Meningococcal disease in Los Angeles County, California, and among men in the county jails

The role of prisons in disseminating tuberculosis in Brazil: A genomic epidemiology study

Background

Globally, prisons are high-incidence settings for tuberculosis. Yet the role of prisons as reservoirs of M. tuberculosis, propagating epidemics through spillover to surrounding communities, has been difficult to measure directly.

Methods

To quantify the role of prisons in driving wider community M. tuberculosis transmission, we conducted prospective genomic surveillance in Central West Brazil from 2014 to 2019. We whole genome sequenced 1152 M. tuberculosis isolates collected during active and passive surveillance inside and outside prisons and linked genomes to detailed incarceration histories. We applied multiple phylogenetic and genomic clustering approaches and inferred timed transmission trees.

Findings

M. tuberculosis sequences from incarcerated and non-incarcerated people were closely related in a maximum likelihood phylogeny. The majority (70.8%; 46/65) of genomic clusters including people with no incarceration history also included individuals with a recent history of incarceration. Among cases in individuals with no incarceration history, 50.6% (162/320) were in clusters that included individuals with recent incarceration history, suggesting that transmission chains often span prisons and communities. We identified a minimum of 18 highly probable spillover events, M. tuberculosis transmission from people with a recent incarceration history to people with no prior history of incarceration, occurring in the state’s four largest cities and across sampling years. We additionally found that frequent transfers of people between the state’s prisons creates a highly connected prison network that likely disseminates M. tuberculosis across the state.

Interpretation

We developed a framework for measuring spillover from high-incidence environments to surrounding communities by integrating genomic and spatial information. Our findings indicate that, in this setting, prisons serve not only as disease reservoirs, but also disseminate M. tuberculosis across highly connected prison networks, both amplifying and propagating M. tuberculosis risk in surrounding communities.

Funding

Brazil’s National Council for Scientific and Technological Development and US National Institutes of Health.

Outbreaks of meningococcal meningitis in non-African countries over the last 50 years: a systematic review

Background

Meningococcal disease is caused by the bacteria Neisseria meningitidis, leading to substantial mortality and severe morbidity; with serogroups A, B, C, W135, X and Y most significant in causing disease. An outbreak is defined as multiple cases of the same serogroup occurring in a population over a short time-period. A systematic review was performed to gain insight into outbreaks of meningococcal disease and to describe the temporal pattern over the last 50 years in non-African countries.

Methods

PubMed and EMBASE were searched for English-language publications on outbreaks of meningococcal disease in non-African countries between January 1966 and July 2017, with an additional grey literature search. Articles and reports were considered eligible if they reported confirmed meningococcal outbreak cases, included the region, number of cases, and the start and end dates of the outbreak. Data on outbreaks was stratified by geographical region in accordance with the World Health Organization (WHO) regional classification, and case-fatality rates (CFRs) were calculated.

Results

Of the identified publications, 3067 were screened and 73 included, reporting data from 83 outbreaks. The majority of outbreaks were identified in the regions of the Americas (41/83 outbreaks), followed by the European region (30/83 outbreaks). In each of the Western Pacific, Eastern Mediterranean, and South-East Asian regions there were <10 outbreaks reported. The predominant serogroup in the majority of outbreaks was serogroup C (61%), followed by serogroup B (29%), serogroup A (5%) and serogroup W135 (4%). Outbreaks showed a peak in the colder months of both the Northern and Southern Hemispheres. Of the 54 outbreaks where CFR was calculable for all outbreak cases, it ranged from 0%-80%.

Conclusions

These data present a retrospective view of the patterns for meningococcal disease outbreaks in non-African countries, and provide valuable data for monitoring future changes in disease epidemiology and informing preventive measures.

Vaccinations in prisons: A shot in the arm for community health

From the first day of imprisonment, prisoners are exposed to and expose other prisoners to various communicable diseases, many of which are vaccine-preventable. The risk of acquiring these diseases during the prison sentence exceeds that of the general population. This excess risk may be explained by various causes; some due to the structural and logistical problems of prisons and others to habitual or acquired behaviors during imprisonment. Prison is, for many inmates, an opportunity to access health care, and is therefore an ideal opportunity to update adult vaccination schedules. The traditional idea that prisons are intended to ensure public safety should be complemented by the contribution they can make in improving community health, providing a more comprehensive vision of safety that includes public health.

