Am

Am. the filter. Organisms attached to the filter also tested positive by PCR. The two samples that tested unfavorable for were one that was obtained from a kitchen sink trap and a swipe sample from the garbage disposal of one home. The genus is composed of a NSC139021 group of free-living amoeboflagellates that are distributed worldwide. Although several species have been identified, only one, is the causative agent of primary amoebic meningoencephalitis (PAM), a fatal disease of the central nervous system (8, 26, 29, 30, 44). has been isolated from a variety of water Tead4 sources, including domestic water supplies (1-3, 8, 10, 16), recreational water facilities (6, 7, 9, 11, 19, 20, 43, 45, 46), and thermally polluted water from industrial sources (13, 21, 36, 42). The presence of in environmental water has been linked to heat, pH, coliforms, and the amount of organic matter present (17, 18, 36). Iron and iron-containing compounds in water favor growth of (22). Although PAM is not common, cases of the disease have been reported in almost every continent. Indoor swimming pools have been the source of PAM in Czechoslovakia (9). In Mexico, five cases of PAM were associated with swimming in shallow water in an artificial canal (23). In South Australia, cases of PAM have occurred through the domestic water supply. These cases occurred during the summer months in children submerged in bathtubs and wading pools (1-3, 16, 31). In Great Britain, PAM was acquired from mud puddles in which children played after a heavy rainstorm (4). The majority of cases of PAM have been reported in the United States, and these cases have occurred in previously healthy young adults and children associated with water sports (7, NSC139021 12, 14, 15, 19, 28-30, 40, 45). The presence of in the environment may present a risk to human health. Indeed, there has been an increase in the number of cases of PAM reported in recent years (25). The correct identification of is usually difficult because NSC139021 several genera of amoebae found in the same ecological habitat are morphologically comparable (33, 39). Furthermore, pathogenic and nonpathogenic are antigenically related (39). Therefore, a sensitive and specific nested-PCR assay was developed in our laboratory to identify in water and soil samples (35; R. MacLean, D. J. Richardson, R. LePardo, and F. Marciano-Cabral, submitted for publication). The nested-PCR assay has been used previously to document the occurrence of in environmental samples collected in Connecticut and Virginia (MacLean NSC139021 et al., submitted). In the present study, 19 samples were collected from sources in homes associated with the deaths of two children from PAM in Arizona. Samples were cultured on nonnutrient agar made up of or in liquid medium and tested for by nested PCR. Thermotolerant amoeboflagellates were observed by light microscopy in liquid cultures. was detected by nested PCR in swipe samples from sink traps, in residual pipe water, and from a Micro-Wynd filter which was used to filter bathtub water in the homes of victims of PAM. MATERIALS AND METHODS Study area and collection sites. Swipe samples from sink traps and residual water present in pipes were collected from the homes associated with two cases of PAM and from the home of an adjacent neighbor. The domestic water NSC139021 was supplied by a private water company in Arizona directly from a well or a holding tank, depending on the demand in the system. Disinfection of the water supply by methods of chlorination, ozone or UV light treatment, or filtration did not occur at the time of the incidents. Swipe samples from the victims’ homes were obtained by passing sterile cotton gauze Mirasorb sponges through the kitchen and bathroom.