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.