Presentation made by Md. Kabiul Akhter Ali, VBD Consultant, Uttar Dinajpur, West Bengal

1. DENGUE
MD.KABIUL AKHTER ALI
Vector Borne Disease Consultant
NVBDCP, NRHM
District Heath & Family Welfare Samiti
Uttar Dinajpur

2. Distribution
 Endemic in more than
100 tropical and
subtropical countries
 Pandemic began in South
East Asia after WW II
with subsequent global
spread
 Several epidemics since
1980s
 Distribution is comparable
to malaria

3. Epidemiology
In India first outbreak of dengue was recorded in
1812
A double peak hemorrhagic fever epidemic
occurred in India for the first time in Calcutta
between July 1963 & March 1964
In New Delhi, outbreaks of dengue fever reported
in 1967,1970,1982, &1996

4. Burden of disease in S.E. Asia
CATEGORY-A
(INDONESIA,MYANMAR & THAILAND)
CATEGORY-B
(INDIA,BANGALADESH,MALDIVES & SRILANKA)
CATEGORY-C
(BHUTAN, NEPAL)
CTEGORY-D
(DPR KOREA)

5. Dengue Endemic Areas
(1996 to 2010 = 29 States/UTs)
Risk factors:
•Construction
activities
• Water storage
practice
•Population
movement
•Heavy rainfall
•Vector abundance

7. Dengue Fever
 Dengue endemic in 29 States/UTs, upsurge observed in 2010
 States reported higher numbers of cases in 2010 (as on Dec 31)
 Dengue being reported from newer areas (Assam, Meghalaya,
Chhattisgarh, Jharkhand, Manipur, Nagaland, Uttarakhand ,A&N
Islands)

10. 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

11. Dengue clinical syndrome
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.

12. CLASSIS DENGUE
 Acute febrile illness with headache, retro-orbital
pain, myalgia, arthralgia
 “Break-bone fever”
 High fever 5-7 days
 Second fever for 1-2 days in 5% patients
 Followed by marked fatigue days to weeks
 Classic dengue 15-60% of infections
 Nausea, vomiting, diarrhea (30%)
 Macular or maculopapular rash (50%)
 Respiratory symptoms: cough, sore throat (30%)

13. SIGNS & SYMPTOMS OF DENGUE FEVER
•Abrupt onset of high fever
•Severe frontal headache
•Pain behind the eyes which worsens with eye movement
•Muscle and joint pains
•Loss of sense of taste and appetite
•Measles-like rash over chest and upper limbs
•Nausea and vomiting

14. Dengue Hemorrhagic Fever
WHO classification of DHF Usually occurs in secondary
infections after actively or passively
 Thrombocytopenia (platelet count (maternal) acquired immunity to a
<100,000) different viral serotype
Only 2-4% of secondary infections
 Fever 2-7 days result in severe disease
 Hemorrhagic manifestations with a Mortality is 10-20% if untreated,
positive tourniquet test but decreases to <1% if adequately
 Hemoconcentration or evidence of treated
plasma leakage
Plasma leakage may progress to
dengue shock syndrome

15. SIGNS & SYMPTOMS OF DENGUE
HAEMORRHAGIC FEVER AND SHOCK SYNDROM
• Symptoms similar to dengue fever
•Severe continuous stomach pains
•Skin becomes pale, cold or clammy
•Bleeding from nose, mouth & gums and skin rashes
•Frequent vomiting with or without blood
•Sleepiness and restlessness
•Patient feels thirsty and mouth becomes dry
•Rapid weak pulse
•Difficulty in breathing

16. AGENT FACTORS
•The dengue viruses are the members of the genus
flavivirus. These small (50nm)viruses contain single stranded
RNA.
•There are four virus serotypes, which are designated as
DEN-1, DEN-2, DEN-3 and DEN-4.
•Although all four serotypes are antigenicaly similar, they
are different enough to elicit cross-protection only for a few
months after infection by any one of them. Infection with
any one serotype confers lifelong immunity to the virus
serotype.
•Man and mosquito are reservoirs of infection. Transovarian
transmission (infection carried over to next progeny of
mosquitoes through eggs) has made the control more
complicated.
•At present DEN1 and DEN2 serotypes are widespread in
India

17. VECTOR OF DENGUE
• Dengue is transmitted by the bite of female Aedes mosquito
• In India Ae. aegypti is the main vector in most urban areas; however,
Ae albopictus is also found as vector in few areas of southern India.
• Female Aedes mosquito deposits eggs singly on damp surfaces just
above the water line. Under optimal conditions the life cycle of aquatic
stage of Ae. Aegypti (the time taken from hatching to adult
emergence) can be as short as seven days
• The eggs can survive one year without water. At low temperature,
however, it may take several weeks to emerge. Ae. aegypti has an
average adult survival of fifteen days. During the rainy season, when
survival is longer, the risk of virus transmission is greater. 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.

