Riemerella anatipestifer

R. anatipestifer is a Gram-negative bacteria known to cause septicaemia and death in young waterfowl worldwide. Clinical signs are most commonly seen in birds between the ages of 1–8 weeks old. High mortality up to 75% occurs in ducklings and goslings. In most cases, death occurs within 12-24h of the onset of clinical signs.

Systemic infection is common. However, infection may also become localised in joints and skin in chronic cases. In addition, localised infection of the oviduct of young layers can lead to permanent damage to the developing reproductive tract. This will prevent the proper formation or passage of eggs and result in the birds becoming "blind layers" when they grow up.

Disease is then multisystemic and can comprise of greenish diarrhoea, pyrexia, anorexia, growth retardation, nasal discharge, coughing, restlessness, polydipsia, ataxia, hypermetria, weakness, tremors and limb swelling. Nervous signs develop when the organism crosses the blood:brain barrier. Conjunctivitis, chemosis, scleral inflammation and ocular discharge sometimes also occur. In late disease, young birds may suffer from characteristic convulsions.

A multivalent vaccine is available in live and inactivated forms. The live form is administered as an aerosol spray at one day of age and the inactivated as two injections at 2 and 3 weeks of age.