Dengue=total uptodate

Introduction
Epidemiology
Vector
Viral Morphology
Mode of Transmission
Pathogenesis
Immune Response
Clinical Manifestations
Complications
Lab Diagnosis
Control and Prevention
OUTLINE

Infected Aedes mosquito
Deng
ue
Dengue

WHAT IS DENGUE
?=INTRODUCTION
•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 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

Hemorrhagic Fever
Viruses: Taxonomy
Arenaviridae
¨ Ebola HF
(Ebola Virus
Marburg HF
(Marburg
Virus
Rift Valley
Fever ( RVF
Virus )
Crimean-Congo
HF (CCHF
Virus)
Hantavirus
Genus
HFRS (rodents
urine)
Argentine HF
 ( Junin Virus)
Bolivian HF
(Machupo
Virus)
Venezuelan
HF (Guanarito
Virus)
Brazilian HF
(Sabia Virus)
 Lassa Fever
Yellow Fever
West Nile
Fever
Dengue HF
¨Kyasanur Forest
Disease (KFD Virus)
¨Omsk HF( OHF
Virus)
¨ALKHUMRA
¨Mosquito-
Borne:
¨Tick-
Borne:
Bunyaviridae Filoviridae Flaviviridae

 1. Dr Benjamin Rush a professor of chemistry and
medical theory at the UPEN, during the Philadelphia
epidemic 1779 -1780 , first described the dramatic
symptoms of dengue as break bone fever.
 2.A small percentage of persons who have previously
been infected by one dengue serotype develop
bleeding and endothelial leak up on infection with
another dengue serotype. This syndrome is termed
dengue hemorrhagic fever (DHF). Also been termed
dengue vasculopathy.
 3. Vascular leakage in these patients results in
hemoconcentration and serious effusions and can
lead to circulatory collapse.

Present in most tropical and sub-tropical (less
humid) climates
Africa
Southeast Asia and China
India
Middle East
Caribbean and Central and South America
Australia and the South and Central Pacific
Some parts of the U.S., namely Texas and
Hawaii
WHERE IS DENGUE FOUND

 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.
 Increased worldwide distribution of disease seen
after World War II

DENGUE VIRUS
 Dengue fever is an acute infectious viral disease, also
known as breakbone fever.
 It is a arthropod-borne (arboviral) illness in human . It
is caused by infection with 1 of the 4 serotypes of
dengue virus (DENV1,2,3,4), which is a Flavivirus(a
genus of single-stranded nonsegmented RNA
viruses).
 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
.
 Several serotypes can be in circulation during an
epidemic.

DENGUE VIRUS= SMALL (50NM)VIRUSES
Electron Micrograms

16
DEN 1 DEN 2 DEN 3 DEN 4
Caused by any one of
four closely related
dengue viruses

17
.At present DEN1 and DEN2 serotypes are widespread in
India

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

23
1. Is spread by the vector aedes aegypti
2. Has an incubation period of 2-3 week
3. Has an incubation period of 3 to 14 days ,
normally 4 to 7 days
4. Is caused by a flavivirus
5. Is more likely to cause haemorrhage in
patients previously infected by a dengue
virus
6. Characterized by Fever , muscle and join
pain
TRUE OR FALSE

25
• Female Aedes mosquito deposits eggs singly on damp surfaces
just above the water line
• The eggs can survive one year without water. At low
temperature, however, it may take several weeks to emerge.
• 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.

. 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.

• 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

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

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.

The transmission cycle of dengue virus by the
mosquito Aedes aegypti begins with a dengue-
infected person.
This person will have virus circulating in the
blood—a viremia that lasts for about five days.
During the viremic period, an uninfected female
Aedes aegypti mosquito bites the person and
ingests blood that contains dengue virus.
Although there is some evidence of transovarial
transmission of dengue virus in Aedes aegypti,
LIFECYCLEIN1 PERSON

1.The virus is inoculated into humans with the
mosquito saliva. Once dengue enters one’s body, it
enters the dendritic cells (specialized cells found in
most tissues)
2.The virus localizes and replicates in various
target organs, . Dengue targets areas with high WBC
counts(liver, spleen, lymph nodes, bone marrow, and
glands)
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.

LIFE CYCLE IN MOSQUITO
1. Then, within the mosquito, the virus
replicates during an extrinsic incubation
period of eight to twelve days.
2. The mosquito then bites a susceptible
person and transmits the virus to him or
her, as well as to every other susceptible
person the mosquito bites for the rest of its
lifetime
3. The mosquito ingests blood containing the
virus.
4. The virus replicates in the mosquito

 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.

 The mosquito then bites a susceptible person and
transmits the virus .
 The virus then replicates in the second person and
produces symptoms.
 The symptoms begin to appear an average of four to
seven days after the mosquito bite—this is the
intrinsic incubation period, within humans.
 It can range from 3 to 14 days (average 4-7 days)
 The viremia begins slightly before the onset of
symptoms.
 Symptoms caused by dengue infection may last three
to 10 days, with an average of five days,
 after the onset of symptoms—so the illness persists
several days after the viremia has ended.
LIFECYCLEIN 2 PERSON

TRANSMISSION
Mosquito feeds viremic human ---- 8 to 14 days --- its
becomes infective
Virus multiplies in the system of vector
Virus is injected into human by mosquito
After 3-14 days (Incubation period) host develops
fever , and other symptoms

43
While viral replication takes place in target
dendritic cells. Infection of target cells, primarily
those of the reticuloendothelial system, such as
dendritic cells, hepatocytes, and endothelial
cells

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

PATHOGENESIS 0F PRIMARY
INFECTION
Incubation period : 4-7 days (range 3-14)
Primary Dengue Infection – Self Limited
May also progress to severe dengue (DHF/DS
(normally children, elderly &
immunocompromised)
Pathogenesis Of Secondary Infection
Infection by
virus of
another
serotype
Production
of non
neutralizing
antibodies
Facilitate
entry of
virus to
monocytes
through Fc
Receptor
“Antibody dependent enhancement
mechanism”

47
1. After the Primary Infection , the host develops a Life-long
protective immunity to the homologous serotype
2. Secondary Infection has less chances of Dengue
Hemorrhagic Fever
3. Primary Dengue Infection is usually not self limited
4. Production of neutralizing antibodies is the key concept in
Secondary Infection
5. Non Neutralizing antibodies Facilitate the entry of virus into
monocytes through Fc Receptor and enables the virus to
grow in the host cell (monocyte)
6. In secondary infection the immune response is destructive
rather then protective – Its due to “Antibody dependent
enhancement mechanism”
TRUE OR FALSE

50
 This result in the production of immune mediators
that serve to shape the quantity, type, and duration
of cellular and humoral immune response to both
the initial and subsequent virus infections.
 Fever typically begins on the third day of illness
and persists 5-7 days, abating with the cessation
of viremia. Fever may reach 41C°.
 Occasionally, and more frequently in children, the
fever abates for a day and recurs, a pattern that is
termed a saddleback fever; however, this pattern is
more commonly seen in dengue hemorrhagic
fever.

