Showing papers by "Centers for Disease Control and Prevention published in 2000"

Meta-analysis of observational studies in epidemiology - A proposal for reporting

Abstract: ObjectiveBecause of the pressure for timely, informed decisions in public health and clinical practice and the explosion of information in the scientific literature, research results must be synthesized. Meta-analyses are increasingly used to address this problem, and they often evaluate observational studies. A workshop was held in Atlanta, Ga, in April 1997, to examine the reporting of meta-analyses of observational studies and to make recommendations to aid authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based on expertise in clinical practice, trials, statistics, epidemiology, social sciences, and biomedical editing. Deliberations of the workshop were open to other interested scientists. Funding for this activity was provided by the Centers for Disease Control and Prevention.EvidenceWe conducted a systematic review of the published literature on the conduct and reporting of meta-analyses in observational studies using MEDLINE, Educational Research Information Center (ERIC), PsycLIT, and the Current Index to Statistics. We also examined reference lists of the 32 studies retrieved and contacted experts in the field. Participants were assigned to small-group discussions on the subjects of bias, searching and abstracting, heterogeneity, study categorization, and statistical methods.Consensus ProcessFrom the material presented at the workshop, the authors developed a checklist summarizing recommendations for reporting meta-analyses of observational studies. The checklist and supporting evidence were circulated to all conference attendees and additional experts. All suggestions for revisions were addressed.ConclusionsThe proposed checklist contains specifications for reporting of meta-analyses of observational studies in epidemiology, including background, search strategy, methods, results, discussion, and conclusion. Use of the checklist should improve the usefulness of meta-analyses for authors, reviewers, editors, readers, and decision makers. An evaluation plan is suggested and research areas are explored.

Practice Guidelines for the Management of Community-Acquired Pneumonia in Adults

Abstract: John G. Bartlett,1 Scott F Dowell,2 Lionel A. Mandell,6 Thomas M. File, Jr.,3 Daniel M. Musher,4 and Michael J. Fine5 'Johns Hopkins University School of Medicine, Baltimore, Maryland, 2Centers for Disease Control and Prevention, Atlanta, Georgia, 3Northeastern Ohio Universities College of Medicine, Cleveland, Ohio, 4Baylor College of Medicine and Veterans Affairs Medical Center, Houston, Texas, and 5University of Pittsburgh, Pennsylvania, USA; and 6McMaster University, Toronto, Canada

Levels of racism: A theoretic framework and a gardener's tale.

Abstract: The author presents a theoretic framework for understanding racism on 3 levels: institutionalized, personally mediated, and internalized. This framework is useful for raising new hypotheses about the basis of race-associated differences in health outcomes, as well as for designing effective interventions to eliminate those differences. She then presents an allegory about a gardener with 2 flower boxes, rich and poor soil, and red and pink flowers. This allegory illustrates the relationship between the 3 levels of racism and may guide our thinking about how to intervene to mitigate the impacts of racism on health. It may also serve as a tool for starting a national conversation on racism.

Pattern recognition receptors TLR4 and CD14 mediate response to respiratory syncytial virus.

Abstract: The innate immune system contributes to the earliest phase of the host defense against foreign organisms and has both soluble and cellular pattern recognition receptors for microbial products. Two important members of this receptor group, CD14 and the Toll-like receptor (TLR) pattern recognition receptors, are essential for the innate immune response to components of Gram-negative and Gram-positive bacteria, mycobacteria, spirochetes and yeast. We now find that these receptors function in an antiviral response as well. The innate immune response to the fusion protein of an important respiratory pathogen of humans, respiratory syncytial virus (RSV), was mediated by TLR4 and CD14. RSV persisted longer in the lungs of infected TLR4-deficient mice compared to normal mice. Thus, a common receptor activation pathway can initiate innate immune responses to both bacterial and viral pathogens.

National Hospital Discharge Survey

Abstract: Objectives This report presents national estimates of the use of non-Federal short-stay hospitals in the United States during 1995. Estimates are provided by demographic characteristics of patients discharged, geographic region of hospitals, conditions diagnosed, and surgical and nonsurgical procedures performed. Measurements of hospital use include number and rate of discharges and days of care, and the average length of stay. Methods The estimates are based on data collected through the National Hospital Discharge Survey for 1995. In 1995 data were collected for approximately 263,000 discharges. Of the 508 eligible non-Federal short-stay hospitals, 466 (92 percent) responded to the survey. Diagnoses and procedures are presented according to their code numbers listed in the International Classification of Diseases, 9th Revision, Clinical Modification, or ICD-9-CM. Results In 1995 there were an estimated 30.7 million discharges from non-Federal short-stay hospitals. These patients used a total of 164.6 million days of care and had an average length of stay of 5.4 days. Other data summarized in this report include estimates for diagnoses, procedures, expected source of payment, hospital deaths, and newborn infants.

