Alyne K. Harrison

Bunyaviridae: morphologic and morphogenetic similarities of Bunyamwera serologic supergroup viruses and several other arthropod-borne viruses.

Thin section electron microscopic examination of several viruses of the Bunyamwera serologic supergroup of arbo viruses confirmed their precise similarities in morphology and morphogenesis and their differences from viruses of other groups. Several viruses that are serologically unrelated to the supergroup were indistinguishable from Bunyamwera virus when observed in the same way. A separate taxonomic group or ‘family’, ultimately to be based upon multiple common physicochemical virion properties, is proposed to encompass the more than 130 viruses listed; the name Bunyaviridae is proposed for this taxon.

Characterization of Nodamura virus, an arthropod transmissible picornavirus

Abstract Nodamura virus, an arthropod-transmissible virus which is resistant to ether and chloroform, was characterized by electron microscopic, physical, and additional immunological studies. Examination of thin sections of limb muscles of infected infant mice revealed extremely large numbers of virus particles (28 nm in diameter) dispersed and in crystalline array within sarcoplasm. Two kinds of viroplasmic inclusions and severe destruction of skeletal muscle cell architecture were associated with the presence of virus. Kupffer cells in the liver of these animals also contained large aggregates of virus particles. Negative contrast preparations contained virus particles 29 nm in diameter with cubic symmetry. The virus was morphologically indistinguishable from picornaviruses. The density of infectious virus was 1.34 g/ml; it was insensitive to pH 3.7, and its sensitivity to heat (50 °) was not stabilized by molar MgCl 2 . Since serum neutralization tests against 10 swine enteroviruses were negative, as were previously reported attempts at serological identification, Nodamura virus remains a picornavirus unrelated to any known virus, but with a demonstrated capacity for transmission by and multiplication in arthropods.

Colorado tick fever virus: An electron microscopic study

Abstract Colorado tick fever (CTF) virus was observed by ultrathin section and negative contrast electron microscopy. In sections of infected cultured cells and of mouse brain, virus particles (75 mμ in diameter) with electron dense cores were associated with intracytoplasmic granular matrices, arrays of intracytoplasmic filaments, and fine kinky threads. Occasionally, virus particles were enveloped by membranes of cytoplasmic organelles. Intranuclear filaments in dense arrays were frequently found in infected cells. In negative contrast preparations the virus was round, 80 mμ in diameter, with regularly spaced surface projections suggestive of cubic symmetry. Partial removal of surface components permitted the observation of an inner capsid 50 mμ in diameter. CTF virus was directly compared with reoviruses, which in several ultrastructural characteristics it resembles.

Studies on the poxvirus cotia

The poxvirus Cotia was studied by electron microscopy and by serological and biochemical analyses. Thin-sectioned preparations of infected Vero cells indicated that Cotia virus morphogenesis was similar to other mammalian poxviruses; unique filamentous structures and inclusion matrices were apparent in the cytoplasm. Complement fixation tests that included purified Cotia virions showed a reciprocal cross-reaction with rabbit myxoma virus and no cross-reaction with vaccinia virus. Serological results coupled with gradient polyacrylamide gel electropherograms of the structural proteins of purified Cotia, vaccinia, myxoma and fibroma viruses suggested that Cotia virus was similar to the latter two viruses. Agarose gel electropherograms of cleavage fragments of each of these virus DNAs digested with three separate restriction endonucleases showed that each of these viruses had a unique DNA gel profile.

Lyssavirus infection of muscle spindles and motor end plates in striated muscle of hamsters.

SummaryImmunofluorescent, light, and electron microscopy were used to document lyssavirus infection of muscle spindles and motor end plates. Virus particles were seen in the narrow intercellular space between sensory nerve endings and intrafusal muscle fibers; they were also observed budding from intracellular and plasma membranes of the latter. Involvement of motor nerves and motor end plates could only be demonstrated by electron microscopy. In nature, rabies virus invasion of the peripheral nervous system must involve centripetal spread across these junctions.

