Scientific Production Directory
Books or Chapters
Search Scientific Production...
PublicationSoluble trace metals in aerosols over the tropical south-east Pacific offshore of Peru(Copernicus GmbH, 2016-02-12)Bulk aerosol samples collected during cruise M91 of FS Meteor off the coast of Peru in December 2012 were analysed for their soluble trace metal (Fe, Al, Mn, Ti, Zn, V, Ni, Cu, Co, Cd, Pb, Th) and major ion (including NO-3 and NH+4/content. These data are among the first recorded for trace metals in this relatively poorly studied region of the global marine atmosphere. To the north of ∼13° S, the concentrations of several elements (Fe, Ti, Zn, V, Ni, Pb) appear to be related to distance from the coast. At the south of the transect (∼15-16° S), elevated concentrations of Fe, Cu, Co, and Ni were observed, and we calculated dry deposition fluxes of soluble Cu approximately an order of magnitude higher than a recent model-based estimate of total Cu deposition to the region. The model did not take account of emissions from the large smelting facilities in the south of Peru and northern Chile, and our results may indicate that these facilities constitute an important source of trace metals to the region. Calculated dry deposition fluxes (3370-17800 and 16-107 nmolm-2 d-1 for inorganic nitrogen and soluble Fe respectively) indicated that atmospheric input to the waters of the Peru upwelling system contains an excess of Fe over N, with respect to phytoplankton requirements. This may be significant as primary production in these waters has been reported to be limited by Fe availability, but atmospheric deposition is unlikely to be the dominant source of Fe to the system.
PublicationLessons Learned from Implementation of an Interferon Gamma Release Assay to Screen for Latent Tuberculosis Infection in a Large Multicenter Observational Cohort Study in Brazil(American Society for Microbiology, 2021)The interferon gamma release assay (IGRA) has emerged as a useful tool for identifying latent tuberculosis infection (LTBI). This assay can be performed through testing platforms such as the QuantiFERON-TB Gold Plus (QFT-Plus) assay. This in vitro test has been incorporated into several guidelines worldwide and has recently been considered by the World Health Organization (WHO) for the diagnosis of LTBI. The possibility of systematically implementing IGRAs such as the QFT-Plus assay in centers that perform LTBI screening has been accelerated by the decreased availability of the tuberculin skin test (TST) in several countries. Nevertheless, the process to implement IGRA testing in routine clinical care has many gaps. The study utilized the expertise acquired by the laboratory teams of the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil consortium during study protocol implementation of LTBI screening of tuberculosis (TB) close contacts. RePORT-Brazil includes clinical research sites from Brazilian cities and is the largest multicenter cohort of TB close contacts in the country to date. Operational and logistical challenges faced during IGRA implementation in all study laboratories are described, as well as the solutions that were developed and led to the successful establishment of IGRA testing in RePORT-Brazil. The descriptions of the problems identified and resolved in this study can assist laboratories implementing IGRAs, in addition to manufacturers of IGRAs providing effective technical support. This will facilitate the implementation of IGRA testing in countries with large TB burdens, such as Brazil. IMPORTANCE The IGRA has emerged as a useful tool for identifying persons with LTBI. Although the implementation of IGRAs is of utmost importance, to our knowledge there is scarce information on the identification of logistical and technical challenges for systematic screening for LTBI on a large scale. Thus, the descriptions of the problems identified and resolved in this study can assist laboratories implementing IGRAs, in addition to manufacturers of IGRAs providing effective technical support. This will facilitate the implementation of IGRA testing in countries with large TB burdens, such as Brazil.
