emerging re-emerging infections

1. EMERGING &
RE-EMERGING
INFECTIONS
Dr. Sushrit A. Neelopant
Dept. of Community Medicine, RIMS,
Raichur
1

2. Introduction
 Modern medical discoveries - Remarkable progress
in the prevention, control and even eradication of
infectious diseases.
 Improved hygiene and development of antimicrobials
and vaccines.
 The theme of the World Health Day – 1997
"Emerging Infectious Diseases - Global Alert :
Global Response"
2

3. Historical perspectives
 The BLACK DEATH (1348 – 50 ): The most
devastating pandemics in human history.
Plague had eliminated as much as a third of the
European population !!!
 1520 -21: Smallpox microbes carried by explorers
were responsible for 10-15 million deaths in
effectively ending Aztec civilization.
 Other Amerindian and Pacific civilizations were
destroyed by imported small pox and measles.
3

4. Historical perspectives
 The eradication of smallpox
 Improved sanitation, clean water and better living
conditions along with vaccines and antimicrobial
agents – changed the world
4

5. Definition
EMERGING INFECTIOUS DISEASES (EID’s):
 Diseases of infectious origin whose incidence in
humans has increased within the recent past or
threatens to increase in the near future.
 New disease – New problem
 The term also refers to newly-appearing infectious
diseases, or diseases that are spreading to new
geographical areas.
(Ex: Cholera in South America and yellow fever in
Kenya.)
5

6. Definition
RE-EMERGING INFECTIOUS DISEASES (RID’s) :
 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
 Old disease – New problem
 Ex: Tuberculosis  MDR, XDR TB.
Malaria  ACT Resistant Malaria
Cholera 01  0139
Kala azar, Chikungunya, etc.,6

7. Why study the emergence ?
 A strong health system - Prerequisite for effectively
combating emerging infectious diseases.
 New emerging infections–disrupt the health care
system.
 Today’s emerging diseases can assume pandemic
proportions causing social and economic disruption
and ultimately becoming endemic.
 Ex: HIV/AIDS :
Remote part of Africa  all other continents  the
world. Within 25 years from its first isolation it has
become the 4th leading cause of death worldwide.
(No.1 in India)7

8. New diseases – New threats
 30 new infectious agents have been detected
worldwide in the last three decades;
 60 % of these are of Zoonotic origin, and
 > 2/3rd of these have originated in the Wildlife
 23 % are vector borne.
 heavy toll of life and by rapidly spreading across
borders
8

9. Newly discovered microbes (1970 - 1990)
9

10. Newly discovered microbes (1991 - 2012)
10

11. Classification of New Diseases
11
 National Institute of Allergy and Infectious
Diseases classified emerging infections.
 3 groups.
1. Pathogens Newly Recognized in the Past 2
decades
2. Re-emerging Pathogens
3. Agents with Bioterrorism Potential
Category A, B & C

12. Classification
(NIAID)
GROUP I - Pathogens Newly Recognized in the Past
Two Decades
 Acanthamoebiasis
 Australian bat lyssa virus
 Babesia, Atypical Bartonella henselae, Ehrlichiosis,
 Encephalitozoon cuniculi, hellem, bieneusi,
 Helicobacter pylori, Hendra or equine morbilli virus,
Hepatitis C & E,
 Human Herpes Virus 8 & 6, Lyme borreliosis,
 Parvovirus B19
12

13. Classification
National Institute of Allergy and Infectious Diseases (NIAID)
Group II - Re-emerging Pathogens
 Enterovirus 71,
 Clostridium difficile,
 Mumps virus,
 Group A Streptococcus
 Staphylococcus Aureus
 Tuberculosis (MDR, XDR)
 Malaria (ACT Resistant)
13

14. Group III - Agents with Bioterrorism Potential
CATEGORY A
 Yersinia pestis (plague)
 Variola major (smallpox) and other related pox viruses
 Bacillus anthracis (anthrax)
 Francisella tularensis (tularemia)
 Clostridium botulinum toxin (botulism)
CATEGORY B
 Brucellosis (Brucella spp.)
 Epsilon toxin of Clostridium perfringens
 Staphylococcal enterotoxin B
 Food safety threats (e.g., Salmonella, Escherichia coli
0157:H7, Shigella)
 Water safety threats (e.g., Vibrio cholerae, Cryptosporidium
parvum)
CATEGORY C14

