Meningococcal disease in Norway 1992-1995. Epidemiology and fatality

An epidemic of meningococcal disease in children in North Norway in the 1970s and 1980s was dominated by a hypervirulent group B strain

AIM

We examined children hospitalised for invasive meningococcal disease, a leading cause of paediatric sepsis, in Troms County, North Norway, from 1973 to 2016, including the epidemic in the 1970s and 1980s.

METHODS

This study was a retrospective review of children under the age of 15 years who were hospitalised for meningococcal disease at the University Hospital of North Norway and Harstad Hospital. We studied hospital and bacteriological records to determine the incidence rates and phenotypes involved.

RESULTS

There were 300 cases under 15 years and an incidence rate of 17 per 100,000 cases for 1973-2016. This was broken down into the following: 1973-1980 (n = 130, 49), 1981-1990 (n = 129, 39), and 1991-2016 (n = 41, 4.7), respectively. There were 21 (7%) deaths. Phenotype B:15:P1.7,16 was more common than the other phenotypes in the epidemic period before 1990 than after 1990 (p = 0.02) and had a significantly lower mortality rate than the other phenotypes (p = 0.04). Later years showed a more heterogenous phenotype distribution. Serogroup B was the dominant serogroup.

CONCLUSION

The B:15:P1.7,6 strain was more prevalent during the Norwegian epidemic of invasive meningococcal disease, but had a significantly lower mortality rate. The phenotype distribution was more heterogeneous after 1990. The dominant serogroup was B.

Mortalidade por doença meningocócica no Município de São Paulo, Brasil: características e preditores

O estudo objetiva descrever a magnitude, as características da mortalidade e da letalidade por doença meningocócica e investigar preditores de óbito por essa causa, no Município de São Paulo, Brasil, de 1986 a 2004. Utilizou-se a regressão logística múltipla não condicional para a investigação dos preditores de óbitos. Foram estudados 10.087 casos de doença meningocócica no município. A taxa anual média de mortalidade foi de 1,0/100 mil habitantes/ano, variando de 0,2 a 1,8; a letalidade foi de 20,5% com grandes diferenças segundo idade, sorogrupo e tipo de hospital. Os preditores de óbito por doença meningocócica foram idade, especialmente as faixas etárias de um a dois anos e de 40 anos ou mais e o sorogrupo W. Os resultados obtidos podem contribuir para a elaboração de políticas públicas com foco na organização da assistência hospitalar e elaboração de protocolos que promovam a maior efetividade do tratamento e a aplicação de estratégias de vacinação que diminuam a incidência nos grupos de maior risco para óbito por doença meningocócica.

An epidemiological review of changes in meningococcal biology during the last 100 years

AIM

The aim of this study was to assess changes in trends of meningococcal disease and strain diversity of Neisseria meningitidis in Europe, South America, and Africa over the last 100 years.

METHODS

Healthcare databases and sources of grey literature were searched in 2012 and records were screened against the protocol eligibility criteria using a three-stage sifting process. Studies included in the review were subject to data extraction. Results were summarised using a narrative approach.

RESULTS

Serogroup A was the dominant cause of invasive meningococcal disease in Europe before and during World Wars I and II. Whilst serogroup B has been dominant from the 1970s in Europe and the 1980s in South America, outbreaks have emerged associated with serogroups W135 and Y in the twenty-first century. There has been a shift in the age groups affected by invasive meningococcal disease with an increase in incidence among the elderly associated with serogroup Y and a decline in serogroup C among adolescent populations. Recent outbreaks of serogroup W135 have occurred in some countries in South America. The epidemiological trend of invasive meningococcal disease has remained largely static across Africa and dominated by serogroup A although recently serogroups X and W135 have accounted for a large proportion of morbidity and mortality.

CONCLUSION

The epidemiology of N. meningitidis has been dynamic in Europe and South America especially over the last 30 years. Routine vaccination with serogroup C vaccines has led to reduced carriage and incidence of invasive meningococcal disease and herd immunity.

