One of the intestinal enzymes that are generally deficient in children following an attack of severe infectious enteritis is –

`Because Lactase activity in the mucosa is at best marginal, this enzyme is particularly likely to be depleted secondary to diffuse mucosal disease' - Nelson Causes of Acquired Lactase deficiency 1. Acute Infective enteritis Viral gastroenteritis    Bacterial gastroenteritis        2. Cystic fibrosis                                 3. Protein-energy malnutrition     4. Cow's milk protein intolerance   5. Prolonged use of drugs like Neomycin.