Public Health Pest Control Flashcards
1
Q
What information can you find on
the pesticide label?
A
The label tells you how and where to use
a pesticide. It lists the pests the product
controls. The label gives you detailed
application instructions, including the
type of equipment you should use and the
correct rate of application. By reading
the label, you will discover how to store
the chemical properly. The label also
describes specific safety precautions.
2
Q
Why are schools considered sensitive
areas in relation to pesticide
application?
A
Because of the large number of young
children who attend them. Pesticide
applications on school grounds or inside
school buildings may leave residues.
Because of their behavior at play,
children are more likely to contact these
residues. And, because of their small
body size, children are more susceptible
to the effects of pesticides.
3
Q
What is the purpose of the Virginia
School IPM Program? How does it
accomplish this purpose?
A
This program encourages the responsible
use of pesticides in schools. It seeks
to reduce pesticide residues in the
environment and eliminate the chance
that children will contact pesticide
residues. It accomplishes this by educating school
administrators on how to implement
an IPM program at their facilities.
Schools then work with pest control
specialists to apply the concepts of
IPM when they treat schools. School
IM emphasizes prevention through
sanitation, building maintenance, and
other nonchemical means. If you work
with a School IPM program, you can
still use chemical control methods, but
only on an “as needed” basis. When you
apply pesticides in or around schools,
School IPM dictates that you use only
the least toxic, most effective products.
It also requires that you apply them
using “precision targeting.’
This means
that you place them only where they are
accessible to pests but not to students,
faculty, and staff.
4
Q
What is a beneficial insect?
A
An insect that is helpful to people, as in
the management of harmful plants or
animals.
5
Q
How can you protect honey bees
during a public health pesticide
application?
A
One way is to spray after dark. This
works because honey bees do not usually
forage in darkness (but they may forage
on bright moonlit nights). You can also
notify beekeepers of pending applications
so that they can cover or close their
hives. However, keep in mind that
colonies may be in remote locations, and
beekeepers may be reluctant to notify
authorities of their specific locations.
Thus, you may not be aware of the
presence of hives.
6
Q
When controlling adult mosquitoes
and flies, why is it important to
apply small droplets of pesticide vs.
large droplets?
A
Because of where the target pests occur,
For most other applications, the pest
- plant or insect - is on the ground or
on a plant on the ground. Thus, to treat
these pests, the pesticide must fall to
the ground or cover the foliage. Adult
mosquitoes and flies, on the other hand
spend much of their time in the air. For
this reason, you need your pesticide to
remain airborne for some time in order
to contact the insects. Small droplets are
able to stay suspended in the air longer
than larger droplets. In this way, they
extend the period that the target flying
insects are exposed to the insecticide.
7
Q
At what size can spray droplets
remain airborne for some time?
A
When their diameters are 150 um or less.
8
Q
What is the mass median diameter
(mmd) of a spray?
A
The droplet diameter at which half of
the volume of a spray contains larger
droplets and the other half consists of
smaller droplets.
9
Q
To control adult mosquitoes and
flies, which type of spray should you
use: a coarse spray, fine spray, mist,
or aerosol/fog? What is the average
droplet size of this type of spray?
A
Aerosol/fog. The diameter of the droplets
in this type of spray ranges from 0.01 to
50 um.
10
Q
Describe several ways you can
produce an aerosol/fog
A
You can use a thermal aerosol generator
or ultra-low-volume (ULV) equipment,
Thermal generator release the pesticide
directly into a blast of hot air to create
the tiny droplete. ULV equipment
produces aerosols with high-pressure
atomization from specialized nozzles, or
it may disperse the pesticide from the
rim of high-speed rotors. Household
bug bombs also produce aerosols, Bug
bombe work by mixing the pesticide
with a liquefied gas that is then released
through a small opening.
11
Q
Can you use an aerosol/fog to control
mosquito larvae? Why or why not?
A
No. Because aerosols stay suspended in
the air, they generally do not drop to the
water surface where the larvae are living.
12
Q
What is a temperature inversion?
How can it aid a pesticide
application that is targeting adult
mosquitoes or flies?
A
The occurrence of very stable air. This
means that the air above is warmer than
the air below. When the atmosphere
above the target gets warmer as altitude
increases, the air has a lifting action on
spray droplets. Small spray droplets
do not fall easily. Instead, they tend
to float around in concentrated groups
until eventually settling out. This can
cause droplets to drift. In public health
pest control, drift of the aerosol cloud is
desirable and essential. It increases the
chance that the pesticide will reach the
target insects. Temperature inversions
also help to hold aerosol droplets below
the canopy. This is because during an inversion, warmer air (that normally
rises) is up high and cooler air is down
low, holding the droplets down. Without
an inversion, warmer air is typically at
ground level. As it rises. it carries the
spray cloud upward.
13
Q
What is the most common type of
aerosol application today?
A
Ultra-low-volume application.
14
Q
How much pesticide is applied per
acre with most ULV applications?
A
From 1/2 to 3 fluid ounces.
15
Q
In Virginia, to apply pesticides
from the air, in which commercial
category must you be certified?
A
Category 11, Aerial Pesticide
Application.
16
Q
What are the basic parts of a ULV
application system?
A
Pump, nozzles, and a spray tank.
17
Q
What is the best spray droplet size
for aerial ULV applications? Why?
A
About 25 to 50 microns mass median
diameter (mmd). Droplets larger than 50
microns waste material, are not the right
size for killing mosquitoes, and do not
give good coverage. Besides, the hazard
to nontarget organisms and automobile
finishes increases with droplet size.
18
Q
How should you position the
spray nozzle for a ground ULV
application?
A
The nozzle should be in the rear of the
truck. It should be pointing upward at
an angle of 45° or more.
19
Q
What is the best mmd for most
ground ULV aerosol applications of
public health pesticides?
A
8 to 20 um.
20
Q
How can you prevent car spotting
(damaging the paint finish on cars)
during an aerial or ground aerosol
application?
