The SIGLEC14 null allele is associated with Mycobacterium tuberculosis- and BCG-induced clinical and immunologic outcomes

Humans exposed to Mycobacterium tuberculosis (Mtb) have variable susceptibility to tuberculosis (TB) and its outcomes. Siglec-5 and Siglec-14 are members of the sialic-acid binding lectin family that regulate immune responses to pathogens through inhibitory (Siglec-5) and activating (Siglec-14) domains. The SIGLEC14 coding sequence is deleted in a high proportion of individuals, placing a SIGLEC5-like gene under the expression of the SIGLEC14 promoter (the SIGLEC14 null allele) and causing expression of a Siglec-5 like protein in monocytes and macrophages. We hypothesized that the SIGLEC14 null allele was associated with Mtb replication in monocytes, T-cell responses to the BCG vaccine, and clinical susceptibility to TB. The SIGLEC14 null allele was associated with protection from TB meningitis in Vietnamese adults but not with pediatric TB in South Africa. The null allele was associated with increased IL-2 and IL-17 production following ex-vivo BCG stimulation of blood from 10 week-old South African infants vaccinated with BCG at birth. Mtb replication was increased in THP-1 cells overexpressing either Siglec-5 or Siglec-14 relative to controls. To our knowledge, this is the first study to demonstrate an association between SIGLEC expression and clinical TB, Mtb replication, or BCG-specific T-cell cytokines.

Central nervous system manifestations of tuberculosis-associated immune reconstitution inflammatory syndrome during adalimumab therapy: a case report and review of the literature

A 64-year-old neurologically asymptomatic woman with rheumatoid arthritis who was treated with the tumor necrosis factor (TNF)-α antagonist adalimumab developed disseminated tuberculosis (TB). After receiving anti-TB therapy and discontinuing adalimumab, she exhibited paradoxical worsening due to immune reconstitution inflammatory syndrome (IRIS) with the appearance of meningitis and brain tuberculomas. This case indicates that continuing anti-TNF therapy may be necessary to prevent IRIS in patients who develop TB, particularly disseminated TB, during the course of anti-TNF therapy. In addition, careful screening for central nervous system (CNS) TB should be performed prior to the initiation of therapy, as even neurologically asymptomatic patients can develop CNS manifestations of IRIS.

[A systematic review on the protective efficacy of BCG against children tuberculosis meningitis and millet tuberculosis]

OBJECTIVE

To Understand the protective efficacy of Bacillus Calmette Guerin (BCG) vacciation against children tuberculosis meningitis and millet tuberculosis, to provide the data to improve immune tactics of BCG.

METHODS

A search CHKD full text database (1979-2007) and CHKD meeting paper database (1999-2008) and WANGFANG database (1982-2007), with BCG, tuberculosis meningitis, millet tuberculosis, then to analyze information from qualified literatures.

RESULTS

28 paper were involved. 25 were correlated with tuberculosis meningitis, 1 correlated with millet tuberculosis, 2 correlated with both. The study about protections of BCG against tuberculosis meningitis showed that BCG has protective action in ecology study. The inoculation of BCG in tuberculosis meningitis cases was 0-69.08%, millet tuberculosis BCG inoculating with 82.76%. Result of Mete analysis showed that it was 81% to the protection tuberculosis meningitis, 95% CI is 57%-91%.

CONCLUSION

BCG vaccine has protective effect for preventing tuberculous meningitis. Due to lack of case-control study, cases in vaccinated and unvaccinated ratio should not an objective description of the effect of BCG vaccination. Protective effect of miliary tuberculosis research literature was less, unable to come to precise conclusions.

A multi-valent vaccinia virus-based tuberculosis vaccine molecularly adjuvanted with interleukin-15 induces robust immune responses in mice

Tuberculosis caused by Mycobacterium tuberculosis is responsible for nearly two million deaths every year globally. A single licensed vaccine derived from Mycobacterium bovis, bacille Calmette-Guerin (BCG) administered perinatally as a prophylactic vaccine has been in use for over 80 years and confers substantial protection against childhood tuberculous meningitis and miliary tuberculosis. However, the BCG vaccine is virtually ineffective against the adult pulmonary form of tuberculosis that is pivotal in the transmission of tuberculosis that has infected almost 33% of the global population. Thus, an effective vaccine to both prevent tuberculosis and reduce its transmission is urgently needed. We have generated a multi-valent, vectored vaccine candidate utilizing the modified virus Ankara (MVA) strain of vaccinia virus to tandemly express five antigens, ESAT6, Ag85A, Ag85B, HSP65 and Mtb39A of M. tuberculosis that have been reported to be protective individually in certain animal models together with an immunostimulatory cytokine interleukin-15 (MVA/IL-15/5Mtb). Although, immunological correlates of protection against tuberculosis in humans remain to be established, we demonstrate that our vaccine induced comparable CD4(+) T cell and greater CD8(+) T cell and antibody responses against M. tuberculosis in vaccinated mice in a direct comparison with the BCG vaccine and conferred protection against an aerogenic challenge of M. tuberculosis, thus warranting its further preclinical development.

