Recognition and quantitation of herpesvirus particles in human vesicular lesions

Reliability of the Herpes Simplex Virus Immunofluorescent test in Corneal Disease

Herpetic ocular disease never produces well-identifiable morphological aspects. It is expensive, complicated and slow to culture Herpes simplex virus. The validity of the fluorescent monoclonal antibodies test was investigated using corneal cells with or without a sure herpetic lesion. The tests, on 36 cases without sure herpetic lesions, were always negative, while of the 42 patients with a clinically ascertained herpetic lesion, 38 were positive (90.5%) and 4 negative (9.5%), two of these on account of inadeguate tissue preparations. Thus, this method can prove useful and reliable for diagnostic purposes.

PHYSICAL AND BIOLOGICAL OBSERVATIONS ON HERPESVIRUS

Smith, Kendall O. (Baylor University College of Medicine, Houston, Texas). Physical and biological observations on herpesvirus. J. Bacteriol. 86:999-1009. 1963.-The development of herpesvirus in human lung fibroblasts was studied by plaque assays and physical particle counts. Approximately 200 infectious units and 60,000 particles were produced by single cells during a single growth cycle. Production of physically recognizable particles preceded infectious virus particle production by about 5 to 6 hr, suggesting the occurrence of a maturation process during formation. Aggregation of particles in clusters and chains was observed in many cases. One of the mechanisms for this aggregation was the connection of particles by deoxyribonucleic acid strands. These strands appeared to connect some particles in a way that suggests a structural continuity between their cores.

MORPHOLOGY OF CYTOMEGALOVIRUS (SALIVARY GLAND VIRUS)

Smith, Kendall O. (Baylor University College of Medicine, Houston, Texas) and Lucy Rasmussen. Morphology of cytomegalovirus (salivary gland virus). J. Bacteriol. 85:1319-1325. 1963.-The size and fine structure of cytomegalovirus was compared with that of herpes virus. Cytomegalovirus stains as a DNA virus and is almost identical in size to herpes virus. Both viruses have enveloped forms and display protein membrane subunits which are almost identical in number, size, and arrangement. Cytomegalovirus closely resembles herpes virus produced early in its growth cycle (9 hr) in that most of the particles are coreless and somewhat ragged in appearance. The particle-infectivity ratio with cytomegalovirus is extremely high, approximating 10(7) to 10(8). Although the average yield per cell was approximately 10,000 particles, only about one infectious unit per 1,000 cells was obtained. The biological explanation for this inefficiency of infectious virus synthesis is presently unknown, but the physical explanation appears to be that the nucleic acid cores are not complete. Not one particle was found, among over 1,000 examined, which stained as if it had a complete core.

Improved detection of HSV by electron microscopy in clinical specimens using ultracentrifugation and colloidal gold immunoelectron microscopy: comparison with viral culture and cytodiagnosis

Three tests were compared to diagnose herpes virus infection: electron microscopy (EM), viral culture (VC) and cytodiagnosis (Tzanck smear). The study comprised 67 patients with skin or mucous membrane lesions suggestive of herpes simplex virus (HSV) infection. The sensitivity of EM increased 25% after virus concentration by ultracentrifugation. Herpes virus infection was confirmed in 55 of the 67 cases by EM or VC or both. EM detected 53 herpes virus-positive lesion samples of which 14 were not detected by VC; only two lesion samples that were herpes virus-positive in VC were not detected by EM. The sensitivities of EM, VC, and Tzanck smear for the group of 55 herpes virus-positive cases were 96%, 75% and 76%, respectively. The specificity of the Tzanck smear was 83% (prevalence 82%). Colloidal gold immuno-EM was used to rapidly type HSV-1, HSV-2 and varicella zoster virus (VZV) present in skin and mucous membrane lesions in less than 4 h. Immuno-EM was able to detect antiviral antibodies on viral envelopes and viral cores in lesion samples with negative VC. Antiviral antibodies do not interfere with typing of herpes viruses by immuno-EM. It is suggested that formation of viral immune complexes and inactivation of virus particles by antibodies may have caused a negative VC. Improved EM is discussed for its applicability to special cases that cannot rely on VC and cytodiagnosis or when rapid diagnosis is required.

Comparison of ELISA with virus isolation for the diagnosis of genital herpes

An enzyme linked immunosorbent assay (ELISA) system which detects and simultaneously types herpes simplex virus antigens in clinical specimens from patients with genital herpes has been compared with standard tissue culture isolation. Although more sensitive than a similar method previously described and also more sensitive than electron microscopy and immunofluorescence, ELISA did not detect all the viruses isolated in tissue culture. Costs were comparable. The speed of obtaining the result together with knowledge of the type causing infection are useful when antiviral chemotherapy is envisaged and when considering the likelihood of recurrences.

Pseudoreplica electron microscopy for the detection of rotavirus: comparison with high-speed centrifugation electron microscopy and ELISA

Three-hundred and sixty-three stool specimens from patients with diarrhoea were examined for rotaviruses to compare the sensitivity of the pseudoreplica technique (PSD-EM) to that of high-speed centrifugation EM (HSC-EM) in relation to a commercially available (Rotazyme, Abbott) enzyme-linked immunosorbent assay (ELISA). In ELISA-positive cases, both methods were of equal sensitivity. However, in borderline (+/-) and ELISA-negative specimens, PSD-EM detected 31 of 48 (64.6%) and 18 of 229 (8%) positive specimens respectively, compared to only 22 of 48 (45.8%) and one of 229 (0.4%) positives detected by HSC-EM. PSD-EM detected a significantly higher number of positives compared to HSC-EM (p less than 0.05). In view of its simplicity, sensitivity and the fact that a relatively large number of specimens could be processed compared to HSC-EM, we consider that PSD-EM is a much better procedure for routine screening and diagnosis of viral gastroenteritis than HSC-EM.