<s>
Disinfectant	B-Application
was	O
a	O
popular	O
antivirus	B-Application
software	I-Application
program	O
for	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
.	O
</s>
<s>
It	O
was	O
originally	O
released	O
as	O
freeware	B-License
by	O
John	O
Norstad	O
in	O
the	O
spring	O
of	O
1989	O
.	O
</s>
<s>
Disinfectant	B-Application
featured	O
a	O
system	B-Operating_System
extension	I-Operating_System
that	O
would	O
detect	O
virus	O
infections	O
and	O
an	O
application	O
with	O
which	O
users	O
could	O
scan	O
for	O
and	O
remove	O
viruses	O
.	O
</s>
<s>
New	O
versions	O
of	O
Disinfectant	B-Application
were	O
subsequently	O
released	O
to	O
detect	O
additional	O
viruses	O
.	O
</s>
<s>
Bob	O
LeVitus	O
praised	O
and	O
recommended	O
Disinfectant	B-Application
in	O
1992	O
.	O
</s>
<s>
In	O
May	O
1998	O
,	O
Norstad	O
retired	O
Disinfectant	B-Application
,	O
citing	O
the	O
new	O
danger	O
posed	O
by	O
macro	B-Application
viruses	I-Application
,	O
which	O
Disinfectant	B-Application
did	O
not	O
detect	O
,	O
and	O
the	O
inability	O
of	O
a	O
single	O
individual	O
to	O
maintain	O
a	O
program	O
that	O
caught	O
all	O
of	O
them	O
.	O
</s>
