In the present research we considered
the possibility of in situ infection, and tested for
infection by adding a tissue suspension made from oysters
with the disease to tanks holding disease-free pearl oysters.
As the control group not given the suspension did not
contract the disease even in the laboratory experiment at a
constant temperature of 25 °C, we determined that the test
oysters were not originally challenged with the disease.
Our experiment confirmed that the oysters were infected
and contracted the disease because of addition of the
minced adductor suspension.