Measles viremia is thought to peak at onset of rash and diminish rapidly over the subsequent 2-3 days. The length of viremia and the proportion of peripheral blood mononuclear cells (PBMC) infected during measles were investigated in 8 adults. Blood was obtained from 7 patients between days 2 and 4 of rash. Five patients had repeat specimens obtained on day 6 or 7, and 1 patient had samples taken on days 6 and 10. Limiting dilutions of PBMC were cultivated with cord blood PBMC and stimulated with phytohemagglutinin. Virus was identified by syncytia formation and confirmed by immunofluorescent staining. Virus was isolated from all 8 patients. Four of 6 patients were still viremic at day 6 or 7 of rash. Titers ranged from 3 to 5623 TCID50/10(5) PBMC. Adults with measles may have prolonged viremia, and a large proportion of PBMC may be infected.

By using a conventional tissue culture method as a standard, four shell vial centrifugation culture (SVC) formats were compared for herpes simplex virus (HSV) detection in 300 clinical samples. Both MRC-5 and primary rabbit kidney (PRK) çells were used in the conventional and SVC systems. In addition, both a direct monoclonal fluorescent antibody to HSV (MAb-FA; Syva Corporation, Palo Alto, Calif.) and an indirect HSV polyclonal antibody-horseradish peroxidase stain (poly-HRP; Difco Laboratories, Detroit, Mich.) were used to stain shell vials of both cell types. Conventional tubes were incubated for up to 7 days with daily examination for cytopathic effect, which was confirmed as HSV by staining with an MÀb-FA. Shell vials were inoculated, centrifuged, incubated for 16 to 24 h, and stained directly with MAb-FA or indirectly with a poly-HRP stain. Of the 300 specimens examined, 82 (27%) were HSV positive by conventional tissue culture. PRK cells detected 81 (99%) positive specimens, compared with 74 (90%) specimens detected with MRC-5 cells. Of the 82 positive specimens by conventional culture, the SVC formats detected 68 by MRC-5 and MAb-FA, 74 by MRC-5 and poly-HRP, 64 by PRK and MAb-FA, and 77 by PRK and poly-HRP. Therefore, PRK stained by an indirect method with poly-HRP was the most sensitive of the SVC formats tested, detecting 94% of the positive specimens.

The isolation and identification of herpes simplex virus types 1 and 2 from clinical specimens with a 48-h system was compared with a conventional tissue culture detection method.

No abstract

The Clearview Chlamydia assay (Wampole Laboratories, Cranbury, N.J.), the PACE 2 DNA probe assay (GenProbe, San Diego, Calif.), and culture were compared for their abilities to detect Chiamydia trachomatis from cervical specimens in a population with a low prevalence (3.9%o) of chlamydial infections. A consensus reference method was used. The consensus reference method defined a positive specimen as one with a positive culture result or positive by both of the two nonculture methods. Of the 940 specimens tested, 37 were positive; 36 were positive by culture, 28 were positive by the PACE 2 assay, and 27 were positive by the Clearview assay, giving sensitivities of 97.3, 75.5, and 72.91%, respectively, and specificities of 100, 97.1, and 98.9%o, respectively. There was a direct correlation between the number of inclusion-forming units detected by culture and the ability of the two nonculture methods to detect the positive specimens.