A
Make sure the spray droplets are small
less than 50 um.
21
Q
How can you determine the size
of spray droplets that you are
applying? How can you adjust the
droplet size?
A
You can determine the droplet size in
several ways. The most common method
is to catch a sample of the droplets on
a silicone-coated glass slide. Then,
measure the droplets under a high-power
microscope with a micrometer. If the
droplets are too big or too small, adjust
your equipment accordingly. You may
also need to clean or replace the parts as
used, worn, and/or dirty parts can affect
droplet size.
22
Q
In what situation do thermal fogs
work better than ULV applications?
A
When you need to kill insects in heavy
vegetation.
23
Q
What are the safety risks of ULV
applications and thermal fogs?
A
Thermal fogs tend to pose a greater risk
to the environment. This is because
thermal fogging releases a cloud of fuel-
oil smoke with the pesticide.
The ULV method, on the other hand, may
pose a greater risk of applicator exposure.
This is because the insecticide used in ULV
application is more concentrated than the
diluted fuel-oil mixtures used in thermal
foggers. However, better equipment has
improved applicator safety in recent years.
24
Q
What is the purpose of this manual?
A
This manual is a reference book
that will enable you to prepare for
your certification exam in Virginia’s
Commercial Pesticide Applicator
Category 8, Public Health Pest Control.
Its purpose is to provide you with the
information you will need to safely and
effectively control public health pests.
25
List several topics covered by this
manual.
1. Basic pest biology to help you better
understand the relationship between
the groups of pests that cause most of
the public health problems in Virginia.
2. The many pests that can affect the
health and well-being of Virginians.
3. Some of the most common pest-related
diseases and other problems that
threaten public health in Virginia
4. Ways to prevent or control infestations
of public health pests.
5. Basic safety information that will help
you keep yourself, your coworkers, and
the public safe during public health
pesticide applications.
6. Pesticide application equipment and
techniques used to control public
health pests.
7. Basic organization of a good public
health control program.
8. The importance of good
communications in public health pest
control
26
What is an arthropod? Name several
groups of arthropods.
An invertebrate organism that has:
1. Jointed legs.
2. A body made of segments that are
grouped or fused together.
3. Legs, antennae, and other appendages
attached in pairs.
4. An exoskeleton, a hard or tough
external covering, with some pliable or
soft parts.
Examples of arthropods include spiders,
mites, ticks, millipedes, centipedes, and
insects.
27
Name and describe the three body
regions of an adult insect.
Head, thorax, and abdomen. The head
bears a single pair of antennae. The
thorax bears three pairs of legs and
usually one or two pairs of wings. The
abdomen contains most of the digestive
system and the reproductive organs.
28
List the five basic types of insect
mouthparts.
1. Filter feeding.
2. Chewing.
3. Sponging.
4. Piercing-sucking.
5. Siphoning.
29
Describe several sanitation actions
that can help to prevent or reduce
rodent populations.
Always store and handle food materials
and animal feeds properly. Store pet
food in metal, rodent-proof containers.
Properly store and regularly dispose
of garbage and rubbish. You should
also keep areas free of clutter. Debris
removal and weed control are key. For
example, to discourage rats, keep areas
around buildings and structures free of
weeds and stacked lumber, firewood, and
other stored materials.
30
How should you store commercial
products in order to reduce rodent
damage?
Store them on pallets at least 8 inches off
the ground. Keep the pallets 18 inches
from adjacent walls, and separate them
by an aisle that is at least 12 inches
wide. Do not stack pallets more than 6
feet across.
31
Describe several ways rodents can
enter buildings.
They run along or climb electrical
wires and cables that lead to buildings.
They climb trees and almost any rough
vertical surfaces such as wood, brick,
concrete, and weatherized sheet metal.
They crawl horizontally along pipes or
conduits. Rodents also gnaw through
a wide range of materials such as lead.
aluminum sheeting, wood, rubber, vinyl,
and concrete blocks, all to make their
way into a building. In addition, rodents
can enter buildings through holes that
are very small. For example, rats can
squeeze through openings larger than 1/2
inch square, Mice need only quarter-inch
holes. Conversely, rodents often enter
buildings through doors that stay open
for long periode,
32
If you discover a hole in your attic
or basement where rodents are
entering a home, what materials
would work well to seal that hole?
Durable materials, such as:
* Heavy mesh hardware cloth.
* Metal flashing.
* Aluminum (22 gauge or thicker).
* Brick.
You can also pack steel wool, lath screen
and copper mesh tightly into holes to
close openings or protect other areas
from gnawing. Be sure to caulk over
steel wool and copper mesh to seal them.
33
What are the advantages of trapping
rodents as a method of control?
Trapping does not rely on hazardous
rodenticides. It provides visible proof of
success. In addition, trapping allows you
to dispose of carcasses. This avoids odor
problems from decomposing carcasses
that could occur when poisons are used
inside buildings.
34
When trapping rodents with trigger
traps, where should you place the
traps for the best results?
Close to walls, behind objects in dark
corners, and in other areas of known
rat and mouse activity. Place traps so that rats and mice will pass directly
over the trigger as they follow their
natural course of travel (usually close
to a wall). Set traps on ledges or on top
of pallets of stored materials, if rodents
are active in these places. Cover all
escape routes with traps. Use enough
traps to make the campaign short and
decisive. Because mice seldom venture
far from their shelter and food supply,
place trigger traps 3 to 10 feet apart in
areas where mouse activity is noted, and
within 20 feet of each other for rats.
35
How long should you leave traps in
place before moving them to another
location?
Five days. Intensive trapping for several
weeks works best.
36
What is a drawback of using glue
boards to catch rodents?
The animals do not die instantly.
37
What are the disadvantages of using
noise or electrical devices to control
rodents?
Rodents quickly get used to regularly
repeated sounds. In addition, ultrasonic
sounds have very limited use in rodent
control because they are directional, they
do not penetrate behind objects, and they
lose their intensity with distance. In
fact, there is little evidence that sound of
any type will drive established mice or
rats from buildings.
