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Cluster 5 picocyanobacteria significantly contribute to primary productivity in aquatic ecosystems. Estuarine populations are highly diverse and consist of many co-occurring strains, but their physiology remains largely understudied. In this study, we characterized 17 novel estuarine picocyanobacterial strains. Phylogenetic analysis of the 16S rRNA and pigment genes (cpcB and cpeBA) uncovered multiple estuarine and freshwater-related clusters and pigment types. Assays with five representative strains (three phycocyanin rich and two phycoerythrin rich) under temperature (10–30°C), light (10–190 μmol photons m−2 s−1), and salinity (2–14 PSU) gradients revealed distinct growth optima and tolerance, indicating that genetic variability was accompanied by physiological diversity. Adaptability to environmental conditions was associated with differential pigment content and photosynthetic performance. Amplicon sequence variants at a coastal and an offshore station linked population dynamics with phylogenetic clusters, supporting that strains isolated in this study represent key ecotypes within the Baltic Sea picocyanobacterial community. The functional diversity found within strains with the same pigment type suggests that understanding estuarine picocyanobacterial ecology requires analysis beyond the phycocyanin and phycoerythrin divide. This new knowledge of the environmental preferences in estuarine picocyanobacteria is important for understanding and evaluating productivity in current and future ecosystems.

The first outbreak of avian influenza A (H5N1) occurred among humans in Hong Kong in 1997. To estimate the risk of person-to-person transmission, a retrospective cohort study was conducted to compare the prevalence of H5N1 antibody among health care workers (HCWs) exposed to H5N1 case-patients with the prevalence among nonexposed HCWs. Information on H5N1 case-patient and poultry exposures and blood samples for H5N1-specific antibody testing were collected. Eight (3.7%) of 217 exposed and 2 (0.7%) of 309 nonexposed HCWs were H5N1 seropositive (P=.01). The difference remained significant after controlling for poultry exposure (P=.01). This study presents the first epidemiologic evidence that H5N1 viruses were transmitted from patients to HCWs. Human-to-human transmission of avian influenza may increase the chances for the emergence of a novel influenza virus with pandemic potential.

The first documented outbreak of human respiratory disease caused by avian influenza A (H5N1) viruses occurred in Hong Kong in 1997. The kinetics of the antibody response to the avian virus in H5N1-infected persons was similar to that of a primary response to human influenza A viruses; serum neutralizing antibody was detected, in general, >/=14 days after symptom onset. Cohort studies were conducted to assess the risk of human-to-human transmission of the virus. By use of a combination of serologic assays, 6 of 51 household contacts, 1 of 26 tour group members, and none of 47 coworkers exposed to H5N1-infected persons were positive for H5 antibody. One H5 antibody-positive household contact, with no history of poultry exposure, provided evidence that human-to-human transmission of the avian virus may have occurred through close physical contact with H5N1-infected patients. In contrast, social exposure to case patients was not associated with H5N1 infection.

We conducted prospective, active population-based surveillance for candidemia (defined as any Candida species isolated from blood) in Atlanta and San Francisco (total population, 5.34 million) during 1992‐1993. The average annual incidence of candidemia at both sites was 8 per 100,000 population. The highest incidence (75 per 100,000) occurred among infants

To determine the incidence of cryptococcosis and its risk factors among human immunodeficiency virus (HIV)-infected persons, population-based active surveillance was conducted in four US areas (population, 12.5 million) during 1992-1994, and a case-control study was done. Of 1083 cases, 931 (86%) occurred in HIV-infected persons. The annual incidence of cryptococcosis per 1000 among persons living with AIDS ranged from 17 (San Francisco, 1994) to 66 (Atlanta, 1992) and decreased significantly in these cities during 1992-1994. Among non-HIV-infected persons, the annual incidence of cryptococcosis ranged from 0.2 to 0.9/ 100,000. Multivariate analysis of the case-control study (158 cases and 423 controls) revealed smoking and outdoor occupations to be significantly associated with an increased risk of cryptococcosis; receiving fluconazole within 3 months before enrollment was associated with a decreased risk for cryptococcosis. Further studies are needed to better describe persons with AIDS currently developing cryptococcosis in the era of highly active antiretroviral therapy.

Acute infectious disease presentations among many at-risk patient groups (eg, uninsured, homeless, and recent immigrants) are frequently seen in emergency departments. Therefore EDs may be useful sentinel sites for infectious disease surveillance. This article describes the background, development, and implementation of EMERGE ncy ID NET, an interdisciplinary, multicenter, ED-based network for research of emerging infectious diseases. EMERGE ncy ID NET was established in cooperation with the National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC) as part of the CDC's strategy to expand and complement existing disease detection and control activities. The network is based at 11 university-affiliated, urban hospital EDs with a combined annual patient visit census of more than 900,000. Data are collected during ED evaluation of patients with specific clinical syndromes, and are electronically stored, transferred, and analyzed at a central receiving site. Current projects include investigation of bloody diarrhea and the prevalence of Shiga toxin-producing Escherichia coli, animal exposures and rabies postexposure prophylaxis practices, seizures and prevalence of neurocysticercosis, nosocomial ED Mycobacterium tuberculosis transmission, and hospital isolation bed use for adults admitted for pneumonia or suspected tuberculosis. EMERGE ncy ID NET also was developed to be a mechanism for rapidly responding to new diseases or epidemics. Future plans include study of antimicrobial use, meningitis, and encephalitis, and consideration of other public health concerns such as injury and national and international network expansion.

