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Cooperia species are nematodes of the small intestine of ruminants. Species in domestic animals are usually 5-9mm long and males have a prominent bursa in relation to their size. Cooperia curticei is easily recognized on microscopic examination by its coiled appearance that has been described as like a "watch spring", as shown in the accompanying image of a female.

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The most distinguishing morphological feature of the genus is the cephalic vesicle, found in all the species, giving the head end a slightly bulbous appearance when worms are examined under a dissecting microscope or under the low power of a compound microscope. In addition the anterior cuticle has transverse striations and these can be seen by clicking on the image or here.

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Male spicules are short and their shapes may be used to identify the different species. The image on the right shows the tail end of Cooperia oncophora with a prominent bursa typical of the genus and paired spicules whose shape is characteristic of the species..

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There are five important species in ruminants.

Nematode Species Host Species Predilection site Distribution
Cooperia curticei sheep and goats small intestine Worldwide. Common in sheep in Australia. More common in cool temperate areas
Cooperia oncophora cattle small intestine Worldwide. Commonest Cooperia species in Australia. More common in cool temperate areas of the world.
Cooperia pectinata cattle small intestine Worldwide. More common in southern states of the U.S. Found in Puerto Rico and Hawaii. More prevalent in warm temperate and subtropical areas.
Cooperia punctata cattle small intestine Worldwide. Important in Hawaii. More common in warm temperate and subtropical areas.
Cooperia surnabada cattle and sheep small intestine Worldwide but more common in cool temperate areas.

Life cycle

The life cycle is direct and similar to the other Trichostrongyles. Arrested development is an important feature of the life cycle.


Cooperia are generally considered to be mild pathogens. They contribute secondary effects to the primary pathogens Ostertagia and Haemonchus in parasitic gastroenteritis. However, Cooperia punctata, pectinata and suranabada are believed to be more pathogenic since they penetrate the mucosa during larval development causing changes similar to those of intestinal species of Trichostrongylus.


Patterns of transmission are different depending on the species. In temperate climates the patterns follow Ostertagia with winter hypobiosis at the L4 stage in the northern hemisphere. In subtropical areas the patterns of transmission follow those of Haemonchus with hypobiosis during the dry seasons.

Clinical signs

A variety of clinical signs have been attributed  to Cooperia species and these include diarrhea, weight loss, anorexia and poor weight gains.

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Cooperia infections are usually secondary contributors to parasitic gastroenteritis caused by the more important nematodes, Ostertagia and Haemonchus. Therefore, they are rarely diagnosed as monospecific infections. However, like most other trichostrongyles, females pass strongyle-type eggs that may be found in host feces. The image to the right shows strongyle-type eggs (including Cooperia) and a Nematodirus egg (A) in a fecal sample.

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Parásitos y enfermedades parasitarias de los animales domésticos
Dr. Colin Johnstone (autor principal)
Derechos de copia © Universidad de Pennsylvania