Immunization Coverage Among Juvenile Justice Detainees

This study sought to (1) quantify the baseline immunization coverage of adolescents entering the juvenile justice system and (2) assess the effect of detention-based care on immunization coverage in youth. A cross-sectional retrospective chart review was performed of 279 adolescents detained at a large juvenile detention facility. Only 3% of adolescents had received all study immunizations prior to detention. Before detention, immunization coverage was significantly lower than that for the general adolescent population for all vaccines except the first doses of hepatitis A and varicella-zoster virus vaccines. Subsequent to detention, most individual immunization coverage levels increased and were significantly higher than in the general adolescent population. The routine administration of immunizations in the juvenile justice setting can help detained youth achieve levels of immunization coverage similar to their nondetained peers.

Distribution of A(H1N1)pdm09 Influenza Vaccine: Need for Greater Consideration of Smaller Jails

To identify factors associated with vaccine receipt among correctional facilities during the A(H1N1)pdm09 influenza pandemic, this study surveyed one third of U.S. correctional facilities. Analysis of the association of average daily population (ADP) on A(H1N1)pdm09 influenza vaccine receipt found that an ADP increase of 100 inmates resulted in a 32% increased likelihood of receiving influenza vaccine among smaller jails. Zero percent of large jails, 14% of federal prisons, 11% of nonfederal prisons, and 57% of small jails reported never receiving pandemic influenza vaccine. A qualitative assessment identified barriers to vaccine delivery, lessons learned from pandemic response, and recommendations for public health partners. Building stronger relationships between public health entities and correctional facilities to collaborate in influenza pandemic preparedness efforts may help protect correctional and community populations.

Association between population prevalence of smoking and incidence of meningococcal disease in Norway, Sweden, Denmark and the Netherlands between 1975 and 2009: a population-based time series analysis

OBJECTIVE

To investigate the relationship between the prevalence of smoking in the population and incidence of invasive meningococcal disease (IMD) among children under 5 years of age.

DESIGN

Retrospective, longitudinal, observational study. Poisson regression controlled for confounding factors.

SETTING

Norway, Sweden, Denmark and the Netherlands between 1975 and 2009.

POPULATION

Total population of approximately 35 million people in these four countries.

DATA SOURCES

Data were collected from the Ministries of Health, National Statistics Bureaus and other relevant national institutes.

RESULTS

In Norway, there was a significant positive relationship between the annual prevalence of daily smokers among individuals aged 25-49 years and the incidence of IMD in children under 5 years of age, unadjusted (RR=1.04-1.06, 95% CI 1.02 to 1.07, p<0.001) and after adjustment for time of year (quarter), incidence of influenza-like illness and household crowding (RR=1.05-1.07, 95% CI 1.03 to 1.09, p<0.001). Depending on age group, the risk of IMD increased by 5.2-6.9% per 1% increase in smoking prevalence among individuals aged 25-49 years in adjusted analyses. Using limited datasets from the three other countries, unadjusted analysis showed positive associations between IMD in children related to older smokers in Sweden and the Netherlands and negative associations related to younger smokers in Sweden. However, there were no demonstrable associations between incidence of IMD and prevalence of smoking, after adjustment for the same confounding variables.

CONCLUSIONS

The reduced incidence of IMD in Norway between 1975 and 2009 may partly be explained by the reduced prevalence of smoking during this period. High-quality surveillance data are required to confirm this in other countries. Strong efforts to reduce smoking in the whole population including targeted campaigns to reduce smoking among adults may have a role to play in the prevention of IMD in children.

Challenges to immunization: the experiences of homeless youth

BACKGROUND

Homelessness is a critical social issue, both a product of, and contributing to, poor mental and physical health. Over 150,000 young Canadians live on the streets. Homeless youth experience a high incidence of infectious diseases, many of which are vaccine preventable. Early departure from school and limited access to public health services makes them a particularly vulnerable high-risk group. This study explores challenges to obtaining essential vaccines experienced by homeless youth.

