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Dr. R.K.LUDAMDEPT OF COMMUNITY MEDICINEV.S.S. MEDICAL COLLEGE, BURLA

Introduction-:The word dengue is derived from African word denga: meaning fever with hemorrhage.Dengue is an acute arboviral disease caused by an arbovirus belonging to flabivirus & is primarily transmitted by Aedes mosquito.It presents in 3 different forms- -Classical Dengue Fever -DHF(Dengue hemorrhagic fever) -DSS(Dengue shock syndromeIt is self-limiting(sizable asymptomatic & occasionally ending fatality.

Problem Statement-:Prevalence has gone up in last few decades- -Before 1970 9 countries -Now 100 countries(Africa,America,SEA,Coast-pecific)First outbreak that resembles a disease now recognized as dengue fever was described by Benjamn Rush in Philadelphia, Pennsylvania 2500 million remain at risk.Most important reemerging mosquito borne viral disease.50 million cases are estimated to occur with 24,000 death.5 lakh require hospitalization.

Distribution Across The World

Epidemics is on the rise due to- -growing urbanization -poor sanitation & housing conditions -accumulation of discarded waste -improper solid waste disposal

SEAR,West pacific- 70% burden4,65,000 DALYSNo longer limited to urban population-also spreading to rural areas

In India-:First reported outbreak-18121956-Vellore Dist(TN)-Dengue 41963-Double peak hemorrhagic fever-Calcutta1982-Delhi-Dengue-I,II (1022 case-423 death)1996-Delhi-Dengue-II (7247 cases-297 death)2010- (25725 case- 99 death) ORISSA- 19 case- 0 deathHigh reporting DLH,Punjab,HaryanaAmong N.E states-Manipur-first reported in 07 and Meghalaya-in 2010 Reported from 23 States/UT.CFR has reduced from 3.3% in 96 to 0.57 in 09.

CHIEF REASONS OF OUTBREAK-:Un planned, unorganized urbanizationImproper waste management& water supply system.Increased vector density due to increase in vector breeding place.Leak of vector controlIncrease in spread due to increased population density.Of public health & surveillance system.

4 catagories of countries in SEARCAT-A-: (Indonesia,Myanmar,Thailand) -Increased hospitalization -Increased TDR among children -spread to rural population -multiple serotypes -Ae. Egypti & Ae. AlpopticusCAT-B-: (India,Maldives,Bangladesh,Srilanka) -Increased DHF -Cyclicalepidemic -Multiple serotype -Ae. egypti

CAT-C-: (Bhutan,Nepal) -Uncertain epidemics CAT-D-: (Korea) -Non-endmic

CLASSICAL DENGUE FEVER- -It is an acute viral condition caused by all the 4 types-Dengue (1,2,3,4). -It occurs both in epidemic & endemic form. -NSP-I(3), II-(6), III-(4), IV-(5) -Season-: -During & After Rainy season -Peak-October

It is due to accumulation of water.Temperature & Humidity-: 16c most conductive

TRANSMISSION-:

Mosquito- Aedes egypti (most efficient) Aedes albopticus Aedes polyniensis Aedes scultelaris

-Survives best in 16 to 30c (16 & 42 not suitable) RH-60 to 80%-Breeding site-It breeds in containers & peridomestic area-Eggs can survive for 1 yr without water-Life span 15 days-Highly anthropophilic-can infect a man with one bite.

Indoor resters in cool shady placeDay biter Multiple feeders multiple persons (cluster of cases)Flight range-400 mtrs max(usually 100mtrs) D- for Aedes mosquitoDengue & dengue haemorrhagic feverDry environmentDays-egg remain viable for longer duration.Do it again-bites repeatedlyDay time biterDiscarded bottle

Period of Communicability-:1 to 2 days before onset of fever to 4 to 5 days after that.Extrinsic IP- 8 to 10 days (Avg 6-7 days) -Once infected it remains so lifelong.Intrinsic IP- 3 to 10 days ( 5 to 6 days) -Very low critical density-3/10manhrcatch

Clinical Feature-:High rise of temperature with chill.Intense headache,myalgia,severe arthritis.Retro-bulbar pain in eye particularly with eye movement.Other constitutional symptoms like vomiting, anorexia etcSkin eruption occurs in 80% of cases during remission and second phase of illness & lasts for 1 to 2 days.Rashes which appear first may start with flushing, mottling & fleeting pin point rashes.