BCG vaccine: efficacy and indications for vaccination and revaccination

OBJECTIVES

To review the protective efficacy of the first and second doses of BCG vaccine and to assess its major indications and contraindications.

SOURCES OF DATA

A systematic review of the literature was made by searching PubMed and selecting studies carried out in the last 50 years. The studies were grouped according to their design (clinical trials, case-control studies, and meta-analyses) and the results were presented separately for each type of study. Other relevant topics such as BCG and HIV/AIDS, use of tuberculin skin test, issues related to vaccine scars and to the development of new vaccines were also reviewed.

SUMMARY OF THE FINDINGS

BCG vaccine has been used since 1921. However, the data concerning its use are variable and inconsistent. The protective efficacy of the first dose of BCG vaccine against miliary tuberculosis or tuberculous meningitis is remarkably important. Nevertheless, results regarding pulmonary tuberculosis have been inconsistent, either showing no efficacy or a protective efficacy rate around 80%. There is some evidence that a second dose of BCG vaccine does not increase its protective efficacy. Studies have shown that BCG vaccine protects against leprosy. The development of new vaccines to replace BCG in the future has been investigated.

CONCLUSIONS

Despite the hope that a new vaccine against tuberculosis will be available in the future, BCG vaccine, in spite of its deficiencies, is today and will be for many years to come an important tool in controlling the harmful effects of tuberculosis, especially in countries where this disease has moderate to high levels of incidence.

Evaluation of the Mtb72F polyprotein vaccine in a rabbit model of tuberculous meningitis

Using a rabbit model of tuberculous meningitis, we evaluated the protective efficacy of vaccination with the recombinant polyprotein Mtb72F, which is formulated in two alternative adjuvants, AS02A and AS01B, and compared this to vaccination with Mycobacterium bovis bacillus Calmette-Guérin (BCG) alone or as a BCG prime/Mtb72F-boost regimen. Vaccination with Mtb72F formulated in AS02A (Mtb72F+AS02A) or Mtb72F formulated in AS01B (Mtb72F+AS01B) was protective against central nervous system (CNS) challenge with Mycobacterium tuberculosis H37Rv to an extent comparable to that of vaccination with BCG. Similar accelerated clearances of bacilli from the cerebrospinal fluid, reduced leukocytosis, and less pathology of the brain and lungs were noted. Weight loss of infected rabbits was less extensive for Mtb72F+AS02A-vaccinated rabbits. In addition, protection against M. tuberculosis H37Rv CNS infection afforded by BCG/Mtb72F in a prime-boost strategy was similar to that by BCG alone. Interestingly, Mtb72F+AS01B induced better protection against leukocytosis and weight loss, suggesting that the polyprotein in this adjuvant may boost immunity without exacerbating inflammation in previously BCG-vaccinated individuals.

Effect of BCG vaccination on childhood tuberculous meningitis and miliary tuberculosis worldwide: a meta-analysis and assessment of cost-effectiveness

BACKGROUND

BCG vaccine has shown consistently high efficacy against childhood tuberculous meningitis and miliary tuberculosis, but variable efficacy against adult pulmonary tuberculosis and other mycobacterial diseases. We assess and compare the costs and effects of BCG as an intervention against severe childhood tuberculosis in different regions of the world.

METHODS

We calculated the number of tuberculous meningitis and miliary tuberculosis cases that have been and will be prevented in all children born in 2002, by combining estimates of the annual risk of tuberculosis infection, the proportion of infections that lead to either of these diseases in unvaccinated children, the number of children vaccinated, and BCG efficacy.

FINDINGS

We estimated that the 100.5 million BCG vaccinations given to infants in 2002 will have prevented 29,729 cases of tuberculous meningitis (5th-95th centiles, 24,063-36,192) in children during their first 5 years of life, or one case for every 3435 vaccinations (2771-4177), and 11,486 cases of miliary tuberculosis (7304-16,280), or one case for every 9314 vaccinations (6172-13,729). The numbers of cases prevented would be highest in South East Asia (46%), sub-Saharan Africa (27%), the western Pacific region (15%), and where the risk of tuberculosis infection and vaccine coverage are also highest. At US2-3 dollars per dose, BCG vaccination costs US206 dollars (150-272) per year of healthy life gained.

INTERPRETATION

BCG vaccination is a highly cost-effective intervention against severe childhood tuberculosis; it should be retained in high-incidence countries as a strategy to supplement the chemotherapy of active tuberculosis.

