Meningitidis Serogroup W135 Research Articles

Meningococcal pneumonia, a case report

Background: Traditionally, Neisseria meningitidis posed significant morbidity and mortality causing epidemics or sporadic cases of meningitis or septicemia with moribund complications if untreated early. However, it has been observed rarely causing community-acquired pneumonia, without any central nervous system complications. Case Description: A 64 year old gentleman, with underlying diabetes mellitus presented with 1 week history of non-productive cough, fever and lethargy. There was no neck stiffness or headache and the immediate family members denied any altered sensorium or behavioral changes. He was well prior to admission and no recent travelling or Hajj pilgrimage. He was febrile at 38.3 C and fine bibasal crepitations noted on auscultation. Chest radiograph revealed bilateral perihilar haziness. Blood culture grew Neisseria meningitidis, identified by Vitek-2 NH and API NH systems. The antimicrobial susceptibility test showed that the isolate was susceptible to ceftriaxone, meropenem. Penicillin was intermediate with MIC of 0.094 μg/ml. The isolate was also sent to Institute of Medical Research (IMR), Kuala Lumpur which has confirmed the isolate as Neisseria meningitidis serogroup W135. The patient was treated with IV ceftriaxone for 1 week and kept in isolation room with contact precaution advised. Close contacts and laboratory personnel were offered post-exposure prophylaxis for those who had been exposed. He was subsequently discharged well. Discussion: Neisseria meningitidis is frequently associated with meningitis and meningococcal disease with severe debilitating complications. It is a fastidious gram negative diplococci, which is found in humans, as the only reservoir. It is transmissible by droplets from the nasopharynx of colonized persons. This organism commonly causes meningococcemia and acute meningitis. However, meningococcal pneumonia was being infrequently reported, partly due to low clinical suspicion and uncertainty to establish diagnosis of pneumonia. Many cases were initially misidentified hence the need for high clinical suspicion and precise laboratory identifications in suspected cases. Conclusion: Here, we reported a case of primary meningococcal pneumonia. The patient did not succumb to any neurological complications and was discharged well after one week of ceftriaxone. Thus, Neisseria meningitidis should be considered as an aetiological agent of community-accquired pneumonia especially in the elderly.

Crystallographic analysis of Neisseria meningitidis PorB extracellular loops potentially implicated in TLR2 recognition.

Among all Neisseriae species, Neisseria meningitidis and Neisseria gonorrhoeae are the only human pathogens, causative agents of bacterial meningitis and gonorrhoea, respectively. PorB, a pan-Neisseriae trimeric porin that mediates diffusive transport of essential molecules across the bacterial outer membrane, is also known to activate host innate immunity via Toll-like receptor 2 (TLR2)-mediated signaling. The molecular mechanism of PorB binding to TLR2 is not known, but it has been hypothesized that electrostatic interactions contribute to ligand/receptor binding. Strain-specific sequence variability in the surface-exposed loops of PorB which are potentially implicated in TLR2 binding, may explain the difference in TLR2-mediated cell activation in vitro by PorB homologs from the commensal Neisseriae lactamica and the pathogen N. meningitidis. Here, we report a comparative structural analysis of PorB from N. meningitidis serogroup B strain 8765 (63% sequence homology with PorB from N. meningitidis serogroup W135) and a mutant in which amino acid substitutions in the extracellular loop 7 lead to significantly reduced TLR2-dependent activity in vitro. We observe that this mutation both alters the loop conformation and causes dramatic changes of electrostatic surface charge, both of which may affect TLR2 recognition and signaling.

Synthesis of Neisseria meningitidis Serogroup W135 Capsular Oligosaccharides for Immunogenicity Comparison and Vaccine Development

Carbohydrate VaccineC.-H. Wang, S.-T. Li, T.-L. Lin, Y.-Y. Cheng,T.-H. Sun, J.-T. Wang, T.-J. R. Cheng,K. K. T. Mong, C.-H. Wong,C.-Y. Wu* &&&&—&&&&Synthesis of Neisseria meningitidisSerogroup W135 CapsularOligosaccharides for ImmunogenicityComparison and Vaccine DevelopmentSweetening the deal: N. meningitidisserogroup W135 capsular oligosacchar-ides were synthesized in lengths fromdisaccharides to decasaccharides. Serafrom mice immunized with these oligo-saccharide–protein conjugates wereexamined by a glycan microarray (seepicture) and bactericidal assay for anti-body specificity and the ability to killbacteria.

