Unit U: Background Information
Unit U: Parasitology
Reading Integration:
Complete the Pre- and Post-Vocabulary Assessment.
Reading Integration:
Stump the Teacher: Students and the instructor should read about parasitology
to themselves. Next, students should try to think of questions to try to stump the
instructor. Their questions should be about the content and not along the lines of
“What is the fourth word on page 2?”
Background Information
Parasites are one of the most prolific types of organisms in the world. A parasite is
an organism that lives within or on another organism. The organism that the parasite lives
off of is called the host, and the parasite is dependent on its host. The parasite may harm
the host organism but usually does not kill it. This is a type of symbiotic relationship.
Parasites can include many types of organisms: animals, viruses, bacteria, fungi and plants.
Parasites can infect every living thing on earth, including other parasites. They can cause
significant harm to animals and humans by spreading zoonotic and vector-borne diseases.
Parasites can cause economic losses in the livestock industry, including decreased efficiency,
increased time to market weight, and decreased carcass value.
Kinds of Parasites
Parasites are classified as endoparasites, living inside the animal, or ectoparasites,
living outside the animal. Endoparasites can produce an infection within the host animal and
cause damage by absorbing food intended for the host, drawing blood and lymph fluid,
damaging tissue and causing internal bleeding, creating obstructions in the intestines and
circulatory system, and producing toxins. Ectoparasites produce an infestation on the host
animal that can cause irritation to the skin, restlessness and worry, the transmission of
infectious organisms, and the drawing out of blood.
Parasites can also be classified by their physical characteristics and scientific name.
There are only two kingdoms that have organisms that are true parasites of domestic
animals -- Kingdom Animalia (platyhelminths, nematodes, acanthocephalans, annelids and
arthropods) and Kingdom Protista (protozoans).
Background Background
Unit U: Background Information
Endoparasites come from both Kingdom Animalia and Kingdom Protista. Common
endoparasites are roundworms, flatworms, thorny-headed worms, tapeworms and protozoa.
Ectoparasites come only from Kingdom Animalia. Common ectoparasites include mites, ticks,
mosquitoes and flies.
A dichotomous key is a tool used to identify plants or animals through a set of
characteristics. It is also helpful in identifying parasites according to their characteristics.
Each step in the key has two distinct options and directs the user to a new step until the
object is identified. This is a useful tool for scientists, veterinary staff or producers to identify
a parasite that they do not know. It is important to properly identify the parasite, so that the
animal can be treated effectively.
Life Cycles of Parasites
A parasite matures through a set of stages throughout its life, and every parasite has
its own unique life cycle. All parasites have a definitive host, and some parasites may have
more than one definitive host. Many also have an intermediate host or hosts. An
intermediate host can be classified as a paratenic, or transport host, if the parasite is
dormant within that host. The parasite becomes active again only when its definitive host
eats the paratenic host. A parasite that only has a definitive host is said to have a direct life
cycle. A parasite that has one or more intermediate hosts has an indirect life cycle.
Most ectoparasites go through metamorphosis, a series of changes throughout their
life cycles. Some species go through complete metamorphosis which has four stages:
Egg
Larvae
Pupa
Adult.
Other species go through incomplete metamorphosis, which has three stages:
Egg
Nymph
Adult.
Endoparasites also have immature and adult stages to their life cycle. Most
endoparasites develop partially outside of the definitive host before they infect it. There are
four major ways that internal parasites infect definitive hosts:
1) direct ingestion
2) eating an intermediate host
Background
Unit U: Background Information
3) penetrating the definitive host
4) maternal transmission.
Controlling Parasites
It is important to have a good understanding of parasite life cycles because some
parasites can only be treated in certain stages of their life cycles with certain specific
treatments. Other parasites are only treated effectively by removing an intermediate host.
Many parasites are specific to one type of animal and are considered homoxenous.
Parasites adapt to be able to affect a specific host. The host and the parasite often evolve
together. The host may develop immunity or adaptations to evade the parasite. In turn, the
parasite will then develop new mechanisms to affect the host. Parasites also have strategies
to evade a host’s defense mechanisms. The host of a parasite that only occasionally affects
another species of animal is called an incidental host.
There are many factors that affect how host specific a parasite is. These include the
following:
The host must share the same environment as the parasite.
The host must be exposed to the parasite as part of its normal behavior.