ANTIBODY DEPENDANT ENHANCEMENT
55

COMPLIMENT ACTIVATION MECHANISM
63

CLINICAL MANIFESTATIONS OF DENGUE AND
DENGUE HEMORRHAGIC FEVER

65
A. Fever
B. Hemorrhagic manifestations
C. Muscle and Join Pain
D. Low platelet count (100,000/mm 3 or less
E. Elevated hematocrit ( >20% then normal)
F. Elevated Hematocrit ( > 50% then
baseline)
TRUE OR FALSE
REGARDING THE WHO CRITERIA FOR D H F

66
Hematocrit (Hct) Percentage of the volume of
whole blood that is made up of red blood cells
Hct MORE THEN 50 PERCENT THEN baseline
means first day of admittance
OR MORE THEN 20 percent then normal
value for men or women
Normal Male Hct 40.7 to 50.3%
Normal Female Hct: 36.1 to 44.3%

DENGUE CLINICAL SYNDROMES
Undifferentiated fever
Classic dengue fever
Dengue hemorrhagic fever
Dengue shock syndrome( is actually
a severe form of DHF.)

UNDIFFERENTIATED
FEVER
May be the most common
manifestation of dengue
Prospective study found that 87% of
students infected were either
asymptomatic or only mildly
symptomatic
Other prospective studies including
all age- groups also demonstrate
silent transmission

CLINICAL CHARACTERISTICS
OF DENGUE FEVER
Fever
Headache
Muscle and joint pain
Nausea/vomiting
Rash
Hemorrhagic

CLASSIC 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%)

DF (FEBRILE PHASE II)










Symptoms – Dengue Fever
Positive tourniquet test
Goal of the test :-
 To asses fragility of capillary walls
 To identify thrombocytopenia
 In DHF grade 1, a positive
tourniquet test serves as the only
indicator of haemorrhagic tendency
• 20 or more
petechiae
per 1
square
inch. (MOH
MALAYSIA
2014)

HOW TO DO ?
1. Take the patient's blood pressure and
record it, for example, 100/70.
2. Inflate the cuff to a point midway
between SBP and DBP and maintain for
5 minutes. (100 + 70) ÷ 2 = 85 mm Hg
3. Reduce the pressure and wait 2
minutes.
4. Count petechiae below antecubital
fossa. See image at right.
5. A positive test is 20 or more petechiae
per 1 square inch.

MAIN PROBLEMS
Dehydration
Febrile seizures
Neurological
disturbances

RASH
http://www.itg.be/itg/DistanceLearning/LectureNotesVandenEndenE/imagehtml/ppages/CD_1038_061c.htm. Used with permission

SUBCUTANEOUS
HEMORRHAGE IN DHF
http://www.orble.com/aia/

CRITICAL PHASE I
Occurs at time of defervescence
Around days 3-7 of illness
Temperature drops to 37.5-38.0°C or below
Lasts 24-48 hours
Systemic vascular leak syndrome
Increasing hematocrit
Hypoproteinemia
Pleural effusions
Ascites

HCT=IMPORTANCE
83
The haematocrit(hct) also known as
packed cell volume (PCV) is the volume
percentage (%) of red blood cells in
blood. When the plasma level becoming
lower , the blood is saturated with RBC ,
thus haematocrit value increases
So Measuring the HCT is the most
suitable way to detect haemorrhage.
Platelet level will be low in even non

CRITICAL PHASE II
Progressive leukopenia
Rapid thrombocytopenia
Degree of plasma leakage varies
Increase in Hct a good barometer
Shock
If is to occur, preceded by warning signs
Follow fluid management closely
CXR, US

MAIN PROBLEMS
Shock from plasma leakage
Can have fluid overload
secondary to overhydration
Organ Impairment
Severe hemorrhage

RECOVERY PHASE
After critical phase, 48-72 hours of reabsorption of
extravascular fluid
Well-being, appetite improves
Bradycardia common
Hemodynamic status improves
GI symptoms abate
Blood counts normalize (RBC>WBC>Plt)
Diuresis occurs
Prolonged convalescence

MAIN PROBLEMS
Hypervolemia
Due to overly aggressive
fluid resuscitation

WHO: Guidelines for diagnosis, treatment, prevention and control Geneva 2009

SEVERE DENGUE I
Severe plasma leakage
Shock (DSS)
Serosal fluid accumulation with respiratory
distress
Severe bleeding
Clinically evident
Multi-organ involvement
Liver: AST/ALT >1000
CNS: Impaired consciousness, seizures,
encephalopathy
CV and other

SEVERE DENGUE II
Clinical signs
Tachycardia, peripheral vasoconstriction
DBP rises towards SBP (narrowed pulse
pressure, ≤ 20 mmHg)
Patient may be conscious and lucid
Poor perfusion
Cold, clammy extremities
Rapid, weak pulse
Mental status changes
Serosal fluid accumulation with respiratory
distress

SEVERE DENGUE III
Severe bleeding
Clinically evident
Multi-organ involvement
Liver: AST/ALT >1000
CNS: Impaired consciousness,
seizures, encephalopathy
CV (cardiomyopathy) and other
Coagulopathy

CONSIDER SEVERE DENGUE
Patient is coming from an area of high dengue risk, has had 2-7
days of fever, plus any of the following:
There is evidence of plasma leakage, such as:
 high or progressively rising hematocrit;
 pleural effusions or ascites;
 circulatory compromise or shock (tachycardia, cold and clammy extremities,
 capillary refill time greater than three seconds, weak or undetectable pulse,
 narrow pulse pressure or, in late shock, unrecordable blood pressure).
There is significant bleeding.
There is an altered level of consciousness (lethargy or
restlessness, coma, convulsions).
There is severe gastrointestinal involvement (persistent
vomiting, increasing or intense abdominal pain, jaundice).
There is severe organ impairment (acute liver failure, acute
renal failure, encephalopathy or encephalitis, or other
unusual manifestations, cardiomyopathy) or other unusual
manifestations.

SIGNS AND SYMPTOMS OF
ENCEPHALITIS/ENCEPHALOPATHY
ASSOCIATED WITH ACUTE DENGUE
INFECTION
Decreased level of consciousness:
lethargy, confusion, coma
Seizures
Nuchal rigidity
Paresis

HEMORRHAGIC MANIFESTATIONS
OF DENGUE
Skin : petechiae, purpura,
ecchymoses
Gingival bleeding
Nasal bleeding
Gastro-intestinal bleeding:
hematemesis, melena
Hematuria
Increased menstrual flow

CLINICAL CASE DEFINITION FOR
1. Fever, or recent history of acute fever
2. Hemorrhagic manifestations(with a positive
TT)
3. Low platelet count (100,000/mm3 or less)
4. Objective evidence of “leaky capillaries” :
elevated hematocrit (20% or more over
baseline)
low albumin
WHO=4 Necessary Criteria:

FOUR GRADES OF DHF
Grade 1
Fever and nonspecific constitutional symptoms
Positive tourniquet test is only hemorrhagic
manifestation
Grade 2
Grade 1 manifestations + spontaneous bleeding
Grade 3
Signs of circulatory failure (rapid/weak pulse, narrow
pulse pressure, hypotension, cold/clammy skin)
Grade 4
Profound shock (undetectable pulse and BP)

DANGER SIGNS IN
Abdominal pain - intense and
sustained
Persistent vomiting
Abrupt change from fever to
hypothermia, with sweating and
prostration
Restlessness or somnolence

WARNING SINGS OF DENGUE
 Raised HCT, with rapid fall in platelet
 Fever to hypothermia
 Mucosal Bleed
 Liver Enlargement
Normal Male Hct 40.7 to 50.3%
Normal Female Hct: 36.1 to 44.3%
The normal number of platelets in the blood is
150,000 to 400,000 platelets per microliter (mcL).

