Emergence of W135 meningococcal meningitis in Ghana

Neisseria meningitidis serogroup W135, well known for a long time as a cause of isolated cases of meningococcal meningitis, has recently increasingly been associated with disease outbreaks of considerable magnitude. Burkina Faso was hit by W135 epidemics in the dry seasons of 2002-2004, but only four W135 meningitis cases were recorded between February 2003 and March 2004 in adjoining Ghana. This reconfirms previous findings that bottlenecks exist in the spreading of new epidemic N. meningitidis clones within the meningitis belt of sub-Saharan Africa. Of the four Ghanaian W135 meningitis patients one died and three survived, of whom one had profound neurosensory hearing loss and speech impairment. All four disease isolates were sensitive to penicillin G, chloramphenicol, ciprofloxacin and cefotaxime and had the multi-locus sequence type (ST) 11, which is the major ST of the ET-37 clonal complex. Pulsed-field gel electrophoresis (PFGE) profiles of the Ghanaian disease isolates and recent epidemic isolates from Burkina Faso were largely identical. We conducted meningococcal colonization surveys in the home communities of three of the patients and in the Kassena Nankana District located at the border to Burkina Faso. W135 carriage rates ranged between 0% and 17.5%. When three consecutive surveys were conducted in the patient community with the highest carrier rate, persistence of W135 colonization over a period of 1 year was observed. Differences in PFGE profiles of carrier isolates taken at different times in the same patient community were indicative of rapid microevolution of the W135 bacteria, emphasizing the need for innovative fine typing methods to reveal the relationship between W135 isolates.     

Outbreaks of serogroup X meningococcal meningitis in Niger 1995-2000

In the African meningitis belt, the recurrent meningococcal meningitis epidemics are generally caused by serogroup A. In the past 20 years, other serogroups have been detected, such as X or W135, which have caused sporadic cases or clusters. We report here 134 meningitis cases caused by Neisseria meningitidis serogroup X that occurred in Niamey between 1995 and 2000. They represented 3.91% of the meningococcal isolates from all CSF samples, whereas 94.4% were of serogroup A. Meningococcal meningitis cases were detected using the framework of the routine surveillance system for reportable diseases organized by the Ministry of Public Health of Niger. The strains were isolated and determined by the reference laboratory for meningitis in Niamey (CERMES) and further typed at the WHO collaborating center of the Pharo in Marseille and at the National Reference Center for the Meningococci at the Institut Pasteur. Reference laboratories in Marseille and Paris characterized 47 isolates having the antigenic formula (serogroup:serotype:sero-subtype) X:NT:P1.5. Meningitis cases due to meningococcus serogroup X did not present any clinical or epidemiological differences to those due to serogroup A. The seasonal incidence was classical; 93.3% of the cases were recorded during the dry season. The mean age of patients was 9.2 years (+/- 6 years). The sex ratio M/F was 1.3. Case fatality rate was 11.9% without any difference related to age or sex. The increasing incidence of the serogroup X was not related to the decrease of serogroup A, but seemed cyclic, and evolved independently of the recurrence of both serogroups A and C.     

ST2859 serogroup A meningococcal meningitis outbreak in Nouna Health District, Burkina Faso: a prospective study

We analysed cerebrospinal fluid samples from suspected meningitis cases in Nouna Health District, Burkina Faso, during the meningitis seasons of 2004-2006. Serogroup A ST2859 meningococci belonging to the ST5 clonal complex of subgroup III meningococci were the predominant causative agent. ST2859 bacteria were associated with focal outbreaks in the north of the district. While >10% of the population of an outbreak village carried ST2859, the population in the south of the district was predominantly colonised by serogroup Y ST4375 meningococci, which were associated with only sporadic cases of meningitis. Colonisation with the less virulent Y meningococci may interfere with the spread of the ST2859 to the south of the district, but there are concerns that this serogroup A clone may cause a third wave of subgroup III meningococcal disease in the African Meningitis Belt.     