The host must be recognized by the parasite via secretions, surfaces or
membranes.
The host must be able to meet nutritional requirements of the parasite.
Within a particular host species, a parasite may also have a preferred type of
organism with which it establishes a relationship. Young and old animals; pregnant and
lactating animals; malnourished, stressed or immune-compromised animals are more
susceptible to parasites, due to immature or weakened immune systems. Host animals that
are resistant to the parasite help to strengthen the genetics of the host population.
Just as parasites can be host specific and impact a certain species of animal, they can
also be regionally specific and thrive in a certain environment. A parasite creates a niche or
place in its ecosystem where it can obtain resources and survive. A parasite is considered
endemic if it is continually found within a population of animals in a specific region.
Enzootic is another term for this phenomenon.
There are many reasons why parasites are often limited to certain regions. The
parasite has to be able to complete its life cycle in a certain environment. Parasites may be
able to survive inside of a host or on a host in a particular environment, but if the
Background
Unit U: Background Information
conditions are not right for the parasite to complete the part of its life cycle that is not on
or in a host, it will not be able to survive in that environment. Prevalence of parasites in any
given region is dependent on the presence of definitive and intermediate hosts, weather
conditions and climate.
Transmitting Parasites
A vector is a living organism that carries a parasite and transmits it to another
organism. A vector can be strictly mechanical and just transmit the parasite, or if it serves as
a true intermediate host, it may be a necessary part of the parasite’s life cycle. A vehicle is a
non-living thing that spreads a parasite. Ectoparasites serve as vectors for many other
parasites, bacteria, viruses and fungi. Common vehicles that spread parasites include food,
water, feces and blood. Another type of vehicle is called a fomite. A fomite is an inanimate
object that a parasite can live on until it is picked up by a host. Even clothing and bedding
that may be contaminated with infectious organisms can serve as fomites in the
transmission of parasites.
Internal parasites often need some sort of vector or vehicle within their life cycle to
spread their infective stage to new hosts. The adult stage of the internal parasite does not
typically survive outside of the host. One strategy that is used by parasites is transmission in
a predator-prey situation. The parasite is released into the environment and ingested by a
prey animal that is a herbivore. This prey animal is a reservoir host or an intermediate host.
When the predator eats a prey animal that is infected, the parasite is transferred to the
definitive host.
An additional way that a vector can transmit a parasite is through blood contact.
When an animal, such as a mosquito, feeds on blood, it becomes an intermediate host and
transmits a parasite from one host to the next. Sometimes the parasite can live inside this
intermediate host for a period of time before being transmitted to the next definitive host.
Reading Integration:
Complete the Inquiry Chart about parasites.
1. Reference the Inquiry Chart found at the end of Background Information.
Students will be given sources or instructed to research them.
a. There are questions in columns across the top.
b. Each row corresponds with a particular source.
c. The last row is a general summary of each question.
Background
Unit U: Background Information
2. After reading the Critical Questions in the header row, students should assess
what they already know about each question.
3. Then students explore the topics through questions in the columns. For each
source or text, they answer questions based on the source or text.
4. At the bottom, students compile all they have discovered into a coherent
summary statement to answer each question for the topic in general.
Controlling Parasites
Animals are treated with antiparasitic drugs to control parasite infections and
infestations. Antiparasitic resistance is the ability of parasites to survive a treatment of an
antiparasitic drug to which they had been susceptible in the past. This ability is genetic and
can be a problem when a large percentage of parasites affecting the animal carry the
resistant gene. These parasites can then survive a treatment that was previously effective.
When an animal is treated with antiparasitic drugs, a certain percentage of the
parasites will survive the treatment because they are genetically resistant to the drug. The
resistant parasites then breed with each other and pass on those resistant genes to their
offspring. If there are not a lot of susceptible parasites left, then the population will become
more resistant and will no longer respond to the antiparasitic drug.
When animals are treated for parasites, there is a certain percentage of the
population of that parasite that is not affected. This could be parasites that are living in or
on untreated animals, eggs and larva that are in the environment, or life stages of the
parasite that are not affected by the treatment drug. These parasites are called refugia or
parasites that are not selected for treatment. These unaffected parasites have not developed
resistance, because they were not exposed to the antiparasitic drug.
There are many things that increase antiparasitic resistance. The genetics of the
parasite, how it lives, and its pathogenicity can increase resistance. The immune status of the
host, frequency of treatment, mechanism of action of the drug, and overall animal
management factors can also have an effect.
