Emerging & Re-emerging
Infectious Diseases
Dr. Garba Iliyasu
MBBS,FMCP(Infectious Diseases)
Outline Of Presentation
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Infectious diseases- trends
Definition of emerging & re-emerging diseases
Factors contributing to emergence
Examples
Public health response
Infectious Disease- Trends
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Receded in Western countries 20th century
Urban sanitation, improved housing, personal
hygiene, antisepsis & vaccination
Antibiotics further suppressed morbidity &
mortality
The leading cause of morbidity and mortality
in developing countries
Infectious Disease- Trends
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Since last quarter of 20th century- New &
Resurgent infectious diseases
Definition
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Emerging infectious disease
Newly identified & previously unknown
infectious agents that cause public health
problems either locally or internationally
Definition
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Re-emerging infectious disease
Infectious agents that have been known for some
time, had fallen to such low levels that they were
no longer considered public health problems &
are now showing upward trends in incidence or
prevalence worldwide
Emerging Infections in the
World since 1973
1973
1976
1977
1977
1977
1977
1980
1981
1982
1982
1982
Rotavirus
Cryptosporidium
Ebola virus
Legionella
Hantaan virus
Campylobacter
HTLV-1
Toxin prod. S.aureus
E.coli 0157:H7
HTLV-II
Borrelia burgdorferi
Enteritis/Diarrhea
Enteritis/Diarrhea
VHF
Legionnaire’s dz
VHF w/ renal flr
Enteritis/Diarrhea
Lymphoma
Toxic Shock Synd.
HUS
Leukemia
Lyme disease
Emerging Infections in the
World and US since 1973
1983
1983
1988
1988
1989
1989
1990
1991
1992
1992
HIV
Helicobacter pylori
Hepatitis E
HHV 6
Hepatitis C
Ehrlichia chaffeensis
Guanarito virus
Encephalitozoon
Vibrio cholerae O139
Bartonella henselae
AIDS
Peptic ulcer dz
Hepatitis
Exanthema subitum
Hepatitis
Human ehrlichiosis
VHF
Disseminated dz
Cholera
Cat scratch dz
Emerging Infections in the
World and US since 1973
1993
1994
1994
1995
1995
1996
1997
1999
1999
2001
2003
2003
2007
Sin Nombre virus
Sabia virus
Hendra virus
Hepatitis G
H Herpesvirus-8
vCJD prion
Avian influenza (H5N1)
Nipah virus
West Nile virus
BT Bacillus anthracis
Monkeypox
SARS-CoV
New strains of Ebola
Hanta Pulm. Synd.
VHF
Respiratory dz
Hepatitis
Kaposi sarcoma
Variant CJD
Influenza
Encephalitis
Encephalitis
Anthrax
Pox
SARS
VHF
Examples of Re-Emerging
Infectious Diseases
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Diphtheria- Early 1990s epidemic in Eastern
Europe(1980- 1% cases; 1994- 90% cases)
Cholera- 100% increase worldwide in 1998
(new strain eltor, 0139)
Human Plague- India (1994) after 15-30
years absence. Dengue/ DHF- Over past 40
years, 20-fold increase to nearly 0.5 million
(between 1990-98)
GLOBAL EXAMPLES OF EMERGING AND
RE-EMERGING INFECTIOUS DISEASES
AS Fauci
After great advances in medical research
and antimicrobial drug discovery,
technology development, improvement
in sanitation..
WHY are microbes still posing such a
problem?
Emergence of infectious disease are the
results from dynamic interactions
between rapidly evolving infectious
agents and changes in the
environment and in host behaviour
that provide such agents with
favourable new ecological niches
Factors Contributing To
Emergence
AGENT
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Evolution of pathogenic infectious agents
(microbial adaptation & change)
Development of resistance to drugs
Resistance of vectors to pesticides
Factors Contributing To
Emergence
HOST
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Human demographic change (inhabiting new
areas)
Human behaviour (sexual & drug use)
Human susceptibility to infection
(Immunosuppression)
Poverty & social inequality
Factors Contributing To
Emergence
ENVIRONMENT
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Climate & changing ecosystems
Economic development & Land use
(urbanization, deforestation)
Technology & industry (food processing &
handling)
CONTD.
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International travel & commerce
Breakdown of public health measure
(war, unrest, overcrowding)
Deterioration in surveillance systems
(lack of political will)
INTERNATIONAL
TRAVEL
International travel and Commerce.
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365 days to circumnavigate the
globe…now it takes 36 hours
-used to quarantine ships, but 36 h faster
than disease incubation
International travel
-Travel and HIV/AIDS.
-Silk route and plague.
