Recombinant DNA Advisory Committee - 06/7-8/93 
downplay the potential pathogenicity of this virus. Two ad hoc reviewers have also 
submitted written critiques of the proposal. The ad hoc reviewers, Dr. Alan L. 
Schmaljohn of U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick 
at Frederick, Maryland, and Dr. Dennis W. Trent of National Center for Infectious 
Diseases, Fort Collins, Colorado, recommended use of this system at BL2 containment, 
however, they also emphasized the necessity to exercise caution. 
Ms. Meyers inquired whether SFV is infectious to animals. Dr. Miller responded that it 
is possible that SFV can be transmitted by mosquitos from humans to animals, causing 
the virus to become endemic in the region. 
Review-Dr. Post 
Dr. Post stated that there is no valid scientific reason for classifying SFV and Sindbis 
virus in different containment categories. It appears that the classification of SFV at the 
BL3 containment level resulted from a single fatal case report. This case involved a 
subject suffering from chronic bronchitis and a strain of SFV that was unnaturally 
passaged through animals. Considering the long-term safe laboratory use with SFV and 
the epidemiological data about the natural infection of humans, SFV should not be 
considered a particularly virulent agent. The vector proposed by Life Technologies, Inc., 
is a disabled version of the wild-type virus. He said that he would vote to approve the 
request to reclassify this cloning vector system for use at BL2 provided that the 
applicants supply proper instructions for the safe handling of this vector cloning system. 
Other Comments 
Dr. Parkman asked whether this virus can be easily inactivated. Dr. Straus responded 
that it is easily inactivated and should not be an issue; however, he has serious concern 
about the general use of this virus by nonvirologists who are inexperienced at handling 
viral agents. The history of the safe use of SFV at BL2 in the past involved virologists 
experienced with use of these viruses. Dr. Straus was concerned that when the cloning 
vector is marketed, it will be used by laboratory personnel who do not have proper 
virology training. 
Investigator Response-Dr. Temple 
In response to Dr. Krogstad's question of seroconversion. Dr. Temple said that in Dr. 
Robert E. Shope's laboratory at Yale University, 2 out of 15 laboratory workers 
demonstrated borderline conversion; and in Dr. L. Kaariainen's laboratory at the 
University of Helsinki in Finland, 8 out of 16 laboratory workers were seropositive for 
SFV. These two laboratories all performed their experiments at BL2 containment. 
Regarding Dr. Miller's interpretation of the recombination frequency, Dr. Temple said 
Recombinant DNA Research, Volume 17 
[591] 
