NMFS NUMBER: 93-WO-044
Potential, Tissue Distribution and Survival in Molluscan
Shellfish of Putative Norwalk-like Caliciviruses Originating
from Ocean Hosts
Smith, Professor Alvin W.
March 21, 1997
National Marine Fisheries Service, 219 Fort Johnson Road,
Charleston, SC 29412. PHONE: (803) 762-1200
was to develop extraction and assay methods for recovering
known caliciviruses from various tissues of shellfish
given a measured quantity of virus, and to test for calicivirus
replication in shellfish exposed to various known caliciviruses.
Molluscan shellfish are known to be contaminated
with several potential human pathogens including the caliciviruses,
which have been implicated in severe outbreaks of viral
gastroenteritis. Lack of specific, reliable tests
for caliciviruses and other pathogens has resulted in
shellfish waters being closed to harvesting because the
status of contamination could not be determined.
Furthermore, decontamination methods of relaying and depuration
have proven to be inadequate for insuring the safety of
raw shellfish contaminated with caliciviruses. Under
this project, caliciviruses were isolated from naturally
and experimentally exposed shellfish stocks using mammalian
cell culture systems. Retention (and possible replication)
of these viruses in shellfish was demonstrated for 60
days or more under depuration using continuous flow sterile
sea water. The project also demonstrated that caliciviruses
occur naturally within ocean sources including shellfish,
and identified calicivirus contamination in both open
and closed shellfish beds on all coasts ( Atlantic, Gulf,
and Pacific), although the source of these viruses (marine
and terrestrial) remains unknown.