Anti Parasitics And Role In Parasite Control

Question 1

Why is veterinary parasite chemotherapy important

Answer 1

In absence of a vaccine it is the only treatment method

Question 2

What is environmental engineering

Answer 2

Attempt to reduce parasite eggs in enviornemnt - expensive

Question 3

What is vector control

Answer 3

Target mediate shot of some parasites

Question 4

What is biological control

Answer 4

Using insecticides

Question 5

What is the issue of using insecticides

Answer 5

Molecules can have toxic side effects on species of animals as well as parts of the environment

Question 6

What is the biological control of nematodes

Answer 6

Etamotde eating fungi - eats nematodes
Nematodes that eat other nematodess

Question 7

What do we use for chemotherapy

Answer 7

Chemicals are used for parasite chemotherapy - it is dangerous

Question 8

What are the principles of parasite chemotherapy?

Answer 8

Selectivity drug must affect parasite and not host - must kill parasite and not host
Chemotherapeutic index - higher than index the safer the drug, lower the index the more toxic of the drug

Question 9

What are the potential mechanisms of parasite drug selection

Answer 9

Uptake or secretion of drug
Detoxification of drug
Activation of drug
Importance of drug target
Biochemical target
Unique target

Question 10

What is the uptake or secretion of drug

Answer 10

Kill parasite in the intestine to keep host safe

Question 11

What is detoxification of drugs

Answer 11

Host can detoxify or metabolise drug but the parasite hasn’t got the ability to do this

Question 12

What is activation of drug

Answer 12

Some drugs are given in a form that needs to be activated to work such as host stomach activates the drug before it reaches the parasite

Question 13

What is the importance of drig target

Answer 13

So protein target is more important for parasite survival to host survival meansing that’s host can use a different biochemical target to kill parasite

Question 14

What is binding to drug target

Answer 14

Drug may bind better to a parasite protein than a host protein

Question 15

What are current problems with current anti-parasitic agents

Answer 15

Re-infection in endemic areas
Some drugs expensive
Few have serious side affects
Resistance
Nvironmental resisdue issue

Question 16

What is the ideal anti-parasitic

Answer 16

Efficient against all parasitic stages of a species
Broad spectrum against man species
Non=toxic to host and environment
Metabolised and excreted by host
Easily administered
Reasonable cost

Question 17

What is the mode of action of levamisole

Answer 17

Agonists or antagonist thatch to acetcholine receptors of nematodes
Agonists = nematode loses acitvity as it enhances receptor activity
Antagonist = nematode stops working completely

Question 18

What is the importance of understanding parasite resistance

Answer 18

Only a limited number of effective and safe antiparasitic agents commercially available
Development of new drugs slow and resistance can rise rapidly

Question 19

What is parasitic resistance

Answer 19

The genetically transmitted bias of sensitivity i parasite populations previously sensitive to same drug
Drugs are getting restart such as river fluke

Question 20

What are the pharmacological mechanisms of parasite drugs

Answer 20

Loss of drug uptake mechanisms
Loss or modification of target site - due to mutation?
Parasite ompensate for loss of target activity - parasite found new biochemical pathway
Improved parasite detoxification pathway

Question 21

Why is tublin a makjor Benzimidazole target

Answer 21

Blocks assembly of tublin into microtubules
Cascade of changes causing a loss of cell homeostasis
Microtubules required for cell division, cell movement, cell shape - cascade of changes will block the assembly - cell blocks up

Question 22

What is the mode of action of benzimadzole on microtubules

Answer 22

Causes local unfolding in the tublin stoppin the tublin to join up

Question 23

What is the pharmacological selectivity of benzimidazoles

Answer 23

Binds both host and nematode tubulin

Question 24

What are the 2 groups of BZs

Answer 24

More inhibitory to parasite tublin - good
Inhibit parasite and mammalian tubulin with apparen same affinity - bad group

Question 25

What is the nature of mebendazole selectivity

Answer 25

Revealed by radio-labelling techniques
Mebendazole nematode tublin complex - more stable- this is why it disrupts nematode tublin and not host tublin
Highlights complexities in drug activists

Question 26

Hy is there wide spread resistance to benzimidasoles in veterinary nematodes

Answer 26

Tubulin from resistant nematodes reduced affinity for BZs

Question 27

How has the resistance to benzimidazoles occured

Answer 27

Structure changes in nematode tubulin targets as mutations in restraint nematode tubulin
Modification in nematode phase 3 drug pumps in membranes

Question 28

What is the mechanisms of benzimidazoles restiance at tubulin target

Answer 28

Tublin is cloned and sequence from resistant/sensitive nematodes - looks for differences in air acid strucutre

Question 29

How does benzimidazoles bind to target

Answer 29

Tubulin are built from amino acids coming from parts of the protein - resistance can be scattered across this protein
One nematode can have one mutation while another can have a different mutation
This means that the drug must me multi-complex to deal with the mutations