Global epidemiology of invasive meningococcal disease

Neisseria meningitidis is one of the leading causes of bacterial meningitis globally and can also cause sepsis, pneumonia, and other manifestations. In countries with high endemic rates, the disease burden places an immense strain on the public health system. The worldwide epidemiology of invasive meningococcal disease (IMD) varies markedly by region and over time. This review summarizes the burden of IMD in different countries and identifies the highest-incidence countries where routine preventive programs against Neisseria meningitidis would be most beneficial in providing protection. Available epidemiological data from the past 20 years in World Health Organization and European Centre for Disease Prevention and Control collections and published articles are included in this review, as well as direct communications with leading experts in the field. Countries were grouped into high-, moderate-, and low-incidence countries. The majority of countries in the high-incidence group are found in the African meningitis belt; many moderate-incidence countries are found in the European and African regions, and Australia, while low-incidence countries include many from Europe and the Americas. Priority countries for vaccine intervention are high- and moderate-incidence countries where vaccine-preventable serogroups predominate. Epidemiological data on burden of IMD are needed in countries where this is not known, particularly in South- East Asia and Eastern Mediterranean regions, so evidence-based decisions about the use of meningococcal vaccines can be made.

No increase in headache after previous intracranial infections: a historical cohort study (HUNT)

BACKGROUND AND PURPOSE

Despite the absence of robust scientific evidence, it is today generally accepted that the acute headache typical for intracranial infections can develop into permanent headache complaints. This widespread concept was explored in the first, large, longitudinal, population-based study.

METHODS

Data on confirmed exposure to intracranial infections amongst all adult inhabitants in a geographical area during a 20-year period were assembled from hospital records. Surviving individuals were later invited to the third Nord-Trøndelag Health Survey (HUNT 3), where 39,690 (42%) of 94,194 invited inhabitants aged ≥20 years responded to a validated headache questionnaire. Using logistic regression, the 1-year prevalence of headache and its subtypes according to the diagnostic criteria of the International Headache Society was assessed and compared between those with and without previous confirmed intracranial infection. Age and sex were used as covariates.

RESULTS

Overall, 43 participants were identified with earlier intracranial infection, whereof three had more than one infection: bacterial meningitis (n=19), lymphocytic meningitis (n=18), encephalitis (n=9), and brain abscess (n=1).The mean interval from infection to participation in HUNT 3 was 11.2 (range 1.5-19.7) years. There was no significant increase in the prevalence of headache (OR 1.10, 95% CI 0.58-2.07), its subtypes (migraine, or tension-type headache), or chronic daily headache (OR 1.85, 95% CI 0.45-7.68) amongst participants with previous intracranial infection compared with the surrounding population.

CONCLUSIONS

This study challenges the existence of chronic post-bacterial meningitis headache and does not indicate the presence of other long-term headaches induced by intracranial infection.

A surveillance network for meningococcal disease in Europe

Between 1999 and 2004, the European Union Invasive Bacterial Infections Surveillance Network (EU-IBIS) received c. 50,000 reports of meningococcal disease from 27 participating countries. Analysis has demonstrated a major decline in the incidence of invasive disease in those countries that have introduced routine vaccination against serogroup C infection. The establishment of rapid reporting of W135 and B2a/B2b strains has been able to provide early reassurance that these strains are not emerging as major public health problems in Europe. Between September 2001 and February 2005, the EU-MenNet project offered further opportunities for enhancing this data resource. Collaborative projects included: improving the EU-IBIS website; reviewing case ascertainment in Europe; reviewing cost-effectiveness studies for meningococcal serogroup C conjugate (MCC) vaccination; international comparisons of MCC vaccine efficacy; and mathematical modelling studies. In addition, linking of data from the European Meningococcal Multi-locus Sequence Type Centre to epidemiological data was performed. Particular clonal complexes were found to be preferentially associated with certain serogroups. Case fatality was also found to vary with clonal complex, suggesting that genotype can be a marker for hypervirulence. The importance of close collaboration between networks of epidemiologists, microbiologists, and the wider scientific and public health community is demonstrated.

