RESUMO
Several groups of variola isolates were compared in DNA structure, and by four independent biologic markers. Isolates of variola minor from Europe and South America (alastrim virus) could be distinguished from African isolates of variola minor by DNA structure and by two of the four biologic markers. Taken as a group, the properties of African isolates, in general, differed from those of variola major, but this difference was confined to properties which depended (in the laboratory) on the recent history of the virus concerned. The suggestion made previously that there was an "intermediate" or "African" variety of variola virus is discounted. Laboratory tests did not distinguish any individual African isolate from variola major virus. It is concluded that a virus which may be called "alastrim" represents a "fixed" variant of variola virus, whose distribution is consistent with the dramatic spread of variola minor through the Americas and Europe in the early part of this century, and that variola minor in Africa in recent years was due to variola virus which was not alastrim and which laboratory evidence fails to identify as an entity distinguishable from variola major virus.
Assuntos
Varíola/microbiologia , Vírus da Varíola/patogenicidade , África Ocidental , Animais , Botsuana , Linhagem Celular , Embrião de Galinha , DNA Viral/genética , Europa (Continente) , Marcadores Genéticos , Hemadsorção , Testes de Hemaglutinação , Hemaglutininas Virais/análise , Humanos , América do Sul , Vírus da Varíola/classificação , Vírus da Varíola/genética , Vírus da Varíola/isolamento & purificação , VirulênciaAssuntos
Varíola/epidemiologia , Vírus da Varíola/imunologia , África , Animais , Ásia , Embrião de Galinha , Haplorrinos , Humanos , Imunidade , Sorotipagem , Varíola/classificação , Varíola/transmissão , América do Sul , Reino Unido , Vírus da Varíola/classificação , Vírus da Varíola/patogenicidade , Virulência , ZoonosesRESUMO
The author presents data indicating that three species of New World monkeys (Cebus apella, Ateles paniscus, Lagothrix lagothricha) are not susceptible to Brazilian variola minor. Although the number of animals tested was not large, no experimental evidence was obtained to suggest that these species could form a non-human reservoir for smallpox in the Western Hemisphere. The results also indicate that Cercopithecus aethiops are not very susceptible to infection with either variola major or minor. Haemagglutination-inhibition tests of sera from monkeys from South America, Africa and the Philippines failed to reveal significant levels of poxvirus antibody. Previous studies have shown that Macaca irus, although susceptible to experimental infection with variola major, are not able to maintain the infection for more than a few generations of disease. The author concludes that there is as yet no clear experimental, serological or epidemiological evidence to support the hypothesis that smallpox can exist in wild simian populations.