This lesson reviews the features of mites and ticks that affect
Read Chapter 12 page 145-146, and Chapter 13 pages
172-195 in “Diagnostic
Veterinary Parasitology for Veterinary Technicians”
3rd edition by Hendrix
There is a writing assignment at the end of this lesson. Please turn
in your answers by email.
Learn the anatomical features of various mites and ticks
Learn the life cycles of representative mites and ticks that affect
Understand the clinical significance of mite and tick infestations
Be able to detect mite and tick infestations
Know how to collect mites from an animal
Know how to properly remove a tick from an animal
Be able to identify selected mite species
Be able to identify common tick species of Virginia
Understand the control and treatment of mite and tick infestations
Egg, larva, nymph, adult
Sarcoptes scabei, Sarcoptic mange, scabies
Notoedres face mange
Cheyletiella, walking dandruff
Brown dog tick
Wood tick, American dog tick
Lone star tick
One host, two host, three host
Mites and ticks are members of the order Acarina, so infestation with
either mites or ticks is referred to as
acariasis. Mites and ticks are not insects. Mites and ticks have only
two discernable body parts: a capitulum which is a head with
mouthparts, and the abdomen. The mouthparts are very prominent, it
almost looks like there is no head, just large mouthparts connected to
a big round abdomen. The mouthparts are used to suck blood or tissue
fluids. In some species the mouthparts are also used to attach to the
host. Adult acarines (mites and ticks) have 4 pairs of legs.
Mites and ticks are dioecious and produce eggs. There are four
developmental life stages: egg, larva, nymph, and adult. There is no
metamorphosis, but molting occurs that allows the organism to grow.
The larval and nymph stages appear to be miniature versions of the
adult. However, the larval stage has only 3 pairs of legs instead of 4
Mites and ticks can be ectoparasites of both animals and people,
depending on the species of parasite.
Mites are classified into various groups: Sarcoptiform,
nonsarcoptiform, and fur mites. Some of the legs of
these mites exhibit stalks with suckers on the end. The stalks are
called pedicels and may be
long or short, and jointed or unjointed. The
pedicel is an important feature to differentiate certain mite species
since some mite infestations are a reportable disease to the
Sarcoptiform mites are comprised of the Sarcoptidae
and Psoroptidae groups.
Sarcoptidae mites burrow into the skin of
the host, causing itching, dermatitis, and hair loss. They have big
oval abdomens and short stubby legs. Some of the legs exhibit long
stalks with suckers on the end. This group of mites includes Sarcoptes
scabei of dogs and Notoedres cati of cats. Also in this group are the
scaly leg mite of pet birds, Cnemidoptes pilae, and Trixacarus caviae
of guinea pigs.
Sarcoptes scabei is the causative agent of sarcoptic mange in dogs,
which is also called scabies. The mite comes in a variety of strains,
each infecting its own host species, however, the dog strain is the
most well known. While the mite may be fairly host specific, the dog
strain will temporarily infect humans. It causes a papular rash that
is very pruritic, which in humans resolves on its own in a few days.
In the dog, there is intense itching and hair loss, commonly seen on
the ear pinna, as well as on the elbows and ventral abdomen. A dog
that comes in for itching with hairless ears and an itchy human owner
is a common scenario with this mite. You must exercise extremely good
hygiene when working with these patients as this mite is very
contagious to other dogs.
You can’t really see this mite with the naked eye. You must perform a skin scraping of
the lesions and microscopically examine the scraping for mites and eggs.
Skin scrapings are done with a small surgical blade. Mineral oil is
applied first and the blade is held against the skin at an angle. The
blade is dragged across the skin in the same
several times to remove a few layers of skin cells and mites for
examination. Material will accumulate on one side
of the blade. The skin scraping should be deep enough to reach
the microscopic mite burrow, which means you need to cause a mild
abrasion with the side of the blade. You need to warn owners about
this before you do this. Scraping a lesion is a good site to test, but
also it is very useful to scrape those areas along the border of the
lesion, near normal regions. The scraped material is applied to a
slide with some mineral oil and a cover slip applied for examination
at the 10X lens objective. Look for the mite and eggs, which are oval.