METHODS

A qualitative research study to explore knowledge, attitudes, beliefs, and experiences surrounding immunization of hard-to-reach homeless youth was designed. Participants were recruited for focus groups from Phoenix House and Shelter, a non-profit, community-based organization assisting homeless youth in Halifax, Nova Scotia, Canada. An experienced facilitator guided the recorded discussions. Transcripts of audiotapes were analyzed using a constant comparative method until data revealed a set of exemplars and themes that best captured participants' knowledge, attitudes, beliefs and experiences surrounding immunization and infectious diseases.

RESULTS

Important themes emerged from our analysis. Considerable variability in knowledge about immunization and vaccine preventable diseases was found. The homeless youth in the study had limited awareness of meningitis in contrast to a greater knowledge about sexually transmitted infections and influenza, gained during the H1N1/09 public health campaign. They recognized their poverty as a risk for contracting infectious diseases, along with their inability to always employ known strategies to prevent infectious diseases, due to circumstances. They showed considerable insight into the detrimental effects of poor hygiene, sleeping locations and risk behaviour. Interviewed homeless youth regarded themselves as good compliers of health professional advice and offered valuable suggestions to improve immunization in their population.

CONCLUSIONS

To provide effective public health interventions, it is necessary to consider the knowledge, attitudes, beliefs, and experiences of hard to reach, high risk groups. Our study shows that homeless youth are interested and capable in discussing immunization. Active targeting of homeless youth for public health immunization programs is needed. Working collaboratively with non-profit organizations that assist homeless youth provides an opportunity to increase their knowledge of infectious risks and to improve immunization strategies in this vulnerable group.

Epidemiological profile of meningococcal disease in the United States

Neisseria meningitidis is a leading cause of bacterial meningitis and other serious infections worldwide. The epidemiological profile of N. meningitidis is highly changeable, with great differences in disease incidence and serogroup distribution. Six serogroups (namely serogroups A, B, C, W-135, X, and Y) are responsible for most cases of meningococcal disease worldwide; the epidemiological profile of disease caused by each serogroup is unique. No vaccine is available for endemic disease caused by serogroup B strains. Two tetravalent (A/C/Y/W-135) meningococcal vaccines are licensed in the United States: a purified polysaccharide product and a polysaccharide-protein conjugate vaccine. The conjugate vaccine is recommended for all adolescents, although vaccine coverage remains low, and other groups at high risk of infection. A comprehensive program to prevent invasive meningococcal disease in the United States will require vaccination of infants; several conjugate vaccines for infants may become available in the near future. Broadly protective vaccines for endemic serogroup B disease are also needed.

Global epidemiology of meningococcal disease

As reviewed in this paper, meningococcal disease epidemiology varies substantially by geographic area and time. The disease can occur as sporadic cases, outbreaks, and large epidemics. Surveillance is crucial for understanding meningococcal disease epidemiology, as well as the need for and impact of vaccination. Despite limited data from some regions of the world and constant change, current meningococcal disease epidemiology can be summarized by region. By far the highest incidence of meningococcal disease occurs in the meningitis belt of sub-Saharan Africa. During epidemics, the incidence can approach 1000 per 100,000, or 1% of the population. Serogroup A has been the most important serogroup in this region. However, serogroup C disease has also occurred, as has serogroup X disease and, most recently, serogroup W-135 disease. In the Americas, the reported incidence of disease, in the range of 0.3-4 cases per 100,000 population, is much lower than in the meningitis belt. In addition, in some countries such as the United States, the incidence is at an historical low. The bulk of the disease in the Americas is caused by serogroups C and B, although serogroup Y causes a substantial proportion of infections in some countries and W-135 is becoming increasingly problematic as well. The majority of meningococcal disease in European countries, which ranges in incidence from 0.2 to 14 cases per 100,000, is caused by serogroup B strains, particularly in countries that have introduced serogroup C meningococcal conjugate vaccines. Serogroup B also predominates in Australia and New Zealand, in Australia because of the control of serogroup C disease through vaccination and in New Zealand because of a serogroup B epidemic. Based on limited data, most disease in Asia is caused by serogroup A and C strains. Although this review summarizes the current status of meningococcal disease epidemiology, the dynamic nature of this disease requires ongoing surveillance both to provide data for vaccine formulation and vaccine policy and to monitor the impact of vaccines following introduction.

