The document discusses various emerging and re-emerging infectious diseases, their causes, and examples. It defines emerging infectious diseases as newly identified infectious agents and re-emerging diseases as known agents that were previously under control but are increasing. The document then examines biological, environmental physical and social factors that influence disease emergence. It provides examples of transmission routes and recently emerging diseases such as Ebola virus, influenza, SARS, West Nile virus, monkeypox, and dengue. Tables list Ebola outbreak case counts by country and emerging infections and locations in India from 1990-2006.

1. Environmental aspects of
Emerging diseases
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2. Emerging infectious disease
Newly identified & previously unknown
infectious agents that cause public health problems
either locally or internationally
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
Definition
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3. Factors studied Examples
1. Biological----------Genes, microbes, medicines, vaccines, blood
and organ transplants, rapid microbial adaptation and resistance to
antibiotics
2. Environment: physical--------Air, water, toxins, radiation,
pollution, noise, agricultural development, climate change,
technology
3. Environment: social ---------Housing, education,
employment, and working conditions
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4.  Inhalation
 Ingestion
 Sneezing
 Coughing
 Food, water, soil
 Percutaneous inoculation
 Exposure to blood and body
fluids
 Direct animal contact
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5. Science: Pathways for Diseases in Humans
Infectious
Pets Livestock
Wild
animals Insects Food Water Air
Fetus and babies
Other humans Humans
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6. Examples of recent
emerging diseases
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7.  Ebola virus disease (formerly known as Ebola hemorrhagic
fever) is:
 A disease caused by the Ebola virus
 Is severe- fatality rate 90%
 Affects human and non human primates
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8. History of Ebola virus
• Ebola first appeared in 1976 in two simultaneous
outbreaks.
- Near the Ebola River in the Democratic
Republic of Congo
- A remote area of Sudan.
• 1975 cases
• 1069 deaths
• From Guinea, Liberia, Nigeria, and
Sierra Leone ( WHO 2014/8/14)
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9. Signs and symptoms
Fever and no response to treatment
for usual causes of fever in the area.
Muscle pain
Abdominal pain
Rash
Sore throat
General body weakness
Vomiting
Bleeding
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10. Ebola Hemorrhagic Fever
Ebola (5 species)
• Sudan
• Zaire
• Ivory Coast
• Reston Agent
• Uganda
First appearance in 1976
Sporadic outbreaks
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11. Country
Total Cases (Suspected,
Probable, and Confirmed)
Laboratory-Confirmed
Cases Total Deaths
Guinea 3175 2781 2101
Liberia 9265 3153 4057
Sierra Leone 11341 8308 3479
Total 23781 14242 9637
2014 Ebola Outbreak in West
Africa - Case Counts
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12. EBOLA
• This is a severe viral illness caused by the
Ebola virus (Filoviridae family) with its
reservoir in Fruit bats ,chimpanzees and
gorillas
• Symptoms: sudden onset of fever, myalgia,
headache, followed by vomiting, diarrhea,
and rash.
• Mortality: from 50 to 90 % in Africa
• Complications: In severe forms, multi organ
failure occurs, primarily hemorrhagic and
pulmonary complications
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13.  The virus is transmitted to people
from wild animals and spreads in the
human population through human-to-
human transmission.
 Fruit bats of the Pteropodidae family
are considered to be the natural host
of the Ebola virus.
Fruit bats transmitted to people
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14. EBOLA
• Mode of transmission: handling
infected wild animals
• Incubation period: 2 to 21 days
• Transmission: may be spread person
to person by contact with body
secretions
• Treatment: supportive
• Prevention: caution in contact with
infected monkeys and Fruit batsNEETHU ASOKAN

15. Swine Flu
Influenza A (H1N1)
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16.  H1N1, which caused Spanish Flu in 1918, and Swine Flu in
2009
 H2N2, which caused Asian Flu in 1957
 H3N2, which caused Hong Kong Flu in 1968
 H5N1, which caused Bird Flu in 2004
 H7N7, which has unusual zoonotic potential[35]
 H1N2, endemic in humans, pigs and birds
 H9N2
 H7N2
 H7N3
 H10N7
 H7N9
Influenzavirus A
Influenzavirus B
Influenzavirus A
Influenzavirus C
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17. Neuraminidase (N)
Hemagglutinin (H)
RNA
(highly mutagenic)
M2 protein
(only on type A)
Influenza Surface
Proteins
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18. Highly Pathogenic Avian
Influenza (H5N1)
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19. Major Influenza Pandemics
of the Twentieth Century
Major Years Subtype
Excess US
Mortality
’17-’18 H1N1 550,000
’57-’58 H2N2 70,000
’68-69 H3N2 36,000
NEXT? H5N1 (Avian) ?
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20. SARS
(SEVERE ACUTE RESPIRATORY SYNDROME)
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21. SARS-BASIC FACTS
• SARS is an illness which can vary in
severity and is caused by a Corona virus
most likely of animal origin, e. g. civet
• The disease is spread by large respiratory
droplets from sneezing and coughing within
a radius of 6 to 8 feet.
• Incubation period-3 to 10 days
• It can survive on surfaces up to 3 days but
is easily killed by standard disinfectantsNEETHU ASOKAN

