1. Kingdom Animalia Pima Medical Institute Veterinary Technician Program
VTT 200-General Sciences—Biology

2. Characteristics of Animalia
Complexity increases moving from Phylum to Phylum per the handout overview
All are eukaryote
All are multi-cellular
All utilize Heterotrophic mode of nutrition
Most animals store sugars and fats, as opposed to plants which store starches and cellulose

3. Characteristics of Animalia
Animals have centrioles for cell division and lysosomes for breaking down enzymes; lower forms do not
Animals are predominantly sexual reproducers, but many still reproduce asexually
95% of all Animals are invertebrates (with no backbone)

4. Lowest Phyla Porifera: Sponges
No true tissues, no epithelial vs. muscle vs. connective, etc. as in higher animals
Sponges are all the same tissue type
No digestive tract, no nervous tissue
These were the transition organisms from fungi and plants to Kingdom Animalia

5. Lowest Phyla Cnidaria: Jellyfish, Coral & Sea Anenomes
Development of some tissue formation between the main “body” of the organism and tentacles or other parts

6. Lowest Phyla
Not as complex as higher animals, but certainly more complex than sponges
Comb Jellies: A small phyla not important for our veterinary study

7. Phylum Platyhelminthes: Important to veterinary medicine
Known as Flatworms: “Platy” means flat
“Helminthes” refers to worms
Anti-worm drugs are known as antihelminthes
Have definite tissues and very simple life cycle
First to show Bilateral Symmetry, where one side mirrors the other side
(Jellyfish are too abnormally flexible to have such symmetry)

8. Phylum Platyhelminthes: Important to veterinary medicine
Almost all are parasitic needing a host
Most are hemaphroditic
What does this mean?
Very simple nerves run through body—animal is responsive to stimuli

9. Phylum Platyhelminthes: Important to veterinary medicine
Three very important classes:
Cestoda and Trematoda important for veterinary parasitology
What are the Cestodes? What are the Trematodes
Class Tuberellia (carnivorous fresh-water worms of 2cm or less—not important for vet medicine)

10. Phylum Platyheminthes: Class Cestoda
Cestoda (tapeworms)
All parasitic residing in the intestines of their host
Transmitted by fecal-oral transmission—ingestion of eggs
Segments are shed in feces each carrying hundreds of eggs
Larva often vectored by flea

11. Phylum Platyheminthes: Class Cestoda
Cestoda (tapeworms)…
3 main Genus/ species
Dipylidium caninum
Taenia pisiformes
(common cat & dog tapeworms)
Echinoccus is a very zoonotic tapeworm that can migrate to the throat, eye, and eventually the brain

12. Phylum Platyheminthes: Class Trematoda
Trematoda (flukes)
Not really a worm at all; more closely resembles a leech
Simple life cycle, but often found throughout body: lungs, liver, kidney, bladder, throat, muscles, even occasionally in brain
Can grow large and be very invasive to host
Not often found in Las Vegas Valley because have requirement for moist swamp like environments
More of a problem in large animals

13. Phylum Rotifera Not important to our study
However, important toxonomically because these are the first animals that show the presence of body cavities
These are non-parasitic fresh water worms with a pseudo-abdominal cavity with some slight demarcation from rest of tissue

14. Phylum Nematoda: EXTREMELY IMPORTANT
Roundworms (with many classes and forms)
Have true tissues and an obvious abdominal body cavity, but without a Mesoderm (interior lining)
Have obvious round shape and bilateral symmetry
Have simple nerves running through body making worm responsive
Reproduce Sexually with male and female

15. Phylum Nematoda
More complex life cycle often with intermediate hosts and a larval stage that migrates from certain parts of the body to the lungs—larva is then coughed up and swallowed into the intestines
However, many of these roundworms can settle in various parts of the body: liver, lungs, kidney, bladder, gums, tongue, eye, nasal passages, brain, blood, etc.
Roundworms are the most abundant worm on earth

16. Phylum Nematoda (Roundworms)
NOTE: We will not review actual classes per taxonomy, but will review them by groups:
Ascarids
Hookworms
Whipworms
Threadworms
Heartworm

17. Nematoda: Ascarids Predominantly intestinal roundworm
Commonly passed in mother’s milk to young puppies and kittens
Most common worms of neonates
Thick cuticle to avoid attack by gastrointestinal juices
Females can lay thousands of eggs/ day

