Five cases of apparent relapse of herpes encephalitis were investigated. All patients recovered after antiviral and corticosteroid therapy. Samples of CSF taken from the patients at intervals through the initial and subsequent encephalitic episode were examined. PCR amplification of a 351 bp sequence from the Herpesvirus simplex (HSV) thymidine kinase gene demonstrated the presence of HSV DNA in CSF taken during the initial encephalitic illness but not during the second encephalitic episode. Intrathecal synthesis of HSV antibody (HSV antibody index > 1.9) was observed in all cases following the first episode, and there appeared to be no significant increase in intrathecal antibody synthesis in the second episode. High levels of CSF myelin basic protein were found during the acute phases of both the initial and the subsequent encephalitic illnesses. These data suggest that at least in our series of five patients, relapse following HSE may not be due to active viral replication.

In this study we aimed to determine the incidence of herpes simplex virus (HSV) in the lungs of burns patients, and its association with the presence of adult respiratory distress syndrome (ARDS) and pneumonia. Haematoxylin and eosin (H&E), and immunohistochemical (IHC) staining for HSV was performed on lung tissue from 54 patients who had died following burn injury and from nine control cases. Polymerase chain reaction (PCR) for HSV deoxyribonucleic acid (DNA) was performed on a subset both of burns cases and controls. No viral inclusions were detected in H&E sections, but 50% of the burns cases were positive for HSV by IHC staining; no control cases were positive. Nuclear and cytoplasmic immunopositivity for HSV was seen in macrophages and epithelial lining cells. HSV was strongly associated with ARDS (p=0.007), but not with pneumonia (p=0.577). The relative risk of HSV infection was higher for cases with ARDS (2.21) than for those with pneumonia (1.26). PCR for HSV DNA was positive in three out of five burns cases, and in one out of five control cases. Immunohistochemical staining is more sensitive for the detection of herpes simplex virus than haematoxylin and eosin staining for detection of viral inclusions. Burns cases have a high incidence of pulmonary herpes simplex virus infection. Polymerase chain reaction results may not be fully representative due to problems of tissue necrosis postmortem. Pulmonary herpes simplex virus is strongly associated with adult respiratory distress syndrome and the two may be causally linked. Early detection and treatment of pulmonary herpes simplex virus in burns patients may reduce pulmonary complications and mortality.

Three corneoscleral discs (from two donors) underwent subtotal endothelial loss during routine ''long-term'' organ culture storage. Laboratory studies of these corneas revealed evidence of herpes simplex virus (HSV) infection. The fellow cornea from one of the donors had been issued for transplant to a patient with keratoconus. Deterioration of the graft was noted 5 days after surgery; the disc was removed at 2 months and was shown to be infected with HSV. In an experiment designed to simulate initial ''cleansing'' of donor globes, 0.1% polyvinylpyrolidone-iodine protected cells from infection with HSV. It was concluded that the detection of HSV in these corneas could not be explained by external contamination of the ocular surface. Furthermore, culture of conjunctival and pharangeal swabs taken from 47 consecutive donors confirmed that HSV is rarely isolated at or around the time of death. Five pairs of donor corneas destined for use in transplantation were selected at random and investigated for the presence of HSV. HSV DNA was detected by polymerase chain reaction (PCR) in tissue from two of the corneal donors. Sequential stepwise sectioning suggested that HSV DNA when present was distributed in discrete foci within the cornea. These observations suggest that HSV infection may be a cause of severe endothelial loss during corneal organ culture and possibly provide an explanation for some ''failures'' of corneal grafting.

A number of techniques for extraction of DNA prior to polymerase chain reaction (PCR) amplification of herpes simplex virus (HSV) DNA in cerebrospinal fluid (CSF) were compared to the use of "native" CSF in the PCR reaction. The results indicate that extraction of DNA (which allows efficient removal of inhibitors of Taq polymerase) is an essential pre-requisite of the PCR detection of CSF HSV DNA.