Anonymous Survey for Simian Immunodeficiency Virus (SIV)
Seropositivity in SIV-Laboratory Researchers -- United States, 1992
CDC recently reported on two laboratory workers who had
seroconverted against simian immunodeficiency virus (SIV) following
work-related exposure to the virus (1). In follow-up, the National
Institutes of Health (NIH) and CDC have collaborated on an
anonymous SIV seroprevalence study using stored serum samples from
some laboratory workers and animal caretakers involved in SIV
research at some of the NIH-sponsored facilities in the United
States. This report summarizes the study.
A convenience sample of serum specimens previously collected
from researchers and stored at -4 F (-20 C) were forwarded without
any identification of the employee or research facility to CDC
through a contract laboratory. Eleven serum specimens known to be
seropositive for either human immunodeficiency virus type 1 (HIV-1)
or human immunodeficiency virus type 2 (HIV-2) were included in the
group of specimens as positive controls. A total of 483 serum
samples (including the 11 controls) were screened blindly at CDC
using a combination HIV-1/2 peptide-based enzyme-linked
immunosorbent assay (ELISA) (Biochemical Immunogenetics,
Montreal *). Repeatedly reactive samples were tested by HIV-1 and
HIV-2 Western blot and by HIV-1 and HIV-2 peptide-based ELISA
assays (Biochemical Immunogenetics; Genetic Systems, Seattle; and
in-house). Because of the high degree of serologic cross-reactivity
between HIV-2 and SIV, seropositivity to HIV-2 was considered to
indicate the presence of antibody to either virus. All 11 control
serum samples tested positive for either HIV-1 or HIV-2/SIV.
Three of the 472 samples tested were seropositive for
HIV-2/SIV. An additional two samples had antibody to HIV-1.
Reported by: National Institutes of Health. Retrovirus Diseases Br,
Div of Viral and Rickettsial Diseases, and Laboratory
Investigations Br, Div of HIV/AIDS, National Center for Infectious
Diseases, CDC.
Editorial Note
Editorial Note: This blinded serosurvey was undertaken to rapidly
estimate the prevalence of seroreactivity to SIV among laboratory
workers and animal caretakers involved in SIV research. The
findings indicated a low seroprevalence of HIV-2/SIV antibody
(0.6%). However, the three SIV-seropositive persons in this blinded
study may include one or both cases reported previously by CDC.
Moreover, because of the high degree of cross-reactivity between
HIV-2 and SIV, it is possible that these persons may be
seropositive for HIV-2 rather than SIV.
Because HIV-1 shows some cross-reactivity with HIV-2, HIV-1
testing was conducted as a necessary part of this study. However,
the two HIV-1-seropositive persons in this anonymous study cannot
be identified or notified; these persons may be aware of their
HIV-1 status.
To address concerns about the potential for transmission of
SIV in research laboratories, NIH and CDC are planning to add
voluntary testing for SIV to their existing medical surveillance
programs. In addition, NIH and CDC are planning a collaborative
prospective study to investigate SIV seropositivity among animal
caretakers and laboratory workers in federally funded SIV-research
laboratories to identify specific exposures associated with
seropositivity. Based on CDC's investigation of the two previously
reported cases (1) and the findings reported in this study, all
laboratory and animal workers involved in SIV research should
strictly adhere to recommended procedures for handling known and
potentially SIV-infected clinical samples (2).
References
CDC. Seroconversion to simian immunodeficiency virus in two
laboratory workers. MMWR 1992;41:678-81.
CDC. Guidelines to prevent simian immunodeficiency virus
infection in laboratory workers and animal handlers. MMWR
1988;37:693-4,699-704.
Use of trade names and commercial sources is for identification
only and does not imply endorsement by the Public Health Service or
the U.S. Department of Health and Human Services. The peptide-based
assays used in this study are unlicensed by the Food and Drug
Administration for diagnostic purposes; however, they were used
here because they are highly sensitive for HIV-2/SIV.
Disclaimer
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