Introduction

Infection of chickens with the protozoan parasite Eimeria praecox is spread in exactly the same as that with E. mitis but is practically non-pathogenic.

Signs

• Normally asymptomatic but may cause reduced feed efficiency and reduced weight gain, and predispose to other intestinal conditions.

Post-mortem lesions

• Minimal, but usually excess liquid and mucus in the duodenal loop.
• Severe infection can cause dehydration through excessive fluid loss.
• The cells of the sides of the villi (not tips) are usually parasitised.

Diagnosis

Identification of characteristic slightly ovoid oocysts in the duodenum in the absence of E. acervulina lesions. It has a very short pre-patent period (c. 80 hours).

Treatment

Not usually treated but susceptible to the products used for other forms of intestinal coccidiosis.

Prevention

Normally controlled by anticoccidials in feed. Not usually included in vaccines.