Antiparasitic Drugs

Question 1

Ivermectin can be used to treat all stages of heartworm disease except?

Answer 1

Third stage larvae (L3)

Question 2

Which of the following drugs has a well established efficacy against developmental stages of heartworm and is often used as a prophylactic agent against infection by Dirofilaria immitis?

A. Selamectin (a macrocyclic lactone)
B. Fenbendazole (a benzimidazole)
C. Dichlorvos (an organophosphate)
D. Praziquantel

Answer 2

A. Selamectin (revolution)

Question 3

Which of the following drugs is the only clinically efficacious agent against adult heartworms in dogs and is administered by deep intramuscular injections?

A. Diethylcarbamazine
B. Piperazine salts
C. Melarsomine
D. Triclabendazole (a substituted benzimidazole)

Answer 3

C. Melarsomine (Immiticide)

Question 4

The following is a prototype drug for benzimidazoles; attacks beta-tubulin in parasite cells; has some antifungal activity and may be used in some ear medications.

A. Thiabendazole
B. Pyrantel
C. Emodepside
D. Levamisole

Answer 4

A. Thiabendazole

Question 5

Following fecal egg count and analysis on a sheep farm, you identify larvae and eggs of Haemochus species that has developed resistance to benzimidazoles and nicotinic imidathiazoles.

Which of the following drugs would you recommend to treat the resistant parasites?

A. Levamisol
B. Fenbendazole
C. Ivermection
D. Praziquantel

Answer 5

C. Ivermectin