Prevention and control of dengue fever
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Transcript of Prevention and control of dengue fever
Epidemiology, Prevention and Control of Dengue Fever
Dr. Gopalrao Jogdand, Ph.D. (U.S.A.)Professor & Head,
Car Medical College, Karim Nagar
Historical Background
• Dengue epidemics are known to have occurred over the last three centuries in tropical, sub tropical and temperate zones
• The first epidemic of dengue was recorded in 1635 in the French West Indies.
• Rush described about Break bone fever occurred in Philadelphia in 1780.
Continued….
• The first recorded outbreak of DHF occurred in Australia in 1897.
• Similar disease was found in Greece in 1928 and in Taiwan in 1931.
• First confirmed epidemic of DHF was recorded in Philippines in 1953-54
• Now prevalent in India, Indonesia, Myanmar, Sri lanka, New Caledonia, countries of western Pacific region.
Magnitude of the Problem
• There are 2.5 to 3 billion people are at the risk and living in epidemic prone areas globally
• South East Asia 100 million cases annually and 500,000 cases of DHF of which almost 90% are children
• The mortality rate is 5% causing 25,000 deaths annually
• Epidemics are cyclical
Continued….
• Africa----- 20 Endemic countries• Epidemics have been caused by all four
serotypes in the past 18 years• Recent major epidemics have been reported
in Comores and Eritrea• DHF not reported
Continued….
• Eastern Mediterranean– 4 endemic countries• Recent major epidemics in Diboti, Saudi
Arabia and Pakistan• Multiple serotypes are circulating• Sporadic cases of DHF documented
Continued….
• Western Pacific– 29 countries endemic• Recent major epidemics are reported I
Singapore, Cambodia, Vietnam, Philippines, Tahiti, Fiji and Palau
• All four serotypes circulating• DHF is a major public health problem and
disease is endemic in many countries
Continued….
• Americas– 42 Endemic Countries• Recent major epidemics in Central America,
Colombia, Peru, Venezuela, Brazil, Mexico, Cuba, Puerto Rico, Barbados and Trinidad
• All 4 serotypes are circulating• DHF is a newly emerging disease and now
occurs in 24 Countries
Continued….
• South East Asia– 7 Endemic countries• Recent major epidemics are reported from
India, Sri Lanka, Myanmar and Indonesia• All 4 serotypes are circulating• DHF is a major cause for hospitalization and
deaths of children
The Agent
• Dengue is caused by a virus member of the genus Flavivirus and family Flaviviridae.
• Virus is 50nm. in size and contains a single strand RNA.
• There are 4 serotypes of this virus DEN1, DEN2, DEN3 and DEN4
• There is a short lived cross immunity between these species
The Vector
• Globally Aedis aegypti is a important vector but has geographical limitation
• Other species are Aedis albopictus, A. Stegomyia, A. ploynesiensis, A. scutellaris and A. finalaya and in India A. tigris
• The most potent vector having epidemic potential is A. aegypti
Habits and habitat of the vector
• Vector: Aedis tigris mosquito in India, Aedis aegypti, stegomyia and albopictus in other countries.
• Habits of the vector: Clear water breeder, day time biter and domestic breeder
• Responsible for the transmission of Dengue fever, Dengue hemorrhagic fever and Dengue shock syndrome.
The Host
• Dengue virus infects humans and other lower primates
• Humans are main urban reservoirs of the disease
• Studies conducted in Africa and Malaysia show that monkeys are infected and can be reservoirs of the disease
Transmission Cycle
• Extrinsic incubation period: 8 to 10 days.• Intrinsic incubation period: 3 to 14 days an
average of 4 to 7 days.• Cyclic nature of the disease: In endemic
countries the cycle can be repeated at yearly interval.
• India is a endemic country for dengue fever.
Characteristics of the disease
• It is caused by a virus called flavi virus.• Virus gets access to human body by the bite of
a infected mosquito.• Causes three types of clinical manifestations:• Dengue Fever: High grade fever and joint pains.• DHF: dengue hemorrhagic fever causes
cutaneous hemorrhages and platelet depletion.
Continued….
• Dengue shock syndrome: Fever, cutaneous rash, GIT bleeding, severe bleeding, shock and multiple organ failure.
• Risk factors for dengue fever:• Immune status of the patient.• Infecting virus strain and its virulence.• Age of the patient.
Factors responsible for resurgence of Dengue
• Unprecedented population growth• Unplanned and uncontrolled urbanization• Increased distribution and vector density• Inadequate waste management and water
supply• Development of hyperendemicity• Inadequate health infrastructure
DHF as a serious Public Health Problem
• Seven out of ten countries have serious DHF problem
• DHF is a major cause for hospitalization and death of children in these countries
• Incidence of DHF has increased five times in the last 30 years beginning from 1980
• The geographic distribution has increased within countries and in other countries of the region.
Prevention & Control
• Elimination of breeding places of mosquito.• Avoidance of man------- mosquito----- virus
contact.• Drinking water storage containers are to be
drained at the interval of 3-4 days.• Proper cleaning of overhead water storage
tanks, never leave the tanks uncovered.
Continued….
• Coolers and desert coolers should be dried and then kept aside.
• Used tyres, bottles and containers should be disposed of properly.
• Personal protection:• Use of mosquito nets, repellant creams,
mosquito coils, mats and aerosols.
Continued….
• Medical measures:• Passive surveillance• Active surveillance• Early diagnosis and treatment of cases.• Integrated vector control and inter-sectoral
cooperation
Thank You