Mosquitoes, ticks, biting midges
5/1/2016
Mosquitoes,
Biting Midges,
and Ticks
Madness
• Eggs
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Larvae
Mosquitoes
Mosquitoes need water
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Four life stages
egg, larva, pupa, and adult
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Larval and pupal stages are aquatic
Two-winged Diptera (flies)
Family Culicidae: most species females have a
long proboscis for sucking blood
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Singly on surface or edge
of water
Eggs in rafts on surface
of water
Some sp. hatch 24-36 h
Some hatch after 1-3 y
Overwintering stage for
some species
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1st, 2nd, 3rd, 4th
instars
“Wigglers”, very
active, most come
to surface for air
4-12 d, some
species weeks
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Mosquitoes, ticks, biting midges
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Pupae
Stage that
changes from
larva to adult
“Tumblers”
very active,
come to
surface for air
3-6 d
Non-feeding stage
Adult mosquitoes emerge
from aquatic stages
5/1/2016
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(Male)
Adult (Females)
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Adult
Emerges first
Feeds on nectar
sources for energy
Mates within 2 -7 d
and dies
Emerge and feed on
nectar
Mates usually once
Needs blood meal to
develop eggs
1-5 blood meals over
life of
7 - 28 d
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Mosquitoes, ticks, biting midges
5/1/2016
Winter Survival Is Important:
Most overwinter in the egg stage
Some as larvae
Some as adults
Mated females rest in protected, cool locations
Warm spring days allow
females to seek a blood meal
Mosquitoes are classified based on larval
habitat
• Floodwater mosquitoes - Eggs laid
in damp areas
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Permanent water
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Containers
Flood Water Mosquitoes
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Aedes and Psorophora
Some genera are important pest species
Bite humans, livestock, pets
Can have very large populations
in spring and early summer
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Mosquitoes, ticks, biting midges
5/1/2016
Permanent Water Mosquitoes
Floodwater (cont.)
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Can survive in egg stage for several
years until flooded
Can have different hatches within
several days if increased
water levels hatch
new eggs
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Anopheles, some Culex spp.
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Quiet bodies of freshwater with sunlight,
surface vegetation and little wave action
Shallow edges of ponds, some lakes
backwaters of rivers slow moving
streams
Never in lakes
with wave action
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Adult populations peak in late April,
May, and June, some species hatch with
late summer fall rains
Adults die quickly during hot weather
Flood water usually dries up too fast to
support larvae in hot weather
Females most active around sunset or in
shady areas when disturbed
Some are active during the day
U.S. Mosquitos of Great Concern
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Culex tarsalis,
C. quinquefasciatus
(southern house mosquito)
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Note: all are permanent water mosquitoes,
populations peak in summer through fall at
same time virus activity peaks
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Feed on birds and mammals
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Vector WNV, WEE and SLE
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Mosquitoes, ticks, biting midges
5/1/2016
Culex quinquefasciatus
Culex tarsalis
Roadside ditches
Wastewater treatment
Culex spp. prefer nasty,
smelly water
Container Mosquitoes
(you breed ‘em, you feed ‘em)
Permanent Water Group (cont.)
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Populations low in spring
Build through the summer
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Peak July-October (varies by location)
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Many prefer birds
as hosts, feed on
mammals
Vectors of viruses
Bite more readily at night
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99% = Culex or Aedes
Larvae live in tree holes, rock pools even
leaf axils
Many associated with man made
containers
• Tires, cans, buckets, birdbaths, gutters, pet
water dishes, plant container bottoms that
catch water, even cans, paper cups etc.
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Mosquitoes, ticks, biting midges
5/1/2016
Typical Container Mosquito Habitat
Locations of
mosquito
surveillance
and Aedes
aegypti
presence in
Arizona 2015
Mosquito Hunting
Yellow fever mosquito
Asian tiger
mosquito
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Source Reduction
Eliminate
mosquito
breeding sites
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Mosquitoes, ticks, biting midges
Types of Larvacides
•Oils
•Suffocation – mechanical barrier
•Suffocation – oil entering the siphon blocking air
•Poisoning due to toxic properties of the volatiles
•Bacterial (Bti, B. sphaericus)
•Chemicals (organophosphate-
5/1/2016
Adulticides
Expensive and
relatively
ineffective
<60%
temephos, Abate®)
•IGR (growth hormones - methoprene)
•Fish, copepods, turtles
ULV hand fogger and portable mist blowers
•Organophoshates
•Pyrethroids/pyrethrum
•Portable mist blowers
•ULV
•Large droplet size
•Droplet size 10-46 microns
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Mosquitoes, ticks, biting midges
5/1/2016
Arboviruses in U.S.