Infection by Neisseria meningitidis serogroup W135 belonging to the unusual clone ST-3342 in the Czech Republic

Infection by Neisseria meningitidis serogroup W135 belonging to the unusual clone ST-3342 in the Czech Republic

Neisseria meningitidisStrain of Unknown Serogroup, China

<i>Neisseria meningitidis</i>Strain of Unknown Serogroup, China

Molecular Discrimination between Neisseria meningitidis Serogroups W-135 and Y Based on the Nucleotide Recognition Domain Sequence of the Capsule Polymerases

Pathogenic Neisseria meningitidis isolates in most cases express one of five capsular polysaccharide-defined serogroups, i.e., A, B, C, W-135, and Y. The capsular polysaccharides of serogroups W-135 and Y are composed of repetitive disaccharide units of sialic acid linked to galactose and glucose, respectively (1). The capsule polymerases and the encoding genes synF and synG (also referred to as siaDW-135 and siaDY, respectively) are closely related (5). We recently demonstrated that a single amino acid at position 310 in the N-terminal glycosyltransferase domain of the capsule polymerases is responsible for substrate specificity toward UDP-galactose or UDP-glucose (4). Amino acid 310 is part of the EX7E motif characteristic for the nucleotide recognition domain within glycosyltransferases (6). 310P determines the serogroup W-135 capsule, and 310G determines the serogroup Y capsule. Others furthermore demonstrated that the capsule polymerase of strains that expressed a mixed galactose/glucose-sialic acid polysaccharide were associated with 310S (11). As part of disease surveillance, nonculture diagnosis is necessary in patients who received antimicrobial agents prior to admission. The DNA sequences of synF and synG provide the basis for several diagnostic assays (2, 7-10). However, most of these assays are hampered by the fact that they rely on polymorphic sites that are functionally irrelevant. Here, we describe the discrimination of serogroups W-135 and Y based on amino acid 310 within the capsule polymerases. The test was validated using 300 meningococcal isolates derived from invasive disease (n = 160), pneumonia or urethritis (n = 7), and asymptomatic carriage (n = 133). Invasive strains were obtained from the German reference laboratory for meningococci. Carriage strains were isolated during the Bavarian meningococcal carriage study (3). By slide agglutination with antisera for identification of Neisseria meningitidis W-135 and Y (Oxoid, Wesel, Germany), 87 serogroup W-135 strains and 210 serogroup Y strains were identified. Three strains reacted with both antisera. For nonculture diagnosis, a 700-bp DNA fragment was amplified from each strain (2) and the amino acid sequence of the EX7E motif was deduced from the DNA sequence of the PCR product. EX2GX4E and EX2PX4E were found in 210 of 210 serogroup Y strains and in 86 of 87 W-135 strains, respectively, without false positives (100% specificity for both motifs) (Table ​(Table1).1). In one strain, which was identified as serogroup W-135 by slide agglutination, and in the three strains (DE8946, DE9555, and DE10572) that reacted with both antisera, EX2SX4E was found. The serogroups of these strains should be reported as “W-135,” “Y,” or “mixed W-135/Y.” Of note, in an enzyme-linked immunosorbent assay (ELISA) employing monoclonal antibodies (12), DE8946, DE9555, and DE10572 reacted only with the W-135-specific reagent. Nevertheless, taking into account the recent report providing data on mixed-serogroup W-135/Y polysaccharides in some strains (11), we suggest that a component analysis is necessary to definitively resolve the composition of the capsular polysaccharides expressed by these strains. In summary, the determination of amino acid 310 of Neisseria meningitidis serogroup W-135 and Y capsule polymerases turned out to be a reliable marker with the exception of only 1.3% of strains, which harbored an ambiguous serine at this site. TABLE 1. Correlation between serogroups and the EX7E motif within the capsule polymerases of serogroup W-135 and Y meningococci