Tobacco use increases susceptibility to bacterial infection

Active smokers and those exposed to secondhand smoke are at increased risk of bacterial infection. Tobacco smoke exposure increases susceptibility to respiratory tract infections, including tuberculosis, pneumonia and Legionnaires disease; bacterial vaginosis and sexually transmitted diseases, such as chlamydia and gonorrhoea; Helicobacter pylori infection; periodontitis; meningitis; otitis media; and post-surgical and nosocomial infections. Tobacco smoke compromises the anti-bacterial function of leukocytes, including neutrophils, monocytes, T cells and B cells, providing a mechanistic explanation for increased infection risk. Further epidemiological, clinical and mechanistic research into this important area is warranted.

Risk factors for meningococcal disease in students in grades 9-12

BACKGROUND

Meningococcal disease is a serious problem in adolescents, including high school students. Universal immunization of adolescents with meningococcal conjugate vaccine was recently recommended. We studied risk factors for meningococcal disease in students in grades 9-12.

METHODS

This was a matched case-control study using surveillance for meningococcal disease in students in grades 9-12 in sites throughout the United States. For each case-patient, up to 4 controls were selected from the home room classroom. All subjects answered an extensive questionnaire. Logistic regression was performed to identify risk factors associated with meningococcal disease. Meningococcal isolates were characterized.

RESULTS

Of 69 eligible patients, 49 (71%) were enrolled and had at least 1 control. Isolates were available for 59 (86%) cases. Attending at least 1 barbeque or picnic [matched odds ratio (MOR): 0.26, P value = 0.003] or school dance (MOR: 0.30, P = 0.04) were independently associated with decreased risk of meningococcal disease. Male gender (MOR: 2.94, P = 0.009), upper respiratory infection symptoms (MOR: 2.43, P = 0.04), marijuana use (MOR: 4.21, P = 0.009), and nightclub/disco attendance (MOR: 3.30, P = 0.04) were associated with increased risk. Among 54 students not from Oregon (where serogroup B strains predominate) with available serogroup, 38 (73.1%) cases were potentially vaccine preventable: 18 (34.6%) serogroup C, 19 (36.5%) serogroup Y, and 1 (1.9%) serogroup W-135.

CONCLUSIONS

Certain behaviors increase the risk of meningococcal infection, whereas others are associated with decreased risk. Most meningococcal disease in high school students can be prevented if recommendations on use of meningococcal conjugate vaccine are implemented.

Prospects for vaccine prevention of meningococcal infection

Neisseria meningitidis is the leading cause of bacterial meningitis in the United States and worldwide. A serogroup A/C/W-135/Y polysaccharide meningococcal vaccine has been licensed in the United States since 1981 but has not been used universally outside of the military. On 14 January 2005, a polysaccharide conjugate vaccine that covers meningococcal serogroups A, C, W-135, and Y was licensed in the United States for 11- to 55-year-olds and is now recommended for the routine immunization of adolescents and other high-risk groups. This review covers the changing epidemiology of meningococcal disease in the United States, issues related to vaccine prevention, and recommendations on the use of the new vaccine.

Children of prisoners: a growing public health problem

OBJECTIVES

To estimate the number and proportion of children in New South Wales affected by parental incarceration, and to describe the health impact of punitive incarceration on the children of prisoners.

METHODS

In 2001, NSW Corrections Health Service conducted a cross-sectional survey of prison inmates randomly selected from each of the 29 prisons in NSW, representing 11% of male and 30% of female inmates in the State. The survey included questions regarding parental status and number of children. A population model was developed, which incorporated increases in the prison population and recidivism, to estimate the number of children under 16 years of age in NSW ever having experienced parental incarceration.