18. Nematoda: Ascarids Most common veterinary parasites:
Genus Toxocara (with many species specific to certain animals: T. cati; T. canus; T. leonina
Genus Physaloptera (canine & feline stomach worm)
Spirocerca lupi (canine & feline esophageal worm)

19. Nematoda: Hookworms
So called because the larva and adult worms have cartilaginous hooks in their mouths that can hook onto intestinal tissue
Highly parasitic, the larva can hook onto paw pads or bare feet, burrow into the skin, migrate through lymph or blood vessels to the lungs or abdominal viscera
Condition is known as Cutaneous Larval migrans with tracks under the skin—highly zoonotic

20. Nematoda: Hookworms
Common veterinary hookworm:
Ancylostoma caninum

21. Nematoda: Whipworms
So named because of the shape of the adult worm; much like a bull whip
Complex life cycle, often transmitted fecal-oral or by eating undercooked meat
Adult worm infests lower intestine and colon
Common veterinary species:
Genus Trichuris

22. Nematoda: Threadworms
So named because of very thin and small size of adult worm.
Commonly called “Strongyloids”
Complex life cycle with final stop in intestines of host animal—many of the smallest strongyles are not parasitic and live in commensalism with the host, particularly in horses and cattle
Larger strongyles are always parasitic
Common veterinary Genus: Strongyloides

23. Nematoda: Heartworm
Blood parasites that reside in the blood vessels when young;
Heartworm is commonly vectored by mosquitos
Eggs are not visible in the blood stream, taking 6 months to develop into larva where it will finally be diagnosed

24. Nematoda: Heartworm
Adults reside in the heart and can cause valvular damage and muscle disease—often fatal once clinically diagnosed
Heartworm is a disease of the dog AND cat
Veterinary genus & species: Dirofilaria immitis

25. Kingdom Animalia: Phyla exhibiting pseudo body cavity with some enclosure
Phylum Nemertea, Bryozoa & Phoronoid are sea worms—Not important to our study
Phylum Brachiopoda is an important group because of its members have a hinged shell (top and bottom).
Brachiopods also have pseudo mouths with a more defined body cavity. EX: Oysters

26. Phlyum Mollusca Mollusks: including clams, snails and octopi.
Body cavity is completely enclosed by a lining and animals have a circulatory system that is more defined.
Pseudo brain is present—but no spinal cord
Most are marine, but some are terrestrial
Sea forms have gills for gas exchange like fish
Land forms have pseudo lungs and usually have a muscular foot of some type for locomotion like snails

27. Phlyum Mollusca Classes: Gastropoda (snails and slugs)
Bivalvia (clams & scallops)
Cephalopoda (squids and octopi)
FYI: Squids (Order Decalopoda) have 8 arms and 2 tentacles
Octopi (Order Octopoda)
have 8 arms and no tentacles

28. Phylum Annelida AKA segmented worms
This is the start of the animal phyla with a psuedo digestive tract—meaning some sort of mouth, intestines and excretory device.
Group includes earthworms (non-parasitic)
and Leeches (parasitic)

29. Phylum Arthropoda: The largest of all Animalia Phyla
Arthropod means jointed leg—these are the first animals with extremities
Still invertebrates—no backbone—skeleton is on the outside (exoskeleton) and composed of proteins
Is molted or shed; known as Ecdysis

30. Phylum Arthropoda:
First animals with obvious and separate head—have all features of lower phyla (body cavities, pseudo intestinal tract, some pseudo circulatory system, but not a blood with cells like mammals)
Aquatic classes have gills; land classes have a tracheal like tube leading to air sacs
Many classes with a variety of species;
3 important:
Crustacea (lobsters, crabs, shrimps)
Insecta (2/3 of all animals are insects)
Arachnida (spiders, scorpions, ticks, mites)

31. Phylum Arthropoda: Class Insecta
3 body parts (head, thorax, abdomen)
All have 6 legs; some have antenna
Some have wings extending from thorax
All have definite mouth parts with either biting parts, proboscis tube (sucking parts) or sponging features (blotting & sucking)

32. Phylum Arthropoda: Class Insecta
Most insects are sexual with internal fertilization
More developed ganglian system with central nerve branching off throughout anatomy (but, no actual spinal cord )
Young will go through several stages:
egg, nymph, larva, adult
(some with caterpillar & cocoon stage)

