The document discusses emerging and re-emerging infectious diseases, their causes, examples, and strategies for prevention and control. Emerging diseases are caused by new pathogens while re-emerging diseases were previously controlled but have risen again. Factors contributing to emergence include human behavior, travel, microbial adaptation, and breakdown of public health measures. Examples provided include SARS, H1N1 influenza, Ebola, Zika, and Nipah virus. Prevention strategies involve controlling reservoirs, interrupting transmission, protecting susceptible populations, strengthening surveillance, and encouraging research. Public health authorities and doctors play key roles in awareness,

1. Emerging & Re-emerging
infectious Diseases
1

2. 2
Introduction
 Emerging Infectious Diseases:
• Emerging infectious diseases are “New diseases; new problem (New
threats)”
• An emerging infectious disease is a one that is caused by a newly
discovered infectious agent
or
• by a newly identified pathogen, which has emerged and whose
incidence in humans has increased during the last 2 decades and is
threatening to increase in the near future.

3. 3
 Re-emerging Infectious Diseases:
• Re-emerging infectious diseases are “old diseases, new problem.
(New threats)”.
• A re-emerging infectious disease is a one which was previously
controlled but once again has risen to be a significant health problem.
• This term also refers to that disease which was formerly confined to
one geographic area, has now spread to other areas.

4. 4
Factors contributing to the emergence of infectious
diseases:
1. Human demographics and behaviour
2. Technology and industry
3. Economic development and land use
4. International travel and commerce
5. Microbial adaptation and change
6. Breakdown of public health measures
7. Human susceptibility to infection
8. Climate and weather
9. Changing ecosystems
10. Poverty and social inequality
11. War and famine
12. Lack of political will
13. Intent to harm

5. 5
Factors contributing to the emergence
 AGENT:
• Evolution of pathogenic infectious agents (microbial adaptation & change)
• Development of resistance to drugs: Wrong prescribing practices
Non-adherence by patients
Counterfeit drugs
Use of anti-infective drugs in animals & plants
• Resistance of vectors to pesticides

6. 6
HOST:
• Human demographic change (inhabiting new areas)
• Human behaviour: 1. Unsafe sexual practices (HIV, Gonorrhoea, Syphilis)
2. Changes in agricultural & food production patterns-
food- borne infectious agents (E. coli)
3. Increased international travel (Influenza)
• Human susceptibility to infection (Immunosuppression)
• Poverty & social inequality

7. 7
ENVIRONMENT:
• Climate & changing ecosystems:
Deforestation forces animals into closer human contact- increased possibility for
agents to breach species barrier between animals & humans
EL Nino- Triggers natural disasters & related outbreaks of infectious diseases
(Malaria, Cholera)
Global warming- spread of Malaria, Dengue, Leishmaniasis, Filariasis
• Economic development & Land use (urbanization, deforestation)
• Technology & industry (food processing & handling)
• International travel & commerce
• Deterioration in surveillance systems (lack of political will)

8. • Breakdown of public health measure (war, unrest, overcrowding):
Poor populations- major reservoir & source of continued transmission
Poverty- Malnutrition- Severe infectious disease cycle
Lack of funding, Poor prioritization of health funds, Misplaced in curative rather
than preventive infrastructure, failure to develop adequate health delivery systems
• Uncontrolled Urbanization & Population Displacement:
Growth of densely populated cities- substandard housing, unsafe water, poor
sanitation, overcrowding, indoor air pollution (>10% preventable ill health)
Problem of refugees & displaced persons
Diarrhoeal & Intestinal parasitic diseases,ARI 8

