Studies on Cotia virus--an unclassified poxvirus

This paper is a report of studies on Cotia virus; this had been first isolated in 1965 in Brazil and was subsequently shown to be a poxvirus. Cotia virus grew in a wide range of cell cultures and on the chick chorioallantois (CAM), Its growth characteristics are similar to those of other poxviruses. Microscopy showed virus factories or type B inclusions appearing before infectious progeny virus could be demonstrated. Type A inclusions appeared later, after development of progeny virus; these were shown by electron microscopy to differ from the type A inclusions of cowpox and other poxviruses and they have been termed Cotia bodies. Immunofluorescent staining also showed ring structures which appeared before the development of Cotia bodies. The growth of Cotia virus in human embryo lung (HEL) cells was sensitive to inhibitors of DNA and protein synthesis but was resistant to a concentration of rifampicin which inhibited vaccinia virus. Sharing of antigens between the Cotia virus and vaccinia virus was shown by gel precipitation tests and immunofluorescent staining. There was no cross neutralization between Cotia virus and vaccinia virus nor did anti-Cotia sera neutralize representatives of other poxvirus groups.