Mycobacterium tuberculosis infection in First Nations preschool children in Alberta: implications for BCG (bacille Calmette-Guérin) vaccine withdrawal

BACKGROUND

On April 1, 2004, BCG (bacille Calmette-Guérin), a tuberculosis (TB) control vaccine, was discontinued in all but four high-risk communities in Alberta. To confirm the safety of vaccine withdrawal, and for future planning, the annual risk of infection (ARI) was determined in preschool First Nations children.

METHODS

First Nations children born into reserve communities in Alberta between April 1, 1998 and March 31, 2004, and still living on reserve in 2004-2005, were identified. Health centre TB histories were validated by cross-referencing the birth cohort with the provincial TB Registry. Children that were not BCG vaccinated and not known to be tuberculin skin test (TST) positive underwent a TST. Birth cohort children were grouped as follows: (i) BCG vaccinated; (ii) BCG non-vaccinated, no TST; (iii) BCG non-vaccinated, TST; (iv) BCG vaccination status unknown. The ARI was calculated and the age and community characteristics of the groups were compared.

RESULTS

There were 8447 children in the 6-year birth cohort, 4699 (55.6%) vaccinated, 2696 (31.9%) non-vaccinated, and 1052 (12.5%) whose vaccination status was unknown. Of the non-vaccinated children, 1921 (71.3%) were tested and only 2 were TST positive. No other TST positive, BCG non-vaccinated children were identified in the TB Registry cross-match. The prevalence of infection in 2004-2005 was 0.1% and the ARI was 0.03%. The community risk of TB exposure was comparable in tuberculin-tested and non-tested BCG non-vaccinated children.

CONCLUSION

In low BCG-uptake First Nations communities in Alberta, the ARI is low and it is safe to withdraw BCG.

Neuregulin 1 (8p12) and childhood-onset schizophrenia: susceptibility haplotypes for diagnosis and brain developmental trajectories

Childhood-onset schizophrenia (COS), defined as onset of psychosis by the age of 12, is a rare and malignant form of the illness, which may have more salient genetic influence. Since the initial report of association between neuregulin 1 (NRG1) and schizophrenia in 2002, numerous independent replications have been reported. In the current study, we genotyped 56 markers (54 single-nucleotide polymorphisms (SNPs) and two microsatellites) spanning the NRG1 locus on 78 COS patients and their parents. We used family-based association analysis for both diagnostic (extended transmission disequilibrium test) and quantitative phenotypes (quantitative transmission disequilibrium test) and mixed-model regression. Most subjects had prospective anatomic brain magnetic resonance imaging (MRI) scans at 2-year intervals. Further, we genotyped a sample of 165 healthy controls in the MRI study to examine genetic risk effects on normal brain development. Individual markers showed overtransmission of alleles to affecteds (P=0.009-0.05). Further, several novel four-marker haplotypes demonstrated significant transmission distortion. There was no evidence of epistasis with SNPs in erbB4. The risk allele (0) at 420M9-1395 was associated with poorer premorbid social functioning. Further, possession of the risk allele was associated with different trajectories of change in lobar volumes. In the COS group, risk allele carriers had greater total gray and white matter volume in childhood and a steeper rate of subsequent decline in volume into adolescence. By contrast, in healthy children, possession of the risk allele was associated with different trajectories in gray matter only and was confined to frontotemporal regions, reflecting epistatic or other illness-specific effects mediating NRG1 influence on brain development in COS. This replication further documents the role of NRG1 in the abnormal brain development in schizophrenia. This is the first demonstration of a disease-specific pattern of gene action in schizophrenia.

Rapid sonic characterisation of sewer change and obstructions

This paper reports on the development of a low-cost, rapidly deployable sensor for surveying live sewers for blockages and structural failures. The anticipated cost is an order of magnitude lower than current techniques. The technology is based on acoustic normal model decomposition, The instrument emits short coded acoustic signals which are reflected from any sewer wall defect. The acoustic signals can be short Gaussian pulses or longer sinusoidal sweeps and pseudo-random noise. The processing algorithms used on the reflected signal can predict the extent and geometry of the pipe deformation, and the locations and approximate size of common blockages. The effect of the water level on the frequency of the fundamental mode has also been investigated. It is shown that the technique can be adapted to work reliably in relatively large 600 mm diameter sewer pipes.

