DENGUE IS

DENGUE

DENGUEPRESENTOR: Nurdeza N. Puntukan Jay G. CayaBSMT-4A

Laboratory Investigation _Dr Salmah Idris_Microbiologist_ Hospital Sungai Buloh (ppt)https://en.m.wikipedia.org/wiki/Dengue_fever

Reference:DengueDengue VectorMode of TransmissionSerological testing for DenguePreventionTreatmentTable of ContentTo be able to know what is:DengueCausative agentHow it is being transmittedThe different test in determining if person has dengue.Prevention and treatment.Objectives:What is Dengue?Dengue fever also known asbreakbone fever, is amosquito-bornetropical diseasecaused by thedengue virus.

The dengue virus is carried and spread by mosquitoes in the genus Aedes, which includes a number of mosquito species. Of these species, the primary vector of the dengue virus is the speciesAedes aegypti. It is the principal dengue vector responsible for dengue transmission and dengue epidemics. Other mosquito species in the genusAedes includingAedes albopictus,Aedes polynesiensis, andAedes scutellaris have a limited ability to serve as dengue vectors.Dengue vectorAedes aegyptiDengue viruses are mainly transmitted by the bite of infectedAedes aegypti mosquitoes; an invasive, domestic species with tropical and subtropical worldwide distribution that originated in Africa

Aedes Aegypti Life Cycle:The dengue virus is spread through a human-to-mosquito-to-human cycle of transmission Typically, four days after being bit by an infected Aedes aegyptimosquito, a person will develop viremia, a condition in which there is a high level of the dengue virus in the blood.Mode of TransmissionViremia lasts for approximately five days, but can last as long as twelve days. On the first day of viremia, the person generally shows no symptoms of dengue. Five days after being bit by the infected mosquito, the person develops symptoms of dengue fever, which can last for a week or longerSerological test in Determining DengueAntibody detection- SerologyViral IsolationDetection of virus genetic materialDengue Virus Antigen or protein

IgM capture enzyme-linked immunosorbent assay (ELISA)Widely usedIgM titre is higher in primary compared to secondary infectionPeak at about 2 weeks and undetectable level by 60 90 days.

Dengue IgM testPrimary Dengue55% detectable between 4-7 days100% after day 7Secondary 78% after day 728% of secondary dengue infections were undiagnosed when IgM was the only test performed

Dengue IgM captured ELISAPrimary and secondary dengueIgG was detected in 100% after day 7 of illnessRecommended if dengue IgM is still negative after day 7 in secondary dengue

Indirect IgG ELISA

Gold standardLabour intensive and gold standardPaired samples for interpretation (Acute and convelescant samples 2 weeks apart) Research purposesDifferentiate between primary and secondary dengue infection

Haemagglutination Inhibition Test (HI)ImmunochromatographyQualitative detection of IgM and IgGYield is higher when samples were collected later in the convalescent phase of infectionGood specificity and could be used when ELISA facilities were not available

Dengue rapid testFalse positiveCross react withFlavivirus- Non-flavivirus malaria, leptospirosis, toxoplasmosis, syphilis*Connective Tissue Disorder

Definitive test for dengue infectionLab equipped with tissue culture facilitiesUseful only at early phase of illness , blood collected before day 5 of illness ( before the formation of Neutralizing antibodies)During febrile illnessVirus can be isolated from serum, plasma and leucocytesPost mortem specimensExpensive and time consuming (2 weeks to complete

Virus IsolationVirus isolation has a poor yield if compared with molecular test. IT most probably due to the viability of the virus and the quality of samples.

Virus IsolationEg. RT-PCR Diagnosis of dengue infection in the early phase (< 5 days of illness)Sensitivity 100% in the first 5 days of illness, reduced to 70% by day 6.Determine dengue serotype

Polymerase Chain Reaction (PCR)LimitationAvailable in certain facilities and trained personalTest is expensiveSpecimens requires special storage temperatures and short transportation , time between collection and extractionUse only be considered for in-patients who present with diagnostic challenges in the early phase of illness.Polymerase Chain Reaction (PCR)Highly conserved glycoprotein that seems to be essential for virus viabilitySecretion of the NS1 protein is a hallmark of flavivirus infecting mammalian cellsDengue infection, yellow fever and West NileHigh concentration in the sera of dengue infected patients during the early phase of the disease.

Non-structural protein -1 (NS1 Ag)Detection rate is much better in acute sera of primary infection (75% - 97.3%) when compared to acute sera of secondary infection (60%-70%)

The sensitivity drops from day 4-5 of illness and usually becomes undetectable in the convalescence phase.NS1 Antigen

There is no specific medicine to treat dengue infection. If you think you may have dengue fever, you should use pain relievers with acetaminophenand avoid medicines withaspirin, which could worsen bleeding. You should also rest, drink plenty of fluids, and see your doctor. If you start to feel worse in the first 24 hours after your fever goes down, you should get to a hospital immediately to be checked for complications.

Treatment for Dengue FeverAs yet, there is no effective vaccine against dengue fever. Therefore, the best prevention is to avoid being bitten by mosquitoes by paying attention to the following:

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Prevention Protect Yourself against Dengue Fever

31 Control the Spread of Dengue FeverPrevent the patient from being bitten by mosquitoes.3132Prevention of Mosquito BitesApply DEET-containing mosquito-repellents over exposed parts of the body and clothes every 4 to 6 hours.

For DEET products used by children, its concentration should be less than 10%.

33Prevention of Mosquito Bites

Your place of accommodation should have air-conditioners or mosquito nets. Otherwise, hang mosquito screens around your bed, use insecticides or coil incenses to repel mosquitoes.

34Elimination of Mosquitoes

The most effective way to eliminate mosquitoes is tokeep the environment clean and to remove stagnant water so that mosquitoes cant breed.35Elimination of Mosquitoes

Cover water containers tightly so that mosquitoes cant get in to lay eggs.


Dispose of domestic wastes properly to prevent the accumulation of stagnant water.

Dispose of empty bottles, cans and lunchboxes properly, such as into a covered bin.


Change water for vases and aquatic plants at least once a week, leaving no water under the pots or in the bottom saucers.

Scrub the container surfaces thoroughly to prevent mosquito eggs sticking on them.38Elimination of Mosquitoes Remove or puncture any dumped tyres to prevent the accumulation of stagnant water.


Ditches should be free from blockage.40Elimination of Mosquitoes

Fill up uneven ground surfaces to prevent the accumulation of stagnant water.41Elimination of Mosquitoes

Remove stagnant water immediately if mosquitoes are found to be breeding. Use environmentally friendly insecticides such as lavicidal oil if necessary.What is the causative agent of Dengue Virus?What is the gold standard in detecting Dengue Virus?What are the antibodies use in detecting dengue fever?Why is that patients suspected with dengue cant take aspirin?Give at least one way in preventing dengue.

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DENGUE IS

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