30-50
Gambusia
affinis /
pool
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
Just focusing on mosquito vectored viruses
 Aedes
- Dengue fever, chikungunya, Zika
- West Nile, St. Louis, Western Equine, Eastern
Equine, Powassan, Unspecified California Serogroup
disease
 Culex
Live bearers– 75
young/female
New brood/6-8 weeks
Omnivorous
Mosquito Management
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Stop them at their source – larvacide
Kill vectoring adults – adulticide
Erect barriers against the ones you miss
Advocate personal
protection as the
final layer of
protection – repellents
Domestic virus vectoring in U.S.
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West Nile virus is the leading domestically
vectored arboviral disease each year
 Other arboviruses cause less significant
epidemics of neuroinvasive disease (symptoms
include meningitis,
encephalitis, and
acute flaccid
paralysis)
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Mosquitoes, ticks, biting midges
5/1/2016
Virus surveillance (human cases 2015 in
continental U.S.)
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Other modes of transmission
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West Nile (2060)
 St. Louis Encephalitis (19)
 Western Equine Encephalitis (0)
 Eastern Equine Encephalitis (5)
 Powassan Virus Disease (6)
 LaCrosse (48)
 Jamestown Canyon (6)?
Blood transfusion
 Organ transplantation
 Perinatal
 Breast feeding
 Sexual intercourse (Zika)
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Exotic viruses not yet considered endemic
(human cases 2015 in continental U.S.)
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West Nile (New York City 1999)
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Dengue local (211) imported (540)
 Chikungunya local (202) imported (673)
 Zika local (0) imported (2015 to date 358)
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 Pregnant:
31, Sexually transmitted: 7,
Guillain-Barré syndrome: 1
Local
transmission
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Mosquitoes, ticks, biting midges
West Nile
5/1/2016
West Nile Virus U.S. 1999-2002
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West Nile Fever
 Culex
spp.
transfusion, infected tissue donation, placental,
and accidental laboratory infections
 70-80% asymptomatic
 20-30% headache, body aches, joint pains, vomiting,
diarrhea, or rash - most people recover completely,
but fatigue can last for weeks or months
 <1% severely impacted by neurologic infection (10%
of whom die) symptoms include headache, high fever,
neck stiffness, disorientation, coma, tremors, seizures,
or paralysis
 Blood
West Nile 1999-2001
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2004
January
2004
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Mosquitoes, ticks, biting midges
5/1/2016
2007 WNV in the United States
2010 WNV in the United States
2007
2009 WNV in the United States
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2015 WNV in the United States
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Mosquitoes, ticks, biting midges
West Nile
5/1/2016
Chikungunya
1O vectors
Culex
Aedes
Human hosts
Incidental
1O host
% symptomatic
20-30%
72-97%
% chronic
<1%
30–40%
% fatality
<0.1%
0.03%
Symptoms
Fever, headache,
body aches, skin
rash, swollen
lymph nodes
Headache,
muscle pain,
joint swelling,
rash
1O
vectors
Human hosts
Dengue
Zika
Aedes
Aedes
1O host
1O host
% symptomatic 50-90%
% chronic
Variable
<0.1
% fatality
<1-50%(DF, DHF)
Very low GB
Headache, eye pain,
joint pain, muscle
and/or bone pain,
rash, nausea
Fever, rash,
joint pain, and
conjunctivitis,
microcephaly
Symptoms
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18%
Zika
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Low attack rate (18%), but high infection rate
(73%), based on 2007 Yap population
 Vector, interuterine, perinatal, lactation,
blood/organ, sexual transmission
 Mild symptoms
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Mosquito vectors
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Culex
 Can
fly significant
distances
 Breeding sites
relatively easy to
find and
remediate
 Night biter
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Aedes
 You breed ‘em – you
feed ‘em
 Cryptic breeding
sites difficult to find
and sometimes
impossible to
remediate
 Day biter
 Peridomestic
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Mosquitoes, ticks, biting midges
5/1/2016
Ae. aegypti female mosquito activity
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Loss – compensatory, incidental, punitive
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40 - 100 people die each year due to all
venomous stings
 43 (2011) – 286 (2012) people die due to
WNV
 712 (2011) – 5674 (2012)
total human clinical cases WNV
(51% neuroinvasive)
 Avoidable?