Warning Signs for Dengue
Shock
When Patients Develop
DSS:
• 3 to 6 days after onset of
symptoms
Initial Warning
Signals:
• Disappearance of
fever
• Drop in platelets
• Increase in
hematocrit
Alarm Signals:
• Severe abdominal pain
• Prolonged vomiting
• Abrupt change from
fever
to hypothermia
• Change in level of
consciousness
(irritability
or somnolence)
Four Criteria for DHF:
• Fever
• Hemorrhagic manifestations
• Excessive capillary
permeability
•  100,000/mm3 platelets

UNUSUAL PRESENTATIONS
OF SEVERE DENGUE FEVER
Encephalopathy
Hepatic damage
Cardiomyopathy
Severe gastrointestinal
hemorrhage

RISK FACTORS FOR DHF/DSS
Pre-existing immunity from previous infection (heterogenous
subtype)
Diabetics, asthmatics, other chronic diseases
DENV type
 DENV-1,3 > 2,4
Increased time between infections
Under age 15
 Increased capillary fragility
HLA type and race*
 Caucasian>AA
 HLA Class-1 alleles
Female sex
AB blood group
Promotor variant of DC-SIGN receptor
Single-nucleotide polymorphism in TNF gene
*De la C Sierra B, Kouri G, Guzman MG. Arch. Virol., 2007, 152(3) 533-42. Epub 2006 Nov. 16.

112
 If left untreated, dengue hemorrhagic fever most
likely progresses to dengue shock syndrome.
Common symptoms in impending shock include
abdominal pain, vomiting, and restlessness.
Patients also may have symptoms related to
circulatory failure.
https://en.wikipedia.org/wiki/Dengue_fever

113
A. Fever
B. Hemorrhagic manifestations
C. Muscle and Join Pain
D. Low platelet count (100,000/mm 3 or less
E. Elevated hematocrit ( >20% then normal)
F. Elevated Hematocrit ( > 50% then
baseline)
TRUE OR FALSE
REGARDING THE WHO CRITERIA FOR D H F

DIAGNOSIS
History Clinical Lab
History tells us the endemic area, previous dengue infection and
etc
Clinical diagnosis are all the symptoms. We can make only
provisional diagnosis

LABORATORY TESTS IN DENGUE FEVER
Routine Clinical laboratory tests
CBC;WBC=Leukopenia,Lymphocytosis,
 platelets=Thrombocytopenia
Hematocrit=Haemoconcentration(Hct. inc. >20%)*
(Plasma leakge)
Albumin=Hypoalbumenia(Plasma leakge)
Liver function tests=Elevated SGOT &SGPT
Urine--check for microscopic hematuria
Peak proteinuria**
0.56 v. 0.08 g/d (P<0.001), onset 1 day after defervescence (-2
to 3 days)

118
Direct – detection of viral components :
• Virus isolation & Culture
• RT- PCR(reverse transcriptase-pcr)
• NS-1 AG det by (ELISA / lateral flow rapid)
Indirect by serology
Plaque reduction neutralisation test(PRNT)
Haemagglutination inhibition test
Antibody detection=IgM elisa & IgG elisa
Dengue Rapid Tests
Complement Fixation Tests
Dot Blot Immuno Assay
DENGUE-SPECIFIC TESTS

121
 Its confirmatory , identifies serotype .
 Needs acute serum sample(first 5 days)
 Does not differentiate between primary and secondary
 Can be done only at research lab
Viral cell culture :

 Detection of virus by culture is obviously the
definitive diagnostic test.
 By the time a person infected with Dengue develops
fever, the infection is widely disseminated.
 The virus is found in serum or plasma, in circulating
blood cells and in selected tissues, especially those of
the immune system, for approx. 2-7 days, roughly
corresponding to the period of fever.
 Detection of dengue RNA using specific oligonucleotide
primers, reverse transcriptase and thermostable
polymerase are Faster and are applied in many
Laboratories.
VIRUS ISOLATION

Drawbacks and limitations of Viral isolation
 The period of illness when the dengue virus can
be successfully detected is brief
 Within a day or 2 after subsidence of fever,
the rising level of antibody interfere with virus
culture
 Dengue virus is heat-labile and special
precautions must be taken against the thermal
inactivation of specimens.
 Laboratories equipped and staffed to culture
viruses are expensive to develop and maintain.
LABORATORY DIAGNOSIS OF DENGUE FEVER: VIRUS
DETECTION

LABORATORY DIAGNOSIS OF DENGUE FEVER: VIRUS
DETECTION

LABORATORY DIAGNOSIS OF DENGUE
FEVER: VIRUS DETECTION
Inoculation into mosquitos
 Most sensitive dengue viral culture technique
 Serum, Plasma, CSF, Pleural fluid, Peripheral blood
leucocytes & tissue homogenates can be used
 Toxorhynchites mosquitos generally used
 They are not hematophagus and their large size facilitates
inoculation
 Infection is detected by Immunofluorescence of a tissue
smear prepared from the crushed head of the mosquito (Head
Squash)
 High sensitive culture requires 5-20 mosquitos per specimen
 adult male Aedes aegypti & Ae. Albopictus can also be used.

Inoculation into mosquitos
Toxorhynchites Ae. aegypti & Ae. Albopictus
 Large, easy to inoculate Small, difficult to inoculate
 Raising is labour intensive,
as the larvae are carnivorous
& needs a second mosquito
species larvae as food source
Easier to maintain
 Non Hematophagus, hence
safe to handle
Female spp can’t be used due
to ability to act as vector

Inoculation into mosquito cell lines
 C6/36 and AP-61 cell lines can be used
 Less sensitive than direct inoculation into live
mosquitoes
 Cell cultures to be screened for specific
evidence of infection by an immunoassay as the
cytopathic effects might be absent in many
dengue virus isolates
 As mosquito cell lines are propagable in
ambient tropical temperatures (25-34° C), it is
easier to maintain and practice

Inoculation into vertebratecell lines
 VERO and LLC-MK2 cell lines can be used
 Least sensitive than other direct inoculation methods
All cultures are examined using serotype-specific
anti-Dengue monoclonal Abs tagged to a second
labelled Ab.
Positive control: Dengue-complex-reactibe MAb
 Intracerebral inoculation into newborn mice is
also tried in certain laboratories : but have
proven to be very less sensitive

Sample:
 Peripheral Blood Leukocyte
 Autopsy Lung, Liver specimen
 Less commonly: Autopsy Thymus, Spleen, Lymph
node, Bone marrow
Mainly for epidemiological purpose and confirmation
of epidemic / outbreak.
Immunohistochemistry examined using serotype-
specific anti-Dengue monoclonal Abs tagged to a
second labelled Ab.
LABORATORY DIAGNOSIS OF
DENGUE FEVER: ANTIGEN DETECTION
IN FIXED TISSUE

REAL-TIME PCR
133
 Useful for first five days of symptoms
 80-90% sens, >90% specificity
 Better sensitivity when combined with serology
follow
 FDA approved