PublicationDeterminants of losses in the tuberculosis infection cascade of care among children and adolescent contacts of pulmonary tuberculosis cases: A Brazilian multi-centre longitudinal study(Elsevier Ltd, 2022)Background: Approximately 10% of the global tuberculosis (TB) burden is in children. Identification, diagnosis, and early treatment of Mycobacterium tuberculosis infection (TBI) is critical to prevent progression to TB in children. The risk of TB, including severe disease, is highest in children <5 years old. We evaluated the cascade of TBI care among child and adolescent TB contacts to identify factors associated with losses in the cascade. Methods: Close contacts ≤ 18 years old of pulmonary TB patients enrolled between 2015 and 2019 in a multi-centre Brazilian cohort were followed for up to 24 months and classified according to age groups: <5 years, 5–9 years, 10–14 years and 15–18 years. Data on clinical investigation, radiographic examination, IGRA testing at baseline and 6 months, initiation and completion of TB preventive treatment (TPT) were collected. Multivariable regression analyses identified factors associated with TBI and losses in the cascade of care in children and adolescents. Findings: Among 1795 TB contacts initially identified, 530 (29·5%) were ≤18 years old. Losses for all steps in the cascade were especially high in children <5 years old (88%) because at this age all contacts are recommended to initiate TPT. As a proportion of all children, completion of TPT was low (between 10% and 13%) in all age-groups. Furthermore, multivariable regression revealed that younger age of contacts and TB index cases who were female, had pulmonary cavities, and persistent cough were independently associated with losses in the cascade of care among persons ≤18 years old. Interpretation: Losses in the TBI cascade were the highest among children <5 years, which was the group at highest risk for TB among the four age groups. The findings highlight the need to improve screening, initiation, and completion of TPT of young children who are close contacts of people with TB in Brazil. Funding: National Institutes of Allergy and Infectious Diseases.
PublicationThe Effect of Diabetes and Prediabetes on Mycobacterium tuberculosis Transmission to Close Contacts(Oxford University Press, 2021)Background: It is unknown whether dysglycemia is associated with Mycobacterium tuberculosis transmission. Methods: We assessed epidemiological and clinical characteristics of patients with culture-confirmed pulmonary tuberculosis and their close contacts, enrolled in a multicenter prospective cohort in Brazil. Contacts were investigated at baseline and 6 months after enrollment. QuantiFERON positivity at baseline and conversion (from negative to positive at month 6) were compared between subgroups of contacts according to glycemic status of persons with tuberculosis (PWTB) as diabetes mellitus (DM) or prediabetes. Multivariable mixed-effects logistic regression models were performed to test independent associations with baseline QuantiFERON positive and QuantiFERON conversion. Results: There were 592 PWTB (153 DM, 141 prediabetes, 211 normoglycemic) and 1784 contacts, of whom 658 were QuantiFERON-positive at baseline and 106 converters. Multivariable analyses demonstrated that tuberculosis-prediabetes cases, acid-fast bacilli-positive, pulmonary cavities, and living with someone who smoked were independently associated with QuantiFERON positive in contacts at baseline. DM, persistent cough, acid-fast bacilli-positive, and pulmonary cavities in tuberculosis source cases were associated with QuantiFERON conversion. Conclusions: Contacts of persons with pulmonary tuberculosis and dysglycemia were at increased risk of being QuantiFERON positive at baseline or month 6. Increased focus on such close contacts could improve tuberculosis control.
PublicationSRTM 3" comparison with local information: Two examples at national level in Peru(Walter de Gruyter GmbH, 2012-06-01)The access to the high resolution digital terrain models (DEM) generated from the data collected by the Shuttle Radar Topography Mission (SRTM) of NASA is freely available to the public. Consequently it has become a source of topographic information which is of great value to scientists involved in geophysical or geodetic analysis. Despite the efforts of the Consultative Group on International Agricultural Research (CGIAR), to validate and complement the information contained in these DEMs (currently offered as version 4.1), they still need to be checked for their accuracy in certain regions of the planet. In this paper, the vertical accuracy of the SRTM 3" version 4.1 DEM was analyzed in several areas of Peru using two sets of control points: the height of the district capitals (the minor politics units) and the heights of the weather and hydrological stations from the National Meteorology and Hydrology Service (SENAMHI) of Peru. The comparison shows that the height differences are independent of the altitude, latitude and longitude of the evaluated points. They are rather related to the aspect of the terrain and to the way the SRTM data were acquired. It shows that the mean square of the height differences at national level was ±20 m for district capitals and ±25 m for the SENAMHI stations. This is slightly larger than the overall accuracy of the SRTM ±16 m.
metadata only access
OCDE Knowledge Area
1980 - 1999
2000 - 2019
2020 - 2023