[Tuberculous meningitis in children under 5 years of age in Argentina]

Tuberculous (TB) meningitis in children under 5 years of age is a serious health problem in Argentina, with a rate of 0.39/100000 inhabitants, for 2003-2004. This rate indicates recent infections. It is an operational indicator for case finding and treatment of pulmonary adult cases, and for BCG vaccination of the newborn. The object of this study was to describe epidemic and clinical variables registered in cases of TB meningitis in children less than 5 years old in Argentina, from 1999 to 2001 and to determine the real number of TB meningitis cases in our country. Fifteen cases of TB meningitis out of 32 (46.8%) were studied through epidemic records. The average age was 14 months. Six children presented BCG scars but in only one child it was proved that he had been vaccinated at birth; 11/13 (92.3%) were at the second stage of illness, the bacteriological investigation was positive in 8/11 (72.7%) and in (46.8%) chest radiography revealed abnormal findings. The tuberculin reaction was negative in all tested cases. This study showed that the diagnosis was made at an advanced stage of disease. None of these patients was cured without sequels and a high death rate (46%) was observed. In order to control this epidemic situation, it is necessary to increase case finding and directly observed treatment of smear positive pulmonary TB cases, as well as BCG vaccination given at birth.

Tuberculous meningitis in BCG vaccinated and unvaccinated children

BACKGROUND

A modified clinical presentation of tuberculous meningitis (TBM) in children vaccinated with BCG has been described in the literature. However, most reports are old and not based on actual comparisons and tests of significance. Also, neuroimaging features were not compared. With large scale BCG coverage, it becomes pertinent to describe the "modified" presentation and identify any significant differences between vaccinated and unvaccinated children with TBM.

METHODS

A total of 150 consecutive hospitalised children (96 unvaccinated, 54 vaccinated) were enrolled. They all satisfied predefined criteria for diagnosis of TBM. Clinical and radiological features of children with/without a BCG scar were compared.

RESULTS

Univariate analysis revealed that the vaccinated children with TBM had significantly lower rates of altered sensorium (68.5% v 85.4% unvaccinated; OR 2.2 (1.1 to 6.2); p = 0.019) and focal neurological deficits (20.3% v 39.5% unvaccinated; OR 2.6 (1.1 to 6.0); p = 0.016), and higher mean (SD) Glasgow Coma Scale score (10.2 (3.4) v 8.76 (2.7) unvaccinated; p = 0.010) and cerebrospinal fluid cell count (210.9 v 140.9 unvaccinated; p = 0.019). No significant radiological differences were seen. Short term outcome was significantly better in the vaccinated group with 70% of the total severe sequelae and 75% of the total deaths occurring in the unvaccinated group (p = 0.018).

CONCLUSION

Children with TBM who have been vaccinated with BCG appear to maintain better mentation and have a superior outcome. This may in part be explained by the better immune response to infection, as reflected in the higher CSF cell counts in this group in the present study.

[Evaluating 82 cases of tuberculous meningitis]

Tuberculous meningitis (TBM) is not the most common but the most serious clinical form of extrapulmonary tuberculosis. Serious complications resulting from difficulties in diagnosis and treatment of the disease makes it an important health problem. In our study, 82 patients with TBM, followed up in our clinic between January 1998-December 2002, are evaluated with their clinical and laboratory properties. 52% of our patients were females, 48% were males and their ages ranged from 15 to 70 with a mean of 32 years. The diagnosis was based on patients' history, clinical and laboratory properties, cerebrospinal fluid (CSF) findings and radiographic findings. 59% of our patients were grade II clinically, 29% were grade I, and 23% were grade III. Mostly observed complaints were headache (87%) and nausea-vomiting (63%) and fever (45%) and mostly seen physical findings were stiff neck (70%), alterations in consciousness (57%). Pleocytosis in CSF was detected in 94%, low CSF glucose level in 87%, and elevated CSF protein level in 82% of the patients. From CSF samples of 40 patients, out of total 82, Mycobacterium tuberculosis was isolated on Loewenstein-Jensen medium (49%). Nineteen patients had tuberculomas, 13 had basal meningitis, and 11 had hydrocephalus on cranial radiographic studies. 28% had miliary pattern and 26% had active infiltration and cavities on chest roentgenogram. A four-drug antituberculous regimen was administered for 88% of the patients and dexamethasone treatment was administered for 75%; 56 (68.3%) patients recovered from the illness, 14 (17%) patients had slight and 4 (4.9%) patients had serious neurological sequeales and 8 (9.8%) patients died in spite of tuberculous therapy. As a conclusion, TBM is an infectious disease with high morbidity and mortality rates. Various prognosis patterns may be observed according to the clinical grade of the patient on application. When suspected, an early diagnosis and early treatment of the disease are the most important factors which effect complication and mortality rates.

Protective role of BCG vaccination against tuberculous meningitis in Indian children: a reappraisal

BACKGROUND

The protective role of BCG vaccination against tuberculous meningitis (TBM) is still controversial in India, largely due to the presence of other predisposing factors such as age, nutritional and socioeconomic status, and household contact. Very few Indian studies have focused on the interaction between BCG and these factors on the occurrence of TBM.

METHODS

We did an unmatched hospital-based case-control study with prospective enrolment. Children with TBM diagnosed on the basis of predefined criteria were enrolled as cases. For each case, two children admitted on the same day and who did not have any neurological symptoms were enrolled as controls. Demographic data and information on predisposing factors for tuberculosis were collected for both cases and controls and the presence of a BCG scar was charted. Cases and controls were compared by univariate followed by multivariate analysis to obtain significant independent predictors for the occurrence of TBM. To assess the interaction between other predisposing factors and protective efficacy of BCG, a stratified analysis was also done.

