Chapter 13(parasites)

Question 1

trophozoite

Answer 1

protozoan parasite stage that actively feeds and multiples

Question 2

cyst

Answer 2

protozoan parasite stage with a protective membrane or thickened wall

Question 3

fresh wet mount preparations

Answer 3

the best way to locate and identify protozoan parasites

Question 4

velvet disease

Answer 4

in fish common protozoan infections, caused by Piscinoodinium, ectoparasite

Question 5

white spot

Answer 5

in fish, caused by Ichthyophthirius multifilis, ectoparasite

Question 6

pseudopods

Answer 6

are an extension of their body that help the amoeba to move and engulf prey

Question 7

entamoeba histolytica

Answer 7

Causes amoebic dysentery, ulcers and diarrhea, can spread other organs such as liver, where they form abscesses
infects rats, dogs, cats(rarely), NHP, and humans
Apes, New World primates, and humans are most severely affected

Question 8

flagellates that are the only genera that contain species known to be pathogenic to lab animals

Answer 8

hexamita(Spironucleus), trichomonas, and giardia

Question 9

trypanosoma brucei

Answer 9

found in NHP and can infect humans, causing a disease called sleeping sickness
trypanosomes, are found in peripheral blood and lymphatic fluid rather than the GI tract

Question 10

balantidium coli

Answer 10

cilia pathogenic parasite
can infect humans, apes, some monkeys, and swine
causes diarrhea
diagnosis is made by microscopic fecal examination

Question 11

apicomplexan organisms

Answer 11

intracellular parasites that form spores as a means of transmission from one host to another

Question 12

apicomplexan organisms examples:

Answer 12

coccida, crytosporidium muris, eimeria stiedae, and toxoplasma gondii

Question 13

crytosporium muris is found where in which animals

Answer 13

GI tract of rodents

Question 14

what are helminths

Answer 14

multicellular, worm-like animals which have differentiated tissues and organs

Question 15

what are the groups helminths are classified in

Answer 15

Trematodes (flukes)
Cestodes (flatworms)
Nematodes (roundworms)
Acanthocephalids (thorny-headed worms)
Hirudineans (leeches)

Question 16

what is the life cycle of a fluke

Answer 16

1. eggs hatch in water and mature in an AQUATIC SNAIL
2. larval fluke hatch from snail and encyst on aquatic plants where they are then eaten by animals or people
3. once ingested, the cysts hatch and burrow through the intestinal wall into the peritoneum and migrate toward the liver
4. in the liver, the larva hatch into mature flukes and begin producing more eggs

Question 17

how do you diagnosis flukes in an animal

Answer 17

microscopically by finding eggs in the urine or feces or by finding adults on necropsy or in tissue sections

Question 18

what kind of parasite is a tapeworm

Answer 18

cestodes

Question 19

where and how are tapeworms found in the body of hosts

Answer 19

in the intestinal tract
they attach to the intestinal walls with a ring of hooks called a SCOLEX

Question 20

what are

Question 21

the chain of segments of a tapeworm called

Answer 21

proglottids

Question 22

what is the common tapeworm species found in dogs and cats?

Answer 22

Dipylidium caninum

Question 23

what are hydatid cysts

Answer 23

fluid-like cyst containing larvae in the host’s liver and other organs, usually when the tapeworm infests an unnatural host

Question 24

what are nematodes called?

Answer 24

roundworms

Question 25

what are the classes of roundsworms

Answer 25

nonsegmented, cylindrical, and elongate worms

Question 26

what do YOU need to know about whipworms?

Answer 26

Trichuris spp. they have bodies with a whip(hence the name) can infect most lab species adults inhabit the cecum or colon large numbers can cause diarrhea swine parasite: TRICHINELLA SPIRALIS it does not lay eggs, it puts larvae in host intestines they pass through the bloodstream to the muscle and grow there to encyst and infect

Question 27

Need to know about Ascarids

Answer 27

most commonly seen helminths in lab animals 3 types of these: toxacara canis, toxcara cati, and toxascaris leonia Toxocara canis: canine roundworm infect by dogs eating them of by larvae crossing the placenta and infecting fetuses

Question 28

need to know about pinworms

Answer 28

found in cecum and colon of NHP, rodents, and horses fecal-oral without intermediate host SYPHACIA SPP. AND ASPICULARIS TETRAPTERA are common in mice and rats

Question 29

need to know about hookworms

Answer 29

roundworm teeth-like structures enter through skin or fecal-roal or through placenta or milk ANCYLOSTOMA CANINUM: in dogs and cats OESOPHAGOSTOMUM spp: in old world monkeys and zoonotic to humans STRONGLYIS (strongyles): horse , fecal oral

Question 30

need to know about filaria

Answer 30

elongated, slender delicate ROUNDWORM female produces microscopic larvae (MICROFILARIAE) not eggs mosquitos and other blood-sucking insects are vectors DIROFILARIA IMMITIS heartworm of dogs found in heart and pulmonary arteries

Question 31

need to know about Acanthocephalids

Answer 31

thorny-headed worms Acanthocephala require and intermediate host latch to intestinal mucosa MONILIFORMIS MONILIFORMIS: rats PROSETHENORCHIS ELEGANS: New world monkeys detected through fecal sedimentation

Question 32

need to know about Annelida

Answer 32

leeches of the class Hirudinea infest through the nose, mouth, and parynx or attaching to the skin Dinobdella ferox observed hanging from nasal passages of rhesus monkeys and give them nose bleeds large number of leeches can cause anemia, asphyxiation, and death can be removed with gentle traction with forceps