NUCLEIC ACID AMPLIFICATION
(NAAT)
RT-PCR, Real Time RT-PCR, NASBA
Better sensitivity (80-100%) than isolation
Standardization? False positive results? Expensive
(expertise and equipment)
Cant differentiate between 1º and 2º infections
Do not differentiate between the different
serotypes
Not as sensitive as isolation or RNA detection

1. Non Structural Protein (NS1 antigen)
Test- to detect NS1 antigen
2. Serological Test using ELISA – To
Detect Antibody( Ig M and Ig G )
Antigen Detection
 NS1, E/M antigens
 Antigen capture ELISA,
 lateral flow antigen detection,
 NS1 IgM, IgG responses
Most widely used Diagnostic
Test

1. NS1 ANTIGEN
(NON STRUCTURAL PROTEIN) TEST
 Latest diagnostic tool for diagnosing dengue
 Useful in the diagnosing in the early phase
 Sensitivity in first 5 days – febrile phase(3 to 4 of
illness) Some times even from second day of illness
 But It is not useful after 5 days of illness .
 Criteria for primary infection
Postive NS1 antigen( >90% for primary infection)
 Criteria for secondary infection(60-80% for secondary
infection.)
Usually Negative NS1 antigen rarely
Can be Positive as well.

139
NS- 1 Ag :
 Structural protein secreted by all
flaviviridae
 Detectable upto 10 days after onset
of illness
 Disappear once seroconversion has
occurred
 ELISA/rapid test lat flow serology NS-
1 specific IgM, IgG
 Many commercial rapid test :15mn
 Not FDA approved
 Cross reactivity due to other
flaviviridae.
 Lateral flow test : IgG, IgM, NS-1 Ag

CURRENT RAPID DIAGNOSTIC
TECHNOLOGIES
Agglutination
Flow through
Solid Phase
Lateral Flow
Isothermal Nucleic Acid Tests

Immune Response to Dengue: Antibody Specificity
Increases over time
Acute Acute
Convalescent Convalescent
Day 0 7
NS-1: Effective days 1-5
post onset of symptoms
IgM/IgG: Effective after
day 5
A diagnostic capable of
detecting both is
desirable

2. SEROLOGICAL TEST BY ELISA –
TO DETECT ANTIBODY (IGM AND IGG)
Criteria for primary infection
Positive IgM after 5 to 7 days of
illness
Ig G present after 7 days
Criteria for secondary infection
Positive Ig G after 5 to 7 days onwards
 Usually Absence or slight increase in
IgM after 5 to 7 days onwards

144
 Most of the
studies have shown
that a combination
rapid test
comprising
immunochromatograp
hic assay for
detection of both
the NS1 Antigen
and the anti-dengue
Igm together yields
satisfactory clinical
results, instead of
sole NS1 antigen
detection.

 The IgM Capture or the MAC-ELISA is the most
widely used serological test
 Sensitivity 61.5-99%
 FDA approved MAC -ELISA in april 2011
 Serum, Saliva, dried blood sample collected in Filter
paper and CSF can be used as sample
 Can even detect a rise in dengue-specific IgM in acute
phase at 1-day to 2-day interval
 Specimens collected at an interval of 2-3 days
spanning the day of defervescence are usually
diagnostic
SEROLOGY: IGM CAPTURE ELISA

LAB (ELISA METHOD)
ELISA (serology)
MAC(IgM-Antibody-Capture)-ELISA, IgG
ELISA
Cross reactive with malaria, lepto, old
dengue infections
IgM/IgG (Primary infection >1.2 (1/100
dilution), >1.4 (1/20 dilution; secondary
infection if ratio is less) not standardized
IgA (peaks at Day 8 after fever;
undetectable by Day 40; cant distinguish
primary vs. secondary infections)

 Simple, sensitive and reproducible
 Reagents may be prepared locally
 Disadvantages:
 Pretreatment of serum samples reqd with
acetone/ kaolin and then adsorbed with type O
human RBCs to remove non-specific inhibitors of
agglutinin and non-specific agglutinins.
 Paired sera are required with a gap of at least 7
days.
 Can’t reliably distinguish between closely related
Flaviviruses: Between Dengue and Jap Encephalitis
SEROLOGY: HAEMAGGLUTINATION-
INHIBITION TEST (HAI)

HAEMAGGLUTINATION INHIBITION
TEST
152
Requires paired (acute, convalescent) sera
Does not discriminate between infections by
different flaviviruses

FEVER:
SEROLOGY: HAEMAGGLUTINATION-
INHIBITION TEST (HAI)
Ref: Dengue haemorrhagic fever: diagnosis, treatment, prevention and control.
2nd edition. Geneva : World Health Organization
The Interpretation of HAI results

NEUTRALISATION TESTS
156
 Plaque reduction and neutralisation assay, it’s a most specific serology
tool .
 Measures titer and neutralising antibodies
 Labor intensive, requires maintenance of very specific cell lines
 Limited to research lab.

TESTS USED FOR THE LAB DIAGNOSIS OF
PRIMARY DENGUE INFECTION (2)
Test Diagnostic
Window
Sample Required Sample Storage Turnaround Time Facilities/Cost
Antigen Detection 1-6 days Serum, tissues Refrigerate or
frozen
1 day or more
(histological)
ELISA facilities
($$), Histology
facilities ($$$)
IgM ELISA Day 5 to –Day 90
post infection
Serum, plasma,
blood
Frozen or
refrigerated
1-2 days ELISA facilities, $
IgM Rapid Test Day 5 to –Day 90
post infection
Serum, plasma,
blood
Frozen or
refrigerated
30 mins No additional
supplies, $
IgG (paired sera)
by ELISA, HI or
neutralization
Acute sera: 1-5
days;
Convalescent: after
15 days
Serum, plasma,
blood
Frozen or
refrigerated
7 days or more ELISA facilities,
BSL-2 for
neutralization, $

RAPID DIAGNOSTIC TESTS
(RDT’S)Important for:
• Quick diagnosis (lab results take time and
require labs)
• In resource-limited settings
• Alerts a unit to ID threats
• Helpful for triage during outbreaks
• Curtail geographic spread of infectious diseases
• Stability operations and infrastructure
building
Worldwide demand for better diagnostics to
Current RDT’s

IgG/IgM Dengue Duo kit (PANBIO)
10μL of serum, plasma, or whole blood
15 minute (time to result)
PRODUCT INFORMATION
NS-1/IgG/IgM Dengue Duo (SD)
120μL of serum or plasma
15 minute (time to result)

STANDARD DIAGNOSTICS DENGUE DUO (NS-1) RDT
NS1 Ag
3 drops (110 μl) of plasma or serum
for early acute phase samples (day 1 ~5)
IgG/IgM Ab
10 μl of plasma or serum for early convalescence
phase samples (after day 5 ~ 14)
Ag/Ablevel
Day
NS1 Ag
IgM
IgG
Ag/Ablevel
Day
NS1 Ag
IgM
IgG
1 2 3 5 7 10 12 1 2 3 5 7 10 12
Slide courtesy of Dr. Subhamoy Pal

