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									 Presented by : Kathi Rose Malloy, RN, BSN

Arboviral Diseases
   Information courtesy of:

       Department of Health and Human
     Service Centers for Disease Control and
Background: Arthropod-
borne Viruses (Arbovirus)
    Viruses spread via the bite of an arthropod,
     most commonly a tick or mosquito
    Approximately 80 arboviruses known to
     cause human disease
    In the Eastern region of the United States
     the two most important types of
     arboviruses include Eastern Equine
     Encephalitis (EEE) West Nile Virus (WNV)
Background : Eastern
Equine Encephalitis
   EEE first isolated in the US in 1933
   Most commonly found in North
    America, Central and South America,
    and the Carribean
   In the US, most cases reported from
    the eastern seaboard states, the Gulf
    Coast, and some inland midwestern
Background: West Nile
   West Nile virus was first recognized in
    the US in 1999 in metropolitan New
    York City
   More commonly found in Africa, West
    and Central Asia, and the Middle East
   It is unknown how the virus arrived in
    the US
EEE in the United States
 Spread of West Nile virus
 by state, 1999-2002.
West Nile Virus Activity in the U.S. in Birds, Horses,
Mosquitoes, Animals, or Humans.
West Nile Virus in the United States
as of October 15, 2003
Maryland's Arbovirus Surveillance
Testing Results 2003
(Updated 01/08/04)

 West Nile virus was established as
  endemic in Maryland in 2002.
  Therefore, the Maryland Department
  of Health and Mental Hygiene (DHMH)
  discontinued pickup and testing of
  dead birds in 2003.
Maryland's Arbovirus Surveillance
Testing Results 2003
(Updated 01/08/04)

 One-hundred and eighty (180)
  Maryland horses tested positive for
  West Nile Virus (WNV) infection in 20
  jurisdictions in 2003.
 Sixty-six (66) of the 180 horse cases
  were fatal.
Maryland Jurisdictions with
WNV in horses - 2003
Anne Arundel   16   Howard            8
Baltimore      6    Kent              4
Calvert        3    Montgomery        14
Caroline       10   Prince George’s   9
Carroll        40   Queen Anne’s      10
Cecil          2    St. Mary’s        7
Charles        8    Somerset          1
Dorchester     2    Talbot            7
Frederick      24   Washington        3
Harford        5    Worcester         1
Maryland's Arbovirus Surveillance
Testing Results 2003
(Updated 01/08/04)

 Over 195,000 mosquitoes were tested in
  Maryland between June 1 and October 31,
  2003. A total of 62 mosquito pools in 13
  jurisdictions tested positive for West Nile
  Virus during that time. One pool of Culiseta
  melanura mosquitoes collected in Worcester
  County tested positive for both WNV and
Maryland Jurisdictions with
WNV in mosquitoes - 2003
Alleghany      1    Frederick        3
Anne Arundel   10   Prince Georges   3
Baltimore Co   15   Somerset         3
Caroline       1    Talbot           1
Carroll        3    Wicomico         2
Charles        1    Worcester        11
Dorchester     5    Baltimore City   3
Maryland's Arbovirus Surveillance
Testing Results 2003
(Updated 01/08/04)

Seventy-three (73) human WNV cases
  (63 confirmed, 10 probable) have
  been reported this year in 13
Five (5) WNV – related fatalities have
  been reported to date.
Maryland Jurisdictions with
WNV in humans- 2003
Anne Arundel     7    Harford           2
Baltimore City   14   Howard            3
Baltimore Co     17   Montgomery        10
Caroline         1    Prince George’s   4
Carroll          2    Queen Anne’s      5
Charles          1    Washington        4
Frederick        3    Total             73
Eastern Equine Encephalitis
Surveillance in MD, 2003