9. Examples:
Source: NATURE; Vol 430; www.nature.com/nature
9

10. 10
• 1993: Hantavirus pulmonary syndrome (United States)
• 1994: Plague (India)
• 1995: Ebola fever (Democratic Republic of Congo)
• 1996: New variant Creutzfeldt-Jakob disease (United Kingdom)
• 1997: H5N1 influenza (Hong Kong);
• 1998: Nipah virus encephalitis (Malaysia, Singapore)
• 1999: West Nile virus encephalitis (Russia, United States)
• 2000: Rift Valley fever (Kenya, SaudiArabia, Yemen); Ebola fever(Uganda)
• 2001:Anthrax (United States); foot-and-mouth disease(United Kingdom)
• 2002: Vancomycin-resistant Staphylococcus aureus (United States)
• 2003: Severe acute respiratory syndrome (SARS) (multiple countries); monkeypox (USA)
• 2004: H5N1 influenza (SoutheastAsia)
Examples of Emerging Infectious Diseases

11. 11
Examples of Emerging Infectious Diseases
• Hepatitis C- First identified in 1989
In mid 1990s estimated global prevalence 3%
• Hepatitis B- Identified several decades earlier
Upward trend in all countries
Prevalence >90% in high-risk population
• Zoonoses- 1,415 microbes are infectious for human
Of these, 868 (61%) considered zoonotic
70% of newly recognized pathogens are zoonoses
Emerging Influenza infections in Humans associated with Chickens, Pigs

12. Emerging Zoonoses: Human-animal interface
Marburg virus
Hantavirus Pulmonary Syndrome
Ebola virus
Borrelia burgdorferi
(Lyme disease)
Deer tick
(Ixodes scapularis)
Mostomys rodent: Lassa fever
Avian influenza virus Bats: Nipah virus
12

13. SARS Cases
19 February to 5 July 2003
China (5326)
Singapore (206)
Hong Kong (1755)
Viet Nam (63)
Europe:
10 countries (38)
Thailand (9)
Brazil (3)
Canada (243)
USA (72)
Colombia (1)
Kuwait (1)
South Africa (1)
India (3)
Australia (5)
New Zealand (1)
Korea Rep. (3)
Macao (1)
Taiwan (698)
Malaysia (5)
Indonesia (2)
Philippines (14)
Mongolia (9)
Russian Fed. (1)
Total: 8,439 cases, 812 deaths,
30 countries in 7-8 months
Source: www.who.int.csr/sars
SARS
The First Emerging Infectious Disease Of The 21st Century
No infectious disease has spread so fast and far as SARS did in 2003
13

14. 14
Lesson learnt from SARS
• 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
• High level commitment is crucial for rapid containment
• WHO can play a critical role in catalyzing international cooperation and support
• Global partnerships & rapid sharing of data/information enhances preparedness and
response

15. 15
Swine Flu (H1N1)
• Swine flu causes respiratory disease – high level of illness, low death rates
• Causative agent- InfluenzaA- RNAviruses of the family Orthomyxoviridae
• RNAvirus- highly mutagenic
• Pigs can get infected by human, avian and swine influenza virus
• Pandemic outbreak sinceApril 2009
• April 15th 2009 CDC identifies H1N1 (swine flu)
• April 25th 2009 WHO declares public health emergency
• By May 5th 2009 more than 1000 cases confirmed in 21 countries
• May 16th 2009India reports first confirmed case
• Cases of swine flu have been reported in India, with over 31,156 positive test
cases and 1,841 deaths up to March 2015

16. 16

17. 17

18. 18
Highly Pathogenic Avian Influenza (H5N1)
• Since Nov 2003, avian influenza H5N1 in birds affected 60 countries across Asia,
Europe, Middle-East &Africa
• >220 million birds killed by this virus or culled to prevent further spread
• Majority of human H5N1 infection due to direct contact with birds infected with
virus

19. 19

20. 1.Own your own way how can you
prevent the spread of diseases?
At least 200 words

21. 21
Emerging Food borne
&
water borne disease
• Accounts for 20 million cases in the world annually (T.D. Chugh-2008)
• Incidence is increasing
• Half of all known food borne pathogens discovered during the past 25 years
• Most common associated organisms are: Entero hemorrhagic Escherichia coli, Vibrio
cholerae, Campylobacter sp.

