Dengue Prevention-

Occupational health

• By

• Dr.Ashok laddha

• Occupational Health • Occupational Health

Physician

History-1

• Dengue fever is also called break bone fever is mosquito

borne tropical disease caused by dengue virus

• The origins of the word dengue are not clear, but one theory

is that it is derived from the Swahili phrase "Ka-dinga pepo",

meaning "cramp-like seizure caused by an evil spirit".meaning "cramp-like seizure caused by an evil spirit".

• "dengue" meaning fastidious or careful

• in the West Indies who contracted dengue were said to have

the posture and gait of a dandy, and the disease was known

as "Dandy Fever".

History-2

• The first record of a case of probable dengue fever is in a

Chinese medical encyclopedia from the Jin Dynasty (265–420

AD) which referred to a “water poison” associated with flying

insects.

• The first recognized Dengue epidemics occurred almost• The first recognized Dengue epidemics occurred almost

simultaneously in Asia, Africa, and North America in the

1780s, shortly after the identification and naming of the

disease in 1779

• The first confirmed case report dates from 1789 and is by

Benjamin Rush, who coined the term "breakbone fever"

because of the symptoms of myalgia and arthralgia.

History-3

• The viral etiology and the transmission by mosquitoes were

only deciphered in the 20th century.

• The socioeconomic impact of World War II resulted in

increased spread globally

• about 2.5 billion people, or 40% of the world’s population,• about 2.5 billion people, or 40% of the world’s population,

live in areas where there is a risk of dengue transmission• The World Health Organization (WHO) estimates that 50 to

100 million infections occur yearly, including 500,000 DHF

cases and 22,000 deaths, mostly among children.

Indian scenario-1

• The annual number of dengue fever cases in India is nearly

300 times higher than officially reported

• India had nearly 6m annual clinically diagnosed dengue cases

between 2006 and 2012 .

• India is believed to have more cases of dengue than any other • India is believed to have more cases of dengue than any other

country,

• costs the emerging economic power at least $1.1bn (£700m)

each year in medical and other expenses.

• The first isolation of dengue in India occurred in Calcutta, now

Kolkata, in 1945,

• the first epidemics in India were reported in the 1960s.

Indian scenario-2

• Tamil Nadu recorded more than one fourth of all dengue

cases and deaths in the country the state recorded 9,249

dengue cases

• the number of cases tested positive has gone up by 267%. The

country recorded 35,066 dengue cases and 216 deathscountry recorded 35,066 dengue cases and 216 deaths

• India accounts for nearly one-third of all dengue cases

reported globally,

Possible factors for dengue fever

spread

• Unplanned urban overpopulation of areas leading to inadequate

housing and public health systems (water, sewerage and waste

management)

• Poor vector control, e.g., stagnant pools of water for mosquito

breeding

• Climate change and viral evolution (increased virus transmission has

been linked to El Nino conditions)

• Increased international travel (recreational, business or military) to

endemic areas

• Unplanned urbanization is believed to have had the largest impact

on disease amplification in individual countries, whereas travel is

believed to have had the largest impact on global spread.

Risk Factors-2

• Living or traveling in tropical areas. Being intropical and subtropical areas increases your riskof exposure to the virus that causes dengue fever.Especially high-risk areas are Southeast Asia, thewestern Pacific islands, Latin America and thewestern Pacific islands, Latin America and theCaribbean.

• Prior infection with a dengue fever

virus. Previous infection with a dengue fever virusincreases your risk of having severe symptoms ifyou're infected again.

Dengue fever definition-1997-WHO

• Dengue fever is most commonly an acute febrileillness defined by the presence of fever and twoor more of the following, retro-orbital or ocularpain, headache, rash, myalgia, arthralgia,leukopenia, or hemorrhagic manifestations (e.g.,positive tourniquet test, petechiae;leukopenia, or hemorrhagic manifestations (e.g.,positive tourniquet test, petechiae;purpura/ecchymosis; epistaxis; gum bleeding;blood in vomitus, urine, or stool; or vaginalbleeding) but not meeting the case definition ofdengue hemorrhagic fever. Anorexia, nausea,abdominal pain, and persistent vomiting may alsooccur but are not case-defining criteria for DF.

