climate change, introduced pests and vector-borne diseases
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Climate Change, Introduced Pests and Vector-Borne Diseases. Michael Niemela California Department of Public Health, Vector-Borne Disease Section. Overview. CDPH’s Vector-Borne Disease Section. What is Climate Change? Introduction to vector-borne d isease Dengue - PowerPoint PPT PresentationTRANSCRIPT
Climate Change, Introduced Pests and Vector-Borne
Diseases
Michael NiemelaCalifornia Department of
Public Health, Vector-Borne Disease Section
OverviewCDPH’s Vector-Borne Disease Section.
What is Climate Change?
Introduction to vector-borne disease
•Dengue
Introductions of Aedes albopictus to U.S. and CA.
Linking the preceding topics.
Vector-Borne Disease Section Offices
Sacramento HeadquartersSacramento Headquarters
Elk GroveElk Grove
OntarioOntario
Richmond LabRichmond Lab
Santa RosaCLOSED
Santa RosaCLOSED
ReddingRedding
6 4 Field Offices and Laboratory plus HQ in Sacramento
S.L.O.CLOSED
S.L.O.CLOSED Field Offices: 14
Lab: 4HQ: 5
VBDS' Function
The Vector-Borne Disease Section (VBDS) protects the health and well-being of Californians from diseases transmitted to people from insects and other animals.
VBDS Responsibilities and Activities
Develop and implement statewide vector-borne disease surveillance, prevention, and control programs.
Coordinate preparedness activities for detection and response to introduced vectors and vector-borne diseases, such as West Nile virus and the Aedes albopictus mosquito.
Conduct emergency vector control when disease outbreaks occur, 2010 Plumas Eureka State Park.
VBDS Responsibilities and Activities
Oversee the Vector Control Technician Certification and Continuing Education programs.
Provide information, training, and educational materials to governmental agencies and the public.
Oversee Special Local Need permits on
restricted use of public health pesticides.
Mosquito-Borne Diseases
West Nile virus
Western equine encephalomyelitis
St. Louis encephalitis
Malaria
Dengue
Yellow fever
Tick-borne diseasesLyme disease
Rocky Mountain spotted fever
Ehrlichiosis
Relapsing fever
Colorado tick fever
Babesiosis
Rodent-Borne DiseasesPlagueHantavirus cardiopulmonary syndromeRat bite feverLymphocytic choriomeningitis
Injurious and Nuisance Pests
Bed bugs
Body and head lice
Africanized honey bees
Red imported fire ants
Yellow jackets
Triatoma
Climate Change
What is Climate Change?
Climate change (a.k.a. global warming) is significant statistical, lasting change of weather over decades or longer spans of time.
•Local
•Global
Not from seasonal or single events.
Climate Forcings
Factors that can shape climate:
•Variations is solar radiation
•Deviations in the earth’s orbit
•Mountain building/continental drift
•Changes in greenhouse gas concentrations
Human Influences
Changes in the concentration of the key greenhouse gases carbon dioxide (a) and methane (b) since preindustrial times.
Sutherst R W Clin. Microbiol. Rev. 2004;17:136-173
Effects of Climate Change No So Simple to Predict…
Many confounding factors of human origin:– Land use patterns: urban, farming, land
cover – Rate of agricultural and industrial
development– water management– cultural and behavioral factors, etc.– civil unrest, war, famine
Positive feedback cycles: More X = more Y. More Y = more X.
Drivers of global change considered in relation to potential changes in the status of vector-borne diseases.
Sutherst R W Clin. Microbiol. Rev. 2004;17:136-173
Effects of Climate Change No So Simple to Predict…
Global effect not uniform: Detriment to some areas, a benefit to others.
Incomplete knowledge and few long-term studies.
Concurrent ecological cycles that are complex and vary between regions. •El Niño/La Niña, •Solar output
Global Temperature
Temperature Increase
U.K.’s Hadley Centre for Climate Change “Business as Usual Prediction”
NOAA’s Prediction
Mosquito-Borne Diseases
http://www.google.com/imgres?q=dengue&um=1&hl=en&safe=active&sa=N&rls=com.microsoft:en-us&biw=1680&bih=866&tbm=isch&tbnid=3PDoJlm517-70M:&imgrefurl=http://www.dengue-fever-symptoms.com/&docid=lM31_6PNhUNGvM&imgurl=http://www.dengue-fever-symptoms.com/images/dengue%252520fever%252520symptoms.gif&w=356&h=356&ei=p_wzT9iXJeWqiQKwkoW3Cg&zoom=1&iact=rc&dur=78&sig=113004992271279760932&page=1&tbnh=152&tbnw=163&start=0&ndsp=28&ved=1t:429,r:2,s:0&tx=123&ty=104
Dengue Virus
Arbovirus. Most common vector-borne virus.
Causes dengue fever (headache, fever, retro-orbital pain, rash, bleeding) and dengue hemorrhagic fever.
Four virus serotypes (DEN-1, 2, 3, 4)– Recovery from infection by one provides lifelong
immunity against that serotype– Confers only partial and transient protection
against subsequent infection by the other three– Evidence suggest that sequential infection
increases the risk of more serious disease resulting in DHF
Dengue Virus
DHF has become a leading cause of hospitalization and death among children in several countries.
No vaccine.
Incidence of dengue increasing world wide– 40% or 2.5 billion people globally are at risk for dengue
– Estimated 50-100 million infections annually worldwide• Up to a quarter of those are hemorrhagic fever (DHF)• 25,000 fatalities per year
Fever Cage
Dengue Vectors
Aedes albopictusAsian Tiger Mosquito
Aedes aegyptiYellow Fever Mosquito
Aedes albopictus/aegypti
Considered “domestic” mosquitoes.
