This document outlines a post graduate seminar on epidemiological surveillance of dengue fever. It provides an outline of topics to be covered including introduction, history, distribution, epidemiology, vector, viral morphology, transmission, pathogenesis, public health significance, prevention and control, and conclusions. It identifies the major advisor, minor advisor, and speaker for the seminar.

1. A POST GRADUATE CREDIT SEMINAR
ON
“EpidEmiological survEillancE of dEnguE fEvEr:
an ovErviEw”
MAJOR ADVISOR
Dr. N.M. Shah
Rtd. Professor & Head,
Veterinary Microbiology
Veterinary College, S.D.A.U., Dantiwada
MINOR ADVISOR
Dr. J.S.PATEL
Professor & Head,
Veterinary Medicine,
Veterinary College, J.A.U.,Junagadh
Speaker:Speaker:
J. B. KathiriyaJ. B. Kathiriya
Reg. No. 1040416004
Ph.D. Scholar
DEPARTMENT OF VETERINARY MICROBIOLOGYDEPARTMENT OF VETERINARY MICROBIOLOGY
COLLEGE OF VETERINARY SCIENCE AND ANIMAL HUSBANDRYCOLLEGE OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY
JAU, JUNAGADHJAU, JUNAGADH
1

2. Dengue Fever

3. • INTRODUCTION
• HISTORY
• DISTRIBUTION
• EPIDEMIOLOGY
• VECTOR
• VIRAL MORPHOLOGY
• MODE OF TRANSMISSION
• PATHOGENESIS
• PUBLIC HEALTH SIGNIFICANCE
• PREVENTION AND CONTROL
• CONCLUSIONS
OUTLINE

4. 4

5. DENGUE FEVER
 Dengue fever is an acute infectious viral disease, major growing public health
problem also known as breakbone fever.
 It is an arthropod-borne (arboviral) illness in human .
 Several serotypes can be in circulation during an epidemic.
 Any serotype can cause severe / fatal disease.
 Some genetic variants within each serotype appear to be more virulent or
have greater epidemic potential.
 Infection with one dengue serotype confers lifelong homotypic immunity to
that serotype and a very brief period of partial heterotypic immunity to other
serotypes, but a person can eventually be infected by all 4 serotypes.

6. 6
Caused by any one of four
closely related dengue
viruses

7. 7
 A human may only become infected by Aedes Aegypti bite and a mosquito only
becomes infected by biting an infected human.
 Facts:
 Only the female mosquito feeds on blood, this is because they need the protein
found in the blood to produce eggs.
 On average mosquito can lay about 300 eggs during its life span of 14 to 21
days.
 Dengue can also be transmitted via infected blood products and through organ
donation.

8. DENGUE VIRUS= SMALL (50NM)VIRUSES
Electron Micrograms

9. 9At present DEN1 and DEN2 serotypes are widespread in India

11. 11

12.  1. Dr Benj amin Rush a prof essor of chemist r y and medical t heory at
t he Univer sit y of Pennsylvania, dur ing t he Philadelphia epidemic
1779 -1780, f ir st descr ibed t he dr amat ic sympt oms of dengue as
br eak bone f ever .
 2. A small per cent age of per sons who have pr eviously been inf ect ed
by one dengue ser ot ype develop bleeding and endot helial leak up on
inf ect ion wit h anot her dengue ser ot ype. This syndrome is t ermed
dengue hemorr hagic f ever (DHF). Also been t er med dengue
vasculopat hy.
 3. Vascular leakage in t hese pat ient s result s in hemo-concent r at ion
and ser ious ef f usions and
can lead t o cir culat ory collapse.
 4.This in conj unct ion wit h severe hemor r hagic complicat ions, can
lead t o

13. DISTRIBUTION Before 1970, only 9 countries had
experienced sever dengue
epidemics.
 The disease is now endemic in more
than 100 Tropical and subtropical
countries.
 Today about 2.5 billion people, or
40% of the world’s population, live in
areas where there is a risk of
dengue transmission.
 Pandemic began in South East Asia
after WW II with subsequent Global
spread. (Chaturvedi and Nagar, 2009)

14.  An estimated 5,00,000 cases of DHF require hospitalization each year, of
which a very large proportion are children. At least 2.5% of cases die
without proper treatment.
 A rapid rise in urban populations is bringing greater numbers of people
into contact with this vector, especially in areas that are favorable for
mosquito breeding, e.g. where household water storage is common and
where solid waste disposal services are inadequate.
(Halstead et al., 2007)