15. Global burden
 The emerging infectious diseases account for 26 %
of annual deaths worldwide.
 Nearly 30 % of 1.49 billion - DALYs lost every year
 The burden of morbidity and mortality - Developing
countries, and particularly on infants and children
(≈ 3 million children die each year from malaria and
diarrhoeal diseases alone).
15

16. Global burden
 Distribution of these pathogens by groups shows:
 37 % are Viruses and Prions
 25 % are Protozoa.
Indicates that emerging and re-emerging pathogens
are predominantly viruses
16

17. Recent emerging infectious diseases
17
Source: THE NATURE; Vol 430; July
2004.

18. Emerging diseases in SEARegion
18

19. Burden in India
 INDIA –
 3 matrix diseases – TB, HIV & Malaria (MC Inf. Ds.)
 Zoonotics – Brucellosis, Anthrax, Rabies, etc.,
 Home of emerging vector borne diseases - Dengue,
Chikungunya, Acute Encephalitis Synd.(AES)/ JE.
 Emergence of new Vibrio Cholerae 0139
 Re-emergence of Leptospirosis.
 Emergence of drug resistant strains – MDR, XDR
TB, MDR Typhoid, MRSA.
19

20. 20

21. Epidemiological Trends
 The microbial world is COMPLEX, DYNAMIC and
CONSTANTLY EVOLVING.
 Infectious agents reproduce rapidly, mutate
frequently, cross the species barrier between animal
and human hosts and adapt with relative ease to
their new environment
 These traits – led to alter their
Epidemiology,
Virulence,
Susceptibility.
21

22. Features of Emergence
Include new, previously undefined diseases as well
as old diseases with new features.
 New location
 New population
 New age group
 New clinical features
 Resistance to available treatments
 Rapid increase in the incidence and spread of
the disease.
 New recognition of Infectious agent
 Realization that established condition has
infectious origin.
22

23. Chronic diseases with infectious etiology
23
Microbe Disease
Helicobacter pylori Peptic ulcer, gastric
carcinoma
HPV Cervical, Vulvar carcinoma
HBV / HCV Liver Cirrhosis, Hepatic Ca.
EBV B-cell lymphoma,
Nasopharyngeal Ca.
HTLV Type 1 Adult T-cell Leukemia
Human Herpes Virus 8 Kaposi Sarcoma
Borrelia burgdorferi Lyme Arthritis
Tropheryma whippelii Whipple’s disease
Chlamydia pneumoniae Atherosclerosis

24. Epidemiology
ONION PEEL PHENOMENON
 Old diseases fade away
giving place to the new ones
 Layers of the onion 
the waning diseases
 Infectious ones will be
replaced by non–infectious
ones to be replaced later and
also with new emerging and
old re-emerging diseases.
24

25. Factors - Emergence and Re-emergence of diseases
Factors Categories Examples
AGENT MICROBIAL
ADAPTATION
(GENETIC)
Changes in virulence and toxin
production
Development & change in Drug
Resistance
Microbes as a co-factor for chronic
diseases
HOST SOCIETAL EVENTS Population growth / Migration
War / Civil Conflict
Economic impoverishment
HEALTH CARE New Medical Devices
Tissue / Organ Transplantation
Irrational use of Antibiotics
FOOD PRODUCTION Changes in food processing / Packing
Globalization of Food supplies
HUMAN BEHAVIOUR Sexual behaviour
Drug abuse / Habits
25

26. Factors - emergence and Re-emergence of diseases
Factors Categories Examples
ENVIRON -
MENT
ENVIRONMENTAL
CHANGES
Deforestation/ Reforestation
Changes in water ecosystem
Flood / Drought / Famine
Global Warming
PUBLIC HEALTH Curtailment or reduction in prevention
programme
Inadequate infrastructure
Inadequate communicable disease
surveillance
Lack of trained personnel
26

27. Impact of new disease
 Epidemics or pandemics caused by these emerging
and re-emerging infections often take a heavy toll of
life and by rapidly spreading across borders are
responsible for much concern and panic.
 Grave challenge – Health, Economic condition,
Development and Security of the world.
 Consume huge share of health care resources,
Divert from endemic disease problems,
Results in productivity loss,
Decreased trade and tourism revenue.
27