38
How do anticoagulant baits kill
rodents?
Repeated ingestion causes the animals'
blood to lose its ability to clot. Animals
die due to internal bleeding that begins
about three to five days after they first
eat the bait.
39
In what situations would you use a
single-dose rodenticide vs. a slow-
acting (multiple-dose) rodenticide?
Single-dose rodenticides work best
where rodents are abundant or where
it is hard to get the animal to accept a
bait for several days in a row because of
competing food items.
40
What is the purpose of a bait station?
Describe a basic bait station used to
bait rodents.
Bait stations shelter rodenticides from
weather and protect people, pets, and
other animals from accidental poisoning.
Bait stations, should have at least two
openings, about 2-1/2 inches in diameter
for rats or 1 inch in diameter for mice.
Be sure each station is large enough
to accommodate several rodents at one
time.
41
When baiting mice, what type of
bait can help to prevent the mice
from moving the bait to an area that
could endanger nontarget animals?
Meal baits.
42
What is prebaiting? Why is it
important?
Placing nontoxic bait (food) in a trap
or bait station. Once the target pest
becomes used to feeding from the trap or
bait station, the nontoxic bait is replaced
with toxic bait. Prebaiting ensures that
the target pest eats enough of the toxic
bait and does not become bait shy.
43
What are tracking powders, and how
do they work?
Tracking powders are rodenticides formulated as dusts. The powder adheres to the rodents' feed and fur and is consumed during grooming. These powders can kill rats even when the animals have become bait or trap shy.
Apply tracking powders inside wall voids, around rub marks, along pipe runs, and in dry burrows (if the label permits).
Do not use the powders in suspended ceilings, around air ventilators, or near food preparation areas.
44
In which commercial category might you need to be certified to use fumigant pesticides in Virginia?
To use certain fumigants to control pests in Virginia, you may need to be certified in commercial category 1C, Fumigation of Soils and Agricultural Products, or in commercial category 7C, Fumigation (Non-Agricultural). Contact the Virginia Department of Agriculture and Consumer Services (VDACS) for more information on which category 15 required for your situation
45
Why are odor repellents generally
not effective against birds?
Because few birds can smell.
46
Against which type(s) of pest bird is
nest and/or egg destruction effective?
Pigeons.
47
What is the most cost-effective way
to destroy pigeon nests?
Using high-pressure hosing from
firefighting equipment or other water
lines. This destroys the nest, kills
ectoparasites, cleans droppings and
feathers from the nest site, and harasses
the roosting birds.
48
List several ways you can prevent
pest birds from entering buildings.
1. Eliminate large crevices.
2. Block openings into vents, cooling
towers, and rooftop equipment with
hardware cloth,
3. Replace broken windows and screens.
49
Describe several exclusion materials that can discourage or prevent birds from nesting, roosting, or loafing on buildings
1. Spikes will help to prevent birds from roosting on ledges
2. Netting may exclude birds from the eaves of a building or the internal support structure of a large warehouse,
3. Covers or ramps designed for ledges, window air-conditioning units, and roof edges can keep birds from infesting these sites.
50
Do ultrasonic sound devices
effectively scare and/or harass birds?
No.
51
What is the advantage of traps that
capture pest animals alive?
They allow you to release nontarget
species unharmed.
52
Ideally, where should you place pigeon traps?
In general, you will want to set traps where the pigeons often roost or feed. Be sure to place the traps in inconspicuous sites where people are not likely to vandalize them a major risk in trapping programs).
53
Traps are LEAST effective against
which type of pest bird discussed in
this manual
Starlings.
54
What should you do before setting a
funnel trap to make sure it captures
the largest number of sparrows?
Bait the trap for a few days.
55
If you plan to use shooting as a bird control tactic, what time of day and what location will yield the best results?
At night or first thing in the morning in roosting areas.
56
How do sticky repellents repel roosting birds from buildings?
They make birds uncomfortable as they try to land on treated surfaces. After a few attempts, the birds will usually stop trying.
57
What reduces the effectiveness of
sticky repellents? How can you
remedy these problems?
Over time, sticky repellents lose their
effectiveness, especially in dusty areas.
When this happens, you will need to make
a second application. Sticky repellents will
also be ineffective if you treat only some of
the roosting or loafing sites in a problem
ared.
Whenever possible, the birds will
move a short distance to an untreated
surface. For this reason, it is important to
treat all roosting and loafing surfaces in a
given area.
58
How do frightening baits work to control pest birds?
Within 15 minutes of eating a toxic dose, birds become intoxicated and begin to react violently. Most die within a few hours. The rest of the flock is frightened away from the site. Only 5% to 15% of the flock need to be affected to scare away the rest of the flock.
59
Using pigeons as an example, describe the basic prebaiting process for birds.
One method is to place untreated whole corn in many small piles (1/4 pound each 20 feet apart). Place these piles on flat rooftops, on ledges, and in similar sites in the treatment area.
An appropriate treatment would be 20 piles of bait on a flat 5,000-square-foot roof.
Another method is to scatter the bait in a natural manner. Flocks of birds will feed better on bait that is scattered and accessible to
more birds.
The goal is to get at least 40% of the birds to accept the untreated bait.
Expect the effort to take from three days to three weeks. When possible, remove all of the untreated bait before switching over to treated bait.
60
How can prebaiting help you to protect nontarget species?
It allows you to observe what species of birds feed at your site before you place the toxic bait. If several nontarget animals begin feeding at the site, you have two options.
One: if the prebait site is one of many, you can continue to bait the isolated site with untreated bait. This will keep the nontargets away from the other sites where you can use toxic bait.
Two: if you are only prebaiting at one or a few sites, you may need to abandon the site where the nontargets appeared.
61
How much toxic bait should you
put out in relation to the amount of
prebait you used?
