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Churchill County (Fallon)
Childhood Leukemia
Background
The cluster of childhood leukemia
cases was brought to the attention of Nevada public health
officials in the late summer of 2000, when it was learned
that five cases of Acute Lymphocytic Leukemia (ALL) had been
diagnosed in Churchill County within a few months of each
other. The Health Division immediately consulted with the
Centers for Disease Control and Prevention (CDC) on
appropriate steps for an investigation. To date, sixteen
children have been diagnosed with ALL and one with Acute
Myelocytic Leukemia (AML), all of whom lived in Churchill
County for varying lengths of time prior to diagnosis. Dr.
Randall Todd, State Epidemiologist, noted that based on
cases reported to the Nevada Central Cancer Registry, an
average rate of Acute Lymphocytic Leukemia is about 3
childhood cases per 100,000 children. This suggests that one
case would be expected about every five years in Churchill
County based on the size of the population.
The first phase of the investigation
commenced in September 2000 and involved interviewing each
of the case families to determine where they had lived, how
the water was supplied to those households, what sources of
water were used for drinking and cooking, household chemical
exposures, parental occupation and associated chemical
exposures, military history, and family medical history.
This information was used to learn if there were any common
characteristics present among all or most of the case
families.
In February 2001, the Nevada State
Health Division initially convened an Expert Review
Committee to look at the data collected to that point in
time and develop recommendations for subsequent steps in the
investigation. Attending were experts from the federal
Centers for Disease Control and Prevention (CDC), National
Cancer Institute (NCI), University of California, Berkeley,
University of Minnesota, University of Nevada School of
Medicine, representatives from Governor Guinn’s office,
Senator Ensign and Senator Reid’s offices. The agenda for
the one-day session was to review epidemiological
information gathered to date. Experts with considerable
experience in pediatric oncology, health effects of arsenic,
and investigation of leukemia clusters were in attendance.
Immediately following the conference, committee members
traveled to Fallon, Nevada to meet with case families.
In March 2001, the Expert Review
Committee provided a report in which they recommended that
the Health Division conduct a cross-sectional exposure
assessment and an environmental pathways study in
conjunction with scientists at the CDC and Agency for Toxic
Substances and Disease Registry (ATSDR). The Health Division
extended invitations to these agencies immediately upon
receipt of the report.
In July 2001, the Nevada State Health
Division reconvened the Expert Review Committee in Fallon,
Nevada. Prior to this second meeting, the committee was
expanded to include additional medical expertise as well as
representation from the case families and the community at
large. These additional members allowed scientific experts
to gain additional perspective and allowed the committee to
evolve into an Advisory Committee. The Advisory Committee
reviewed protocols developed by the Centers for Disease
Control and Prevention (CDC) and the Agency for Toxic
Substances and Disease Registry (ATSDR).
In August 2001, the Institutional
Review Board (IRB), at the CDC, approved the protocols for
human testing. Immediately, plans for environmental and
biological testing were finalized. In September 2001,
biological testing began in Churchill County. Two weeks
later, environmental testing of water, soil, dust, air was
started.
Churchill Community Hospital
graciously provided clinical facilities to conduct testing
in Churchill County. Laboratory equipment was ordered and
shipped to the facility located in Fallon, Nevada at
Physicians Center North. The testing focused on two areas:
biological and environmental. CDC selected comparison
(control) families and enrolled case families in the
cross-sectional exposure assessment. In this way, case
families were compared with other families in the Churchill
County community not affected with leukemia. If, after
testing was completed, we found high levels of one substance
among case families, but not control families, this may have
provided important clues in identifying potential causal
factors. In October 2001, CDC completed the collection of
biological specimens. The Nevada Division of Environmental
Protection (NDEP) completed collection of environmental
samples in November 2001. The biological specimens were then
analyzed at CDC. The environmental samples were being
analyzed in several laboratories throughout the nation.
Results from both the CDC and ATSDR
studies were presented to the Churchill County community at
town hall meetings in February 2003. These results are
summarized on the CDC and ATSDR web sites. Members of the
Expert Panel presented the final report to the community in
February 2004.
To view the Expert Review Committee
Report click here
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