Use of inadequate data and methodological errors lead to a dramatic overestimation of the water footprint of Jatropha curcas

In their recent article, Gerbens-Leenes et al. (1) calculated the water footprint (WF, the amount of water required to produce 1 GJ of energy) of several bioenergy crops. One of the most remarkable findings of this study was the very high water footprint of this species, which has serious management consequences. 

However, these results are in apparent contrast with recent findings on this species. We present evidence that several errors were made by the authors when calculating the water footprint of jatropha, which has lead to a dramatic overestimation. These errors include weaknesses concerning the data used for the calculation of the water footprint, as well as flaws in the calculation method, as we demonstrate in the letter. Based on peer-reviewed data, we furthermore provide a more correct, still rough, first estimate for the water footprint of this species, which would place it amongst the more water efficient bioenergy crops. 

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Mycoplasma suis infection in suckling pigs on a Belgian farm

Mycoplasma suis (formerly known as Eperythrozoon suis) is an epicellular bacterium that affects porcine red blood cells. M. suis infections occur worldwide and are associated with weakness and anemia in suckling and weaned pigs, and reproductive disorders in sows. The present field report describes the detection of M. suis in anemic piglets originating from a Belgian farrow-to-finish herd. The herd was experiencing increased piglet mortality (16%) in the farrowing unit and had a high percentage of repeat breeders (22%). A control program using antimicrobials and hygienic and sanitary measures significantly decreased the number of clinically anemic piglets and the mortality rate in the farrowing unit. However, it did not have any significant influence on the reproductive failure of the farm. The lack of a significant effect on reproductive failure was probably due to the circulation of porcine reproductive and respiratory syndrome virus (PRRSV) on the farm

Microarray-based screening of differentially expressed genes of E. coli O157:H7 Sakai during preharvest survival on butterhead lettuce

Numerous outbreaks of Escherichia coli O157:H7 have been linked to the consumption of leafy vegetables. However, up to the present, little has been known about E. coli O157:H7's adaptive responses to survival on actively growing (and thus responsive) plants. In this study, whole genome transcriptional profiles were generated from E. coli O157:H7 cells (isolate Sakai, stx-) one hour and two days after inoculation on the leaves of growing butterhead lettuce, and compared with an inoculum control. A total of 273 genes of E. coli O157:H7 Sakai (5.04% of the whole genome) were significantly induced or repressed by at least two-fold (p < 0.01) in at least one of the analyzed time points in comparison with the control. Several E. coli O157:H7 genes associated with oxidative stress and antimicrobial resistance were upregulated, including the iron-sulfur cluster and the multiple antibiotic resistance (mar) operon, whereas the Shiga toxin virulence genes were downregulated. Nearly 40% of the genes with significantly different expression were poorly characterized genes or genes with unknown functions. These genes are of special interest for future research as they may play an important role in the pathogens' adaptation to a lifestyle on plants. In conclusion, these findings suggest that the pathogen actively interacts with the plant environment by adapting its metabolism and responding to oxidative stress

Boosaardige catarraal koorts: een wolf in schaapskleren

During recent years an increasing number of outbreaks of Malignant Catharral Fever (MCF) in cattle has been reported in several European countries. The clinical picutre also seems to be changing: the disease used to be characterized by a low morbidity and a high mortality, but large outbreaks with high morbidity and high mortality have recently been reported in several European countries, including Belgium and the Netherlands. This evolution implies that MCF becomes increasingly an economically important disease. In this article an overview is presented on the current knowledge on MCF with emphasis on epidemiology, diagnosis and preventive measures. Due to the high seroprevalence in adult sheep and the absence of protective vaccines for cattle, the conclusion of this review is that at this moment prevention of MCF in cattle mainly depends on the stringent avoidance of all contacts between sheep and cattle

Enteric pathogen survival varies substantially in irrigation water from Belgian lettuce producers

It is accepted that irrigation water is a potential carrier of enteric pathogens, such as Salmonella and E. coli O157:H7 and, therefore, a source for contamination of fresh produce. We tested this by comparing irrigation water samples taken from five different greenhouses in Belgium. The water samples were inoculated with four zoonotic strains, two Salmonella and two E. coli O157:H7 strains, and pathogen survival and growth in the water were monitored up till 14 days. The influence of water temperature and chemical water quality was evaluated, and the survival tests were also performed in water samples from which the resident aquatic microbiota had previously been eliminated by filter sterilization. The pathogen's survival differed greatly in the different irrigation waters. Three water samples contained nutrients to support important growth of the pathogens, and another enabled weaker growth. However, for all, growth was only observed in the samples that did not contain the resident aquatic microbiota. In the original waters with their specific water biota, pathogen levels declined. The same survival tendencies existed in water of 4 degrees C and 20 degrees C, although always more expressed at 20 degrees C. Low water temperatures resulted in longer pathogen survival. Remarkably, the survival capacity of two E. coli 0157:H7 strains differed, while Salmonella Thompson and Salmonella Typhimurium behaved similarly. The pathogens were also transferred to detached lettuce leaves, while suspended in two of the water samples or in a buffer. The effect of the water sample on the pathogen's fitness was also reproduced on the leaves when stored at 100% relative humidity. Inoculation of the suspension in buffer or in one of the water samples enabled epiphytic growth and survival, while the pathogen level in the other water sample decreased once loaded on the leaves. Our results show that irrigation waters from different origin may have a different capacity to transmit enteric pathogens and an important impact on the fitness of the pathogens to sustain and even grow on the leaf surface