INTERPRETATION
SecondaryPrimaryNegative

ADVANTAGES AND LIMITATIONS
OF DIFFERENT DENGUE DIAGNOSTIC TESTS
Diagnostic tests Advantages limitations
Viral isolation and identification • Confirmed infection
• Specific
• Identifies serotypes
• Requires acute sample (0–5 days
post onset)
• Requires expertise and
appropriate facilities
• Takes more than 1 week
• Does not differentiate between
primary and
secondary infection
• Expensive
RNA detection • Confirmed infection
• Sensitive and specific
• Identifies serotype and genotype
• Results in 24–48 hours
• Potential false-positives owing to
contamination
• Requires acute sample (0–5 days
post onset)
• Requires expertise and expensive
laboratory
equipment
• Does not differentiate between
primary and
secondary infection

ADVANTAGES AND LIMITATIONS OF
DIFFERENT DENGUE DIAGNOSTIC TESTS: SEROLOGY
Diagnostic Tests Advantages Limitations
IgM or IgG seroconversion • Confirmed infection
• Least expensive
• Easy to perform
• IgM levels can be low in secondary
infections
• Confirmation requires two or more
serum samples
• Can differentiate between primary
and secondary
infection*
IgM detection (single sample) • Identifies probable dengue cases
• Useful for surveillance, tracking
outbreaks
and monitoring effectiveness of
interventions
• IgM levels can be low in secondary
infections
*Primary infection: IgM-positive and IgG-negative (if samples are taken before day 8–10); secondary infection: IgG should be higher
than 1,280 haemagglutination inhibition in convalescent serum.

ADVANTAGES AND LIMITATIONS OF
DIFFERENT DENGUE DIAGNOSTIC TESTS: ANTIGEN
DETECTION
Diagnostic Test Advantages Limitations
Clinical specimens (for example,
using
blood in an NS1 assay)
• Confirmed infection
• Easy to perform
• Less expensive than virus isolation
or RNA
detection
• Not as sensitive as virus isolation
or RNA detection
Tissues from fatal cases (for
immunohistochemistry,
for example)
• Confirmed infection • Not as sensitive as virus isolation
or RNA detection
• Requires expertise in pathology

167
WHO: Guidelines for diagnosis, treatment, prevention and control Geneva 2009

CAN WE RULE OUT DENGUE FEVER IF NS1 ANTIGEN
IS NEGATIVE?
Answer : WE CAN NOT Rule out dengue fever
if NS1 antigen is negative
State your reasons
1. Its only useful in the diagnosing in the early phase as it is
detectable in the blood from 3 to 4 of illness . Some times
even from second day of illness. But It is not detectable
after 5 days of illness as its level will decline
2. Usually Negative NS1 antigen in secondary dengue
infection

169
Day of illness = 4
Ig M - Positive
Ig G - Negative
NS1 - Antigen Positive
Diagnosis – ?
SCENARIO 1

170
Dengue Fever–Primary infection

17
1
Day of illness = 4
Ig M Negative
Ig G Positive
NS1 Negative
Diagnosis - ?
SCENARIO 2

172
Dengue Fever–Secondary infection

173
Day of illness = 3
Ig M Negative
Ig G Negative
NS1 Positive
Diagnosis - ?
SCENARIO 3

17
4
Dengue Fever–Primary infection

DIFFERENTIAL DIAGNOSIS
The DDS of DF includes viral respiratory and
influenza like diseases. Early stages of Malaria ,
mild yellow fever, scrub typhus, viral hepatitis and
leptospirosis.
Four arboviral diseases have dengue like courses
but without rash – Colorado Tick fever, sand fly
fever, Rift valley fever and Ross river
Meningo Cocccemia , Yellow Fever other viral
hemorrhagic fevers, many in rickettsial diseases
and other severe illneses caused by a variety of
agents may produce clinical picture similar to DHF

178
1. Dengue Fever has no specific treatment , only supportive
care is provided
2. The Supportive care in dengue includes fluid replacement
and close monitoring of platelet and Hct
3. Dengue fever can be cured by antiviral
4. Platelet transfusion is given in Dengue Fever
5. Dengue vaccine is used in all the endemic countries
currently
6. Dengue vaccine is given to new born babies as preventive
method
7. We can advice the people above 45 years old to take dengue
vaccine
TRUE OR FALSE

MONITORING
 Patients should be monitored constantly
until there is a reasonable certainly that the
danger as passed in practice.
 Pulse, BP, RR & Temp. be taken every 15
to 30 minutes are more often until the
shock resolves.
 Hematocrit or Hb studies should be
performed every two hours for the first six
hours then every four hours thereafter
until the patient is stable.
 Accurate record of intake and output

182
Monitoring parameters :
 Body temperature
 Respiratory rate
 Heart rate
 Blood pressure
 Pulse pressure/ volume
 Capillary refill time
 Abdominal pain
 Bleeding
 Vomiting

MANAGEMENT=INTOTO
 There is no specific anti viral treatment .
 The management is essentially supportive
and symptomatic (Bedrest)
 The key to success is frequent monitoring
and changing strategies depending on
clinical and laboratory evaluations.
 Antipyretics or cold sponging should be
used to keep the body temperature < 40C.
 Analgesics and mild sedation may be
required to control pain

MANAGEMENT(1)
1st step: Is this dengue?
Live in/travel to dengue endemic area
Fever and 2 of the following:
Anorexia/nausea
Rash
Aches/pains
Warning signs
Leukopenia
TT positive
Laboratory confirmed dengue

MANAGEMENT (2)
2nd step: Warning Signs* present?
Abdominal pain/tenderness
Persistent vomiting
Clinical fluid accumulation
Mucosal bleed
Lethargy, restlessness
Liver enlargement >2cm
Lab: Increased Hct with rapid decrease
in Plt
*Requires strict observation and medical intervention

MANAGEMENT (3)
Classifications
Dengue without warning signs
May be sent home
Dengue with warning signs
IF Dengue is suspected, and has warning signs,
Dengue with no warning signs, BUT has co-existing
conditions or social circumstances
Referred for in-hospital care
Severe Dengue
Severe plasma leakage with shock and/or fluid accumulation
with respiratory distress
Severe bleeding
Severe organ impairment
Require emergency treatment

MANAGEMENT (4)
Dengue without warning signs
Patients who do not have warning signs AND
Able to tolerate PO fluids
Pass urine q6H
Lab: CBC: if stable Hct, can be sent home
Treatment: Bed rest, PO intake, paracetamol
4GM max/day
Monitoring: daily review for disease
progression:
Decreasing WBC
Defervescence
Warning signs (until out of critical period)
If any of these occur, return to hospital immediately

MANAGEMENT OF THOSE WHO DO NOT NEED
ADMISSION=OP TREATMENT
Following treatment measures are recommended:
Ensure adequate oral fluid intake of around 2500 ml for 24
hours (if the body weight is less than 50kg give fluids as
50ml/kg for 24 hours).
This should consist of oral rehydration fluid, coconut water,
other fruit juices, kanji or soup rather than plain water.
Exclude red and brown drinks which could cause confusion
withhaematemesis or coffee ground vomitus.commercial
carbonated drinks that exceed the isotonic level should be
avoided.