-Slaves trade and yellow fever.
-Migration to new world and smallpox.
-Cholera and Hajj.
Transmission of Infectious Agent
from
Animals to Humans
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>2/3rd emerging infections originate from
animals- wild & domestic
Emerging Influenza infections in Humans
associated with Geese, Chickens & Pigs
Animal displacement in search of food after
deforestation/ climate change (Lassa fever)
Humans themselves penetrate/ modify
unpopulated regions- come closer to animal
reservoirs/ vectors (Yellow fever, Malaria)
Emerging Zoonoses: Humananimal interface
Avian influenza virus
Borrelia burgdorferi: Lyme
Bats: Nipah virus
Deer tick (Ixodes
scapularis)
Ebola virus
Marburg virus
Hantavirus Pulmonary Syndrome
Mostomys rodent: Lassa fever
Emerging Infectious Diseases of
the 21st century
1. SARS
No infectious disease has spread so fast and far as SARS did in 2003
SARS Cases
19 February to 5 July 2003
Total: 8,439 cases, 812 deaths,
30 countries in 7-8 months
Europe:
10 countries (38)
Canada (243)
Russian Fed. (1)
Mongolia (9)
China (5326)
USA (72)
Kuwait (1)
India (3)
Colombia (1)
Hong Kong (1755)
Korea Rep. (3)
Macao (1)
Taiwan (698)
Malaysia (5)
Viet Nam (63)
Singapore (206)
Brazil (3)
Indonesia (2)
Philippines (14)
Thailand (9)
South Africa (1)
(
Australia (5)
New Zealand (1)
Source: www.who.int.csr/sars
SARS
Mid November 2002
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Guangdong Province, China
“ outbreak of atypical pneumonia”
11 February 2003
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WHO informed
305 cases (5 deaths)
30% in health care workers
July 2003
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8,437 probable cases from 32 countries
major foci in China, SE Asia and Toronto
SARS CoV - infectivity
(MMWR 2003:52 (18): 405-11)
ANIMAL ORIGIN OF SARS-CoV?
- IgG seroprevalence: animal traders (13.0%); HCW (2.9%);
Guangdong CDC workers (1.6%); Healthy adults (1.3%)
- RR (95%CI) for IgG by animal trade:
masked palm civet 7.9 (5.0 – 12.6)
wild boar 6.2 (3.8 – 10.3)
muntjac deer 6.1 (3.4 – 10.9)
hare 5.0 (2.5 – 10.2)
Others- cat, fowl, pheasant, snakes (not significant)
- Martina B et al 2003 demonstrated ease of infection &
transmssion in and between cats and ferrets
- Guan Y et al 2003 isolated SARS-CoV from Himalayan civet cat,
raccoons, and animal traders in southern China…all the animal
strains retain the 29 nucleotides missing in human isolates
2003
Guan Y et al 2003; Martina B et al 2003; MMWR
2. Influenza A
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Was known as endemic gastrointestinal
viruses of wild waterfowl, now has jump
species into domestic fowl, farm
animals and humans
Antigenic changes in haemagglutinin
and neurominidase glycoproteins –
‘shifts’ (major antigenic changes in HA
or NA)
Deadly pandemics has occurred in
1888, 1918, 1957 and 1968
Dr. KANUPRIYA CHATURVEDI
FIGURE 6. Documented human infections with avian
influenza viruses, 1997–2004.
