
The problem with animal cells is that during serial
passage of the virus thru
the animal cells, is that animal RNA and DNA
can be transferred from one
host to another and undetected animal viruses
may slip past quality control
testing procedures as in 1955 thru 1961 withSV40
which stands for simian
virus#40 (meaning the 40th virus found) which
has oncogenic properties
(cancer causing)
What other viruses could be slipping by that we
don't know of?