First Report of Phytophthora europaea in Oak Forests in the Eastern and North-Central United States

In 2003 and 2004, soils in oak forest ecosystems in nine central and eastern states of the United States were surveyed for Phytophthora spp. Soil samples were collected around healthy and symptomatic trees. Symptoms included dieback of branches, gaps in lateral branch systems, yellowing of foliage, wilting and clustering of leaves, and the presence of epicormic shoots. Soil subsamples were collected in each of the four cardinal directions and at a distance of 1 to 2 m from the base of a tree. The four subsamples were bulked to produce a sample of approximately 2,000 ml. In the laboratory, each sample was mixed thoroughly and a single 250-g subsample was flooded with 500 ml of distilled water and baited with Quercus robur leaflets for 3 to 5 days at 17 to 20°C. Discolored leaflets were examined microscopically (×200) and those with sporangia typical of Phytophthora spp. were plated on PARPNH selective medium (1). Phytophthora europaea was recovered from soil samples collected from Q. alba in West Virginia, Q. rubra in Minnesota, West Virginia, and Wisconsin, Q. phellos in Ohio, and Q. velutina in Pennsylvania. Cultures were identified as P. europaea by their morphological, physiological, and molecular characteristics (4). Average dimensions of nine isolates were determined. Oogonia were 40 ± 3.9 μm in diameter and often had few bullet protuberances and tapered bases; oospores mostly filled the oogonia and averaged 36 ± 3.7 μm; sporangia dimensions averaged 42 ± 6.1 × 30 ± 4.1 μm with a length/width ratio of 1:4. Isolates produced larger oogonia and oospores but had similar sporangia length/width ratios comparable to the species description (4). Growth optimum (5.8 to 6.9 mm day^-1) on V8 juice agar (V8A) occurred at 25°C. On potato dextrose agar, colonies produced dense, felt-like mycelia, often with a central mound of aerial hyphae. DNA also was extracted from eight representative isolates and the internal transcribed spacer (ITS) region of rDNA from each isolate was amplified and sequenced. ITS sequences were identical to those of P. europaea in the NCBI GenBank database (Accession No. DQ313222). Pathogenicity of six isolates (one from each site) was confirmed by wounding stems of 2-year-old Q. alba, Q. rubra, and Q. velutina seedlings and inoculating wounds with V8A plugs (6 mm) containing mycelia; V8A plugs without mycelia were used for controls. Two months after inoculation, P. europaea was reisolated on PARPNH medium from advancing lesions on all inoculated seedlings but was not isolated from control plants. Mean lesion lengths on seedlings inoculated with P. europaea were significantly greater (P < 0.05) than those on control plants; lesions averaged 0.46 cm on Q. alba, 1.38 cm on Q. rubra, and 1.01 cm on Q. velutina. Previously, P. europaea only was reported from oak trees and soil in forests of Austria, France, and Germany (1-4). These findings extend the current distribution of P. europaea and raise questions about its origin and role in the health of oak forests in eastern and north-central United States. Q. alba, Q. phellos, Q. rubra, and Q. velutina are new host associations for P. europaea. References: (1) Y. Balci and E. Halmschlager. For. Pathol. 33:157, 2003. (2) E. Hansen and C. Delatour. Ann. Sci. For. 56:539, 1999. (3) G. Hartmann and R. Blank. Forst Holz. 57:539, 2002. (4) T. Jung et al. Mycol. Res. 106:397, 2002.