AIDS as a Zoonosis: Scientific and Public Health Implications

Abstract: Evidence of simian immunodeficiency virus (SIV) infection has been reported for 26 different species of African nonhuman primates. Two of these viruses, SIVcpz from chimpanzees and SIVsm from sooty mangabeys, are the cause of acquired immunodeficiency syndrome (AIDS) in humans. Together, they have been transmitted to humans on at least seven occasions. The implications of human infection by a diverse set of SIVs and of exposure to a plethora of additional human immunodeficiency virus—related viruses are discussed.

Prevention of mother-to-child HIV transmission in resource-poor countries: translating research into policy and practice.

Abstract: Each year, an estimated 590,000 infants acquire human immunodeficiency virus type 1 (HIV) infection from their mothers, mostly in developing countries that are unable to implement interventions now standard in the industrialized world. In resource-poor settings, the HIV pandemic has eroded hard-won gains in infant and child survival. Recent clinical trial results from international settings suggest that short-course antiretroviral regimens could significantly reduce perinatal HIV transmission worldwide if research findings could be translated into practice. This article reviews current knowledge of mother-to-child HIV transmission in developing countries, summarizes key findings from the trials, outlines future research requirements, and describes public health challenges of implementing perinatal HIV prevention interventions in resource-poor settings. Public health efforts must also emphasize primary prevention strategies to reduce incident HIV infections among adolescents and women of childbearing age. Successful implementation of available perinatal HIV interventions could substantially improve global child survival.

Changes in physical activity patterns in the United States, by sex and cross-sectional age

Abstract: CASPERSEN, C. J., M. A. PEREIRA, and K. M. CURRAN. Changes in physical activity patterns in the United States, by sex and cross-sectional age. Med. Sci. Sports Exerc., Vol. 32, No. 9, pp. 1601‐1609, 2000. Purpose: To determine sex-specific, age-related changes in physical activity patterns. Methods: We examined cross-sectional data from the National Health Interview Survey, using the 1992 Youth Risk Behavior Survey supplement for adolescents and the 1991 Health Promotion/Disease Prevention supplement for adults. Physical activity patterns were modeled after Healthy People 2000 objectives. Results: Among adolescents, physical activity patterns generally eroded most from ages 15 through 18. The “regular, vigorous activity” and strengthening patterns declined consistently from ages 12 through 21. Young adulthood (18 ‐29 yr) often marked continuing erosion of activity patterns, whereas middle adulthood (30 ‐ 64 yr) often revealed relatively stable patterns. At retirement age (65 yr), there was a stabilizing, or even an improving, tendency in activity patterns, usually followed by further erosion through the final period of life. Strengthening behavior eroded dramatically with advancing age among adults, especially among men. Among adolescents, differences between female and male respondents were large for regular, vigorous activity (11.3 percentage points greater for male respondents). In comparison with female adolescents and adults, male respondents reported much higher rates of regular, sustained activity (5.5 and 5.9 percentage points, respectively), and strengthening (18.2 and 11.3 percentage points, respectively). Among adults, levels of physical inactivity among women were moderately greater (5.5 percentage points) than for men. Absolute rates of change per year were mostly large to very large (3.0 ‐ 8.0 percentage pointszyr 21 ) during ages 15‐18 yr, but, for adults, they were small (,0.5 percentage pointszyr 21 ) for 33 of 40 sex,

Nipah Virus: A Recently Emergent Deadly Paramyxovirus

Abstract: A paramyxovirus virus termed Nipah virus has been identified as the etiologic agent of an outbreak of severe encephalitis in people with close contact exposure to pigs in Malaysia and Singapore. The outbreak was first noted in late September 1998 and by mid-June 1999, more than 265 encephalitis cases, including 105 deaths, had been reported in Malaysia, and 11 cases of encephalitis or respiratory illness with one death had been reported in Singapore. Electron microscopic, serologic, and genetic studies indicate that this virus belongs to the family Paramyxoviridae and is most closely related to the recently discovered Hendra virus. We suggest that these two viruses are representative of a new genus within the family Paramyxoviridae. Like Hendra virus, Nipah virus is unusual among the paramyxoviruses in its ability to infect and cause potentially fatal disease in a number of host species, including humans.