15. Few common and favoured breeding
places/sites of Ae. aegypti

16. INDIAN SCENARIOINDIAN SCENARIO
THE FIRST RECORDED EPIDEMIC OF CLINICALLY
DENGUE LIKE ILLNESS OCCURRED AT MADRAS IN
1780.
 FIRST OUTBREAK IN INDIAN SUBCONTINENT:
1812.
FIRST DENGUE VIRUS ISOLATION- KOLKATA IN
1943–1944.
FIRST OUTBREAK IN INDIA: 1963 IN KOLKATA.
(Jatanasen et al., 2016)

17. INDIAN SCENARIOINDIAN SCENARIO
RECENT DENGUE EPIDEMIC OCCURRED IN 1996, 2003, 2006,
2008, 2011,2013 & 2016.
IN 2008, 12,419 DENGUE CASES AND 80 DEATHS WERE
REPORTED.
IN 2016, 1,29,166 DENGUE CASES AND 245 DEATHS WERE
REPORTED.
IN 2017, 36,635 DENGUE CASES AND 58 DEATHS WERE
REPORTED TILL AUGUST-2017.
DELHI SHARES ~25% OF DENGUE DISEASE BURDEN OF
COUNTRY.
(Jatanasen et al., 2016)

18. Dengue Endemic Areas
(1996 to 2016 = 31 States/UTs)
Risk factors:
•Construction activities
• Water storage practice
•Population movement
•Heavy rainfall
•Vector abundance

19. 19
District-wise reported dengue cases in Saurashtra region of Gujarat
state during the year 2013
Mistry et al., 2013

20. 20

22. 22
“We found that India had
nearly 6m annual clinically
diagnosed dengue cases
between 2006 and 2012 –
almost 300 times greater
than the number of cases
that had been officially
reported,”
-said Prof Donald S
Shepard, health economics
professor at Brandeis
University, Massachusetts,
who led the five-year
research project.

23. 23
Current status of Dengue in India - Dengue Cases and Deaths in the Country
Sl.
No.
Affected
States/UTs
2010 2011 2012 2013 2014 2015 2016* 2017*
C D C D C D C D C D C D C D C D
1
Andhra
Pradesh
776 3 1209 6 2299 2 910 1 1262 5 3159 2 3417 2 1080 0
2
Arunachal
Pradesh
0 0 0 0 346 0 0 0 27 00 1933 1 13 0 3 0
3 Assam 237 2 0 0 1058 5 4526 2 85 0 1076 1 6157 4 331 0
4 Bihar 510 0 21 0 872 3 1246 5 297 0 1771 0 1912 0 18 0
5 Chattisgarh 4 0 313 11 45 0 83 2 440 9 384 1 356 0 38 0
6 Goa 242 0 26 0 39 0 198 2 168 1 293 0 150 0 150 0
7 Gujarat 2568 1 1693 9 3067 6 6272 15 2320 3 5590 9 8028 14 883 0
8 Haryana 866 20 267 3 768 2 1784 5 214 2 9921 13 2493 0 4 1
9
Himachal
Pradesh
3 0 0 0 73 0 89 2 2 0 19 1 322 0 5 0
10 J & K 0 0 3 0 17 1 1837 3 1 0 153 0 79 1 1 0
11 Jharkhand 27 0 36 0 42 0 161 0 36 0 102 0 414 1 187 0
12 Karnataka 2285 7 405 5 3924 21 6408 12 3358 2 5077 9 6083 8 5728 5
13 Kerala 2597 17 1304 10 4172 15 7938 29 2575 11 4075 25 7439 13 16530 28
14
Madhya
Pradesh
175 1 50 0 239 6 1255 9 2131 13 2108 8 3150 12 52 0
15 Meghalaya 1 0 0 0 27 2 43 0 0 0 13 0 172 0 6 0
16
Maharashtr
a
1489 5 1138 25 2931 59 5610 48 8573 54 4936 23 6792 33 718 3
* Provisional till 20th
Aug. 2017

