Cytomegaloviruses

Salivary gland oncocytes in African hedgehogs (Atelerix albiventris) mimicking cytomegalic inclusion disease

The salivary glands from three African hedgehogs contained multiple foci of cytomegalic cells, which occasionally had a mild to moderate infiltrate of lymphocytes at the periphery. The cytomegalic cells were 35 to 40 microns in diameter with abundant acidophilic granular to hyalin cytoplasm. The nuclei were enlarged with clumped marginalized chromatin and a large, (6 to 8 microns in diameter) central, brightly eosinophilic nucleolus that had the appearance of an inclusion body by light microscopy. Histochemically most of the cytomegalic cells contained cytoplasmic metachromatic granules with Feyrter's thionine inclusion stain. Scattered cells at the periphery of the cytomegalic foci contained periodic acid-Schiff-positive cytoplasmic granules. Ultrastructurally the cytomegalic cells contained numerous tightly-packed, often bizarre, enlarged mitochondria that completely filled the cytoplasm. The nucleus consisted of a dense central core of chromatin associated with the nucleolus and the remaining chromatin was clumped and marginalized. Nuclear and cytoplasmic virions consistent with cytomegalovirus were not present. Histochemical stains of the nucleus for heavy metals were negative. The ultrastructural and histochemical findings of the cytomegalic cells were consistent with oncocytes. Previous reports in the literature of similar cells in the salivary glands of insectivores appear to have been erroneously described as cytomegalovirus infections.

Evaluation of murine cytomegalovirus antibody detection by serological techniques

Naturally acquired murine cytomegalovirus (MCMV) infection in laboratory strains of mice induces antibody levels which are generally undetectable by standard techniques; therefore, MCMV has not been included routinely in mouse viral antibody screening programs. The relative sensitivity of three assay systems, the nuclear anticomplement immunofluorescence (NACIF), the enzyme-linked immunosorbent assay (ELISA), and the complement fixation (CF) test, was evaluated for the detection of MCMV antibodies. Sera were harvested from CD1 male mice (33 days old) infected intraperitoneally with salivary gland-passaged MCMV (Smith strain). The sera were assayed separately at weeks 1 through 8, and at week 11, 16, and 25 post-inoculation; a total of 167 mice in 11 groups were tested. The animals tested at 1 week post-inoculation had low levels of antibodies to MCMV as measured by the NACIF test (1:10), whereas only 25% were positive by ELISA, and none was positive by CF until 5 weeks post-inoculation. A higher titer of MCMV antibodies was measured by CF (1:640) than by NACIF (1:40) at 6 months post-inoculation; yet, a titer of 1:3,200 was detected by ELISA from the same serum. The ELISA technique was more sensitive for detecting persistent infection with MCMV, and NACIF was more useful for detecting acute MCMV infection. Since MCMV can have significant long-term effects on the immune system, it is recommended that testing for antibodies to MCMV be included in mouse viral antibody screening protocols.

Epidemiology of cytomegalovirus infection in end stage renal disease

Since primary cytomegalovirus (CMV) infection is a cause of morbidity among renal transplant recipients, we undertook a prospective study of our maintenance hemodialysis patients and personnel to determine whether these sources posed a risk for transmission of CMV. Our study of 85 patients and 49 personnel showed that CMV was detected in eight nontransplanted, older dialysis patients and 13 patients who had lost their allograft. In spite of the presence of CMV on the unit, no patient or staff member developed primary infection from interpersonal transmission or from transfused frozen red blood cells. All primary infections in renal transplant patients could be accounted for by acquisition from the transplanted kidney, thus eliminating the dialysis unit or frozen blood as a risk to either patients or personnel.

Growth characteristics of cytomegalovirus in human fibroblasts with demonstration of protein synthesis early in viral replication

In high-multiplicity infection of human fibroblasts, human cytomegalovirus of WI-38 human diploid cells produced early cell rounding 6 to 24 h after inoculation. This early cell rounding was caused only by inoculation with infectious virions. Inhibitors of protein synthesis, but not DNA inhibitors, prevented this cytopathic effect. Apparently, a new protein is synthesized in infected fibroblasts from about 2 h postinoculation. Infectivity of cell-associated and supernatant infectious virus reached maximal levels at 5 to 7 and 10 days postinoculation, respectively. Synthesis of DNA, infectious virus, complement-fixing antigen, and precipitin antigen all began between 24 and 48 h, with the bulk of synthesis occurring 48 to 96 h postinoculation.