
.
Broome
.
Port Headland
.
..
.
Townsville
.
.
.
Rockhampton
.
Mackay
.
Rockhampton
.
.
Darwin
Brisbane
Katherine
.
Broome
.
Port Headland
.
Carnarvon
NCEPH/CSIRO/BoM/UnivOtago, 2003
.
Risk region under medium
emissions scenario, 2050
Carnarvon
Mackay
Current risk region for
dengue
Townsville
Port Headland
Cairns
.
.
Cairns
Broome
.
.
Cairns
Townsville
.
Mackay
.
Rockhampton
Risk region under high
emissions scenario, 2050
MALARIA IN ZIMBABWE, UNDER CLIMATE CHANGE
Source: Kris Ebi
Source: Kris Ebi
Source: Kris Ebi
Summary
Humans, domestic animals and wildlife are inextricably
linked by epidemiology of infectious diseases (IDs).
IDs will continue to emerge, re-emerge and spread.
Human-induced environmental changes, inter-species
contacts, altered social conditions, demography and
medical technology affect microbes’ opportunities.
Also:
New research, technology and collaborative networks
will also elucidate role of infection in diverse, mostly
chronic, diseases of unknown cause . . . .
INFECTIOUS CAUSES OF
CHRONIC DISEASE: Examples
Disease
Cause
Cervical cancer
Chronic hepatitis, liver cancer
Lyme disease (arthritis)
Whipple’s disease
Bladder cancer
Stomach cancer
Peptic ulcer disease
Human papilloma virus
Hepatitis B and C viruses
Borrelia burgdorferi
Tropheryma whippelii
Schistosoma haematobium
Helicobacter pylori
Helicobacter pylori
Atherosclerosis (CHD)
Diabetes mellitus, type 1
Multiple sclerosis
Inflammatory bowel disease
Chlamydiae pneumoniae
Enteroviruses (esp. Coxsackie)
Epstein-Barr v, herpes vv?
Mycobacterium avium sub-spp.
Paratuberculosis, Yersinia
Conclusion I: Understanding what
promotes human-microbe contacts
(i)
Intensified modification/exploitation of natural
environments and food production.
(ii) Disturbance of natural ecosystems and their
various internal biotic controls.
(iii) Poverty, crowding, social disorder, mobility and
political instability.
Conclusion II:
Microbes as Co-Habitants
Microbes’ interest is in survival and
reproduction. They have no malign
intent; morally neutral!
Their evolution-based drive to survive is
as strong as ours (and draws on much
longer experience).
That’s all,
folks
Air trajectories @ 100 m altitude
27 Dec 1997: Tropical Cyclone Sid
Backwards trajectory analysis of JE
humans disease
Abdul Aziz Djamal
Dept of Microbiology Andalas University
Newly identifed and previously unknown
infectious agent that cause public health
problem locally or globally
Re-emerging Infectious
Disease
Infectious disease that have been known for
sometime and had fallen to such a low level
and no longer consider as a public health
problem and now showing upward trend in
prevalence or incidence globally
Examples of Emerging and Re-Emerging
Infectious Disease: past 10 years A Fauci,
NIAID/NIH, 2005
Major and minor killers: global impact viewed
on a ‘Richter’ (logarithmic) scale
7
Tobacco
Infant/child ARI & diarrhoeal dis
Malaria
Road accidents
Non-HIV tuberculosis
HIV
Viruses
HBV + HCV
6
Measles
RSV, Rota virus
Influenza
Dengue
5
H Papilloma v
Hospital infection
Suicide
4
10,000-fold
difference in
impact
West Nile virus
SARS
Ebola
Polio
Hanta virus
3
2
1
Log
vCJD
10
Weiss & McMichael, 2004
Outline of Talk
Microbes, infectious diseases: recent trends
Infectious diseases as result of major changes in
human ecology and environmental – historical
transitions; current conditions
Examples of infectious disease risks
Travel, trade
Land use, agriculture
Intensive animal husbandry
Climate variability, climate change
Needed: a more ecological perspective
Receding – then Resurging?
