Page 266 - AIDSBK23C

Page 266

DISINFECTION PROCEDURES

Retroviruses, including HIV, are extremely susceptible to environmental degradation.
The titer of HIV is reduced from 90 to 99% within several hours after drying, though both HIV
and hepatitis B virus have been found to persist on dry environmental surfaces for at least 7
days.[1077] HIV is highly susceptible to common routine chemical disinfectants and fixatives
used in medical practice. These include quaternary ammonium compounds, isopropanol
(rubbing alcohol), ethanol, hydrogen peroxide, sodium hypochlorite (bleach), cytologic
specimens received in 95% ethanol, tissues received in a formalin-containing fixative (such as
10% (v/v) neutral buffered formalin, Zenker's, B-5, or Bouin's fixatives), and glutaraldehyde.
0
Heat treatment of serum specimens at 56 C for 10 minutes also inactivates
HIV.[1078,1079,1080] Pasteurization of human breast milk has been demonstrated to inactivate
0
HIV.[1081] Pasteurization by heat treatment for 10 hours in a stabilized aqueous solution at 60
C will inactivate not only HIV, but also hepatitis A virus, hepatitis B virus, and hepatitis C virus
in human plasma derivatives.[1082]
Table 9 details many commonly available disinfectants and/or laboratory reagents
effective against HIV. Recommended concentrations of these agents are based upon a sufficient
safety margin, given additional factors of absorption, dilution, evaporation, or other loss of
potency in the application of these disinfectants.[1080] One reason for the relatively poor
7
infectivity of HIV from contact in the environment is that in blood there are only about 10 /L
16
infective HIV virions as compared to 10 /L infective hepatitis B virions.[1079]
Highly concentrated retroviral preparations can have recoverable virus after more than 1
0
week in an aqueous environment at temperatures ranging from room to body temperature (23 C
0
0
to 37 C). Five hours of heating to 56 C are needed to eliminate HIV in aqueous solutions.
Lipid enveloped viruses such as HIV may persist for one week of drying at room temperature.
Use of 0.1% NaOH, 0.1% hypochlorite, or 80% ethanol may not inactivate such dried viruses,
though rehydration helps disinfection. Thus, spills of body fluids and specimen bottles or
containers contaminated with patient fluid or tissue should be disinfected with 0.5% hypochlorite
(bleach). Work areas can be routinely disinfected with the same solution. Equipment or surfaces
sensitive to bleach can be cleaned with alternative disinfectants.[170,1078,1079,1080]