The internal parasites that affect small ruminants

Genus and species
Common name
Site
Life cycle
Conditions
Clinical signs
Significance
Haemonchus contortis
Barberpole worm
Wire worm
Abomasum
Direct
18 to 21 days
warm, moist
summer rainfall
Blood loss (Anemia)
Edema ("Bottle Jaw")
Weakness
Wool breaks
Sudden death
Major problem in warm, moist climates
(Ostertagia)
Teladorsagia circumcincta
Medium or brown stomach worm
Abomasum
Direct
20 days
cool, moist
Production loss
Lack of appetite
Diarrhea
Weight loss
Decreased wool production
Usually secondary to Barber Pole worm in warm, moist climates
Trichostrongylus  
Bankrupt worm
Hair worm
Abomasum
Small intestine
Direct
< 21 days
warm, moist
Black scours
Reduced appetite
Production loss
Ocassional death
Usually secondary to Barber Pole worm in warm, moist climates
Strongyloides papillosus 
Common threadworm
Small intestine
Direct
7-9 days  
warm, moist
Weight loss
Diarrhea
Inflamation between toes
Minor
Coopera spp.
small intestinal worm
Small intestine
Direct
20 days
cool, wet
winter rainfall

Loss of appetite
Diarrhea
Weight loss
Decreased wool growth

Minor
Additive
Nematodirus spp.
threadneck worm
Small intestine
Direct
20 days
cool, wet
Usually sub-clincial
Diarrhea, loss of appetite, weight loss
Usually secondary to Barber Pole worm in warm, moist climates
Dictyocaulus filaria
Muellerius capillaris
lungworm
hair lungworm
Trachea and bronchi
Direct
Indirect
(snails, slugs)
5 weeks
cool, wet
Usually no signs of infection. Coughing, fluid in lungs if disease is severe.
Pneumonia
Minor
Moniezia spp.
tapeworm
Small intestine
Indirect
(pasture mites)
6 weeks
 wet
Heavy infestations may result in unthriftiness and GI disturbances Mostly non-pathogenic
Eimeria spp.
coccidia
Small intestine
Direct
< 21 days
cool, wet condtions
Overcrowding
Liquid diarrhea
Off feed, depression
Death
Major
Trichuris ovis
whipworm
Caecum
Direct
6-12 weeks
Dry 
Diarrhea Of little consequence
Additive
Bunostomum phlebotomum
hookworm
Small intestine
Direct
1-2 months
 warm, most
Unthriftiness
Diarrhea
Blood loss
Anemia
Sore feet
Minor
Oesophagostomum  
nodule worm
Large intestine
Direct
5 weeks  
cool, wet
winter rainfall
Damage lining of small intestines Minor 
Paralaphostrongylus tenius

meningeal worm
deer worm
brain worm

central nervous system
Indirect (snails, slugs)
82-91 days
cool, wet
Hindquarter weakness
Ataxia
Paralysis
Blindness
Varies
Fasciola hepatica
liver fluke
Liver
Indirect
(snails, slugs)
 8-12 weeks
wet areas
production losses
Death
Organ condemnation
Varies

Created or last updated 17-Jul-2010 by Susan Schoenian.

©Copyright 2005-2010. Maryland Small Ruminant Page