Dengue and Chikungunya

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Dengue & ChikungunyaPrevention and Control : 

Dengue & ChikungunyaPrevention and Control Dr.H.R.V.Rajkumar M.D. Consultant Microbiologist Kamineni Hospitals Hyderabad

Dengue Virus : 

Dengue Virus Causes Dengue and Dengue hemorrhagic fever. Arbovirus – belongs to the family Flaviviridae Composed of ss RNA. Has 4 serotypes – DEN-1, DEN-2, DEN-3, DEN-4.

Dengue Virus : 

Dengue Virus Each serotype provides specific lifetime immunity, and short-term cross-immunity All serotypes can cause severe and fatal disease Genetic variation within serotypes Some genetic variants within each serotype appear to be more virulent or have greater epidemic potential

Transmission : 

Transmission Aedes aegypti

Slide 5: 

MOSQUITO FEEDS/ ACQUIRES VIRUS VIRUS MULTIPLIES 8-12 DAYS BITES UNINFECTED PERSON AFTER 4-7 DAYS INFECTED PERSON DEVELOPS DENGUE FEVER Man – Mosquito - Man

Dengue Clinical Syndromes : 

Dengue Clinical Syndromes Undifferentiated fever Classic dengue fever Dengue hemorrhagic fever or DHF Dengue shock syndrome or DSS

Undifferentiated Fever : 

Undifferentiated Fever Most common manifestation of Dengue. > 85% are either asymptomatic or only mildly symptomatic. “Silent” dengue transmission.

Dengue Fever(Break Bone Fever, Dandy Fever) : 

Dengue Fever(Break Bone Fever, Dandy Fever) Fever Head ache Joint pains Vomiting Rash

Dengue Hemorrhagic Fever : 

Dengue Hemorrhagic Fever Severe form of Dengue fever. Occurs 3-5 days after onset of fever. Features Acute fever (1020F – 1040F). Hemorrhagic manifestations. Low platelet count (< 1 lakh/cu.mm or less). Evidence of “leaky capillaries”. elevated hematocrit (20% or more over baseline) low albumin pleural or other effusions

Hemorrhagic manifestations of DHF : 

Hemorrhagic manifestations of DHF Petechiae Gingival bleeding Epistaxis GIT Bleeding Hematemesis Melena Hematuria Increased menstrual flow

Danger signs in DHF : 

Danger signs in DHF Severe abdominal pain. Prolonged vomiting Abrupt change from fever to hypothermia, with sweating and prostration Change in mental status of the patient – Restlessness or sleepiness. All these are warning signs that patient might be developing Dengue Shock Syndrome. Typically develops 3-6 days after onset of fever

Four grades of DHF : 

Four grades of DHF Grade 1 Fever and nonspecific constitutional symptoms Positive tourniquet test is only hemorrhagic manifestation Grade 2 Grade 1 manifestations + spontaneous bleeding Grade 3 Signs of circulatory failure (rapid/weak pulse, narrow pulse pressure, hypotension, cold/clammy skin) Grade 4 Profound shock (undetectable pulse and BP)

Dengue Shock Syndrome (DSS) : 

Dengue Shock Syndrome (DSS) Features of DHF Evidence of circulatory failure Rapid and weak pulse Narrow pulse pressure (≤ 20 mm Hg) or hypotension for age Cold, clammy skin and altered mental status Profound shock (undetectable pulse and BP)

Risk Factors Reported For DHF : 

Risk Factors Reported For DHF Virus strain Pre-existing anti-dengue antibody Previous infection Maternal antibodies in infants Host genetics Age Higher risk in secondary infections Higher risk in locations with two or more serotypes circulating simultaneously at high levels

Increased probability of DHF : 

Increased probability of DHF Hyperendemicity Increased circulation of viruses Increased probability of secondary infection Increased probability of occurrence of virulent strains Increased probability of immune enhancement Increased probability of DHF

Pathogenesis of DHF : 

Pathogenesis of DHF Neutralizing antibody to Dengue 1 virus Dengue 1 virus Non-neutralizing antibody Complex formed by neutralizing antibody and virus

Pathogenesis of DHF : 

Pathogenesis of DHF Non-neutralizing antibody to Dengue 1 virus Dengue 2 virus Complex formed by non-neutralizing antibody and virus

Pathogenesis of DHF : 

Pathogenesis of DHF Non-neutralizing antibody Dengue 2 virus Complex formed by non-neutralizing antibody and Dengue 2 virus Increased release of vasoactive amines

Clinical Evaluation In Dengue Fever : 

Clinical Evaluation In Dengue Fever Blood pressure Evidence or bleeding in skin or other sites Hydration status Evidence of increased vascular permeability – pleural effusions, ascites Tourniquet test Petechiae Positive Torniquet test

Laboratory Tests In Dengue Fever – Dengue Specific Tests : 