24. 24
17 Manipur 7 0 220 0 6 0 9 0 0 0 52 0 51 1 36 0
18 Mizoram 0 0 0 0 6 0 7 0 19 0 43 0 580 0 36 0
19 Nagaland 0 0 3 0 0 0 0 0 0 0 21 1 142 0 0 0
20 Orissa 29 5 1816 33 2255 6 7132 6 6433 9 2450 2 8380 11 455 2
21 Punjab 4012 15 3921 33 770 9 4117 25 472 8 14128 18 10439 15 153 0
22 Rajasthan 1823 9 1072 4 1295 10 4413 10 1243 7 4043 7 5292 16 167 0
23 Sikkim 0 0 2 0 2 0 38 0 5 0 21 0 82 0 20 0
24 Tamil Nadu 2051 8 2501 9 12826 66 6122 0 2804 3 4535 12 2531 5 6919 1
25 Tripura 0 0 0 0 9 0 8 0 6 0 40 0 102 0 62 0
26 Telangana 0 0 0 0 0 0 0 0 704 1 1831 2 4037 4 422 0
27
Uttar
Pradesh
960 8 155 5 342 4 1414 5 200 0 2892 9 15033 42 302 17
28 Uttrakhand 178 0 454 5 110 2 54 0 106 0 1655 1 2146 4 0 0
29West Bengal 805 1 510 0 6456 11 5920 6 3934 4 8516 14 22865 45 571 0
30 A& N Island 25 0 6 0 24 0 67 0 139 0 153 0 92 0 9 0
31 Chandigarh 221 0 73 0 351 2 107 0 13 0 966 1 1246 0 53 0
32 Delhi 6259 8 1131 8 2093 4 5574 6 995 3 15867 60 4431 10 657 1
33 D&N Haveli 46 0 68 0 156 1 190 0 641 1 1154 0 4161 2 443 0
34
Daman &
Diu
0 0 0 0 96 0 61 0 46 0 165 0 89 0 14 0
35 Puduchery 96 0 463 3 3506 5 2215 0 1322 1 771 0 490 2 582 0
Total 28292 110 18860 169 50222 242 75808 193 40571 137 99913 220129166 245 36635 58
Sl.
No.
Affected
States/UTs
2010 2011 2012 2013 2014 2015 2016* 2017*
C D C D C D C D C D C D C D C D
* Provisional till 20th
Aug. 2017

25. 25
Current status of dengue in India
Continue……
(Cecilia et al., 2013)

26. 26
Current status of dengue in India
C- No. of cases D- % Mortality
* Provisional till 20th
Aug. 2017

27. 27
Climatic factors influencing dengue cases in Dhaka city in 2012
(Karim et al., 2012)

28. VECTOR OF DENGUE
• Man and mosquito are reservoirs of infection.
•Dengue is transmitted by the bite of female Aedes mosquito
• In India Ae. aegypti is the main vector in most urban areas; however,
Aedes albopictus is also found as vector in few areas of southern India.
AEDES EGYPTI AEDES ALBOPTICUS

29. 29

30. 30
• The eggs can survive nine months without water.
• It is a day time feeder and can fly up to a limited
distance of 400 meters.
• To get one full blood meal the mosquito has to feed
on several persons, infecting all of them.

31. Ae. aegypti has an average adult survival of fifteen days.
During the rainy season, when survival is longer(around 1month), the risk of virus transmission is greater.
Transovarian transmission (infection carried over to next progeny of mosquitoes through eggs) has made
the control more complicated.

32. 32

33. 1. Mosquitoes transmit
Dengue virus to human dendritic
cells.
2. Virus targets areas
with high WBC counts
(liver, spleen, lymph
nodes, bone marrow,
And glands)
3. Virus enters
WBCs & lymphatic
Tissue
4. Dengue virus enters blood
Circulation.
http://phil.cdc.gov/PHIL_Images/08051999/00004/dengue_phf/sld006.htm
Dengue TransmissionDengue Transmission
3
4
1
2
3

34. 5.The mosquito ingests blood containing the virus.
6.The virus replicates in the mosquito midgut, the ovaries, nerve tissue
and fat body. It then escapes into the body cavity, and later infects the
salivary glands.
7.The virus replicates in the salivary glands and when the mosquito bites
another human, the cycle continues.

35. 35

36. TRANSMISSION CYCLE OF DENGUE
##There is evidence that vertical transmission of dengue virus from infected female mosquitoes to the next
generation occurs through eggs, which is known as transovarian transmission.