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You are
here
April 21 2016
What pest management experts can do to
protect their clients (and keep them out of court)
Litigation
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We have learned a great
deal from bed bug, honey
bee and fire ant litigation
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Injury, illness, death
 Ongoing reduction
in quality of life
 Medical costs
 Lost work revenue
 Incidental
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Sound (legally compliant) PMP mosquito specific service
contract
Trained licensed technicians
Insurance
QA/QC
Expert
Vector
control
district
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Mosquitoes, ticks, biting midges
5/1/2016
What pest management experts can do to protect
their clients (and keep them out of court)
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AZ 2016 Jan-April
http://azdhs.gov/preparedness/epidemiologydisease-control/mosquitoborne/index.php#dengue-info-data
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Clear promises clear expectations
Inspect, monitor, be informed
Log complaints (verified)
Respond immediately
No OTC or unauthorized
treatments
Be aware of
chemical
sensitivities
Document pesticide applications
Horribly unhelpful
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Zika
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1 travel case
ChikV
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2 travel cases
Dengue
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3 travel cases
WNF
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SLE
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1
RMSF
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Educational
Materials
Worst case
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Knowledge of problem,
but no action taken
Almost as bad
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No knowledge of problem because no one was looking
Never promise
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No-bugs, no-bites guarantee
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Impossible to achieve
Lots of things look the same as bug bites/stings
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Mosquitoes, ticks, biting midges
Common sense – just don’t get bitten
5/1/2016
General Life Cycle of a Tick
Ixodidae
Feed
Develop
Lay eggs
Hatch
Egg
Female
Larva
Male
Adults
Feed
Develop
molt
Nymph
Feed
Develop
molt
Use of trade names does not imply endorsement by UA, CDC or other agencies
Brown dog tick Rhipicephalus sanguineus DHG
Brown dog tick Rhipicephalus sanguineus (3000‐4000 eggs) 15
Mosquitoes, ticks, biting midges
5/1/2016
Brown dog ticks are “special”
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Heat tolerant ticks
Low desert tick activity year‐round
Reproduce indoors or outdoors in 63‐93 days
Widespread tick distribution (69%‐83% houses with dogs)
High tick densities in peridomestic environment
Close contact between humans, dogs and ticks Transport of ticks widespread due to stray dogs
Transmit RMSF very rapidly
Rhipicephalus sanguineus
When to Suspect Tick‐borne Illness
RMSF cases 2013
Acute febrile illness without apparent cause (fever, malaise, lethargy + other symptoms)
 Onset during May‐September (high tick activity)  History of tick bite or exposure
 Persons at risk for tick bite
 History of travel to endemic areas (US and global travel)
 Thrombocytopenia, elevated liver enzymes
 Rash not always a feature
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Mosquitoes, ticks, biting midges
Rocky Mountain Spotted Fever (RMSF)
• Disproportionately affects children and elderly
• Acute febrile illness with severe manifestations
• Typical symptoms include: fever, headache, nausea, vomiting, abdominal pain, and muscle pain
• A rash occurs 2‐5 days after fever, may be absent in some cases
5/1/2016
RMSF in Arizona
• Identified in tribal communities in eastern Arizona since 2003
• High infestations of brown dog ticks
• Many confirmed bites by nymphs (usually behind ears or back of neck)
When first investigated in AZ, the annual incidence of RMSF in this area was 300x that of rest of country
Rocky Mountain Spotted Fever (RMSF)
• Low incidence, high consequence disease
• High case fatality rate
• RMSF can be a severe or even fatal illness if not treated in the first few days of symptoms
• Doxycycline is most effective if started in the first 5 days of symptoms Mention of trade names does not imply endorsement by UA, CDC or other agencies.
