Review of the Churchill County, NV ALL cluster, 1997-2004.

Between 1997 and 2002, 16 cases of acute childhood leukemia were diagnosed in children who either lived in Churchill County, Nevada at the time of diagnosis or had lived in the county before their diagnosis. The cases were characterized as a cluster of like illnesses and the probability of having such a cluster occur by chance was estimated to be very small (approximately one in 2.33×10(8)). This suggested that the cluster could be linked to one or more physical, limnological, chemical, or biological agents. This review discusses the setting in which the cluster took place, the epidemiological investigations carried out by the Nevada Bureau of Health Protection Services, the National Center for Environmental Health Centers for Disease Control and Prevention and the Agency for Toxic Substances and Disease Registry, and subsequent investigations supported by a special allocation of federal funds through the US Environmental Protection Agency's Region IX office in San Francisco, CA. This review is meant as background for the papers in this special issue that report results from multi- and interdisciplinary research into environmental and biological factors potentially related to the Churchill County leukemia cluster.