Cadmium uptake in radish (Raphanus sativus L.) and surficial contamination: implications for food safety and local soil management

Journal of Soils and Sediments - Soil management strategies for agricultural lands contaminated with potentially toxic trace elements, especially cadmium (Cd), are still inadequate and require a...     

A capture-recapture analysis in a challenging environment: assessing the epidemiological situation of foot-and-mouth disease in Cambodia

We performed a two-source capture-recapture analysis for estimating the true number of villages that experienced clinical cases of foot-and-mouth disease (FMD) in 2009 in Svay Rieng province, Cambodia, and assessing the completeness of the official case-reporting procedure. As a first source, we used the 2009 official dataset made up of the 15 FMD-infected villages that were reported to the provincial authorities, and enlarged this list by assuming that all the villages located at less than 4 km from one of these villages also experienced clinical cases in 2009. In addition, we created a retrospective detection protocol using participatory tools cross-checked against a serological survey that detected 13 infected villages. The capture-recapture analysis of these two detection sources led us to the conclusion that 315 (CI(95%) 117-514) villages experienced clinical cases of foot-and-mouth disease in Svay Rieng province in 2009, corresponding to a village-level annual prevalence rate of 0.46 (CI(95%) 0.17-0.74). The official reporting rate to provincial authorities could therefore be evaluated at 0.05 (CI(95%) 0.03-0.13). An analysis of the sensitivity of the estimation of the number of cases to the radius used for enlargement of Source 1 was performed, indicating its low influence. This study clearly highlights the highly enzootic situation of Cambodia regarding foot-and-mouth disease and the substantial underreporting of clinically affected villages to veterinary authorities. We propose explanations for this low notification rate, stress the importance of accurate reporting procedures and, finally, discuss the potential of capture-recapture techniques as a tool for the quantitative evaluation of animal disease surveillance systems.     

Estimating spatial and temporal variations of the reproduction number for highly pathogenic avian influenza H5N1 epidemic in Thailand

Since 2003, highly pathogenic avian influenza (HPAI) H5N1 virus has spread, causing a pandemic with serious economic consequences and public health implications. Quantitative estimates of the spread of HPAI H5N1 are needed to adapt control measures. This study aimed to estimate the variations of the reproduction number R in space and time for the HPAI H5N1 epidemic in Thailand. Transmission between sub-districts was analyzed using three different and complementary methods. Transmission of HPAI H5N1 was intense (R(t)>1) before October 2004, at which point the epidemic started to progressively fade out (R(t)<1). The spread was mainly local, with 75% of the putative distances of transmission less than 32km. The map of the mean standardized ratio of transmitting the infection (sr) showed sub-districts with a high risk of transmitting infection. Findings from this study can contribute to discussions regarding the efficacy of control measures and help target surveillance programs.     

Phytochemical and antimicrobial investigations of stilbenoids and flavonoids isolated from three species of Combretaceae

The antimicrobial activity and chemistry of the African Combretaceae has been well studied in recent years. The present study aimed to investigate the phytochemistry and antimicrobial activity of lesser known members of this family viz. C. hereroense, C. apiculatum and C. collinum. Pulverized leaves of C. collinum and C. apiculatum, and the fruit of C. hereroense were extracted with organic solvents and subjected to preparative chromatography. Seventeen phenolic constituents including four phenanthrenes from the fruit of C. hereroense and two known bibenzyls (including a combretastatin) from the leaves of C. collinum were isolated. The compounds were then subsequently tested for their antimicrobial activity against Candida albicans, Mycobacterium fortuitum, Staphylococcus aureus, Escherichia coli and Proteus vulgaris. Pinocembrin showed excellent activity against C. albicans (MIC - 6.25 μg/ml), superior to that of the positive control, fluconazole and against S. aureus (MIC - 12.5 mg/ml). The phenanthrenes (compounds 1, 2, 3 and 5) showed some activity against M. fortuitum and S. aureus with a uniform MIC of 25 μg/ml. From this study it was evident that most stilbenoids and flavonoids from the selected Combretaceae have little or no antimicrobial activity.