Eastern Equine Encephalitis (EEE) in New Hampshire

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Eastern Equine Encephalitis (EEE)in New Hampshire

• Dianne Donovan, BSc
• Arboviral Surveillance Coordinator
• Ddonovan_at_dhhs.state.nh.us
• [phone]

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EEE Transmission Cycle
Mosquito vector
Bird reservoir hosts
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EEE History

• 1831 Horses in MA afflicted with an unknown
  encephalitis virus
• 1933-1935 Multiple equine outbreaks along the
  eastern seaboard
• 1938 1st human case in NE reported. MA 34
  human cases, 248 equine
• 1955-1959 MA reported 16 human cases NJ
  reported 33 human cases

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EEE
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NH Historical Perspective (EEE)

• 1973 75 equine deaths 12,000 pheasant deaths
• 1978 28 equine deaths
• 1980 1 human case reported (not confirmed), 1
  equine death
• 1982 1 equine death

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NH Historical Perspective (EEE)

• 2004 EEE detected in horses, birds, and
  mosquitoes
• 2005 Human cases
• - 7 reported human cases (2 died)
• - EEE detected in numerous non-human mammals,
  birds, and mosquitoes

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NH Historical Perspective (EEE)

• 2006 EEE detected in horse, birds, and
  mosquitoes
• 2007 3 reported human cases
• - EEE detected in mosquitoes, a horse, an
  alpaca

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EEE Symptoms Clinical Features
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EEE - Symptoms

• Incubation 4-10 days
• No symptoms in some people infected
• Severe symptoms in others
• - short prodrome, 5 days (fever, headache,
  abdominal distress)
• Progresses to disorientation, seizures, muscle
  weakness, paralysis, coma, death

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EEE - Clinical Features

• Common F (83), HA (75), N/V (61)
• lt 50 confusion, myalgia, abd pain
• lt 10 sore throat, diarrhea, CN palsies
• Imaging (CT, MRI) abnormal in two-thirds of
  patients

Source Deresiewicz NEJM 1997
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Laboratory Findings(severe neurological disease)

• Peripheral Blood
• Normal or elevated total leukocyte count
• Lymphocytopenia
• Anemia
• Hyponatremia

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Laboratory Findings(severe neurological disease)

• Cerebrospinal Fluid
• Pleocytosis (usually with a predominance of
  lymphoctyes)
• Elevated protein
• Normal glucose levels

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EEE - Diagnosis and Prognosis

• Diagnosis by IgM serum/CSF
• Confirmation by PRNT
• Mortality rate 35
• Neurological sequelae in 30 of survivors
• Lifetime expenses 3 million/case

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EEE Treatment

• There is NO specific treatment.
• Care of patients centers around supportive
  treatment of symptoms and complications.
• Vaccine only available for horses.

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NH EEE PATIENTSDemographic Clinical
Characteristics
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Demographic Clinical Characteristics

• Age Mean 40 years
• Range 4-80 years
• Gender 8 males 2 females
• Onset Date Earliest August 3
• Latest October 1

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Demographic Clinical Characteristics

• Prodromal Signs Symptoms
• Fever 9/10
• Weakness 9/10
• Fatigue 9/10
• Headache 8/10
• Myalgias 7/10
• N/V 7/10

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Demographic Clinical Characteristics

• Prodrome Duration (Days)
• Mean 7 days
• Range - lt1 to 15 days
• SEIZURES 4/10
• COMA 5/10 DEATHS 2/10

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Suspect Case Reporting
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Criteria for Report (a, b, or c)

• Any patient with viral encephalitis with
• - Fever gt 100 F
• - CNS involvement
• - Abnormal CSF profile suggesting a
• viral etiology
• Any patient with presumptive aseptic
• meningitis
• c. Guillain-Barre syndrome

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Criteria for Report

• Severe arboviral disease has occurred in patients
  of all ages.
• Consider patient travel history in off-season
  months. Year-round transmission is possible in
  some areas of the country.

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PREVENTION

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Personal Protection Works

• Wear long sleeves and pants in light colors to
  minimize the opportunities for mosquitoes to
  bite.
• Limit outside activity between evening and dawn
  when mosquitoes are most likely to bite.
• Consider using an effective insect repellent.

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Insect Repellents
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Mosquito Repellents CDC Recommendations

• DEET
• - Used for gt50 years, with millions of doses
  applied
• - Long-term safety established
• - In children American Academy of Pediatrics
  affirms use of DEET (up to 30) over 2 months of
  age

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Mosquito Repellents CDC Recommendations

• Picaridin
• - Used for years in Australia and Europe
• - Concentration available in US less
• - No serious toxicity reported
• Oil of Lemon Eucalyptus
• - plant derived compound
• - No serious toxicity reported
• - Recommended for children gt3 years

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The Bottom Line

• Repellent adverse reactions, when used
  appropriately are extremely rare
• EEE (and other mosquito-borne diseases) are
  definite, recognized threats to human health
• - Certain situations (risk factors for severe
  disease, outbreak situations) increase risk
• - Problems following arboviral neuroinvasive
  disease can be permanent

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Repellent Resources

• U.S. Environmental Protection Agency
• http//www.epa.gov/pesticides/health/mosquitoes/in
  sectrp.htm
• National Pesticide Information Center
• http//npic.orst.edu/wnv/

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The 2008 Season?
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2008 Season?

• Unable to forecast the exact level of risk
• NH communities with prior years EEE activity
  should consider mosquito-borne illness to be a
  human health risk for 2008

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Questions?