Dengue FeverInformation for Interning
JoDee SummersWalden 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:
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:
1. Fever, or recent history of acute2. Hemorrhagic manifestations 3. Low platelet count (100,000/mm3 or
less)4. 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.
World Health Organization, 2008
Centers for Disease Control and Prevention, 2009
World Health Organization, 2008
Recent ActivityPuerto Rico outbreakSouth Texas = 2005Texas 1997 = 3 locally acquiredTexas 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.