Dengue ppt

D E N G U E D E N G U E

MD.KABIUL AKHTER ALI Vector Borne Disease Consultant

NVBDCP, NRHMDistrict Heath & Family Welfare Samiti

Uttar Dinajpur

Distribution Endemic in more than Endemic in more than

100 tropical and 100 tropical and subtropical countries subtropical countries

Pandemic began in South Pandemic began in South East Asia after WW II East Asia after WW II with subsequent global with subsequent global spread spread

Several epidemics since Several epidemics since 1980s1980s

Distribution is comparable Distribution is comparable to malariato malaria

EpidemiologyEpidemiology

In India first outbreak of dengue was recorded in 1812

A double peak hemorrhagic fever epidemic occurred in India for the first time in Calcutta between July 1963 & March 1964

In New Delhi, outbreaks of dengue fever reported in 1967,1970,1982, &1996

Burden of disease in S.E. AsiaBurden of disease in S.E. Asia

CATEGORY-A(INDONESIA,MYANMAR & THAILAND)

CATEGORY-B (INDIA,BANGALADESH,MALDIVES & SRILANKA)

CATEGORY-C (BHUTAN, NEPAL)

CTEGORY-D (DPR KOREA)

Dengue Endemic Areas(1996 to 2010 = 29 States/UTs)

Risk factors:

•Construction activities

• Water storage practice

•Population movement •Heavy rainfall

•Vector abundance

Dengue Fever Dengue endemic in 29 States/UTs, upsurge observed in 2010Dengue endemic in 29 States/UTs, upsurge observed in 2010 States reported higher numbers of cases in 2010 (as on Dec 31)States reported higher numbers of cases in 2010 (as on Dec 31)

Dengue being reported from newer areas (Assam, Meghalaya, Dengue being reported from newer areas (Assam, Meghalaya, Chhattisgarh, Jharkhand, Manipur, Nagaland, Uttarakhand ,A&N Chhattisgarh, Jharkhand, Manipur, Nagaland, Uttarakhand ,A&N Islands)Islands)

WHAT IS DENDUE ?•Dengue is a viral disease

•It is transmitted by the infective bite of female Aedes Aegypti mosquito

•Man develops disease after 5-6 days of being bitten by an infective mosquito

•It occurs in two forms: Dengue Fever and Dengue Haemorrhagic Fever(DHF)

•Dengue Fever is a severe, flu-like illness (Influenza)

•Dengue Haemorrhagic Fever (DHF) is a more severe form of disease, which may cause death

•Person suspected of having dengue fever or DHF must see a doctor at once

There are actually four dengue clinical syndromes:

1.Undifferentiated fever;

2.Classic dengue fever;

3.Dengue hemorrhagic fever, or DHF; and

4.Dengue shock syndrome, or DSS.

Dengue shock syndrome is actually a severe form of DHF.

Dengue clinical syndrome

CLASSIS DENGUE Acute febrile illness with headache, retro-orbital Acute febrile illness with headache, retro-orbital

pain, myalgia, arthralgiapain, myalgia, arthralgia ““Break-bone fever”Break-bone fever” High fever 5-7 daysHigh fever 5-7 days Second fever for 1-2 days in 5% patients Second fever for 1-2 days in 5% patients Followed by marked fatigue days to weeksFollowed by marked fatigue days to weeks Classic dengue 15-60% of infectionsClassic dengue 15-60% of infections Nausea, vomiting, diarrhea (30%)Nausea, vomiting, diarrhea (30%) Macular or maculopapular rash (50%)Macular or maculopapular rash (50%) Respiratory symptoms: cough, sore throat (30%Respiratory symptoms: cough, sore throat (30%))

SIGNS & SYMPTOMS OF DENGUE FEVER

•Abrupt onset of high fever

•Severe frontal headache

•Pain behind the eyes which worsens with eye movement

•Muscle and joint pains

•Loss of sense of taste and appetite

•Measles-like rash over chest and upper limbs

•Nausea and vomiting

Dengue Hemorrhagic FeverWHO classification of DHF

Thrombocytopenia (platelet count <100,000)

Fever 2-7 days

Hemorrhagic manifestations with a positive tourniquet test Hemoconcentration or evidence of plasma leakage

Usually occurs in secondary infections after actively or passively (maternal) acquired immunity to a different viral serotype

Only 2-4% of secondary infections result in severe disease

Mortality is 10-20% if untreated, but decreases to <1% if adequately treated

Plasma leakage may progress to dengue shock syndrome

SIGNS & SYMPTOMS OF DENGUE HAEMORRHAGIC FEVER AND SHOCK SYNDROM • Symptoms similar to dengue fever

•Severe continuous stomach pains

•Skin becomes pale, cold or clammy

•Bleeding from nose, mouth & gums and skin rashes

•Frequent vomiting with or without blood

•Sleepiness and restlessness

•Patient feels thirsty and mouth becomes dry

•Rapid weak pulse

•Difficulty in breathing

AGENT FACTORS•The dengue viruses are the members of the genus flavivirus. These small (50nm)viruses contain single stranded RNA.

•There are four virus serotypes, which are designated as DEN-1, DEN-2, DEN-3 and DEN-4.

•Although all four serotypes are antigenicaly similar, they are different enough to elicit cross-protection only for a few months after infection by any one of them. Infection with any one serotype confers lifelong immunity to the virus serotype.

