Download Malaria in Loudoun County

Beware the Bug that Bites You:
Local Transmission of Malaria in
Loudoun County Virginia
Benita L. Boyer, RN, MS, CIC
District Epidemiologist,
Loudoun Health District
Leesburg, Virginia
November 4, 2003
Acknowledgements
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David Goodfriend & ALL
Loudoun County Health
Department employees
Loudoun Healthcare, Inc.
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Loudoun County Government
Services
Fairfax County Health
Department
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Dee Pettit, Mary Mismas, Kelly
Felkey
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Tina Lacey, Yvonne Richards,
Carol Garvey
Uniformed Services University
of Health Sciences
CDC Malaria Branch

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Lynn Frank
Montgomery County (MD)
Health Department
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John Marr, David Gaines,
Diane Woolard, Suzanne
Jenkins, Denise Sockwell
Hospitals B & C - ICPs
Maryland Department of
Health and Mental Hygiene

Antonio Pastor, Henry Rhee
Clarke Environmental Mosquito
Management
DCLS
VDH Office of Epidemiology

Gloria Addo-Ayensu, Happy
Callaway
Infectious Disease Physicians


Mobile Health Van, Lab, Linda
Belmonte (ICP)
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Louise Causer, John
MacArthur, Robert Wirtz,
Richard Steketee
Medical Analysis Systems, Inc.

Kirti Davé
Global Impact of Malaria
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One of the most common parasitic
infections in the world
Causes about 1 million deaths each year
New World species
Malaria in the United States
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Arrived in the U.S. through colonists/slaves
1914 - about 600,000 cases
1934 - decreased to 125,000 cases
Zucker. EID. vol 2, no 1, 1996
Malaria in the United States
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1950s - Officially eradicated in the U.S.
Since then - about 90 cases of
domestically acquired malaria
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Malaria-infected mosquitoes have been found
in NONE of these cases
There has been one other case in Virginia in
the past 50 years
Greater than 1,000 cases of imported
malaria diagnosed in the U.S. each year
Vectors
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Transmitted to humans
by Anopheline
mosquitoes
Most common species in
the eastern U.S.
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A quadrimaculatus
A. punctipennis
Humans are the animal
hosts for malaria
Anopheles quadrimaculatus
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Found in all 48 contiguous states
Larvae grow in:
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Feed at night
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permanent fresh water
slow streams, ponds, lakes containing
surface vegetation
after dusk/before dawn
Rest in hollow trees, underneath
buildings
Able to overwinter
Flight range less than one mile
Lay 9 -12 batches of eggs per lifetime