Microheterogeneity of serogroup A (subgroup III) neisseria meningitidis during an outbreak in northern ghana

During a meningitis outbreak in the eastern subdistrict of the Kassena-Nankana District of the Upper East Region of Ghana, we analysed cerebrospinal fluid from suspected meningitis cases for the most common causative organisms. In 50 of 92 samples analysed, serogroup A Neisseria meningitidis were detected. The ages of serogroup A N. meningitidis patients ranged from 4 months to 64 years. The case fatality ratio was 20%. Coma or stupor on presentation worsened the prognosis. All serogroup A N. meningitidis isolates recovered revealed the A: 4: P1.9, 20 phenotype characteristic for the subgroup III clonal grouping. No evidence for resistance to penicillin G, chloramphenicol, cefotaxime, ciprofloxacin, rifampicin or tetracycline was found. All strains were resistant to sulphadiazine. Restriction analysis patterns of opa, iga and ingA genes were characteristic for the majority of N. meningitidis serogroup A subgroup III bacteria isolated in Africa after the 1987 epidemic in Mecca. Differences in pulsed-field gel electrophoresis patterns of NheI and SpeI digested DNA revealed microheterogeneity among the Ghanaian isolates.     

Field evaluation of rapid diagnostic tests for meningococcal meningitis in Niger

Objective  To evaluate dipstick rapid diagnostic tests (RDTs) for meningococcal meningitis in basic health facilities.
Methods  Health facility staff received a one-day training. During the meningitis season, they performed RDTs on cerebrospinal fluid (CSF) specimens from suspected cases of meningitis. A frozen aliquot of CSF was later tested using polymerase chain reaction (PCR) to establish the reference diagnosis. RDTs used in health facilities were archived to allow checking the concordance between reported diagnosis and observed results. Reported diagnosis was also compared to PCR diagnosis. A second RDT was performed on each CSF specimen at the reference laboratory.
Results  Using RDTs, health facilities reported 382 negative results (73.9%), 114 NmA (22.1%), 12 NmW135 (2.3%) and nine uninterpretable results (1.7%), the latter corresponding to the misuse of a reagent by three agents. The agreement between reported diagnosis and archived dipsticks was excellent (kappa = 0.98). The agreement between PCR diagnosis and reported RDTs results was strong (kappa = 0.82). In health facilities, the sensitivity of RDTs for N. meningitidis A was Se = 0.91. The kappa coefficient measuring the agreement between RDTs operated in the reference laboratory and RDTs operated in health facilities was κ = 0.78.
Conclusion  We confirmed that dipstick RDTs to identify N. meningitidis serogroups A, C, W135 and Y can be reliably operated by non-specialized staff in basic health facilities. RDTs proved very useful to recommend vaccination in NmA epidemics, and also to avoid vaccination in epidemics due to serogroups not included in vaccines (NmX).     

Epidemiology of meningococcal disease in southern Brazil from 1995 to 2003, and molecular characterization of Neisseria meningitidis using multilocus sequence typing

Objective  To describe the epidemiology of meningococcal disease (MD) in southern Brazil.
Methods  Retrospective cohort study among 2215 MD cases reported from 1995 to 2003 in Rio Grande do Sul (RS) State.
Results  The overall incidence fell by 50%; the case-fatality rate during this period was 22%. Even so, the incidence of MD remained high after the epidemic period ended in 1999. Together, the age groups of 1–4 years and infants accounted for 54.1% of reported cases with incidences of 11.3/100 000 and 31.3/100 000, respectively; 69.8% of cases were caused by Neisseria meningitidis serogroup B, which increased significantly. There was a significant decrease in serogroup C cases in the whole period. The phenotypes B:4,7:P1.19,15, B:15:P1.7,16 and B:NT:P1.3 caused almost 50% of all serotyped cases. Fifty-six isolates obtained from RS patients during the first non-epidemic year 2000 plus 20 isolates from other southern Brazilian states (Santa Catarina and Paraná), Denmark and France were typed by multilocus sequence typing. Twenty sequence types (STs) were identified, eight of them found only in RS. ST-33 (27%) and ST-259 (18%) were the most frequent; both belong to the ST-32/ET-5 complex. ST-259 cases showed a trend towards higher risk of fatal outcome. ST-259 isolates were not detected among geographic controls or in other studies in Brazil.
Conclusion  Our data suggest that ST-33 and ST-259 clones and the emergence of the ST-103 isolates contributed to the continued high incidence of MD in RS.     

A case of sepsis and meningitis caused by probable travel-related Neisseria meningitidis serogroup B infection: the first report of N. meningitidis ST-4893 in Japan

Herein we present a case of Neisseria meningitidis-related sepsis and meningitis in a 60-year-old woman. The N. meningitidis strain was identified as serogroup B and sequence type (ST)-4893 by multilocus sequence typing (MLST). The patient in this case had visited France prior to development of symptoms. No meningococcal isolate belonging to ST-4893 has been identified in Japan previously, whereas an ST-4893 strain from France has been reported in the MLST database. These results strongly suggest that this case is likely to have been imported from France.