Seasonality in six enterically transmitted diseases and ambient temperature.

We propose an analytical and conceptual framework for a systematic and comprehensive assessment of disease seasonality to detect changes and to quantify and compare temporal patterns. To demonstrate the proposed technique, we examined seasonal patterns of six enterically transmitted reportable diseases (EDs) in Massachusetts collected over a 10-year period (1992-2001). We quantified the timing and intensity of seasonal peaks of ED incidence and examined the synchronization in timing of these peaks with respect to ambient temperature. All EDs, except hepatitis A, exhibited well-defined seasonal patterns which clustered into two groups. The peak in daily incidence of Campylobacter and Salmonella closely followed the peak in ambient temperature with the lag of 2-14 days. Cryptosporidium, Shigella, and Giardia exhibited significant delays relative to the peak in temperature (approximately 40 days, P<0.02). The proposed approach provides a detailed quantification of seasonality that enabled us to detect significant differences in the seasonal peaks of enteric infections which would have been lost in an analysis using monthly or weekly cumulative information. This highly relevant to disease surveillance approach can be used to generate and test hypotheses related to disease seasonality and potential routes of transmission with respect to environmental factors.

Prolonged outbreak of giardiasis with two modes of transmission.

Large outbreaks of giardiasis caused by person-to-person transmission, or a combination of transmission routes, have not previously been reported. A large, prolonged giardiasis outbreak affected families belonging to a country club in a suburb of Boston, Massachusetts, during June-December 2003. We conducted a retrospective cohort study to determine the source of this outbreak. Giardiasis-compatible illness was experienced by 149 (25%) respondents to a questionnaire, and was laboratory confirmed in 97 (65%) of these cases. Of the 30 primary cases, exposure to the children's pool at the country club was significantly associated with illness (risk ratio 3.3, 95% confidence interval 1.7-6.5). In addition, 105 secondary cases probably resulted from person-to-person spread; 14 cases did not report an onset date. This outbreak illustrates the potential for Giardia to spread through multiple modes of transmission, with a common-source outbreak caused by exposure to a contaminated water source resulting in subsequent prolonged propagation through person-to-person transmission in the community. This capacity for a common-source outbreak to continue propagation through secondary person-to-person spread has been reported with Shigella and Cryptosporidium and may also be a feature of other enteric pathogens having low infectious doses.

An outbreak of norovirus gastroenteritis associated with wedding cakes.

We sought to determine the source of a norovirus outbreak among attendees of 46 weddings taking place during a single weekend. Norovirus-compatible illness was experienced by 332 (39%) of wedding guests surveyed; the outbreak affected up to 2700 persons. Illness was associated with eating wedding cake provided by a bakery common to the weddings (adjusted RR 4.5, P<0.001). A cake requiring direct hand contact during its preparation accounted for the majority of illness. At least two bakery employees experienced norovirus-compatible illness during the week preceding the weddings. Identical sequence types of norovirus were detected in stool specimens submitted by two wedding guests, a wedding hall employee, and one of the ill bakery employees. It is likely that one or more food workers at the bakery contaminated the wedding cakes through direct and indirect contact. These findings reinforce the necessity of proper food-handling practices and of policies that discourage food handlers from working while ill.

An outbreak of primary pneumonic tularemia on Martha's Vineyard.

BACKGROUND: In the summer of 2000, an outbreak of primary pneumonic tularemia occurred on Martha's Vineyard, Massachusetts. The only previously reported outbreak of pneumonic tularemia in the United States also occurred on the island in 1978. METHODS: We conducted a case-control study of adults with pneumonic tularemia and investigated the environment to identify risk factors for primary pneumonic tularemia. Patients with confirmed cases were residents of or visitors to Martha's Vineyard who had symptoms suggestive of primary pneumonic tularemia, were ill between May 15 and October 31, 2000, and had a positive laboratory test for tularemia. Controls were adults who had spent at least 15 days on Martha's Vineyard between May 15 and September 28, 2000. RESULTS: We identified 15 patients with tularemia; 11 of these cases were primary pneumonic tularemia. Francisella tularensis type A was isolated from blood and lung tissue of the one man who died. Patients were more likely than controls to have used a lawn mower or brush cutter in the two weeks before the illness or before an interview, for controls (odds ratio, 9.2; 95 percent confidence interval, 1.6 to 68.0) and during the summer (odds ratio, undefined; 95 percent confidence interval, 1.8 to infinity). Lawn mowing and brush cutting remained significant risk factors after adjustment for other potentially confounding variables. Only one patient reported being exposed to a rabbit while cutting brush. Of 40 trapped animals, 1 striped skunk (Mephitis mephitis) and 1 Norway rat (Rattus norvegicus) were seropositive for antibodies against F. tularensis. CONCLUSIONS: Study of this outbreak of primary pneumonic tularemia implicates lawn mowing and brush cutting as risk factors for this infection.

