Parasite refresher Flashcards
What type of parasite is Echinococcus?
Cestode (tapeworm)
Which species are affected by Echinococcus granulosus?
Dogs - definitive hosts
Ruminants - intermediate hosts
Which species are affected by Echinococcus multilocularis?
Rodents - intermediate hosts
Foxes, coyotes, cats - definitive hosts
Which species of Echinococcus is notifiable?
Echinococcus multilocularis
Which parasite causes hydatid cysts?
Echinococcus granulosus
Which parasite causes alveolar cysts?
Echinococcus multilocularis
How do dogs become infected with Echinococcus granulosus?
Ingestion of cysts in organs of ruminants
How do ruminants become infected with Echinococcus granulosus?
Ingestion of eggs in dog faeces
Which species can Fasciola hepatica affect?
- Broad host range:
- Livestock = typical definitive host
- Humans can be affected
- Reservoir wildlife hosts = deer, hares, rabbits
Which parasite’s life cycle involves a snail as an intermediate host?
Fasciola hepatica
How do ruminants become infected with Fasciola hepatica?
Ingestion of metacercariae on contaminated vegetation
How do humans become infected with Fasciola hepatica?
Ingestion of metacercariae on contaminated vegetation e.g. watercress
Where are adult flukes (Fasciola hepatica) located in the body?
Bile ducts in the liver
When is chronic fluke disease most commonly seen? What is it associated with?
- Disease can be seen in late winter → spring → early summer
- Associated with prolonged intake of low→moderate metacercariae from herbage
True/false: chronic fluke disease can be associated with progressive loss of BCS, severe anaemia and submandibular oedema.
True
Which species does Haemonchus contortus affect?
Sheep and other ruminants
What is the pre-patent period of Haemonchus contortus?
15-21 days in sheep
What are the clinical signs of Haemonchus contortus infection?
- Pale conjunctiva and oral membranes
- Loss of BCS/reduced weight gain
- Reduced wool thickness/quality
- Oedema/submandibular oedema (bottle jaw)
- Death when blood loss overtakes erythropoeisis
Where is Haemonchus contortus found in the body?
Abomasum
(Pre-adult worms live in abomasa glands)
Which species does Nematodirus battus affect?
- Sheep
- Occasionally calves
What is the pre patent period of Nematodirus battus?
2-3 weeks
Which animals are typically affected by N. battus?
- Lambs especially recently weaned
- Older animals seldom affected
What are the clinical signs of N. battus infection?
- Ability of small intestine to exchange fluids and nutrients is greatly reduced
- Rapid weight loss
- Watery diarrhoea
- Dehydration
- Sudden death
Describe how sheep become infected by N. battus
Overwintered eggs hatch and infective larvae are ingested by ruminants
How do you control N. battus?
- Rotational grazing: sheep (Y1), Catte (Y2), Conservation (Y3)
- Control can be achieved by prophylactic use of anthelmintics with ewes dose prior to lambing
How do weather conditions affect N. battus survival?
- Warm March encourages an early hatch
- Cool and wet April/May will increase larval survival on pasture
What is the pre patent period of Ostertagia ostertagi?
3 weeks
Where in the body are Ostertagia found?
Abomasum
What are clinical signs of Ostertagia ostertagi infection?
- Diarrhoea
- Protein-losing enteropathy
- Loss of appetite → rapid weight loss
- Submandibular oedema (bottle jaw)
Which drug will kill Ostertagia ostertagi including the hypobiotic larvae?
Ivermectin
How do cattle become infected with Ostertagia ostertagi?
Ingestion of larvae on grass
Which species does Ostertagia ostertagi infect?
Cattle