Neisseria meningitidisSerogroup W135, China

To the Editor: Neisseria meningitidis is a gram-negative bacterium found only in humans and is a major cause of serious invasive diseases. Before 2006, in the People’s Republic of China, all meningococcal diseases were caused by serogroups A, B, and C. However, there are >13 serogroups of this organism. Three cases of infection with N. meningitidis serogroup W135 were reported in China during 2006–2008. We describe these 3 meningitis patients and the N. meningitidis serogroup W135 strains isolated from these patients by genotyping methods. Patient 1, a 36-year-old man, was seen at a local hospital in Fujian Province in January 2006. He became ill while on a business trip and was given a diagnosis by culture of an N. meningitidis infection. Patient 2, a 25-year-old man, was seen in Guangdong Province in May 2007. He had not traveled outside this area in the 10 days before becoming ill. Patient 3, a 14-year-old girl, was seen in Guangxi Province in February 2008. She was a middle school student and had toured the suburbs of this province with her classmates 2 days before becoming ill. Close contacts of all 3 patients were investigated; no additional N. meningitidis infections were detected. However, N. meningitidis was isolated from a throat swab specimen obtained from the younger cousin of patient 3. N. meningitidis infection was confirmed for all 3 patients on the basis of clinical symptoms and laboratory results. All patients reported neck stiffness. Physical examinations showed Kernig signs, Brudzinski signs, and high temperatures (>38°C). Cerebrospinal fluid (CSF) samples were turbid with increased protein levels and pressure; leukocyte counts were increased (>5,000 cells/μL). CSF culture on chocolate agar grew N. meningitidis after 24 h. Isolates were identified as serogroup W135 by using specific antiserum (Remel, Lenexa, KS, USA) at provincial Centers for Disease Control and Prevention (CDC) in China and confirmed at the China CDC. Patients were treated with antimicrobial drugs and recovered fully. An isolate from the cousin of patient 3 was also identified as W135. Etest strips and broth microdilution were used for antimicrobial drug susceptibility testing for the 4 W135 isolates. All isolates were susceptible to 12 antimicrobial drugs tested, which included therapeutic and prophylaxis agents used frequently in China. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, and outer membrane protein (porA) gene variant region subtyping were used to characterize the 4 case-related W135 N. meningitidis isolates and other isolates from asymptomatic carriers. Strain {type:entrez-nucleotide,attrs:{text:R29057,term_id:1547040,term_text:R29057}}R29057 (from France) was used as a reference strain. The 4 case-related isolates showed similar PFGE patterns. These patterns were distinct from those of other W135 isolates obtained from asymptomatic carriers. Three invasive disease isolates and 1 from the close contact of patient 3 had the same multilocus sequence type (ST) and PorA subtype; all were ST11: P1.5, 2. This subtype was not detected among other tested isolates of W135 obtained from asymptomatic carriers (Technical Appendix). ST11: P1.5, 2 N. meningitidis serogroup W135 was responsible for the epidemic of W135 meningococcal disease in 2000, which was associated with the Hajj pilgrimage in Saudi Arabia (1,2). The strain related to the Hajj pilgrimage was derived from clonal expansion within the ST11 complex/ET-37 complex (3). However, no epidemiologic data showed that the 3 cases in our study were linked to the Hajj pilgrimage. Since 2000, invasive diseases caused by W135 meningococci of ST11 have been reported in Africa, Asia, and the Middle East (4). ST11 W135 infections have been reported to cause invasive disease in Taiwan during 1996–2002 and were apparently introduced into Taiwan before the Hajj pilgrimage–associated outbreak because they were genotypically distinct from the Hajj-related W135 clone (5,6). The 3 cases we report were observed in southeastern China near Taiwan (Technical Appendix), but no direct epidemiologic links are known. Because of the lack of W135 strains from Hajj pilgrimages and Taiwan in this study, we could not provide a detailed and integrated genotypic relationship between the strains in China and those of Hajj pilgrimages and Taiwan. However, we can confirm that these 3 cases were caused by strains from the same hypervirulent clone characterized as ST11: P1.5, 2. W135 strains have been isolated after vaccination with a bivalent meningococcal vaccine in Cameroon (7). In China, the bivalent meningococcal vaccine has been successfully introduced into the national expanded immunization program in response to an outbreak of N. meningitidis serogroup C during 2003–2004 (8).The 3 patients infected with W135 in our study did not receive bivalent meningococcal vaccines. W135 meningococcal disease appears to be an emerging problem that should be investigated epidemiologically. These patients highlight the need for further epidemiologic surveillance to monitor changes in the incidence of meningococcal disease caused by W135 and for improved public health disease control strategies in the future.