22. 22
Ebola
• Ebola was first discovered in 1976 near the Ebola River. Since then, outbreaks have
appeared sporadically inAfrica.
• Ebola Hemorrhagic Fever Outbreak:
• 2000-2001: Uganda
• 2002-2003: Gabon and Democratic Republic of the Congo (DRC)
• 2004: South Sudan
• 2007: DRC, Uganda.
• 2011-2012: Uganda, DRC
• 2014-2016: WestAfrica

23. 23
Zika
• Zika virus was first discovered in a monkey in the Zika Forest of Uganda in 1947.
• In 1952, the first human cases of Zika were detected and since then, outbreaks of Zika
have been reported in tropicalAfrica, SoutheastAsia, and the Pacific Islands.
• Before 2007, at least 14 human cases of Zika had been documented, although other
cases were likely to have occurred and were not reported.
• The first travel notice for Zika in Brazil was posted in June 2015.
• On January 22, 2016, CDC activated its Emergency Operations Center (EOC) to
respond to outbreaks of Zika occurring in theAmericas and increased reports of birth
defects and Guillain-Barré syndrome in areas affected by Zika. On February 8, 2016,
CDC elevated its EOC activation to a Level 1, the highest level.

24. 24
Zika
• Since 2015, 69 countries and territories reported evidence of vector-borne Zika
virus transmission.
• Brazil is by far the most affected country, reporting the most cases of people
infected with the Zika virus.As of September 2016, some 1,949 confirmed cases
of Zika-related microcephaly in newborns were reported.
• In the U.S., there were over 3,000 Zika virus infections reported up to September
2016.
• On 18th Nov 2016, WHO commits to sustained and robust long-term response to
Zika as ‘public health emergency’is lifted.

25. 25

26. 26
Malaysian Nipah virus epidemic 1998-1999
• An outbreak of Nipah virus in Malaysia and Singapore
• Nipah virus belongs to family Paramyxoviridae
• Virus aerosolisation caused infection of pigs
• Overcrowding results in viral transmission to pig handlers
• The virus persists in low numbers in the island flying fox (Pteropus hypomelanus), a type
of fruit bat and Malayan flying fox (Pteropus vampyrus)
• Of the 269 human cases of viral encephalitis associated with Nipah virus infection
reported in Malaysia in 1999, 108 were fatal (Ministry of Health Malaysia, 2001).

27. 27
Examples of Re-Emerging Infectious
Diseases
• 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)

28. 28
Disease Year State
Plague 1994 Gujrat
2002 H.P.
2004 Uttranchal
Leptospirosis 1988-2004 Andaman & Nicobar
1994-2004 Gujrat
1984-1986 Tamil Nadu
1999-2003 Kerala
2000-2002 Maharastra
Anthrax 1999 Karnataka
2000 WB
2001 Karnataka
2003 Orissa

29. 29
Dengue/DHF 1996 Delhi
2003 Delhi & Kerala
2004 Kerala, Sikkim
Scrub typhus 2003 H.P
2004 Darjeeling, Sikkim
JE Yearly U.P, A.P,Haryana
Unknown acute viral 2001 Siliguri
encephalitis 2002 Saharanpur,A.P
2003 Karnal, Maharastra

30. 30
Antibiotic resistance
• Emerge in environment due to inappropriate use of antibiotic
• WHO estimates that 10 million people are dying of infectious diseases related to
antibiotic resistance.
• Proper antibiotic guidelines needed to prevent the drug resistance.

31. 31
Multi-resistant pathogens
Staphylococcus aureus is the most frequently identified drug-resistant pathogen.
Singhal et al (2007)reported ciprofloxacin-resistant meningococci in an outbreak
in Delhi.
Resistance of Salmonella typhi and S. paratyphi to chloramphenicol, ampicillin
and cotrimoxazole is widespread.
AMR in Shigella: resistance to azithromycin, ceftriaxone and ciprofloxacin on
the increase
Methicillin/oxacillin-resistant Staphylococcus aureus (MRSA)

