Rocha C.,IFHAD Innovation for Health and Development |
Rocha C.,Cayetano Heredia Peruvian University |
Montoya R.,IFHAD Innovation for Health and Development |
Zevallos K.,IFHAD Innovation for Health and Development |
And 25 more authors.
International Journal of Tuberculosis and Lung Disease | Year: 2011
SETTING: Tuberculosis (TB) affected households in impoverished shantytowns, Lima, Peru. OBJECTIVE: To evaluate socio-economic interventions for strengthening TB control by improving uptake of TB care and prevention services. DESIGN: Barriers to TB control were characterised by interviews with TB-affected families. To reduce these barriers, a multidisciplinary team offered integrated community and household socio-economic interventions aiming to: 1) enhance uptake of TB care by education, community mobilisation and psychosocial support; and 2) reduce poverty through food and cash transfers, microcredit, microenterprise and vocational training. An interim analysis was performed after the socio-economic interventions had been provided for 2078 people in 311 households of newly diagnosed TB patients for up to 34 months. RESULTS: Poverty (46% earned
Wingfield T.,IFHAD Innovation for Health and Development |
Wingfield T.,Imperial College London |
Wingfield T.,Monsall Infectious Diseases Unit |
Schumacher S.G.,IFHAD Innovation for Health and Development |
And 19 more authors.
Journal of Infectious Diseases | Year: 2014
Background. Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years. Methods. Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosisexposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained. Results. Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001). Conclusions. The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis. © The Author 2014.
Chew R.,IFHAD Innovation for Health and Development |
Chew R.,University of Cambridge |
Chew R.,Cayetano Heredia Peruvian University |
Calderon C.,Cayetano Heredia Peruvian University |
And 20 more authors.
BMC Infectious Diseases | Year: 2011
Background: Bleach-sedimentation may improve microscopy for diagnosing tuberculosis by sterilising sputum and concentrating Mycobacterium tuberculosis. We studied gravity bleach-sedimentation effects on safety, sensitivity, speed and reliability of smear-microscopy.Methods: This blinded, controlled study used sputum specimens (n = 72) from tuberculosis patients. Bleach concentrations and exposure times required to sterilise sputum (n = 31) were determined. In the light of these results, the performance of 5 gravity bleach-sedimentation techniques that sterilise sputum specimens (n = 16) were compared. The best-performing of these bleach-sedimentation techniques involved adding 1 volume of 5% bleach to 1 volume of sputum, shaking for 10-minutes, diluting in 8 volumes distilled water and sedimenting overnight before microscopy. This technique was further evaluated by comparing numbers of visible acid-fast bacilli, slide-reading speed and reliability for triplicate smears before versus after bleach-sedimentation of sputum specimens (n = 25). Triplicate smears were made to increase precision and were stained using the Ziehl-Neelsen method.Results: M. tuberculosis in sputum was successfully sterilised by adding equal volumes of 15% bleach for 1-minute, 6% for 5-minutes or 3% for 20-minutes. Bleach-sedimentation significantly decreased the number of acid-fast bacilli visualised compared with conventional smears (geometric mean of acid-fast bacilli per 100 microscopy fields 166, 95%CI 68-406, versus 346, 95%CI 139-862, respectively; p = 0.02). Bleach-sedimentation diluted paucibacillary specimens less than specimens with higher concentrations of visible acid-fast bacilli (p = 0.02). Smears made from bleach-sedimented sputum were read more rapidly than conventional smears (9.6 versus 11.2 minutes, respectively, p = 0.03). Counting conventional acid-fast bacilli had high reliability (inter-observer agreement, r = 0.991) that was significantly reduced (p = 0.03) by bleach-sedimentation (to r = 0.707) because occasional strongly positive bleach-sedimented smears were misread as negative.Conclusions: Gravity bleach-sedimentation improved laboratory safety by sterilising sputum but decreased the concentration of acid-fast bacilli visible on microscopy, especially for sputum specimens containing high concentrations of M. tuberculosis. Bleach-sedimentation allowed examination of more of each specimen in the time available but decreased the inter-observer reliability with which slides were read. Thus bleach-sedimentation effects vary depending upon specimen characteristics and whether microscopy was done for a specified time, or until a specified number of microscopy fields had been read. These findings provide an explanation for the contradictory results of previous studies. © 2011 Chew et al; licensee BioMed Central Ltd.