Use of passive surveillance data to study temporal and spatial variation in the incidence of giardiasis and cryptosporidiosis.

OBJECTIVE: The goal of this study was to evaluate temporal and spatial variations in the reporting of cases of giardiasis and cryptosporidiosis to a passive surveillance system, and to assess the relationship of those variations to source of drinking water, adjusting for socioeconomic variables. METHODS: The authors analyzed temporal and spatial patterns for 4,058 cases of giardiasis and 230 cases of cryptosporidiosis reported to the Massachusetts Department of Public Health for 1993-1996. They linked each reported case to a database containing information on source of residential water supply and socioeconomic characteristics and evaluated the association between these factors and reporting rates using regression techniques. RESULTS: Reports of giardiasis and cryptosporidiosis were highest for the mixed unfiltered drinking water supply category. Reports of giardiasis were associated with income levels. Increases in reporting for both giardiasis and cryptosporidiosis were seen in summer to early fall. During a suspected outbreak of cryptosporidiosis n the city of Worcester in 1995, a significant increase in reported cases was also observed in the Boston metropolitan area. Following the suspected outbreak, weekly giardiasis rates increased slightly in Worcester and the Boston metropolitan area, while reporting of cryptosporidiosis increased dramatically. CONCLUSIONS: Consistently collected passive surveillance data have the potential to provide valuable information on the temporal variation of disease incidence as well as geographic factors. However, passive surveillance data, particularly in the initial period of surveillance, may be highly sensitive to patterns of diagnosis and reporting and should be interpreted with caution.

Immunization registries in the United States: implications for the practice of public health in a changing health care system.

Although immunization rates among children are rising across the country, rates in inner-city areas have remained at approximately 50%-60%, < or = 30% lower than corresponding suburban or state immunization levels. The failure to raise immunization levels in poor, underserved populations is caused in part by the lack of timely and accurate child-specific immunization information for providers and parents. Immunization registries are a new tool in health care that can be used to address these and other barriers to effective immunization delivery. Moreover, immunization registries have the potential to help health care officials track and improve delivery for a broad range of important child health services. An immunization registry is a computerized database of information on children (usually preschool-age children) in a defined population (e.g. those enrolled in a health maintenance organization or living in a specific geographic area), which is used to record and track all immunizations received by each child. The registry receives the information primarily from public and private providers that administer immunizations, as well as from parents, schools, and other agencies. A fully functioning immunization registry can be used to identify individual children in need of immunizations and to report on immunization rates by population characteristics such as child age, assigned provider, or geographic area (e.g. neighborhood, city). Today, > 250 local public health departments have immunization registries that are in various stages of planning or development. Only a small number of these registries meet the minimum functional criteria of maintaining records on 95% of all eligible 2-year-old children in the target population and providing an electronic immunization record that is accessible to providers. Nascent immunization registries represent innovative technologic solutions to the challenge of monitoring health problems and health care access on a population basis. This is a fundamental activity of public health agencies, but one that is increasingly shared by large health maintenance organizations. The study of the development of immunization registries across the United States provides an important case study for how public health agencies will use the rapidly developing health information infrastructure to perform health assessment and health assurance activities in a managed care environment.

Multiple cases of life-threatening adenovirus pneumonia in a mental health care center.

Eighteen cases of pneumonia developed during an outbreak of adenovirus infection in a chronic psychiatric care facility. The six patients most severely affected were admitted to the intensive care unit (ICU) at our institution. Four of these patients developed septic shock. We report the presentation, disease progression, and response to treatment of these patients. Clinical features consisted of high fever, nonproductive cough, and dense lower lobe infiltrates. Laboratory abnormalities included transient fall in white blood cell and platelet counts, and elevations of transaminases, lactate dehydrogenase (LDH), and creatinine phosphokinase (CPK). Five patients were intubated for hypoxemia and four developed the acute respiratory distress syndrome (ARDS) and septic shock (mean cardiac output, 14.1 +/- 1.3 L/min; cardiac index, 6.4 +/- 0.4 L/min/min2; systemic vascular resistance, 326 +/- 107 dyne cm/s2). All patients recovered and were discharged back to the chronic care facility except for one patient with chronic renal failure who died 2 mo after admission. Adenovirus (serotype 35) was isolated from the respiratory secretions of five patients and antibody titers increased 6-fold in the other. These patients constitute the largest series of patients with ARDS and septic shock caused by adenovirus pneumonia and the first outbreak of multiple cases of adenovirus pneumonia in immunocompetent civilian adults occurring from a single source.