RESULTS

In 2001, there were approximately 14,500 children under the age of 16 years in NSW who experienced parental incarceration during the year. It is estimated that in 2001 there were 60,000 children under 16 years in NSW who had ever experienced parental incarceration in their lifetime, representing 4.3% of all children and 20.1% of Indigenous children.

CONCLUSIONS

The number of children who have experienced parental incarceration is significant in NSW and across Australia. Indigenous children are much more likely to experience parental incarceration than non-Indigenous children.

IMPLICATIONS

Children of prisoners are at high risk of negative health outcomes and are themselves at an increased risk of offending later in life. The needs of these children must be recognised and policies introduced to reduce the adversities they face. The social, politico-legal and economic conditions that are contributing to the continuing rise in incarceration rates must be recognised, and measures must be taken to reduce this trend.

Development of immunity to serogroup B meningococci during carriage of Neisseria meningitidis in a cohort of university students

Understanding the basis of protective immunity is a key requirement for the development of an effective vaccine against infection with Neisseria meningitidis of serogroup B. We have conducted a longitudinal study into the dynamics of meningococcal acquisition and carriage in first-year university students. The detection of carriage of serogroup B meningococci correlated with an increase in detection of serum bactericidal activity (SBA) against both colonizing and heterologous serogroup B strains. Once induced, SBA remained high throughout the study. Although students showed increases in antibodies reactive with capsular polysaccharide and lipopolysaccharide (LPS), these antibody responses were transitory, and their decline was not accompanied by a corresponding decline in SBA. In contrast, there was a significant correlation between the presence of antibodies to the PorA outer membrane protein and SBA against both homologous and heterologous strains. SBA induced by a PorA-negative mutant confirmed the contribution of PorA to heterologous activity. Increases in SBA against a range of serogroup B strains were also observed in students in whom no meningococcal carriage was detected. This heterologous protection could not be associated with the presence of antibodies reacting with capsule, LPS, PorA, PorB, Rmp, Opa, Opc, or pilin, demonstrating that other, as yet unidentified, antigens contribute to the development of immunity to serogroup B meningococci. Identification of such antigens with the ability to induce an effective cross-reactive bactericidal response to a range of strains would be a major step in the production of a universally effective vaccine against infections caused by serogroup B meningococci.

Pox in the docks: varicella outbreak in an Australian prison system

OBJECTIVES

1. Describe an outbreak of varicella in a prison system. 2. Highlight the risks of disease transmission within the prison environment. 3. Promote infection control guidelines for high-risk sub-groups within the prison system, including the application of quarantine.

SETTING

Four prisons, one prison hospital, the prison transport system, one courthouse.

MAIN OUTCOME MEASURES

Number of cases of varicella infection; reported varicella immunity status of cases and contacts; immunity status of known HIV antibody positive inmates.

RESULTS

Five cases of chickenpox were identified. There were 23 contacts of the Index Case occurring during transport between prison and court and whilst being held in the court holding cells. Two of these contacts developed chickenpox despite having given a prior history of infection. There were over 300 inmates exposed to varicella zoster virus (VZV) during the outbreak, including one HIV antibody positive inmate who had serologically confirmed immunity. This inmate developed shingles following exposure to VZV from one of the cases.

CONCLUSIONS

There is an elevated risk of respiratory transmission of infections such as chickenpox in prisons. Clear guidelines should be in place to protect HIV antibody positive people, pregnant women, and others who are at increased risk of complications from such infections. In the case of varicella, all inmates and staff without documented immunity should be screened to determine immunity, and if non-immune, should be offered VZV vaccination. Every effort should be made to prevent HIV antibody positive inmates being exposed to varicella, regardless of their varicella immunity status. If an HIV antibody positive inmate, who is known to be non-immune is exposed to varicella, Varicella Zoster immunoglobulin should be given within 96 h.