If no sign of mites are found, several sites may be scraped before the
results are declared negative.
Sarcoptic mange lesion, photo courtesy of Sarah MacLaughlin
Sarcoptes scabei, photo courtesy of Sarah
Sarcoptes scabei, photo courtesy of
Notedres cati infects cats and rabbits. Notoedric mange is primarily a
dermatitis on the head and feet, which is nicknamed face mange. It is
possible for Notoedres to briefly infect humans, but it is not common.
The mite is collected via skin scraping.
For a set of photos about Notoedres cati, go to
Psoroptidae mites are found on the skin surface or in the external ear
canal. The entire life cycle is spent on the host and takes about 10
to 18 days. The activity of the mites, whether residing on the skin or
in the ear canal, cause pruritis and inflammation. When examining for
these mites, you may notice that the legs are a bit longer than those
of the sarcoptiform mites. The mites in this group include Psoroptes
cuniculi, Chorioptes spp, and Otodectes cynotis. All of the mites in
this group are spread by direct contact. For those mites that cause
otitis, sometimes the inflammation may be so severe as to cause
circling, head tilt, and balance problems.
Psoroptes cuniculi is the ear mite of rabbits, infesting the external
ear canal. It is also called the ear canker mite because the presence
of this mite causes the accumulation of dried crusts that build up to
an impressive amount. Chronic cases exhibit a build up of material in
the ear that can be seen protruding from the opening, and the debris
resembles corn flakes cereal packed in the canal. The activity of the
mite causes the animal to shake and scratch the head and ears. The
mite can be collected in the material from the ear, or by swabs. The
specimen is placed on a slide with mineral oil and cover slip for
microscopic examination at the 10X lens objective.
Clinical appearance of rabbit ear canker, photo courtesy of Sarah
For a photo of Psoroptes cuniculi mite go to slide
27 at this
Psoroptes infections of large animals are known as
"scab" or scabies. Psoroptes mites are fairly host specific. Psoroptes
ovis infects sheep, Psoroptes bovis infects cattle, and Psoroptes equi
infects horses. Infestations in sheep can be especially debilitating.
The Psoroptes mites all look very similar to other sarcoptiform mites,
but must be differentiated from other mites because Psoroptes
infections of large animals is a reportable disease. The pedicels of
the Psoroptes mites are long and jointed. See figure 13-53 on page 177
of your textbook.
An example of a Psorptes spp. mite, photo courtesy of Shawn Zimmerman
For more photos about Psoroptes mites in large
animals go to this website
Chorioptes spp mites are known as the itchy leg mite, or foot and tail
mite, because it tends to reside on the lower legs and sometimes the
tail of large animals. Pruritis and
dermatitis is present, with some noticeable scabbing. Examining skin
scrapings will reveal the mite. The Choroptes mite
resembles Psoroptes except that it has short unjointed pedicels.
Chorioptes spp mite, photo courtesy of Sarah
Chorioptes spp egg, photo courtesy of Sarah McLaughlin
Otodectes cynotis is the common ear mite of the dog and cat. There is
pruritis and otitis externa that causes the animal to shake his head
and scratch the ears quite enthusiastically. Sometimes the shaking and
scratching is so severe that a hematoma forms
in the ear pinna.
Using an otoscope, the mites can be seen as small specks with legs
scurrying about in the light of the scope. The exudate that
accumulates in the ear is brown and grainy, reminiscent of coffee
grounds. The mite can be collected via ear swabs and examined on a
slide with mineral oil under a cover slip. If you
don't see mites, look for the eggs on the slide preparation as another
indication that they are present. The 10X lens objective is
infection clinical appearance- dark brown wax accumulations, photo
courtesy of Kim Myers
Otodectes spp. mite, photo courtesy of Karen Marcus
Otodectes spp. mite eggs. Specimen courtesy of Jessica Lozada.
This group of mites includes Demodex spp, Pneumonyssoides, and some
Demodex mites live in the hair follicles and sebaceous glands. They
cause folliculitis, dermatitis, and hair loss.