New-Dengue fever definition-2009-

WHO

• Fever and two of the following:

• Nausea, vomiting

• Rash

• Aches and pains• Aches and pains

• Leukopenia

• Positive tourniquet test

Severe dengue Definition

• Severe dengue is defined by one or more of

the following:

• (i) plasma leakage that may lead to shock

(dengue shock) and/or fluid accumulation, (dengue shock) and/or fluid accumulation,

with or without respiratory distress, and/or

• (ii) severe bleeding, and/or

• (iii) severe organ impairment

Criteria for Severe Dengue

• Severe plasma leakage

• leading to:

• Shock (DSS)

• Fluid accumulation with respiratory

• distress• distress

• Severe bleeding as evaluated by clinician

• Severe organ involvement

• Liver: AST or ALT >=1000

• CNS: Impaired consciousness

• Heart and other organs

Dengue Facts

• The mosquito is attracted by:

• Body odours

• Carbon di-oxide and heat emitted from

animals or humansanimals or humans

• Ades are day biters—most active during dwan

and dusk

Etiological agent

• Etiological agent

– Dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) -

flaviviruses

• Principal vector• Principal vector

– Aedes albopictus

– Aedes aegypti

Mode of Transmission

Infected

mosquito

Healthy personInfected person

Incubation Period: 3 to 14 days

Most commonly 4 to 7 days

Dengue fever is not spread by contact with

infected persons.

symptoms

complications of dengue fever

• The complications of dengue fever are usually associated with themore severe forms of dengue fever, hemorrhagic and shocksyndrome. The most serious complications, although infrequent,are as follows:

• Dehydration

• bleeding (hemorrhage);

• low platelets;• low platelets;

• hypotension;

• bradycardia;

• liver damage;

• neurological damage (seizures,encephalitis);Cardiomyopathy

• and death.

Greatest risky tropical areas

• The Indian subcontinent

• Southeast Asia

• Southern China

• Taiwan

The Pacific Islands• The Pacific Islands

• The Caribbean (except Cuba and the Cayman Islands)

• Mexico

• Africa

• Central and South America (except Chile, Paraguay, and Argentina)

Occupation -Risk Group

• Agriculture workers

• Construction workers

• Travelers

• Sewerage workers• Sewerage workers

Diagnosis

• Clinical and physical examination BY THE GOOD CLINICIAN can clinch the Diagnosis.+ Lab.tests:

• Isolation of virus

• Antigen Detection

• MCA-ELISA• MCA-ELISA

• CBC,Blood sugar,Renal Function test,

• Liver Function test

• PCR

• Antibody titer for dengue virus type

• Other tests like cardiac enzymes/ecg

Complete Blood Count

• Both the experts highlighted low platelet

count as an important factor in dengue

diagnosis. ‘A complete blood count (CBC) is of

significant importance for clinical diagnosis ofsignificant importance for clinical diagnosis of

dengue. If a patient has high fever and is

found to have a low platelet count, dengue is

suspected’, Normal platelet count in a healthy

individual is about 2.5 lakh cells/cubic mm.

ELISA test for dengue NS1 Ag

• Viruses have the tendency to attack platelets anddestroy them, thereby lowering the plateletcount. ‘But, a low platelet count does not alwaysmean that you are suffering from dengue. Yourplatelet count can be lowered in any kind of viralinfection. That the reason why we need moreplatelet count can be lowered in any kind of viralinfection. That the reason why we need morespecific tests to confirm dengue. ELISA NS1Antigen test is a specific test for detecting denguevirus antigen. But this test may show negativeresults in the early stages of the disease. So thetest needs to be repeated on the 2nd ,3rd or4th day for confirmatory results,’

PCR for detecting viral DNA

• Detection of NS1 during the early phase of a

primary infection may be greater than 90%

but for subsequent infections it is only 60–

80%. So, PCR and viral detection test is80%. So, PCR and viral detection test is

considered. This test is more reliable in the

first 7 days of infection, when NS1 Ag test may

be negative despite infection,’

Serum IgG and IgM test

• Serum antibody tests are useful for confirming

a diagnosis in the later stages of the infection,’

Once the virus gains entry into the body, the

immune cells begin to produce antibodies IgGimmune cells begin to produce antibodies IgG

and IgM against the virus. The level of these

antibodies increases gradually and remains

high for a really long time. So it is also a useful

indicator of a previous infection.