The amount of treated bait you set out
should be about half the amount of prebait
you used each day. For example, if you put
out 8 pounds of prebait daily for a flock of
about 100 birds, then you should set out 4
pounds of the treated blend of bait.
62
Q. What can you do to protect yourself
from contracting a disease through
the bite of a mosquito?
Unless you are applying adulticides,
avoid working outside at dawn and
dusk when mosquitoes are most active.
When working outside, avoid known
mosquito habitats, and make yourself as
unattractive to mosquitoes as possible.
To do this:
1. Wear light-colored clothing.
2. Cover your arms and legs with long
sleeves and long pants.
3. Apply an insect repellent to any
exposed skin.
63
What can you do to protect yourself
from contracting a disease through
the bite of a tick?
Avoid tick-infested areas, such as tall
grass and dense vegetation. If you
must work in these areas, follow these
guidelines:
1. Wear light-colored clothing so that
ticks are easier to see and remove.
2. Wear long sleeves and long pants.
Tuck your pants into your socks and
your shirt into your pants.
3. Apply tick repellents to any exposed
skin and an approved toxicant to your
clothes.
4. Walk in the center of trails to avoid
brushing against vegetation.
5. Check your body and clothes for ticks
during and after being outdoors.
64
What can you do to protect yourself
from contracting a disease that is
transmitted through the air from
accumulations of animal feces?
1. If you work in an area where bird
or bat droppings have accumulated for
several years, wear disposable clothing
and a dust/mist respirator approved
by the National Institute for
Occupational Safety and Health
(NIOSH).
2. Do not stir up or breathe dust. If
you are going into a closed building,
garage, or basement, open it and let
it air out for at least one hour before
working inside. Gently spray down
areas, including soil, that may be
contaminated with animal feces or
urine. You can use a commercial
disinfectant such as Lysol spray or
prepare a solution of 1-1/2 cups bleach
to 1 gallon of water. Use a spray
bottle to mist the area gently. A hard
spray will just stir up more dust. Be
sure that all surface and soils get
thoroughly wet.
3. If you need to clean up large amounts
of bird or bat droppings, wet the
droppings first to keep spores from
becoming airborne. Then, put the
droppings into plastic garbage bags.
Seal the bags and wet down the
outside. Dispose of the trash bags.
4. When you finish working in high-risk
areas, remove your disposable gloves
and protective clothing and place them
in plastic garbage bags. Dispose of
the trash bags. If you are wearing a
respirator, keep it on during this step.
5. Wash up or shower at the end of the
day or the end of your task. If you
used a respirator, clean it before
putting it away. Be sure to change
cartridges as/when needed.
65
What are chemosterilants?
Often called "birth control pills," these
chemicals control pigeons by preventing
ovulation in the female and sperm
production in the male. These effects
can last for six months in the female and
three
months in the male. When applied
as directed on the label, chemosterilants
will not kill birds. Instead, populations
will slowly decline over the years from
the natural mortality in an aging pigeon
population.
66
What is the best way to get rid of
most bats?
Exclude them from structures.
67
If you are called to bat-proof a home
in June or July, why might you
recommend that the homeowner
wait until late fall?
Because in June or July, most bats are
rearing young in their colonies. The
young cannot fly, so bat-proofing during
this period will trap the young bats
inside, where they will die. The young
bats may also crawl and Autter into
living areas. In late fall, however, bats
have left for hibernation. You can also
delay bat-proofing until late winter and
early spring before the bats arrive.
68
Do ultrasonic sound devices repel
bats?
No.
69
What is the best way to prevent
problems with snakes?
Eliminate snake hiding places. Clean
up brush piles, woodpiles, rock piles, and
other debris. Keep shrubs away from
building foundations and cut high grass.
Get rid of their source of food (ex. mice
and rats).
70
Describe several ways you can
remove a snake that gets into a
house or other building.
One method is to place damp burlap
sacks on the floor and cover them with
dry sacks. Check the sacks every few
hours to see if the snake has crawled
underneath. Once the snake is within
the pile of sacks, you can lift the snake
and bags with a shovel and take them
outside.
Another option is to use rat glue
boards. These glue boards will capture
all but the largest snakes. Tie down or
attach the glue boards to a plywood base.
Then, place the glue boards along wall
and floor junctions. Once the snake has
been caught, you can kill or release it. To
loosen a snake from a glue board, pour
vegetable oil over the snake and glue.
Lastly, you can use expanded trigger rat
traps to catch and kill smaller snakes.
Set the traps in pairs along wall and floor
junctions. Keep children and pets away
from the traps.
71
How can you protect nontarget
animals from exposure during
public health pesticide applications?
1. Identify the other animals in the area.
2. Use nonchemical control tactics
whenever possible.
3. Monitor operations to be sure that
they are not harming nontarget
animals.
4. When baiting, remove and destroy
all uneaten bait at the end of the
poisoning period. Do not leave single-
dose baits exposed for more than three
or four days.
These baits are often
more toxic than multiple-dose baits.
5. For rodenticide baits, place them
where only rodents can get them. For
avicide baits, be sure to prebait the
site before adding toxicant to the bait.
6. Choose the proper bait for all target
animals.
7. Place the bait carefully to discourage
nontarget animals from feeding on the
bait.
72
What personal protective equipment
(PPE) should you wear when
preparing baits for rodents, birds,
or other vertebrates? What other
steps can you take to reduce your
exposure?
Wear rubber gloves, an apron, and a
proper respirator. Wash up thoroughly
after preparing any bait. Use soap, a
cleaning brush, and plenty of water.
Clean bait-mixing utensils thoroughly,
and use them only for bait preparation.
Whenever possible, buy prepared or
ready-to-use baits. This will reduce the
risks involved in handling concentrated
toxicants.
73
Describe several ways in which
diseases are transmitted to humans.
1. Vector transmission - A disease
vector is a living organism that carries
a disease.
2. Respiratory transmission - Many
disease-causing organisms are
released into the air when something
or someone disturbs the feces of
an infected organism. If a person
breathes these particles, he or she can
contract the disease.