28. Direct economic impact of selected infectious
disease outbreaks, 1990-2003
Emerging and re-emerging infections. Oxford Textbook of Public Health, 5th28

29. Emergence & Re-emergence
 New diseases in developed countries
Ex: HIV (Kaposi’s), Legionnairre’s disease, Hepatitis
B & C
 Old diseases in developed countries
Ex: Tuberculosis (MDR, XDR)
 New diseases in developing countries
Ex: Ebola Hemorrhagic fever, AIDS, H5N1, H1N1.
 Old diseases in developing countries
Ex: Malaria & TB (Drug resistant), Poliomyelitis, JE,
Scrub typhus, Anthrax, Dengue, Chikungunya.29

30. Recent outbreaks in India
o 1992 – Cholera (Chennai)
o 1994 – Plague (Surat)
o 1997 – Leptospirosis (Mysore, Nagpur, Gujarat)
o 2000 – Diphtheria (Delhi) Leptospirosis (Mumbai, Kerala)
o 2001 – Nipha virus (Siliguri)
o 2002 – Plague (Shimla)
o 2003 – Chandipura virus (Andhra Pradesh)
o 2004 – Plague (Uttarakhand), Chandipura (Gujarat)
o 2005 – Chikungunya (Andhra Pradesh)
o 2006 – JE (Muzzafarnagar)
o 2007 – Chandipura virus (Maharashtra) Chikungunya
(Kerala)
o 2009 – H1N1 (Pune, Hyderabad)
o 2010 – Dengue (Delhi), JE (Muzzafarnagar)
o 2011 – Crimean Congo Hemorrhagic fever (Gujarat)30

31. 31
 2014 Odisha jaundice outbreak.
 2015 Indian swine flu outbreak.
 2017 Zika
 2018 Nipah virus outbreak in Kerala.

32. Cholera - 1992
 A large scale cholera outbreak occurred in India in
December1992, starting in southern peninsular
India (Chennai) and spreading both inland and along
coast line of Bay of Bengal.
 Vibrio cholerae O139, a new serogroup was
associated with this epidemic cholera.
 Pecularities : Change in antigenic structure such that
there is no existing immunity, all ages (older adults)
and people in endemic areas are also susceptible.
32

33. Plague – 1994, 2002, 2004
 1896 – 1st case in Mumbai (Since then has caused
12 million deaths)
 After last lab confirmed case from Karnataka (1966)
 The 1994 ‘Pneumonic Plague’ outbreak in Surat in
Maharashtra State created an unprecedented level
of panic  population exodus and internal
migration, near international isolation of India
 Considerable negative social, political, and economic
impact contributed in part by local and international
media reports.
 896 sero-positive cases, 54 deaths reported.
33

34. Plague
 Plague infection continues to exist in “sylvatic foci” in
many parts of India which is transmitted to humans
occasionally.
 The National Centre for Disease Control (NCDC) has
identified four ‘sylvatic foci’ in India;
1. Tri-junction of Karnataka, Andhra Pradesh and Tamil
Nadu,
2. Beed belt in Maharashtra,
3. Rohru in Himachal Pradesh and
4. Uttarakhand25.
34

35. Diphtheria - 2000
 The incidence of diphtheria, a vaccine preventable
disease during 1980 was about 39,231, it reduced to
2817 cases in 1997
 In the past two decades – a sudden increase in
diphtheria cases with more than 8000 cases
reported in 2004.
 Possible etiology : The primary immunization
coverage for diphtheria has remained between 56 to
72 per cent in the past two decades according to
WHO UNICEF estimates.
 The 3 rounds of NFHS also show that DPT 3
coverage during 1992-2006 was only 52-55 %.
35

36. Leptospirosis
 Caused by Leptospira interrogans naturally seen in
rodents.
 These parasitise kidneys and are excreted in rat
urine.
 Man and cattle are incidental hosts – they get
infected by contact with water or soil contaminated
with rat urine.
 High Risk Group : Farm workers, sewer workers,
fishermen, miners
 1st described the disease in Andaman Islands, India.
[Taylor and Goyle (1931)].36

