Clinical Sign of Bovine Ostertagiosis

CLINICAL SIGNS

Bovine ostertagiosis is known to occur in two clinical forms. In temperate climates with cold winters the seasonal occurence of these is as follows:

The Type I disease is usually seen in calves grazed intensively during their first grazing season, as the result of larvae ingested 3-4 weeks previously; in the northern hemisphere this normally occurs from mid- July onwards.

The Type 11 disease occurs in yearlings. usually in late winter or spring following their first grazing season and results from the maturation of larvae ingested during the previous autumn and subsequently arrested in their developing at the early fourth larval stage.

The main clinical sign in both Type 1 and Type I1 disease is a profuse watery diarrhoea and in Type 1, where calves are at grass, this is usually persistent and has a characteristic bright green colour. In contrast, in the majority of animals with Type 11, the diarrhoea is often intermittent and anorexia and thirst are usually present. The coats of affected animals in both syndromes are dull and the hind quarters heavily soiled with faeces.

In type II ostertagiosis, hypoalbuminaemia is more marked and there is a moderate anaemia of unknown etiology. As a result of the hypoalbuminaemia submandibular oedema is often present. In both forms of the disease, the loss of body weight is considerable during the clinical phase and may reach 20% in 7-10 days. Carcass quality may also be affected since there is a reduction in total body solids relative to total body water.

In Type I disease, the morbidity is usually high, often exceeding 75%. but mortality is rare provided treatment is instituted within 2-3 days. In Type 11 the prevalence of clinical disease is comparatively low and often only a proportion of animals in the group are affected: mortality in such animals is very high unless early treatment with an anthelmintic effective against both arrested and developing larval stages is instituted.

Cinical Signs(In short):

·         Young calves are mostly affected

·         Profuse watery diarrhea (bright green colour)

·         Anorexia, Thirst, weight loss, emaciation

·         Dull, Depression

·         Hind quarter heavily soiled with feces due to diarrhea

·         Sub-mandibular oedema (due to hypoprotenemia)

·         Morbidity is 70% but mortality is rare

Pathogenesis of Ostertagiosis