33. Important Insect Orders (on reverse of animal handout)
Hemiptera (true bugs, beetles) not parasitic, but can cause rashes, itching from extensive biting EX: bed bugs
Phthiraptera (lice—louse is singular)
Parasitic: either living off blood of host or chewing on dermis, dead tissues, hairs causing rash & skin disease
Suborders:

34. Important Insect Orders (on reverse of animal handout)
Mallophagia (biting lice) infest all domestic species—not normally dogs
Anoplura (sucking lice) infest all domestic species except birds and cats
Infestation is clinically termed Pediculosis
EX: Pedicinus capitus is the common human head lice

35. Insect Orders: Diptera
Diptera are the flies, gnats, and mosquitos
All winged and mostly parasitic
Mosquitos, gnats, and some flies have piercing & sucking devices for feeding off host’s blood
Some flies have large hinged mouth joints for biting;
Some flies have sponging parts for absorbing body fluids

36. Insect Orders: Diptera
Many members are vectors for a multitude of diseases (both human and veterinary):
Flies can transmit Staph & Strep infections; bacteria like that which causes pinkeye and other diseases
Mosquitos can transmit human and veterinary diseases like: Malaria, Diptheria, Yellow Fever, Elephantitis, West Nile Virus, Heartworm, Avian Flu

37. Insect order Siphonaptera
Commonly known as Fleas
All are parasitic and require time spent on host to feed
All are wingless, but with powerful hind legs enabling incredible jumping distances
Go through egg, nymph, larva & adult stages—adults are prolific and voracious feeders—flea infestation can make a small animal anemic

38. Insect order Siphonaptera
Vectors for many diseases—particularly tapeworm larva
Can also cause severe allergies due to rash and passing of “flea dust” flea feces which are pruritic to animals
Common vet species:
Ctenocephalides felis and Ctenocephalides canis

39. Other important Insect Orders
Lepidoptera (butterflies and moths) one of few insect orders with an egg, nymph, caterpillar, cocoon, adult
Hymenoptera (ants, bees & wasps) not parasitic, but certainly capable of inflicting major damage to small animals

41. Phylum Arthropoda: Class Arachnida
2 body parts (head, abdomen)
All have 8 legs; some will have 6 in larval stage & grow 2 more into adulthood
None have wings
All have definite mouth parts with either biting parts or the ability to inject poison

42. Class Arachnida Most arachnids are sexual with internal fertilization
Somewhat developed ganglian system with central nerve branching off throughout anatomy (no true brain)
Young will go through several stages:
egg, nymph, adult

43. Arachnid Orders
Scorpiones: ancient order—has had little development over several centuries—very effective assassin; have six walking legs with large pinchers (modified legs)
Araneae: True spiders—many species—some are highly poisonous and can kill small animals
EX: Brown Recluse or Black Widow (photos in Core First Aid Text)
Opilones: Daddy-Long-Legs is quite toxic, but unable to penetrate and inject large amounts of poison, rarely bite

45. Order Acarina: (arachnid order with veterinary importance)
Mites and Ticks
All terrestrial
Fused head and abdomen
Almost all are parasitic
Mites are much smaller than ticks and usually require microscope
Ticks are vectors of many diseases

46. Mites of Veterinary importance
Demodex follicurum- Cigar shaped mite which burrows under skin, living in hair follicles, feeding off skin & fluids, can only retrieve with skin scrape
Sarcoptes scabei- Tiny mite which burrows under skin causing nodules, rash and mange—highly contagious
Genus Psoroptes or Otodectes non-burrowing mite living on surface eating dead skin cells such as ear mite in rabbits

47. Ticks of veterinary importance
Argasid sub-order- ticks with soft shells
Vet EX: Genus Otobius
Ixodid sub-order- ticks with hard, ornate shell, larger & often decorative
Rhipicephalus sanguineus (brown dog tick)
vector for what canine disease?
Babesia canis—a blood protozoan

48. Ticks of veterinary importance
Genus Dermacentor (Deer or Wood tick)
vector for what zoonotic disease?
Rocky Mountain Spotted Fever, West Nile Virus
Genus Ixodes (black legged tick)
Lyme Disease

49. Phylum Echinodermata
Not important for our study, but important phylum representing the next step of complexity of animals
Complete digestive tract with mouth, digestive system, excretory device
EX: Sea Stars, Urchins
This is the last of the animal phyla for creatures without spinal cords