Combinations of antiviral and anti-inflammatory preparations for the topical treatment of herpes simplex virus assessed using a murine zosteriform infection model

Recently we have reported a zosteriform murine infection model which employs the adoptive transfer of immune cells (ATI) to recipient infected mice to produce a disease that mimics human recurrent herpes simplex virus (HSV) disease. Mice were infected with HSV-1 by scarification at the lateroventral line of the neck; 2 days later, the mice received immune cells from HSV-1-infected syngeneic mice. Although virus was cleaved more quickly from the target tissues of virus replication in recipient mice, ATI resulted in a heightened inflammatory response and delayed healing. This model was used to test the effects of topical formulations containing foscarnet and/or the anti-inflammatory agent, hydrocortisone. Virus clearance and clinical signs, including ear thickness and zosteriform spread of lesions, were studied. Treatment with 3% foscarnet accelerated virus clearance but had little effect on clinical parameters. By contrast, 0.5% hydrocortisone increased the titre and extended the presence of infectious virus for at least 6 days, although the reduction in clinical signs was greater than that obtained with topical foscarnet. Foscarnet in combination with hydrocortisone produced a marked reduction in clinical signs while virus replication was reduced. These results are discussed in relation to the inflammation and discomfort experienced by patients and a possible role for anti-inflammatory formulations in the treatment of HSV reactivation episodes in man.