Laboratory Tests In Dengue Fever – Dengue Specific Tests Virus isolation From serum obtained during febrile phase of illness (< 5 days) Antibody detection IgM antibody capture ELISA (MAC ELISA) IgM & IgG antibodies by ELISA Two samples are taken S1 – As soon as patient is admitted S2 – Before discharge (gap of 14-21 days) Commercial dengue blot assay Newer tests RT PCR Hybridization assay

Laboratory Tests In Dengue Fever – Dengue Specific Tests : 

Laboratory Tests In Dengue Fever – Dengue Specific Tests Virus isolation Cell culture Virus isolation Cell culture Virus isolation Mosquito inoculation ELISA Test

Laboratory Tests In Dengue Fever – Other Associated Tests : 

Laboratory Tests In Dengue Fever – Other Associated Tests Complete Blood Picture ↓ Neutrophils, ↓ Platelets, ↑ Hemetocrit Liver function tests - ↑ AST Serum protein and albumin - ↓ PT and aPTT- Prolonged Urine analysis – Microscopic hematuria

Treatment of Dengue Fever : 

Treatment of Dengue Fever Fluids Rest Antipyretics like paracetamol (Avoid other NSAIDs) Monitor blood pressure, hematocrit, platelet count, level of consciousness.

Treatment of Dengue Fever : 

Treatment of Dengue Fever Continue monitoring after defervescence If any doubt, provide intravenous fluids, guided by serial hematocrits, blood pressure, and urine output The volume of fluid needed is similar to the treatment of diarrhoea with mild to moderate isotonic dehydration (5%-8% deficit)

Treatment of Dengue Fever : 

Treatment of Dengue Fever Avoid invasive procedures when possible Unknown if the use of steroids, intravenous immune globulin, or platelet transfusions to shorten the duration or decrease the severity of thrombocytopenia is effective Patients in shock may require treatment in an intensive care unit

Indications of Hospital Discharge : 

Indications of Hospital Discharge Absence of fever for 24 hours (without anti-fever therapy) and return of appetite Visible improvement in clinical picture Stable hematocrit 3 days after recovery from shock Platelets ≥ 50,000 / mm3

Dengue Vaccine ? : 

Dengue Vaccine ? No licensed vaccine at present Effective vaccine must be tetravalent Field testing of an attenuated tetravalent vaccine currently underway Effective, safe and affordable vaccine will not be available in the immediate future

Chikungunya Virus : 

Chikungunya Virus Causes Chikungunya In Swahili language means “that which bends up” Also an arbovirus Belongs to Genus Alpha virus & Family Togaviridae

Transmission : 

Transmission Aedes aegypti

Slide 30: 

MOSQUITO FEEDS/ ACQUIRES VIRUS VIRUS MULTIPLIES 8-10 DAYS BITES UNINFECTED PERSON AFTER 4-7 DAYS INFECTED PERSON DEVELOPS FEVER Man – Mosquito - Man

Clinical manifestations of Chikungunya : 

Clinical manifestations of Chikungunya Fever Joint pains Fever: Sudden onset – 1020F-1040F Brief febrile episodes May be associated with chills Severe joint pains Small joints more than large joints Pain increases during morning and with exercise

Clinical manifestations of Chikungunya : 

Clinical manifestations of Chikungunya Head ache Rash Conjunctival injection

Slide 33: 

CAN ANY BODY DIE OF CHIKUNGUNYA

TILL TODAY NO DEATHS HAVE BEEN REPORTED DUE TO CHIKUNGUNYA : 

TILL TODAY NO DEATHS HAVE BEEN REPORTED DUE TO CHIKUNGUNYA NO

Complications Of Chikungunya : 

Complications Of Chikungunya The only complication reported is persistence of joint pains sometimes for several weeks to months

Laboratory Tests In Chikungunya : 

Laboratory Tests In Chikungunya Virus isolation MAC ELISA Detection of antibodies (IgM & IgG) by ELISA RT PCR ELISA Test PCR These tests are available in only specialized centres

Treatment of Chikungunya : 

Treatment of Chikungunya Fluids Rest. Strain can increase joint pains Antipyretics like paracetamol (Avoid other NSAIDs) Chloroquine phosphate Avoid steroids

Control of Dengue / Chikungunya : 

Control of Dengue / Chikungunya No drug or vaccine is available. With early detection and proper case management and symptomatic treatment, mortality can be reduced substantially. The control of Aedes Aegypti mosquito is the only method of choice

Slide 39: 

Vector Aedes aegypti D engue Chikungunya

Aedes aegypti (Tiger Mosquito) : 

Aedes aegypti (Tiger Mosquito) Small, black mosquito with white stripes and is approximately 5 mm in size. Day biter with increased biting activity 2 hours after sunrise and several hours before sunset. Mainly feeds on human beings in domestic and peridomestic situations Bites repeatedly

Aedes aegypti (Tiger Mosquito) : 

