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 heterotypicityand 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 Fever1. Fever or H/O acute fever lasting 2-7 days2. Hemorrhagic tendencies evidenced by at-

least one of – Positive tourniquet test– Petechiea / Ecchymosis– Bleeding from mucosa /GIT/ injection sites

or other locations3. Thrombocytopenia4. 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 non-

specific 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