Screening for type 2 diabetes.

Abstract: Definitive studies of the effectiveness of screening for type 2 diabetes are currently not available. RCTs would be the best means to assess effectiveness, but several barriers prevent these studies from being conducted. Prospective observational studies may characterize some of the benefits of screening by creating screened and unscreened groups for comparison. The availability of better data systems and health services research techniques will facilitate such comparisons. Unfortunately, the interpretation of the results of such studies is extremely problematic. Several screening tests have been evaluated. Risk assessment questionnaires have generally performed poorly as stand-alone tests. Screening with biochemical tests performs better. Venous and capillary glucose measurements may perform more favorably than urinary glucose or HbA(1c) measurements, and measuring postprandial glucose levels may have advantages over measuring fasting levels. However, performance of all screening tests is dependent on the cutoff point selected. Unfortunately, there are no well-defined and validated cutoff points to define positive tests. A two-stage screening test strategy may assist with a more efficient use of resources, although such approaches have not been rigorously tested. The optimal interval for screening is unknown. Even though periodic, targeted, and opportunistic screening within the existing health care system seems to offer the greatest yield and likelihood of appropriate follow-up and treatment, much of the reported experience with screening appears to be episodic poorly targeted community screening outside of the existing health care system. Statistical models have helped to answer some of the key questions concerning areas in which there is lack of empirical data. Current models need to be refined with new clinical and epidemiological information, such as the UKPDS results (200). In addition, future models need to include better information on the natural history of the preclinical phase of diabetes. Data from ongoing clinical trials of screening and treatment of impaired glucose tolerance, such as the Diabetes Prevention Program, may eventually offer more direct evidence for early detection and treatment of asymptomatic hyperglycemia (201). It will be important to use comprehensive cardiovascular disease modules that assess the conjoint influence of glucose and cardiovascular risk factor reduction, information on QOL, and refined economic evaluations using common outcome measures (cost per life-year or QALY gained) (11,178,202-204). Such studies should consider all of the costs associated with a comprehensive screening program, including, at a minimum, the direct costs of screening, diagnostic testing, and care for patients with diabetes detected through screening. Finally, combinations of screening tests and different screening intervals should be evaluated within economic studies to allow selection of the optimal approach within the financial and resource limitations of the health care system.

5, 10-Methylenetetrahydrofolate Reductase Gene Variants and Congenital Anomalies: A HuGE Review

Abstract: The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism. The MTHFR gene is located on chromosome 1 (1p36.3), and two common alleles, the C677T (thermolabile) allele and the A1298C allele, have been described. The population frequency of C677T homozygosity ranges from 1% or less among Blacks from Africa and the United States to 20% or more among Italians and US Hispanics. C677T homozygosity in infants is associated with a moderately increased risk for spina bifida (pooled odds ratio = 1.8; 95% confidence interval: 1.4, 2.2). Maternal C677T homozygosity also appears to be a moderate risk factor (pooled odds ratio = 2.0; 95% confidence interval: 1.5, 2.8). The A 1298C allele combined with the C677T allele also could be associated with an increased risk for spina bifida. Some data suggest that the risk for spina bifida associated with C677T homozygosity may depend on nutritional status (e.g., blood folate levels, intake of vitamins) or on the genotype of other folate-related genes (e.g., cystathionine-beta-synthase and methionine synthase reductase). Studies of the C677T allele in relation to oral clefts, Down syndrome, and fetal anticonvulsant syndrome either have yielded conflicting results or have not been yet replicated.

Diabetes trends in the U.S.: 1990-1998.

