Transcript Vector Born Diseases Guest Speaker

Local Vector-borne Diseases &
Emerging Diseases of Concern
Carol Anne Hagele – Education Specialist
The District at a Glance
Independent special district formed in 1989 to
protect public health
Governed by a Board of Trustees
Funded through annual benefit assessment
currently (‘13-’14) assessment = $11.29 for
more than 90% of properties
Provide services to 23 cities and county areas
within the San Gabriel Valley
Integrated Vector Management
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Public Education and Outreach
Surveillance and Research
Mosquito Control
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Physical Control/Habitat Modification:
 Source reduction, exclusion, or site
design
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Biological:
 Predators, parasites, or pathogens
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Chemical:
 Larvicide or adulticide applications
Legal Action
 Abatement order
Tick-transmitted Disease
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Western Black-legged tick
Lyme Disease
Babesiosis
Ehrlichiosis
Rocky Mountain
Spotted Fever
Lyme Disease
Caused by spirochete: Borrelia burgdorferi
Initial Symptoms: 3-32 days
•Spreading bulls-eye rash
•Fever
•Headache
•Fatigue
Can lead to debilitating arthritis, joint pain,
weakness, cardiac & neurological complications
Lyme Disease
Other Tick-borne Diseases
Babesiosis
Babesia microti
•Fever
•Fatigue
•Jaundice
•Anemia
Primarily
transmitted by
nymphal ticks
Rocky Mountain Ehrlichiosis
Spotted Fever Ehrlichia sp.
Rickettsia rickettsia
•Moderate to high
fever
•Deep muscle pain
•Severe headache
•Rapidly spreading
rash on limbs
•Malaise
•Fever
•Headache
•Nausea
•Anorexia
Prevention
• Repellents containing
DEET
• Routine tick checks
• Promptly remove ticks
• Long sleeves, pants tuck into socks
Spring = Nymphs
Fall = Adults
Flea-borne Illness
• Plague and Typhus
bacteria carried by
rodent fleas
• Transmitted to
humans via flea bites
• Plague can also be
transmitted via cat
with pneumonic plague
or contact with body
fluids of infected
mammal
Symptoms
Typhus
Rickettsia typhi, R. felis
Transmitted by
defecating feeding
flea
• Headache
• Fever, chills
• Rash
• Rarely fatal
Plague
Yersinia pestis
Fever, chills, sore
throat, headache
Bubonic plague
lymphatic swelling
Septicemic plague
full body
involvement
Pneumonic plague life
threatening lung
involvement
Fatal if not treated
World Distribution of Plague
Plague Prevention
• Avoid heavily infested rodent areas
• Do not feed (live) or handle dead
rodents
• Use insect repellents
• Protect pets from fleas
• Don’t feed wildlife
Rodent-borne Diseases
Hantavirus
• Rodent transmitted
• Virus shed in urine,
feces, saliva of infected
deer mice (hantavirus)
• Avoid rodent infested
areas
• Air out enclosed spaces
and spray with 10%
chlorine solution prior
to clean up
Hantavirus
Hantavirus Outbreak
Curry Village, Yosemite National Park
The “Perfect Storm”
for Disease
•Environmental disturbance
•Loss of biodiversity
•Conditions favoring a
vector population “bloom”
•Increased Harborage
Mosquito-borne Diseases
Malaria distribution
Anopheles Mosquito
Plasmodium:
protozoan
parasite
Malaria in the U.S.
Emerging Diseases Includes “Old Friends” returning
1870: Malaria in the U.S.
Anopheles hermsi is
found here in the San
Gabriel Valley and is
the best vector of
malaria in the U.S.
Constant vigilance by
vector control experts
keeps this disease at
bay in the United
States.