1950s-60s: Infectious diseases apparently receding
in developed countries
Antibiotics and vaccines
Pesticides to control mosquitoes
Improved surveillance and control measures – internationally
coordinated
Early 1970s: Authorities proclaimed end of
infectious disease era. Premature!
>30 new or newly-discovered human IDs over past 30 yrs
We overlooked the ecological/evolutionary dimensions
Avian ’flu, H5N1
Mad Cow Disease (BSE) vCJD
Nipah viral encephalitis, Malaysia (1997-99)
Choi Young-Soo/Associated Press Yonhap
South Korean health workers disinfecting a chicken farm north of Seoul last week. Though 140 million birds have died or been killed as a preventive measure in Asia, the risks of wide human
infection are not known.
Previous ’flu epidemics (1918-19, ’57, ’68)
South Korean health workers disinfecting a chicken farm in April, 2005.
Though several hundred million birds have died or been killed as a
preventive measure in Asia, the human epidemic risk remains unknown.
Human-Microbe Transitions over
the Millennia
Pre-historic: hunter-gatherers disperse into distant new
environments
1. Local agrarianism/herding: 5-10,000 yrs ago
E
L
2. Trans-continental: 1,000-3,000 yrs ago
A
C
S
3. Inter-continental: From c. 1500 AD
n
i
s
e
s
4. Today, global: Fourth historical
eatransition
v
i
s
s
e
c
c
u
S
r
c
n
ei
Factors in Emerging/Re-emerging
Infectious Diseases
• Microbial adaptation and change
• Human susceptibility to infection
ageing, HIV, IV drugs, transplantation, transfusion
• Population growth and density
• Urbanization, crowding – social and sexual relations
• Globalization of travel and trade
• Live animal markets
• Intensified livestock production
• Misuse of antibiotics (humans & domestic animals)
• Changes to ecosystems (deforestation, biodiversity loss)
• Global climate change
Zoonotic Sources: Land-use,
Livestock, Wild-life
Clearing forests for agriculture
Viral haemorrhagic fevers in South America: peasant-farmers
Guanarito, Sabia, Kunjin, etc.
Eating infected animals
New variant Creutzfeldt Jacob disease (from BSE)
Cultivation of infected animals
Nipah viral encephalitis (pig farms in Malaysia)
West Nile virus (goose “fois gras” farms in Ramala, Israel)
Collection and trade of wild game
HIV (bush meat: primates)
Ebola (bush meat?)
SARS (civet cat?)
Incidence of BSE in UK, 1987-99 (c.180K cases)
1988/9 bans: Sale of nervous tissue and offal for human consumption
Eating cattle >30 months old
Mammalian products in ruminant feed
BUT: no ban on feed for swine or poultry
Human vCJD (end 2003) -- 125 cases: UK-117, France-6, Ireland-1, Italy-1
Nipah Viral Encephalitis, in Malaysia
01/97
Farm worker hospitalized with viral encephalitis (VE).
10/97
First death (pig-farm worker) from VE.
02/98
3 farm workers develop VE.
11/98
Health Minister declares it ‘Japanese Encephalitis’ mosquito
control and vaccine program. But outbreak spreads.
1-2/99 Pig farmers begin ‘fire sales’ of pigs. Outbreak recedes a little.
02/99
Laboratories receive first samples of infected human
tissue. “New” virus? Mass pig culling begins. Villagers flee.
03/99 Virus isolated and identified with reagents used to characterize
Hendra virus (a recently-identified horse virus, from Queensland).
04/99
‘Nipah virus’ discovery announced. Culling continues.
05/99
WHO declares outbreak over (265 cases, 40% fatal).
02/00
Last death. Fruit bats (flying foxes) deemed the likely reservoir.
Travel and Trade: examples
Aedes albopictus mosquito eggs in
shipments of used tyres dengue fever
Long-distance travel; wild animal trade
HIV/AIDS
West Nile Virus (New York City, 1999)
SARS, 2003
SARS
Severe
Acute
Respiratory
Syndrome
A genetic model for the Coronavirus family.
