Parasitology slide set 1

Question 1

An animal or plant which lives in or upon another organism and draws its nutrients directly from it; definition might also include- exhibits some degree of adaptive structural modification, causes harm to host

Answer 1

parasite

Question 2

Endoparasite

Answer 2

internal

Question 3

Ectoparasite

Answer 3

external

Question 4

Helminth

Answer 4

Worm

Question 5

Parasitology includes

Answer 5

protozoa, nematodes, flatworms, arthropods

Question 6

Helminths and arthropods are:

Answer 6

• complex multicellular organisms
• share many neurotransmitter and metabolic processes with vertebrate host, challenge is to affect parasite and not host
• drug’s effect usually determined by counting reduction in parasite numbers

Question 7

Protozoa are

Answer 7

• single celled organisms
• drug’s effect often measured by ability to reduce clinical signs
• some antibacterial drugs also used for protozoa

Question 8

-cide

Answer 8

kill; e.g. parasiticide, insecticide, nematocide

Question 9

Anthelminitic

Answer 9

drug used for treatment and control of worms

Question 10

Dose

Answer 10

the quantity to be administered at one time

Question 11

Dosage

Answer 11

the determination and regulation of the size, frequency, and number of doeses

Question 12

Half life

Answer 12

time required for one half of an administered dose to be cleared from the blood

Question 13

Mode of Action

Answer 13

how the drug works to kill an organism

Question 14

Spectrum of action

Answer 14

organisms affected (broad spectrum vs. narrow spectrum)

Question 15

Efficacy

Answer 15

how effective the drug is against an organism (usually measured in % reduction for multicellular parasites)

Question 16

Residual activity

Answer 16

length of time drug maintains efficacy after administration

Question 17

Safety (therapeutic) margin (index)

Answer 17

max tolerated dose/effective (usually the marketed) dose

Question 18

the higher the safety margin, the…

Answer 18

less likely for toxicity from drug

Question 19

Withdrawal time

Answer 19

amount of time after drug administration that potential food products must be held to avoid drug resides entering human food

Question 20

Subtherapeutic

Answer 20

does not have desired effect

Question 21

Dose limiting parasite

Answer 21

when a product is marketed for more than one parasite, the dose limiting parasite determines the dose required for treatment; usually is the highest concentration

Question 22

Treat or remove

Answer 22

90% reduction, minimum

Question 23

Repel

Answer 23

EPA; fewer organisms after short period

Question 24

Prevent

Answer 24

FDA- don’t get “mature” infection

EPA- ???- possibly means don’t get powerful infestation

Question 25

Control

Answer 25

FDA- couldn’t quite meet the standard for treatment (don’t use this on new products)
EPA- when already on board, the pesticide keeps numbers low

Question 26

Prescription only

Answer 26

from veterinarian or prescribed by veterinarian

Question 27

Ethical channel sales

Answer 27

doesn’t require a prescription, but drug company chooses to market through veterinarians

Question 28

Over the counter

Answer 28

freely available to public; most large animal parasiticides, many products for insects, ticks, and mites

Question 29

Treatment objective in small animals

Answer 29

• goal is eradication from animal
• many products from vet
• cost less important

Question 30

Treatment objectives in food animals

Answer 30

• goal is managing parasites, prevention of economic loss
• product usually not from vet
• cost very important

Question 31

Treatment objectives in horses

Answer 31

aspects of small animals and food animals, depends on owner

Question 32

Resistance

Answer 32

heritable characteristic
results from random mutation always present in population
use of a drug acts as a selection factor for resistant alleles and increases their frequency in the population

Question 33

Ways an organism could be resistant (a few examples)

Answer 33

change in drug uptake
change in drug receptor
change in drug metabolism by parasite

Question 34

refugia

Answer 34

pool of parasites not exposed to the drug

Question 35

What factors influence the rate of development of resistance?

Answer 35

frequency of treatment, efficacy, refugia, half life, genetics