37. Transmission

38.  The mosquito becomes infective approximately 7 days after it has bitten
a person carrying the virus.
 The mosquito remains infected for the remainder of its life. The life
span of A aegypti is usually 21 days but ranges from 15 to 65 days.
 The mosquito can lay eggs about 3 times in its lifetime, and about 100
eggs are produced each time.
 The eggs can lie dormant in dry conditions for up to about 9 months,
after which they can hatch if exposed to favourable conditions, i.e. water
and food.

39. PATHOPHYSIOLOGY=IMMUNE RESPONSE
• Primary infection - host develops a life-long protective immunity to the
homologous (same) serotype
• Secondary infection (caused by other 3 serotype) - host shows only partial
and transient protection
• Risk of dengue hemorragic fever

40. PATHOGENESIS 0F PRIMARY INFECTION
Incubation period : 4-7 days (range 3-14)
Primary dengue infection – self limited
May also progress to severe dengue (DHF/DSS) (normally
children, elderly & immunocompromised)
Pathogenesis Of Secondary Infection
“Antibody dependent enhancement mechanism”

41. Non neutralizing
Ab(s)
Mononuclear cells Cytokines,
vasoactive
mediators
procoagulants
DIC
2nd
41
(DIC- Disseminated intravascularcoagulation)

42. 42

43. The Amplifiers
• Man
• Monkey
43

44. The Transmission Cycles
• Enzootic
• Monkey- Aedes- Monkey- Aedes
• Epizootic
• From Epidemic Cycle, DENV crosses overto Non Humans via Bridge Vectors,
Macacasinicain Sri Lanka
• Epidemic
• Human- Aedes- Human- Aedes
44

45. The Environment
• Tropical & Sub- tropical
• Urban, Peri urban; Rural
• Rapid Unplanned uncontrolled urbanization,
• Transportation: human movement and congregation, Airtravel
• Consumerism- Non biodegradable plastic, mismanaged solid waste disposal
• Poorwaterstorage and management
• Seasonal Pattern: Post Monsoon (But Perennial in Gujarat & South India)45

46. Non endemic, Endemic& HyperEndemic
South- East Asia is divided into 3 Categories:
•A: Korea
• B: Bhutan, Nepal
• C: India, Bangladesh, Myanmar, Srilanka, Indonesia, Thailand,
Maldives
46

47. Global Warming
• 2 degree rise in ambient temp-
• Shortens IP- more infected mosquitos to furtherspread DENV
• Enhances the life cycle of Aedes
• Rise in temp- mosquito bites more frequently due to
“dehydration”- furtherspreads DENV 47

48. Distributio n o fAe de s ae g ypti
48

49. Distributio n o fAe de s albo pictus
49

50. CLINICAL PRESENTATION OF DENGUECLINICAL PRESENTATION OF DENGUE
Dengue Virus Infection
Asymptomatic Symptomatic
Undifferentiated
fever
(viral syndrome)
Dengue fever
syndrome
Without
hemorrhage
With unusual
hemorrhage
Dengue
hemorrhagic
fever
(plasma leakage)
No shock Dengue shock
syndrome
Dengue fever Dengue
hemorrhagic Fever
WHO, Geneva, 1997

51. 51
There are actually four dengue clinical syndromes:
1.Undifferentiated fever;
2.Classic dengue fever;
3.Dengue hemorrhagic fever, or DHF; and
4.Dengue shock syndrome, or DSS.
Dengue shock syndrome is actually a severe form of DHF.

52. Dengue FeverDengue Fever
• Older children, adolescents and adults
• Acute (Sudden, sharp) rise in temperature (39°C- 40°C) for 5- 7 days
• Biphasic fever with severe headache, myalgia, arthralgia and bone pains
(break-bone fever), particularly in adults
• Rashes, flushed face, retro-orbital pain on eye movement or eye pressure,
photophobia
• Altered taste sensation, Anorexia, Sore throat, Dragging pain in inguinal region
• Leukopenia and thrombocytopenia- mild
• Occasionally, Haemorrhage such as gastrointestinal bleeding, hyper
menorrhea, massive epistaxis
52