32. 32
Vancomycin-resistant enterococci (VRE);
Extended-spectrum beta-lactamases (which are resistant to cephalosporins &
monobactams) (ESBLs);
Penicillin-resistant Streptococcus pneumoniae (PRSP);
Multi-drug resistant tuberculosis (MDR-TB);
CRKP- Carbapenem Resistant Klebsiella Pneumoniae
S. typhimurium - DT104 (resistant to five antibiotics: ampicillin, chloramphenicol,
streptomycin, sufonamides and tetracycline)

33. 33
Bioterrorism
• 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
• Highest potential- B. anthracis, C. botulinum toxin, Y
. pestis, Variola virus, Viral
haemorrhagic fever viruses
• Likeliest route- aerosol dissemination

34. 34
Control of Emerging and Re-emerging Diseases
• Controlling the reservoir
• Interrupting the transmission
• Protecting the susceptible host
• Strengthening of the disease surveillance system
• Encouraging research initiations for treatment regimens and diagnostics
• Encouraging research for new methods of control measures
• Establishment of drug resistance

35. 35
Role of Doctors in Prevention
Increase knowledge and skill ; Educate the public
Encourage partnerships with consumers and other disciplines to identify needs, set
priorities, develop strategies and evaluate progress
Support health care legislation
Involve in research
Encourage using multidisciplinary efforts.
Influence local and National economic and political options
Continue to advance nursing concern

36. 36
Role of Public Health Authorities
National programme for prevention and control of vector borne diseases
Legislations for elimination
Communities awareness of the disease
Minimizing transmission of infection: By
• Risk communication to the family members
• Minimizing vector population
• Minimizing vector – individual contact
Reporting to the nearest public health authority

37. 37
Public health measures to prevent infectious
diseases
Safe water
Sewage treatment and disposal
Food safety programme
Animal control programme
Vaccination programme
Public health organization

38. 38
Response of the WHO
• Developing global and regional strategies
• Appointing Task Force
• Generous grant from WHO regular budget
• Support the World Bank grant
• GOARN (Global OutbreakAlert & Response Network)
• Mechanism for combating international disease outbreaks
• Ensure rapid deployment of technical assistance, contribute to long-term epidemic preparedness &
capacity building

39. 39
VECTOR SURVEILLANCE
o Vector borne epidemic prone diseases: JE, Dengue, Plague, KalaAzar, Rickettsial
o
o Early warning signals
- increase density of vectors
- increase in breeding sites for vectors
Insecticide susceptibility status
o To assess impact of routine measures under national programme
PREVENTIVE STRATEGY IN INDIA

40. 40
LAB SURVEILLANCE
Serological Surveillance
To collect baseline prevalence data
To identify high risk areas
To identify high risk age group
As early warning signal for impending outbreak
Microbial surveillance
Changing genotype
Mutations
Development ofAntimicrobial Resistance
Eg. Salmonella, Cholera, Plague,Anthrax

41.  International (Collaborating Centres)
like CDCAtlanta
 National Reference Laboratories e.g.
NICD Delhi, NIV Pune, NICED
Kolkata
 State laboratories
 Intermediate
(District/Provincial/Medical College)
 Peripheral (PHC/CHC)
State Laboratories
National Laboratories
District Laboratories
Peripheral Laboratories
40
Laboratories network in surveillance

42. Peripheral
laboratories
District laboratories
Disease
Surveillance unit
Disease
Surveillance unit
Disease
Surveillance unit
National laboratory
State
laboratories
Disease
Surveillance unit
ACTION
42

43. 43
Peripheral Laboratories: Functions
• Collection of specimen
• Preliminary Processing Storage and transport
• Reporting of results
• Undertaking simple tests
• Microscopy for malaria, TB, meningitis, dysentery/Cholera
• Rapid Tests (Typhi Dot for enteric fever, Latex test for HBsAg
• Water Quality Monitoring by rapid H2S Test

44. 44
District Laboratories: Functions
• Microscopy for diphtheria, kala azar, Cholera
• Bacterial Cultures for enteropathogens, Enteric fever
• Antimicrobial Susceptibility testing
• Serological tests: Widal test, Latex test for meningitis in CSF, ELISAbased test
• Bacteriological examination of water (rapid H2S, coliform count)
• Coordinate with state/ national laboratory and disease surveillance units

