One of the intestinal enzymes that is generally deficient in children following an attack of severe infectious enteritis is:
Secondary lactose intolerence follows small bowel mucosal damage (celiac disease, infective diarrhea) and usually transient, improving with mucosal healing. Ref:Kligman, Behrman, Jenson, Stanton (2008), Chapter 335, "Disorders of Malabsorption", In the book, "Nelson's Textbook of Pediatrics", Volume 2, 18th Edition, New Delhi, Page 1598
Lactase
Trypsin
Lipase
Amylase