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RMSF in Arizona
• Now seen in many widely separated tribal lands (over 400,000 persons at risk)
• From 2002‐2013, 321 cases were identified
 Case fatality rate = 7%
CDC, IHS and 2 tribes, estimate $13.2 million due to the epidemic of RMSF 2002 ‐ 2011, on two Indian reservations
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Mosquitoes, ticks, biting midges
RMSF in Arizona
• Dog serosurveys
• 3‐50% across six tribal lands (avg. 28.5%)
• Arizona, non‐tribal lands 5%
Biological Features
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5/1/2016
Biological Features
 Increased height of questing and human biting rate with elevated temperature (Melendez et al. 1995; Parola et al. 2008)
 Survives temperatures and humidities that other ticks cannot (Yoder et al. 2006a,b): 90% survival at 40°C and 33% survival at 50°C (122°F)
Personal Repellent Use
Ticks move among hosts during high tick activity (interrupted feeding)
• DEET (N, N‐diethyl‐3‐methylbenzamide)
Nocturnal detachment of nymphal and adult engorged ticks concentrates ticks and facilitates host contact
• Permethrin
– Use repellents containing 20‐30% DEET on exposed skin and clothing
– No greater than 15% for children
– Can only be used to treat clothing (0.5%)
• Other repellents registered by the EPA
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Mosquitoes, ticks, biting midges
5/1/2016
Avoid Contact with Ticks
• Clothing adjustment and access prevention measures (e.g., pants in sock, double‐stick tape, wear light colored clothing to see ticks)
• Avoidance of tick habitat or tick infested areas
Prevention
• Tumble clothes in a dryer on high heat for an hour
• Bathe or shower after coming indoors
• Examine gear, pets and each other
• Ask your doctor about antibiotics if bitten
• Learn the early signs of tick‐borne illness
• Routine tick check and removal
– Record date/save tick
• Prompt tick removal reduces risk
• Control ticks around your home Proper Tick Removal
Home Assessment‐ What Are We Looking For?
Examine for suitable microhabitats around
the home:
DO NOT: use petroleum jelly, a hot match, nail polish, or other products to remove a tick
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• Are animals (dogs especially) present?
• Are there access points to a crawl space?
• Is vegetation present providing shade and humidity?
• Are there wood piles, other debris?
• Furniture or outdoor garbage?
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Mosquitoes, ticks, biting midges
5/1/2016
Rhipicephalus sanguineus
Rhipicephalus sanguineus Infestation
Vegetation in surrounding areas increased moisture levels under houses on piers
“Shady places where dogs lie”
Rhipicephalus sanguineus
Infestation
Rhipicephalus sanguineus
Infestation
Voids in the concrete piers can contain ticks of all stages
Larvae and nymphs can quest from the surface
Applications: Proper use of pesticides; Proper timing and dosage of application; Maximize safety
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Indoors
Treatment of cracks and crevices (pyrethroids, desiccants)
 Do not treat food preparation areas
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Outdoors
Treatment of tick‐infested areas
Treatment of animal sleeping areas
 Do not treat ground water or areas where contaminated runoff could occur
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Treatment of Premises
• Outdoor
– Sprays
• Pyrethrins, Bifenthrin, Permethrin, Lambda‐
Cyhalothrin, Carbaryl
– Granules
• Carbaryl, Bifenthrin, Permethrin, Lambda‐
Cyhalothrin
– Dusts
• Carbaryl, Permethrin, Deltamethrin
Hose‐end sprayer for best results
Ticks detect and avoid pesticides, begin at the exterior, then work out and away from the house
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Mosquitoes, ticks, biting midges
Reminder: Dog Population Control
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Animal control Spay/neuter programs can stabilize the situation
Dogs get sick also
Topically Applied Products
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Pyrethrins
Permethrin, Permethrin + pyriproxyfen
Fipronil
Fipronil + methoprene
Fipronil + amitraz + methoprene
Metaflumizone + amitraz
Selamectin
5/1/2016
Collars
• Tetrachlorvinphos (Hartz Ultraguard)
• Tetrachlorvinphos + (S)‐methoprene (Hartz Ultraguard Plus)
• Propoxur (Zodiac, Breakaway Plus)
• Amitraz (Preventic)
• Amitraz + pyriproxifen (Preventic Plus)
• Deltamethrin (Adams Delta Force, Preventef‐D, Scalibor)
• Flumethrin + propoxur (Kiltix)
• Flumethrin + imidacloprid (Seresto)
Effectiveness reduced in high heat or if dog swims
Some products are highly toxic, use with caution especially when children interact with dogs
Useful Resources
• http://www.cdc.gov/rmsf/
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Mosquitoes, ticks, biting midges
5/1/2016
No‐see‐ums Culicoides or Leptoconops
(Ceratopogonidae)
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Summer month misery
Small <1/16th inch Painful bites
Pass through standard window screening
Culicoides feed early dusk and night Leptoconops during the day!
• Blood‐feeding female flies
• Eggs laid on moist surfaces or in water
• Not human disease vectors but allergic reactions are common
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