Molecular epidemiology of an outbreak of meningococcal disease in a university community

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.

Meningococcal disease burden and transmission in crowded settings and mass gatherings other than Hajj/Umrah: A systematic review

BACKGROUND

Mass gatherings (MGs) such as the Hajj and Umrah pilgrimages are known to amplify the risk of invasive meningococcal disease (IMD) due to enhanced transmission of the organism between attendees. The burden of IMD at MGs other than Hajj and Umrah has not previously been quantified through a systematic review.

METHODS

A systematic search for relevant articles in PubMed and Embase was conducted using MeSH terms; this was buttressed by hand searching. Following data abstraction, a narrative synthesis was conducted to quantify the burden of IMD at MGs and identify potential risk factors and mitigation measures.

RESULTS

Thirteen studies reporting occurrence of IMD at MGs or similar crowded settings were identified. Eight studies reported cases or outbreaks in MGs of ≥1000 people; five others reported IMD in other crowded settings; all occurred between 1991 and 2015. All age groups were involved in the identified studies; however the majority of cases (∼80%) were young people aged 15-24 years. The number of affected people ranged from one to 321 cases and the overall crude estimate of incidence was calculated as 66 per 100,000 individuals. Serogroups A, C, B and W were identified, with serogroups A and C being most common. Of 450 cases of IMD reported in non-Hajj/Umrah MGs, 67 (14.9%) had fatal outcomes.

CONCLUSION

IMD outbreaks at non-Hajj/Umrah MGs are generally much smaller than Hajj-related outbreaks and affect mainly young people. Health education and vaccination should be considered for attendees of high risk non-Hajj/Umrah MGs, especially those involving adolescents and young adults.

The cost and public health burden of invasive meningococcal disease outbreaks: a systematic review

BACKGROUND

Invasive meningococcal disease (IMD) is a serious disease with a rapid onset, high mortality rate, and risk of long-term complications. Numerous reports in the literature conclude that IMD outbreaks are associated with substantial costs to society and significant burden on communities due to the cost associated with the prevention of secondary cases.

OBJECTIVE

To systematically review the literature on the costs and public health burden associated with IMD outbreaks.

METHODS

Studies were primarily identified through searching MEDLINE and EMBASE. Reports were included if they provided cost data related to the containment of an IMD outbreak after 1990 and were written in English, French, or Spanish. Costs were converted to 2010 United States dollars. Outbreaks were categorized by low-income countries (LIC) and high-income countries (HIC) based on gross domestic product per capita. Outbreak containment strategies were classified as small (e.g., targeting members of the school/institution where the outbreak occurred) or large (e.g., targeting everyone in the community).

RESULTS

Sixteen articles reporting data on 93 IMD outbreaks fulfilled the eligibility criteria and were included. The majority of outbreaks occurred in HIC. Five studies reported the use of small containment strategies including targeted vaccination and chemoprophylaxis, all occurring in HIC. The average cost per small containment strategy was $299,641 and the average cost per IMD case was $41,857. Eight studies reported large containment strategies involving widespread vaccination targeting a specific age group or community. For HIC, the average cost per large containment strategy was $579,851 and the average cost per IMD case was $55,755. In LIC, the average cost per large containment strategy was $3,407,590 and the average cost per IMD case was $2,222.

CONCLUSION

IMD outbreaks were associated with substantial costs. We found that although there were numerous reports on IMD outbreaks, data on containment costs were very limited. More research in this area is warranted.

Usefulness of pulsed-field gel electrophoresis in tracking two outbreaks of invasive meningococcal disease serogroup C in British Columbia

Two major outbreaks of invasive meningococcal disease serogroup C (IMD-C) were identified in British Columbia between 2000 and 2004. Pulsed-field gel electrophoresis (PFGE) and porA gene sequencing of all retained IMD-C isolates were used to assess correlations between genotypes and epidemiological patterns. PFGE patterns of IMD-C genotypes correlated with epidemiological patterns between 2000 and 2004 in British Columbia, and demonstrated that PFGE can identify outbreak-related cases. Both IMD-C outbreaks correlated with a respective PFGE pattern. PFGE analysis demonstrated that the 2004 British Columbia outbreak strain in men who have sex with men was closely related to the 2001 Abbotsford outbreak strain. PorA sequencing data indicated low diversity of class 1 outer membrane proteins in British Columbia, and did not correlate with epidemiological trends. There was a trend for outbreak-associated PFGE types to demonstrate higher case fatality rates.

The modern autopsy: what to do if infection is suspected

Deaths due to infectious diseases are common worldwide. The autopsy, although less frequently performed than previously, is important to our understanding of disease pathogenesis. The autopsy also provides critical information regarding potential disease outbreaks. To optimize the benefits of an autopsy, the pathologist should approach the autopsy with a well-constructed differential diagnosis that provides the framework for appropriate selection of diagnostic specimens and tests. Standard microbiologic cultures, although necessary and important, are often insufficient and must be supplemented by newer molecular methodologies.

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.

Long-term persistence of a discotheque-associated invasive Neisseria meningitidis group C strain as proven by pulsed-field gel electrophoresis and porA gene sequencing

A cluster of a Neisseria meningitidis serogroup C strain causing invasive disease was investigated. Five out of seven cases were associated with a particular discotheque. The strains were indistinguishable, as revealed by pulsed-field gel electrophoresis and sequencing of variable regions of the porA gene, but caused strikingly different clinical presentations during 5 months.

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.

Frontiers of occupational health. New vaccines, new prophylactic regimens, and management of the HIV-infected worker

New prophylactic or treatment options are available for a number of infectious diseases that may be transmitted in the health care setting. Infectious diseases that can now be prevented by vaccination of the employee include hepatitis A, pertussis, hepatitis B, and primary varicella. New prophylactic or treatment regimens are available for Neisseria meningitidis, Streptococcus pyogenes, and Bordetella pertussis; treatment of multidrug-resistant tuberculosis is also discussed. Finally, management of the HIV-infected health care worker is reviewed.