Practical 3: helminths

Question 1

What is the faecal egg count reduction test used for?

Answer 1

To test for drug resistance in helminths

Question 2

At what % efficacy is resistance suspected?

Answer 2

95% and lower

Question 3

What does the egg hatch test test for?

Answer 3

Thiabendazole resistance

Question 4

How do benzimidazoles work?

Answer 4

Bind to tubulin to disrupt microtubule function

Question 5

How was the egg hatch test conducted?

Answer 5

Sheep faecal samples containing helminth eggs from two different farms were mixed with varying concentrations of thiabendazole and viewed under a microscope. The number of eggs and larvae in each concentration was counted and % hatch calculated.

Question 6

How is % hatch calculated?

Answer 6

(No. of larvae/ (no. of eggs + no. of larvae)) x100

Question 7

Based on the egg hatch test, which sheep were resistant to benzimidazole?

Answer 7

Sheep from farm A were resistant based on a >0.3micrograms/ml ED50

Question 8

resistance to what drug was the faecal egg count reduction test testing for?

Answer 8

Ivermectin