3. Penetrating wound transmission -
Some organisms need a direct
entrance into the human body to cause
disease. A wound that penetrates the
skin can provide the ideal opening.
People can contract these diseases
through an animal bite, scratch, or
other injury that breaks the skin
4. Fecal oral transmission - Many
pathogens live in the feces of other
organisms. "Fecal oral transmission"
occurs when people contact infested
feces and then transmit the disease
from their hands to their mouth.
5. Direct contact transmission -
Sometimes humans can contract
diseases simply by handling infected
organisms or by contacting tissues or
Aids from infected organisms. (This
is also how mites, lice, fleas, and other
parasites can transfer to people.)
74
How is plague usually transmitted?
By fleas.
75
What form of plague has killed the
most people?
Bubonic.
76
Name several diseases transmitted
by house flies.
Dysentery, cholera, and typhoid fever.
77
What is the most prevalent vector-
borne human disease in the United
States today?
Lyme disease.
78
Where in this country does Lyme
disease occur?
Endemic areas in the United
States include the East Coast from
Massachusetts to Virginia, Pennsylvania,
Wisconsin, Illinois, the upper peninsula
of Michigan, northern California, Oregon,
and southern Washington.
79
What is the most likely vector of
Lyme disease in Virginia?
The deer tick.
80
Briefly describe how Lyme disease is transmitted to humans and other animals.
Transmission usually occurs in the nymphal stage, which is most active in late spring and summer. Although white-tailed deer are the primary hosts of the adult ticks, deer do not carry Lyme disease. Instead, rodents serve as the main reservoir from which tick larvae get the parasite. The parasite then passes transstadially to nymphs and adult ticks.
Humans, dogs, and wildlife can contract Lyme disease through the bite of an infected tick. However, the tick must remain attached to the body for ten hours or longer for the bacteria to transfer from the tick to the host. You cannot get Lyme disease from animals or other people.
81
Describe how ehrlichiosis is
transmitted to humans.
By the bite of an infected tick.
Transmission occurs mostly from May
through July when ticks are most active.
The main vectors include the American
dog tick, the lone star tick, and the deer
tick. White-tailed deer are natural
reservoir hosts for ehrlichiosis and may
serve as a source of infection for the lone
star tick in all life stages. Ehrlichiosis
cannot spread from person to person.
82
What is tick paralysis?
A condition that begins as muscle
weakness and develops into paralysis
throughout the victim's body. It is
caused by toxins injected as an infected
tick feeds on its victim.
83
How do people get tularemia? When
is infection most common?
1. Their skin or membranes may become infected while they skin, butcher, or handle infected animals. They may also inhale contaminated dust, eat contaminated meat, drink contaminated water, or contact infected blood.
2. They may be bitten by an infected tick, deer fly, or mosquito. Ticks are the primary vector. Cases occur year-round but are most common during the fall and winter hunting seasons. Tularemia also occurs in the summer when people are outdoors and ticks or other vectors are abundant.
84
What is a vertebrate?
An animal with a spinal column or
backbone. such as a bird or mammal
85
When are vertebrates considered
public health threats?
When they harbor dangerous pathogens
that can harm people. Vertebrates can
transmit diseases to humans directly,
through a bite or other means. They
can also be the primary reservoir for
a disease that is then transmitted to
humans with the help of an arthropod
Other vertebrates are dangerous because
their bites contain deadly venom.
86
How can you distinguish between an
adult house mouse and a young roof
rat?
The head and feet of the house mouse
are distinctly smaller in proportion to its
body size.
87
Describe the feces of the house
mouse, roof rat, and Norway rat.
House mouse feces are about 1/8 to 1/4
inch long and rod shaped. Roof rat feces
are about 1/2 inch long and spindle
shaped. Norway rat feces are capsule
shaped and about 3/4 inch long.
88
Do house mice live only inside
structures?
No, they are also well adapted to living
outdoors. You will often find house mice living in grassy fields and in cultivated grain crops. Outdoor populations often move into buildings in bad weather.
89
What physical feature do house mice
have that helps them move around
in the dark?
Long, sensitive whiskers on their nose
and above their eyes.
These whiskers
serve as tactile sensors. They enable the
mice to travel easily in the dark along
runways close to walls.
90
When do house mice most often feed?
Peak feeding periods are at dusk and just
about dawn. However, because of their
small size, house mice must feed several
times during a 24-hour period and, thus,
are active day and night.
91
Of the rodents discussed in this
manual, which species is the best
swimmer?
The Norway rat.
92
Describe the differences between
the tail of the Norway rat and the
tail of the roof rat.
A Norway rat's tail is dark on the top and
light underneath. Tail length (6 to 8-1/2
inches) is less than the combined length
of the head and body (7 to 10 inches).
A roof rat's tail is single colored. Tail
length (7-1/2 to 10 inches) is usually
longer than the head and body of the rat
combined (6-1/2 to 8 inches).
93
Name several places in which
Norway rats live.
Norway rats live in warehouses, farm
buildings, houses, sewers, rubbish
dumps, woodpiles, and building
foundations.
94
Describe the mouthparts of an
arachnid.
Arachnids usually have mouthparts with
two prominent structures: pedipalps and
chelicerae. In spiders, the pedipalps are
leglike structures, and the chelicerae
have needlelike fange attached.
95
How many pair of legs do centipedes
have per body segment?
one
96
What is the difference between
simple, gradual, and complete
metamorphosis?
Simple metamorphosis - A
development process in which an
insect makes no drastic change in form
from juvenile to adult. It simply
hatches and grows larger by molting
periodically.
2. Gradual metamorphosis - A
development process in which insects
hatch from eggs as nymphs that
resemble the adult form but do not
have wings.
3. Complete metamorphosis - A
development process in which insects
undergo a complete change in
appearance from juvenile to adult.