Mosquito Control Matters
West Nile virus
Flavivirus
Reservoir Host
Insect Vector
Incidental Hosts
WNV in USA - 1999
WNV is USA - 2000
WNV in USA - 2001
WNV in USA - 2002
WNV in USA - 2003
WNV in USA - 2004
WNV in USA - 2005
WNV in USA - 2006
WNV in USA - 2007
WNV in USA - 2008
West Nile Virus
Health Information
West Nile Fever
80% exposed have no symptoms
If symptomatic: show within 3-15 days after bite
Moderate to high fever, headache, sore throat,
backache, muscle ache, joint pain, and fatigue
Long term exhaustion and muscle weakness common
West Nile Virus
Health Information
West Nile Neurologic Disease
•Swelling of the brain, spinal cord
•Profound muscle weakness, disorientation,
coma, paralysis, death
•Permanent, Polio-like, paralysis possible
Southern House Mosquito
Common domestic
pest - reaches
greatest numbers in
urban areas
Thrives in polluted
water habitats
Active from dusk to
dawn
Mosquito Larvae
Must have water for all juvenile stages
Immature stages can
be found in:
 rain-filled buckets
 trash cans
 old tires
 puddles
 neglected pools
 empty cans
Report green pools to the District!
What Drives WNV?
Mosquito populations surviving winter
Temperature: warm winter/early spring
Available habitat
Host bird populations
Immunity?
Disease Prevention
• Wear repellent
• No water, no mosquitoes
• Dump and/or report standing water
Biological and Biochemical
Control of Mosquitoes:
•Bacillus thuringiensis israelensis (Bti)
•Methoprene
•Wolbachia
Disease control for Dengue
Cytoplasmic incompatibility
Asian Tiger Mosquito
Aedes albopictus
• Daytime Biter
• New Diseases
• Likes
Backyards
Emerging Diseases
“Emerging" infectious diseases can be defined as infections that
have newly appeared in a population or have existed but are rapidly
increasing in incidence or geographic range. -Stephen Morse, PhD 1995
Underlying Factors Responsible for Emergence of Infectious Diseases
• Ecological changes
Agriculture; dams, changes in water ecosystems; deforestation;
climate changes, any increase in the human/animal interface
•Human demographics
Societal events: Population growth and migration, war, trends in
behavior (everything from how food is procured to sleeping
outside)
•International travel
Worldwide movement of goods
and commerce
Emerging Diseases
Underlying Factors Responsible for Emergence of Infectious Diseases
•Technology and Industry
Globalization of food supplies, food processing, transplant,
use of antibiotics
•Microbial
adaptation, change in
pathogenic profile
Selective mutations, resistance acquired through selection of
resistant strains
•Breakdown in public health measures
Reduction in prevention programs, inadequate sanitation
•Economy
Trends driven by economic downturn, e.g., changes in
nutrition, housing, etc
Pandemic Flu
Avian flu subtype
(high mortality)
+
Human flu subtype
(highly contagious)
=
PANDEMIC
STRAIN
Avian Influenza – H5N1, H7N9, H10N8
Avian Influenza (H5N1 only)
As of 2013 - Total
648 human cases
384 deaths (59%
fatality rate)
Compare to Malaria - Annually
Over 1.4 million human cases
Over 700,000 deaths
Avian Influenzas
Points to Consider
Current Avian Influenzas continue to
be a non-human disease
H5N1 and other strains are not
currently being consistently
transmitted from person to person
An influenza pandemic will occur sooner
or later – either a bird flu or a
seasonal flu strain
“Constant Vigilance!”
Arthropod-borne Diseases
of Concern
Dengue Fever and Dengue
Hemorrhagic Fever
Caused by Flavivirus of one of four closely
related, but distinct, virus serotypes
Case fatality rate 1% to 5%
“Bone-break Fever”
Victims of dengue
often experience
intense joint and
muscle pain
Aedes mosquito vector
The presence of Aedes
albopictus in San Gabriel Valley
creates the avenue for disease
Chikungunya
Transmitted by Aedes aegypti and Aedes
albopictus mosquitoes
Togavirus
Chikungunya in St. Martin, Caribbean
Rift Valley Fever
Mosquito-borne or direct contact with animals
Bunyavirus
Chagas Disease-Sylvatic Cycle
Which one will be next?
Have we learned anything from our
experience with West Nile virus?