A method for increasing the surface details of resin embedded viruses using Congo/Crimean haemorrhagic fever virus as a model.

The surface details of resin embedded viruses can be greatly enhanced by the use of uranyl acetate block staining. The virions are embedded in agar immediately after fixation and block stained with 3% uranyl acetate in methanol during dehydration. This technique allows those particles outside their host cells to show clearly the spikes normally seen only by the separate use of negative staining.

Electron microscopic demonstration of Crimean hemorrhagic fever virus in CV-1 cells.

Crimean hemorrhagic fever (CHF) virus was detected by electron microscopy in ultrathin sections of CV-1 cells. The virus particles appeared spherical or oval and occurred both intra- and extracellularly. Based on their size and density of their contents, two types of virions, probably representing different phases of the reproduction cycle of CHF virus, could be distinguished.

Crimean-Congo haemorrhagic fever virus in Iraq: isolation, identification and electron microscopy.

Crimean-Congo haemorrhagic fever (CCHF) virus was isolated for the first time in Iraq from the blood of three patients. It caused a cytopathic effect in lamb kidney and BHK-21 cell cultures. The virus particles were spherical, enveloped and had 90 nm in diameter similar particles were found in ultrathin sections of the liver from two fatal cases. The isolated virus proved to be antigenically closely related to CCHF virus.

Ex vivo stability of the rodent-borne Hantaan virus in comparison to that of arthropod-borne members of the Bunyaviridae family.

The possible effect of virus adaptation to different transmission routes on virus stability in the environment is not well known. In this study we have compared the stabilities of three viruses within the Bunyaviridae family: the rodent-borne Hantavirus Hantaan virus (HTNV), the sand fly-borne Phlebovirus sandfly fever Sicilian virus (SFSV), and the tick-borne Nairovirus Crimean-Congo hemorrhagic fever virus (CCHFV). These viruses differ in their transmission routes: SFSV and CCHFV are vector borne, whereas HTNV is spread directly between its hosts, and to humans, via the environment. We studied whether these viruses differed regarding stability when kept outside of the host. Viral survival was analyzed at different time points upon exposure to different temperatures (4 degrees C, 20 degrees C, and 37 degrees C) and drying at 20 degrees C. We observed clearly different stabilities under wet conditions, particularly at 4 degrees C, where infectious SFSV, HTNV, and CCHFV were detectable after 528, 96, and 15 days, respectively. All three viruses were equally sensitive to drying, as shown by drying on aluminum discs. Furthermore, HTNV and SFSV partially survived for 2 min in 30% ethanol, whereas CCHFV did not. Electron microscopy images of HTNV, SSFSV, and CCHFV stored at 37 degrees C until infectivity was lost still showed the occurrence of virions, but with abnormal shapes and densities compared to those of the nonincubated samples. In conclusion, our study points out important differences in ex vivo stability among viruses within the Bunyaviridae family.

Congo/Crimean haemorrhagic fever virus from Iraq 1979: I. Morphology in BHK21 cells.

Congo-Crimean Haemorrhagic Fever virus, isolated from a patient in Iraq, was grown, after passage in suckling mouse brain, in BHK cells. The particles matured after 8-9 days in these cells by budding, usually singly, into cytoplasmic vacuoles throughout the host cells. The virions had an overall diameter of 115 to 125 nm, including rounded surface spikes 15 nm long and 10 nm wide. The viral cores, surrounded by a lipid unit membrane, contained discrete electron-dense elements. It is suggested that the spikes, dimpled at their outer end and possibly hollow throughout their length, passed out through "pores" in the unit membrane.

Morphology and morphogenesis of Crimean hemorrhagic fever virus.

Morphological characteristics of Crimean Hemorrhagic Fever Virus indicate that it is closely related to the Bunyaviridae family. However, there are some features (e.g. formation of crystal-like patterns in infected cells) demonstrating differences to the other known Bunyaviridae.

Physicochemical characteristics, morphology and morphogenesis of virions of the causative agent of Crimean hemorrhagic fever.

Similar physicochemical characteristics were found with strains of Crimean hemorrhagic fever (CHF) and Congo viruses. The particle size, sedimentation coefficient, buoyant density, weight of the particles as well as morphology and morphogenesis of these viruses were similar to those of other members of the Bunyaviridae family. Data are presented on reproduction of CHF virus in cell cultures and on the inner structure of its virion.