Cluster of Serogroup W135 Meningococci, Southeastern Florida, 2008–2009

Recently, 14 persons in southeastern Florida were identified with Neisseria meningitidis serogroup W135 invasive infections. All isolates tested had matching or near-matching pulsed-field gel electrophoresis patterns and belonged to the multilocus sequence type 11 clonal complex. The epidemiologic investigation suggested recent endemic transmission of this clonal complex in southeastern Florida.

Meningococcal carriage and immunity in western Burkina Faso, 2003

A prospective carriage and serological study was conducted in Burkina Faso during the 2003 meningitis season, which was characterized by hyperendemic Neisseria meningitidis serogroup W135 (NmW135) and serogroup A (NmA) disease. Participants were evaluated five times at monthly intervals. In the presence of moderate NmW135 carriage, we found a low prevalence of putatively protective levels of specific immunoglobulin G (IgG) and serum bactericidal antibody (SBA) against NmW135. Specific IgG concentrations and SBA titers against NmA were relatively high in this recently vaccinated population, while no NmA carriage was detected. NmW135 carriage infrequently induced protective immunity against reference or homologous strains, while natural immunity against NmW135 was frequently lost. A vaccine that is effective against W135 will be beneficial for sub-Saharan Africa.

The Rise and Fall of EpidemicNeisseria meningitidisSerogroup W135 Meningitis in Burkina Faso, 2002–2005

During the period 2001-2002, Burkina Faso reported its first meningitis epidemic due to Neisseria meningitidis (Nm) serogroup W135, prompting concerns that this serogroup would persist as a cause of epidemic disease. During the period 2002-2005, hospital- and population-based surveillances were conducted in 3 districts in Burkina Faso. Etiology was determined by culture, polymerase chain reaction (PCR), and latex agglutination. Reference laboratories determined phenotype and genotype. Of 2004 subjects who received a lumbar puncture, 265 were identified as having Nm, including 93 who had Nm serogroup A (NmA) and 146 who had Nm serogroup W135 (NmW135). Over the study period, the proportion of cases due to NmW135 decreased by >75%, primarily because of decreased occurrence among young children and in a single district. During peak epidemic months, the annualized incidence of NmW135 decreased from 146 cases to <1 case per 100,000 population. All but 2 NmW135 isolates were phenotype W135:2a:P1.5,2 (sequence type [ST]-11 clonal complex). All NmA isolates were phenotype A:4:P1-9 (ST-2859 of the ST-5 clonal complex). We identified 1 isolate from serogroup Y (ST-11 clonal complex), 1 isolate from serogroup X that was similar to strains previously associated with epidemic disease, and 1 isolate from serogroup W135 of the newly described ST-4375 complex. For unknown reasons, serogroup W135 achieved epidemic status, primarily among young children, and then largely disappeared over a short time period. The continued circulation of multiple strains with epidemic potential emphasizes the need for ongoing surveillance and the potential benefit of vaccines that are protective across serogroups.

Neisseria meningitidisSerogroups A and W‐135: Carriage and Immunity in Burkina Faso, 2003

We sought to describe Neisseria meningitidis immunity and its association with pharyngeal carriage in Burkina Faso, where N. meningitidis serogroup W-135 and serogroup A disease are hyperendemic and most of the population received polysaccharide A/C vaccine during 2002. We collected oropharyngeal swab samples from healthy residents of Bobo-Dioulasso (4-14 years old, n=238; 15-29 years old, n=250) monthly during February-June 2003; N. meningitidis isolates were analyzed using polymerase chain reaction and serogrouped using immune sera. Serum samples were collected at the first and last clinic visit and analyzed for anti-A, anti-C, anti-W-135, and anti-Y immunoglobulin G (IgG) concentrations and anti-A and anti-W-135 bactericidal titers. N. meningitidis was carried at least once by 18% of participants; this carriage included strains from serogroups W-135 (5%) and Y and X (both <1%) but not from serogroups A, B, or C. At baseline, the prevalence of putatively protective specific IgG concentrations (> or =2 microg/mL) and bactericidal titers (> or =8) was 85% and 54%, respectively, against serogroup A, and 6% and 22%, respectively, against serogroup W-135. Putatively protective anti-W-135 IgG concentrations and bactericidal titers were of short duration and were not associated with carriage. N. meningitidis serogroup W-135 strains did not induce immunity, despite their circulation. Carriage of serogroup A strains was rare despite the hyperendemic incidence of serogroup A meningitis during 2003 in Bobo-Dioulasso. A vaccine that includes serogroup W-135 antigen and eliminates serogroup A carriage is needed for sub-Saharan Africa.