Abstract: OBJECTIVE: To examine trends in diabetes prevalence in the U.S. RESEARCH DESIGN AND METHODS: This study was conducted via telephone surveys in states that participated in the Behavioral Risk Factor Surveillance System between 1990 and 1998. The participants consisted of noninstitutionalized adults aged 18 years or older. The main outcome measure was self-reported diabetes. RESULTS: The prevalence of diabetes rose from 4.9% in 1990 to 6.5% in 1998--an increase of 33%. Increases were observed in both sexes, all ages, all ethnic groups, all education levels, and nearly all states. Changes in prevalence varied by state. The prevalence of diabetes was highly correlated with the prevalence of obesity (r = 0.64, P

Rapid Detection of West Nile Virus from Human Clinical Specimens, Field-Collected Mosquitoes, and Avian Samples by a TaqMan Reverse Transcriptase-PCR Assay

Abstract: The authors report on the development and application of a rapid TaqMan assay for the detection of West Nile (WN) virus in a variety of human clinical specimens and field-collected specimens. Oligonucleotide primers and FAM- and TAMRA-labeled WN virus-specific probes were designed by using the nucleotide sequence of the New York 1999 WN virus isolate. The TaqMan assay was compared to a traditional reverse transcriptase (RT)-PCR assay and to virus isolation in Vero cells with a large number ( approximately 500) of specimens obtained from humans (serum, cerebrospinal fluid, and brain tissue), field-collected mosquitoes, and avian tissue samples. The TaqMan assay was specific for WN virus and demonstrated a greater sensitivity than the traditional RT-PCR method and correctly identified WN virus in 100% of the culture-positive mosquito pools and 98% of the culture-positive avian tissue samples. The assay should be of utility in the diagnostic laboratory to complement existing human diagnostic testing and as a tool to conduct WN virus surveillance in the United States.

Influenza and the rates of hospitalization for respiratory disease among infants and young children.

Abstract: Background Young children may be at increased risk for serious complications from influenzavirus infection. However, in population-based studies it has been difficult to separate the effects of influenzavirus from those of respiratory syncytial virus. Respiratory syncytial virus often circulates with influenzaviruses and is the most frequent cause of hospitalization for lower respiratory tract infections in infants and young children. We studied the rates of hospitalization for acute respiratory disease among infants and children during periods when the circulation of influenzaviruses predominated over the circulation of respiratory syncytial virus. Methods For each season from October to May during the period from 1992 to 1997, we used local viral surveillance data to define periods in Washington State and northern California when the circulation of influenzaviruses predominated over that of respiratory syncytial virus. We calculated the rates of hospitalization for acute respiratory disease, excess rate...

Epidemiology of hepatitis C: geographic differences and temporal trends.

Abstract: Hepatitis C Virus (HCV) infection appears to be endemic in most parts of the world, with an estimated overall prevalence of 3%. However, there is considerable geographic and temporal variation in the incidence and prevalence of HCV infection. Using age-specific prevalence data, at least three distinct transmission patterns can be identified. In countries with the first pattern (e.g., United States, Australia), most infections are found among persons 30-49 years old, indicating that the risk for HCV infection was greatest in the relatively recent past (10-30 years ago) and primarily affected young adults. In countries with the second pattern (e.g., Japan, Italy), most infections are found among older persons, consistent with the risk for HCV infection having been greatest in the distant past. In countries with the third pattern (e.g., Egypt), high rates of infection are observed in all age groups, indicating an ongoing high risk for acquiring HCV infection. In countries with the first pattern, injection drug use has been the predominant risk factor for HCV infection, whereas in those with the second or third patterns, unsafe injections and contaminated equipment used in healthcare-related procedures appear to have played a predominant role in transmission. Much of the variability between regions can be explained by the frequency and extent to which different risk factors have contributed to the transmission of HCV. Because different strategies are required to interrupt different patterns of HCV transmission, determining the epidemiology of HCV infection in areas where that information has not yet been assessed is critical for developing appropriate prevention programs.

HIV-1 Nomenclature Proposal

Abstract: A clear and consistent genetic classification of human immunodeficiency virus-type 1 (HIV-1) strains continues to be of great utility in epidemiological tracking of the AIDS pandemic and in vaccine design. It also provides a foundation for detecting any biological differences that may have evolved

Nosocomial infections in combined medical-surgical intensive care units in The United States

