Tuberculosis burden in an urban population: a cross sectional tuberculosis survey from Guinea Bissau

<p>Abstract</p> <p>Background</p> <p>Little is known about the prevalence of pulmonary tuberculosis (TB) in low income countries. We conducted a cross sectional survey for pulmonary TB and TB symptoms in Bissau, Guinea-Bissau, in an urban cohort with known HIV prevalence. TB surveillance in the area is routinely based on passive case finding.</p> <p>Methods</p> <p>Two cohorts were selected based on a previous HIV survey, but only 52.5% of those enrolled in the adult cohort had participated in the HIV survey. One cohort included all adults living in 384 randomly selected houses; in this cohort 8% (135/1687) were HIV infected. The other included individuals 50 years or older from all other houses in the study area; of these 11% (62/571) were HIV infected. Symptom screening was done through household visits using a standardised questionnaire. TB suspects were investigated with sputum smear microscopy and X-ray.</p> <p>Results</p> <p>In the adult cohort, we found 4 cases among 2989 individuals screened, giving a total TB prevalence of 134/100,000 (95% CI 36-342/100,000). In the >50 years cohort, we found 4 cases among 571 individuals screened, giving a total prevalence of 701/100,000 (191-1784/100.000). Two of the eight detected TB cases were unknown by the TB program. Of the total TB cases five were HIV uninfected while three had unknown HIV status. The prevalence of TB symptoms was 2.1% (63/2989) and 10.3% (59/571) in the two cohorts respectively.</p> <p>Conclusions</p> <p>In conclusion we found a moderately high prevalence of pulmonary TB and TB symptoms in the general population, higher among elderly individuals. By active case finding unknown cases were detected. Better awareness of TB and its symptoms needs to be promoted in low income settings.</p

Attenuation of Toll-Like Receptor Expression and Function in Latent Tuberculosis by Coexistent Filarial Infection with Restoration Following Antifilarial Chemotherapy

Mycobacterium tuberculosis (Mtb) and filarial coinfection is highly prevalent, and the presence of filarial infections may regulate the Toll-like receptor (TLR)-dependent immune response needed to control Mtb infection. By analyzing the baseline and mycobacterial antigen–stimulated expression of TLR1, 2, 4, and 9 (in individuals with latent tuberculosis [TB] with or without filarial infection), we were able to demonstrate that filarial infection, coincident with Mtb, significantly diminishes both baseline and Mtb antigen-specific TLR2 and TLR9 expression. In addition, pro-inflammatory cytokine responses to TLR2 and 9 ligands are significantly diminished in filaria/TB-coinfected individuals. Definitive treatment of lymphatic filariasis significantly restores the pro-inflammatory cytokine responses in individuals with latent TB. Coincident filarial infection exerted a profound inhibitory effect on protective mycobacteria-specific TLR-mediated immune responses in latent tuberculosis and suggests a novel mechanism by which concomitant filarial infections predispose to the development of active tuberculosis in humans

Annual Risk of Tuberculous Infection Using Different Methods in Communities with a High Prevalence of TB and HIV in Zambia and South Africa

BACKGROUND: The annual risk of tuberculous infection (ARTI) is a key epidemiological indicator of the extent of transmission in a community. Several methods have been suggested to estimate the prevalence of tuberculous infection using tuberculin skin test data. This paper explores the implications of using different methods to estimate prevalence of infection and ARTI. The effect of BCG vaccination on these estimates is also investigated. METHODOLOGY/PRINCIPAL FINDINGS: Tuberculin surveys among school children in 16 communities in Zambia and 8 in South Africa (SA) were performed in 2005, as part of baseline data collection and for randomisation purposes of the ZAMSTAR study. Infection prevalence and ARTI estimates were calculated using five methods: different cut-offs with or without adjustments for sensitivity, the mirror method, and mixture analysis. A total of 49,835 children were registered for the surveys, of which 25,048 (50%) had skin tests done and 22,563 (90%) of those tested were read. Infection prevalence was higher in the combined SA than Zambian communities. The mirror method resulted in the least difference of 7.8%, whereas that estimated by the cut-off methods varied from 12.2% to 17.3%. The ARTI in the Zambian and SA communities was between 0.8% and 2.8% and 2.5% and 4.2% respectively, depending on the method used. In the SA communities, the ARTI was higher among the younger children. BCG vaccination had little effect on these estimates. CONCLUSIONS/SIGNIFICANCE: ARTI estimates are dependent on the calculation method used. All methods agreed that there were substantial differences in infection prevalence across the communities, with higher rates in SA. Although TB notification rates have increased over the past decades, the difference in cumulative exposure between younger and older children is less dramatic and a rise in risk of infection in parallel with the estimated incidence of active tuberculosis cannot be excluded

Silencing, Positive Selection and Parallel Evolution: Busy History of Primate Cytochromes c