High case-fatality rates of meningococcal disease in Western Norway caused by serogroup C strains belonging to both sequence type (ST)-32 and ST-11 complexes, 1985-2002

A total of 293 meningococcal disease (McD) patients from Western Norway hospitalized during 1985-2002 were examined for risk factors related to death. The case-fatality rate (CFR) increased from 4% during 1985-1993 to 17% during 1994-2002. We analysed the phenotypic and genotypic characteristics of the meningococcal patient isolates, with the aim of identifying whether highly virulent meningococcal strains contributed to the increased CFR. The Norwegian epidemic strain B:15:P1.7,16/ST-32 complex was overall the most common phenotype/genotype (n=75) and caused most deaths (n=9; CFR 12.0%). However, fatality was significantly associated with disease caused by serogroup C meningococcal strains; C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains, which had the highest CFRs of 21.1% and 18.2% respectively. Serogroup B strains of the ST-32 complex differing by serotype and/or serosubtype from the epidemic strain had a CFR of 5.1%, while the CFR of disease caused by other strains (all phenotypes and genotypes pooled) was 2.2%. The distribution of phenotypes/clonal complexes varied significantly between 1985-1993 and 1994-2002 (P<0.001); B:15/ST-32 complex strains decreased whereas both C:15:P1.7,16/ST-32 complex strains and strains with other phenotypes/clonal complexes increased. Our results indicate that C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains were highly virulent strains and contributed to the high CFR of McD in patients from Western Norway. To reduce fatality, rapid identification of such virulent strains is necessary. In addition, early and specific measures should include public information, vaccination of populations at risk of disease and carriage eradication, when clustering of patients occurs.

Variations in case fatality and fatality risk factors of meningococcal disease in Western Norway, 1985-2002

In a retrospective epidemiological study, 293 meningococcal disease patients hospitalized during 1985-2002, were examined for fatality and risk factors related to death. The overall case fatality rate (CFR) was 8.2%, but increased from 4% during 1985-1993 to 17% during 1994-2002. The latter 9-year period was characterized by more serogroup C infections and more patients with thrombocytopenia on admission to hospital. All patients categorized as meningitis on admission survived. Of the 24 patients who died, 21 had meningococcal skin rash on admission, 23 had an onset to admission time of < or =24 h, and 16 had severe septicaemia with hypotension and/or ecchymoses without meningitis on admission. By multivariate analyses, a short onset to admission time, >50 petechiae, thrombocytopenia and severe septicaemia on admission were associated with fatality. More lives could be saved through earlier admission to hospital. This can be achieved through more information to the public about the early signs of meningococcal septicaemia, with the recommendation to look for skin rash in patients with acute fever during the first day and night.

Are antibodies to the capsular polysaccharide of Neisseria meningitidis group B and Escherichia coli K1 associated with immunopathology?

As polysialic acid (PSA), the capsule of Group B meningococcus (GBM) and Escherichia coli K1, is a component of mammalian glycopeptides, there is concern that vaccines against PSA could induce immunopathology. Purified PSA is not immunogenic; however, as a component of bacteria or bound to proteins, it induces protective antibodies. In this review, we did not unearth data indicating an association of IgG anti-PSA with immunopathology in experimental animals or humans. We found no increased incidence of autoimmunity from GBM infections in our review of the natural history/sequellae of Neisseria meningitis infections. Accordingly, we propose that clinical trials of PSA conjugate vaccines, be considered.

Neisseria meningitidis phenotypic markers and septicaemia, disease progress and case-fatality rate of meningococcal disease: a 20-year population-based historical follow-up study in a Danish county