Abstract: Objective: To describe the epidemiology of nosocomial infections in combined medical-surgical (MS) intensive care units (ICUs) participating in the National Nosocomial Infection Surveillance (NNIS) System. Design: Analysis of surveillance data on 498,998 patients with 1,554,070 patient-days, collected between 1992 and 1998 from 205 MS ICUs following the NNIS Intensive Care Unit protocol, representing 152 participating NNIS hospitals in the United States. Results: Infections at three major sites represented 68% of all reported infections (nosocomial pneumonia, 31%; urinary tract infections (UTIs), 23%; and primary bloodstream infections (BSIs), 14%: 83% of episodes of nosocomial pneumonia were associated with mechanical ventilation, 97% of UTIs occurred in catheterized patients, and 87% of primary BSIs in patients with a central line. In patients with primary BSIs, coagulase-negative staphylococci (39%) were the most common pathogens reported; Staphylococcus aureus (12%) was as frequently reported as enterococci (11%). Coagulase-negative staphylococcal BSIs were increasingly reported over the 6 years, but no increase was seen in candidemia or enterococcal bacteremia. In patients with pneumonia, S aureus (17%) was the most frequently reported isolate. Of reported isolates, 59% were gram-negative bacilli. In patients with UTIs, Escherichia coli (19%) was the most frequently reported isolate. Of reported isolates, 31% were fungi. In patients with surgical-site infections, Enterococcus (17%) was the single most frequently reported pathogen. Device-associated nosocomial infection rates for BSIs, pneumonia, and UTIs did not correlate with length of ICU stay, hospital bed size, number of beds in die ICU, or season. Combined MS ICUs in major teaching hospitals had higher device-associated infection rates compared to all other hospitals with combined medical-surgical units. Conclusions: Nosocomial infections in MS ICUs at the most frequent infection sites (bloodstream, urinary, and respiratory tract) almost always were associated with use of an invasive device. Device-associated infection rates were die best available comparative rates between combined MS ICUs, but the distribution of device-associated rates should be stratified by a hospital's major teaching affiliation status.

Group B Streptococcal Disease in the Era of Intrapartum Antibiotic Prophylaxis

Abstract: Background Group B streptococcal infections are a leading cause of neonatal mortality, and they also affect pregnant women and the elderly. Many cases of the disease in newborns can be prevented by the administration of prophylactic intrapartum antibiotics. In the 1990s, prevention efforts increased. In 1996, consensus guidelines recommended use of either a risk-based or a screening-based approach to identify candidates for intrapartum antibiotics. To assess the effects of the preventive efforts, we analyzed trends in the incidence of group B streptococcal disease from 1993 to 1998. Methods Active, population-based surveillance was conducted in selected counties of eight states. A case was defined by the isolation of group B streptococci from a normally sterile site. Census and live-birth data were used to calculate the race-specific incidence of disease; national projections were adjusted for race. Results Disease in infants less than seven days old accounted for 20 percent of all 7867 group B streptococcal infections. The incidence of early-onset neonatal infections decreased by 65 percent, from 1.7 per 1000 live births in 1993 to 0.6 per 1000 in 1998. The excess incidence of early-onset disease in black infants, as compared with white infants, decreased by 75 percent. Projecting our findings to the entire United States, we estimate that 3900 early-onset infections and 200 neonatal deaths were prevented in 1998 by the use of intrapartum antibiotics. Among pregnant girls and women, the incidence of invasive group B streptococcal disease declined by 21 percent. The incidence among nonpregnant adults did not decline. Conclusions Over a six-year period, there has been a substantial decline in the incidence of group B streptococcal disease in newborns, including a major reduction in the excess incidence of these infections in black infants. These improvements coincide with the efforts to prevent perinatal disease by the wider use of prophylactic intrapartum antibiotics.

Plague as a biological weapon. Medical and public health management.

Abstract: ObjectiveThe Working Group on Civilian Biodefense has developed consensus-based recommendations for measures to be taken by medical and public health professionals following the use of plague as a biological weapon against a civilian population.ParticipantsThe working group included 25 representatives from major academic medical centers and research, government, military, public health, and emergency management institutions and agencies.EvidenceMEDLINE databases were searched from January 1966 to June 1998 for the Medical Subject Headings plague, Yersinia pestis, biological weapon, biological terrorism, biological warfare, and biowarfare. Review of the bibliographies of the references identified by this search led to subsequent identification of relevant references published prior to 1966. In addition, participants identified other unpublished references and sources. Additional MEDLINE searches were conducted through January 2000.Consensus ProcessThe first draft of the consensus statement was a synthesis of information obtained in the formal evidence-gathering process. The working group was convened to review drafts of the document in October 1998 and May 1999. The final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members.ConclusionsAn aerosolized plague weapon could cause fever, cough, chest pain, and hemoptysis with signs consistent with severe pneumonia 1 to 6 days after exposure. Rapid evolution of disease would occur in the 2 to 4 days after symptom onset and would lead to septic shock with high mortality without early treatment. Early treatment and prophylaxis with streptomycin or gentamicin or the tetracycline or fluoroquinolone classes of antimicrobials would be advised.

