Biosafety Guidelines For Research On Genetically Modified ...

4. Procedures for handling viruses that can potentially infect human cells
(‘human infectious’ viruses)
The primary hazard associated with the use of live recombinant viruses that have
the capacity or that could potentially infect human cells lies on the type of the viruses
and the nature of the introduced genetic sequences. Primate-infectious viruses shall
be considered “potentially human-infectious”. For all human-infectious viruses
handled in a class II biological safety cabinet, the primary hazard to the scientist is
the possibility of infection by viruses through broken skin brought about by needles
and other commonly used sharps such as pipettes. The potential danger to other
laboratory personnel depends on the stability and infectivity of the virus in the
extracellular environment and the nature of the introduced genetic material.
For all human-infectious or potentially human-infectious viruses, the major
requirement is for good virological and tissue culture practice on the part of the
scientist with regard to the following precautions:
(a) A facility of containment of level BSL2 or higher (as determined by the IBC and
with reference to the Biosafety level detailed by the ATCC and CDC) will be
required. All manipulations shall be conducted in a class II biological safety
cabinet or equivalent. Only one individual shall use the cabinet at any one time.
(b) Laboratory gowns, gloves and face mask shall be worn during manipulations
with recombinant human-infectious viruses.
(c) Dishes and plates of cells containing human-infectious viruses shall be handled
in larger plates (or inverted lids) to provide traps for accidental spills.
(d) All pipettes, glassware and plasticware shall be decontaminated by submersion
or by placing in polyethylene bags which should subsequently be sealed and
autoclaved.
(e) For viruses which are able to persist in the environment (e.g. adenovirus,
vaccinia virus, hepatitis virus, papillomavirus), decontamination and bagging of
waste should be done within the biosafety cabinet prior to removal and
autoclaving. Care should be taken to ensure that the amount of material held in
the biosafety cabinet is minimised, in order to avoid interference with the air flow
in the cabinet.
(f) Mouth pipetting is strictly prohibited.
(g) Open flames that could interrupt the air-flow in the biosafety cabinet should be
avoided.
(h) The use of sharp instruments (sharps) such as syringe needles, glass pipettes,
razors, scissors and surgical knives, wherever possible, should be avoided,
since skin abrasions represent the most likely portal of entry to the body.
Where the use of sharps is unavoidable, these instruments shall be placed in
separate biological disposal receptacles and sterilized before disposal.
(i) Tissue cultures infected with human-infectious or potentially human-infectious
viruses shall be kept in specially dedicated incubators.
(j) Likewise, frozen stocks of human-infectious or potentially human-infectious
viruses should be kept in specially designated and clearly marked liquid nitrogen
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