The growing automation of healthcare information affects surveillance systems that depend on information arising from healthcare use. Changing communications technologies and styles affect population health surveys. CDC's Public Health Surveillance & Informatics Program Office (PHSIPO) manages the National Notifiable Diseases Surveillance System, BioSense 2.0, and the Behavioral Risk Factor Surveillance System (BRFSS) and serves as the 'home' at CDC for addressing cross-cutting issues in surveillance and informatics practice. This panel will discuss how PHSIPO is supporting health departments in adapting to the changing public health landscape and will provide opportunities to hear from audience members.

The Public Health Information Network (PHIN) Preparedness initiative strives to implement, on an accelerated pace, a consistent national network of information systems that will support public health in being prepared for public health emergencies. Using the principles and practices of the broader PHIN initiative, PHIN Preparedness concentrates in the short term on ensuring that all public health jurisdictions have, or have access to, systems to accomplish known preparedness functions. The PHIN Preparedness initiative defines functional requirements, technical standards and specifications, and a process to achieve consistency and interconnectedness of preparedness systems across public health.

In 1997, outbreaks of highly pathogenic influenza A (H5N1) among poultry coincided with 18 documented human cases of H5N1 illness. Although exposure to live poultry was associated with human illness, no cases were documented among poultry workers (PWs). To evaluate the potential for avian-to-human transmission of H5N1, a cohort study was conducted among 293 Hong Kong government workers (GWs) who participated in a poultry culling operation and among 1525 PWs. Paired serum samples collected from GWs and single serum samples collected from PWs were considered to be anti-H5 antibody positive if they were positive by both microneutralization and Western blot testing. Among GWs, 3% were seropositive, and 1 seroconversion was documented. Among PWs, approximately 10% had anti-H5 antibody. More-intensive poultry exposure, such as butchering and exposure to ill poultry, was associated with having anti-H5 antibody. These findings suggest an increased risk for avian influenza infection from occupational exposure.

To determine national trends in mortality due to invasive mycoses, we analyzed National Center for Health Statistics multiple-cause-of-death record tapes for the years 1980 through 1997, with use of their specific codes in the International Classification of Diseases, Ninth Revision (ICD-9 codes 112.4-118 and 136.3). In the United States, of deaths in which an infectious disease was the underlying cause, those due to mycoses increased from the tenth most common in 1980 to the seventh most common in 1997. From 1980 through 1997, the annual number of deaths in which an invasive mycosis was listed on the death certificate (multiple-cause [MC] mortality) increased from 1557 to 6534. In addition, rates of MC mortality for the different mycoses varied markedly according to human immunodeficiency virus (HIV) status but were consistently higher among males, blacks, and personsor =65 years of age. These data highlight the public health importance of mycotic diseases and emphasize the need for continuing surveillance.

Background: A recent study concluded that between 1980 and 1992, deaths from infectious diseases increased 58%. This article explores trends in infectious diseases as a cause of hospitalization. Methods: We analyzed data from the National Hospitalization Discharge Survey for 1980 through 1994 using a previously developed approach to evaluate infectious diseases in data coded according to the International Classification of Diseases, Ninth Revision. Results: Between 1980 and 1994, the rate of hospitalizations in the United States declined approximately 33%; hospitalizations occurred at a rate of 133 ± 5 per 1000 US population (35 million ± 1 million discharges) in 1994. The rate of hospitalization for infectious diseases declined less steeply—12% during this interval—resulting in an increased proportion of hospitalizations because of infectious diseases. In 1994, the rate of hospitalizations for infectious diseases was 15.4 ± 0.7 per 1000 US population (4.0 million ± 0.2 million discharges). The fatality rate associated with hospitalizations for infectious diseases increased from 1.9% ± 0.1% to 4.0% ± 0.3%, attributable to increased hospitalizations of elderly persons and an increased fatality rate among those younger than 65 years. Among selected categories, hospitalizations for human immunodeficiency virus infections and acquired immunodeficiency syndrome, prosthetic device infections, sepsis, and mycosis increased substantially, and hospitalizations for upper respiratory tract infections, pelvic inflammatory disease, and oral infections declined sharply. Hospitalizations for lower respiratory tract infections constituted 37% of all infectious disease hospitalizations in 1994. Conclusions: Considering hospitalizations as a dimension of the burden of infectious diseases involves an array of factors: secular trends in hospitalization, changing case management practices, demographic changes, and trends in the variety of infectious diseases themselves. Increases in the proportions of hospitalizations because of infectious diseases during years when hospitalizations for all causes were decreasing reflect an increasing burden of infectious diseases in the United States between 1989 and the mid-1990s. Arch Intern Med. 1998;158:1923-1928