Increasing prevalence of multidrug-resistant Streptococcus pneumoniae in the United States.

Abstract: Background The emergence of drug-resistant strains of bacteria has complicated treatment decisions and may lead to treatment failures. Methods We examined data on invasive pneumococcal disease in patients identified from 1995 to 1998 in the Active Bacterial Core Surveillance program of the Centers for Disease Control and Prevention. Pneumococci that had a high level of resistance or had intermediate resistance according to the definitions of the National Committee for Clinical Laboratory Standards were defined as “resistant” for this analysis. Results During 1998, 4013 cases of invasive Streptococcus pneumoniae disease were reported (23 cases per 100,000 population); isolates were available for 3475 (87 percent). Overall, 24 percent of isolates from 1998 were resistant to penicillin. The proportion of isolates that were resistant to penicillin was highest in Georgia (33 percent) and Tennessee (35 percent), in children under five years of age (32 percent, vs. 21 percent for persons five or more years of ag...

Smoking-Attributable Periodontitis in the United States: Findings From NHANES III

Abstract: Background: The principal objectives of this study were to examine the relationship between cigarette smoking and periodontitis and to estimate the proportion of periodontitis in the United States adult population that is attributable to cigarette smoking. Methods: Data were derived from the Third National Health and Nutrition Examination Survey, a nationally representative multipurpose health survey conducted in 1988 to 1994. Participants were interviewed about tobacco use and examined by dentists trained to use standardized clinical criteria. Analysis was limited to dentate persons aged ≥18 years with complete clinical periodontal data and information on tobacco use and important covariates (n = 12,329). Data were weighted to provide U.S. national estimates, and analyses accounted for the complex sample design. We defined periodontitis as the presence of ≥1 site with clinical periodontal attachment level ≥4 mm apical to the cemento-enamel junction and probing depth ≥4 mm. Current cigarette smokers were ...

Trends and Disparities in Coronary Heart Disease, Stroke, and Other Cardiovascular Diseases in the United States Findings of the National Conference on Cardiovascular Disease Prevention

Abstract: A workshop was held September 27 through 29, 1999, to address issues relating to national trends in mortality and morbidity from cardiovascular diseases; the apparent slowing of declines in mortality from cardiovascular diseases; levels and trends in risk factors for cardiovascular diseases; disparities in cardiovascular diseases by race/ethnicity, socioeconomic status, and geography; trends in cardiovascular disease preventive and treatment services; and strategies for efforts to reduce cardiovascular diseases overall and to reduce disparities among subpopulations. The conference concluded that coronary heart disease mortality is still declining in the United States as a whole, although perhaps at a slower rate than in the 1980s; that stroke mortality rates have declined little, if at all, since 1990; and that there are striking differences in cardiovascular death rates by race/ethnicity, socioeconomic status, and geography. Trends in risk factors are consistent with a slowing of the decline in mortality; there has been little recent progress in risk factors such as smoking, physical inactivity, and hypertension control. There are increasing levels of obesity and type 2 diabetes, with major differences among subpopulations. There is considerable activity in population-wide prevention, primary prevention for higher risk people, and secondary prevention, but wide disparities exist among groups on the basis of socioeconomic status and geography, pointing to major gaps in efforts to use available, proven approaches to control cardiovascular diseases. Recommendations for strategies to attain the year 2010 health objectives were made.

Early Alterations of the Receptor-Binding Properties of H1, H2, and H3 Avian Influenza Virus Hemagglutinins after Their Introduction into Mammals

