Re-emergence of locally acquired Dengue Fever in Palm Beach County, Florida

1
Re-emergence of locally acquired Dengue Fever in
Palm Beach County, Florida

• Robert Parkes, MD Sandra Warren, MPH, JoEllen
  Alvarez, RN, MPH, Barbara Johnson, RN, BSN,
  Epidemiology Unit, Palm Beach County Health
  Department John Pellosie, JR.,D.O., MPH.,
  FAOCOPM, Chair, Department of Preventive
  Medicine, Nova Southeastern UniversityAlina
  Alonso, MD, Director, Palm Beach County Health
  Department

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Dengue Virus

• Single-stranded RNA flavivirus
• Arbovirus (Arthropod-Born) Vector mosquitoes
• Same virus family that causes West Nile fever,
  St. Louis encephalitis, yellow fever
• Causes dengue and dengue hemorrhagic fever

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Dengue Virus

• Four virus serotypes (DENV-1, 2, 3, 4)
• Provides specific life-time immunity for that
  serotype only
• Presence of a serotype may cause infection with a
  different serotype to be worse

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Common Dengue Vectors

• Aedes aegypti and Aedes albopictus

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Incubation / Viremic Periods

• Source CDC

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Dengue Fever

• Often mild, non-specific
• Sudden onset of high fever
• Severe headache
• Pain behind the eyes
• Body aches and joint pains
• Nausea or vomiting
• Rash

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Dengue Hemorrhagic Fever

• Severe abdominal pain
• Bleeding from the nose, mouth, and gums
• Frequent vomiting with or without blood
• Black stools
• Excessive thirst
• Pale, cold skin
• Restlessness or sleepiness

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Dengue Epidemiology

• Re-emerging infectious diseases in the world
• 50 to 100 million cases annually
• 500,000 hospitalizations
• 22,000 deaths (mostly children)
• Occurs in explosive epidemics

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Dengue World Distribution in 2008
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Dengue in the Americas1980 2009
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Dengue in USA

• During 1946--1980, no cases of dengue acquired in
  the continental United States were reported.
• Since 1980, a few locally acquired U.S. cases
  have been confirmed along the Texas-Mexico border
• Temporally associated with large outbreaks in
  neighboring Mexican cities

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Dengue in Florida

• Dengue previously endemic
• Increase in imported cases
• Warm climate, regular rainfall
• Abundant vectors

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Imported Dengue in Florida
1986 2008 Puerto Rico (41) Dominican Republic
(21) Haiti (13) 2011 Bahamas (9) Puerto
Rico (7) Haiti (3), Colombia (3), Trinidad (3)
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Vector Presence in Florida
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Dengue Fever in Key West, 2009

• September 1 - Monroe County Health Department
  notified of a New York resident diagnosed with
  dengue after travel to Key West
• Issued a press release to the public and notified
  area physicians of potential for local
  transmission of dengue
• Florida Keys Mosquito Control District
  implemented enhanced trapping and spraying of
  Aedes aegypti

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Number of locally acquired dengue cases (N 28),
by week of illness onset and method of
identification --- Key West, Florida, 2009--2010
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Locally acquired Dengue in FloridaCumulative
2011 Data as of 3 am, Dec 14, 2011
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Palm Beach County Dengue Cases 2005-2011
Acquired in FL Acquired in US, not FL Acquired outside of US
2005 0 0 3
2006 0 0 3
2007 0 0 5
2008 0 0 4
2009 0 0 1
2010 0 0 7
2011 2 0 9








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Purpose

• To present two cases of locally acquired dengue
  fever in Palm Beach County, Florida in 2011
• To highlight the need for continued surveillance

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Methods

• Case interviews and medical records review
• Confirmatory testing using enzyme-linked
  immunosorbent (ELISA) and real time polymerase
  chain reaction (PCR)/reverse transcriptase PCR
  (RT-PCR)

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Methods

• Transmission from recent imported cases and
  travel companions was assessed.
• Environmental evaluation
• Classified using the Dengue Fever case
  definitions for reportable diseases in Florida (1)

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Case Classification

• Confirmed a clinically compatible case that is
  laboratory confirmed

Test Days post onset Explanation Interpretation
Real time PCR 5days Patient viremic while febrile Confirmatory
IgM (paired specimens, acute and convalescent) 5days for acute gt5 days for convalescent Negative IgM in acute followed by a positive IgM in convalescent specimen Confirmatory
IgG (paired specimens,acute and convalescent) 5days for acute gt5 days for convalescent Must be a 4 fold increase in titer between acute and convalescent Confirmatory
IgM antibody in CSF   IgM antibodies demonstrated in cerebrospinal fluid Confirmatory
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Case Classification
Probable a clinically compatible case with
supportive serologic findings

• A positive IgM antibody test on a single acute
  (late)- or convalescent-phase serum specimen to
  one or more dengue virus

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Case Classification
Suspect a clinically compatible case with both
epidemiologic linkage criteria

• Travel to a dengue endemic country, OR
• Presence at a location with an ongoing outbreak
  within previous two weeks of dengue-like illness,
  OR
• Association in time and place with a confirmed or
  probable dengue case

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Results

• CASE 1
• On 9/30/2011, PBCHD received a positive lab for
  Dengue IgG
• 49 yr female, fever, sweating, fatigue
• DENV-1 positive by PCR/RT-PCR in acute serum
• IgG antibodies positive in acute and convalescent
  serum

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Results

• CASE 2
• On 10/3/2011, PBCHD received a positive lab for
  Dengue IgG
• 23 yr male, fever, chills, headache, fatigue and
  meningeal signs
• IgM and IgG antibodies positive in acute and
  convalescent serum
• Serological findings consistent with previous
  infection of dengue fever (3)

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Results

• Case 1 traveled to Haiti one month before onset
  of illness, outside incubation period (2)
• None of case 1 travel companions were sick
• Case 2 had no travel history outside Florida or
  the U.S.
• Secondary transmission ruled out from recently
  imported cases

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Results

• Environmental investigation Aedes albopictus
  for both cases.

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Conclusion

• Case 1- confirmed dengue fever
• Case 2- probable dengue fever
• Both acquired locally in Palm Beach County,
  Florida
• Both cases recovered

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Control efforts implemented

• County-wide mosquito advisory/alert were enacted
• Information and updates were provided
• Enhanced surveillance continued
• No new cases have occurred

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Conclusion

• It is essential to continue surveillance for
  Dengue Fever in Florida.

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References

• 1. Florida Department of Health Bureau of
  Epidemiology. Surveillance case definitions for
  Select reportable diseases in Florida. Retrieved
  February 15, 2012, from http//www.doh.state.fl.u
  s/disease_ctrl/epi/surv/CaseDefJan2010.pdf
•  
• 2. Heymann,D.L., (Ed.). (2008). Control of
  communicable diseases manual. Washington
  American Public Health Association.
• 3. Centers for Disease Control and Prevention.
  Dengue laboratory guidance and diagnostic
  testing. Retrieved February 15, 2012, from
  http//www.cdc.gov/dengue/clinicalLab/laboratory.h
  tml