37. Nipah virus
 The Nipah virus was first recognized in 1999 during
an outbreak among pig farmers in Malaysia.
 Since then, there have been 12 additional outbreaks,
all in South Asia.
 Fruit bats of the Pteropodidae family are the natural
hosts for Nipah virus.
 Evidence shows that geographical distribution of
Henipavirus (Nipah and Hendra) overlaps with that
of Pteropus .
 Over the years, the epidemiology of Nipah appears
to have changed.
37

38. Nipah virus
 Evidence of person to person transmission and a
high case fatality rate (60-70%) were some of the
alarming developments seen in Nipah outbreaks in
India and Bangladesh
 Nipah virus has also been categorized as a food
borne disease from eating dates contaminated with
urine or saliva of infected bats.
38

39. Chandipura virus – 2003, 04, 07
 A new virus belonging to family Rhabdoviridae was
isolated in 1965 in the Chandipura (Nagpur) region
of India in two adult patients with febrile illness
(during an outbreak of febrile illness caused by
chikungunya and dengue viruses.)
 It was named as Chandipura (CHP) virus.
 CHP virus is transmitted to humans by sandflies .
39

40. Chikungunya fever – 2005,06,07…
 Chikungunya fever, caused by the CHIK Virus, was
first reported in Tanzania in 1953.
 Non-human primates act as a main reservoir of
infection.
 Vector borne – Aedes egypti or albopictus
 Previous outbreaks in India (1963 and 1973) were
caused by the Asian genotypes.
 2006 - A resurgence of infection from southern and
central parts of the country was reported been
attributed to the East African genotype
40

41. Chikungunya virus
41
 Currently, 22 States and
Union Territories of India
have reported cases of
chikungunya.
(NVBDCP, 2007)
 Although deaths are
rare but the morbidity
and disability caused
due to chikungunya are
enormous.

42. Avian influenza (H5N1)
 Avian influenza is an infection caused by Influenza A
(H5N1) viruses, usually infecting poultry animals and
pigs.
 First reported in 1997 in Hong Kong.
 2003 - Changes in the strains of virus resulted in
emergence ‘Novel’ Z strain and, infection to human
beings by this virus (contrary to earlier belief)
 Vietnam reported first human case in 2003.
 Till date 587 persons have been infected by
Influenza A (H5N1) with 346 deaths from 15
countries.
 Cases of bird flu were reported in Navapur tehsil of
Nandurbar district of Maharashtra.42

43. Avian Influenza H5N1
43
Documented human infections with avian influenza viruses, 1997–2004.
Source: http://www.who.int/csr/disease/influenza/en.

44. Origin of H1N1 Virus
44

45. Pandemic H1N1 Influenza
 The pandemic HINI influenza virus emerged in
humans in early April 2009 in Mexico and
California.
 Current virus – Quadruple reassortment of two
swine strains , one human and one avian strain
 Pandemic alert – by WHO on June 11, 2009
 Quickly spread worldwide – man-to-man
transmission.
 August 2010 – Worldwide more than 214
countries had reported laboratory confirmed
cases of pandemic influenza H1N1 2009,
including over 18449 deaths.
45

46. Pandemic H1N1 Influenza
 In India : Pandemic started by – August 2009
 Index cases reported in Pune and later spread to other
parts of the country.
 Epidemic notoriously affected the younger population in
the age group 15-40 years
 August, 2010, a total of 1,54,259 persons were
tested for H1N1 influenza and 23.4 % were found to
be positive including 1833 deaths.
 Transmission was intense in western States of
Maharashtra and Gujarat.
46

47. Distribution of pandemic H1N1
47

48. Crimean-Congo Haemorrhagic fever (CCHF)
 First described as a clinical entity in 1944-1945 in
Crimea during World War II.
 CCHF virus circulates in an enzootic tick-vertebrate-
tick cycle.
 The virus causes disease among smaller wildlife
species, e.g. hares and hedgehogs that act as hosts
for the immature stages of the tick vectors.
 A CCHF outbreak was reported in Gujarat in 2011.
 This outbreaks was characterized by a zoonotic
origin and a person-to-person spread in hospital
setting.
48

