D E N G U EMARIA NIAZ

BS.MT 4TH SEMISTER

Introduction

• Dengue is a virus spread by Aedes mosquitoes that bite during the day.

• Unfortunately, there’s no vaccine to prevent it.

• The best you can do is avoid being bitten.

Pathogenecity

• Dengue is a virus serotypes DEN-1, DEN-2, DEN-3, DEN-4, cause dengue (DEN) and dengue haemorrhagic fever (DHF)

• These viruses are transmitted by Aedes mosquities

Dengue

Characterized by;

* High fever

* Headache

* Pain behind the eyes

* Pain in muscles

* Joints pain

* Enlarged lymph glands

* Maculopapular rash

Contd………

• Sometimes ;

* Abdominal pain

* Vomiting

• Occasionaly ;

* Haemorrhagic symptoms

Contd…………

• Virus enter into the blood circulation by multiplicatoin of virus in the reticuloendothelial system

• Leucopenia is the most infectious cause

http://images.google.com/imgres?imgurl=http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/17148.jpg&imgrefurl=http://www.nlm.nih.gov/medlineplus/ency/imagepages/17148.htm&usg=__AyzwzxZL6xGHsWnmp5h9HB9tYSs=&h=320&w=400&sz=16&hl=en&start=1&um=1&tbnid=NkTJCqQ5kB_KaM:&tbnh=99&tbnw=124&prev=/images%3Fq%3Ddengue%26hl%3Den%26rls%3Dcom.microsoft:en-US%26sa%3DN%26um%3D1

Contd……………

• Early infections are misdiagnosed by ; * malaria * hepatitis * flu-like illness

• High infectious rates occur in epidemics (70%-80%) of populations can de affected

Dengue haemorrhagic fever• Serious life-threatening condition

• Frequently children and others are affected whom previously infected with one serotype or strain of dengue virus and subsequently become reinfected with a different serotype or strain

• The secondary immue response leads to the formation of virus-antibody immune complexes which activate complement

Contd………

• These complements are causing vascular damage and dissaminated intravascular coagulation (DIC) with spontaneous bleeding

• In some patients, DHF progresses to circulatory collapse, referred as dengue shock syndrome (DSS)

Contd………..

DHF is characterized by;

• Raised haematocrit (PCV) due to plasma leakage

• Redused platelet count

• Hepatomegaly

• Haemorrhagic symptoms with bleeding into the skin

Dengue strikes

Go for performing dengue tests in serology laboratory of Liaquat National Hospital

Dengue test

• Dengue test performe by the immunochromatographic method using the BIAS-3 (bi-directional immuno assay system) dengue IgG/IgM kit use in LNH microbiology lab

• BIAS-3; two step assay for the differential detection of IgG or IgM antibodies to dengue virus in serum or whole blood

• Use for in vitro diagnosis

Principle of the test

• This test is the membrane based screening test to differentialy detect the presence of antibodies to dengue virus

• Lateral flow immunochromatographic type assay

• Once the sample is added to the sample pad along with diluent the mixture passes bi-directionally through two antibody binding complexes which then binds the imunoglobulins in the sample

Contd………..• The complex passes over the immobilized antigens

on the membrane, if any antibodies to dengue (IgG or IgM) are present the antigens capture them in turn

• This produces a pink/purple band in the test-zone of the device

• The remaining complex continues to migrate to a control area on the test device and produces a pink/purple band each control area

• This control bands indicate that the test has been performed properly

Kit components

• BIAS-3 Dengue IgG/IgM test device

• Diluent in dropper vial

• Directions for use

Dengue rapid test device

Stability and Storage Conditions

• The BIAS-3 Dengue IgG/IgM test kit is stable at any room temperature between 8-30C when in the unopened pouches.

• DO NOT FREEZE the kit or expose to temperature extremes.

• Stability of the kit is 24 months from the date of manufacture - dating is indication on the kit label.

General Precautions

• The test is for In Vitro Diagnostic Use only

• Appropriate infection control and handling procedures should be followed - do not smoke, eat or drink in the area where the test is to be performed. Use suitable clothing and gloves when handling samples and when performing the test

Sample Collection

• The BIAS-3 Dengue IgG/IgM test can be run on serum or whole blood

• The test works best on fresh samples.

• If testing cannot be done immediately, they should be stored at 2-8C after collection for up to 3 days

• If testing cannot be done within 3 days, serum can be stored frozen at -20C or colder

Test Procedure

• For WHOLE BLOOD - add 10 uls of sample to the center sample pad hole (S) of the test device using a measuring pipet.

• For SERUM - add 5 uls of sample to the center sample pad hole of the test device using a measuring pipet.

Contd…………• Follow sample addition with 6drops of the

diluent provided in the dropper bottle by holding the bottle vertically over the hole in the center sample pad cover. SLOWLY add diluent 1-2 drops at a time waiting for the previous drops to absorb

• Results are then read in as little as

5minutes for strong positives or upto 30minutes for weaker positives and to make sure negatives are confirmed

Reading the Test Results

NegativeNegativeOnly one pink/purple band appears in the Control areas of the BIAS test device.

Contd………PositivePositive

One or Two pink/purple bands appear in the Test area of the BIAS test device and one line each in the Control area of the test device

Quality Control

• It is recommended that a known positive and negative control be run to insure proper performance

• All controls should be handled in the same manner as patient samples

http://images.google.com/imgres?imgurl=http://mercopress.com/images/uploads/MEDICINE_dengue.jpg&imgrefurl=http://en.mercopress.com/2009/02/18/bolivia-dengue-death-toll-increases-malaria-outbreak&usg=__W5cB86bOFeqduEHMQymn1q_Ch04=&h=320&w=320&sz=45&hl=en&start=58&um=1&tbnid=eRri0AH2dvHtzM:&tbnh=118&tbnw=118&prev=/images%3Fq%3Ddengue%26ndsp%3D20%26hl%3Den%26rls%3Dcom.microsoft:en-US%26sa%3DN%26start%3D40%26um%3D1

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