3000 eggs/batch
Mosquitoes of North America by
Stanley Carpenter and Walter
LaCasse
Virginia Mosquito Control
Association
Diagnosis and Treatment
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Diagnosis:
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mosquitoes
 Vectest™
 ELISA
 PCR
people
 blood smear
 PCR
 serology
Treatment:
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quinine
chloroquine
primaquine
Disease Control
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Modern decreases in
malaria cases are
attributed to:
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Draining of swamps
Access to medical care
Availability of quinine
and other anti-malarial
medications
Population movements
away from rural areas
Mosquito spraying
CDC
Malaria in Loudoun County
Loudoun County
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Suburb of Washington, DC
Population about 220,000
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Bordered by:
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with small but rapidly
growing Asian and Hispanic
populations
North - Potomac River and
Maryland
East - Fairfax County
West - West Virginia and Clarke
County
South - Fauquier and Prince
William Counties
Dulles International Airport
is located on the eastern
border of the county
Case #1
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August 23, 2002
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August 27, 2002
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Returned to Clinic A with no improvement
Fever of 103.5o F (39.7°C)
Dizziness and Nausea
Tachycardia
Anemic, with low white blood cell and platelet counts
Rx: Levofloxacin
Blood smear positive for Plasmodium vivax
Treatment:
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19 y.o. female from Cascades presented to Health Clinic A with
4-day history of fatigue, fevers, chills, myalgias, sinus pain
Dx: Sinus infection
Rx: Azithromycin
Started on chloroquine (3 days)
Switched to primaquine (14 days)
Outcome:
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Complete recovery
Case #2
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August 25, 2002
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15 y.o. male from Sugarland Run presented to Hospital A ER with
2 weeks of headaches, 4-day history of fever, nausea, vomiting,
malaise, nose bleeds
Fever of 105°F (40.6°C)
Tachycardia, splenomegaly, jaundice
Anemic, with low white blood cell and platelet counts
Blood smear positive for Plasmodium vivax
Treatment:
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Admitted to hospital
Clindamycin
Quinine
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Discontinued due to tinnitus
Switched to chloroquine (3 days)
Then primaquine (14 days)
Outcome:
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Complete recovery
Case #3
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March 16th,2003
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March 18th, 2003
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Admitted to hospital
Doxycycline
Quinine sulfate
Primaquine (14 days)
Outcome:
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Presented to Hospital C ER - no improvement
Fever of 102°F (38.9°C)
Anemic, with low white blood cell and platelet counts
Blood smear positive for Plasmodium vivax
Treatment:
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19 y.o. female from South Riding presented to Health Clinic B with
a 4 day history of fatigue, fevers, chills, severe headaches, malaise,
arthralgias, myalgias, nausea, vomiting, and mild abdominal pain
Prescribed an antibiotic for ‘sinus’ infection
Complete recovery
Note:
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Medical record listed patient’s risk factor for malaria as “lives in
Loudoun County”
Comparison of Symptoms
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Textbook Symptoms:
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Usually 10 -16 days
after infection
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Episodic high fever
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recurs every 2-3 days
Shaking chills
Sweating
Headaches, muscle
aches, malaise
Nausea, vomiting
Anemia and jaundice
May take up to one year
to present
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Case Symptoms:
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4 to 205 days before
presentation
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Fatigue
Episodic fever
Chills
Headaches, muscle
aches, malaise
Nausea, vomiting
Tachycardia
Anemia and jaundice
Sinus pain
Human Cases – Epidemiology
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Cases 1 & 2 lived
about 1 mile apart
in eastern Loudoun
County
Case 3 lived with a
family near case 2
until November
2002
Socialized after dusk
in the same area
with same group of
teens
Area is about 7
miles north of Dulles
International Airport
Montgomery County
Selden
Island
Epidemiology
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Several weeks prior to
becoming sick:
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they reported being outside
at night within a block of
each other
received multiple mosquito
bites each night
Cases 1 & 2 had no history
of foreign travel nor of
traveling anywhere else
together. Case 3 had a halfday trip to Mexico 2 years
prior, and travel to Western
Europe 4 years before onset
Case 3 also fished along the
Potomac west of her
residence and reported
‘many’ mosquito bites
Sugarland Run
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Sugarland Run has
a large diverse
immigrant
population
Many of the
houses had
screens that were
not intact
The area is close
to a regional park,
which contains
multiple potential
mosquito breeding
grounds
Sugarland Run
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A review of the
neighborhood found
multiple mosquito
breeding sites
Sugarland Run
Residents were educated
about the signs and
symptoms of malaria by
health department staff…
…through community town
hall meetings and houseto-house instructions prior
to adult mosquito spraying.
Traps
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Mosquito traps placed in
the area before spraying
caught up to 22
Anopheline mosquitoes
per trap
Traps placed after
spraying for a 1 mile
radius around the
suspected infection area
found 0 to 3 mosquitoes
per trap
None of the mosquitoes
tested positive for
malaria
Clarke Mosquito
Human Surveillance – Project 1
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No additional cases
of malaria were
found through:
