Dengue is a viral disease transmitted by Aedes mosquitoes that is a major public health problem globally. It is endemic in over 100 countries and the distribution is comparable to malaria. There are four serotypes of the dengue virus. Dengue fever presents as a severe flu-like illness, while dengue hemorrhagic fever is a more severe form that can be fatal if untreated. Management involves treatment of symptoms, fluid replacement, monitoring for signs of plasma leakage, and blood transfusion if needed. Prevention relies on reducing mosquito breeding sites and personal protection against bites. Currently there is no vaccine for dengue.

1. DENGUE

2. Learning Objectives
•Epidemiological Triad
•Classification
•Management

3. 1.Introduction
•ARBO

4. 2. PROBLEM STATEMENT
•GLOBAL
•SEAR
•INDIA

5. Distribution


Endemic in more than
141 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

6. 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

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

8. Dengue Endemic Areas
(1996 to 2015 =25States/UTs)
Riskfactors:
•Construction
activities
• Water storage
practice
•Population
movement
•Heavy rainfall
•Vector abundance

10. Dengue Fever
 Dengue endemic in 28+ 8 States/UTs, upsurge observed in
2010 & till date 2023
 States reported higher numbers of casesin 2010 (ason Dec31)
 Dengue being reported from newer areas (Assam, Meghalaya,
Chhattisgarh, Jharkhand, Manipur, Nagaland, Uttarakhand ,A&N
Islands)

12. 3.Epidemiological triad

13. A. 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
DENV-1,DENV-2,DENV-3and DENV-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

14. B. VECTOR OFDENGUE
• Dengue is transmitted by the bite of femaleAedesmosquito
• In India Ae.aegypti is the main vector in most urban areas;however,
Aealbopictus is also found asvector in few areas of southernIndia.
•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.

15. Fewcommon andfavoured
breeding places/sites of
Ae. aegypti

16. TRANSMISSION CYCLEOFDENGUE
##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.

17. 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.
TRANSMISSION CYCLEOFDENGUE
1.The virus is inoculated into humans with the
mosquito saliva.

18. C. HOST FACTORS
HIGH RISK PERSONS:
1.Infants;
2.obesity;
3. pregnancy;
4. peptic ulcer disease;
5. women who are in menstruation or have abnormal
bleeding;
6. haemolytic disease such as G—6PD, thalassaemia and
other haemoglobinopathies;
7. congenital heart disease;
8. chronic diseases such as diabetes mellitus,
hypertension, asthma, ischaemic heart disease, chronic
renal failure, liver cirrhosis;
9. patients on steroid or NSAID treatment.

19. 4.Clinical features

20. WHAT IS DENGUE?
•Dengueis aviral disease
•It is transmitted by the infective bite of femaleAedesAegypti mosquito
•Man develops disease after 5-6 daysof being bittenby an infective
mosquito
•It occurs in two forms:Dengue Fever and DengueHaemorrhagic
Fever(DHF)
•DengueFever is asevere, flu-like illness (Influenza)
•DengueHaemorrhagic Fever (DHF)is amore severe form of
disease,which may causedeath
•Person suspected of having dengue fever or DHFmust seeadoctor atonce

21. 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.
Dengue clinical syndrome

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

23. SIGNS & SYMPTOMS OFDENGUE FEVER
• Abrupt onset of highfever
• Severefrontal headache
• Pain behind the eyeswhich worsens with eyemovement
• Muscle and joint pains
•Loss of senseof taste andappetite
• Measles-like rash over chest and upperlimbs
• Nauseaand vomiting

24. Dengue HemorrhagicFever
WHOclassification of DHF
 Thrombocytopenia (platelet count
<100,000)
 Fever2-7 days
 Hemorrhagic manifestations with a
positive tourniquet test
 Hemoconcentration or evidenceof
plasmaleakage
treated
Usually occurs in secondary
infections after actively or passively
(maternal) acquired immunity to a
different viral serotype
Only 2-4% of secondary infections
result in severedisease
Mortality is 10-20% if untreated,
but decreasesto <1%ifadequately
Plasma leakage may progress to
dengue shocksyndrome

25. SIGNS & SYMPTOMS OFDENGUE
HAEMORRHAGIC FEVER AND SHOCKSYNDROM
• Symptoms similar to denguefever
• Severecontinuous stomach pains
• Skinbecomes pale, cold or clammy
• Bleeding from nose, mouth & gums and skinrashes
• Frequent vomiting with or without blood
• Sleepinessand restlessness
• Patient feels thirsty and mouth becomesdry
• Rapidweak pulse

26. LABORATORY DIAGNOSIS OFDENGUE
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)

27. 5. 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.

28. Crystalloids-
Indication of Blood Transfusion:
PCV:

29. Discharge criteria
1. Absence of fever for at least 24 hours without
the use of anti-pyretic drugs.
2. Return of appetite.
3. Visible clinical improvement.
4. Good urine output.
5. Minimum of 2-3 days after recovery from
shock.
6. No respiratory distress from pleural effusion or
ascites.
7. Platelet count > 50,000/cu.mm.

30. Vaccination





No current dengue vaccine
Estimated availability in 5-10years
Vaccine development is problematic asthe vaccine
must provide immunity to all4 serotypes
Lackof dengue animal model
Live attenuated tetravalent vaccines under phase2
trials
 New approaches include infectious clone DNAand
naked DNAvaccines

31. Prevention
Personal:




clothing to reduce exposedskin
insect repellent especially in early morning,late
afternoon. Bednetting important
mosquito repellants(pyrethroid based)
coils, sanitation measures
Environmental:
 reduced vector breedingsites
 solid wastemanagement
 public education
 empty water containers and cut weed/tallgrass

32. Prevention
Biological:


Target larval stage of Aedesin large waterstorage
containers
Larvivorous fish (Gambusia), endotoxin producing
bacteria (Bacillus), copepod crustaceans (mesocyclops)
Chemical:
Thermal fogging-malathion,pyrethrum
 Insecticide treatment of watercontainers
 Spacespraying (thermal fogs)
 Indoor spacespraying(2% pyrethrum),
organophosphorus compounds

33. 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.
Social Issues

36. Public Health
 Major and escalating global public healthproblem
 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” notprevention
 Increasedtravel
 Lackof effective mosquito control

37. THANK YOU