Mary Lane Martin

Clinical Virology of Ebola Hemorrhagic Fever (EHF): Virus, Virus Antigen, and IgG and IgM Antibody Findings among EHF Patients in Kikwit, Democratic Republic of the Congo, 1995

Ebola hemorrhagic fever (EHF) patients treated at Kikwit General Hospital during the 1995 outbreak were tested for viral antigen, IgG and IgM antibody, and infectious virus. Viral antigen could be detected in virtually all patients during the acute phase of illness, while antibody was not always detectable before death. Virus was also isolated from patients during the course of their febrile illness, but attempts to quantify virus in Vero E6 cells by standard plaque assay were often unsuccessful. IgG and IgM antibody appeared at approximately the same time after disease onset (8-10 days), but IgM persisted for a much shorter period among the surviving convalescent patients. IgG antibody was detectable in surviving patients through about 2 years after onset, the latest time that samples were obtained. Detection of Ebola virus antigens or virus isolation appears to be the most reliable means of diagnosis for patients with suspected acute EHF, since patients with this often-fatal disease (80% mortality) may not develop detectable antibodies before death.

Ultrastructure of infantile gastroenteritis virus

Abstract The virus associated with acute gastroenteritis in young children (infantile gastroenteritis virus (IGV) was examined by negative contrast electron microscopy. The surface of the particle was found to be composed of 32 large morphological units or capsomeres. In the closed shell of the particle they were clustered into a coordinated pattern characteristic of a T = 3 morphology and at low magnification appeared ring shaped. However, at a high magnification they were seen to be angular. Each was composed of separate wedge shaped subunits. There were 180 of these units, each of which was a trimer making a total of 540 structural units on the surface of the particle. The wedge shape of these subunits and their trimer arrangement follows the structure postulated for a T = 9 icosadeltahedron. Thus, on the level of structural units the particle conforms to a T = 9, whereas in the clustering of these units into 32 capsomeres, it conforms to a T = 3 morphology similar to that described for viruses of the orbivirus group.

The ultrastructure of disrupted herpesvirus nucleocapsids

Abstract Nucleocapsids prepared by treating herpes simplex or varicella-zoster virions with Nonidet P-40 were found to be degraded by EDTA-trypsin. Initial action of the enzyme appeared to be to degrade the pentameric capsomeres located on the vertices of the icosahedron and thus cause the capsid to flatten and the capsomeres to align in a characteristic radial array. Examination of hexagonal clusterings of capsomeres showed that they were linked by strands approximately 2 nm wide which originated from edges of the hexagonal prisms. A tri-membered arrangement for these intercapsomeric linkages was proposed in which one strand linked adjacent capsomeres and the central capsomere of the cluster.

Ultrastructure of human immunodeficiency virus type 2.

The ultrastructure of human immunodeficiency virus type 2 (HIV-2) was determined by negative stain and thin section electron microscopy (EM). Some virus particles had surface projections about 10 nm in length which were evenly spaced. Nonidet P40-treated particles which were penetrated by stain revealed a distinctive off-centre cone-shaped core and, in addition, free-lying cores were also seen in detergent-treated preparations. The surface of the cores was composed of a layer of small subunits. The structure of HIV-2 determined by thin section EM was the same as that deduced by negative stain EM.

The fine structure of the capsid of reovirus type 3

Abstract The fine structure of the outer capsid of reovirus type 3 was studied by negative contrast electron microscopy and enhancement of image detail by rotational analysis. The capsid was found to be composed of large morphological units, or capsomeres, measuring 18 nm in diameter. Hexagonal units are composed of six separate wedgeshaped subunits which are in turn made up of three smaller subunits. The architecture of the capsid appears to be that of a T = 3 morphology with a probable 32 morphological units which themselves have the more complex symmetry of a T = 9 icosadeltahedron. A prominent feature of the architecture of the capsid was found to be a sharing of subunits, an apparently unique feature of viruses in the Reoviridae virus family.

Biochemical Characterization of Infantile Gastroenteritis Virus (IGV)

Enzymic and biophysical studies with purified infantile gastroenteritis virus (IGV) nucleic acid indicated that the virion contained a double-stranded RNA genome of approx. 14 x 10(6) daltons which could be separated by gel electrophoresis into eight bands of RNA which were comprised of 15 RNA species. Two major virus proteins, VP2 (mol. wt. = 135,000) and VP8 (mol. wt. = 40,000), which composed about 85% of the total virion protein, were detected in IGV particles by polyacrylamide gel electrophoresis. Eight additional minor proteins were also resolved.

Further Observations on the Ultrastructure of Human Rotavirus

The inner capsid layer of human rotavirus was found to preferentially break up into large ring-like morphological units. The outer capsid was found to be composed of capsomeres covered by a thin protein or glycoprotein covering. These capsomeres appeared to be broad headed and short stemmed, similar to the type of pin used to mark locations on a map (pushpin).

Incidence of herpesvirus antibody among leukemic and nasopharyngeal carcinoma patients.

Summary This report presents data which show complement fixation or fluorescent antibody titers to the herpes virus group in sera from patients with leukemia, patients with nasopharyngeal carcinoma, and healthy controls. Higher titers against EBV, herpes simplex type 1, and varicella were found in the sera from nasopharyngeal carcinoma patients.

Biophysical properties of a non-cultivable 29-nm enteric virus.

A 29 nm non-cultivable virus (NCV) was detected in faecal extracts from children hospitalized for gastroenteritis. The NCV had a density of 1.35 g/ml in glycerol-potassium tartrate density gradients and was resistant to degradation by proteolytic enzymes, non-ionic detergents and pH extremes. The surface of these virus particles had knob-like projections which appeared to have a symmetrical arrangement. When heated to 56 degrees C, the virus was completely degraded to soluble components which could not be seen by electron microscopy.