RESULTS

A total of 91 cases and 182 controls were enrolled over a one-year study period, of which 37 cases and 111 controls had a BCG scar. The crude odds ratio for the occurrence of TBM in the absence of a BCG scar was 2.28 (range: 1.32-3.94). The time elapsed since vaccination was significantly longer in the cases. Also, the proportion with a household contact was significantly higher in the cases, the mean age of the cases was higher than that of the controls, and the mean weight and height for age percentage were significantly lower. The cases had a significantly lower socioeconomic status. On multivariate analysis, the significant independent predictors for the occurrence of TBM were positive household contact with tuberculosis (adjusted OR 4.26; 95% CCI 2.26-8.04), absent BCG scar (adjusted OR 1.98; 95%ClI 1.09-3.57) and rural residence (adjusted OR 2.07; 95% ClI 1.02-4.17).

CONCLUSION

Vaccination with BCG was found to be protective even after controlling for the effect of other variables. Stratified analysis showed that protection due to BCG failed to reach significance for those > 5 years of age, if the weight was <6 0% of that expected for age, in the presence of a household contact with tuberculosis, and in socioeconomic classes III, IV and V.

Bacterial meningitis and encephalitis in ruminants

The clinical aspects of bacterial meningitis in neonates are described in this article. Specific types of meningitis affecting adult cattle are also described. Other conditions occurring less frequently,such as frontal sinusitis and brain abscess, are discussed.

Protective effect of neonatal BCG vaccines against tuberculous meningitis

Neonatal BCG vaccination reduces the risk of tuberculosis and provides protection higher than 80% against the development of meningeal and miliary tuberculosis in newborns. Tuberculosis meningitis remains a major problem and also an important cause of death in some countries. In countries with high and moderate incidence of tuberculosis, prevention from the most severe complications of tuberculosis can be achieved only with a high coverage of the universal BCG neonatal immunization, being higher than 98% in the cohort of newborns. The decrease in BCG immunization coverage within immunization program during the year 2003 in Bosnia and Herzegovina influenced the increase in tuberculous meningitis. During 2002, when coverage with BCG vaccination in cohort of newborns was 90%, the incidence rate of tuberculous meningitis was 19. 04%oo. With the 68% decrease in BCG immunization coverage in the cohort of newborns in Bosnia and Herzegovina during the year 2003, the incidence of tuberculous meningitis raised to 33 33%oo. It has been proven that the 22% decrease of the neonatal BCG immunization coverage in the cohort of newborns /vaccination program of children/ caused 175 times higher number of the tuberculous meningitis cases. Newborns affected by the tuberculous meningitis were not BCG vaccinated. BCG vaccine provided effective protection against tuberculous meningitis, as well against the death of newborns caused by tuberculosis.

[Epidemiology of bacterial meningitis in France in 1999]

In France, two sources of data, the mandatory notification and the laboratory network EPIBAC, allow the health authorities to follow the incidence of bacterial meningitis (BM) and to assess the relative frequency of the micro-organisms responsible for such infection. In 1999, more than 1,000 cases of BM were notified in France. The more common micro-organisms were: Streptococcus pneumoniae 46%, Neisseria meningitidis 32% and Streptococcus agalactiae(or Streptococcus B) 11%. Listeria monocytogenes and Haemophilus influenzae accounted for 6% and 5% of the cases respectively. In 1999, the incidence per 100,000 inhabitants of meningitis due to pneumococci (0.81), to streptococci B (0.19) and tuberculosis meningitis (0.17) were stable since 1995. The incidence rate of meningitis due to Listeria (0.10) and to H. influenzae (0.08) shows a regular decrease since 1992. The impact of preventive measures of meningitis due to Listeria and H. influenzae B has been clearly demonstrated through the dramatic decrease of meningitis due to these micro-organisms.

[Tuberculous meningitis in infants]

Tuberculous meningitis (TM) develops more frequently in unvaccinated or inadequately vaccinated infants (28 cases of 34), in contact infants (26 of 34 cases). Within the first year of life TM is especially aggressive. Late diagnosis and treatment leave significant residual neurological changes or result in lethal outcomes.

The impact of directly-observed treatment on the epidemiology of tuberculosis in Beijing

SETTING

Fully supervised chemotherapy, or directly observed treatment (DOT), for newly detected smear-positive cases in Beijing, has been successfully implemented for two decades.

OBJECTIVE

To evaluate the progress made in tuberculosis control, and in particular to evaluate the impact of DOT on tuberculosis epidemiology in Beijing.

DESIGN

Epidemiological parameters on tuberculosis, consisting of mortality, prevalence, notification rate, tuberculous meningitis in children and initial drug resistance rate, were collected and analysed. Their trends were evaluated and compared with DOT implemented for new smear-positive cases in Beijing from 1978 to 1996.