(Photo: J Oxford, Retroscreen Virology Ltd)
Key wildlife trade routes in SE Asia and China
China
Lao PDR
Vietnam
Cambodia
Environmental Changes
Land use, forest clearance
Biodiversity losses, extinctions
Dams, irrigation
Climate change
Log-transformed A. darlingi abun
An. 1.5
Darlingi abundance
(log scale)
No. of survey
sites = 2433
1.2
.9
.6
.3
0
1
2
3
Secondary
(deforested) (deforested) growth
Village
Farm
4
Forest
Patz et al, 2003
Lyme Disease: Influences of Habitat
Fragmentation & Biodiversity Loss
High Lyme
Disease risk
Woodland suburban
housing (NE USA)
High tick density
and high tick infection
prevalence infected deer
Complex life- Expanding mouse
populations
cycle of tick
Less diversity of vertebrate
predators and viral hosts
Forest fragmentation,
hunting (wolves,
passenger pigeons)
Many competent
reservoir species
less dilution by
incompetent reservoir
species
Poor inter-species
regulation
Adapted from: R. Ostfeld
Climate Change and Infectious Disease
Some recent changes in ID patterns may reflect the
influence of climate change (debate continues)
Tick-borne encephalitis (north spread in Sweden)
Cholera in Bangladesh (strengthening relationship with El
Niño events)
Malaria ascent in east African highlands
Time-trends in incidence of (reported) food poisoning, esp.
Salmonellosis
Dengue Fever: Estimated geographic region suitable
for maintenance of Ae. aegypti, under alternative
climate scenarios for 2050
.
.
Darwin
Katherine
.
Darwin
.
Katherine
.
Broome
.
Port Headland
.
..
.
Townsville
.
.
.
Rockhampton
.
Mackay
.
Rockhampton
.
.
Darwin
Brisbane
Katherine
.
Broome
.
Port Headland
.
Carnarvon
NCEPH/CSIRO/BoM/UnivOtago, 2003
.
Risk region under medium
emissions scenario, 2050
Carnarvon
Mackay
Current risk region for
dengue
Townsville
Port Headland
Cairns
.
.
Cairns
Broome
.
.
Cairns
Townsville
.
Mackay
.
Rockhampton
Risk region under high
emissions scenario, 2050
MALARIA IN ZIMBABWE, UNDER CLIMATE CHANGE
Source: Kris Ebi
Source: Kris Ebi
Source: Kris Ebi
Summary
Humans, domestic animals and wildlife are inextricably
linked by epidemiology of infectious diseases (IDs).
IDs will continue to emerge, re-emerge and spread.
Human-induced environmental changes, inter-species
contacts, altered social conditions, demography and
medical technology affect microbes’ opportunities.
Also:
New research, technology and collaborative networks
will also elucidate role of infection in diverse, mostly
chronic, diseases of unknown cause . . . .
INFECTIOUS CAUSES OF
CHRONIC DISEASE: Examples
Disease
Cause
Cervical cancer
Chronic hepatitis, liver cancer
Lyme disease (arthritis)
Whipple’s disease
Bladder cancer
Stomach cancer
Peptic ulcer disease
Human papilloma virus
Hepatitis B and C viruses
Borrelia burgdorferi
Tropheryma whippelii
Schistosoma haematobium
Helicobacter pylori
Helicobacter pylori
Atherosclerosis (CHD)
Diabetes mellitus, type 1
Multiple sclerosis
Inflammatory bowel disease
Chlamydiae pneumoniae
Enteroviruses (esp. Coxsackie)
Epstein-Barr v, herpes vv?
Mycobacterium avium sub-spp.
Paratuberculosis, Yersinia
Conclusion I: Understanding what
promotes human-microbe contacts
(i)
Intensified modification/exploitation of natural
environments and food production.
(ii) Disturbance of natural ecosystems and their
various internal biotic controls.
(iii) Poverty, crowding, social disorder, mobility and
political instability.
Conclusion II:
Microbes as Co-Habitants
Microbes’ interest is in survival and
reproduction. They have no malign
intent; morally neutral!
Their evolution-based drive to survive is
as strong as ours (and draws on much
longer experience).
That’s all,
folks
Air trajectories @ 100 m altitude
27 Dec 1997: Tropical Cyclone Sid
Backwards trajectory analysis of JE