Multicolour FISH and quantitative PCR can detect submicroscopic deletions in holoprosencephaly patients with a normal karyotype

Holoprosencephaly (HPE) is the most common structural malformation of the developing forebrain. At birth, nearly 50% of children with HPE have cytogenetic anomalies. Approximately 20% of infants with normal chromosomes have sequence mutations in one of the four main HPE genes (SHH, ZIC2, SIX3, and TGIF). The other non-syndromic forms of HPE may be due to environmental factors or mutations in other genes, or potentially due to submicroscopic deletions of HPE genes. We used two complementary assays to test for HPE associated submicroscopic deletions. Firstly, we developed a multicolour fluorescent in situ hybridisation (FISH) assay using probes for the four major HPE genes and for two candidate genes (DISP1 and FOXA2). We analysed lymphoblastoid cell lines (LCL) from 103 patients who had CNS findings of HPE, normal karyotypes, and no point mutations, and found seven microdeletions. We subsequently applied quantitative PCR to 424 HPE DNA samples, including the 103 samples studied by FISH: 339 with CNS findings of HPE, and 85 with normal CNS and characteristic HPE facial findings. Microdeletions for either SHH, ZIC2, SIX3, or TGIF were found in 16 of the 339 severe HPE cases (that is, with CNS findings; 4.7%). In contrast, no microdeletion was found in the 85 patients at the mildest end of the HPE spectrum. Based on our data, microdeletion testing should be considered as part of an evaluation of holoprosencephaly, especially in severe HPE cases.

Inhaled nitric oxide treatment of patients with pulmonary tuberculosis evidenced by positive sputum smears

Endogenous nitric oxide (NO) has antimycobacterial properties. We tested the hypothesis that exogenous (inhaled) NO can be safely delivered and can accelerate airway disinfection for pulmonary tuberculosis patients treated with standard therapy. Exogenous NO administered at 80 ppm for 72 h can be safely delivered but does not accelerate airway disinfection.

Tuberculosis: Still Overlooked as a Cause of Community-acquired Pneumonia?How Not to Miss it

Tuberculosis (TB) is often mistaken for community-acquired pneumonia (CAP). To avoid missing the diagnosis, we recommend that any CAP patient with upper lobe infiltrate, cavitation, miliary pattern, hemoptysis or >1 month of any of cough, fever, malaise,weakness, night sweats, or significant weight loss, should have sputa submitted for Mycobacterium tuberculosis smear and culture. Any CAP patient failing or relapsing after empiric therapy should be investigated for TB. In the presence of HIV with low CD4 count (< or = 200 cells/mL), the presentation may be atypical, and therefore sputa should be submitted for M tuberculosis. Any HIV patient, regardless of CD4 count, with a known history of positive tuberculin skin test, previous TB, or recent exposure to TB, who presents with CAP, should be investigated for TB.

Blind and sighted pedestrians' judgments of gaps in traffic at roundabouts

This paper reports two experiments about street crossing under conditions of free flowing traffic, with a focus on modem roundabout intersections. Experiment 1 was conducted at three roundabouts varying in size and traffic volume. Six totally blind and six sighted adults judged whether gaps in traffic were long enough to permit crossing to the median (splitter) island before the next vehicle arrived. Gap distributions and measures of judgment quality are reported. Overall, blind participants were about 2.5 times less likely to make correct judgments than sighted participants, took longer to detect crossable gaps, and were more likely to miss crossable gaps altogether. However, the differences were significant only at the two higher volume roundabouts. In Experiment 2, we evaluated the response of drivers to pedestrians with and without mobility devices (i.e., long canes, dog guides). The experiment was conducted at a single-lane roundabout, a midblock crossing, and a two-way-stop-controlled intersection. Site-specific characteristics appeared to have a greater impact on drivers' yielding than did a mobility device. Actual or potential applications of this research include the development of methods for assessing pedestrian safety and driver behavior as well as identifying intersections that may require modification in order to be accessible to blind pedestrians.

Transmission characteristics of tuberculosis in the foreign-born and the Canadian-born populations of Alberta, Canada

SETTING

All notified cases of tuberculosis in the province of Alberta, Canada, 1994-1998.

OBJECTIVE

To compare the transmission characteristics of tuberculosis among foreign-born and Canadian-born cases.