Outbreak of adenovirus 35 pneumonia among adult residents and staff of a chronic care psychiatric facility.

Outbreaks of acute respiratory disease caused by adenovirus are rarely documented in civilian populations, and adenovirus 35 is an uncommon serotype best recognized as a cause of serious disease in immunocompromised patients. An outbreak of adenovirus 35 pneumonia among residents and staff of a chronic care psychiatric facility was investigated. Fourteen (26%) of 53 residents and 4 (2%) of approximately 200 staff had radiographically confirmed pneumonia. Thirteen (93%) of 14 residents with pneumonia were hospitalized, 5 (36%) required mechanical ventilation, and 1 (7%) died. One staff member was hospitalized. Adenovirus infection was diagnosed in 17 (94%) persons with pneumonia by culture or serology and was confirmed as adenovirus 35 infection in 8 persons. Residents with pneumonia had resided at the facility longer than other residents. Chronic illness was not a risk factor for severe disease. Crowding and poor hygienic behaviors probably facilitated transmission among residents.

The role of arbitrarily primed PCR in identifying the source of an outbreak of Legionnaires' disease.

An outbreak of community-acquired Legionnaires' disease (LD) occurred in Providence, R.I., in fall 1993. To find the outbreak source, exposures of 17 case patients were compared to those of 33 matched controls. Case patients were more likely than controls to have visited a section of downtown (area A) during the 2 weeks before illness (11 [65%] versus 9 [27%]; matched odds ratio, 6.5; P = 0.01). Water samples were cultured from 27 aerosol-producing devices within area A. Legionella pneumophila serogroup 1 isolates underwent monoclonal antibody (MAb) subtyping and arbitrarily primed PCR (AP-PCR). All four L. pneumophila serogroup 1 isolates available from case patients who visited area A had identical MAb and AP-PCR patterns. Among 14 environmental isolates, 5 had MAb patterns that matched the case patient isolates, but only 1 had a matching AP-PCR pattern. This investigation implicates a cooling tower in area A as the outbreak source and illustrates the usefulness of AP-PCR for identifying sources of LD outbreaks.

Entomologic index for human risk of Lyme disease.

An entomologic index based on density estimates of Lyme disease spirochete-infected nymphal deer ticks (lxodes scapularis) was developed to assess human risk of Lyme disease. The authors used a standardized protocol to determine tick density and infection in numerous forested sites in six Rhode Island towns. An entomologic risk index calculated for each town was compared with the number of human Lyme disease cases reported to the Rhode Island State Health Department for the same year. A strong positive relation between entomologic risk index and the Lyme disease case rate for each town suggested that the entomologic index was predictive of Lyme disease risk.

Reconciling science and policy in setting federal drinking water standards--four states' perspectives.

After almost 20 years of experience with implementing the Safe Drinking Water Act and eight with Amendments to the Act, the individual states within the United States have gained valuable experience while trying to reconcile the legal mandates provided by the statutes with the science underlying them. This paper presents four different topics illustrating the problems of reconciling these two issues in the regulation of toxic chemicals in drinking waters. It presents these from the perspectives of the states of Massachusetts, Rhode Island, Connecticut, and New Jersey and offers suggestions for improved program efficiency based on considerations of comparative human health risks. The approach and schedule for controlling toxic chemicals used through 1994 are first examined and a recommendation is made for more flexibility in the rate at which chemicals are regulated. Recent U.S. EPA proposals to more stringently control radon in drinking waters are presented in the context of all sources of radon exposures, illustrating the intersection of science, laws, and economic consequences of regulatory initiatives. Inhalation and dermal exposures as a result of using chemically contaminated drinking waters are then discussed with the suggestion of the possible underprotectiveness of some present standards. Finally, the difficulty faced by the states and federal government in the control of naturally occurring arsenic exposures through drinking water is also presented and an argument is made for more local flexibility in the application of health-based standards.