Internal parasites often have to be identified by examining a fecal sample using a
microscope. There are several methods for preparing a fecal sample for diagnosis. They
include the following:
Direct smear, in which a small amount of feces is placed on a slide and examined
under a microscope
Background
Unit U: Background Information
Fecal flotation, a procedure that uses specific gravity to allow parasite eggs, cysts,
and larvae to float to the top of a solution
Fecal sedimentation, which separates out parasite eggs that have so high a
specific gravity that it would be difficult to make them float.
Blood samples and skin scraping can also serve as diagnostic tools.
Parasites have a symbiotic relationship with their hosts. These species have co-
evolved over time and the hosts must develop new strategies to prevent the parasites from
impacting them. Parasites must get past the host’s defense systems in order to be able to
feed. Each time a new host defense strategy evolves, the parasite develops a strategy to
counter it. Over time these animals have developed a complex relationship of attack and
defense mechanisms.
Innate defenses are host defenses that naturally occur and prevent any harmful
organism from entering their systems. Hosts have a large variety of innate defenses that are
utilized to protect themselves against parasites and keep parasite levels in check. These
include the following:
Beneficial bacteria
Low pH is specific areas of the body (i.e. stomach)
Enzymes in saliva
Peristalsis in the intestines that keep substances constantly moving
Keratin, a protein particle in skin, that prevents parasites from entering
Sebum, produced by sebaceous glands and is toxic to some invaders
Mucus membranes
Macrophages, cells in the lungs that engulf and destroy microorganisms
It is acceptable for some animals to have a small number of parasites or worms living
in their body symbiotically. However, if the defenses of an animal’s body are worn down, or
if the animal is immune compromised or unhealthy for any reason, a parasite may increase
in numbers. If the parasite load becomes too high, the animal will begin to show negative
effects of the parasite invasion. Treatment to eliminate or reduce the parasite load should
occur immediately if parasites are negatively impacting the animal.
Background
Unit U: Background Information
Name_____________________________________
Pre/Post Vocabulary Assessment for Parasitology
For each term listed below, first complete the “Pre” column. If you have never heard of the
word or concept, write a – (minus) in the column. If you have heard of the word or concept,
write a (check) in the column. If you have heard of the word or concept and could carry
on a quasi-expert conversation using it, write a + (plus) in the column.
Pre Term Post
Parasite
Host
Zoonotic disease
Endoparasite
Ectoparasite
Metamorphosis
Homoxenous
Vector
After the lesson, you will reassess your knowledge of these important terms related to
parasitology by using the same marking system. This time, mark the “Post” column.
Background
Unit U: Background Information
Name_____________________________________
Parasites Inquiry Chart Critical Question #1:
What are some of the best
methods of controlling
parasites?
Critical Question #2:
When is the appropriate
time to apply medicine to
control parasites?
Critical Question #3:
What is the role of
sanitation in parasite
control?
What I think
I know
Source #1
Source #2
Source #3
Summary of
Information
Background
Unit U: Answer Keys
Unit U Answer Keys:
Lesson Post-test Answers
U.1.1 1. C 2. B 3. A 4. D 5. A
Answer Keys
U.1.1: Instructor
U.1.1 Parasite Sleuth
Pre-Lesson Preparation:
U.1.1 PowerPoint® Presentation: Parasite Identification (Blank-NOT the Answer
Key) needs to be printed in color for students to utilize. Slides can be cut into cards
or used full size. Students may complete this on a computer to save paper.
Materials:
U.1.1 Student Activity Directions
U.1.1 Student Handout 1: PowerPoint® Notes: Parasite Identification
U.1.1 Student Handout 2: Endoparasite Dichotomous Key
U.1.1 Student Handout 3: Ectoparasite Dichotomous Key
U.1.1 Student Handout 4: Parasite Sleuth
U.1.1 Evaluation: Parasite Sleuth
U.1.1 Post-test Questions: Parasite Sleuth
U.1.1 PowerPoint® Presentation: Parasite Identification
*This item needs to be printed in color for students to utilize. Slides can be cut into
cards or used full size. Additionally, students may complete this on a computer to
save paper and colored ink.
U.1.1 PowerPoint® Presentation: Parasite Identification Answer Key
Pencil one per student
Goals:
Skill: Use a dichotomous key to identify parasites.