Meningococcal carriage among local inhabitants during the pilgrimage 2000-2001

The first international outbreak of Neisseria meningitidis serogroup W135 occurred in 2000, in direct association with the annual Hajj in Saudi Arabia. In anticipation of the following Hajj, we conducted a survey of oropharyngeal carriage rates of N. meningitidis both pre- and post-pilgrimage in the King Khalid National Guard Hospital (KKNGH) employees preparing to attend the Hajj. These KKNGH employees were native to the Mecca-Jeddah area. Pre-Hajj throat cultures were obtained 1 week prior to Hajj, and post-Hajj cultures within 10 days after completing the Hajj pilgrimage. A total of 327 throat culture samples were collected from 218 persons. Overall meningococcal carriage rate was found to be 4.7%. Serogroup W135 accounted for 40% of all recovered pre-Hajj strains of N. meningitidis. Only one post-Hajj sample was positive for N. meningitidis W135. This high rate of colonization with N. meningitidis serogroup W135 indicates this strain predominates amongst the population indigenous to the Mecca-Jeddah area. This 'nidus' of N. meningitidis W135 is a potential reservoir for future outbreaks. More worrying, there is real risk of future W135 endemicity in this vulnerable local population. These preliminary findings warrant larger surveillance studies examining both transmission and carrier rate acquisition of N. meningitidis in the Mecca-Jeddah area. These vital data are needed to curb further epidemic outbreaks during future Hajj pilgrimages.

Sequence diversity of Neisseria meningitidis 16S rRNA genes and use of 16S rRNA gene sequencing as a molecular subtyping tool

We investigated the diversity of the primary sequences of 16S rRNA genes among Neisseria meningitidis strains (Men) and evaluated the use of this approach as a molecular subtyping tool. We aligned and compared a 1,417-bp fragment of the 16S rRNA gene from 264 Men strains of serogroups A, B, C, and Y (MenA, MenB, MenC, and MenY, respectively) isolated throughout the world over a 30-year period. Thirty-one positions of difference were found among 49 16S types: differences between types ranged from 1 to 14 positions (0.07 to 0.95%). 16S types and serogroups were highly associated; only 3 out 49 16S types were shared by two or more serogroups. We have identified 16S types that are exclusively associated with strains of certain hypervirulent clones: 16S type 5 with MenA subgroup III, 16S type 4 with the MenB electrophoretic type 5 (ET-5) complex, and 16S types 12 and 13 with MenC of the ET-37 complex. For MenC strains, 16S sequencing provided the highest sensitivity and specificity and the best overall association with the outbreak-related versus sporadic isolates when compared with pulsed-field gel electrophoresis, multilocus enzyme electrophoresis, and multilocus sequence typing. We demonstrated for the first time an unexpected diversity among 16S rRNA genes of Men strains, identified 16S types associated with well-defined hypervirulent clones, and showed the potential of this approach to rapidly identify virulent strains associated with outbreaks and/or an increased incidence of sporadic disease.

Evaluation of pulsed-field gel electrophoresis in epidemiological investigations of meningococcal disease outbreaks caused by Neisseria meningitidis serogroup C

Since 1990, the frequency of Neisseria meningitidis serogroup C (NMSC) outbreaks in the United States has increased. Based on multilocus enzyme electrophoresis (MEE), the current molecular subtyping standard, most of the NMSC outbreaks have been caused by isolates of several closely related electrophoretic types (ETs) within the ET-37 complex. We chose 66 isolates from four well-described NMSC outbreaks that occurred in the United States from 1993 to 1995 to evaluate the potential of pulsed-field gel electrophoresis (PFGE) to identify outbreak-related isolates specific for each of the four outbreaks and to differentiate between them and 50 sporadic isolates collected during the outbreak investigations or through active laboratory-based surveillance from 1989 to 1996. We tested all isolates collected during the outbreak investigations by four other molecular subtyping methods: MEE, ribotyping (ClaI), random amplified polymorphic DNA assay (two primers), and serotyping and serosubtyping. Among the 116 isolates, we observed 11 clusters of 39 NheI PFGE patterns. Excellent correlation between the PFGE and the epidemiological data was observed, with an overall sensitivity of 85% and specificity of 71% at the 95% pattern relatedness breakpoint using either 1.5 or 1.0% tolerance. For all four analyzed outbreaks, PFGE would have given public health officials additional support in declaring an outbreak and making appropriate public health decisions.

