Dengue introduction


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Dengue introduction

  1. 1. Presented By: Madiha Shafiq Bs(Hons.), Final Semester
  2. 2. Presented By: Madiha Shafiq Bs (Hons.), Final Semester
  3. 3.  Endemic in more than 100 tropical and subtropical countries.  Several epidemics since 1980s.  Pandemic began in South East Asia after WW II with subsequent global spread.
  4. 4.  The word dengue is derived from African word Denga: meaning fever with hemorrhage .  Is caused by virus transmitted by bites of female Aedes mosquito.
  5. 5.  Dengue is a viral disease.  It is caused by infective bite of female Aedes aegypti.  Man develops disease after 5-6 days of being bitten by infective mosquito.  Dengue fever is a severe flu like illness.  Dengue Hemorrhagic fever (DHF) is more severe form of disease which can cause death.
  6. 6. 1.Causes dengue and dengue hemorrhagic fever 2. It is an arbovirus 3.Transmitted by mosquitoes 4.Composed of single-stranded RNA 5.Has 4 serotypes (DEN-1, 2, 3, 4)
  7. 7. The most common epidemic vector of dengue in the world is the Aedes aegypti mosquito. It can be identified by the white bands or scale patterns on its legs and thorax.
  8. 8. • Dengue transmitted by infected female mosquito  • Primarily a daytime feeder  • Lives around human habitation
  9. 9.  Clean and stagnant water collections  Breed mostly around human dwellings and surroundings  Lays eggs and produces larvae preferentially in artificial containers
  10. 10.  Aedes mosquitoes (Tiger mosquito): distinguished by white stripes on black body.  Important members Aedes family:A. aegypti, A.vittatus and A. albopictus.  They are most abundant during rainy season.  Lays egg singly, and eggs are cigar shaped.  Female mosquito acts as vector.  They do not fly over long distance- this factor facilitates its eradication.  It is a day biter
  11. 11. • Headache • Muscle and joint pain • Nausea/vomiting • Rash • Hemorrhagic manifestations • Fever
  12. 12.  High continuous fever lasting for 2-7 days.  Severe and continuous pain in abdomen  Bleeding from the nose, mouth and gums or skin bruising  Frequent vomiting with or without blood  Excessive thirst (dry mouth)  Pale, cold skin  Restlessness, or sleepiness
  13. 13.  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.
  14. 14.  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.
  15. 15.  In most tropical areas Ae. aegypti is highly urbanized.  They breed in fresh water like water stored for drinking or bathing and in rain water collected in any container like tires etc.  Dengue viruses have also been recovered from Aedes- Albopictus.
  16. 16.  Outbreaks in the Pacific area have been attributed to several other Aedes species.  These species breed in water trapped in vegetation
  17. 17.  Mosquito control or eradication programs require the simultaneous use of two approaches:  Reduction in breeding sites  Application of larvicides Alternatively, a significant reduction in population may be effected by closely spaced application of adulticides
  18. 18.  Source reduction campaigns should be well organized, supervised, and evaluated.  Includes proper disposal of discarded cans, bottles, tires, and other potential breeding sites not used for storage of drinking or bathing water.  Drinking and bathing water storage containers and flower vases should be emptied completely once weekly
  19. 19.  Most dengue cases are mild with flu like illness which can be treated and cured so no need to be panic.  Dengue id detected with Igm ELISA based test.
  20. 20.  There is no specific medicine to treat dengue infection.  To reduce pain use of pain relievers with acetaminophen and avoid medicines with aspirin, which could worsen bleeding.  Rest, drink plenty of fluids.  In case of Dengue Hemorrhagic fever hospitalization is a must. The mortality rate in the absence of hospitalization can be as high as 50%. With proper treatment the mortality comes down to 3%.  Vaccines are being developed against all 4 serotypes and they will definitely be the most effective way to prevent the disease.