18. 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.

19. TRANSMISSION CYCLE OF DENGUE
1.The virus is inoculated into humans with the
mosquito saliva.
2.The virus localizes and replicates in various target
organs, for example, local lymph nodes and the
liver.
3.The virus is then released from these tissues and
spreads through the blood to infect white blood
cells and other lymphatic tissues.
4.The virus is then released from these tissues and
circulates in the blood.
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.

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

21. LABORATORY DIAGNOSIS OF DENGUE
Haemagglutination inhibition (HI) test
Compliment Fixation Test (CFT)
Neutralization test (NT)
IgM-capture Enzyme-Linked Immunosorbent
Assay (MAC-ELISA) ndvbcp recommended
IgG-ELISA
Rapid Diagnostic tests (NS 1)

22. Management of Dengue Fever (DF)
• No specific therapy, management of Dengue fever is symptomatic and
supportive
i. Bed rest is advisable during the acute phase.
ii. Use cold sponging to keep temperature below 39o C.
iii. Antipyretics may be used to lower the body temperature. Aspirin/NSAID like
Ibuprofen etc should be avoided since it may cause gastritis, vomiting, acidosis
and platelet disfunction.
Paracetamol is preferable in the doses as follows:
1-2 years: 60 -120 mg/doses 3-6 years: 120 mg/dose 7-12 years: 240 mg/dose
Adult : 500mg/dose
In children the dose is calculated as per 10mg/KG Body Weight per dose
which can be repeated at the interval of 6hrs
iv. Oral fluid and electrolyte therapy are recommended for patients with
excessive sweating or vomiting.
v. Patients should be monitored in DHF endemic area until they become
afebrile for one day without the use of antipyretics and after platelet and
haematocrit determinations are stable, platelet count is >50,000/ cumm.

23. Vaccination
 No current dengue vaccine
 Estimated availability in 5-10 years
 Vaccine development is problematic as the vaccine
must provide immunity to all 4 serotypes
 Lack of dengue animal model
 Live attenuated tetravalent vaccines under phase 2
trials
 New approaches include infectious clone DNA and
naked DNA vaccines

24. Prevention
Personal:
 clothing to reduce exposed skin
 insect repellent especially in early morning, late
afternoon. Bed netting important
 mosquito repellants(pyrethroid based)
 coils, sanitation measures
Environmental:
 reduced vector breeding sites
 solid waste management
 public education
 empty water containers and cut weed/tall grass

25. Prevention
Biological:
 Target larval stage of Aedes in large water storage
containers
 Larvivorous fish (Gambusia), endotoxin producing
bacteria (Bacillus), copepod crustaceans (mesocyclops)
Chemical:
Thermal fogging-malathion,pyrethrum
 Insecticide treatment of water containers
 Space spraying (thermal fogs)
 Indoor space spraying(2% pyrethrum),
organophosphorus compounds

26. Social Issues
Although the goal of disease control is to prevent epidemic
transmission, if an epidemic does occur, ways to minimize its
impact include:
•Teaching the medical community how to diagnose and manage
dengue and dengue hemorrhagic fever (DHF), so they are better
prepared to effectively manage and treat large numbers of cases.
Mortality from DHF will thus be minimized.
•Implementing an emergency contingency plan to anticipate the
logistical issues of hospitalizing large numbers of patients and to
outline measures for community-wide vector control activities.
Such plans should be prepared with the participation of all parties
and agencies involved, and should be ready for implementation
prior to the emergence of an epidemic.
•Educating the general public to encourage and enable them to
carry out vector control in their homes and neighborhoods.

32. Public Health
 Major and escalating global public health problem
 Global demographic changes: urbanization and population
growth with substandard housing, water, and waster
management systems
 Deteriorating public health infrastructure with limited
resources resulting in “crisis management” not prevention
 Increased travel
 Lack of effective mosquito control

33. Initiatives
 Strategic action plan
 Guidelines on clinical management
 13 centers identified for Apex Referral laboratories for
diagnosis/treatment and surveillance
ICMR Virus Unit, Kolkata.
 137 sentinel surveillance hospitals amongst them in west
bengal
 1.Burdwan Medical College Hospital.
 2. School of Tropical Medicine, Calcutta
 NIV Pune to supply ELISA kits
 Contingency grant made available
 IEC/BCC

34. THANK YOU