Insects with complete metamorphosis
hatch from eggs as larvae (grubs,
maggots, and caterpillars). Each
larva feeds, grows, and continues to
develop without changing form. Then,
it changes into a pupa, which is often
immobile. During the pupal stage,
the body changes form. Many insects
develop wings and some, such as fly
larvae, develop legs. At the end of the
pupal stage, an adult insect emerges.
Reproduction occurs during the adult
stage.
97
Why might you need to manage
each life stage (egg, larva, pupa,
and adult) differently for pests that
undergo complete metamorphosis?
Because each developmental stage
often has different needs and habitats.
The pests may also live in different
environments. For example, the larvae
of many insects feed and live in one
habitat and then leave that area to
pupate a short distance away.
The
adults that emerge require a different
food source and live in another area.
They may return to the larval feeding
sites only to lay eggs. For this reason,
you must manage species with complete
metamorphosis according to where their
different developmental stages live and
how they behave.
98
What is a major difference between
vertebrates and arthropods?
Vertebrates have a spinal cord that
is usually surrounded by a backbone
or vertebral column. This structure,
the skeleton, allows vertebrates to
grow continually because the skeleton
is internal. Arthropods, on the other
hand, are invertebrates. They lack an
internal skeleton and instead have an
exoskeleton.
99
Why are sanitary sewers so
appealing to Norway rats?
In cities with older systems, sanitary
sewers may be connected to storm sewers.
This provides the rats with
several entry points and access to a large
food source. The connected sewers of
such a community provide enough food to
sustain many rats. Norway rats are also
excellent swimmers
100
What physical abilities do Norway
rats have that help them to move
around and invade specific places?
Norway rats are good climbers and can
reach up to 13 inches while standing
on the ground.
They can also jump 24
inches
straight up.
101
How can you tell a white-footed
mouse from a house mouse?
By its fur. The white-footed mouse is
brown-gray on top and white below.
It
also has a distinct, bicolored tail (upper
half brown-gray, lower half white).
102
Which rodent is most often
associated with human hantavirus?
The deer mouse
103
If you rat-proof a warehouse, why
might a new population of house
mice develop in its place?
Because when you free a building of rats,
house mice can move into previously
occupied spaces or they can increase in
numbers. This happens because there is
less competition with rats or because the
mice can enter and colonize areas that
have been rat-proofed.
104
Why are you more likely to see signs
of a rodent infestation than the
rodent itself?
Because rodents are nocturnal and are
wary of noises and human activity.
105
List several signs that may indicate
the presence of rodents.
Urine along well-used runways.
2. Smudges or rub marks on pipes and
heams
3. Gnawing marks around baseboards,
doors, windows and frames, and
kitchen cabinets.
4. Droppings along runways, near
burrow entrances, and at feeding sites.
5. Pet excitement.
6. Odor.
7. Runways between their shelter, food,
and water sources.
8. Tracks along runways and other
areas.
106
If you see old rodent droppings,
gnawing, and one or more rodents by
flashlight at night but none during
the day, would this infestation be low,
medium, or high in density?
Medium.
107
In what ways can birds be a public
health threat?
Serious health risks arise from disease
organisms that grow in accumulations of bird droppings, feathers, and debris under a roost. When parasite-infested birds leave roosts or nests to invade buildings, their parasites can bite, irritate, or infest people.
Birds may also contaminate food, but this risk is usually limited to food-manufacturing or processing plants.
Birds may also act as reservoirs for vector-borne human diseases.
108
What do pigeons eat in urban areas?
Garbage, spilled grains, insects, food left
by outdoor diners, and food provided by
bird lovers who feed them.
109
Where do pigeons feed in urban
areas?
Pigeons prefer flat and smooth
surfaces. Feeding sites include parks,
squares, food-loading docks, garbage
areas, railroad sidings, food plants,
and wherever people eat outdoors.
In
addition, unlike most birds, pigeons will
feed from rooftops, regardless of height.
They like the openness of rooftops
because it allows them to escape easily.
110
Describe several problems caused by pigeons.
They damage public and personal
property, cause sanitation problems,
and threaten human safety.
Pigeon droppings deface buildings and speed their decay. Around grain-handling facilities, pigeons eat and contaminate food destined for people or livestock.
Pigeons can carry and spread diseases
to people through their droppings and
feathers. Pigeons carry various species
of mites, fleas, and ticks, many of which can harm people. In addition, insects that inhabit pigeon nests in buildings are not only external parasites of people, but they are also fabric and pantry pests. Finally, pigeons can be a threat to human safety around airports when they collide with jet aircraft.
111
Where do starlings like to nest in
urban areas?
On buildings, in birdhouses, and on
power stations, water towers, and other
structures.
112
What time of year are starlings
the most troublesome in cities and
towns? Why?
In the fall and winter. This is because as
cold weather begins in the fall, starlings
start to form larger flocks. Their main
food sources shift from insects and fruits
to grains, seeds, livestock rations, and
garbage. Starlings may abandon rural
and suburban roosting areas and move
into cities and towns. Each day they may
fly up to 30 miles to their feeding sites.
113
Why are house sparrows considered pests?
The birds cause damage by pecking at rigid foam insulation in buildings and nesting inside traffic lights. They create fire hazards by nesting in transtormers and power stations. They also transmit of a number of diseases, internal parasites, and ectoparasites to people.
Accumulations of their droppings and feathers are hazardous, unsanitary, and smelly. Feces and feathers collect inside and outside of buildings, on sidewalks, and under roosting sites.
Sparrow droppings also contaminate stored grain and bulk food. Sparrows may also become pests when they nest inside a food plant, warehouse, mall, or atrium.
114
What state agency should you
contact to find out about laws
and regulations that might affect
vertebrate control actions?
The Virginia Department of Game and
Inland Fisheries (VDGIF).
115
When surveying a bird population,
what information should you
record?
Surveys should:
1. Identify the target and nontarget
species involved.
2. Label the birds as resident, migrant,
adult, or juvenile.
3. Count the target population.
4. Identify the activity of the birds as
feeding, roosting, nesting, or loafing.