53. Sub
conjunctival
Haemorrhage Petechial
Haemorrhages Pale islands in the red sea
Maculo- papular
Rash
53

54. Dengue Haemorrhagic Fever (DHF)
• Children less than 15 years of age in hyper endemic areas, in association with
repeated dengue infections (secondary dengue infection). Incidence of DHF in adults
is increasing
• Signs and symptoms similar to DF in the early febrile phase.
• Pale islands in red sea
• Positive tourniquet test (TT), petechiae on extremities, easy bruising and/or GI
haemorrhage
• Abnormal haemostasis and plasma leakage are the main pathophysiological
hallmarks of DHF
54

55. TOURNIQUET TEST
 Inflate blood pressure cuff for 5 minutes
 Positive test: 20 or more petechiae per 1 inch2
(6.25 cm2
)
Pan American Health Organization: Dengue and Dengue
Hemorrhagic Fever: Guidelines for Prevention and Control. PAHO:
Washington, D.C., 1994: 12.
Positive tourniquet test

56. Dengue Shock Syndrome (DSS)
• Hypovolemic shock due to plasma leakage
• Pleural effusion, Ascites (plasma leakage to pleural & peritoneal
cavities)
• Hypothermia- Cold clammy skin
• I C Bleeding
• Fulminant hepatic failure
56

57. DSS
• It is of short duration (12- 24 hrs), But can be fatal
• Patient is conscious till stage 4 of the shock (BP not recordable)
• Usually SBP falls late, but pulse pressure (SBP-DBP) deteriorates much
earlier ≤ 20 mmHg
• If prolonged, Shock causes metabolic acidosis and multi organ failure
57

58. Early DiagnosisEarly Diagnosis
58
IHC- Immune Histo Chemistry, , IF- Immuno Fluroscent

59. 59

60.  No specific treatment for Dengue/Severe dengue.
 Early detection and access to proper medical care lowers fatality
rates.
 No hemorrhagic manifestations and patient is well-hydrated: home
treatment
 Hemorrhagic manifestations or hydration borderline: hospitalization
 Warning signs (even without profound shock) or DSS: hospitalize
TreatmentTreatment
 Fluids
 Rest
 Antipyretics
 Monitor blood pressure, hematocrit, platelet count, level of
consciousness

61. PREVENTIONPREVENTION
 Dengue prevention and control solely depends on effective vector control
measures.
 Stay in air-conditioned or well-screened housing.
 It's particularly important to keep mosquitoes out.
 Reschedule out door activities.
 Avoid being outdoors at dawn, dusk and early evening, when more
mosquitoes are out.
 Wear protective clothing. When you go into mosquito-infested areas, wear a
long-sleeved shirt, long pants, socks and shoes.

62. Use mosquito repellent.
Permethrin can be applied to your clothing, shoes, camping gear
and bed netting.
You can also buy clothing made with permethrin already in it.
For your skin, use a repellent containing at least a 10 percent
concentration of DEET (Diethyl toluamide).
Reduce mosquito habitat.
The mosquitoes that carry the dengue virus typically live in and
around houses, breeding in standing water that can collect in
such things as used automobile tyres.
Reduce the breeding habitat to lower mosquito populations.

63. DENGUE VACCINE?
 No licensed vaccine at present
 Effective vaccine must be tetravalent
 Vaccine development for DF and DHF is difficult because any of four different
viruses may cause disease, and because protection against only one or two dengue
viruses could actually increase the risk of more serious disease caused by another
serotype. (Shepard et
al., 2004) A tetravalent live attenuated DEN vaccine trial has been done in Thailand.

64. SummarySummary
Dengue established its roots in India .
 Dengue is an infectious disease caused by a virus.
 You can get it if an infected mosquito bites you.
It is common in warm, wet areas of the world.
 Outbreaks happen in the rainy season.
 Most people with dengue recover within 2 weeks.
However, some dengue infections are severe and
cause bleeding from your nose, gums or under your skin.
Early diagnosis and treatment of dengue is critical
as epidemics of the disease become larger and more frequent.

65.  An estimated 50 to 100 million people are infected with dengue each year in
over 100 countries.
 In severe cases, people infected with dengue may experience severe
bleeding, shock and death.
 Severe dengue is often treated with aggressive emergency treatment, which
includes fluid and electrolyte replacement.
 Prompt treatment can be life saving.
 As the monsoon season favours breeding of Aedes mosquitoes, effective
preventive and control measures need to be taken prior to and with beginning
of monsoon to reduce the occurrence of dengue in the community.

66. THANKTHANK YOUYOU