22. Treatment
Antibiotic therapy
 Levofloaxacin 500 mg daily once
 Clarithromycin 500 mg daily twice
Antiviral therapy
 Ribavirin
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23. WEST NILE VIRUS
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24. FACTS ABOUT WNV
• West Nile Fever is a “flu-like” illness of
sudden onset, caused by a subgroup of
viruses called Flavoviruses
• Symptoms: fever, sore throat, headache,
malaise, arthralgia or myalgia. Rash is
common.
• Complications: meningitis or encephalitis
(inflammation of the brain tissue or the
covering of the brain) can occur. The
disease is then named West Nile
neuroinvasive disease
• Reservoir: certain birdsNEETHU ASOKAN

25. Transmission of WNV Without Mosquitoes
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26. FACTS ABOUT WNV
• Incubation period: usually 3 to 12 days
• Communicability: no direct person to person
transmission
• Mode of transmission: the bite of an
infected mosquito
• Prevention: Mosquito eradication, mosquito
repellents
• Treatment: none specific
• Mortality rate: 3 to 15%
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27. MONKEY POX
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28. MONKEY POX
• Monkey pox, an Orthopox virus caused
infection, closely resembles small pox
clinically
• Recently transmitted to humans by prairie
dogs infected by a Gambian giant rat
imported from Africa
• Symptoms: fever, rash, muscle aches, cough
• Mortality: 1 to 10% in Africa, none in the
US
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29. MONKEY POX
• Transmission: person to person has
occurred
• Treatment: antibiotics, small pox
vaccination if early in the course of the
disease
• Prevention: small pox vaccination is
partially successful, public education
about the dangers of illegally imported
pets
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30. Dengue Endemic Areas
(1996 to 2010 = 29 States/UTs)
Risk factors:
• Construction
activities
• Water storage
practice
• Population
movement
• Heavy rainfall
• Vector abundance
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32. WHAT IS DENDUE ?
 Dengue is a viral disease
 It is transmitted by the infective bite of female Aedes
Aegypti mosquito
 Man develops disease after 5-6 days of being bitten by an
infective mosquito
 It occurs in two forms: Dengue Fever and Dengue
Haemorrhagic Fever(DHF)
 Dengue Fever is a severe, flu-like illness (Influenza)
 Dengue Haemorrhagic Fever (DHF) is a more severe form of
disease, which may cause death
 Person suspected of having dengue fever or DHF must see a
doctor at once NEETHU ASOKAN

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34. Chikungunya
 Chikungunya is an infection caused by the chikungunya virus. The
disease features the sudden onset of fever two to four days
after exposure.
 Chikungunya virus, also referred to as CHIKV, is a member of
the alphavirus genus, and Togaviridae family. It is an RNA
virus with apositive-sense single-stranded genome of about
11.6kb.
 The fever usually lasts two to seven days, while
accompanying joint pains typically last weeks or months but
sometimes years.
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35. Transmission
 Chikungunya is generally transmitted from mosquitoes to humans. Less
common modes of transmission include vertical transmission, transmission
from mother to child during pregnancy or at birth.
 Transmission via infected blood products and through organ donation is
also theoretically possible during times of outbreak, though no cases have
yet been documented.
 Chikungunya is related to mosquitoes, their environments, and human
behavior.
 Chikungunya is spread through bites from Aedes mosquitoes, and the
species A. aegypti was identified as the most common vector, though the
virus has recently been associated with many other species, including A.
albopictus.[
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36. Vaccine
 Currently, no approved vaccines are available. A phase-II vaccine trial
used a live, attenuated virus, to develop viral resistance in 98% of those
tested after 28 days and 85% still showed resistance after one year.
Treatment
 Currently, no specific treatment for chikungunya is available.
 Supportive care is recommended, and symptomatic treatment of fever
and joint swelling includes the use ofnonsteroidal anti-inflammatory
drugs such as naproxen, non-aspirin analgesics such
as paracetamol (acetaminophen) and fluids.
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37. S.NO EMERGING INFECTIONS COUNTRY
1 Ebola hemorrhagic
Fever
Zaire,Gabon
2 Dengue hemorrhagic fever Western hemisphere,
3 Venezuelan equine
Encephalitis
Venezuela and colombia
4 Cholera Cape verde
5 Meningococcal meningitis Africa
6 Lassa fever Sierra leone
7 Streptococcus iniae infection Canada
8 Variant creutzfeldt- jakob disease United kingdom,france
9 Vancomycin intermediate –sensitive
and resistant staphylococcus
aureus
(VISA/VRSA)
USA
10 Marburg virus disease Angola
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38. S.NO Year Infections Location
1 1990 Multidrug –resistant (ACCo) salmonella typhi Most Indian states
2 1991 Vibrio cholerae o139 Suoth India,west Bengal
3 1994 Plague Maharashtra and Gujarat
4 1996 Dengue hemorrhagic fever North india
5 2000 Faciolopsiasis Azamgarh, UP
6 2001 Acinetobacter baumannii Manipal, Delhi
7 2001 Pichia anomala Chandigarh
8 2001 Rotavirus G4P8 Kolkata
9 2001 Low level penicillin resistance in streptococcus
pneumoniae
Pondicherry, Delhi,Vellore
10 2002 West Nile virus Maharashtra,Rajasthan,Goa,Orissa
11 2003 Nalidixic acid –resistant Salmonella typhi Delhi, Mumbai
12 2005 Meningococcal meningitis Delhi,
13 2006 Avian influenza H5N1 Maharashtra
14 2006 Chikungunya AP, Karnataka,TamilnaduNEETHU ASOKAN

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