Demodex mites are also sometimes observed in swabs from the external
ear canal. There can be secondary
bacterial infection of the skin and follicles. Demodex induced lesions
may be localized to small areas, or can be generalized to the entire
body. The lesions can be pustular, crusting, or merely erythematous.
In large animal species, the lesions may even be nodular and contain
caseous material. When Demodex infection is generalized, it is assumed
that the animal may have a problem with immunocompetence or stress.
Erythema may be pronounced, especially in dogs, and because of that,
the disease has been called red mange. A more common name for a
clinical infection with this mite is Demodectic mange.
example of a localized Demodectic mange lesion, photo courtesy of Kim
Generalized Demodectic mange lesions, photo courtesy of Jennifer
Demodex mites are detected via deep skin scrapings in lesions and
along the edge of the lesion. Recovery of the mite may be enhanced if
the area to be scraped is first gently picked up in a skin fold and
squeezed lightly in order to express the mite from the follicle. Then
the same skin area is scraped with a surgical blade on the surface
until a mild abrasion has occurred. For cats, it is recommended to
also scrape the area at the edge of the lesion on the normal side,
since this area may not have been as heavily groomed and mites maybe
are more numerous and more likely to be found. You will need to clip any
hair in the way from your scrape site before you scrape. The scraped material is
examined microscopically under a cover slip with mineral oil. The mite
is large enough to be easily seen at 10X lens objective. Material from
nodules, which may occur in large animals,
is usually collected by other means such as aspiration or lancing
techniques. Material collected form a skin scraping
can be very thick; be sure to spread the material thinly so the mite
is not hidden by heavy debris.
Each host has its own Demodex species of mite. Demodex is not
considered as contagious as some of the other mites, and is
considered zoonotic. It is transmitted by direct close contact,
usually by the mother to the young. There are a variety of Demodex
species, but all have a similar appearance. The adults are wormlike,
having elongated bodies and 4 pairs of short stubby legs. Many
technicians refer to them as little alligators, or cigars with faces.
The young larval stage has 3 pairs of legs. The eggs are spindle
shaped, see figure 13-58 on page
179 in your textbook. Some species of Demodex have quite long and thin bodies with a pointy tail end, while
other species may be short with a blunt end. Regardless, they are
somewhat colorless and may be mistaken for debris or skin flakes if
there is a lot of nondescript debris on the slide with them. You
may need to lower the condensor on your microscope to increase the
contrast to improve the visibility of this mite on skin scrapings.
Frequently changing your plane of focus is also important to make sure
you don't miss any mites.
Demodex. spp, photo courtesy of Sarah
Demodex spp. and debris, photo courtesy of Jean Holtzen
Other examples of Demodex spp
Another technique that is useful in detecting
Demodectic mites is to examine hair plucked from and at the edge of a
lesion, rather than scraping the area. The goal is to acquire the hair
root with accompanying sebaceous material and mites from the hair
follicle that cling to the root as it is removed. Pluck several hairs
at a time with an instrument such as a hemostatic forcep. Place the
hairs on the slide in a drop of mineral oil under a cover slip so that
all the hairs are oriented in the same direction. That way all the
root ends will be in the same general area for viewing . With this
technique, you will need to focus up and down on the material clinging
to the root to find the mites.
Hair pluck technique. A mite is easily seen here next to a hair in
this plane of focus. Specimen courtesy of Sonya Merriner, LVT
This is the same field as above, but a different plane of focus, The
mite previously viewed is no longer visible because it is out of
focus. However, a mite can be seen immersed in the material on the
root layered behind the dark hair.
Did you see it? The red arrow is pointing to the mite head and legs.
The other end of the mite body is seen below on the other side of the
Demodex mites may be found on normal animals but
will be present in very low numbers. When lesions are present, the
numbers of mites will be greater. Treatment of demodectic mange
requires repeated treatments over several weeks time in order to bring
the condition under control. Results can be disappointing. Initially,
scrapings or hair pluck preparations will demonstrate live moving
mites. Over the course of treatment, follow up skin scrapings or hair
plucks are performed. With effective treatment, any mites recovered
should be inactive, appear damaged, or dead. You may be asked to
determine the ratio of live vs. dead mites to help gauge the progress
of treatment during follow up.
