Mosquitoes, ticks, biting midges
2/29/2016
Mosquitoes,
Biting Midges,
and Ticks
Madness
Mosquitoes can breed in……..
A.
B.
C.
Brown dog ticks
A.
B.
C.
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•
DHG
3%
A.
B.
C.
Four life stages
egg, larva, pupa, and adult
94%
Larval and pupal stages are aquatic
Two-winged Diptera (flies)
Family Culicidae: most species females have a
long proboscis for sucking blood
3%
B.
C.
• Eggs
•
3%
Mosquitoes need water
A.
•
94%
Mosquitoes
Are intolerant to
high temperatures
Are relatively heat
tolerant
Prefer room
temperature
3%
•
Natural water
catchments, and manmade containers, but
not in irrigated lawns
In man-made
containers holding
more than 1 pint of
water
Natural water
catchments, man-made
containers, and
irrigated lawn areas,
but not maintained
swimming-pools
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
Larvae
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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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2/29/2016
Pupae
Stage that
changes from
larva to adult
“Tumblers”
very active,
come to
surface for air
3-6 d
Non-feeding stage
Adult (Male)
Emerges first
Feeds on nectar
sources for energy
Mates within 2 -7 d
and dies
Adult mosquitoes emerge
from aquatic stages
Adult (Females)
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•
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•
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
DHG
Emerge and feed on
nectar
Mates usually once
Needs blood meal to
develop eggs
1-5 blood meals over
life of
7 - 28 d
Mosquitoes are classified based on larval
habitat
• Floodwater mosquitoes - Eggs laid
in damp areas
•
Permanent water
•
Containers
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Mosquitoes, ticks, biting midges
2/29/2016
Flood Water Mosquitoes
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Floodwater (cont.)
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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Permanent Water Mosquitoes
•
Anopheles, some Culex spp.
•
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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•
DHG
Aedes and Psorophora
Some genera are important pest species
Bite humans, livestock, pets
Can have very large populations
in spring and early summer
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
•
Culex tarsalis,
C. quinquefasciatus
(southern house mosquito)
•
Note: all are permanent water mosquitoes,
populations peak in summer through fall at
same time virus activity peaks
•
Feed on birds and mammals
•
Vector WNV, WEE and SLE
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Mosquitoes, ticks, biting midges
2/29/2016
Permanent Water Group (cont.)
Culex quinquefasciatus
•
Populations low in spring
Build through the summer
•
Peak July-October (varies by location)
•
Many prefer birds
as hosts, feed on
mammals
Vectors of viruses
Bite more readily at night
•
Culex tarsalis
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•
Container Mosquitoes
(you breed ‘em, you feed ‘em)
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Roadside ditches
Wastewater treatment
Culex spp. prefer nasty,
smelly water
Typical Container Mosquito Habitat
DHG
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.
Mosquito Hunting
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Mosquitoes, ticks, biting midges
Locations of
mosquito
surveillance
and Aedes
aegypti
presence in
Arizona 2015
2/29/2016
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Source Reduction
Eliminate
mosquito
breeding sites
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 (organophosphatetemephos, Abate®)
•IGR (growth hormones - methoprene)
•Fish, copepods, turtles
Adulticides
Expensive and
relatively
ineffective
<60%
ULV hand fogger and portable mist blowers
•Organophoshates
•Pyrethroids/pyrethrum
•Portable mist blowers
•ULV
•Large droplet size
•Droplet size 10-46 microns
DHG
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Mosquitoes, ticks, biting midges
2/29/2016
Mosquito Management
30-50
Gambusia
affinis /
pool
•
•
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Live bearers– 75
young/female
New brood/6-8 weeks
Omnivorous
WEST NILE
CHIKUNGUNYA
• Virus
•
Flavivirus
•
Alphavirus
• 1O vectors
•
Culex
•
Aedes
• Human hosts
•
Incidental
•
1O host
• % symptomatic
•
<20%
•
72-97%
• % chronic
•
<1%
•
30–40%
• % fatality
•
<1%
•
0.03%
• Symptoms
•
fever, headache, body
aches, skin rash, and
swollen lymph nodes
•
headache, muscle
pain, joint swelling,
rash
Educational
Materials
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
• Virus
•
• 1O vectors
•
• Human hosts
DENGUE
Flavivirus 1-4
ZIKA
•
Flavivirus
Aedes
•
Aedes
•
1o host
•
1o host
• % symptomatic
•
Can be 50%
•
<20%
• % chronic
•
Variable
•
?