Management

• No specific antiviral treatment available

• No vaccines available

• Supportive treatment

• Bed Rest

• Fluid Replacement• Fluid Replacement

• Platelet Transfusion (As per PT protocol) in severe casesshould be given to patients with severethrombocytopenia (<10,000/mm3) and activebleeding.

• Blood transfusion should be given to patients with significant bleeding

Food-Increase Platelet count

• Green leafy vegetables

• Omega-3 fatty acids

• Vitamin C

• Papaya leaves• Papaya leaves

• Pomegranate

Vaccination

• There are currently no licensed dengue

vaccines available. Several vaccine candidates

are in clinical or pre-clinical development. The

most advanced candidate, a chimericmost advanced candidate, a chimeric

tetravalent vaccine based on the yellow fever

17d backbone, is currently under evaluation in

Phase III clinical trials.

Prevention—Integrated vector control

program

• Advocacy, social mobilization and legislation toensure that public health bodies andcommunities are strengthened;

• Collaboration between the health and othersectors (public and private);sectors (public and private);

• An integrated approach to disease control tomaximize use of resources;

• Evidence-based decision making to ensure anyinterventions are targeted appropriately; and

• Capacity-building to ensure an adequateresponse to the local situation.

Prevention

• Vector control is implemented using environmental management and chemical methods.

• Proper solid waste disposal,

• elimination of stagnant water in domestic environment and improved water storage practices.

• Aerosol and liquid spray has to be applied directly to the adult mosquito for effective killing, e.g. household pesticides.

• Aerosol and liquid spray has to be applied directly to the adult mosquito for effective killing, e.g. household pesticides.

• Mosquito coil and electric mosquito mat/ liquid has to be placed near possible entrance, such as window, for mosquito.

• Wear long-sleeved clothes and long trousers when going outdoors. Bodies could be protected from mosquito bite by applying insect repellent (containing DEET) on the clothes and exposed part of the body especially when you travel to Dengue Fever endemic areas.

• Mosquito bed net could be used when the room is not air-conditioned.

Five step prevention

• 1.Change water in vases and bowls on

alternate days

• 2.Remove water from flower pot plates on

alternate daysalternate days

• 3.Turn over all water storage containers

• 4.Cover bamboo pole holders when not in use

• 5.Clear blockages and put BTI insecticide in

roof gutters monthly

WHO’s dengue control strategy

• In the absence of a licensed vaccine, WHO recommends :

• prevention of dengue through vector control methods such as mosquito habitat removal and use of insecticides. use of insecticides.

• Integrated vector control,

• surveillance,

• case management,

• and future vaccines

emergency response plans

• Establishing a multi-sectoral dengue action committee.

• Formalizing an emergency action plan.

• Enhancing disease surveillance.

• Diagnostic laboratory testing.

• Enhancing vector surveillance and control.

• Protecting special populations.• Protecting special populations.

• Ensuring appropriate patient care.

• Surveillance, emergency preparedness and response

• Educating the community and relevant professional groups

• (local, provincial and national governments, as appropriate) as well as their roles and responsibilities in dengue prevention and control.

• Investigating the epidemic.

• Managing the mass media

Take home message

• Prevention is better than cure

• cause

• 'small creatures, big

threat'.

Lastly………

• Maintain personal hygiene

• Maintain environmental hygiene

• create awareness about methods to prevent

vector-borne diseases,vector-borne diseases,

• Provision of safe drinking water

• Proper management of sewage and drainage