45. 45
State Laboratories: Functions
• All that is done at district lab+ Specialized microscopy like dark ground,
fluorescent microscopy
• Culture of all common bacteria including mycobacteria and their identification (&
serotype, wherever applicable)
• Antimicrobial susceptibility testing of common bacteria including mycobacteria
• Serology for viral hepatitis markers, dengue, JE, measles, leptospirosis etc.
• ?Viral cultures
• QualityAssurance (IQC & EQAS)

46. 46
National Laboratories: Functions
• Specialized tests eg for Plague,Anthrax and other possible agents of bioterrorism
• High Containment laboratory (P3/ BSL--3)
• Assist in outbreak investigation
• Confirm new isolates
• All types of Lab based epidemiological markers
• Training/Preparation of Teaching Material and reagents/antisera etc
• Organize external quality assessment schemes
• Collation of national data

47. 47
Laboratory diagnosis of the emerging / re-emerging
infections
 Importance of laboratory diagnosis
• The results will alter clinical or infection control management, or as needed for public
health surveillance purposes.
• For infectious diseases, modern serological techniques, more and more based on
recombinant antigens, are being proven to be specific, rapid and less labor intensive.
• PCR may prove very useful and rapid test.
• Conventional methods turned out to be either too insensitive (e.g., during the
asymptomatic stage of HIV infection), too slow (e.g., mycobacterial culture) or too
cumbersome to be used on a large scale (e.g., virus isolation).

48.  Recommended laboratory testing in emerging infections
• Molecular testing- PCR- highly sensitive and specific
• Rapid test – for flu- need to confirm with PCR
• Dengue-NS1 antigen (indicated for case < 5 days)
• Antimicrobial resistance-susceptibility testing , gene detection by PCR
48

49. 49
Key Tasks in Dealing with Emerging Diseases
• Surveillance at national, regional, global level
• epidemiological,
• laboratory
• ecological
• anthropological
• Investigation and early control measures
• Implement prevention measures
• behavioural, political, environmental
• Monitoring, evaluation

50. 50
Solutions
• Strengthen international surveillance networks to issue early warning, detect, control, and
reduce emerging infectious diseases.
• Improve international public health infrastructure e.g. special laboratory that capable of
accurate and rapid diagnosis.
• Improve international capabilities to respond to disease outbreaks with adequate medical
and veterinary resources and expertise.
• Strengthen international research efforts on emerging infectious diseases, giving priority
to antibiotic-resistant strains of diseases.

51. 51
• Focus attention and resources on training and developing medical and veterinary
capability.
• Encourage national governments to improve their public health care systems, devote
resources to eliminating or controlling causes of emerging infectious diseases and
coordinate public health activities with WHO and other international communities.
• Develop better international standards, guidelines and recommendations.
Solutions (cont.)

52. Factors affecting emerging
infections
Solution
Migration Proper health screening, vaccination
Travel Immunization, infection control measure
Urbanization Proper sanitation, adequate housing, good infrastructure
Human behaviour Education, behaviour modification
Antibiotic usage Judicious use of antibiotic
Correct antibiotic for correct pathogen (with right
dosage and route).
Strengthen infection control measures 51
Solutions (cont.)

53. 53
Solutions (cont.)
 Public health surveillance & response systems
• Rapidly detect unusual, unexpected, unexplained disease patterns
• Track & exchange information in real time
• Response effort that can quickly become global
• Contain transmission swiftly & decisively
 Internet-based information technologies
• Improve disease reporting
• Facilitate emergency communications
• Dissemination of information

54. 54
Solutions (cont.)
Human Genome Project
• Role of human genetics in disease susceptibility, progression & host response
• Microbial genetics
 Methods for disease detection, control & prevention
• Improved diagnostic techniques & new vaccines
• Geographic Imaging Systems
Monitor environmental changes that influence disease emergence &
transmission

55. Key tasks - carried out by whom?
National
Regional
Global
55
Synergy

56. What skills are needed?
Multiple expertise needed !
Infectious
diseases
Epidemio-
logy
Public
Health
International
field
experience
Information
management
Laboratory
Telecom. &
Informatics
56

57. 57
Conclusion
• The true prevalence of many diseases is not known. Since we live in a global village,
we cannot afford to be complacent about the tremendous economic, social and
public health burden of these diseases. Effective surveillance is the key to their early
containment.
• There is a need to develop epidemiology improved diagnostic facilities, a strong
public health structure, effective risk communication, epidemic preparedness and
rapid response.