RESULTS

The coverage of DOT for new smear-positive pulmonary tuberculosis cases has increased from 10% in 1978 to more than 90% since 1990. Since DOT was introduced in 1978, mortality from tuberculosis has declined by an average of more than 7% per year. The reduction rate of 17.2%, and the rates of chronic cases and tuberculous meningitis in children decreased dramatically. The rate of newly registered smear-positive cases decreased from 18.9/100000 in 1986 to 7.3/100000 in 1996, giving an average annual reduction rate of 9.1 during this period. Initial resistance to isoniazid and streptomycin decreased from respectively 13.9% and 12.3% in 1978-1979 to 4.2% and 5.8% by 1996. The level of multidrug resistance was low and stable, at 0.8% in 1996.

CONCLUSION

The experience of the Beijing tuberculosis control programme convincingly demonstrates that it is possible to improve the epidemiological situation rapidly in a low-income country, at very low cost and in a manner that is self-sufficient and sustainable.

Risk of tuberculosis infection and tuberculous meningitis after discontinuation of Bacillus Calmette-Guerin in Beijing

In Beijing, the notification rate of smear-positive tuberculosis (TB) has been below 20 per 100,000 since 1986, and continues to decline. To accurately measure the risk of TB infection in a population in which the results of tuberculin skin testing were not confounded by vaccination with Bacillus Calmette-Guerin (BCG), BCG vaccination at birth was discontinued from 1988 in Shun-yi County. In 1995, the prevalence of TB infection among 12,836 primary school children aged 6 to 7 yr and without BCG scars was 1.4%, giving an estimated annual risk of infection of 0.19% (95% confidence interval: 0.16 to 0.22%). The prevalence of TB infection in children aged 5 to 9 yr in Beijing in 1950 was 46%. The number of cases of tuberculous meningitis did not increase after discontinuation of BCG. We conclude that discontinuation of BCG had no detectable harmful effects, and that control of TB in Beijing has markedly reduced the prevalence of TB infection since 1950.

Tuberculous meningitis in a Filipino maid

Tuberculous meningitis, while not uncommon in Taiwan, has not been reported among foreign workers. We report the first case of tuberculous meningitis in a 37-year-old Filipino maid in Taiwan, who presented with headache, fever and vomiting. She had been well before this episode and the small screening films of the chest radiograph obtained on her arrival in Taiwan 15 months previously, and every 6 months thereafter showed no evidence of tuberculosis. The suspicion of tuberculous meningitis was delayed until disturbance of consciousness manifested and a standard chest radiograph showed a diffuse miliary pattern in both lung fields. A cerebrospinal fluid sample that was sent for a polymerase chain reaction-based assay specific for Mycobacterium tuberculosis showed a positive result. The patient recovered with sequelae of mildly incoherent speech and urinary incontinence after antituberculous medication and short-course steroid treatment. Clinicians should be aware of the possibility of tuberculous meningitis in foreign workers with complaints of fever and headache. Because high-quality chest radiographs are a prerequisite for early detection of pulmonary tuberculosis, we recommended that standard posterior-anterior chest radiographs should be obtained as part of the routine health examination for foreign workers.

Effectiveness of BCG vaccination against tuberculous meningitis

OBJECTIVE

To assess the protective effectiveness of BCG vaccination against tuberculous meningitis, while controlling for age, nutrition and socio-economic status, in children 1 month to 12 years of age.

DESIGN

Case-control study.

SETTING

Secondary care referral and teaching hospital.

METHODS

Cases were those conforming to the definition of tuberculous meningitis and controls were patients admitted after every third consecutive case included in the study from September 1995 till the end of August 1997 and who did not suffer from any central nervous system disorder.

RESULTS

Among the 192 cases and 70 controls, BCG scar was present in 57.8% and 75.7%, respectively. The crude odd's ratio (OR)for tuberculosis meningitis with a BCG scar was 0.44 (95% CI, .24-0.81; p = 0.008), while the adjusted OR was 0.53 (95% CI, 0.26-1.06; p value = 0.07) after controlling for weight, age, sex and place of residence. Higher weight for age and urban residence were associated with a decreased risk of tuberculous meningitis in the logistic model.

CONCLUSIONS

BCG vaccination offers protection against tuberculous meningitis. Since improvement in weight for age was associated with a decreased risk of disease, further studies are needed to evaluate the association, if any, between nutritional status and vaccine efficacy.

The effect of prior BCG vaccination on the clinical and radiographic presentation of tuberculosis meningitis in children in Istanbul, Turkey

SETTING

Department of Pediatrics, Istanbul University Faculty of Medicine, Istanbul, Turkey, between January 1984 and December 1996.

OBJECTIVE

To explore whether neonatal BCG vaccination offers any protective effect on clinical and laboratory profiles of central nervous system (CNS) tuberculosis in children.

DESIGN

A retrospective review of cases of CNS tuberculosis diagnosed and treated in one institution.

RESULTS

Of the 145 patients identified with CNS tuberculosis, 9.6% were vaccinated during the neonatal period. The rate of close contact with contagious pulmonary tuberculosis in family, age distribution, clinical findings and laboratory investigations on admission were not significantly different in vaccinated and non-vaccinated children. Although mortality rate in the vaccinated patients (8.3%) was found to be nearly half of that in the non-vaccinated group (15.1%), severe sequelae were significantly more frequent (P < 0.02) among the vaccinated patients;

CONCLUSION

This study shows that neonatal BCG vaccine has little effect on the clinical findings of subsequent CNS tuberculosis, and that these children have typical presentations of tuberculosis disease.

