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The incidence of legionellosis, caused by the bacteria Legionella which are commonly found in the environment, has been increasing in New Jersey (NJ) over the last decade. The majority of cases are sporadic with no known source of exposure. Meteorological factors may be associated with increases in legionellosis. Time series and case-crossover study designs were used to evaluate associations of legionellosis and meteorological factors (temperature (daily minimum, maximum, and mean), precipitation, dew point, relative humidity, sea level pressure, wind speed (daily maximum and mean), gust, and visibility). Time series analyses of multi-factor models indicated increases in monthly relative humidity and precipitation were positively associated with monthly legionellosis rate, while maximum temperature and visibility were inversely associated. Case-crossover analyses of multi-factor models indicated increases in relative humidity occurring likely before incubation period was positively associated, while sea level pressure and visibility, also likely preceding incubation period, were inversely associated. It is possible that meteorological factors, such as wet, humid weather with low barometric pressure, allow proliferation of Legionella in natural environments, increasing the rate of legionellosis.

Background: Limited epidemiological data exist about amyotrophic lateral sclerosis (ALS) in the United States (US). The Agency for Toxic Substances and Disease Registry maintains the National ALS Registry and funded state and metropolitan surveillance projects to obtain reliable, timely information about ALS in defined geographic areas. Methods: Neurologists submitted case reports for ALS patients under their care between January 1, 2009 and December 31, 2011 who were New Jersey residents. A medical record verification form and electromyogram (EMG) report were requested for a sample of case reports. Incidence rates were standardized to the 2000 US Standard Population. Results: The average crude annual incidence rate was 1.87 per 100,000 person-years, the average age-adjusted annual incidence rate was 1.67 per 100,000 person-years, and the point prevalence rate on December 31, 2011 was 4.40 per 100,000 persons. Average annual incidence rates and point prevalence rates were statistically higher for men compared with women; Whites compared with Blacks/African Americans and Asians; and non-Hispanics compared with Hispanics. Conclusions: The project findings contribute new, population-based, state-specific information to epidemiological data regarding ALS. The findings are generally consistent with previously published surveillance studies conducted in the US and abroad.

>A study of drinking water contamination and leukemia and non-Hodgkin's lymphoma (NHL) incidence (1979-1987) was conducted in a 75-town study area. Comparing incidence in towns in the highest trichloroethylene (TCE) stratum (>5 microg/l) to towns without detectable TCE yielded an age-adjusted rate ratio (RR) for total leukemia among females of 1.43 (95% CI 1.07-1.90). For females under 20 years old, the RR for acute lymphocytic leukemia was 3.26 (95% CI 1.27-8.15). Elevated RRs were observed for chronic myelogenous leukemia among females and for chronic lymphocytic leukemia among males and females. NHL incidence among women was also associated with the highest TCE stratum (RR = 1.36; 95% CI 1.08-1.70). For diffuse large cell NHL and non-Burkitt's high-grade NHL among females, the RRs were 1.66 (95% CI 1.07-2.59) and 3.17 (95% CI 1.23-8.18), respectively, and 1.59 (95% CI 1.04-2.43) and 1.92 (95% CI 0.54-6.81), respectively, among males. Perchloroethylene (PCE) was associated with incidence of non-Burkitt's high-grade NHL among females, but collinearity with TCE made it difficult to assess relative influences. The results suggest a link between TCE/PCE and leukemia/ NHL incidence. However, the conclusions are limited by potential misclassification of exposure due to lack of individual information on long-term residence, water consumption, and inhalation of volatilized compounds.

Residential clusters of non-communicable diseases are a source of enduring public concern, and at times, controversy. Many clusters reported to public health agencies by concerned citizens are accompanied by expectations that investigations will uncover a cause of disease. While goals, methods and conclusions of cluster studies are debated in the scientific literature and popular press, investigations of reported residential clusters rarely provide definitive answers about disease etiology. Further, it is inherently difficult to study a cluster for diseases with complex etiology and long latency (e.g., most cancers). Regardless, cluster investigations remain an important function of local, state and federal public health agencies. Challenges limiting the ability of cluster investigations to uncover causes for disease include the need to consider long latency, low statistical power of most analyses, uncertain definitions of cluster boundaries and population of interest, and in- and out-migration. A multi-disciplinary Workshop was held to discuss innovative and/or under-explored approaches to investigate cancer clusters. Several potentially fruitful paths forward are described, including modern methods of reconstructing residential history, improved approaches to analyzing spatial data, improved utilization of electronic data sources, advances using biomarkers of carcinogenesis, novel concepts for grouping cases, investigations of infectious etiology of cancer, and “omics” approaches.

During two legionellosis outbreak investigations, one at a geriatric centre and the other in high-rise housing for seniors, it was observed that additional cases of legionellosis occurred in nearby smaller residential settings. This apparent geographical cluster of legionellosis occurred in the same general area of a community water storage tank. No potential airborne sources in or near the area could be identified, but a community water system storage tank that was centrally located among case residences spurred an investigation of water-quality factors in the identified investigation area. Conditions conducive for Legionella growth, particularly low chlorine residuals, were found. The rate of legionellosis among residents aged ⩾50 years in the investigation areas (61·0 and 64·1/100 000) was eight times higher than in the rest of the service area (9·0/100 000) and almost 20 times higher than the statewide annual average incidence rate (3·2/100 000). A water mains flushing programme in the area was launched by the water utility, and water samples taken before and during flushing found L. pneumophila.

An ecologic study was performed to examine the relation between the incidence of leukemias and the occurrence of volatile organic chemical (VOC) contamination of drinking water supplies within a study area comprised of subpopulations differentially exposed to drinking water VOCs (trichloroethylene and related solvents). Populations served by community water supplies were classified into exposure categories according to VOC contamination status based on 1984-85 sampling data. Leukemia incidence data (1979-84) were collected from a population-based cancer registry. For females, the standardized incidence ratio was elevated only in towns in the highest ofthree exposure categories. No association was