Highly Pathogenic Avian Influenza
(H5N1)
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In 2003, avian influenza H5N1 in birds
affected 60 countries across Asia, Europe,
Middle-East & Africa
>220 million birds killed by AI virus or culled
to prevent further spread
Majority of human H5N1 infection due to
direct contact with birds infected with virus
Novel Swine (H1N1)-2009
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Swine flu causes respiratory disease in pigs –
high level of illness, low death rates
Occasional human swine infection reported
Swine Flu
Influenza A (H1N1)
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March 18 2009 – outbreak reported in
Mexico
April 15th CDC identifies H1N1 (swine flu)
April 25th WHO declares public health
emergency
April 27th Pandemic alert raised to phase 4
April 29th Pandemic alert raised to phase 5
Influenza A (H1N1)
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By May 5th more than 1000 cases confirmed in 21
countries
Worldwide-
162,380 cases
1154 deaths
Screening at airports for flu like symptoms
(especially passengers coming from affected area
3. MERS Cov
Middle east respiratory corona virus
Novel virus
Identified in 2013 in Saudi Arabia
Links to camels
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Dr. KANUPRIYA CHATURVEDI
3. Lassa fever
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12 Jan 1969- 1st recognized case an American missionary nurse in
Lassa, NE- Nigeria
25 Jan 1969- Air lifted to Evangel. Hospital Jos, N. Nigeria
26 Jan 1969- Pt was cared by two american nurses but died that day
One of the two caring nurses fell sick after an 8d IP and died after an
illness lasting 11d
20 Feb 1969- Head Nurse of the hospital where autopsy for 1st case
was done fell sick
Pt evacuated to USA by air on a commercial Boeing 707, separated
with curtain only
Pt recovered after severe protracted illness at ICU of Columbia
University NY
Lassa fever
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A virus was isolated and later named Lassa at Yale Arbovirus Research
(YAR) Unit
9 Jun 1969- One of YAR virologists fell ill and survived only as a result
of an immune plasma transfusion donated by the surviving third case
30 Nov 1969- A Laboratory technician at YAR fell ill and died
Jan-Feb 1970- a devastating hospital outbreak at Vom and Jos:
Outbreak affected 28 patients with 12 deaths, including the American
doctor who first identified the disease and did autopsies
Epidemiology
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Endemic in areas of West Africa, including Nigeria,
Liberia, Sierra Leone, and Guinea
Estimated 300,000-500,000 infections/year, with
5000 deaths
Rodent-to-human transmission (the “multimammate
rat”, Mastomys species-complex)
Secondary human-to-human transmission with the
potential for nosocomial outbreaks with high casefatality
Transmission
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Rodent-to-human:
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Inhalation of aerosolized virus
Ingestion of food or materials
contaminated by infected rodent
excreta
Catching and preparing Mastomys as a
food source
Transmission
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Human-to-human:
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Direct contact with blood, tissues,
secretions or excretions of infected
humans
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Needle stick or cut
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Inhalation of aerosolized virus
4. Ebola virus infection
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1976- First Major
Outbreak
1976- Sudan & Zaire
Occur concurrently
Ebola Zaire & Sudan
Ebola History
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1989 and 1992: Ebola Reston
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USA and Italy
Imported macaques from Philippines
1994: Ebola Côte d'Ivoire
Center for Food Security and
Public Health Iowa State
University - 2004
Ebola Response Update for 16 July 2014
Distribution of EVD Outbreaks
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Majority of
outbreaks are due
to Ebola virus
(species Zaire ebolavirus)
7
745
4
5
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16 July 2014
Ebola Response Update for 16 July 2014
Current West African outbreak -as of 8th Sept 2014
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Guinea
Sierra Leone
Liberia
Nigeria
Senegal
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EBOLA ZAIRE
Total –
 4293
Mortality
 2296 including
8 in Nigeria
PCF=53%
http://www.cdc.gov/vhf/ebola/outbreaks/guinea/index.html
45
21 July 2014
Overview cont.
Arenavirida
Bunyaviridae Filovirida
e
e
Flaviviridae
Junin
CrimeanCongo H.F.
Ebola
Kyasanur
Forest
Disease
Machupo
Hantavirus
Marburg
Omsk H.F.
Sabia
Rift Valley fever
Guanarito
Lassa
Yellow Fever
Dengue
Ebola out break link to
primates
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The link between human infection by the
Ebola virus and their proximity to primates is
clear.
-Outbreaks occurred in countries with large
population of wild gorilla and chimpanzee.
- The outbreaks coincided with the outbreaks
in wild animals.
- The same distinct viral strains were isolated
in animal carcasses and in the bodies of those
who handled those carcasses.
- These outbreaks were preceded by an
abnormally large death in wild Gorilla
populations.
Where does Ebola hide?
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2002- Fruit Bats
Antibodies against
Ebola (Pourrut et al. 2005)
Ebola Gene sequences
in liver and spleen
(Leroy et al. 2005)
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Fruit bats do not show
any symptoms
Best candidate to be
the reservoir
Ebola Response Update for 16 July 2014
Ebola virus ecology
49
16 July 2014
Transmission.
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Person to person transmission occurs by
direct contact with infected body fluids such as
blood, sweat, saliva, semen, vaginal fluids,
urine, sputum
 direct inoculation by contaminated instruments
such as needles, pins, razor blades
Care givers in the home
Funeral practices
Health care workers
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Virology
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Pleomorphic negative-sense RNA virus
Viral genome is 19kb long encoding:
(1)Structural protiens-
glycoprotien(GP), nuclear protien (NP),
matrix protien(VP24 & VP40)
(2) Non structural protiens-VP30 &
VP35
(3)Viral polymerase
Pathogenesis
Glycoprotiens(GP) plays a major role in
pathogenesis
-Attaches the virus to epithelial cells, cells lining
the blood vessel, hepatocytes, neutrophils,
monocytes
- Inhibit early steps of neutrophil activation
 Release of cytokines associated with
inflammation, fever, damage to the vascular
integrity, viral cytopathic effect on cells
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Clinical Presentation
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Incubation period: 2-21days
Phase A: Influenza like symptoms- fever, body weakness,
head ache, arthralgia, myalgia, sore throat, nausea,
vomitting
Phase B: Persistent fever, head ache, intense fatigue,
diarrhea, abdominal pain, anorexia, vomitting (1-6)
Phase C: Pseudo-remission, some may recover (7-8)
Phase D: Aggravation with sudden deterioration,
respiratory distress, bleeding, neuro-psychiatric
manifestation, petaechiae rashes, cardiovascular collapse.
