CORONA VIRIDAE-Properties of Coronaviridae

 

            Colds are readily transmissible to human volunteers by intranasal administration of human coronaviruses. After an incubation period of 2-5 days, symptoms
develop in about half of those inoculated, and virus is shed for about a
week.
Coronaviruoids  occur mainly in the winter and early spring. A longitudinal
study in the United States indicated that large outbreaks of either 229E
or 0C43 infection tend to occur with a periodicity of 2-4 years. Adults are
affected as well as children because acquired immunity is so ephemeral. Overall,
it is estimated that coronaviruses are responsible for about 15% of a11
colds.
The role, if any, of enteric coronaviruses and  toro viruses in human
gastroenteritis remains uncertain. Transmission is presumably by the fecal,oral
route.
The readers of this book will, I hope, appreciate that considerable progress
has been made in elucidating many aspects of coronavirus and torovirus biology
in a relatively short time. However, there remain many unanswered questions,
particularly in areas such as the genesis of corona- and torovirus subgenomic
mRNAs, the structure and function of the viral nonstructural proteins, and the
pathogenesis of natural infections. I hope that reading this book may stimulate
young scientists to address some of these questions.