Content: Identify common parasites of animals.
Terminology:
Classification: the organization of things based upon shared characteristics
Key Point:
Parasites can be identified by their physical
characteristics.
Instructor
U.1.1: Instructor
Dichotomous key: a tool for identification that involves a series of choices a user
works through until the object is identified
Ectoparasite: a parasite that lives on the outside of a host
Endoparasite: a parasite that lives within a host
Host: an organism that a parasite is dependent on; a plant or animal that a parasitic
or commensal organism lives on or in; an organism that provides nourishment
and/or shelter for a parasite
Parasite: an organism that lives in or on another organism and benefits at the
expense of the host organism
Parasite infection: disease caused by protozoan parasites
Parasite infestation: disease caused by arthropods and worms
Taxonomy: the science of classifying organisms
Zoonotic: describing a disease that can be passed from animals to humans
Question to Consider:
What traits are used to help differentiate parasites from one another?
Procedure:
1. The instructor will present the Question to Consider for writing or discussion.
2. Direct students to U.1.1 Student Handout 1: PowerPoint® Notes: Parasite
Identification.
3. The instructor will present U.1.1 PowerPoint®: Parasite Identification while students
follow along and complete U.1.1 Student Handout 1: PowerPoint® Notes: Parasite
Identification.
4. Direct students to U.1.1 Student Handout 2: Endoparasite Dichotomous Key, U.1.1
Student Handout 3: Ectoparasite Dichotomous Key, and U.1.1 Student Handout 4:
Parasite Sleuth.
Instructor
U.1.1: Instructor
5. Students should work in pairs to complete the U.1.1 Student Handout 4: Parasite
Sleuth activity. Each pair should be given a set of U.1.1 Parasite Identification slides
or cards that have been printed or copied ahead of time (U.1.1 PowerPoint®:
Parasite Identification cards printed from slides.)
6. Instructor will utilize U.1.1 PowerPoint® Presentation: Parasite Identification Answer
Key to review answers.
Assessments:
U.1.1 Evaluation: Parasite Sleuth
U.1.1 Post-test Questions: Parasite Sleuth
Additional Resources:
Local veterinary offices may have preserved parasite specimens for students to
view and identify. Specimen slides or mounts for endoparasites and ectoparasites
may also be purchased from Ward’s Science or another science supply company and
utilized in place of the pictures.
An extension to the above activity would be to allow students to create their
own dichotomous keys for parasites.
For additional information, see Laboratory Identification of Parasitic Diseases
of Public Health Concern at http://www.cdc.gov/dpdx/az.html
References:
Hendrix, C. M. (1998). Diagnostic Veterinary Parasitology. St. Louis, MO: Mosby Inc.
National FFA Organization. (2013). Veterinary Science Career Development Event
Manual. Retrieved from
https://www.ffa.org/SiteCollectionDocuments/cde_vetscience.pdf
Parasites of Dogs, Cats, Horses and Livestock: Biology and Control. (n.d.). Retrieved
Sept. & Oct., 2016, from http://parasitipedia.net/index.php?option=com_
content &view=article&id=2391&Itemid=2654
Instructor
U.1.1: Student Activity
U.1.1 Student Activity: Parasite Sleuth
Purpose:
Parasites affect all types of animals, and they are found all over the world.
Identifying parasites is the first step to controlling them. A dichotomous key is a
helpful tool in identifying common parasites of domestic animals.
Know and Do:
Use a dichotomous key to identify parasites.
Identify common parasites of animals.
Terminology:
Classification: the organization of things based upon shared characteristics
Dichotomous key: a tool for identification that involves a series of choices a user
works through until the object is identified
Ectoparasite: a parasite that lives on the outside of a host
Endoparasite: a parasite that lives within a host
Host: an organism that a parasite is dependent on; a plant or animal that a parasitic
or commensal organism lives on or in; an organism that provides nourishment
and/or shelter for a parasite
Parasite: an organism that lives in or on another organism and benefits at the
expense of the host organism
Parasite infection: disease caused by protozoan parasites
Parasite infestation: disease caused by arthropods and worms
Taxonomy: the science of classifying organisms
Zoonotic: describing a disease that can be passed from animals to humans
Student
Key Point:
Parasites can be identified by their physical
characteristics.
