Table 11 
Results of 1979 SALS Survey 
for SFV 
Facility 
Level 
No. Labs 
No. Workers 
Exposed 
Total 
Exposure 
Experience^ 
(%) 
Avg. Expos, 
per Worker* 10 
Overt Lab 
Infection 
Inapparent 
Infection 
1 
6 
28 
303 (15) 
10.8 
0 
0 
2 
9 
87 
1675 (83) 
19.3 
|(c) 
o (d) 
3 
1 
25 
50 (2) 
2.0 
0 
0 
4 
0 
0 
0 
TOTAL 
16 
140 
2028 
14.5 
•Exposure experience = (number of laboratory workers exposed to SFV) X (minimum number 
of exposures) calculated separately for each laboratory). 
b Average exposure per worker = (Total exposure experience) -r (number of workers exposed). 
Exposure experience was rated as 1 (if a worker handled SFV once), as 2 (for two to twenty 
times) or as 21 (for greater than twenty times). 
Patient died of SFV encephalitis. 
d l of 2 persons tested was seropositive, in same laboratory as c. 
The SALS data do not provide a complete record of the serological status of SFV 
laboratory workers, however, as sera generally were not sampled without signs 
of an overt infection or accident. To assess the frequency of inapparent SFV 
infections, serological surveys of laboratory workers exposed to SFV are needed. 
Recombinant DNA Research, Volume 18 
[469] 