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A review of patient
records at the two
local hospitals and
local urgent care
centers
Requests that
symptomatic
residents be
evaluated for
malaria by their
doctors and reported
immediately
Infected Mosquitoes
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On September 24, 2002 a mosquito trap was placed
in the Lansdowne community in response to
complaints of nuisance mosquitoes in an area with a
population at high risk for complications from West
Nile virus
Geography
Selden
Island
Montgomery County
Potomac River
Lansdowne is about 6 miles west of Sugarland Run
Mosquito Testing
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Four A. quadrimaculatus
and one A. punctipennis
mosquitoes were trapped
The A. quadrimaculatus
pool tested positive for
Plasmodium vivax by
VecTest™
There was insufficient
substrate left for DCLS to
confirm the VecTest
results by the more
traditional PCR testing.
VecTest™
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The VecTest malaria
assay has been on the
market since the
beginning of 2002
It was designed for the
military to be an
accurate, rapid test for
P. vivax and P.
falciparum antigens
It uses a rapid wicking
assay of monoclonal
antibodies to specific
peptide
circumsporozoites
Medical Analysis Systems, Inc.
Mosquito Testing
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In response to this
finding, additional
traps were placed
in the general area
On September 27,
a pool of three A.
quadrimaculatus
mosquitoes tested
positive for malaria
in Broad Run
Broad Run
Selden
Island
Montgomery County
Potomac River
Both mosquito pools were trapped within ¼ mile of
Montgomery County, Maryland.
Broad Run
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In response, Montgomery
County enlisted the aide
of mosquito surveillance
teams from the
Uniformed Services
University of the Health
Sciences (USUHS)
USUHS trapped
mosquitoes in
Montgomery County, MD
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along the Potomac River
on the mainland
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Selden Island
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Van Deventer Island
Selden and VanDeventer Islands
Montgomery County
Selden Island
Potomac River
Two mosquito pools on Selden Island tested positive for
malaria by PCR, as did one pool on VanDeventer Island
Selden Island
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Selden Island is part
of Montgomery
County, MD
It lies in the Potomac
River and:
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is less than 40 feet
from Virginia
is accessible only by
a bridge from
Loudoun County
is a popular fishing
and recreational
area
is privately owned
and used as a sod
farm.
Human Surveillance – Project 2
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31 permanent employees worked
on Selden Island over the summer
Countries of origin:
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USA: 13
South Africa: 1
Mexico: 17
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Central: 15
Hidalgo: 11
Guanquatro: 3
Distrito Federal: 1
Southeast: 1
Veracruz: 1
South: 1
Pachuca: 1
Workers reported being on the
island before dawn and after dusk,
and had multiple mosquito bites
All workers were screened for
malaria:
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Management at Company A’s
headquarters in southeast Loudoun
County
Workers in the sod fields near
Dulles Airport
Human Surveillance – Project 2
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No employee
reported feeling ill
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Communicable
Disease nurse from
Montgomery
County served as
interpreter &
administered
questionnaire
Blood smears drawn
on the employees all
negative
PCR and serology
results all negative
Fairfax County
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An additional mosquito
pool tested positive by
VecTest™ for malaria
near Herndon in Fairfax
County
This is the only positive
A. punctipennis pool
and is over 6 miles
away both from the
Potomac River and
where the adolescents
were infected
The significance of this
finding is unknown
Findings
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August 2002
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Between September and October 2002
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2 Loudoun County adolescents were symptomatic with P.
vivax malaria
5 traps along the Potomac River captured mosquitoes positive
for P. vivax by VecTest, some confirmed by ELISA, none by
PCR
The positive mosquito pools were located within 2 miles of
each other and at least 4 miles from the infected
adolescents
February 2003 a ‘malaria summit’ was held with all the
main players in attendance to review the findings and
discuss testing protocols
March 2003 a third domestically-acquired human case was
identified in a Loudoun County teenager
August 2003 mosquito surveillance along the Potomac
found a pool of A. punctipennis positive for P.vivax by
VecTest, and confirmed by ELISA and PCR.
What Does This Mean?
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The most likely explanation is that someone infected
with P. vivax abroad spent sufficient time on or near
Selden Island to infect the local mosquito population
In all previously reported outbreaks, no further cases
were reported in subsequent years
The VecTest results in 2002 were likely true positives
It is likely that mosquitoes infected with malaria have
existed along the Potomac River for some time
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There is likely no ongoing propagation of malaria
Each year the local mosquito population likely becomes
infected by people who contracted malaria abroad
The easier it is for people infected with malaria from their
original countries to receive treatment, the less likely they
will be able to re-introduce the infection into local
mosquito populations
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prior to WNV there was no reason to conduct mosquito surveillance
Social, immigration, and medical access issues
Airports receiving planes from endemic areas need to
diligently implement disinsection procedures.
Public Health Implications?
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Strategies to:
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Quickly detect
and treat human
cases
Remove
mosquito
breeding grounds
Ensure intact
window screens
Educate people to:
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Use insect
repellent
containing DEET
Wear light, long,
loose clothing