Herpetic keratitis in zinc-deficient rabbits.

In a study of 57 rabbits, we found that zinc played a vital role in the growth of the rabbit and in its immunocompetence. Both humoral and cellular immunity were depressed in the zinc-deficient rabbit. Not only did zinc-deficient animals fail to gain weight, differing in that respect from rabbits on a regular diet, but they also had a high death rate, in contrast with no deaths among normal rabbits. Herpes simplex virus keratitis, both epithelial and stromal, was more severe in the zinc-deficient rabbit but was not improved by local zinc replacement (zinc sulphate ointment, 0.05%); Zinc sulphate ointment (1%), which is four times stronger than commercially available zinc ophthalmic preparations, was severely toxic for the rabbit cornea.