Mortality almost 100% (Ndambi et al., 1999)
Diagnosis.
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Diagnosis is by
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ELISA for specific IgG antibody (presence
of IgM antibody indicates recent infection);
ELISA antigen detection in blood, serum or
organ homogenates
PCR
Postmortem diagnosis is through
immunohistochemical examination of
formalin –fixed skin biopsy specimens
Treatment
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No approved treatment or vaccine for
Ebola
Treatment is primarily supportive
Fluid and electrolytes management
Control of bleeding
Oxygen therapy
Pain management
Antibiotics for secondary bacterial
Experimental therapy
Drugs:
 Zmapp
 Favipiravir
 Estrogen receptor drugs e.g clomiphene
 Amiodarone
 TKM-Ebola
Vaccines: DNA vaccines, Adenovirus-based
vaccine, VSIV vaccine
5. MDR TB estimated cases
Africa low HIV
incidence, 10,449
Established Market
Economies, 1,681
Central Europe,
1,462
Latin America,
11,301
Eastern
Mediterranean
Region, 18,330
Africa high HIV
incidence, 48,141
Eastern Europe,
65,853
Western Pacific
Region, 152,018
Global burden:
424,203 cases
South-east Asia,
114,967
Zignol M. et al. J Infect Dis. 2006;194:479-85.
Total number of MDR-TB cases estimated to have
occurred in Africa in 2004 is 58,590
(95% CLs: 48,835-118,089)
RESISTANCE IN NIGERIA
Fawcett et al (1976) [naïve]
INH res 7%
SM res 2%
Kolo (1991)
INH res 19%
SM res 13%
PZA res 29%
Idigbe et al 92 (1992) [treated]
Overall res 56%
INH res 38%
Rif res 2%
≤ 500
501-999
1000-4999
Abdullahi (2006)
INH res 29%
SM res 14%
PZA res 24%
≥ 5000
Lawson et al (2007) unpublished [naïve]
MDR TB 12.5%
The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization
concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent
approximate border lines for which there may not yet be full agreement.  WHO 2006. All rights reserved
XDR-TB
Extensively drug-resistant TB (XDR TB) defined as:
MDR TB with further resistance to at least three of the six
major classes of second line drugs
Source: MMWR March 24, 2006 / Vol 55 / No. 11, 301-305
Resistance to:
• At least rifampicin and isoniazid (MDR-TB)
• A fluoroquinolone
• One or more of the following injectable drugs:
kanamycin, amikacin, capreomycin
Source: Global XDR-TB Task Force, 7-8 October, 2006
Is malaria an “emerging” disease?
YES !!!
[At least drug-resistant malaria is an emerging disaster]
Bioterrorism
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Possible deliberate release of infectious
agents by dissident individuals or terrorist
groups
Biological agents are attractive instruments
of terror- easy to produce, mass casualties,
difficult to detect, widespread panic & civil
disruption
CONTD.
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Highest potential- B. anthracis, C.
botulinum toxin, F. tularensis, Y. pestis,
Variola virus, Viral haemorrhagic fever
viruses
Likeliest route- aerosol dissemination
Key Tasks in Dealing with Emerging
Diseases
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Surveillance at national, regional, global level
 epidemiological,
 laboratory
 ecological
 anthropological
Investigation and early control measures
Implement prevention measures
 behavioural, political, environmental
Monitoring, evaluation
Key tasks - carried out by whom?
Global
Regional
Synergy
National
Dr. KANUPRIYA CHATURVEDI
What skills are needed?
Infectious
diseases
Epidemiology
Public
Health
Telecom. &
Informatics
International
field
experience
Laboratory
Information
management
Multiple expertise needed !
Lesson learnt
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An infectious disease in one country is a
threat to all
Important role of air travel in
international spread
Tremendous negative economic impact
on trade, travel and tourism, estimated
loss of $ 30 to $150 billion during SIRS
THANKS FOR LISTENING