•Man and mosquito are reservoirs of infection. Transovarian transmission (infection carried over to next progeny of mosquitoes through eggs) has made the control more complicated.

•At present DEN1 and DEN2 serotypes are widespread in India

VECTOR OF DENGUE • Dengue is transmitted by the bite of female Aedes mosquito

• In India Ae. aegypti is the main vector in most urban areas; however, Ae albopictus is also found as vector in few areas of southern India.

• Female Aedes mosquito deposits eggs singly on damp surfaces just above the water line. Under optimal conditions the life cycle of aquatic stage of Ae. Aegypti (the time taken from hatching to adult emergence) can be as short as seven days• The eggs can survive one year without water. At low temperature, however, it may take several weeks to emerge. Ae. aegypti has an average adult survival of fifteen days. During the rainy season, when survival is longer, the risk of virus transmission is greater. It is a day time feeder and can fly up to a limited distance of 400 meters. To get one full blood meal the mosquito has to feed on several persons, infecting all of them.

TRANSMISSION CYCLE OF DENGUE

##There is evidence that vertical transmission of dengue virus from infected female mosquitoes to the next generation occurs through eggs, which is known as transovarian transmission.

1.The virus is inoculated into humans with the mosquito saliva.

2.The virus localizes and replicates in various target organs, for example, local lymph nodes and the liver.

3.The virus is then released from these tissues and spreads through the blood to infect white blood cells and other lymphatic tissues.

4.The virus is then released from these tissues and circulates in the blood.

5.The mosquito ingests blood containing the virus.

6.The virus replicates in the mosquito midgut, the ovaries, nerve tissue and fat body. It then escapes into the body cavity, and later infects the salivary glands.

7.The virus replicates in the salivary glands and when the mosquito bites another human, the cycle continues.

TRANSMISSION CYCLE OF DENGUE

Few common and favoured breeding places/sites of Ae. aegypti

LABORATORY DIAGNOSIS OF DENGUE

Haemagglutination inhibition (HI) test

Compliment Fixation Test (CFT)

Neutralization test (NT)

IgM-capture Enzyme-Linked Immunosorbent Assay (MAC-ELISA) ndvbcp recommended

IgG-ELISA

Rapid Diagnostic tests (NS 1)

Management of Dengue Fever (DF)• No specific therapy, management of Dengue fever is symptomatic and supportivei. Bed rest is advisable during the acute phase.ii. Use cold sponging to keep temperature below 39o C.iii. Antipyretics may be used to lower the body temperature. Aspirin/NSAID like Ibuprofen etc should be avoided since it may cause gastritis, vomiting, acidosis and platelet disfunction. Paracetamol is preferable in the doses as follows:

1-2 years: 60 -120 mg/doses 3-6 years: 120 mg/dose 7-12 years: 240 mg/doseAdult : 500mg/doseIn children the dose is calculated as per 10mg/KG Body Weight per dosewhich can be repeated at the interval of 6hrsiv. Oral fluid and electrolyte therapy are recommended for patients with excessive sweating or vomiting.v. Patients should be monitored in DHF endemic area until they become afebrile for one day without the use of antipyretics and after platelet and haematocrit determinations are stable, platelet count is >50,000/ cumm.

Vaccination

No current dengue vaccine Estimated availability in 5-10 years Vaccine development is problematic as the vaccine

must provide immunity to all 4 serotypes Lack of dengue animal model Live attenuated tetravalent vaccines under phase 2

trials New approaches include infectious clone DNA and

naked DNA vaccines

PreventionPreventionPersonal: clothing to reduce exposed skin insect repellent especially in early morning, late afternoon. Bed netting important mosquito repellants(pyrethroid based) coils, sanitation measuresEnvironmental: reduced vector breeding sites solid waste management public education empty water containers and cut weed/tall grass

PreventionBiological: Target larval stage of Aedes in large water storage

containers Larvivorous fish (Gambusia), endotoxin producing bacteria

(Bacillus), copepod crustaceans (mesocyclops) Chemical: Thermal fogging-malathion,pyrethrum Insecticide treatment of water containers Space spraying (thermal fogs) Indoor space spraying(2% pyrethrum), organophosphorus

compounds

Although the goal of disease control is to prevent epidemic transmission, if an epidemic does occur, ways to minimize its impact include:

•Teaching the medical community how to diagnose and manage dengue and dengue hemorrhagic fever (DHF), so they are better prepared to effectively manage and treat large numbers of cases. Mortality from DHF will thus be minimized.

•Implementing an emergency contingency plan to anticipate the logistical issues of hospitalizing large numbers of patients and to outline measures for community-wide vector control activities. Such plans should be prepared with the participation of all parties and agencies involved, and should be ready for implementation prior to the emergence of an epidemic.

•Educating the general public to encourage and enable them to carry out vector control in their homes and neighborhoods.

Social Issues

Public Health Major and escalating global public health problem

Global demographic changes: urbanization and population growth with substandard housing, water, and waster management systems

Deteriorating public health infrastructure with limited resources resulting in “crisis management” not prevention

Increased travel

Lack of effective mosquito control

Initiatives Strategic action plan Guidelines on clinical management 13 centers identified for Apex Referral laboratories for

diagnosis/treatment and surveillance ICMR Virus Unit, Kolkata. 137 sentinel surveillance hospitals amongst them in west bengal 1.Burdwan Medical College Hospital. 2. School of Tropical Medicine, Calcutta NIV Pune to supply ELISA kits Contingency grant made available IEC/BCC

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