Viral pancreatitis: Ultrastructural pathological effects of coxsackievirus B3 infection in newborn mouse pancreas

Abstract An electron microscopic study of Coxsackievirus B3-infected newborn mice revealed pathological changes in both the endocrine and exocrine portions of the pancreas. Damage ranged from a focal degeneration in which small areas of individual cells were affected to a widespread necrosis and inflammation in which entire acini and islets were so changed that identification of individual cell types was difficult. Compound membrane-vesicle complexes typical of picornavirus infection and virus particles in various arrays were observed in the acinar cells and macrophages. Fibrosis of the islets and a thickening of the basal laminae of associated capillaries were noted also. Comparisons were made to the pancreatitis caused by this and other group B Coxsackieviruses in both human and experimental animals.

Ultrastructural pathology of coxsackie A4 virus infection of mouse striated muscle

Abstract Electron microscopic examination of Coxsackie A4 virus-infected hind limb muscles of suckling mice showed generalized myositis with almost total loss of normal muscle cell architecture. Degenerative changes included dilatation of sarcoplasmic reticulum with concurrent disruption of myofibrils, presenting the appearance of dense amorphous masses in some areas; large accumulations of membrane-bound vesicles; swelling, distortion, and mineralization of mitochondria; increase in lipid deposits; pyknosis of the nuclei; edema and inflammatory infiltration. Virus particles were present in a number of different configurations in muscle fibers: individual particles or small accumulations within vacuoles, two-dimensional linear arrays between membranes, and three-dimensional crystalline arrays, usually in close apposition to sarcoplasmic reticulum or sarcolemma.

Antigenic Relationship between Human Coronavirus Strain DC 43 and Hemagglutinating Encephalomyelitis Virus Strain 67N of Swine: Antibody Responses in Human and Animal Sera

Abstract Hemagglutinating encephalomyelitis virus of swine (HEV) was adapted to growth in suckling mouse brain. Electron micrographs of HEV-infected suckling mouse brain, prepared by negative staining and thin-section techniques, exhibited typical morphological characteristics shared with other members of the Coronaviridae. The adaptation of HEV to suckling mouse brain facilitated serologic testing by the use of common host reagents and compatible animal systems. With hemagglutination inhibition, complement-fixation, and neutralization tests, an antigenic relationship was demonstrated between human coronavirus OC 43 and HEV in specific immune and hyperimmune animal sera. Children and adults with seroconversion to OC 43 antigen had diagnostic rises in titer of antibody to HEV antigens. Individuals with seroconversion to human coronaviruses 229E and B814 demonstrated antibody to HEV but not diagnostic rises in titer. Swine with titers of antibody to HEV had lower or no detectable titers of antibody to coronavirus OC 43. Although the prevalence and geometric mean titer of antibody to DC 43 were higher than the titer of antibody to HEV in every group of normal humans tested, significant differences in antibody response to coronavirus DC 43 and HEV were seen between populations that did or did not have possible contact with swine. The evidence suggested that antibody to HEV in humans probably represented a heterologous response to infection with coronavirus DC 43. However, a heterotypic response to unknown or uncharacterized strains of coronavirus cannot be excluded.

A bat rabies isolate with an unusually short incubation period.

Abstract Rabies viruses from two types of bats were inoculated intracerebrally into laboratory mice. The reactions of the mice differed markedly. Those inoculated with virus from a Mexican freetail bat, Tadarida brasiliensis mexicana , died a violent death after an incubation of 4 to 5 days. The pathology was marked, with much neuronal destruction noted. Those mice inoculated with virus from a vampire bat, Desmodus rotundus , died after incubation periods similar to those noted after inoculation of common “street” viruses, i.e., 7 days or more. The pathology corresponded to the limited amount usually seen after death from “street” virus.

Human T-Cell Leukemia Virus in Lymphocytes of Two Hemophiliacs with the Acquired Immunodeficiency Syndrome

Fresh and cultured peripheral blood cells from two patients with hemophilia A and the acquired immunodeficiency syndrome were examined for markers of infection with human T-cell leukemia virus (HTLV) type 1. Neither patient had antibody to membrane antigens of HTLV-infected cells at the time of culture. Electron microscopy of peripheral blood cells from Patient 1 and cultured cells from Patient 2 showed type C retrovirus-like particles. Examination of peripheral blood lymphocytes showed other smaller virus-like particles in circulating mononuclear cells from both patients. Indirect immunofluorescence of peripheral mononuclear cells from both patients and of cultured cells from Patient 2 showed staining with antibodies to purified HTLV and to HTLV core proteins p24 and p19.