Endoparasitism

Question 1

What are the groups of anthelmintics for horses?

Answer 1

• Benzimidazoles
• macrocyclic lactones
  
  • ivermectin
  • moxidectin
• pyrantel salts

Question 2

What are the pros/cons of Fecal egg counts?

Answer 2

• Provide information regarding patent infections
• will NOT provide consistent results for tapeworms/pinworms
  
  • qualitative is morse sensitive
• Quantitative fecal egg counts provide information regarding environmental contamination
  
  • relationship between worm burden and egg count is poor

Question 3

How is FECR calculated? what is the goal?

Answer 3

• (Mean_pretreatment - Mean_post) / Mean_pre x 100
• >90-95% is acceptable efficacy

Question 4

What is the lifecycle of ascarids?

Answer 4

• Ingestion of larvated egg in environment
• Hatch in small intestine → migrate through liver nd lung
• Larvae coughed up and swallowed
• mature in the small intestine

Question 5

Who is affected by ascarid infections?

Answer 5

• Most pathogenic parasites of horses <1yr
• Most horses develop acquired immunity
  
  • rare in horses > 2yr

Question 6

What are the clinical signs of an ascarid infection?

Answer 6

• Poor growth
• ill-thrift
• ascarid impactions
  
  • colic
  • nasogastric reflux
  • fever
  • distended small intestines

Question 7

What is the Prepatent period for ascarids

Answer 7

75 -80 days

Question 8

What anthelmintics are ascarids resistant to?

Answer 8

• Ivermectin & moxidectin - widespread
• Pyrantel - some areas

Question 9

What anthelmintic is recommended for roundworms?

Answer 9

• Benzimidazoles (Fenbendazole)
  
  • must use higher dose 10 mg/kg
  • less effective on immature parasites

Question 10

What are the deworming recommendations for ascarids in Foals?

Answer 10

• Stop deworming at birth
• Deworm when parasites are approaching maturity
  
  • PPP 10-12 wks → 60-70 days of age
• Fenbendazole 10 mg/kg
• Deworm every 60 days

Question 11

What is the life cycle of strongyles?

Answer 11

• Pass in the feces and hatch in the appropriate conditions
  
  • 45-85F
• Larvae mature into the infective L3 stage
  
  • die in hot weather >90F
  • survive freezing
• Once ingested, invade the lining of the cecum and large colon
  
  • may remain for a few weeks or as long as 2.5yrs
• Adult strongyles develop in the lumen of the large intestine

Question 12

What are the clinical signs of a small Strongyle infection?

Answer 12

• asymptomatic
• subclinical
• Acute diarrhea and protein loss