Herpes simplex virus type 1 and 2 in the adrenal glands: replication and histopathology

The adrenal glands were shown to be the most severely infected organs in the early phase of HSV-1 infections (up to 10 days p.i.) after i.p. infections in mice. Virus could be isolated from the adrenal glands as early as one hour after infection with pathogenic and apathogenic strains. Infection of the adrenal glands is a result of viremia. The content of HSV-1 (5 strains) was much higher in the adrenals than in spleen and liver. It peaked at 3-4 days p.i. compared to 1-2 days in spleen and liver. Only strain 17 syn+ produced low tissue titres in the adrenal glands. Morphologic alterations by HSV-1 infections commenced with distinct foci 2 days after infection in the zona fasciculata, detected immunohistochemically by HSV-specific peroxidase-staining. Necrotic cells could be observed. The foci became confluent until day 4 and remained in this status up to day 7 p.i. During infection immunocompetent cells (macrophages, granulocytes, many T-helper--but only few T-cytotoxic/suppressor lymphocytes) could be observed. On day 10 p.i. the viral antigen had been completely eliminated. In contrast, intraperitoneal infections with 5 strains of HSV-2 resulted in infection of the adrenal glands only to a low degree. The titer of virus was low (exception: strain HG 52). This correlates well with the type of disease produced by either HSV-1 or 2. By comparing the replication of different strains of HSV-1 and 2, three types of "tropism" after i.p. infection of mice can be distinguished.