Environmental and behavioural determinants of leptospirosis transmission : a systematic review

BACKGROUND: Leptospirosis is one of the most widespread zoonotic diseases, which is of global medical and veterinary importance, and also a re-emerging infectious disease. The main tracks of transmission are known; however, the relative importance of each of the components and the respective environmental risk factors are unclear. We aimed to assess and specify quantitative evidence of environmental risks of leptospirosis transmission. METHODS/FINDINGS: A database of pre-selected studies, with publication dates from 1970 until 2008, was provided by an expert group. The database has been updated until 2015 using a text mining algorithm. Study selection was based on stringent quality criteria. A descriptive data analysis was performed to calculate the medians of the log transformed odds ratios. From a selection of 2723 unique publications containing information on leptospirosis, 428 papers dealing with risk factors were identified. Of these, 53 fulfilled the quality criteria, allowing us to identify trends in different geo-climatic regions. Water associated exposures were, with few exceptions, associated with an increased leptospirosis risk. In resource poor countries, floods and rainfall were of particular importance, whereas recreational water activities were more relevant in developed countries. Rodents were associated with increased leptospirosis risk, but the variation among studies was high, which might be partly explained by differences in exposure definition. Livestock contact was commonly associated with increased risk; however, several studies found no association. The median odds ratios associated with dog and cat contacts were close to unity. Sanitation and behavioural risk factors were almost always strongly associated with leptospirosis, although their impact was rarely investigated in Europe or North America. CONCLUSION: This review confirms the complex environmental transmission pathways of leptospirosis, as previously established. Although, floods appeared to be among the most important drivers on islands and in Asia, the consistent pattern observed for exposure to rodents and behavioural and sanitation related risk factors indicate potential areas for intervention

Can whole-body diffusion-weighted magnetic resonance sequence replace 18F-fluorodeoxyglucose-positron emission tomography in the management of lymphoma?

Abstract Background Positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG-PET/CT) is the gold standard for staging and treatment response assessment in patients with malignant lymphoma. However, 18F-FDG-PET/CT uses significant dose of ionizing radiation, which is a potential risk of secondary malignancies. Whole-body diffusion-weighted MRI (WB-DW-MRI) is a promising, radiation-free alternative for staging and assessment of response in patients with lymphoma. However, till now, WB-MRI is not routinely used in patients with lymphoma. The aim of this study was to assess the role of whole-body diffusion-weighted MR sequence in management of lymphoma, compared to conventional FDG-PET CT, as well as to ascertain whether WB-DW-MRI is a good alternative to FDG PET/ CT for the diagnosis of lymphoma and subsequent treatment evaluation. The study was conducted on 20 patients (17males, 3 females) who presented with histopathologically proved lymphoma for initial evaluation or for follow-up. All patients were subjected to full history taking, clinical examination report review, as well as other imaging modalities whenever available, followed by FDG PET/CT examination. Patients were then further reevaluated by whole-body diffusion-weighted imaging to determine whether they were comparable in the diagnostic and or treatment response assessment. Results Thirty-six of our patients had non-Hodgkin’s lymphoma (NHL), while 4 had Hodgkin’s lymphoma (HL). Whole-Body DW-MRI and FDG PET/CT results assessment was done. Comparison between WB-DWI and FDG PET/CT revealed moderate agreement (κ = 0.573) for nodal regions and very good agreement (κ = 0.835) for extra-nodal regions. Finally, individual nodal regions varied from moderate to very good at a kappa value of > 0.69; with the exception of mediastinal hilar nodes which were fair (κ = 0.348). Conclusion WB-DWI demonstrates potential as a radiation-free alternative to PET/CT for staging and treatment response assessment in lymphoma patients. However, larger multicenter studies are still needed to validate WB-DW-MRI's diagnostic performance across diverse lymphoma subtypes

Data extraction table.

<p>Complete references for these studies are presented in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003843#pntd.0003843.s002" target="_blank">S1 Text</a></p><p>Data extraction table.</p

Flowchart of systematic review and identification of articles.

<p>Flowchart of systematic review and identification of articles.</p

Number of eligible studies stratified by country.

<p>Number of eligible studies stratified by country.</p