Dengue Fever Information for Interning

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Dengue FeverInformation for Interning

• JoDee Summers
• Walden University

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What is Dengue?

• Arbovirus
• Flavivirus
• Mosquito borne (Aedes aegypti)
• Primarily a daytime feeder that lives around
  human habitation

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Virginia Bioinformatics Institute, 2006
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The Virus

• 4 serotypes
• DEN-1, DEN-2, DEN-3 and DEN-4
• Each serotype provides specific lifetime immunity
  and some possible short term cross immunity.
• Each serotype carries possibility of serious or
  life threatening disease, but some appear to be
  more virulent then others.

Centers for Disease Control and Prevention, 2009
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Clinical Syndromes

• Undifferentiated fever
• Most common manifestation
• Majority asymptomatic or mildly symptomatic
• Classic dengue fever
• Dengue hemorrhagic fever (DHF)
• Dengue shock syndrome (DSS)

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Dengue Hemorrhagic Fever

• 4 Criteria
• Fever, or recent history of acute
• Hemorrhagic manifestations
• Low platelet count (100,000/mm3 or less)
• Objective evidence of leaky capillaries

Pan American Health Organization, 1994
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4 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)

Centers for Disease Control and Prevention, 2009
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Dengue History

• 1779-1790 First reported epidemics in Asia,
  Africa, and North America.
• Post WWII Introduced to Southeast Asia. 
• 1950s Epidemic Dengue Hemorrhagic Fever in
  Southeast Asia.
• Currently Most countries in the world.

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World Health Organization, 2008
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Centers for Disease Control and Prevention, 2009
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World Health Organization, 2008
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Recent Activity

• Puerto Rico outbreak
• South Texas 2005
• Texas 1997 3 locally acquired
• Texas 1995 7 locally acquired
• The U.S. has the mosquito, but rarely see cases

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Diagnosis

• General Recommendations
• Epidemiologic considerations
• Season of year
• Travel history
• Important for assessment of symptomatic patients
  in non-endemic areas
• Determine whether the patient traveled to a
  dengue-endemic area
• Determine when the travel occurred
• If the patient developed fever more than 2 weeks
  after travel, eliminate dengue from the
  differential diagnosis

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Differential Diagnosis

• Influenza
• Measles
• Rubella
• Malaria
• Typhoid fever
• Leptospirosis
• Meningococcemia
• Rickettsial infections
• Bacterial sepsis
• Other viral hemorrhagic fevers

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Laboratory Tests

• Clinical laboratory tests
• CBCWBC, platelets, hematocrit
• Albumin
• Liver function tests
• Urinecheck for microscopic hematuria
• Dengue-specific tests
• Virus isolation
• Serology (IgM ELISA)

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Collection of Samples

• The tests for diagnosis are time dependent.
• Patient presents within 5 days of onset of
  symptoms draw blood immediately.
• A convalescent-phase sample should also be drawn.
  
• Patient presents 6 or more days after symptom
  onset the blood sample should be drawn as soon
  as possible. This sample should then be tested
  for serum IgM antibody.

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Treatment

• Fluids
• Rest
• Antipyretics (avoid aspirin and non-steroidal
  anti-inflammatory drugs)
• Monitor blood pressure, hematocrit, platelet
  count, level of consciousness
• Avoid invasive procedures when possible
• Unknown
• Patients in shock may require treatment in an
  intensive care unit

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Personal Prevention

• No vaccine
• Prevent mosquito breeding
• Eliminate standing water
• Fix window screens
• DEET or Picaridin

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Community Prevention

• Lessons for Future Dengue Prevention Programs
• Sustainable environmental control vs. eradication
  
• Community-based programs
• Promote the priority among health officials and
  general public

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Examples of What YOU Can Do!

• Involve the children!
• Interactive exhibits
• Public service announcements
• Television
• Radio
• Brochures

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Further Reading

• http//www.cdc.gov/dengue/educationTraining/index.
  html
• http//www.cdc.gov/dengue/about/inPuerto.html
• http//whqlibdoc.who.int/publications/2009/9789241
  547871_eng.pdf

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References

• World Health Organization (2008). Global alert
  and response. Impact of Dengue. Retrieved from
  http//www.who.int/csr/disease/dengue/impact/en/
• Centers for Disease Control and Prevention
  (2009). Dengue epidemiology. Retrieved from
  http//www.cdc.gov/dengue/epidemiology/index.html
• Virginia Bioinformatics Institute, (2006). Dengue
  transmission cycle. Retrieved from
  ci.vbi.vt.edu/pathinfo/pathogens/Dengue1.html
• Pan American Health Organization. (1994) Dengue
  and dengue hemorrhagic fever Guidelines for
  Prevention and Control. PAHO Washington, D.C.,
  1994 12.

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Questions??