Abstract: Interspecies transmission of influenza A viruses circulating in wild aquatic birds occasionally results in influenza outbreaks in mammals, including humans. To identify early changes in the receptor binding properties of the avian virus hemagglutinin (HA) after interspecies transmission and to determine the amino acid substitutions responsible for these alterations, we studied the HAs of the initial isolates from the human pandemics of 1957 (H2N2) and 1968 (H3N2), the European swine epizootic of 1979 (H1N1), and the seal epizootic of 1992 (H3N3), all of which were caused by the introduction of avian virus HAs into these species. The viruses were assayed for their ability to bind the synthetic sialylglycopolymers 3'SL-PAA and 6'SLN-PAA, which contained, respectively, 3'-sialyllactose (the receptor determinant preferentially recognized by avian influenza viruses) and 6'-sialyl(N-acetyllactosamine) (the receptor determinant for human viruses). Avian and seal viruses bound 6'SLN-PAA very weakly, whereas the earliest available human and swine epidemic viruses bound this polymer with a higher affinity. For the H2 and H3 strains, a single mutation, 226Q-->L, increased binding to 6'SLN-PAA, while among H1 swine viruses, the 190E-->D and 225G-->E mutations in the HA appeared important for the increased affinity of the viruses for 6'SLN-PAA. Amino acid substitutions at positions 190 and 225 with respect to the avian virus consensus sequence are also present in H1 human viruses, including those that circulated in 1918, suggesting that substitutions at these positions are important for the generation of H1 human pandemic strains. These results show that the receptor-binding specificity of the HA is altered early after the transmission of an avian virus to humans and pigs and, therefore, may be a prerequisite for the highly effective replication and spread which characterize epidemic strains.

Global Epidemiology of Influenza: Past and Present

Abstract: Pandemics are the most dramatic presentation of influenza. Three have occurred in the twentieth century: the 1918 H1N1 pandemic, the 1957 H2N2 pandemic, and the 1968 H3N2 pandemic. The tools of molecular epidemiology have been applied in an attempt to determine the origin of pandemic viruses and to understand what made them such successful pathogens. An excellent example of this avenue of research is the recent phylogenetic analysis of genes of the virus that caused the devastating 1918 pandemic. This analysis has been used to identify evolutionarily related influenza virus genes as a clue to the source of the pandemic of 1918. Molecular methods have been used to investigate the avian H5N1 and H9N2 influenza viruses that recently infected humans in Hong Kong. Antigenic, genetic, and epidemiologic analyses have also furthered our understanding of interpandemic influenza. Although many questions remain, advances of the past two decades have demonstrated that several widely held concepts concerning the global epidemiology of influenza were false.

The annual report to the nation on the status of cancer, 1973–1997, with a special section on colorectal cancer

Abstract: BACKGROUND This annual report to the nation addresses progress in cancer prevention and control in the U.S. with a special section on colorectal cancer. This report is the joint effort of the American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries (NAACCR), and the Centers for Disease Control and Prevention (CDC), including the National Center for Health Statistics (NCHS). METHODS Age-adjusted rates were based on cancer incidence data from the NCI and NAACCR and underlying cause of death as compiled by NCHS. Joinpoint analysis was based on NCI Surveillance, Epidemiology, and End Results (SEER) program incidence rates and NCHS death rates for 1973–1997. The prevalence of screening examinations for colorectal cancer was obtained from the CDC's Behavioral Risk Factor Surveillance System and the NCHS's National Health Interview Survey. RESULTS Between 1990–1997, overall cancer incidence and death rates declined. Joinpoint analyses of cancer incidence and death rates confirmed the declines described in earlier reports. The incidence trends for colorectal cancer have shown recent steep declines for whites in contrast to a leveling off of the rates for blacks. State-to-state variations occurred in colorectal cancer screening prevalence as well as incidence and death rates. CONCLUSIONS The continuing declines in overall cancer incidence and death rates are encouraging. However, a few of the top ten incidence or mortality cancer sites continued to increase or remained level. For many cancer sites, whites had lower incidence and mortality rates than blacks but higher rates than Hispanics, Asian and Pacific Islanders, and American Indians/Alaska Natives. The variations in colorectal cancer incidence and death rates by race/ethnicity, gender, age, and geographic area may be related to differences in risk factors, demographic characteristics, screening, and medical practice. New efforts currently are underway to increase awareness of screening benefits and treatment for colorectal cancer. Cancer 2000;88:2398–424. © 2000 American Cancer Society.

