Electron Microscopic Evidence of Nariva Virus Structure

Nariva virus was first isolated in 1962 by Tikasingh et al. (1966) from Trinidadian rodents Zygodontomys b. brevicauda and was originally thought to be an arbovirus. It contains RNA, is ether-sensitive and haemadsorbs guinea-pig erythrocytes (Karbatsos, Buckley & Ardoin, 1969). Few of its properties are known, and since its structure and morphogenesis are also unknown, its taxonomic position is uncertain. We describe here observations on the structure and morphogenesis of Nariva virus propagated in BHK 21 cell cultures, thus providing some evidence for its classification. Monolayers of BHK 21 cells were grown in EM/TPB medium as described previously by (Macpherson & Stoker, 1962) and maintained in equal parts of EM/TPB and Basal medium Eagle (Eagle, 1955) with 3% foetal bovine serum, 0.05% of 2 m-tris and antibiotics; kanamycin and tylosin tartrate was additionally added. Nariva virus (prototype strain trvl-42520, 4th mouse brain passage) was obtained from Dr L. Spence (Trinidad Regional Virus Laboratory, Trinidad).