Pneumonyssoides is the nasal mite of dog. It is rare but has gotten
more and more attention in the literature in recent years. They are
considered nonpathogenic but may annoy the dog and cause nose rubbing
and sneezing. They are large enough and active enough to be seen
around the nostrils sometimes by the owners. See figure 13-63 page 183
in your textbook.
Demanyssus gallinae is the red mite
of poultry, so called because of its appearance after a blood meal. D
gallinae is a periodic parasite in that it inhabits and reproduces in
the environment, and just visits the host for feeding at night.
Clinical signs of infestation with this mite include anemia, weight
loss, decreased egg production, and death. These mites may also bite
humans. The mites may be collected from the birds, nest litter, or
from cracks and crevices in the housing. If a pet
bird is infested, the mites can also be collected from the cage cloth
where they will tend to hide during the day.
Furmites and Feather mites
Furmites are surface dwelling mites associated with the hair
(or feathers) and top surface of the skin. The mites in this
group include the various furmite species of the dog, cat, rabbit, and
rodents. There are many, so the representative mite we will discuss is
Cheyletiella spp is a furmite that may affect dogs, cats, or rabbits.
Generally, the mites do not burrow much but stay on the surface
ingesting keratin flakes and some tissue fluids. They are also called
“walking dandruff” because they can be observed moving and resemble
specks of white skin flakes. In heavy infestations, the animal will
look like it has been dusted with baby powder. Animals undergoing
chemotherapy seem to be more likely to develop Cheyletiella
The Cheyletiella mites may be collected with a flea comb or with clear
cellophane tape applied to the hair and skin. Microscopic examination
reveals some interesting features about this mite. It has hooklike
accessory mouthparts which remind some technicians of a horned helmet.
The body shape is somewhat acorn like in that it is broader near the
For a photo of typical
Cheyletiella spp see figure 13-65 on page
185 in your text book or go to slide 9 at this site:
Treatment for any mite infestation depends on the species of mite, the
site in which it is residing, and the host. Many treatments are
repeated at regular intervals in order to break the life cycle. A
variety of topical medications and compounds have been used with
success for many types of mites. Often the environment needs to be
treated as well. The avermectin group of drugs has found use for
several types of mite infestations and has replaced pesticides in many
cases. However, generalized Demodectic mange is still a special
challenge and requires
repeated combination therapy of medicated
shampoos, as well as topical mitocides, or systemic mitocides, and
oral medication to address secondary bacterial pyoderma.
Treatment of food animals requires special precautions because of drug
residues. And remember some forms of mange in large animals are reportable to
the authorities. For a list of reportable diseases in Virginia see
Ticks are larger than mites but similar in overall shape. The
mouthparts are used for attachment and anchoring to the host and
sucking blood. Ticks are known to transmit many pathogenic organisms.
Some ticks are infected when feeding on an infected host and then pass
it on to another host they feed on later. In some diseases, the tick’s
ovary is actually infected and all the progeny from that infected
female are then infected from the very beginning of
life. This is known as transovarial transmission. They do not need to feed on an infected
host first in order to acquire and transmit a disease organism to
another host. Some tick species produce toxic saliva that is
associated with a clinical syndrome known as tick paralysis.
There are two main groups of ticks, argasid, or soft, ticks and ixodid,
or hard, ticks. Argasid ticks have a leathery body covering and the
mouthparts are on the ventral aspect of the body. Ixodid ticks have a
hard chitinous shell, or scutum, that is on the dorsal surface of the
body. The mouthparts of the ixodid ticks are more readily seen when
viewed from the dorsal aspect. Ticks move by crawling.
Comparison of soft tick on the left to the hard tick on the right. You
can see the mouthparts protruding out on the hard tick when viewed
from above. Photo courtesy of CDC.