Obstructive Lung Disease and Low Lung Function in Adults in the United States: Data From the National Health and Nutrition Examination Survey, 1988-1994

Abstract: Background Obstructive lung disease (OLD) is an important cause of morbidity and mortality in the US adult population. Potentially treatable mild cases of OLD often go undetected. This analysis determines the national estimates of reported OLD and low lung function in the US adult population. Methods We examined data from the Third National Health and Nutrition Examination Survey (NHANES III), a multistage probability representative sample of the US population. A total of 20,050 US adults participated in NHANES III from 1988 to 1994. Our main outcome measures were low lung function (a condition determined to be present if the forced expiratory volume in 1 second–forced vital capacity ratio was less than 0.7 and the forced expiratory volume in 1 second was less than 80% of the predicted value), a physician diagnosis of OLD (chronic bronchitis, asthma, or emphysema), and respiratory symptoms. Results Overall a mean (SE) of 6.8% (0.3%) of the population had low lung function, and 8.5% (0.3%) of the population reported OLD. Obstructive lung disease (age-adjusted to study population) was currently reported among 12.5% (0.7%) of current smokers, 9.4% (0.6%) of former smokers, 3.1% (1.1%) of pipe or cigar smokers, and 5.8% (0.4%) of never smokers. Surprisingly, 63.3% (0.2%) of the subjects with documented low lung function had no prior or current reported diagnosis of any OLD. Conclusions This study demonstrates that OLD is present in a substantive number of US adults. In addition, many US adults have low lung function but no reported OLD diagnosis, which may indicate the presence of undiagnosed lung disease.

Cigarette Smoking and Invasive Pneumococcal Disease

Abstract: Background Approximately half of otherwise healthy adults with invasive pneumococcal disease are cigarette smokers. We conducted a population-based case–control study to assess the importance of cigarette smoking and other factors as risk factors for pneumococcal infections. Methods We identified immunocompetent patients who were 18 to 64 years old and who had invasive pneumococcal disease (as defined by the isolation of Streptococcus pneumoniae from a normally sterile site) by active surveillance of laboratories in metropolitan Atlanta, Baltimore, and Toronto. Telephone interviews were conducted with 228 patients and 301 control subjects who were reached by random-digit dialing. Results Fifty-eight percent of the patients and 24 percent of the control subjects were current smokers. Invasive pneumococcal disease was associated with cigarette smoking (odds ratio, 4.1; 95 percent confidence interval, 2.4 to 7.3) and with passive smoking among nonsmokers (odds ratio, 2.5; 95 percent confidence interval, 1.2 ...

Changing patterns of infectious disease

Abstract: Despite a century of often successful prevention and control efforts, infectious diseases remain an important global problem in public health, causing over 13 million deaths each year. Changes in society, technology and the microorganisms themselves are contributing to the emergence of new diseases, the re-emergence of diseases once controlled, and to the development of antimicrobial resistance. Two areas of special concern in the twenty-first century are food-borne disease and antimicrobial resistance. The effective control of infectious diseases in the new millennium will require effective public health infrastructures that will rapidly recognize and respond to them and will prevent emerging problems.

The public health consequences of disasters.

Abstract: Although disasters have exacted a heavy toll of death and suffering, the future seems more frightening. Good disaster management must link data collection and analysis to the decision-making process. The overall objectives of disaster management from the viewpoint of public health are: 1) needs assessments; 2) matching available resources with defined needs; 3) prevention of further adverse health effects; 4) implementation of disease-control strategies; 5) evaluation of the effectiveness of the application of these strategies; and 6) improvement in contingency planning for future disasters. The effects of sudden-onset, natural disasters on humans are quantifiable. Knowledge of the epidemiology of deaths, injuries, and illnesses is essential to determine effective responses; provide public education; establish priorities, planning, and training. In addition, the temporal patterns for the medical care required must be established so that the needs in future disasters can be anticipated. This article discusses: 1) the nature of disasters due to sudden-onset, natural events; 2) the medical and health needs associated with such events and disasters; 3) practical issues of disaster responses; and 4) the advance organization and management of disasters. The discussion also includes: 1) discussions of past problems in disaster management including non-congruence between available supplies and the actual needs of the affected population; 2) information management; 3) needs assessments; 4) public health surveillance; and 5) linking information with decision-making. This discussion is followed by an analysis of what currently is known about the health-care needs during some specific types of sudden-onset, natural disasters: 1) floods; 2) tropical cyclones; 3) tornadoes; 4) volcanic eruptions; and 5) earthquakes. The article concludes with descriptions of some specific public-health problems associated with disasters including epidemics and disposition of corpses. All natural disasters are unique in that the regions affected have different social, economic, and health backgrounds. But, many similarities exist, and knowledge about these can ensure that the health and emergency medical relief and limited resources are well-managed.