   Mosquitoes - Ten (10) pools of Culiseta melanura
    mosquitoes in two jurisdictions (Wicomico and
    Worcester Counties) have tested positive for EEE in
    Maryland. A single pool of C. melanura mosquitoes
    collected in Worcester County tested positive for
    both WNV and EEE.
   Horses - Three horses in Worcester County have
    tested positive for EEE. All three were fatal cases.
    None of the horses had received the EEE vaccine.
   Ratites (Flightless birds) - One (1) emu in
    Wicomico County has tested positive for EEE.
Transmitting WNV
Additional Transmission
   Blood Transfusions
    – Additional evidence shows WNV can be spread via blood
    – CDC, FDA, HRSA, State and local Health Departments
      have ongoing investigations
    – A blood screening test has been developed
   Breast milk
    – Health benefits of breastfeeding are well established
    – Risk of WNV transmission via breast milk unknown
    – No suggested changes in breast feeding recommendations
Symptoms : EEE
   Most people have no symptoms
   Central Nervous system symptoms develop
    4-10 days after being bitten
   Sudden onset of fever, muscle aches,
   May progress to more severe symptoms
    such as seizure and coma (encephalitis)
   30 to 50% of patients with encephalitis die
    of the disease
Symptoms : West Nile
       Most people do not develop symptoms
       An estimated 20% become ill 3-15 days after
        being bitten
    –     Mild illness: fever, headache, body aches, and
          sometimes skin rash and swollen glands
       An estimated 1 in 150 persons infected develop a
        more severe form of the disease
    –     West Nile encephalitis: inflammation of the brain, high
          fever, stiff neck, stupor, disorientation, coma, tremors,
          convulsions, muscle weakness, and paralysis; few cases
          have been fatal
Geographic Risks
   People are only at risk when EEE and West
    Nile Viruses are circulating in nature
    – Northern states at risk during summer
    – Southern states at risk year round
   Maryland’s Eastern Shore is in a moderate
    climate and therefore at risk until the first
    “killing frost”
    – Killing frost is defined as 27-28° Fahrenheit for
      at least 4 hours
High Risk Persons
   Risk of arboviral encephalitis is higher for
    the youngest and oldest (50+) segments of
    the population
   People living in an area where the disease is
   People who work outside or participate in
    outdoor activities in areas where disease is
Human Illness

   EEE – fewer than 5 cases are reported
    in most years. Last human death in
    Maryland was in 1989 (Dorchester
   WNV – in the most affected areas of
    New York City only 2.6% population

   No specific therapy for infection of EEE
    or West Nile viruses
   Arboviral encephalitis treated by
    hospitalization, intravenous fluids,
    respiratory support, prevention of
    secondary infections, and good
    nursing care
    Not available for humans
    Horse vaccine is available –
     generally recommended
     annually in March, may
     booster mid-late summer in
     years where disease activity
  Prevention and Control
  – Apply insect repellent to exposed skin when
    outdoors. The most effective contain DEET.
    Higher concentrations equals longer protection.
    Over 50% does not increase length of
  – Use care in applying repellent to children: don’t
    put repellent on their hands and avoid their
    mouths and eyes. Products containing 10%
    DEET or less recommended for children 2-12.
  – When possible, wear protective clothing while
– Spray clothing with repellents
– Consider staying indoors between dusk and
  dawn to avoid peak mosquito biting time
– Avoid areas where mosquitoes are prevalent
– Fix or install window or door screens to keep
  mosquitoes out of buildings
    – Community based
    – Public Health Emergency
   EEE and West Nile encephalitis are NOT transmitted person to
   There is no evidence that a person can get the virus from
    handling live or dead infected birds. However, persons should
    avoid bare-handed contact when handling any dead animals
    and use gloves or double plastic bags to place the carcass in a
    garbage can.
   There is no evidence that the virus can be transmitted to
    humans through consuming infected birds or animals, but
    procedures for fully cooking meat should always be used.
   Although the vast majority of infections have been in birds;
    horses, and other mammals may be infected
   If you think you are infected and display any of the
    symptoms, contact your health care provider or doctor
Additional Info
Worcester County Health Department
Department of Health and Mental Hygiene –
  Disease control
Centers for Disease Control
Maryland Department of Agriculture
Reporting concerns

   Standing Water Reports – Worcester
    County Dept of Development @ 410-
   Mosquito Spraying – Worcester County
    Mosquito Control @ 410-632-3767
   Dead bird Disposal – State Health
    Topics Hotline @ 1-866-866-2769

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