Bloody diarrhoea in the first few days of life is typical of necrotic enteritis. The diagnosis can be done by necropsy or with faecal samples. After confirmation by bacteriological culture, the toxins can be determined using PCR.

At necropsy, gross lesions include bloody intestinal contents and gas production. Histopathological lesions of necrosis of the intestinal lining (mucosa), destruction of the endothelial cells, and detachment of the basement membrane can be observed in some cases. In cases of chronic NE the intestinal mucosa is covered with thick, necrotic membranes, and this gives the intestines an appearance of band-like stripes.

The following diseases have to be considered for differential diagnosis:

• Colibacillosis
• Neonatal E. coli septicaemia
• Strongyloidosis
• Transmissible Gastro Enteritis (TGE)