PURPOSE: Although cryptococcosis is a significant opportunistic infection among patients with human immunodeficiency virus (HIV), there is conflicting information on rates of cryptococcosis among HIV-positive and HIV-negative patients. Precise state-wide epidemiologic data for cryptococcosis are not available in Alabama. METHODS: We conducted an active laboratory and hospital medical record-based surveillance for cryptococcosis in Alabama from October 1, 1992 to September 30, 1994. A case of cryptococcosis was defined as a patient's initial episode of cryptococcal disease and based on either a positive culture for C. neoformans from any normally sterile site, a positive latex agglutination serologic test for cryptococcal antigen in CSF or serum, or histopathologic findings consistent with C. neoformans . RESULTS: Over the two year period, 153 cases were identified. The diagnosis was based on positive culture (37%), positive antigen (24%), positive autopsy culture (2%), and histopathologic findings (4%). Further, 33% of the total cases were diagnosed from combined positive culture, antigen, or histopathology. Of the total 153 cases, 55% were in HIV-positive patients and 44% were in HIV-negative individuals and one case (1%) had an unknown HIV status. The overall annual incidence rate of cryptococcosis was 1.89 cases per 100,000 population. The incidence was 1638.7 per 100,000 in the HIV-positive population and 0.84 per 100,000 in the HIV-negative population. CONCLUSION: The first Alabama statewide active surveillance system for cryptococcosis confirms previous observations that rates of cryptococcosis are consistently higher in HIV-infected individuals than in their HIV-negative counterparts. In Alabama, cryptococcosis occurs more commonly in urban residents and in men. Cryptococcosis in HIV-positive persons is more likely to occur in the 20 to 44 year age group, whereas cryptococcosis in HIV-negative persons is more likely to occur in those greater than 45 years old.

Context Recent increases in infectious disease mortality and concern about emerging infections warrant an examination of longer-term trends. Objective To describe trends in infectious disease mortality in the United States during the 20th century. Design and setting Descriptive study of infectious disease mortality in the United States. Deaths due to infectious diseases from 1900 to 1996 were tallied by using mortality tables. Trends in age-specific infectious disease mortality were examined by using age-specific death rates for 9 common infectious causes of death. Subjects Persons who died in the United States between 1900 and 1996. Main outcome measures Crude and age-adjusted mortality rates. Results Infectious disease mortality declined during the first 8 decades of the 20th century from 797 deaths per 100000 in 1900 to 36 deaths per 100000 in 1980. From 1981 to 1995, the mortality rate increased to a peak of 63 deaths per 100000 in 1995 and declined to 59 deaths per 100000 in 1996. The decline was interrupted by a sharp spike in mortality caused by the 1918 influenza epidemic. From 1938 to 1952, the decline was particularly rapid, with mortality decreasing 8.2% per year. Pneumonia and influenza were responsible for the largest number of infectious disease deaths throughout the century. Tuberculosis caused almost as many deaths as pneumonia and influenza early in the century, but tuberculosis mortality dropped off sharply after 1945. Infectious disease mortality increased in the 1980s and early 1990s in persons aged 25 years and older and was mainly due to the emergence of the acquired immunodeficiency syndrome (AIDS) in 25- to 64-year-olds and, to a lesser degree, to increases in pneumonia and influenza deaths among persons aged 65 years and older. There was considerable year-to-year variability in infectious disease mortality, especially for the youngest and oldest age groups. Conclusions Although most of the 20th century has been marked by declining infectious disease mortality, substantial year-to-year variation as well as recent increases emphasize the dynamic nature of infectious diseases and the need for preparedness to address them.

Acute infectious disease presentations among many at-risk patient groups (eg, uninsured, homeless, and recent immigrants) are frequently seen in emergency departments. Therefore EDs may be useful sentinel sites for infectious disease surveillance. This article describes the background, development, and implementation of EMERGE ncy ID NET, an interdisciplinary, multicenter, ED-based network for research of emerging infectious diseases. EMERGE ncy ID NET was established in cooperation with the National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC) as part of the CDC's strategy to expand and complement existing disease detection and control activities. The network is based at 11 university-affiliated, urban hospital EDs with a combined annual patient visit census of more than 900,000. Data are collected during ED evaluation of patients with specific clinical syndromes, and are electronically stored, transferred, and analyzed at a central receiving site. Current projects include investigation of bloody diarrhea and the prevalence of Shiga toxin-producing Escherichia coli, animal exposures and rabies postexposure prophylaxis practices, seizures and prevalence of neurocysticercosis, nosocomial ED Mycobacterium tuberculosis transmission, and hospital isolation bed use for adults admitted for pneumonia or suspected tuberculosis. EMERGE ncy ID NET also was developed to be a mechanism for rapidly responding to new diseases or epidemics. Future plans include study of antimicrobial use, meningitis, and encephalitis, and consideration of other public health concerns such as injury and national and international network expansion.