The severity of herpes simplex viral keratitis in mice does not reflect the severity of disease in humans.

Four herpes simplex type 1 virus (HSV) isolates were selected from patients with mild ocular disease and four from patients with severe ocular disease on the basis of the number of epithelial recurrences, presence or absence of stromal disease, visual acuity, and the need for corneal transplantation. The scarified right corneas of 20 BALB/c mice were inoculated with each low-passage HSV isolate (1.0 x 10(7) plaque-forming units/ml) and examined three times per week for 2 weeks for the presence and severity of epithelial and stromal disease. The eight individual virus isolates differed with respect to the incidence of dendritic disease (P less than 0.001), the severity of dendritic disease (P less than 0.001), the incidence of stromal disease (P = 0.002), and the severity of stromal disease (P = 0.001) they produced in the mouse. The severity of disease was compared for the two groups of viruses: (1) those that had caused mild disease in their human hosts and (2) those that had caused severe disease. There were no statistically significant differences in the severity or incidence (44 versus 43 animals, respectively) of dendritic disease or stromal disease (27 of 80 animals in each group) between the two groups. These data suggest that the naive BALB/c mouse model of acute HSV keratitis after topical ocular inoculation does not reflect clinically significant differences in the severity of human HSV keratitis that might be caused by variations in the virus genome.