Page 162 - The Veterinary Laboratory and Field Manual 3rd Edition

Parasitology 131

Table 3.3 A guide to the significance of faecal egg count (EPG – eggs per gram)
in faecal samples collected from sheep and cattle.

Worm species degree of infestation – cattle degree of infestation – sheep
Light Moderate Heavy Light Moderate Heavy
Nematodes (round worms)
Mixed 200–700 > 700
Mixed without Haemonchus < 500 500 > 1000
sp.
Haemonchus sp. 200 200–500 > 500 100–2500 2500–8000 > 8000
Ostertagia (Teladorsagia) 50–200 200–2000 > 2000
circumcinta
Ostertagia ostertagi 150 > 500
Trichostrongylus axei 50 50–3000 > 300
Trichostrongylus spp. > 500 100–500 500–2000 > 2000
Nematodirus sp. 50–100 100–600 > 600
Strongyloides sp. > 10,000
Bunostomum sp. 20 20–100 > 100
Cooperia sp. 500 500–3000 > 3000
Cooperia punctata 50 200 > 200
Oesophagostomum radiatum 50–150 150–500 > 500
Oesophagostomum 100–1000 1000–2000 > 2000
columbianum
Chabertia ovina > 1000
Cestodes (tapeworms)*
Moniezia sp. >10.000 > 10,000
Trematodes**
Fasciola hepatica > 0 > 50 50–200 200–500 > 500
Notes: Information collated from a number of sources. Note that it is difficult to differentiate species of many of the strongyle
worms using egg examination. Faecal egg counts should be assessed in view of the clinical condition of the animals sampled.
The number of eggs produced by the parasite depends on the species and fecundity of the worm(s) and the degree to which the
host’s immunity interferes with the parasites’ ability to compete for resources.
*In most cases host-adapted adult ruminant cestodes are only pathogenic in very high numbers, however, the cyst form of
carnivore tapeworms may cause clinical disease in the ruminant intermediate host.
Trematodes (Flukes)
**Schistosoma sp. – demonstrate variable levels of pathogenicity, depends on species of fluke, host age and immune status.
Low levels (10–100) of some species are considered pathogenic in young stock. Need to assess significance in view of clinical
signs seen, usually recommend treatment.

5.0–40.00 cm long (Ascarids). Although most worm (Dictyocaulus sp.) and the kidney worm
adult nematodes reside in the gastrointestinal (Stephanurus sp.). Owing to the fact that some
system, some species have become specialized to animals will have mixed helminth infections,
live in other organ systems, for example, lung- the severity and nature of the clinical signs seen

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