[A preventable case who died of miliary tuberculosis after receiving contact examination]

A 30-year-old-man was admitted to our hospital because of headache and fever. His consciousness on admission was clouding. Sputum examination was positive for acid fast bacilli which later identified as Mycobacterium tuberculosis. Chest-X-ray and computed tomogram on admission showed multiple cavitary lesions on bilateral upper lung fields and bilateral diffuse nodular shadow. He was diagnosed as miliary tuberculosis with tuberculous meningitis. His mother admitted because of pulmonary tuberculosis four months ago, and her sputum examination was smear positive for acid fast bacilli, Gaffky 4, and she complained of cough for 6 months before admission. Because of this situation, he rapidly underwent the contact examination with chest X-ray, but not examined by tuberculin skin test because he was 30-year-old. As then chest X-ray was normal, he was not indicated of chemoprophylaxis, and he died of miliary tuberculosis and tuberculous meningitis 4 months after the contact examination.

The annual risk of infection with Mycobacterium tuberculosis in England and Wales since 1901

SETTING

England and Wales.

OBJECTIVE

To estimate the magnitude and trend in the annual risk of infection with Mycobacterium tuberculosis in England and Wales since 1901.

DESIGN

Estimates for the prechemotherapy era are derived assuming that 1% of new infections among 0-4 year olds led to fatal tuberculosis meningitis, as found in the Netherlands. The estimates are validated against data from the 1949-1950 national tuberculin survey. We explore the trend thereafter using tuberculous meningitis notifications and data from the 1971-1973 national tuberculin survey, and discuss the utility of data collected under the national bacille Calmette-Guérin (BCG) vaccination scheme for estimating the annual risk of infection.

RESULTS

Tuberculosis meningitis mortality rates among 0-4 year olds declined at 4% per annum until 1950, and suggest that the annual risk of infection declined from 12% in 1901 to 1.9% in 1949. The decline in the annual risk of infection probably accelerated in 1950, although its magnitude cannot be determined accurately.

CONCLUSION

An accelerated decline in the annual risk of infection in England and Wales from 1950 probably resulted from the introduction of chemotherapy, which dramatically reduced the prevalence of sources of infection in the population. Data collected during the national BCG vaccination scheme were found to be unsuitable for estimating infection risks.

Use of DNA fingerprinting in international source case finding during a large outbreak of tuberculosis in The Netherlands

SETTING

Tuberculosis outbreak in a low prevalence country.

OBJECTIVE

Description of an international source tracing process in which restriction fragment length polymorphism (RFLP) analysis played an essential role.

DESIGN

In 1993 a large scale source tracing process was initiated in Harlingen, a harbour town in the north of The Netherlands, after a child with tuberculous meningitis was reported for which no source could be identified. Traditional contact tracing followed the detection of sources of infection. RFLP was used to map the tuberculosis transmission and identify the source case.

RESULTS

The investigation extended from the north to several places in the west of The Netherlands. In total 6519 persons were screened; there were 276 infections, among which 49 cases of active tuberculosis were identified. RFLP analysis of Mycobacterium tuberculosis isolates from all 28 culture positive patients showed the 'Harlingen' type DNA fingerprint. After 5 months source tracing led to the identification of the source case in the United Kingdom. Up to June 1996 altogether 37 patients (The Netherlands 28; the UK 7; Surinam 1; Morocco 1) were found to have isolates with the Harlingen type DNA pattern. Despite a thorough evaluation, in 5 of the 37 patients no relation to the source case or the outbreak in Harlingen could be established.

CONCLUSION

RFLP typing proved a very useful instrument in guiding the process of international source tracing and contact investigation.

[Epidemic trend of tuberculous meningitis in children of Heilongjiang province]

OBJECTIVE

To investigate the epidemic trend of tuberculous meningitis in children of Heilongjiang province in recent ten years, and to provide scientific evidence for control of the disease.

METHODS

The data, registered by 82 counties' antituberculosis institute, of tuberculous meningitis patients under 14 years were analyzed, and the epidemic trend of the disease was also discussed.

RESULTS

The incidence of tuberculous meningitis was 9.58 per 10,0000 populations in 1982, 2.17 per 10,0000 populations in 1992. The rate of annual decrease was 13.8%.

CONCLUSION

Participation of the government, improvement of pelple's life standard, control of sources of infection, and vaccination of BCG are effective measures for decreasing the incidence of this disease.

Does B.C.G. vaccination prevent or postpone the occurrence of tuberculous meningitis?