DESIGN

Retrospective analysis using DNA fingerprinting (IS6110 restriction fragment length polymorphism and spoligotyping) and patient information from the Alberta Tuberculosis Registry. Transmission indexes were determined by calculating the average number of culture-positive pulmonary cases generated by a single source case.

RESULTS

Of the 750 cases of active tuberculosis, 437 (58.3%) were in the foreign-born. DNA fingerprinting of Mycobacterium tuberculosis isolates from all 573 culture-positive cases over the 5 years from 1994 to 1998 showed that there was significantly less clustering among foreign-born isolates (9.8%) compared to Canadian-born non-Aboriginal (28.8%) and Aboriginal (44.7%) isolates. The transmission index was significantly higher for males, lower for those > or =65 years of age, and higher for Aboriginals.

CONCLUSION

Although cases of tuberculosis in the foreign-born constitute the majority in Alberta, there is little transmission to other foreign-born or to Canadian-born individuals. Transmission of tuberculosis among the Aboriginal population remains a significant problem in Alberta.

Pediatric tuberculosis in Alberta First Nations (1991-2000): outbreaks and the protective effect of bacille Calmette-Guérin (BCG) vaccine

BACKGROUND

The tuberculosis control strategy of vaccinating First Nations newborns with BCG (bacille Calmette-Guerin) is currently undergoing re-evaluation in Canada. Review of recent pediatric tuberculosis morbidity could inform this re-evaluation.

METHODS

Potential source cases and pediatric cases of tuberculosis from Alberta First Nations were identified over the 10 years 1991-2000. The distribution of pediatric disease was described. The effect of BCG on tuberculosis morbidity in two large outbreaks was determined.

RESULTS

A total of 57 potential source cases and 41 pediatric cases of tuberculosis were reported from 17 (41.5%) and 8 (19.5%) of the 41 on-reserve First Nation Community Health Centres, respectively. Three outbreaks traceable to three source cases accounted for 34 (18, 3, and 13, respectively) of the 41 (82.9%) pediatric cases. Each outbreak was spatially and temporally separate from the other. Each outbreak strain of Mycobacterium tuberculosis had a unique DNA fingerprint. In the largest outbreaks, disease-to-infection ratios (secondary case rates) were higher in newly infected unvaccinated versus vaccinated close pediatric contacts (12/13 [92.3%] versus 7/15 [46.7%], p=0.02), but the infection rate was almost certainly falsely high in the BCG vaccinated. One unvaccinated child had a brain tuberculoma in addition to primary pulmonary tuberculosis.

CONCLUSION

For most Alberta First Nations communities, the spatial and temporal distribution of disease, and the meager impact on morbidity, challenge the rationale for continued use of BCG.

Pediatric tuberculosis in Alberta First Nations (1991-2000): outbreaks and the protective effect of bacille Calmette-Guérin (BCG) vaccine

BACKGROUND

The tuberculosis control strategy of vaccinating First Nations newborns with BCG (bacille Calmette-Guerin) is currently undergoing re-evaluation in Canada. Review of recent pediatric tuberculosis morbidity could inform this re-evaluation.

METHODS

Potential source cases and pediatric cases of tuberculosis from Alberta First Nations were identified over the 10 years 1991-2000. The distribution of pediatric disease was described. The effect of BCG on tuberculosis morbidity in two large outbreaks was determined.

RESULTS

A total of 57 potential source cases and 41 pediatric cases of tuberculosis were reported from 17 (41.5%) and 8 (19.5%) of the 41 on-reserve First Nation Community Health Centres, respectively. Three outbreaks traceable to three source cases accounted for 34 (18, 3, and 13, respectively) of the 41 (82.9%) pediatric cases. Each outbreak was spatially and temporally separate from the other. Each outbreak strain of Mycobacterium tuberculosis had a unique DNA fingerprint. In the largest outbreaks, disease-to-infection ratios (secondary case rates) were higher in newly infected unvaccinated versus vaccinated close pediatric contacts (12/13 [92.3%] versus 7/15 [46.7%], p=0.02), but the infection rate was almost certainly falsely high in the BCG vaccinated. One unvaccinated child had a brain tuberculoma in addition to primary pulmonary tuberculosis.