 Adequate physical rest
 Tepid sponging for fever
 Paracetamol not exceeding 2 tablets six hourly (reduce dose
for patients with lower body weights). Warn the patient that
the fever may not fully settle with paracetamol and advice
not to take excess.
 Anti-emetics and H2 receptor blockers if necessary
 Avoid all NSAIDS and steroids
 Withhold Aspirin, Clopidogrel & Dipyridamole in patients
who take these on long term basis

Advise immediate return for review if any of the
following occur:
 Clinical deterioration with settling of fever
 Inability to tolerate oral fluids
 Severe abdominal pain
 Cold and clammy extremities
 Lethargy or irritability/restlessness
 Bleeding tendency including inter-
menstrual bleeding or menorrhagia
 Not passing urine for more than 6 hours

MANAGEMENT (5)
Dengue without warning signs BUT has co-existing
conditions or social circumstances
 Co-existing conditions: pregnancy, infancy, old age, DM, renal failure
 Social circumstances: living alone, distance challenge
Lab: CBC
Rx: PO fluids, if not tolerated, start IV (0.9 NS or RL
at maintenance)
Monitoring:
 Temperature pattern
 I/O (Uop)
 Warning signs
 CBC (Hct, WBC, Plt)

MANAGEMENT (6) DENGUE WITH WARNING SIGNS
Lab: CBC=Rx
Obtain reference Hct before fluid treatment
Isotonic solutions (NS, RL) 5-7 mL/kg/hr for 1-2 hr, then 3-5
mL/kg/hr for 2-4 hr, then 2-3 mL/kg/hr or less per clinical
response
Reassess clinical status, Hct, fluid infusion rates
 If Hct same or min rise, 2-3 mL/kg/hr for 2-4 hr
 Crashing: increase rate to 5-10 mL/kg/hr for 1-2 hr
 Reduce IVF gradually when rate of plasma leakage decreases towards the end
of the critical phase: adequate Uop/fluid intake, Hct decreases below baseline
value in a stable patient
Monitoring
 VS, peripheral perfusion (q15min-1hr) until pt is out of critical phase
 Uop (4-6 hourly)
 Hct (pre- post IVF, then 6-12 hourly)
 Glucose
 Renal, hepatic, coags, CNS…prn

INDICATIONS OF HOSPITALIZATIONS
 Restlessness or lethargy frequent vomiting one or two
days of febrile illness.
 Cold extremities or circumoral cyanosis.
 Bleeding in any form.
 Rapid and weak pulse.
 Capillary refill time > 3 seconds.
 Narrowing of pulse pressure (<20 mm Hg) or Hypo
tension.
 Hematocrit of 40 or rising hematocrit.
 Platelet count of < 1,00000/ mm3
 Acute abdominal pain
 Evidence of Plasma leakage. Eg. Pleural effusion
/Ascities

MANAGEMENT (7)=SEVERE DENGUE
Lab: CBC, other organ function tests
Compensated Shock
IVF (isotonic crystalloid, 5-10 mL/kg/hr over 1 hr).
Reassess
If improved: decrease IVF gradually to 5-7 mL/kg/hr for 1-2 hr,
then to 3-5 mL/kg/hr for 2-4 hr, then to 2-3 mL/kg/hr for 2-4 hr,
then further per hemodynamic status
If unstable: Check Hct after first bolus
Hct increased/high (>50%): repeat second bolus of
crystalloid at 10-20 mL/kg/hr; improvement? Then
decrease to 7-10 mL/kg/hr for 1-2 hrs, continue to
wean…
Hct decreases: Cross match and transfuse blood
ASAP

MANAGEMENT (8)= HYPOTENSIVE SHOCK
 IVF resuscitation with crystalloids or colloids at 20 mL/kg as a bolus for 15
min
 Improved?
 Crystalloid/colloid solution (10 mL/kg/hr) for 1 hr, taper gradually
 Unstable?
 Review Hct taken prior to first bolus
 HCT low (<40% in children/adult females, <45% adult males): cross match and
transfuse!
 HCT high (WRT baseline): change to IV colloids at 10-20 mL/kg as a second
bolus over 30 min to 1 hr, reassess
 Improving: decrease rate to 7-10 mL/kg/hr (1-2 hrs), then back to IV
crystalloids and reduce rates as above
 Unstable: repeat Hct
 Decreased: bleeding…T/C, transfuse
 Increased/remains high (>50%): continue colloid (10-20 mL/kg) as a 3rd bolus (1 hr),
reduce to 7-10 mL/kg/hr (1-2 hr), change to crystalloid and reduce rate as above
 Hemorrhage: PRBC (5-10 mL/kg) or whole blood (10-20 mL/kg)

THE REPLACEMENT OF PLASMA
LOSS
Immediate replacement of
plasma loss with isotonic salt
solution (5% dextrose in ringer
acetate solution or 5% dextrose
in NS) at the rate of 10-20ml / kg
body weight are in case of
profound shock (grade-4) as a
bolus of 10ml/kg body weight (1-

ABCS
If the patient is not responding to two boluses
of crystalloid, contributory causes for shock
other than plasma leakage should be
considered. These
are,
Acidosis check venous blood gas (if present,
check liver and renal profiles)
Bleeding check HCT
Calcium and other electrolytes (sodium and
potassium) - check serum
Sugar check random capillary blood sugar

FLUID MANAGEMENT= COLLOIDS
Dextran 40 and plasma
Management of Shock :
DSS is a medical emergency that requires
prompt and vigorous volume replacement
therapy.
There are also electrolytes (sodium) and acid
base disturbances it must be consider that
there is a high potential for developing DIC.
And stagnant acidemia.
Blood will promote and or enhance DIC
which may lead to sever hemorrhage and or
irreversible shock.

It is important to correct these conditions as quickly
as possible.
If the patient is clinically acidotic one dose of 50 ml
of 8.4% sodium bicarbonate may be given
empirically if blood gas cannot be assessed.
Empirical treatment with 10% calcium gluconate 10
ml over 10 minutes is justifiable if a patient is in
shock and is not responding to adequate fluid
replacement, this may be continued six hourly.
IV calcium gluconate may be used in patients who
show evidence of myocardial involvement as well,
as hypocalcaemia is common in DHF patients and
calcium may improve the myocardial contractility
in such patients

If the blood glucose level is less
than 7 0 mg/dl correct it by giving
15 – 20g glucose orally or
intravenously. At the time of
shock, use
30–40 ml of 50% Dextrose (15-20g)
intravenously. Re-check capillary
blood sugar in 15 minutes and if it is
less than 7 0 mg/dl repeat 30-

D H F
DISCONTINUATION OF IV FLUIDS
WHEN:
The hematocrit reading drops to
around 40%
Vital signs are stable.
A good urine out flow indicates
sufficient circulate renal
volume.
A return of appetite and diuresis
are signs of recovery

D H F
MANAGEMENT (CONTD)
Sedations are needed in some cases
because of marked agitation.
Hepatotoxic drugs should be
avoided.
Chloral hydrate orally or rectally
recommended in a dose of 30 – 50

D H F
MANAGEMENT (CONTD)
In cases without pulmonary
complications paraldehyde
0.1ml/kg I.M. (maximum dose
10ml) also be use.
Oxygen therapy should be given
to all patients in shock. The
oxygen mask or tent may
increase apprehension.

MANAGEMENT OF FLUID OVERLOAD
Review the total intravenous fluid
therapy and clinical course and
check and correct for abcs.
All hypotonic solution should be
stopped .
Switch from crystalloid to colloid
solutions as bolus fluid .
Dextran 40 is effective as 10 ml/kg
bolus infusion , but the dose is
restricted to 30ml/kg/day because of

MANAGEMENT
BLOOD TRANSFUSION
Transfusion with fresh whole blood is
preferable and the amount to given
should be such that normal RBC
concentration is not exceeded.
Fresh Frozen Plasma (FFP) may be
indicated in cases where consumptive
coagulopathy causes massive bleeding.
DIC is usual in sever shock and may
play an important part in the
development of massive bleeding or
lethal shock.

