A new continuous cell line from the mosquito Psorophora confinnis (Diptera: Culicidae) and its susceptibility to infections with some arboviruses.
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A new cell line, PC-0199-BR, was established from embryonated eggs of the mosquito Psorophora confinnis. To date (September 2000) it has had 62 continuous passages. This is the first report of a cell line of mosquitoes belonging to the genus Psorophora. Cell growth initially was achieved in the MM/VP12 medium, supplemented with 20% fetal bovine serum; however, the subcultures were later adapted to Grace's medium with 10% fetal bovine serum. Cell morphology in the primary cultures was heterogeneous; but later in the established cell line, the predominant cell type was epithelioid. Cultured cells were predominantly diploid (2n=6); however, chromosome abnormalities were observed in a small proportion of the cells in later passages. C and G band patterns were also determined in the karyotype. The cell line isozyme profiles coincided with pupae and adult samples of the species taken from the same colony. A preliminary arbovirus susceptibility study for the cell line was undertaken. No evidence was observed of contamination of the cell line with bacteria, fungi or mycoplasma. (+info)
Identification of arboviruses and certain rodent-borne viruses: reevaluation of the paradigm.
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Diagnostic and epidemiologic virology laboratories have in large part traded conventional techniques of virus detection and identification for more rapid, novel, and sensitive molecular methods. By doing so, useful phenotypic characteristics are not being determined. We feel that the impact of this shift in emphasis has impaired studies of the biology of viruses. This position paper is a plea to the scientific and administrative communities to reconsider the importance of such information. We also suggest a revised paradigm for virus isolation and characterization and provide a rationale for accumulating biologic (phenotypic) information. (+info)
Protein synthesis in Bunyamwera virus-infected cells.
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In Vero cells infected with Bunyamwera virus there is a rapid inhibition of cell RNA and protein synthesis to levels of 30 and 3% respectively of the control rate, both the rate of inhibition and the time lag before its initiation being multiplicity dependent. Using u.v.-irradiated virus, investigation of the mechanism of inhibition of host cell protein synthesis indicates that synthesis of new virus components is required for inhibition to occur. Quantitative comparison of the proteins synthesized in infected cells shows that at higher m.o.i. synthesis of virus, as well as cellular proteins, is inhibited. Bunyamwera virus-infected Vero cells synthesized three virus-specific proteins identified as the structural virion proteins. Nucleoprotein is synthesized predominantly early in infection while the major envelope glycoprotein and the minor glycoprotein are synthesized predominantly late in the infection cycle. (+info)
Ribonucleoproteins of Uukuniemi virus are circular.
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The internal ribonucleoprotein (RNP) of Uukuniemi virus was released with Triton X-100 and analyzed on sucrose gradients. Three species of RNP sedimenting at 140 to 150, 105 to 120, and 85 to 90S could be separated. All of them contained the same ratio of core polypeptide (mol wt, 25,000) to RNA. Eelctron microscopy using rotatory shadowing showed that all three species were circular. Free ends were rarely seen. Measurements of the strands revealed three distinct length classes of about 2.8, 1.4 and 0.7 mu m. Polyacrylamide-agarose gels showed that the largest RNP contained the L RNA, the medium-sized RNP the M RNA, and the smallest RNP the S RNA. (+info)
Comparative studies of some African arboviruses in cell culture and in mice.
(21/307)
Twenty African arboviruses, five alphaviruses, nine flaviviruses, three Bunyamwera Group viruses, two Bwamba Group viruses and one ungrouped virus were titrated in parallel in 11 cell systems in suckling mice and adult mice. The relative sensitivities of the in vitro and in vivo systems have been compared. The highest infectivities were obtained in suckling mice. Vero and LLC-MK2 cells produced plaques with the greatest number of viruses and Semliki Forest virus grew most readily. Ntaya virus and Dengue 1 virus were difficult to culture in vitro and Zika virus yielded better in cell culture than in adult or suckling mice. In vitro and in vivo neutralization tests were made on human sera in groups of 50. Each group of sera was tested against one of five viruses, representative of three of the arbovirus groups titrated. Good agreement was obtained between the two test systems with West Nile, O'nyong-nyong and Wesselsbron viruses but there were significant differences in results obtained with Germiston and Pongola viruses. (+info)
The pathogenesis and pathology of experimental Quaranfil virus infection.
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Mice were infected intranasally with Quaranfil arbovirus, and killed at intervals from 1 day to 2 months later. The infection produced clinical signs of neurological disturbance and a highly mortality. The virus could be isolated from the lungs on Days 1-9 and from the brain on Days 1-11 of the infection. Meningoencephalitis developed by Day 5 in the olfactory lobes and spread progressively caudally, involving all regions of the brain by Day 7. The prinicipal features of the inflammatory process were perivascular cuffing, necrosis of neurones, and, in the later stages, spongiform degeneration and marked astrocytic and microglial activity. In the lungs after a short and mild exudative phase interstitial pneumonia developed. This was characterized by proliferation of connective tissue cells in interalveolar septa and later by fibrosis. (+info)
Serological survey of Toscana virus infections in a high-risk population in Italy.
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Toscana virus is the most important agent responsible for meningitis in central Italy. We report a serosurveillance study, using an immunoenzymatic assay, of 360 serum samples harvested from a high-risk population occupationally exposed to Toscana virus in two regions of Italy, Tuscany and Piedmont. The results indicates a seroprevalence of Toscana virus of 77.2% in the forestry workers, particularly in the Tuscany region. This fact is strictly correlated with the ecological niches specific for the survival of Toscana virus arthropod vector. (+info)
TICK-BORNE VIRUSES. A REVIEW OF AN ARTHROPOD-BORNE VIRUS PROBLEM OF GROWING IMPORTANCE IN THE TROPICS.
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More than 150 arthropod-borne viruses are now recognized, and over 50 of these are known to produce human infections and disease. Among these viruses are those of the tick-borne Russian spring-summer complex, which is etiologically involved in a wide variety of human diseases of varying severity. The eight antigenically different members of this complex so far known are Russian spring-summer encephalitis, louping-ill, Central European encephalitis, Omsk haemorrhagic fever, Kyasanur Forest disease, Langat, Negishi and Powassan viruses.In his review of the problems posed by these viruses and of research on them, the author points out that, while this complex is distributed around the globe in the temperate zone of the northern hemisphere, the only serious tick-borne virus disease known in the tropics is Kyasanur Forest disease. It is probable, however, that there are other, unrecognized tick-borne viruses in the tropical areas of Asia, Africa and America of importance to human health, and that these will be brought to light as virological studies of diseases of now obscure etiology are pursued. (+info)