The incidence rate (IR) and case-fatality rate (CFR) of meningococcal disease increased during the late 1980s and early 1990s in North Jutland County, Denmark. We examined the hypothesis that phenotypic markers of Neisseria meningitidis are predictors of septicaemia with or without meningitis, rapid disease progress and fatal outcome of meningococcal disease and we studied whether changes in IR and CFR over time might be related to emergence or spread of certain phenotypes. This follow-up study was based on a complete registration of 413 cases of meningococcal disease in North Jutland County during 1980-99. Phenotypic markers included serogroup, serotype and serosubtype. A complete phenotype was available for 315 cases (76 %); 100 (32 %) strains were phenotype B : 15 : P1.7,16 and 31 (10 %) were C : 2a : P1.2,5. Septicaemia without meningitis was less common in cases with B : 15 : P1.7,16 and C : 2a : P1.2,5 strains. No association was found between phenotype and rapid disease progress. The overall CFR was 12 %. An increased CFR was associated with phenotypes B : 15 : P1.7,16 [odds ratio (OR) 2.8, 95 % confidence interval (CI) 1.2-18.5] and C : 2a : P1.2,5 (OR 5.2, 95 % CI 1.6-16.4) when compared with other phenotypes. The prevalence of B : 15 : P1.7,16 strains increased gradually during the study period and the CFR increased from 8 % during 1980-89 to 19 % during 1990-99, although the CFR for other phenotypes also increased. The CFR for C : 2a : P1.2,5 remained high ( approximately 20 %), but the contribution of this phenotype to the overall CFR decreased during the study period. In conclusion, phenotypes B : 15 : P1.7,16 and C : 2a : P1.2,5 were predictors of an increased CFR. The high prevalence of phenotype B : 15 : P1.7,16 contributed to increased overall IR and CFR during 1990-99.

Fatal outcome from meningococcal disease--an association with meningococcal phenotype but not with reduced susceptibility to benzylpenicillin

Penicillin has been the mainstay of treatment for meningococcal disease. Isolates of Neisseria meningitidis that are less susceptible to penicillin have been reported in several countries and in recent years have become more common. The clinical significance of this reduced susceptibility has not been investigated on a large scale. Hence, N. meningitidis isolates from culture-confirmed cases of meningococcal disease in England and Wales, between 1993 and 2000, were routinely serogrouped, serotyped and tested for susceptibility to penicillin. These data were linked to death registrations and analysed retrospectively. The changing trends in susceptibility were described and multivariate logistic regression was used to examine associations between strain characteristics and fatal outcome. The frequency of N. meningitidis isolates less susceptible to penicillin increased from < 6% in 1993 to > 18% in 2000. In particular, isolates expressing serogroup C with serotype 2b and serogroup W135 had a higher frequency of reduced penicillin susceptibility (49% and 55%, respectively). There was no evidence of an association between fatal outcome and infection with a less penicillin-susceptible isolate. Fatal outcome was associated with serogroup and serotype, with the odds of death for cases infected with C:2a and B:2a strains three-fold higher when compared with the baseline. For this large dataset the serogroup and serotype of the infecting strain influenced mortality from meningococcal disease and may be markers for hypervirulence. No association was found between reduced penicillin susceptibility and fatal outcome, but the increasing frequency of isolates less susceptible to penicillin highlights the need for continued surveillance.

Influence of serogroup on the presentation, course, and outcome of invasive meningococcal disease in children in the Republic of Ireland, 1995-2000

To test the hypothesis that the infecting meningococcal serogroup modulates the presentation, course, and outcome of invasive meningococcal disease (IMD), we performed a retrospective review of cases of IMD in 407 children from 2 tertiary referral centers and 2 regional centers in Ireland. Patients infected with serogroup C meningococci (n=104) were older than those infected with serogroup B (n=303; median, 2.5 vs. 1.5 years; P=.04); all other demographic and clinical parameters were similar for the 2 groups. Among serogroup B patients, mortality was 3.6% and morbidity was 10%; for serogroup C patients, mortality was 4.8% and morbidity was 12.5% (P=.81 and P=.76, respectively). Serogroup C-associated sequelae more often were multiple (P=.003). Despite the introduction of serogroup C conjugate vaccine into the routine immunization schedule of some countries, ongoing morbidity from IMD is anticipated, because group B disease was very similar to group C disease in this pediatric population.