Cigarette smoking and invasive pneumococcal disease. Active Bacterial Core Surveillance Team

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 to 5.1) after adjustment by logistic-regression analysis for age, study site, and independent risk factors such as male sex, black race, chronic illness, low level of education, and living with young children who were in day care. There were dose-response relations for the current number of cigarettes smoked per day, pack-years of smoking, and time since quitting. The adjusted population attributable risk was 51 percent for cigarette smoking, 17 percent for passive smoking, and 14 percent for chronic illness.

CONCLUSIONS

Cigarette smoking is the strongest independent risk factor for invasive pneumococcal disease among immunocompetent, nonelderly adults. Because of the high prevalence of smoking and the large population attributable risk, programs to reduce both smoking and exposure to environmental tobacco smoke have the potential to reduce the incidence of pneumococcal disease.

Update on meningococcal disease with emphasis on pathogenesis and clinical management

The only natural reservoir of Neisseria meningitidis is the human nasopharyngeal mucosa. Depending on age, climate, country, socioeconomic status, and other factors, approximately 10% of the human population harbors meningococci in the nose. However, invasive disease is relatively rare, as it occurs only when the following conditions are fulfilled: (i) contact with a virulent strain, (ii) colonization by that strain, (iii) penetration of the bacterium through the mucosa, and (iv) survival and eventually outgrowth of the meningococcus in the bloodstream. When the meningococcus has reached the bloodstream and specific antibodies are absent, as is the case for young children or after introduction of a new strain in a population, the ultimate outgrowth depends on the efficacy of the innate immune response. Massive outgrowth leads within 12 h to fulminant meningococcal sepsis (FMS), characterized by high intravascular concentrations of endotoxin that set free high concentrations of proinflammatory mediators. These mediators belonging to the complement system, the contact system, the fibrinolytic system, and the cytokine system induce shock and diffuse intravascular coagulation. FMS can be fatal within 24 h, often before signs of meningitis have developed. In spite of the increasing possibilities for treatment in intensive care units, the mortality rate of FMS is still 30%. When the outgrowth of meningococci in the bloodstream is impeded, seeding of bacteria in the subarachnoidal compartment may lead to overt meningitis within 24 to 36 h. With appropriate antibiotics and good clinical surveillance, the mortality rate of this form of invasive disease is 1 to 2%. The overall mortality rate of meningococcal disease can only be reduced when patients without meningitis, i.e., those who may develop FMS, are recognized early. This means that the fundamental nature of the disease as a meningococcus septicemia deserves more attention.

Risk factors for carriage of Neisseria meningitidis during an outbreak in Wales

In a school outbreak of meningococcal disease in Wales, we compared risk factors for the carriage of Neisseria meningitidis B15 P1.16 with carriage of any meningococci. Students had throat swabs and completed a questionnaire. Sixty (7.9%) carried meningococci; risk for carriage was higher in those >14 years of age.

Update on meningococcal disease with emphasis on pathogenesis and clinical management

The only natural reservoir of Neisseria meningitidis is the human nasopharyngeal mucosa. Depending on age, climate, country, socioeconomic status, and other factors, approximately 10% of the human population harbors meningococci in the nose. However, invasive disease is relatively rare, as it occurs only when the following conditions are fulfilled: (i) contact with a virulent strain, (ii) colonization by that strain, (iii) penetration of the bacterium through the mucosa, and (iv) survival and eventually outgrowth of the meningococcus in the bloodstream. When the meningococcus has reached the bloodstream and specific antibodies are absent, as is the case for young children or after introduction of a new strain in a population, the ultimate outgrowth depends on the efficacy of the innate immune response. Massive outgrowth leads within 12 h to fulminant meningococcal sepsis (FMS), characterized by high intravascular concentrations of endotoxin that set free high concentrations of proinflammatory mediators. These mediators belonging to the complement system, the contact system, the fibrinolytic system, and the cytokine system induce shock and diffuse intravascular coagulation. FMS can be fatal within 24 h, often before signs of meningitis have developed. In spite of the increasing possibilities for treatment in intensive care units, the mortality rate of FMS is still 30%. When the outgrowth of meningococci in the bloodstream is impeded, seeding of bacteria in the subarachnoidal compartment may lead to overt meningitis within 24 to 36 h. With appropriate antibiotics and good clinical surveillance, the mortality rate of this form of invasive disease is 1 to 2%. The overall mortality rate of meningococcal disease can only be reduced when patients without meningitis, i.e., those who may develop FMS, are recognized early. This means that the fundamental nature of the disease as a meningococcus septicemia deserves more attention.

