Dengue Hemorrhagic Fever

Dengue hemorrhagic fever

Diagnosis, Treatment, Prevention and Control

Why Dengue–Emerging Health Problem Almost 1/3rd of the world in endemic areas – mostly SEAR countries (52%) Increase in Incidence and Frequency of epidemics Among 10 leading causes of pediatric hospitalization & death in SEAR Economic Burden – both Direct & Indirect cost Sporadic cases in Non-Endemic population poses diagnostic difficulty

South-East Asia

Indian Perspective Presently a category B country Endemic Transmission of all 4 serotypes leading on to heterotypicity and hence DHF Spreading of Geographic distribution of endemicity Absence of a concrete National Program – both Epidemic control as well as Endemic Surveillance

No of Cases & CFR - INDIA

KI DENGA PEPO Acute Febrile Arthopod-borne Arboviral illness Humans are the main amplifying host Dengue virus belongs to Flaviviridae with 4 serotypes (DEN-1 … DEN-4) Aedes aegypti, a day biting urban thriving mosquito is the primary vector Affects mainly tropical and sub-tropical areas

Clinical Features High fever with maculo-papular rash Severe headache/retro-orbital pain Arthralgia/myalgia Nausea/vomiting Petechiae/purpurae Hemorrhagic phenomenon – Epistaxis, gum bleeds, G I bleeding, hematuria, menorrhagia, ICH

Dengue hemorrhagic fever High fever Hemorrhagic phenomenon Hepatomegaly Hypovolemic shock

1/3rd cases of DHF progress to shock Clinical indicators Laboratory indicators

Dengue shock syndrome Cold and blotchy skin Circum-oral cyanosis Rapid pulse Hypotension/narrow pulse pressure Acute abdominal pain Interal bleeding

complications Shock Internal bleeding Pleural effusion/ascites Encephalopathy Liver failure Iatrogenic – Sepsis – Pneumonia – Overhydration

Laboratory findings Thrombocytopenia Hemoconcentration Leukopenia Hypoproteinemia Hyponatremia Increased SGOT Coagulation defects Heaptomegaly/pleural effusion/ascites

Laboratory Diagnosis Sample collection time – Acute sera (S1) – Convalescent sera (S2) – Late Convalescent sera (S3)

Sampling methods – Tubes/Vials, Filter-paper

Approaches – Virus – Antigen – Antibody – Genomic sequence

Approaches Viral culture In-situ hybridization Immuno-cytochemistry Reverse Transcriptase PCR amplification assay Serological methods – Cross-reactivity – Original Antigenic Sin

Serological methods MAC-ELISA Neutralization test Heme-agglutination inhibition test Complement fixation test Dot-Blot immunoassay

Case definition- Dengue fever Acute febrile illness with 2 or more of – Headache/retro-orbital pain – Arthralgia/myalgia – Rash – Hemorrhagic manifestation – Leukopenia

Either of – Supportive serology/positive IgM – Occurrence at the same location and time as other confirmed cases of DF

Dengue Hemorrhagic Fever 1. Fever or H/O acute fever lasting 2-7 days 2. Hemorrhagic tendencies evidenced by atleast one of – Positive tourniquet test – Petechiea / Ecchymosis – Bleeding from mucosa /GIT/ injection sites or other locations 3. Thrombocytopenia 4. Evidence of plasma leakage – Rise in hematocrit – Drop in hematocrit after hydration – Pleural effusion, ascites & hypoproteinemia

Dengue shock syndrome All 4 criteria for DHF must be present Evidence of circulatory failure manifested by – Rapid weak pulse – Narrow pulse pressure (<20 mm Hg) – Hypotension, cold, clammy skin – restlessness

WHO Grading of DHF Grade I – fever accompanied by nonspecific constitutional symptoms with a positive tourniquet test and/or easy bruising Grade II – acute febrile illness with spontaneous bleeding Grade III – Circulatory failure indicated by rapid weak pulse & hypotension or narrowing of pulse pressure Grade IV – profound shock with undetected blood pressure or pulse

Treatment Anti-pyretics Fluid loss correction – 10ml per kg x % body weight loss

Fluid maintanence For shock – 10-20 ml/kg bolus upto 20-30ml/kg – Plasma/plasma substitute/5% albumin – Fresh whole blood – Correction of electrolyte and acid-base imbalance

Prevention and Control Vector surveillance and control Fever surveillance Viral surveillance Case notification Control of outbreaks Vaccination – tetravalent live attenuated dengue vaccine

Vector Surveillance Objectives and Uses – Geographical distribution & density – Evaluate Control Programs

Sampling methods – Larval study, Collection on humans/of resting mosquitoes, Ovitrap, Tyre larvitrap & insecticide susceptibility

Indices – House, Container, Breteau – landing rate, Indoor resting density

Vector Control Environmental management – Improvement of water supply & storage – Solid waste management • Reduce, Reuse, Recycle

– Modification of man-made larval habitats

Chemical control – Against Lavae, pupae & ovum – Against adult mosquitoes

Biological control

Chemical Control Larvicide application – 1% temephos sand granules – methoprene

Perifocal treatment – malathion, fenthion, fenitrothion

Space spraying – Thermal fog – ULV – Mist

Biological Control No chemical contamination Specificity against target organism Self-dispersion into sites not easily treated by other means

Expense of raising the organism Difficulty in application and production Limited utility Effective only against immature stages

Confinement of an Outbreak At the individual level – Repellants, nets, coils & dresses

At the family level – Empty/cover/drain/apply larvicide

At the community level – Chemical control, community participation, supervision of houses

Pubic info through media legislation

References www.denguenet.com www.whosea.org Pubmed W H O publication 1997 Nelson text book of paediatrics Harrison’s text book of internal medicine Park’s text book of S P M