MANAGEMENT
PLATELET TRANSFUSION
Platelet transfusion in cases of DHF / DSS is also
surrounded with controversies. Mild reductions in
platelet counts are usually not associated with
significant bleeding.
Secondly thrombocytopenia in DHF / DSS is a short
lived phenomenon with platelets returning to
normal by 7 to 9 days.
Platelet transfusions are recommended only for
children with platelet count of 50,000 / mm3 and
having significant bleeding manifestations.
Prophylactic platelet concentrate is indicated when
platelet count is less than 10000-20000 / mm3 (10

POLYSEROSITIES
Caution must be taken before drainage as the
chances of sever hemorrhages are high.
Patients should be haematologically stabilized first with use
of fresh whole blood, FFP or platelet concentrates and
drainage of these fluids should be done slowly to prevent
sudden circulatory collapse.
Large pleural effusions during the recovery phase after 48
hours may need small doses of frusemide (0.25 to 0.5 mg /
kg B/w 6th hourly) with these method it may possible to
avoid insertion of intercostal drains.
Generally steroids do not shorten the duration of disease or
improve the prognosis in children receiving careful
supportive therapy.

COMPLICATIONS
1- Febrile phase - Dehydration
2- Critical phase - Shock from plasma
leakage: severe haemorrhage; organ
impairment
= Dengue Shock Syndrome
3- Recovery phase - Hypervolaemia

MANAGEMENT OF HEPATIC ENCEPHALOPATHY IN DHF
Maintain adequate airway and oxygenation
Infuse minimal intravenous fluids sufficient to
maintain intravascular volume (80% of
maintenance)
Use hyper-oncotic colloid solution early if HCT is
increased
Infuse Mannitol to reduce intracranial pressure if
renal functions are normal
Take measures to maintain serum sodium in-
between 145-155 meq/L. (3% hypertonic saline
may be of use if Mannitol cannot be used, and if
serum sodium is very low)

Maintain blood sugar above 60 mg/dl
Give a single dose of Vitamin K 10 mg IV
Give Lactulose to maintain 3-4 bowel motions per
day. However, lactulose commonly causes
gaseous abdominal distension and this may
interfere with respiration in these patients and
may even cause aspiration
Treat with broad spectrum antibiotics, which are
not excreted through liver, if secondary bacterial
infection is suspected (Cefotaxime is preferred)
Oral Metronidazole may be used (supportive
evidence is limited)
Ventilate (IPPV) early, if the features of
encephalopathy are getting worse

Fresh Frozen Plasma (FFP) should not
be used routinely, but may be used if
there is active bleeding or prior to
invasive procedures.
(However, be aware of possible fluid
overload with FFP)
Bowel washes and enemas should be
avoided
There is no evidence to support the
use of L- Arginine L-Ornithine (LOLA)
or N-Acetyl Cysteine (NAC) in these
patients and therefore, use of which is

DENGUE IN CO-MORBID CONDITIONS
 Liver Disease:
 Baseline liver function tests (LFT) including
prothrombin time (PT) is of value when
dengue is suspected in patients with chronic
liver disease.
 If AST/ALT is very high the patient is likely to
develop neurological involvement (Hepatic
Encephalopathy) especially in those with
gastrointestinal (GI) bleeding.
 In such patients liver failure regime should
be used early .
 If baseline albumin level is low these

 Managing these patients with theminimum
amount of IV fluids to maintain
intravascular volume in order toprevent
respiratory distress (acute pulmonary
oedema) and/or heartfailure is crucial
 Prolonged PT or INR (>1.3) indicates that
these patientshave a tendency for more
bleeding and therefore Vitamin K1 IV
isrecommended.
 In addition, assessment of the degree of
bleeding andtransfusing adequate amount

Heart Disease
 The key consideration in patients with
heart diseases would be to identify the
underlying heart disease and the current
medication.
 These patients should be observed
carefully with close and continuous
monitoring preferably echocardiography
especially during the critical phase.
 Careful adjustment of IV fluid is the key to
success and to prevent complications.
 Those who are on anti-platelet or anti-

Myocardial Involvement in Dengue
 Global dysfunction of myocardial
contractility may be seen in DHF
patients who are in prolonged shock
and the most likely reason is
metabolic acidosis.
 However hypocalcaemia (which is a
common finding in DHFpatients with
moderate to large pleural effusion /
ascites) should be considered as well.
 Hence, if there is evidence of cardiac
dysfunction, acidosis
andhypocalcaemia should be

Empirical treatment with calcium is
justifiable if clinically indicated.
Myocarditis is an uncommon finding in
Dengue and is very unlikely to cause
death in a patient with DHF. However,
such a patient could easily develop
pulmonary oedema with fluid overload.
Therefore, if myocardial Involvement is
suspected fluid should be given very
carefully
Treatment of myocardial Involvement
is symptomatic.

Diabetes Mellitus:
 Frequent monitoring of blood sugar is important
from the time the patients are admitted to
hospital. All anti-diabetic drugs have to be
switched to insulin in order to keep blood sugar
level preferably below 150-200mg/dl.
 Closely monitor the patient and look for the
possible development of Diabetic Ketoacidosis
where patient will need more IV fluid, IV insulin
as an infusion and monitoring of central venous
pressure if possible.
 Manage the commonly associated conditions
with DM, e.g. hypertension

Renal Disease:
 The baseline renal function tests (Blood Urea,
Creatinine), electrolytes,acid-base balance,
GFR, urine output per day and urine analysis
should be performed during the early febrile
phase and regularly tested during the course of
the illness. Close monitoring of fluid intake and
urine output is very important.
 Fluid overload during convalescent phase is
the most important cause of death among
these patients. Early consultation with a
nephrologist and early planning of any renal
replacement therapy in those patients who are
oliguric with signs and symptoms of fluid

MANAGEMENT OF PREGNANT
PATIENTS WITH DF/DHF CLOSE TO
DELIVERY
Risk of bleeding is at its highest during the period of plasma
leakage therefore ,
Unless to save mothers life, avoid Lower segment caesarean
section during the critical ( plasma leakage ) phase.
Obstetric procedure should be avoided .
If obstetric procedure are to be undertaken ,Maintain the
platelet count above 50,000/mm3.
Single donor platelet transfusion is preferred , if available , if
platelet transfusion is necessary . If patient goes into
spontaneous labor during critical phase take steps to
prevent vaginal tears by performing an episiotomy.
Increase of fetal compromise priority should be given to the
mothers life .