• % fatality
•
<1-50% (DF,DHF)
•
Very low GB
• Symptoms
•
Headache, eye pain,
joint pain, muscle
and/or bone pain,
rash, nausea
•
fever, rash, joint
pain, and
conjunctivitis
(?microcephaly?)
CDC
http://www.cdc.gov/features/stopmosquitoes/
USGS
http://diseasemaps.usgs.gov/dep_ga_human.html
DHG
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Mosquitoes, ticks, biting midges
2/29/2016
Brown dog tick Rhipicephalus sanguineus General Life Cycle of a Tick
Ixodidae
Feed
Develop
Lay eggs
Hatch
Egg
Female
Larva
Male
Adults
Brown dog tick Rhipicephalus sanguineus (3000‐4000 eggs) Feed
Develop
molt
Nymph
Feed
Develop
molt
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 Potential for transport of ticks across widespread area due to stray dogs
Transmit RMSF very rapidly
Rhipicephalus sanguineus
When to Suspect Tick‐borne Illness
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

DHG
7
Mosquitoes, ticks, biting midges
RMSF cases 2013
2/29/2016
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
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 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
Mention of trade names does not imply endorsement by UA, CDC or other agencies.
RMSF in Arizona
• Now seen in many widely separated tribal lands (over 400,000 persons at risk)
• From 2002‐2013, 321 cases were identified
RMSF in Arizona
• Dog serosurveys
• 3‐50% across six tribal lands (avg. 28.5%)
• Arizona, non‐tribal lands 5%
 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
DHG
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Mosquitoes, ticks, biting midges
2/29/2016
Biological Features
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
Biological Features
Ticks move among hosts during high tick activity (interrupted feeding)
Nocturnal detachment of nymphal and adult engorged ticks concentrates ticks and facilitates host contact
Personal Repellent Use
• DEET (N, N‐diethyl‐3‐methylbenzamide)
– Use repellents containing 20‐30% DEET on exposed skin and clothing
– No greater than 15% for children
• Permethrin
– Can only be used to treat clothing (0.5%)
• Other repellents registered by the EPA
 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)
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
• Prompt tick removal reduces risk
Proper Tick Removal
DO NOT: use petroleum jelly, a hot match, nail polish, or other products to remove a tick
DHG
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
• Control ticks around your home 9
Mosquitoes, ticks, biting midges
2/29/2016
Home Assessment‐ What Are We Looking For?
Rhipicephalus sanguineus
Rhipicephalus sanguineus Infestation
Vegetation in surrounding areas increased moisture levels under houses on piers
Examine for suitable microhabitats around
the home:
• 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?
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
Treatment of Premises
• Outdoor
– Sprays
• Pyrethrins, Bifenthrin, Permethrin, Lambda‐
Cyhalothrin, Carbaryl
“Shady places where dogs lie”
Applications: Proper use of pesticides; Proper timing and dosage of application; Maximize safety

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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Reminder: Dog Population Control
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Animal control Spay/neuter programs can stabilize the situation
Dogs get sick also
– 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
DHG
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Mosquitoes, ticks, biting midges
Topically Applied Products
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Pyrethrins
Permethrin, Permethrin + pyriproxyfen
Fipronil
Fipronil + methoprene
Fipronil + amitraz + methoprene
Metaflumizone + amitraz
Selamectin
Useful Resources
• http://www.cdc.gov/rmsf/
DHG
2/29/2016
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
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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Mosquitoes, ticks, biting midges
2/29/2016
Mosquitoes can breed in……..
A.
B.
C.
Natural water
catchments, and manmade containers, but not
in irrigated lawns
In man-made containers
holding more than 1 pint
of water
Natural water
catchments, man-made
containers, and irrigated
lawn areas, but not
maintained swimmingpools
Brown dog ticks
A.
B.
95%
C.
0%
A.
94%
3%
5%
B.
Are intolerant to
high temperatures
Are relatively heat
tolerant
Prefer room
temperature
C.
A.
3%
B.
C.
Common sense
Use of trade names does not imply endorsement by UA, CDC or other agencies
DHG
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