Aedes aegypti (Tiger Mosquito) Resting habits Domestic and peridomestic situations Dark corners of the houses, on hanging objects like clothes, umbrella, etc. or under the furniture Outside rests in cool shady places. Breeding habits Breeds in any  type of man made containers or storage containers having even a small quantity of water Eggs of Aedes aegypti can live without water for more then one year

Breeding Places : 

Breeding Places

Breeding Places : 

Breeding Places

Breeding Places : 

Breeding Places

Control of Aedes aegypti : 

Control of Aedes aegypti Environmental management Environmental modification Improved water supply Mosquito-proofing of overhead tanks or underground reservoirs Changes in human habitat Draining of water supply installations Draining of temporary water collections in distribution pipes, water meter chambers, valve chambers etc. Proper storage of domestic water Covering water storage containers with lids or screen

Control of Aedes aegypti : 

Control of Aedes aegypti Flower pots/vases Punctured to produce a drain hole Keep live flowers in a mixture of sand & water Scrub clean weekly Incidental water collections Drainage & cleaning of water in air coolers, collection pans under refrigerators & in ACs. Building exteriors Regular inspection for any blockage of drainage pipes of roof tops, sunshades, porticos

Control of Aedes aegypti : 

Control of Aedes aegypti Solid waste disposal Discarded tins, bottles, buckets – buried in land fill House hold & garden utensils – buckets, bowls, watering devices – keep upside down Proper disposal of coconut shells Automobile tyre management Tyre depots always kept under cover Recycling & re use of used tyres in a proper way Glass bottles & Cans Bury in land fills / crush / recycled

Control of Aedes aegypti : 

Control of Aedes aegypti Personal Protection Protective clothing Full hands shirts, pants & socks (especially for school going children) Impregnation of clothes with permethrin Mats / Coils / Aerosols Day time – Children & Old people Repellents Natural: Plant oils – Citronella oil, Lemon grass oil, Neem oil Chemical: DEET Permithrin impregnated clothes

Control of Aedes aegypti : 

Control of Aedes aegypti Insecticide Treated Mosquito Nets & Curtains Limited utility – because not used in day time To protect infants & night duty people (who sleep by day) “OLYSET NET” – Contains 2% Permethrin (Malaysia / Vietnam) Door and window screens should be tight-fitting and must be in good condition.

Control of Aedes aegypti : 

Control of Aedes aegypti Biological Control Fish Larvivorous fish (Gambusia, Guppy) Depends on type of containers Bacteria Endotoxin producing Bacillus thuringiensis, Bacillus sphaericus Available as – wettable powders / tablets / pellets Cyclopoids Larvivorous Suitable for large containers – not cleaned regularly (wells, concrete tanks etc.)

Control of Aedes aegypti : 

Control of Aedes aegypti Chemical Control Chemical larvicides Used for domestic use containers that cannot be destroyed or eliminated Used only in short term high risk situations Temephos 1% Sand granules Effective for 8-12 weeks Insect growth regulators Interferes with development of larva or pupa Methoprene (Altosid) Do not cause immediate mortality of mosquitoes

Control of Aedes aegypti : 

Control of Aedes aegypti Space sprays (fogging) Indoor space spraying Pyrethrum extract can be used 1 part of 2% pyrethrum extract + 19 parts of kerosene (1 liter + 19 liters) 1 liter comes for 20 houses (100 cu.m space each) Flit pump or Hand operated fogging machine can be used Easy to use, non-toxic, cheap equipment, no resistance among mosquitoes reported

Control of Aedes aegypti : 

Control of Aedes aegypti Space sprays (fogging) Outdoor space spraying Thermal fogging Insecticide vaporized at very high temperature in a machine→ Fog spreads in different directions with wind→ On contact with cooler air→ Condenses to form a fine cloud of droplets Malathion, Pyrethrum can be used Equipment – Portable thermal fogger, Mist blowers, Vehicle mounted machines

Control of Aedes aegypti : 

Control of Aedes aegypti Space sprays (fogging) Outdoor space spraying Ultra Low Volume (ULV) Spray Very small droplets of insecticide is sprayed into air Remain suspended in air for sometime Driven under influence of wind No diluents used. No visible fog. Malathion is used commonly Equipment – Portable motorized knapsack blowers, Cold aerosol generators

Control of Aedes aegypti : 

Control of Aedes aegypti Thermal fogging Lesser active ingredient of insecticide Reduced operator exposure to insecticide Visible fog – Sense of satisfaction among people Expensive due to high cost of solvent and application Large volumes of diluent – not environment friendly High temperature of the machine operations and use of organic solvents – risk of fire hazards ULV Spray Less use of insecticide and minimal amount of diluent Reduced operator exposure Low fire hazard and more environment friendly Efficient application because of use of finer size droplets at higher density with less volume of insecticide Not visible like thermal fog No visibility reduction while fogging Cost effective because no diluent is used

Slide 56: 

Clean Environment Healthy life Thank you