U.1.1: Student Activity Directions
Materials:
U.1.1 PowerPoint® Presentation: Parasite Identification (cards or sheets)
U.1.1 Student Activity Directions
U.1.1 Student Handout 1: PowerPoint® Notes: Parasite Identification
U.1.1 Student Handout 2: Endoparasite Dichotomous Key
U.1.1 Student Handout 3: Ectoparasite Dichotomous Key
U.1.1 Student Handout 4: Parasite Sleuth
U.1.1 Evaluation: Parasite Sleuth
Pencil (– one per student)
Procedure:
1. Respond to the Question to Consider as directed by your instructor.
2. Follow along and fill in U.1.1 Student Handout 1: PowerPoint® Notes using
U.1.1 PowerPoint® Presentation: Parasite Identification and PowerPoint®: Parasite
Identification cards or sheets from the slide presentation.
3. The instructor will break students into pairs. Complete the Parasite Sleuth activity
on U.1.1 Student Handout 4: Parasite Sleuth together. You will also need U.1.1
Student Handout 2: Endoparasite Dichotomous Key and U.1.1 Student Handout 3:
Ectoparasite Dichotomous Key.
5. Utilize U.1.1 Student Handout 4: Parasite Sleuth to record your results. The
instructor will provide you with parasite ID slides or cards to identify the parasites.
6. Review the correct identification of the parasites with your instructor utilizing the
PowerPoint®: Parasite Identification Answer Key.
7. Complete U.1.1 Evaluation: Parasite Sleuth if requested by your instructor.
Student
U.1.1: Student Handout 1
U.1.1 Student Handout 1: PowerPoint® Notes
Parasite Sleuth Symbiotic Relationships:
Predator-Prey:
Mutualism:
Commensalism:
Parasitism:
Parasite Scope:
Any living thing can be infected by a ______________, including other _______________.
Parasites are one of the most prolific types of organisms in the world.
Parasites cause huge economic losses to ____________ _____________ each year.
Parasites spread ______________ ______________
Classification: Endoparasites: Exoparasites:
Examples:
Damage: 1)
2)
3)
4)
1)
2)
3)
4)
Student
U.1.1: Student Handout 1
Classification of Parasites
Common Name versus Scientific Name
Carl Linnaeus
D______________
K_______________
P________________
C________________
O_______________
F________________
G________________
S________________
Classification of Parasites
Two Kingdoms have organisms that are true parasites to domestic animals
Kingdom ____________
Kingdom ____________
Ectoparasites
Kingdom Animalia (mites, _______, mosquitoes, and _______)
Endoparasites
Kingdom Animalia (___________, flatworms, thorny-headed worms, and
_____________)
Kingdom _________ (protozoa)
* Protozoan parasites are __________________
Dichotomous Key:
Student
U.1.1: Student Handout 2
U.1.1 Student Handout 2: Endoparasite
Dichotomous Key Parasite Sleuth
1. Life Stage
a. Adult/worm like – go to 2
b. Immature (Egg or segment) – go to 13
2. Type
a. Multicellular animal – go to 3
b. Unicellular protozoan – Giardia
3. Body Shape
a. Adult is flattened – go to 4
b. Adult is rounded – go to 6
4. Segmentation
a. Adult is segmented – go to 5
b. Adult is not segmented – Liver Fluke
5. Intermediate Host
a. Rabbit – Taenia Tapeworm
b. Flea – Dipylidium – Flea Tapeworm
6. Preferred Tissue
a. Adult lives in tissue outside of the gastrointestinal tract – go to 7
b. Adult lives in the gastrointestinal tract – go to 9
7. System Specialization
a. Parasite most commonly affects the circulatory system of dogs – go to 8
b. Adult is most often found in terminal bronchioles of the respiratory system
- Lungworm
8. Size and Scale
a. Parasite is found in the right ventricle and arteries – Adult Heartworm
b. Parasite is found throughout the blood in the circulatory system –
Heartworm Microfilaria
9. Digestive Organ Specialization
a. Small intestine – go to 10
b. Other organ – go to 11
Student
U.1.1: Student Handout 2
10. Mouth Opening
a. Teeth attach the worm to the intestinal wall where it sucks blood –
Hookworm
b. Large lips and small teeth to feed on intestinal contents – Roundworm