The reported efficiency of B.C.G. vaccine in prevention of primary childhood or sputum positive adult tuberculosis vary widely but it is believed to offer significant protection against hematogenous forms of tuberculosis. The present hospital-based, case control study was aimed at evaluation of impact of B.C.G. vaccination on one of the hematogenous forms of tuberculosis i.e. Tuberculous meningitis (TBM). Records of cases of TBM admitted in the pediatric wards of Lok Nayak Hospital, Delhi, over one year were analyzed retrospectively for B.C.G. positivity status and age distribution. The results were compared with similar data obtained from a control group comprising of non-TBM cases in pediatric wards of same hospital, recruited on 2 days, separated by an interval of three weeks. No statistically significant difference was found in B.C.G. positivity status of cases and control groups. However, there was an obvious trend in age distribution among cases of TBM with respect to the B.C.G. status, with a significantly higher proportion of B.C.G. vaccinated children in over 5-year age group, as compared to those in under 5 year age group. The results, therefore, indicate probable effectiveness of B.C.G. against TBM only for a limited duration i.e. single B.C.G. immunization only postpones rather than prevent the occurrence of TBM.

Does BCG vaccine prevent tuberculous meningitis?

The reported efficacy of BCG vaccine in preventing pulmonary tuberculosis varies from 0-80%; however, its efficacy in preventing tuberculous meningitis ranges from 52%-84%. A case-control study was conducted to assess the efficacy of BCG in preventing tuberculous meningitis in children. New cases of tuberculous meningitis, confirmed bacteriologically, were registered as cases. Controls were children suffering from febrile convulsions attending the same hospital. A total of 107 cases and 321 controls, block matched for age, were registered. Vaccination status was determined from the history reported by the mother and by BCG scar reading. Data regarding socioeconomic status, crowding, and nutritional status were collected. Using multiple logistic regression analysis the odds ratio obtained for the presence of BCG scar was 0.23 (95% confidence interval (CI) 0.14 to 0.37) and the protective efficacy of BCG vaccine in preventing tuberculous meningitis in children was found to be 77% (95% CI 71 to 83%).

Serological diagnosis of tuberculosis

The past decade has seen dramatic developments in serological tests for tuberculosis. The long history of serological tests for tuberculosis is a testimony to the need for a sensitive diagnostic test, especially when the sputum smear is unhelpful. New reagents, both purified antigens and monoclonal antibodies, provide the means to obtain a sensitivity and specificity to rival the tuberculin skin test and equal other commonly used diagnostic blood tests. Evaluation with sera from patients with smear-positive pulmonary tuberculosis has identified one antigen (antigen 5, the 38 kDa antigen) as a potential screening reagent for infectious tuberculosis and another (16 kDa antigen) for monitoring compliance. A monoclonal antibody competition assay anti-38 kDa antibody is the most sensitive serological test for smear-negative tuberculosis so far. Tests for tuberculous meningitis need clinical evaluation. Serological tests for human immunodeficiency virus (HIV)-related tuberculosis are disappointing. In general, antibody levels in primary tuberculosis are low and appear directed towards cytoplasmic antigens, whilst in post-primary disease antibody levels are higher and appear to bind to secreted antigens. No single reagent gives a 100% sensitivity; future research should identify the best combination of antigens for the serodiagnosis of tuberculosis.

Central nervous system infections in children (bacterial, tubercular)

Central nervous system infections are an important cause of childhood morbidity and mortality. This review discusses recent developments in diagnostic tests, management strategies, and prevention of bacterial and tubercular meningitis.

BCG vaccination status of children with tuberculous meningitis and the use of unsupervised isoniazid prophylaxis

From 1985 to 1992, 193 children with tuberculous meningitis (TBM) with a median age of 26 months were admitted to the Department of Paediatrics and Child Health, Tygerberg Hospital. Of these children 143 (74%) were documented to have received BCG, either by reference to 'Road to Health' cards or by contact with local authority clinic staff. In a further 18 children a BCG scar was visible. Therefore at least 161 of the children (83%) had received BCG vaccination. As the Western Cape has also been shown to have the highest incidence of TBM in South Africa, there is concern that BCG as currently used does not have a significant protective effect against disseminated tuberculosis. Seventy-seven children (40%) were also reported to have a close household contact who had been treated for pulmonary tuberculosis within the previous 24 months. Only 17 of these children (22%), however, were prescribed prophylactic isoniazid and only 7 of these completed 3 months or more prophylaxis.

Tuberculous meningitis in France in 1990: characteristics and impact of BCG vaccination

SETTING

France, 1990.

OBJECTIVE

To measure the incidence and describe the characteristics of bacteriologically-confirmed tuberculous meningitis (TBM) and to estimate the protective efficacy of BCG vaccination in children aged less than 5 years.

DESIGN

An active surveillance of TBM cases confirmed by positive cerebrospinal fluid (CSF) culture was conducted through a network of microbiology laboratories serving 99.8% of regional and district general hospitals and other large private hospitals.

RESULTS

A total of 70 cases were reported: 61% were adults over 44 years, 64% were males and 77% were born in France. 7 patients were known to be infected with HIV. 6 cases were observed in children aged less than 5 years, 2 of whom had been vaccinated with BCG. 3 of the 6 children died (one had been BCG-vaccinated). Given the 80% coverage of BCG in this age group, the protective efficacy of BCG vaccination was estimated to be 87.5% (95% CI: 30-98), which indicates that 14 TBM cases may have been prevented by BCG vaccination in 1990.