222
Special population :
Pregnancy :
 Dengue in pregnancy must be carefully
differentiated from preeclampsia.
 An overlap of signs and symptoms, including
thrombocytopenia, capillary leak, impaired liver
function, ascites, and decreased urine output may
make this clinically challenging.
 Pregnant women with dengue fever respond well to
the usual therapy of fluids, rest, and antipyretics.
 If the mother acquires infection in the peripartum
period, newborns should be evaluated for dengue
with serial platelet counts and serological studies

MANAGEMENT (9)=SHOCK
PROMPT, judicious fluid resusctiation
Keep to minimum required to support CV stability
PREVENTIVE transfusions should be avoided
Desmopressin? IV gamma globulin?
Steroids? Drugs (chloroquine, balapiravir,
statins)? No evidence for efficacy
Beware pulmonary edema: may need PPV
 DHF-DSS is the 3rd most common cause of ARDS in hospitalized children in
Malaysia

224
 In DHF , blood transfusion is required (if significant
bleeding)
 Intravascular volume deficits should be corrected with
isotonic fluids such as Ringer lactate solution. Boluses
of 10-20 mL/kg should be given over 20 minutes and
may be repeated.
 If this fails to correct the deficit, the hematocrit value
should be determined. If it is rising, limited clinical
information suggests that a plasma expander may be
administered. Starch, dextran 40, or albumin 5% at a
dose of 10-20 mL/kg may be used.
 Patients with internal or gastrointestinal bleeding may
require transfusion, and patients with coagulopathy
may require fresh frozen plasma.

225
 After patients with dehydration are stabilized, they
usually require intravenous fluids for no more than
24-48 hours. Intravenous fluids should be stopped
when the hematocrit falls below 40% and adequate
intravascular volume is present.
Patients with dengue hemorrhagic fever or dengue
shock syndrome may be discharged from the hospital
when they meet the following criteria:
 Afebrile for 24 hours without antipyretics
 Good appetite, clinically improved condition
 Adequate urine output, stable hematocrit level
 At least 48 hours since recovery from shock
 No respiratory distress, platelet count greater than
50,000 cells/μL

226
Management :
General approach :
 Dengue fever is usually a self-limited illness.
 There is no specific antiviral treatment currently
available for dengue fever.
 Supportive care with analgesics, fluid replacement,
and bed rest is usually sufficient.
 Aspirin, nonsteroidal anti-inflammatory drugs
(NSAIDs), and corticosteroids should be avoided.
 Management of severe dengue requires careful
attention to fluid management and proactive
treatment of hemorrhage.

227
 The Novartis Institute for Tropical Diseases (NITD)
in Singapore is carrying out research to find
inhibitors of dengue viral target proteins to reduce
the viral load during active infection.
GOALS :
 Reduce mortality rate
 Decrease the progression of disease state
 Maintain hydration , platelet levels , hematocrit
levels
 Decrease the viral load in the body
 To reduce the complications associated with
dengue (cardiomyopathy , hepatic injury, seizures,
pneumonia etc.)

228
Factors that affect disease severity and prognosis
include the following:
 Patient age
 Pregnancy
 Nutritional status
 Ethnicity
 Sequence of infection with different dengue
serotypes
 Virus genotype
 Quality and extent of available medical care

DHF
http://www.pattayagogos.com/news08a.htm
http://denguehemorrhagicfever.tumblr.com/

230
Vaccine=challenges
 No vaccine is currently approved for the
prevention of dengue infection.
 Because immunity to a single dengue
strain is the major risk factor.
 so vaccine must provide high levels of
immunity to all 4 dengue strains to be
clinically useful.
 The precise mechanism of DHF/DSS
pathogenesis and the relationships
between viral load, cytokine storm,
coagulopathy, and complement
activation are uncertain.

T cells, play an important protective role in
controlling dengue virus infection, rather
than creating an aberrant response that can
ultimately worsen the disease as is the
prevailing current belief.
The current thinking in the field is that the
goal of a dengue vaccine should be the
induction of antibodies and not T cells.
Recent studies suggest that both cell types
are needed to produce a strong immune
response against dengue infection.
VACCINES=MECHANISM

VACCINATION=FUTURE
 Estimated availability in 5-10 years
 Tetravalent LA dengue virus strains
based on yellow fever –dengue virus
[CYD-TDV]
 Future directions : TV003 a single dose
of LATV – induced a trivalent or greater
Nab response in 90% of flavivirus-naive
adults
 Live attenuated tetravalent vaccines
under phase 2 trials

YFV 17D STRAIN ATTENUATED DV STRAIN
235

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 (larvicidal) treatment of water containers
used to kill immature aquatic stages
 Space spraying (thermal fogs)
 Indoor space spraying(2% pyrethrum),
organophosphorus compounds
 Ultra-low volume fumigation against adult mosquitoes
 Mosquitoes may have resistance to commercial
aerosol sprays

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

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 Education

WHY INCREASING
 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

Each Patient is a Book
Each Day is a Learning Opportunity
CME has More Relevance
Now Than Ever
TOGETHER WE LEARN
BETTER

CASE1
A. WHAT IS YOUR PROVISIONAL DIAGNOSIS ? STATE
YOUR REASONS ?
Fever, chills,
headache
Myalgia
Arthralgia
Nose
Bleeding
• Platelet : 90 000 /
mm3
• Hematocrit : 75%
• Low WBC Count
Normal
HCT Male: 40.7 to 50.3%
Female: 36.1 to 44.3%
Platelets 150,000 to 400,000 /
mm3

Answer : Dengue Haemorrhagic Fever
Reasons
 Fever
 Hemorrhagic manifestations – Nose
Bleeding
 Low platelet count (100,000/mm 3 or
less)
 Elevated hematocrit ( >20% then
normal for male )
247

B. WHICH LAB TEST YOU WILL ORDER TO CONFIRM
YOUR DIAGNOSIS ?
1
2
C. Interpret your Lab findings if your
result is positive for Dengue ?
1
2

B ) Answer : NS1 antigen Test - to detect NS1
antigen
Serological Test using ELISA – To
Detect Antibody( Ig M and Ig G )
C ) Answer : 1. Positive NS1 antigen if the illness is
less then 5 days .
2. Positive IgM if 5 to 7
days of illness suggesting a primary infection or
Positive Ig G if 5 to 7 days of illness onwards
suggesting a secondary infection.
249

CASE2
A. WHAT IS YOUR PROVISIONAL DIAGNOSIS ? STATE
YOUR REASONS ?
Fever, chills,
headache
Myalgia
Arthralgia
No signs of
bleeding
• Platelet : 90 000 / mm3
• Hematocrit : 50%
• Slightly Low WBC Count
Normal
HCT Male: 40.7 to 50.3%
Female: 36.1 to 44.3%
Platelets 150,000 to 400,000 /
mm3

251
Provisional diagnosis: Dengue Fever
without Haemorrhage / Classic Dengue
Fever
Reasons : Fever, chills,
headache,Myalgia,Arthralgia No signs of
bleeding(Clinical Symptoms) Low platelet
, low wbc (Lab Reasons)
(according to WHO, Fever plus any 2
clinical symptoms is sufficient to make
provisional diagnosis )

B. CNTD . WHICH LAB TEST YOU WILL ORDER TO
CONFIRM YOUR DIAGNOSIS ?
1
2
C. Interpret your Lab findings if your
result is positive for dengue ?
1
2

253
B ) Answer : NS1 antigen Test - to detect NS1 antigen
Serological Test using ELISA – To Detect
Antibody( Ig M and Ig G )
C ) Answer 1. Positive NS1 antigen if the
illness is less then 5 days .
2. Positive IgM if 5 to 7 days of
illness suggesting a primary infection or
Positive Ig G if 5 to 7 days of illness onwards
suggesting a secondary infection.

Dengue=total uptodate

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