5. Determine the source(s) of food and
liquids.
6. Estimate the health and damage risks
they present.
One way to take a "census" of a bird
population is to spread out some bait
and count the number of birds that come
to feed. Another way is to count the
number of birds observed in a certain
area during a specific period. The second
method is especially common.
116
Why are bats sometimes considered
public health pests?
Because they are associated with a few diseases
that affect people. The most serious of these are rabies and histoplasmosis. Rabies is
transmitted to humans through the bite of an
infected bat or by inhaling dust from virus-
contaminated bat feces. Histoplasmosis
also develops in bat feces. Both diseases can
be fatal. In addition, when large colonies or
groups roost in buildings, their droppings and
urine can cause a foul odor and stain walls
and ceilings. Their squeaking and scrambling
noises can be intolerable to residents. When
they leave buildings, they may also cause
damage and/or create new openings.
117
When/why do bats enter buildings?
To roost, to hibernate, and to give birth.
118
How can you distinguish bat feces
from mouse feces?
Bat feces contain wings, legs, and other
insect body parts.
119
How can you locate the points where
bats are entering and exiting a
building?
Look for loose flashing, vents, shingles,
and siding. Other clues are droppings
under openings, smudges around holes,
and odors. Near twilight, you can also
watch for bats as they leave a building to
feed.
120
What are the basic features of a
poisonous snake?
In general, poisonous snakes in Virginia
have a large triangular head, a pit
between the eye and nostril, and vertical,
elliptical pupils. They may also have
rattles on their tail and noticeable fangs.
When you are unsure, assume that the
snake may be poisonous.
121
Why might a snake enter a home or other building?
Warmth
Shade
Moisture
Search of prey
122
Describe the symptoms of a bite by a
brown recluse spider.
Brown recluse spider bites are sharp
but not initially painful like those of the
black widow. A blister is quickly raised,
broken, and surrounded by a red welt.
The depressed center of this raised red
circle (the size of a dime to a quarter)
turns dark within a day. In most cases,
the dead tissue sloughs away, and the
bite area scars over in one to eight weeks
However, some people develop a wound
with so much dead tissue that they need
skin grafting. Death seldom occurs, but
the bite is debilitating and psychologically
traumatic. Other biting arthropods can
produce lesions that resemble the bite of
the brown recluse spider. This spider is
rarely found in Virginia.
123
What other spider often causes
concern? Why?
The yellow house (yellow sac) spider will
bite if pressed or accidentally confined
(ex. during the victim's sleep). The
venom can cause pain and reddening
at the site of the bite. In some cases,
a deadening of the tissue will occur.
However, the wound is much less severe
than that caused by the brown recluse
spider.
124
Describe the symptoms of a
poisonous snakebite.
These can differ greatly from person
to person. One individual may react
to the venom with basic signs like
pain, swelling, and/or bleeding. Signs
of a severe reaction include skin
discoloration, low blood pressure, and/
or tingling of lips and tongue. Most
snakebites are painful.
125
If you or someone else is bitten by a snake or spider, what are some important things you need to do?
If possible, etch and kill the animal and take it to a physician for positive identification. Although the most important thing is to seek prompt medical treatment, first aid may include, Washing the area well with soap and water. Applying a cold ice pack wrapped in a cloth or a cold, wet washcloth to the Bite, Applying an antibiotic lotion or cream to protect against infection. Elevating the site to prevent swelling if the bite occurred on an arm or leg,
126
Describe the relationship between
the pathogen, vector, and host.
A pathogen is the organism that causes a
disease (ex. virus). In general, pathogens
need help to move from one host to
another. A vector is the organism (ex.
insect) that passes the pathogen to a host
(ex. human or animal). Sometimes, a
host is also a vector. In these cases, after
receiving the pathogen, the host will pass
the pathogen to another host.
127
Name the two basic modes of disease
transmission. Describe each one.
Most modes of transmission are either
mechanical or biological:
1. Mechanical transmission occurs when
a vector transports a pathogen on the
outside of its body. The pathogen may
adhere to the vector's feet, body hairs,
or other body surfaces. The pathogen
does not develop or reproduce within
the vector's body.
2. Biological transmission occurs
when a pathogen develops within
the vector's body instead of simply being transported by contact with the
vector's body parts, as in mechanical
transmission. Often, the vector
transmits the pathogen through a bite.
Other times, a new host will contract
the disease through exposure to the
vector's feces, blood, or urine.
128
What is a dead-end host? Give an example discussed in this manual
A disease-infected host from which a susceptible vector organism cannot acquire an infection.
Horses and humans are dead-end hosts for some types of encephalitis.
129
Is the virus that causes AIDS
transmitted by mosquitoes and other
bloodsucking insects?
Currently, there is no scientifically
based, credible evidence to suggest that
mosquitoes or other biting arthropods
can transmit the AIDS virus to humans.
130
What is an intermediate host?
An organism in which the asexual stages
of a parasite or pathogen live.
131
What is a primary host? Give an
example discussed in this manual.
The organism in which a parasite or
pathogen completes the sexual portion of
its life cycle. Also called the "definitive
host." White-tailed deer are the primary
hosts of adult ticks.
132
What is an ectoparasite? How do
ectoparasites transmit diseases?
A parasite that lives permanently or
intermittently on the outside of its host's
body. Examples of ectoparasites include
fleas, lice, and ticks. These organisms
transmit diseases by carrying a pathogen
on the outside of their body.
133
What is an obligatory disease vector?
Obligatory vectors of disease are those in
which the parasite must live to complete
its life cycle. Malaria is an example of
a disease that needs a vector (mosquito)
to develop from one stage to another.
Without a mosquito, the malaria parasite
would die. Mosquitoes are obligatory
vectors of many diseases.
134
What is a reservoir host?
An organism (also called "reservoir") that
harbors a pathogen over an extended
period. The pathogen can live in a
reservoir host without making the host
sick. Disease transmission can occur
when a vector feeds on the reservoir host
and then feeds on another, susceptible
host. Birds are examples of reservoirs
for mosquito-borne encephalitis.