11. Egg Laying
a. Adult females lay eggs on exterior of the body – Pinworms
b. Eggs are laid internally and excreted in feces – go to 12
12. Shape and Size
a. Uniformly cylindrical worm – Horse Strongyles
b. Worm with anterior small and filament like with thick posterior –
- Whipworm
13. Egg or Segment
a. Egg – go to 15
b. Segment – go to 14
14. Pores
a. Single lateral pore present – Taenia Tapeworm Segment
b. Double lateral pores present – Flea Tapeworm Segment
15. Group of Eggs
a. Eggs in packets – Flea Tapeworm Egg
b. Eggs single - go to 16
16. Shell
a. Thick walled - go to 17
b. Thin walled - go to 18
17. Round or Oval Thick-walled Egg
a. Small, smooth, striated – Taenia Tapeworm Egg
b. Large and rough – Roundworm Egg
18. Thin-walled Egg
a. Morulated (larvated) embryo – Hookworm Egg
b. Single or double-celled embryo - go to 19
19. Single or Double-celled Embryo and Oval, Thin-walled Shell
a. Bilateral polar plugs, football shaped – Trichuris
b. Small (round to oval) - Coccidia
Student
U.1.1: Student Handout 3
U.1.1 Student Handout 3: Ectoparasite
Dichotomous Key Parasite Sleuth
A. Adult Body Type
a. Segmented with six legs… go to B
b. Unsegmented with eight legs… go to K
B. Insects
a. Adult… go to C
b. Immature (wormlike)… go to G
C. Adult insects
a. Wingless… go to D
b. With wings… go to F
D. Fleas and Lice
a. Body compressed (flattened) dorsoventrally… go to E
b. Body compressed laterally… Flea
E. Lice
a. Head narrower than body… Sucking Louse
b. Head wider than body… Biting Louse
F. Color and Size
a. Iridescent blue or green body… Blow Fly
b. Very large and beelike, hairy body… Horse Bot
c. Very small with long legs and proboscis… Mosquito
G. Larval Insects – Hair
a. No hair… Blow Fly Maggot
b. Hair… go to H
H. Larval Size
a. Larva .25 cm. to .5 cm… go to I
b. Larva 2.5 cm. or more… go to J
I. Larva Environment
a. Larva found in water… Mosquito Larva
b. Larva found in dry environments where animals live… Flea Larva
Student
U.1.1: Student Handout 3
J. Larval Color
a. Black and spiny segments… Cat Warble
b. Cream to dark brown and spiny… Cattle Grub
K. Arachnids
a. < 1 mm… go to L
b. > 1 mm… Ticks
L. Mites
a. Round or oval… Go to M
b. Cigar-shaped with short legs… Demodectic Mite
M. Mites
a. Oval with short legs and long pedicels… Sarcoptic Mite
b. Oval with long legs and short pedicels… Ear Mite
Student
U.1.1: Student Handout 4
U.1.1 Student Handout 4: Parasite Sleuth Parasite Descriptions
Name:
Directions: Work with your partner to identify the parasite pictures using the
dichotomous keys given to you. After you have identified the parasite, list some
descriptive characteristics of the parasite in the second box.
Number: Parasite Name: Description:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Parasite ID
U.1.1: Student Handout 4
Name:
Number: Parasite Name: Description:
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Parasite ID
U.1.1: Evaluation
U.1.1 Evaluation: Parasite Identification Parasite Sleuth
Name:
Identify the parasites below:
1.
2.
3.
Evaluation
U.1.1: Post-test
U.1.1 Post-test: Parasite Sleuth Name:
1. Giardia, a parasite that is a protozoan, is classified in which Kingdom?
A. Kingdom Plantae
B. Kingdom Animalia
C. Kingdom Protista
D. Kingdom Fungi
2. A type of parasite (e.g., tapeworm, roundworm) that causes infection inside an
animal is considered a/an ___?___.
A. Insect
B. Endoparasite
C. Ectoparasite
D. Vector
3. Which of the choices is an example of an ectoparasite?
A. Mites
B. Hookworm
C. Pinworm
D. Tapeworm
4. The level of classification that is the most specific in our system of taxonomy
is ___?___.
A. Kingdom
B. Phylum
C. Class
D. Species
5. A parasite that draws blood, irritates the skin, and causes restlessness is most
likely a/an
A. Ectoparasite
B. Endoparasite
C. Helminth
D. Vector
Post-test
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