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Dengue Fever Information for Interning. JoDee Summers Walden University. What is Dengue?. Arbovirus Flavivirus: Mosquito borne: ( Aedes aegypti ) Primarily a daytime feeder that lives around human habitation. Virginia Bioinformatics Institute, 2006. The Virus. 4 serotypes:
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Dengue FeverInformation for Interning JoDee Summers Walden University
What is Dengue? • Arbovirus • Flavivirus: • Mosquito borne: (Aedes aegypti) • Primarily a daytime feeder that lives around human habitation
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
Clinical Syndromes • Undifferentiated fever: • Most common manifestation • Majority asymptomatic or mildly symptomatic • Classic dengue fever • Dengue hemorrhagic fever (DHF) • Dengue shock syndrome (DSS)
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
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
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.
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
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
Differential Diagnosis • Influenza • Measles • Rubella • Malaria • Typhoid fever • Leptospirosis • Meningococcemia • Rickettsial infections • Bacterial sepsis • Other viral hemorrhagic fevers
Laboratory Tests • Clinical laboratory tests • CBC—WBC, platelets, hematocrit • Albumin • Liver function tests • Urine—check for microscopic hematuria • Dengue-specific tests • Virus isolation • Serology (IgM ELISA)
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.
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
Personal Prevention • No vaccine • Prevent mosquito breeding • Eliminate standing water • Fix window screens • DEET or Picaridin
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
Examples of What YOU Can Do! • Involve the children! • Interactive exhibits • Public service announcements • Television • Radio • Brochures
Further Reading • http://www.cdc.gov/dengue/educationTraining/index.html • http://www.cdc.gov/dengue/about/inPuerto.html • http://whqlibdoc.who.int/publications/2009/9789241547871_eng.pdf
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.