135
What is transovarial disease
transmission?
When a vector passes a disease to its
offspring through the eggs. Eggs infected
in this way produce infected larvae.
The later adult stage will also carry the
disease. These adults can transmit the
pathogen without needing to feed on an
infected host. Transovarial transmission
occurs with several mosquito-borne
viruses and with Rocky Mountain
spotted fever (RMSF). In these cases, the
mosquitoes and the ticks serve both as
reservoirs and as vectors.
136
Briefly describe the transmission
cycle of the St. Louis encephalitis
(SLE) virus.
Its natural transmission cycle involves
several species of wild birds and a few
species of mosquitoes. The virus is
briefly present in the blood of an infected
bird. A mosquito ingests the virus when
it feeds on an infected bird. After one
to two weeks at summer temperatures
(longer at cooler temperatures), the virus
multiplies and spreads
137
What types of mosquitoes are most important in transmitting SLE?
Those that are highly susceptible to the virus and those that feed mainly on birds.
138
Can all mosquitoes transmit the SLE virus? Why or why not?
No, because the virus is not able to multiply in certain species of mosquitoes.
In these cases, even when the mosquito feeds on an infected bird. it cannot transmit the virus.
139
Does SLE have any dead-end hosts?
Yes. Humans, other mammals, and some bird species are dead-end hosts for SLE.
140
In what form and where do Cx. pipiens mosquitoes, the species most often associated with SLE transmission, overwinter? When they emerge, where do they lay their eggs?
Adult female Cx. pipiens often overwinter in outbuildings, attics, storm sewers, and rodent burrows. When they emerge, they usually place their eggs on the suface of organically polluted water.
141
When do human outbreaks of SLE normally occur?
In the late summer.
142
Why does SLE often occur in urban areas?
In these sites, suitable bird and mosquito species often live close to people. For example, urban areas are home to sparrows, starlings, and other birds as well as Culex pipiens, the northern house (or brown house) mosquito. This mosquito likes urban areas because of the many artificial water-filled containers (ex. bird baths and water gardens) located in and around homes and buildings.
These containers provide ideal breeding sites for the mosquitoes.
143
How can drought conditions lead to an outbreak of SLE?
Drought conditions can cause polluted streams to pool and produce Culex mosquitoes. This is because during a drought, rainwater does not flush and/or dilute streams and pools. Instead, these waters may become stagnant, and, thus, are more attractive for mosquito breeding. In addition, under extreme drought conditions, streams may recede from their banks, leaving pockets of water (pools). These pools often contain high levels of organic material, such as decaying leaves. Such pools are ideal breeding places for Culex mosquitoes. Also, during a drought, birds and mosquitoes may come into more contact at these pools.
144
Name two dead-end hosts for EEE.
Humans and horses.
145
What two factors favor infections of EEE in humans?
1. The buildup of the virus in wild-bird populations.
2. A high density of adult mosquito vectors.
146
Describe how health departments and mosquito-control districts often monitor for EEE.
They may periodically collect blood samples from wild birds or sentinel flocks. If a bird has been exposed to the virus, it will produce antibodies. Young birds with high antibody levels mean recent exposure to the virus. Older birds with antibodies indicate exposure a year ago or earlier. Periodic outbreaks among nonvaccinated equines (horses) also provide evidence of local EEE viral activity.
147
How does the natural cycle of LAC differ from SLE, EEE, and WEE?
For LAC, the natural hosts are small mammals such as chipmunks and squirrels. The vectors are mostly woodland mosquitoes. Most of the human cases develop in people who live or work in or near wooded areas.
148
Why do many cases of WNV go undiagnosed?
Because of mild or nonexistent symptoms.
149
What genus of mosquitoes transmits
WNV?
Culex spp.
150
Under what conditions does Ae. aegypti transmit dengue?
This species lives closely with humans.
It breeds in natural and artificial water-holding containers around dwellings.
After biting an infected person, the female mosquito needs eight to ten days for viral development before it can transmit the virus to humans.
151
In what parts of the world is malaria the most prevalent? Who is the most vulnerable to the disease?
Africa and Asia. More than 2 million people die each year from the disease.
Most of those are children under ten years of age.
152
When and why did the number of cases of malaria begin to decrease in this country?
By the early 1940s, the number of cases of malaria in the United States dropped dramatically. This was largely due to the work of public health agencies using DDT during and after World War II and the Tennessee Valley Authority (TVA) source-reduction program
153
Does malaria still occur in the United States? Explain.
Yes. Since the late 1950s, a few hundred to a few thousand new cases of malaria occur in the United States each year.
Most are brought in by travelers and military personnel returning from malaria-infested areas. However, because mosquitoes that can carry malaria live in Virginia, it is possible to have local transmission. This might occur if, for example, an infected person returns to Virginia from Africa. Local (indigenous) mosquitoes may feed on this person and become infected with malaria.
Finally, an infected mosquito may transmit the parasite to someone with no history of travel. There are documented cases (especially in Northern Virginia) of human malaria being transmitted in this manner from infected hosts to uninfected hosts by indigenous mosquitoes.
154
What genus of mosquitoes transmits malaria? When are they most abundant?
Anopheles spp. These insects are most abundant from April to September.
155
Describe the life cycle of dog heartworm.
The life cycle of the dog heartworm involves two hosts: mosquitoes and dogs.
Mosquitoes ingest immature worms while taking blood from dogs. These worms develop through three larval stages in the mosquito in nine to 14 days. After they develop into infective or third-stage larvae, the mosquito transmits the worms to a dog when the mosquito feeds on the dog. The larvae grow and migrate through the dog's tissues and large blood vessels.
Eventually, they enter the right ventricle of the heart. In the heart, the larvae grow into adult worms. Adult worms measure about 11 inches for the females and 6 inches for the male. The adult female produces immature worms that circulate in the dog's blood, completing the cycle.