Epidemiology of bacterial meningitis

Bacterial meningitis caused by Haemophilus influenzae type B (Hib) has almost disappeared from the United States, Canada, and other countries that have implemented routine vaccination with Hib conjugate vaccines. The overall incidence of meningitis in these countries has declined by more than 50%, and the age distribution of susceptibility has shifted, so that the disease is now more common in adults than in children. Another new feature of the epidemiology of bacterial meningitis has been the occurrence of clusters of meningococcal disease. Such clusters have been school related, mainly in adolescents, and most clusters have been associated with a clone of group C, serotype 2a. The role of cigarette smoking as a risk factor for bacterial meningitis has been confirmed and adds urgency to the efforts to control smoking in adolescents and young adults.

Cleavase fragment length polymorphism analysis of Neisseria meningitidis basic metabolic genes

Cleavase fragment length polymorphism (CFLP) is a subtyping system based on the property of the enzyme cleavase to recognize junctions between single- and double-stranded regions of DNA formed after denaturation and cooling. To assess the capacity of CFLP for discriminating Neisseria meningitidis serogroup B strains belonging to the electrophoretic type (ET) 5 (ET-5) complex from other serogroup B strains, 30 serogroup B N. meningitidis isolates were subtyped by CFLP with internal fragments of five housekeeping genes, adk, aspC, carA, dhp, and glnA. Two genes (glnA and carA) which demonstrated a high degree of diversity for the serogroup B isolates were then used to further evaluate the suitability of CFLP for screening 50 serogroup C N. meningitidis outbreak-associated and sporadic-case isolates with a single metabolic gene. The results were compared to those from multilocus enzyme electrophoresis (MEE), the current standard subtyping method. CFLP was able to distinguish the ET-5 complex isolates from other serogroup B isolates as efficiently as MEE. Furthermore, CFLP analysis of a single gene was sufficient to identify and cluster the serogroup C isolates belonging to the ET-37 complex from other, unrelated serogroup C isolates but was not capable of differentiating between the isolates of the major individual ETs of this complex (ET-17 and ET-24) causing most serogroup C meningococcal disease outbreaks in the United States. CFLP based on a single gene with a high degree of diversity but not under selective pressure can be applied to the rapid screening of a large number of isolates related to the recognized epidemic complex ET-5 or ET-37. Additionally, CFLP can be used as an initial screening tool to survey the amount of diversity in genes that might be used to develop a DNA sequence-based subtyping system.

Maternal cigarette smoking and invasive meningococcal disease: a cohort study among young children in metropolitan Atlanta, 1989-1996

OBJECTIVES

This study assessed the association between maternal cigarette smoking during pregnancy and the risk of invasive meningococcal disease during early childhood.

METHODS

Using a retrospective cohort study design, cases from an active surveillance project monitoring all invasive meningococcal disease in the metropolitan Atlanta area from 1989 to 1995 were merged with linked birth and death certificate data files. Children who had not died or acquired meningococcal disease were assumed to be alive and free of the illness. The Cox proportional hazards analysis was used to assess the independent association between maternal smoking and meningococcal disease.

RESULTS

The crude rate of meningococcal disease was 5 times higher for children whose mothers smoked during pregnancy than for children whose mothers did not smoke (0.05% vs 0.01%). Multivariate analysis revealed that maternal smoking (risk ratio [RR] = 2.9; 95% confidence interval [CI] = 1.5, 5.7) and a mother's having fewer than 12 years of education (RR = 2.1; 95% CI = 1.0, 4.2) were independently associated with invasive meningococcal disease.

CONCLUSIONS

Maternal smoking, a likely surrogate for tobacco smoke exposure following delivery, appears to be a modifiable risk factor for sporadic meningococcal disease in young children.