58. 58
References:
• Public Health and Preventive Medicine. MAXY-ROSENMAN-LAST, 15th edition.
• Oxford textbook of Public Health 6th edition.
• Park text Book of Preventive & Social Medicine. 23rd edition
• EMERGING INFECTIOUS DISEASES IN SEAR. WHO1998.
• WHO GLOBAL STRATEGY FOR CONTAINMENT OFANTIMICROBIAL RESISTANCE.
Executive summary.2001.
• CDC website: https://www.cdc.gov/vhf/ebola/about.html
• Preventing Emerging Infectious Diseases:AStrategy for the 21st Century. Overview of the Updated
CDC Plan
• Review of the emerging infectious disease problem And strengthening of epidemiological surveillance.
Forty fourth meeting of the regional director within WHO representative, New Delhi, 1995.
• Forty-fifth Meeting of the Regional Director with the WHO Representatives, New Delhi 4 to 13
November 1996 SEA/WR45/5. Emerging and re-emerging diseases, including tuberculosis and
malaria.

59. 59
Take Home Massage
• Community health is the pivot of Global health.
Let us join our hands on creating an awareness to
the individual family and community through
effective risk communication.

60. 60

61. Emerging Infectious Diseases: A
Research Approach
61

62. Benefits of Research on Emerging
Diseases
62

63. HUMAN
ANIMALS
ENVIRONMENT
VECTORS
Population
Growth
Mega-cities
Migration
Pollution
Exploitation
Climate change
Vector
proliferation
Vector
resistance
Transmission
Antibiotics
Intensive farming
Food
production
63

64. 64
Entero hemorrhagic Escherichia coli
• Causes no signs of illness
• Low infections dose in humans causes hemorrhagic colitis and hemolytic uremic
syndrome
• Consumption of undercooked beef and contaminated vegetables, fruits and water
for vegetarians.
• Reported in 1.4% of stools from cases of bloody diarrhea in Kolkata (Ministry of
Health and Welfare 2006).

65. 65
Disadvantages of PCR:
• Expensive-need special rooms, expensive reagent
• proper packaging of sample to prevent leaking, risk of contamination
• Immediate transportation as the microorganism eg RNAvirus is labile
• Need experience and well trained staff

66. 66
Vibrio cholerae
• Cholera is one of the oldest recorded infectious diseases.
• Pacini in 1854, first described comma shaped bacteria
• Robert Koch in 1883, showed the causative agent V .Cholerae.
• Das and Gupta -2005 reported the diversity of V .Cholerae.
• Narang et al (2008) described the changing patterns of V .Cholerae.

67. 67
Campylobacter spp
• Are significant zoonotic poultry pathogens
• Leading cause of gastro enteritis in the world
• Around 2.5 million human infections are reported annually in the
United States.
• In developing countries the presence of the organism was reported in
5-20% in childhood diarrhea

68. Trends in Malaria in SEA Region,
1976-2002
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
Year
Cases
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
Pf
Percentage
Total Malaria Cases Pf %
68

69. P.falciparum Resistance to
Antimalarials in WHO SEA Region, 2002
#
N e p a l
#
B a n g la de s h
#
My a n m a r
#
T ha ila n d
#
Ind o n e sia
E a st Tim o r
#
S ri L an k a
#
Ma ld iv e s
#
B h u ta n
In d ia
D P R Korea
N
E
W
S
Antim a lar ials
C Q
C Q + S P
C Q + S P + M E F
P. falciparum Resistance to Antimalarials in
W H O SEA Region, 1999
69