Photo of soft tick showing that the mouthparts are on the ventral
surface of the body
Photo of a hard tick showing the mouthparts protruding from the end of
The life stage of the tick is the egg, larva, nymph, and adult. The
adult males are usually a little smaller than the females. After
feeding on the host, the adult female becomes engorged and drops off
the host. If you have ever seen an engorged female, you might wonder
how they can even move to find a safe place to lay the eggs, but they
somehow manage. The eggs are laid in the environment. The larval ticks
that hatch out are called seed ticks. They are quite small and have
six legs. The larva will feed on the host and molt to the nymph stage,
which now has eight legs. The nymph will feed on another host and molt
until it becomes an adult. The adult will then feed on the host again
and reproduce. The blood meal is required for reproduction. During the
life cycle, a tick species may only infest one host, or it may infest
up to three or more different hosts. Therefore, ticks may be
characterized as one host ticks, two host ticks, or three host ticks.
If they have more than one type of host, they seem to have preferences
for certain hosts at certain life stages. Although, most tick species
will feed on nontraditional hosts if needed.
Tick laying eggs. Photo courtesy of CDC
Group of three ticks showing various life stages. A "seed tick" or
three legged larval tick is on the far right. Photo courtesy of CDC,
Collection of various ticks. Even the same species of ticks will have a different size and
appearance depending on the life stage, sex, and time of blood meal.
Argasid ticks (soft ticks)
There are two argasid ticks of interest. The spinose ear tick and the
The spinose ear tick is usually found in the southwest United States.
This tick favors the external ear canal of many domestic animals. The
presence of the tick may be quite irritating to the animal and is
easily seen with an otoscope. The fowl tick
is the soft tick of poultry, feeding on them mostly at night. The
birds may become anemic and suffer decreased egg production.
Argus spp, the fowl tick
Ixodid ticks (hard ticks)
The Ixodid ticks of interest are Boophilus annulatus, Rhicephalus
sanguineus, Dermacentor variabilis, Amblyoma spp., and Ixodes
Boophilus annulatus is known as the Texas Cattle Fever tick and has
been eradicated from this country. It is the intermediate host for the
Babesia bigemina parasite of cattle. The tick is a one host tick,
spending the entire life cycle on cattle, and not leaving to find
another host. A cow infested with this tick will exhibit larvae,
nymphs, and adult simultaneously. Since this tick has been eradicated,
it must be reported to authorities if found. Usually, to find this
tick at all you would normally be in regions near the border with Mexico.
The common ticks of Virginia are nicknamed the American dog tick, the
lone star tick, the brown dog tick, and the deer tick:
Dermacenter variabilis is the American dog tick, also known as the
wood tick. This tick is dark brown and has distinct white stripes on
its dorsal surface. When engorged the female is huge, about 12 mm and
a blue gray color. It is a three host tick; the hosts may include
various rodents, dogs and humans. This tick is best known as a vector
of Rocky Mountain Spotted Fever, but transmits many other diseases.
Dermacentor, the American dog tick (wood tick), photo courtesy of CDC
Amblyomma americanum is the lone star tick so called because of a
distinct white spot in the center of its dark dorsal surface,
resembling a star. It is a three host tick that uses a variety of wild
and domestic hosts, including humans. This tick transmits Rocky
Mountain spotted fever and other diseases.
Amblyomma americanum, the lone star tick, photo courtesy of CDC, Michael
Rhipicephalus sanguineus is the brown dog
tick. This tick is a plain brown tick that prefers dogs. This tick
will not only inhabit the outdoors but will also will invade household
or kennel environments and become established indoors! The engorged
tick is a gray color. This tick is known to transmit Babesia canis and
Rhipicephalus, the brown dog tick, photo courtesy of CDC
Ixodes scapularis (dammini) is known as the deer tick and is famous for
transmitting Lyme’s disease. It is a three host tick that normally
feeds on mice and voles in the larval and nymph stages, and then on
the white tailed deer as adults. The white footed mouse is the
reservoir for Lyme’s disease and is the host that infects the tick
population. The deer tick is difficult to detect because it is so much
smaller than the other species of ticks. The other ticks found in
Virginia average about 5 mm in length as adults when not engorged.
However, the deer tick is only about 2 mm in length with long
mouthparts. The larva and nymphs are even smaller and so are often
missed during inspections for ticks. This tick is a reddish brown
color and has black legs.
Ixodes, the deer tick, photo courtesy of CDC, Michael Levin
Ticks are most active during the spring, summer, and fall months.