49. Crimean-Congo Haemorrhagic fever (CCHF)
 Major at-risk group : Farmers living in endemic
areas and animal handlers.
 Control : High index of clinical suspicion, early
laboratory diagnosis and institution of containment
measures
 The geographic range of CCHF virus is the most
extensive among the tickborne viruses that affect
human health.
 Resurgence : Changes in climatic conditions have to
be one of the factors that has facilitated the survival
of a large number of Hyalomma spp. Ticks  the
hosts of both their immature and adult stages 
increased incidence of CCHF.49

50. Acute Encephalitis Syndrome (AES)
 India : Of the 5 States reporting the disease during
2011, most cases and deaths were in Uttar Pradesh
> Bihar > Jharkhand > Assam > West Bengal.
 MC age group : Children below the age of 10 years.
 As a seasonal disease – AES often occurs in
outbreaks during summer or following the rains.
 Recent outbreak in Muzzaffarpur district of Bihar,
which began during May - July 2012 accounted for
389 cases and 160 deaths, with a case fatality rate
of 41.13%
 Characteristics: Most of the outbreaks, the
aetiological agents remain undetermined, with
Japanese Encephalitis virus detected in about 15 %50

51. Other emerging diseases in the World
 Dengue (DF, DHF)
 Ebola Hemorrhagic Fever
 Rift Valley Fever
 SARS Co-V
Recent Emerging diseases:
 Influenza A (H7N9) – China.
 Middle East Respiratory Syndrome Corona Virus
(MERS Co-V)  Middle East (Saudi Arabia, Jordan,
France, Germany, UK)
51

52. Prevention and control strategies
52

53. 1. Epidemic preparedness and rapid response
53

54. 2. Public health infrastructure including
laboratory capacity
 Public health infrastructure is the ‘backbone’ of any
efficient public health activity.
 It consists of people in the field:
 public health,
 epidemiology,
 entomology,
 environmental hygiene,
 infection control,
 laboratories
 IEC specialists at various levels
54

55. 3. Risk Communication
 Risk communication - is an interactive process of
exchanging information and opinion among
individuals, groups and institutions with the
overarching aim
 A well-informed community can provide immense
support to any public health intervention
 The objectives :
1. to ease public concern by informing them about the
risk, the transmission dynamics and clinical
features of disease outbreak
2. to make the public aware of actions that need to be
initiated by people themselves for their benefit.
55

56. 4. Research and its utilization
 Research can play an important role during an
outbreak,
 Identifying the etiological agent,
 Developing diagnostic tools,
 Case management modules
 Preventive strategies.
 Knowledge needs to be generated through research
and interpreted, evaluated and transferred to
improve practices for prevention and control of
emerging infectious diseases.
56

57. 5. Advocacy for political commitment and
building partnerships
 Efficient programme management demands strong
political will and commitment, adequate financial and
human resources as well as productive partnerships
with different sectors.
 Collaboration between government agencies is
easier and feasible - but challenging when the
private sector and mass media are to be involved.
 Develop consensus for a national policy with full
involvement of all concerned parties.
 Set-up a formal mechanism for
Intersectoral collaboration & public-private
partnership57

58. Strategies in India
 1994 – Central Council of Health and Family Welfare
(CCHFW) – the apex political and policy formulating
body with the Union Minister of HFW (chairman)
 1995 – recommendation for establishment of State &
Dist. Epidemiological Unit.
 1996 – National Apical Advisory Committee (NAAC)
for National Disease Surveillance and Response was
created.
 1997 - National Surveillance Programme on
Communicable Diseases (NSPCD)
 2004 – IDSP was launched in 101 districts. (now
covers entire country)
 2007 – Dept. of Health Research (Div. of MOHFW,58

59. GOARN
59
 Global Outbreak Alert & Response Network
 Coordinated by WHO
 Mechanism for combating international disease
 outbreaks
 Ensure rapid deployment of technical assistance,
contribute to long‐term epidemic preparedness &
capacity building

60. International Health Regulations 2005
60
 Public Health Emergency of International concern
 Epidemic alert and response
 National Focal Point
 Dictates the core requirements for:
– surveillance and response
– ports of entry

61. Summary
61
 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,
interspecies contacts, altered social conditions,
demography and medical technology affect
microbes’ opportunities.
 "Knowing is not enough; we must apply. Willing is
not enough; we must do.“ - Johann Wolfgang von
Goethe, German poet (1749‐1832)