Clonal Spread of Serogroup W135 Meningococcal Disease in Turkey

Six cases of Neisseria meningitidis serogroup W135 meningococcal infection have been reported in Turkey since 2003. Seven isolates recovered from four meningococcal meningitis patients and two asymptomatic carriers produced three distinct pulsed-field gel electrophoresis (PFGE) patterns. Multilocus sequence typing and antigen gene sequencing showed that five isolates were indistinguishable from ST-11 (ET-37) serogroup W135 meningococci, which were first isolated in Saudi Arabia and were responsible for the worldwide outbreak among Hajj pilgrims and their contacts in 2000. The remaining two isolates, which had related PFGE patterns, differed from each other at only one of the genetic loci characterized but were not related to the ST-11 clonal complex. None of the six individuals recalled contact with a pilgrim or had traveled on the Hajj. These six individuals exhibited no time or place relationships to each other, except for the two asymptomatic carriers, who were soldiers and served in the same military unit. These data demonstrate that serogroup W135 meningococci with different genotypes, including the Hajj epidemic strain, are endemic in Turkey.

Epidemiological patterns of meningococcal meningitis in Niger in 2003 and 2004: under the threat of N. meningitidis serogroup W135

Since the Neisseria meningitidis serogroup W135 epidemic in Burkina Faso in 2002, the neighbouring countries dread undergoing outbreaks. Niger has strongly enhanced the microbiological surveillance, especially by adding the polymerase chain reaction (PCR) assay to the national framework of the surveillance system. During the 2003 epidemic season, 8113 clinically suspected cases of meningitis were notified and nine districts of the 42 crossed the epidemic threshold, while during the 2004 season, the number of cases was 3521 and four districts notified epidemics. In 2003 and 2004, serogroup A was identified in most N. meningitidis from cerebrospinal fluid (CSF) specimens (89.7% of 759 and 87.2% of 406, respectively). Although serogroup W135 represented only 8.3% of the meningococcal meningitis in 2003 and 7.9% in 2004, and was not involved in outbreaks, it was widespread in various areas of the country. In the regions that notified epidemics, the proportion of serogroup W135 was tiny while it exceeded 40% in several non-epidemic regions. Despite the wide distribution of W135 serogroup in Niger and the fears expressed in 2001, the threat of a large epidemic caused by N. meningitidis W135 seems to have been averted in Niger so far. There is no clear indication whether this serogroup will play a lasting role in the epidemiology of meningococcal meningitis or not. As early as in the 1990s, a significant but transient increase in the incidence of N. meningitidis serogroup X was observed. Close microbiological surveillance is crucial for monitoring the threat and for identifying at the earliest the serogroups involved in epidemics.

Infection due to Neisseria meningitidis serogroup W-135

Infection due to Neisseria meningitidis serogroup W-135

Meningitis fulminante por Neisseria meningitidis serotipo W-135 y déficit de complemento

La Neisseria meningitidis serogrupo W-135 está implicada en casos aislados de meningitis aguda en nuestro país. Se describe el caso de una paciente de origen estadounidense, que ingresa por un cuadro compatible con meningitis aguda, aislándose en el cultivo de LCR N. meningitides del serotipo W-135, comprobándose posteriormente la existencia de un déficit de la fracción C1q del complemento. The Neisseria meningitidis serogroup W-135 has been involved in isolated cases of acute meningitis here in Spain. There is described the case of one American-born patient who is admitted with clinical manifestations of acute meningitis, and with N. meningitidis serotype W-135 being isolated in cerebrospinal fluid (CSF) culture. Complement fraction C1q deficiency is later verified.