Ticks attach to the host and remain there for a few days sucking blood
before they leave for the next life stage. When found attached, ticks
should be removed with either gloved hands, a kleenex type tissue,
tweezers, or forceps. If the tick releases any fluids while it is
removed, the fluids may contain infectious agents, hence the
recommendation for gloves or instruments while handling ticks. The
ticks should be grasped as close to the skin as possible and pulled
off without twisting, hopefully with the head intact. If any
mouthparts are left behind, they may cause a localized tissue reaction
later. After removal, the area can then be cleansed or swabbed with
disinfectant. It is important to remember that ticks need to be
attached for several hours or more before they can transmit any
tickborne disease, so if ticks are not allowed to remain on an animal,
the risk of tickborne disease is decreased. A general guideline is to
check for ticks every four hours when outdoors. Many people have
devised a variety of unnecessary methods to remove ticks, such as
using nail polish, petrolatum, or alcohol. A favorite one is to apply
a lit match to the tick to encourage it to detach and move so that it
can be collected off of the host. This is not necessary and should be
discouraged for obvious reasons, one of which is that the host may get
burned. A myth that occurs about ticks in some circles is that if any
parts of the head are left in, the tick will grow back. This is not
true, and is probably an extrapolation that
is borrowed from the information about tapeworms.
A habit some people have is to crush ticks between the fingernails
after removal. This activity should be discouraged for a variety of
reasons, but particularly because the tick body fluids potentially
contain infectious agents. Instead, the ticks should be killed in
rubbing alcohol and kept in a vial for a few months in case any tickborne disease develops, in which case it would be needed for
Treatment for tick infestations includes mechanical removal and
pesticides. Repellants are sometimes also used to
prevent tick attachment when going outdoors.
Websites of interest
Graphic images of
parasites listed in various ways- go to look at the one you want
mite image collection
Lesson 11 Writing assignment
- T or F Sarcoptic mange in dogs can be
- Let’s pretend. I am a client and you are going
to perform a skin scraping on my dog to rule out mange mites. What
are you going to tell me to expect about the procedure?
- T or F Sarcoptes mange mites are not very
contagious and require close and prolonged intimate contact.
- Mange mites are collected by what method?
- Furmites are collected by what method?
- Ear mites are collected by what method?
- The Genus of the ear mite of small animals is
- What special recommendation is given for
collecting Demodex mites from cats?
- What is the proper technique for removing
- What tick infestation would require treatment
of the indoors?
- Why is generalized Demodectic mange difficult
- Which tick is so tiny its presence could be
missed, and is known to transmit Lyme’ disease?
- What is transovarial transmission and why is
- T or F If you leave a part of the tick head
in the animal after removal, the tick will grow back.
- Which tick is reportable to authorities?
- Which tick has a pretty white spot
in the middle of its back?
17. How often should you check for ticks when
18. Which tick could be active during the
19. Which mite infestation is reportable to
20. When is the best time to collect many of the
mite or tick species from poultry?
21. So if a pet bird has the clinical appearance
of a mite infestation, but you can't find evidence of the mite on the
bird, where else could you look?
22. What are chiggers?
23. Let's pretend. Your college housemate has a
pet hamster that has little teeny tiny bugs crawling on it and in its
cage and bedding. Some of the bugs that are attached to the hamster
have a reddish brown color like little ticks. Your housemate complains
of an itchy rash on her back and notes that there are the same little
bugs on her sheets. She thinks she and the hamster caught them from
her boyfriend. What is the most likely explanation and how would you
collect the "bugs" for examination?
Bowman DD, Lynn RC, and Eberhard ML: “Georgi’s Parasitology for
Veterinarians” Saunders, Philadelphia, 2003, pp 48-76
Virginia Cooperative Extension. Entymology Fact Sheet “Common ticks of
Virginia”, publication 444-271, 1997. can be found
Samples OM: "What you should know about Tick-Borne
Diseases" Veterinary Technician may 2003, pp.314-322
Many thanks to the Public Health Image Library of
the CDC for photos
Many thanks to the Veterinary Technician Educators,
Hill's Pet Nutrition, and Jennifer Birchem, LVT for other photographs
Many thanks to Sonya Merriner, LVT for demodex hair