CONCLUSION

Results are consistent with the number of TBM cases expected on the basis of a 0.04% annual risk of infection. Current BCG vaccination policy in France still has a measurable impact on the incidence of tuberculous meningitis in children under 5 years of age. Given the probable continuous decrease of the annual risk of infection in future years, alternative policies should be considered.

Protective effect of BCG against tuberculous meningitis and miliary tuberculosis: a meta-analysis

The protective effect of BCG against tuberculosis (TB) estimated in randomized controlled trials and observational studies ranges from negative to close to a 100%. One of the many explanations offered for this is that different immunological mechanisms may be associated with protective effect against different forms and sites of disease. In this investigation, we recalculated vaccine protective effect separately for pulmonary disease and for meningeal/miliary disease in randomized controlled trials and case-control studies, tested for heterogeneity in site-specific estimates of protective effect and calculated a summary measure when appropriate. We found protective effect against pulmonary disease to be heterogeneous to a statistically significant degree, and thus we did not calculate a summary measure of protection. Protective effect against meningeal and miliary TB was higher than against pulmonary disease and, except for a single study with two cases only, appeared to be homogenous. Summary BCG protective effect against miliary or meningeal TB in randomized controlled trials was 86% (95% confidence interval [CI] 65, 95) and in case-control studies 75% (95% CI: 61, 84). The fact that protective effect appeared to be homogeneous against meningitis and miliary TB but not against pulmonary disease may result from the fact that patients with meningitis are on average younger and thus less likely to have been exposed to atypical bacteria; to a waning of the protective effect of BCG; or from the diversity of mechanisms of pathogenesis of pulmonary disease, which can originate from reinfection, reactivation or primary progression.

Case series evaluation of BCG vaccine efficacy against tubercular meningitis in children in Delhi

Tubercular meningitis (TBM) is a very serious disease of childhood. BCG vaccination under Universal Immunisation Programme is the only available way of preventing this disease. The present series using case-control method, evaluated efficacy of BCG against TBM in children to be 57 per cent. Suggestion has been made to initiate TBM surveillance in children and conduct multicentric prospective case-control study of similar type.

Methodological considerations in case-control studies to evaluate BCG vaccine effectiveness

Several case-control studies evaluating the effectiveness of BCG vaccine in the last decade have presented contradictory results like previous prospective studies. Methodological differences could explain some of the case-control study results. This study explores the possibility that contradictory results could be imputed to the choice of different series of controls. Three controls were compared for each case of tuberculous meningitis: neighbourhood, hospital and household. BCG effectiveness estimates were 86.8%, 92.0% and 29.5%, respectively. The data indicated an interaction between BCG vaccine status and tuberculous focus. This could have influenced the lower effectiveness estimates found when cases were compared with household controls. The paper discusses aspects related to case-control studies applied to evaluate BCG effectiveness such as: incubation period and sufficient time since vaccination to allow development of an immune response; the presence of a tuberculous focus among the groups of cases and controls and the interaction between focus and BCG vaccination; recall bias; and optimum selection of controls in case-control studies in the context of infectious diseases.

Comparison of children and adults with tuberculous meningitis in Elaziğ, Turkey

Retrospective evaluation of 16 cases of tuberculous meningitis revealed that BCG vaccination and tuberculin positivity were rare in pediatric as well as adult patients. Children with disease had developmental retardation and a high rate of maternal illiteracy as compared to normal controls.

[Study on BCG vaccination and incidence of children's tuberculous meningitis in Liaoning province]

The purpose of this study was to assess the effect of BCG vaccination on the incidence of tuberculous meningitis in children. A retrospective review was undertaken to find out vaccination rate of BCG and positive conversion mantoux rate in newborn infants. The results obtained were as follow: in 1980, vaccination rate was 51.61%, and the positive conversion Mantoux rate was 87.86%; in 1988 vaccination rate was 96.06%, and the positive conversion Mantoux rate was 94.92%. With the increase vaccination rate of BCG the incidence of tuberculous meningitis in children have decreased: in 1980 it was 3.27/100000; in 1988 it was 0.95/100000. The annual average incidence rate decreased by 14.28%.

[Protective effect of intradermal BCG on tuberculous meningitis]

The incidence of tuberculosis in Bahia, though declining, remains very high, and one of the severe forms of the disease is tubercular meningitis. This case-control study sought to compare confirmed cases of tubercular meningitis in children 0 to 14 years of age with members of a control group, matched as closely as possible for age (not more than about six months apart), who had shown no sign of meningitis or neurological disease. The comparison considered such factors as schooling of the parents, their occupations, exposure to the bacillus at home, and others. The study showed that failure to vaccinate heightens the risk of contracting the disease--a risk estimated at 11.7 with a confidence interval of 4.5 to 30.5, and an etiological component of 9.14%--and also that the risk is lower the earlier the child is vaccinated. With this study the authors wish to underscore the need to expand the coverage of intradermal BCG vaccination.