Bacterial Meningitis in Burkina Faso: Surveillance Using Field-Based Polymerase Chain Reaction Testing

In addition to frequent epidemics of group A meningococcal disease, endemic bacterial meningitis due mostly to Neisseria meningitidis, pneumococcus, and Haemophilus influenzae type b is a serious problem in sub-Saharan Africa. The improved ability to identify the etiologic agent in cases of bacterial meningitis will facilitate more rapid administration of precise therapy. To describe the epidemiology of bacterial meningitis and evaluate the usefulness of field-based polymerase chain reaction (PCR) testing, we implemented population-based meningitis surveillance in Burkina Faso during 2002-2003 by use of PCR, culture, and antigen detection tests. Among persons aged 1 month to 67 years, the incidences of meningococcal meningitis, pneumococcal meningitis, and Haemophilus influenzae type b meningitis were 19 cases (n=179), 17 cases (n=162), and 7.1 cases (n=68) per 100,000 persons per year, respectively. Of the cases of meningococcal meningitis, 72% were due to N. meningitidis serogroup W135. Pneumococcal meningitis caused 61% of deaths and occurred in a seasonal pattern that was similar to that of meningococcal meningitis. Of cases of pneumococcal meningitis and N. meningitidis serogroup W135 meningitis, 71% occurred among persons >2 years of age. Most patients, regardless of the etiology of their illness and the existence of an epidemic, received short-course therapy with oily chloramphenicol. Compared with culture as the gold standard, the sensitivity and specificity of PCR in the field were high; this result was confirmed in Burkina Faso and Paris. Precise and rapid identification of etiologic agents is critical for improvement in the treatment and prevention of meningitis, and, thus, PCR should be considered for wider use in Africa. Vaccines against Streptococcus pneumoniae, N. meningitidis (including serogroup W135), and H. influenzae type b all will have a major impact on the bacterial meningitis burden. Antibiotic recommendations need to consider the importance of S. pneumoniae, even during the epidemic season.

Neisseria meningitidisSerogroup W‐135 Carriage among US Travelers to the 2001 Hajj

In 2000, a large international outbreak of meningococcal disease caused by Neisseria meningitidis serogroup W-135 was identified among pilgrims returning from the Hajj in Saudi Arabia. To assess ongoing risk, we evaluated N. meningitidis carriage among US travelers to the 2001 Hajj. Of 25 N. meningitidis isolates obtained, 15 (60%) were nongroupable and 8 (32%) were serogroup W-135 when tested by standard slide-agglutination techniques. Two additional nongroupable isolates were characterized as serogroup W-135 when tested by polymerase chain reaction. Nine of 10 serogroup W-135 isolates were indistinguishable from the Hajj-2000 clone. None of the departing, but 9 (1.3%) of the returning, pilgrims carried serogroup W-135 (P=.01); all carriers reported previous vaccination. Carriage of N. meningitidis serogroup W-135 increased significantly in pilgrims returning from the Hajj. Although the risk of disease to pilgrims appears to be low, the risk of spread to others of this pathogenic strain remains a concern.

Clinical features and outcome of pediatric Neisseria meningitidis serogroup W135 infection: a report of 5 cases.

We describe 5 pediatric cases of Neisseria meningitidis serogroup W135 infection. Infectious and/or reactive extrameningeal involvement was frequent. One patient had a persistent postmeningococcal inflammatory syndrome. Four of 5 isolates belonged to the clonal complex 37. The important risk of extrameningeal complications must be borne in mind when treating children with N. meningitidis W135 infection.

Polymerase chain reaction assay and bacterial meningitis surveillance in remote areas, Niger.

To compensate for the lack of laboratories in remote areas, the national reference laboratory for meningitis in Niger used polymerase chain reaction (PCR) to enhance the surveillance of meningitis caused by Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. PCR effectively documented the wide geographic spread of N. meningitidis serogroup W135.

Hajj-associated outbreak strain of Neisseria meningitidis serogroup W135: estimates of the attack rate in a defined population and the risk of invasive disease developing in carriers.

An outbreak of disease due to Neisseria meningitidis serogroup W135 (W135) occurred in 2000 and 2001 among pilgrims returning from the annual Islamic pilgrimage to Saudi Arabia (the Hajj) and in their contacts. For the Hajj in 2000, the attack rate of W135 disease was 25 cases per 100,000 pilgrims. After the introduction of quadrivalent meningococcal vaccine for the Hajj in 2001, no pilgrim developed W135 disease. The estimated attack rates for household contacts of returning pilgrims were 18 cases and 28 cases per 100,000 contacts for the years 2000 and 2001, respectively. On the basis of rates of transmission of W135 carriage and national epidemiological data, the risk that an unvaccinated household contact who had acquired W135 carriage would develop invasive meningococcal disease was estimated to be 1 case per 70 acquisitions. Public health policies to protect household contacts of Hajj pilgrims need to be implemented.