CONCLUSION

For most Alberta First Nations communities, the spatial and temporal distribution of disease, and the meager impact on morbidity, challenge the rationale for continued use of BCG.

Prognostic markers in node-negative breast cancer: A prospective study

BACKGROUND

Despite years of research, it is still unclear which women with node-negative (N-) breast cancer will need adjuvant chemotherapy and which women are being treated unnecessarily. Our goal was to determine which factors best predicted disease free survival (DFS) or cancer-specific overall survival (OS) and, therefore, select the correct patients for treatment. A total of 11 parameters were measured: estrogen receptor (ER), progesterone receptor (PR), age, race, ploidy status, %G0/G1 (% non-DNA synthesis), %S (% S-phase), cathepsin D status, size, stage, and histologic grade.

RESULTS

In this prospective study, we followed 556 N- patients diagnosed between 1991 and 1996. The tumors were 56% ER+, 51% PR+, 30% diploid, with a mean %S of 8.9%. The level of cathepsin D ranged from 0.50 to 155 pmol/mg of protein with a mean of 42.9 pmol/mg of protein. There were 87 recurrences (16%) and 72 cancer deaths (13%), with a median follow-up of 7.8 years. Ploidy status (p = 0.01), S-phase activity (p = 0.003), G1 phase activity (p = 0.02) and age (p = 0.01) were able to significantly predict DFS in a univariate manner. All of the measurable factors were significant or borderline significant in predicting OS in a univariate manner except for age, race, and ER status. In multivariate analysis with S-phase included, it was the only remaining factor in DFS and OS; with S-phase excluded, age and ploidy status remained as factors for DFS in stepwise regression, while PR, size, and cathepsin D were the remaining factors that predicted cancer-specific OS. The effect of adjuvant treatment on prognosis was also analyzed.

CONCLUSIONS

Both biochemical and clinical parameters have the potential to predict prognosis for N- breast cancer. In this large prospective clinical trial, with a median follow-up of 7.8 years, no individual marker adequately predicted the prognosis for an individual patient. %S activity was the best independent marker, but only 77% of the tumors provided this value. Subset analysis provided improved prognostication, but there were limits to its utility. These data represents a definitive study starting in 1991 and ending in 2002.

Attenuation characteristics of the fundamental modes that propagate in buried iron water pipes

The attenuation of the fundamental non-torsional modes that propagate down buried iron water pipes has been studied. The mode shapes, mode attenuation due to leakage into the surrounding medium and the scattering of the modes as they interact with pipe joints and fittings have been investigated. In the low frequency region the mode predicted to dominate over significant propagation distances approximates a plane wave in the water within the pipe. The established acoustic technique used to locate leaks in buried iron water pipes assumes that leak noise propagates as a single non-dispersive mode at a velocity related to the low frequency asymptote of this water borne mode. Experiments have been conducted on buried water mains at test sites in the UK to verify the attenuation and velocity dispersion predictions.

Anti-tumour necrosis factor agents and tuberculosis risk: mechanisms of action and clinical management

Cases of active tuberculosis have been reported worldwide with the use of therapeutic agents that inhibit tumour necrosis factor (TNF) alpha. TNFalpha has a central role in mycobacterial infection and disease. Accordingly, progression of recently acquired tuberculosis infection or reactivation of remotely acquired infection should be expected with the use of anti-TNF agents. The available in-vitro and epidemiological evidence for the two currently approved agents, infliximab and etanercept, shows that the risk of development of active tuberculosis is greater with infliximab. Tuberculin skin testing (TST) should be undertaken before any significant immunosuppressive therapy including these agents, though the possibility of false-negative reactions in immunocompromised populations must be borne in mind. A positive TST should be followed by medical assessment and chest radiography, as well as by other tests judged appropriate by the physician to identify active disease. Active tuberculosis must be treated appropriately before initiation of treatment with an anti-TNF agent. Treatment of latent tuberculosis can be considered on an individual basis for TST-negative patients receiving anti-TNF agents when significant risk factors for infection are present.