Container breeders – difficult to eradicate.
Happily breed in tires, and very small containers, flower pot basins, cans, etc.
Sprinklers, improper water management.
Egg Rafts vs. Aedes Eggs
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Possible Larval Sources
Ae. Albopictus: Public Health Concerns
Vector: Dengue, chikungunya, and several other encephalitis viruses.
Responsible for recent outbreaks of dengue virus in south Florida, Texas, and Hawaii.
Vicious day-biting mosquito that prefers mammals.
Establishment would increase risk of introduction of new mosquito-borne viruses and pose a severe public health nuisance.
Native Distribution Ae. Albopictus
Current DistributionAe. albopictus
*as of 2007
Discovery in the USA
Houston, TX: Harris County Mosquito Control District discovered 1st breeding population in August 1985.
1986: Discovered in Louisiana, Tennessee, Mississippi, Missouri, Illinois, Ohio, Indiana, Arkansas, and Florida.
1987: Delaware, Kentucky, North Carolina, and Maryland.
C. Moore. 1999. JAMCA 15: 221-227
Distribution Aedes albopictus 1998
Aedes albopictus Introductions into California
Biology and behavior highly conducive to dispersal on cargo.
At least 6 separate introductions into California in the past 66 years.
Los Angeles 1946
Military cargo ship with 40 tons of salvaged tires from the Philippines.
Several contained water.
Larvae and adults were collected.
Oakland 1971
Cargo ship with 460 tons of surplus earthmoving equipment tires from Vietnam.
Several contained water. Larvae and pupae detected in one tire.
Tires unloaded in Los Angeles by U.S. Public Health Service quarantine officers.
Two additional tires with immatures detected.
Alameda County 1987
Alameda County MAD found one larva in large equipment tires shipped from Hawaii to a used tire dealer in Oakland.
No additional specimens were collected in subsequent years suggesting that the species failed to become established.
Los Angeles County 2001
Imported from southern China and Taiwan.
Shipped in 2-3 inches of water.
Containers held about 500 cases with 300 plants in each case.
“Lucky Bamboo” (Dracaena spp)
Federal Response
CDC press release July 2, 2001 implemented an embargo on importation of Dracaena shipments in standing water.
Notice of Embargo published in Federal Register (July 10, Vol. 66, No. 132).
Identified 15 infestations (6 counties) at nurseries
Orange County 2004
Orange County VCD received complaints of day-biting mosquitoes in late summer
Source: 20' boat shipped from Hawaii in July
Local Response
Comprehensive surveillance in and around infested areas.
Intensive mosquito control operations.
Door-to-door neighborhood inspections.
Public education.
El Monte. L.A. Co., 2011
September 2, 2011
Through October 4th, 2011
Through October 27th, 2011
What We Know or Don’t…
Mosquito DNA linked to China and not the Texas form. How did it get there?
Resident said she had been bitten for “several years”. What is the extent of the infestation?
Will winter have any effect on the population? Diapause.
Can we eradicate the infestation?
What Does Climate Change Have to Do With Bugs and
Disease?
The World is a Smaller Place
Air Travel
Shipping Routes
Locally Acquired Dengue not Hypothetical
2010: Key West, Florida: 28 cases. •5% randomly tested had antibodies or infection
2005: Brownsville, TX. 25 cases, 16 DHF.•Tamaulipas State: 1251 cases, 223 DHF•Previous 5 years, 541 cases, 20 DHF
2001: Hawaii. 153 cases linked to French Polynesia.
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Location and Count of Imported Dengue Cases in California 2010-2011
County CountSan Diego 12
Santa Clara 9
Orange 8
San Mateo 5
Los Angeles 3
Riverside 3
Solano 3
Climate Change, Disease and Vectors
Effects of Climate Change
Warmer Winters•Higher survival rates for vectors
Predicted to produce more extreme weather: Effects of Hurricane Katrina•Heavy Rains•Flooding
Displaced people particularly vulnerable to disease.
Biological Impacts
Warmer temperatures:
•Decreased generation time/gonotrophic cycles shorter
•Increased rate of biting
•Vectors remain active longer
•Virus becomes infective earlier and later into the season.
•Caveats to the above.
Introduced Vector Survival
Nature abhors a vacuum: As territory opens to them, vectors will move.
As temperature warms, vectors previously held in check by temperature will move north or will survive introduction.
Immunologically naïve populations will be exposed to novel disease agents.
Pesticides
Responding to Possible Climate Change
Long-term ecological and epidemiological research on
how environmental changes influence disease cycles
Enhanced surveillance
- Appearance of human cases in previously
disease-free areas
- Introduction of new vectors, hosts, or pathogens
- Changing transmission patterns in existing foci
Strengthen public health infrastructure to improve recognition and response
Responding to Possible Climate Change
Identify potentially vulnerable populations.
Maintain awareness of other changes that could
interact with climate changes to result in emerging
disease risks.
Measures to reduce the spread of disease or disease
vectors and hosts.
Review, evaluate and prepare countermeasures
(vaccines, therapeutic agents, insecticides, etc.).
SummaryVector-Borne Disease Section: Who we are and what we do.
Climate change and its potential effects.
Dengue virus.
Aedes albopictus introduction and consequences.
How climate change, disease and insects intersect.
Distribution Aedes aegypti