Cytochrome c (cyt c) participates in two crucial cellular processes, energy production and apoptosis, and unsurprisingly is a highly conserved protein. However, previous studies have reported for the primate lineage (i) loss of the paralogous testis isoform, (ii) an acceleration and then a deceleration of the amino acid replacement rate of the cyt c somatic isoform, and (iii) atypical biochemical behavior of human cyt c. To gain insight into the cause of these major evolutionary events, we have retraced the history of cyt c loci among primates. For testis cyt c, all primate sequences examined carry the same nonsense mutation, which suggests that silencing occurred before the primates diversified. For somatic cyt c, maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses yielded the same tree topology. The evolutionary analyses show that a fast accumulation of non-synonymous mutations (suggesting positive selection) occurred specifically on the anthropoid lineage root and then continued in parallel on the early catarrhini and platyrrhini stems. Analysis of evolutionary changes using the 3D structure suggests they are focused on the respiratory chain rather than on apoptosis or other cyt c functions. In agreement with previous biochemical studies, our results suggest that silencing of the cyt c testis isoform could be linked with the decrease of primate reproduction rate. Finally, the evolution of cyt c in the two sister anthropoid groups leads us to propose that somatic cyt c evolution may be related both to COX evolution and to the convergent brain and body mass enlargement in these two anthropoid clades

Management of EuMusae leaf spot disease of banana caused by Mycosphaerella euMusae with Zimmu (Allium sativum× Allium cepa) leaf extract,

Leaf spot caused by Mycosphaerella spp. is considered as a serious threat of banana production worldwide (Arzanlou et al., 2008). This foliar disease causes major economic losses (Ploetz, 2000) and occurs in almost all banana growing regions in the world. In India, the disease has a serious impact in major banana growing states like Tamil Nadu, Kerala, Karnataka, Andhra Pradesh, Maharashtra (Jalgaon district), Gujarat, West Bengal and North-eastern hilly states of India (Anonymous, 2011a). Although previously the causal agent of leaf spot disease was not confirmed in India, recent studies using both morphological and molecular approaches revealed that the majority of 107 leaf spot infected samples (>99%) collected from different varieties and geographic locations showed the presence of M. eumusae Crous & X. Mour, which is known as Eumusae leaf spot disease (Anonymous, 2011b). Carlier et al. (2000) has also confirmed the presence of M. eumusae causing Septoria leaf spot disease in the Cavendish cv. Grand Naine in southern India.Among extracts of 33 plant species screened against Mycosphaerella eumusae, the causal agent of Eumusae leaf spot disease of banana, water extract of Cassia senna, Zimmu (Interspecific hybrid between Allium cepa × Allium sativum) and Rhincanthus nasutus provided 100% inhibition of spore germination and 1.7–2.0 cm zone of inhibition of mycelial growth under in vitro conditions. The maximum efficacy of mycelial inhibition was observed with Zimmu leaf extract. When Zimmu leaf extract was tested at different concentrations (5, 10, 25, 50 and 100% w/v), all tested concentrations provided complete inhibition of mycelial growth of the pathogen. The field evaluation of Zimmu leaf extract at different concentrations in cv. Grand Naine showed that the application of the water extract of Zimmu leaf at 50% concentration (w/v) provided 55% reduction of disease severity compared to the unsprayed control. Besides, the application of Zimmu leaf extract increased the value of youngest leaf spotted-0 (up to 60.5%) as well as increased the yield of banana (up to 46.8%) as compared to control. The effect of Zimmu in increasing the value of YLS-0 and the bunch yield was comparable with the chemical fungicide Propiconazole 25% EC (0.1%). Thin layer chromatography (TLC) analysis showed that among different major compounds, two lipid compounds (LP-B1 and LP-B2) extracted using methanol had the ability to inhibit M. eumusae growth (0.7–1.5 cm zone of inhibition). The gas chromatography–mass spectrometry (GC–MS) analysis of lipid bands revealed the presence of six different lipid compounds, which may be responsible for the growth inhibition of the pathogen. Since the application of water extract of Zimmu was found to be not only effective in controlling the leaf spot disease severity but also increased the number of green leaves and yield of banana fruits, the Zimmu extract can be used effectively in integrated disease management of Eumusae leaf spot disease for enhancing banana production in an ecologically sustainable manner

Why do tuberculosis suspects bypass local services to attend tuberculosis sanatorium?

Background: The Government Hospital of Thoracic Medicine (GHTM), Tambaram, in Kanchipuram district (formerly known as tuberculosis [TB] sanatorium), Tamil Nadu, draws patients from all over India although RNTCP services have been in place country-wide for a number of years. Objective: To document the reasons for patients with chest symptoms attending GHTM, Tambaram. Materials and Methods: In a prospective observational study, on a simple random sample basis, TB suspects attending the out-patient department of GHTM during the period January-March, 2006, were interviewed using a semi-structured interview schedule. Information on demographic, socio-economic characteristics and reasons for attending GHTM for health care was collected. Results: A total of 2,023 respondents attended GHTM during the study period; 56% were males, 67% were aged <45 years, 63% were literates and the average annual family income was Rs 25,000. Multiple reasons for attending GHTM were given: popularity of the centre (82%), perceived availability of good treatment (52%), referral by earlier treated patients (36%), expectation of specialized care (22%), referred by treating physicians (13%), and came for inpatient care (11%). Conclusion: Despite the availability of local RNTCP health services, many patients with chest symptoms made use of GHTM services due to the reputation of the former “TB sanatorium” in the community. The findings suggest that there is a need to improve community awareness of the availability of free diagnostic and treatment facilities locally under RNTCP