Meningococcal disease in Slovenia (1993-1999): serogroups and susceptibility to antibiotics. Slovenian Meningitis Study Group

The epidemiology of meningococcal disease was studied prospectively in Slovenia from 1993 to 1999 in children and from 1995 to 1999 in adults. Patients with meningococci isolated from normally sterile body sites were included in the study. Altogether 75 patients (57 children, 18 adults) were found with meningococcal diseases. The overall yearly incidence was 0.43 per 100000 inhabitants. The highest annual incidence (18.5/100000) was found in children between 1 month and 1 year of age. The case to fatality ratio was 4.1%. Group B meningococci were isolated most frequently (84.7%), followed by group C (11.1%). In six patients (8.3%) isolates were less susceptible to penicillin. Four of these were successfully treated with penicillin alone.

[Fatality rate in the epidemiology of meningococcal disease: study in the region of Campinas, SP, Brazil, 1993 to 1998]

OBJECTIVE

To analyze the trends of the meningococcal disease cumulative incidence and case-fatality rate in the region of Campinas, Brazil, an area that encircles five cities and 1.2 million inhabitants, from 1993 to 1998.

METHODS

A longitudinal retrospective study of all case records (375) obtained from the regional epidemiological surveillance system was carried out. A logistic regression analysis allowed identifying the risk factors related to fatal outcomes of meningococcal disease.

RESULTS

The highest fatality rates (23.8%) were seen in the period of 1996 and 1997, coinciding with the incidence peaks of serogroup B Neisseria and a high percentage of septicemia cases. Also at the same period there was registered a poor etiological investigation of the cases. A seasonal pattern and the predomination of strains B:4:P1.15 and C:2b:P1.3 were observed. In the logistic regression analysis, the risk factors related to fatality were: septicemia with or without meningitis (adjusted odds ratio [OR(aj)] = 13.88 and 95% confidence interval [CI] = 4.68 - 42.13); age over 30 years (OR(aj) = 6.42; CI = 2.32 - 17.80); age under 1 year (OR(aj) = 2.95; CI = 1.55 - 5.63); and serogroup B (OR(aj) = 2.33; CI = 1.14 - 4.79).

CONCLUSIONS

Septicemia, age and serogroup were predictive variables related to a fatal outcome. In 1996 and 1997, case-fatality rates were high, indicating the need to further assessment of the quality of the services delivered and their readiness to take preventive action. The lack of etiological identification in many cases precluded more accurate inferences about the epidemiological behavior of Neisseria meningitidis in the region.

Genetic basis for biosynthesis, structure, and function of meningococcal lipooligosaccharide (endotoxin)

The exclusive human pathogen Neisseria meningitidis expresses lipooligosaccharide (LOS), an endotoxin that is structurally distinct from the lipopolysaccharides (LPS) of enteric Gram-negative bacilli. Differences that appear to be biologically important occur in the composition and attachment of acyl chains to lipid A, phosphorylation patterns of lipid A, and the incorporation and phosphorylation of sugar residues in the LOS inner core. Further, unlike most enteric LPS, only two to five sugar residues are attached to the meningococcal LOS inner core, and there are no multiple repeating units of O-antigens. In contrast to Escherichia coli, where the LPS biosynthesis genes are organized as large operons, the meningococcal LOS biosynthesis genes are organized into small operons or are located individually in the chromosome. Some of these genetic loci in meningococci and gonococci display polymorphisms caused by localized chromosomal rearrangements. One mechanism of antigenic variation of meningococci LOS is the regulation of glycosyltransferase activity by slipped strand mispairing of homopolymeric tracts within the 5' end of the genes encoding these enzymes, resulting in the addition of different sugar residues to the LOS molecule. Meningococcal LOS is a critical virulence factor in N. meningitidis infections and is involved in many aspects of pathogenesis, including the colonization of the human nasopharynx, survival after bloodstream invasion, and the inflammation associated with the morbidity and mortality of meningococcemia and meningitis. Meningococcal LOS, which is a component of serogroup B meningococcal vaccines currently in clinical trials, has been proposed as a candidate for a new generation of meningococcal vaccines. The rapidly expanding knowledge of the genetic basis for biosynthesis, structure, and regulation of meningococcal LOS provides insights into unique endotoxin structures and the precise role of LOS in the pathogenesis of meningococcal disease.