Rashes which appear on 3rd & 4th day of illness may start on chest,trunk.May spread to extremities & rarely on face and followed by desquamation. Fever may last for 5 to 7 days & self limiting and there may be protracted convalescence.CFR is very very lowInfection of one genotype give protection against another genotype but partially.

Case definition of DFSuspect- -Acute onset -High fever of 7 day duration -Severe headache, backache -Joint & muscular pain (Retro-bulbar pain)Probable- -Suspect case of DF -High vector density -Presence of a confirmed case in the area. -Blood ve for mp & not responding to anti- malarials.

Confirmed- -Isolation of virus in early phase. -Serology- Increased IgM in single sera,4 fold rise Ab in paired sera.

DHF(Dengue Hemorrhagic Fever)It is a severe manifestation of DF believed to be due to double infection with dengue virus.First infection probably sensitization & second probably immunological catastrophe.CFR is very high specially among children (15 yrs)

CLINICAL FEATURES-:Fever-Acute onset,increasing,lasting for 2-7 daysHeadache,vomiting,abdominal painIn first few days it resembles DF but rashes are not very common in DF.

Hemorrhagic Diathesis-: -Scattered fine patches on extremities,face,trunk & axilla. Torniquet test- +ve -Inflate the cuff=(syst+diast)/2 -Hold for 5 mins -Examine pete (Cubital fossa)- >20 ptc-3cm diameter +ve-Bleeding from gum,nose,GI tract are less common.- Hematuria is extremely rare.

Enlarged tender liver.50% of pts-Generalized lymphadenopathyCritical stage is reached 2-7 days whenever subsides.the temperature may drop suddenly.Therell be circulatory disturbances.

CASE DEFINITION OF DHF-:A)Suspect- -Acute onset of fever -Fever non structural glycoprotein (NS1t NS7)NS1 -Coincides with increased Viremia -So helps in early detection in early part filling -Increased sensitivity in early past (5 days) After 5 days-Ab detection (Commercial kits are also available)

GRADING-

Grade-I - Fever + Non-specific symptoms Torniquet test may be PositiveGrade-II - Gr I + Spontaneous Bleeding

Grade-III - Features of peripheral circulatory failure

Grade-IV - Profound Shock

Management-Management of DF-: -Bed rest -Paracetamol (avoid salicylates) -Home available fluids & ORSManagement of DHF-: -Bed rest -Antipyretics -Increased fluid intake -I.V Line -Plasma expanders -Plasma (frozen) -Blood Transfusion

Group-A (Classical DF) -: Home ManagementHospitalization- If a)No clinical improvement b)Severe abdominal pain c)Cold clamy extremities d)Lethrgy, irritability e)Bleeding f)Not passing Urine for > 6hrsGroup-B-: (Pts with warning signal) -Pts with pregnancy,infants,old age,DM,CKD -Management-:RL-Isotonic solution -5-7ml/kg - 1-2 hrs -3-5ml/kg - 2-4hrs

Group-C-: (Pts requiring urgent referral) -Severe plasma leakage -Severe hemorrhage -multi-organ involvement Fluid-5 to 10 ml/kg-first hour

Control Measures-:A.Mosquito control-

a).Source reduction-Empty water containers(once/wk) -Cover & seal septic tanks,soakage pits -Remove water from cooler,flower base b).Anti-Larval- Insecticidal spray -Household spray-2% pyrethrin ULV spray,Mosq net,insect repellents,full sleve cloth,keeping Pt away from mosquito bite.

Breeding Places & Control

CRUX OF PROBLEM-:

Surveillance-: House Index-%age of house +ve for Aedes larvaBreteau Index- No. of +ve container of AE larva/100HHContainer Index-%age of container +ve for Ae-breeding HighXm Low XmBr. Index >50 10%