Arcobacter, what is known and unknown about a potential foodborne zoonotic agent!

Since the introduction of the genus Arcobacter in 1991, the association of Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii with humans and animals has been clearly established. These bacteria have been detected world wide in products of animal origin and in healthy animals as well as in surface water. A fourth species Arcobacter cibarius was recently discovered on chicken carcasses. Although evidence was found for the connection of Arcobacter spp. with human and animal illness, Arcobacter spp. can be pathogens, opportunistic pathogens and commensals. Their potential as zoonotic foodborne and waterborne agents, the routes of transmission and the pathogenic mechanisms of these bacteria are largely unknown. Production of toxins or other virulence factors has not been demonstrated but adhesive and/or invasive properties were apparent. Antibiotic resistance is present in Arcobacter strains to significant levels. The tools to genetically access Arcobacter-like transformation of strains, construction of mutants are not yet available. Nor have genes (i.e. potential virulence factors) been cloned, expressed and characterized in other host organisms. Therefore those interested in the microbiology of these organisms eagerly await publication of the complete nucleotide sequence of the Arcobacter genome. The abundant presence of four Arcobacter species in foods of animal origin and the recovery of these bacteria from surface and drinking water suggest an important role of these bacteria as foodborne or waterborne agent and possibly as zoonotic agent.     

First documented Capnocytophaga canimorsus infection in a species other than humans

Capnocytophaga canimorsus was cultured from an infected, dog-inflicted bite wound in a pet rabbit. The wound was treated successfully and the rabbit recovered. To our knowledge, this is the first report of a C. canimorsus infection in a species other than humans.     

Toward metrological traceability for DNA fragment ratios in GM quantification. 1. Effect of DNA extraction methods on the quantitative determination of Bt176 corn by real-time PCR

An international CCQM-P60 pilot study involving eight national metrological institutes was organized to investigate if the quantification of genetically modified (GM) corn powder by real-time PCR was affected by the DNA extraction method applied. Four commonly used extraction methods were compared for the extraction of DNA from a GM Bt176 corn powder. The CTAB-based method yielded the highest DNA template quantity and quality. A difference in the 260 nm/230 nm absorbance ratio was observed among the different extraction methods. Real-time amplification of sequences specific for endogenous genes zein and hmg as well as transgenic sequences within the cryIA(b) gene and a fragment covering the junction between the transformed DNA and the plant genome were used to determine the GM percentage. The detection of the transgenic gene was affected by the quantity and quality of template used for the PCR reaction. The Bt176 percentages measured on diluted or purified templates were statistically different depending on the extraction method applied.     

Life history studies of the leafminer Liriomyza trifolii on susceptible and resistant cultivars of Dendranthema grandiflora

Summary The feeding, fecundity, mortality and rate of development of Liriomyza trifolii (Burgess) on 12 cultivars of Dendranthema grandiflora (Tzvel.) (Syn. Chrysanthemum morifolium (Ramat.)) were determined in no choice experiments. Number of feeding punctures, number of eggs laid and total number of larvae varied between cultivars but these characters were not strongly associated with leafminer population increase. Good indicators of host plant resistance were larval mortality, number of pupae and duration of the larval period. Of these three, larval mortality which could be as high as 98% was most suitable.Based on life history data it was predicted that Liriomyza trifolii cannot survive on the resistant cultivar Penny Lane. This prediction was verified experimentally.     

Effects of rock fragments on physical degradation of cultivated soils by rainfall

To understand better the role of rock fragments in soil and water conservation processes, the effects of rock fragments in maintaining a favourable soil structure and thus also in preventing physical degradation of tilled soils was studied. Laboratory experiments were conducted to investigate the effects of rock fragment content, rock fragment size, initial soil moisture content of the fine earth and surface rock fragment cover on soil subsidence by rainfall (i.e. change in bulk density by one or more cycles of wetting and drying). A total of 15 rainfall simulations (cumulative rainfall, 192.5 mm; mean intensity, 70 mm h⁻¹) were carried out. Before and after each rainfall application the surface elevation of a 19-cm thick plough layer was measured with a laser microrelief meter. In all experiments, the bulk density of the fine earth increased with applied rainfall volume to reach a maximum value at about 200 mm of cumulative rainfall. From the experimental results it was concluded that the subsidence rate decreased sharply for soils containing more than 0.50 kg kg⁻¹ rock fragments, irrespective of rock fragment size. Fine earth bulk densities were negatively related to rock fragment content beyond a threshold value of 0.30 kg kg⁻¹ for small rock fragments (1.7–2.7 cm) and 0.50 kg kg⁻¹ for large rock fragments (7.7 cm). Initial soil moisture content influenced subsidence only in the initial stage of the experiments, when some swelling occurred in the dry soils. Surface rock fragment cover had no significant effect on subsidence of the plough layer. Therefore, subsidence of the plough layer in these experiments appears to be mainly due to changing soil strength upon drainage rather than the result of direct transfer of kinetic energy from falling drops. The relative increase in porosity of the fine earth as well as the absolute increase in macroporosity with rock fragment content will cause deeper penetration of rainfall into the soil, resulting in water conservation. Therefore, crushing of large rock fragments into smaller ones is to be preferred over removal of rock fragments from the plough layer.     

Waterbird trapping and hunting in Lake Manzala,Egypt, with an outline of its economic significance

In the winters of 1978/79 and 1979/80, and in September and October 1980, the authors investigated the trapping and hunting of waterbirds in Lake Manzala (Egypt). It has been calculated that 98 000–162 000 waterbirds are killed annually. The number of people practising these activities is estimated at less than 2000 in a population of 35 000–40 000 fishermen. The majority of the birds are, however, taken by less than 100 men. Compared with 1930 about 30–50% fewer duck and coot are sold. This decrease is mainly caused by the decrease in numbers of pochard and tufted duck. Hunting pressure on waders was found to be extremely high. The contribution of these activities to the regional economy is reviewed and found to be insignificant. A number of conservation measures are recommended.     

Spatial and temporal variation of muddy floods in central Belgium, off-site impacts and potential control measures

Numerous villages in the European loess belt are confronted with floods caused by runoff from agricultural land. Seventy-nine percent of the municipalities in central Belgium experienced at least one muddy flood during the last decade. Of these flooded municipalities, 22% have been affected more than 10 times during this period. Twenty municipalities have been selected for a detailed analysis. A database of 367 locations affected by muddy floods has been compiled, and the connectivity between cultivated areas and inhabited zones could be assessed for 100 flooded locations. Roads and drainage network facilitate runoff transfer between cultivated and inhabited areas in 64% of cases. Three types of areas producing muddy floods have been identified: hillslopes (1–30 ha) without thalweg where runoff is generally dominated by sheet flow; small catchments (10–300 ha) characterised by runoff concentration in the thalweg and medium catchments (100–300 ha) with multiple thalwegs dominated by concentrated runoff. About 90% of muddy floods are generated on hillslopes and in small catchments. A critical area–slope threshold for triggering muddy floods has been computed for hillslopes. A logistic regression shows that muddy floods are generated in small and medium catchments with 99% probability after 43 mm rainfall. Rainfall depths required to trigger muddy floods are lower in May and June (25 ±12 mm) than between July and September (46 ± 20 mm), because of different surface conditions (crusting, roughness and crop cover). Each year, muddy floods lead to a total societal cost of 16 × 10⁶–172 × 10⁶ € in central Belgium, depending on the extent and intensity of thunderstorms and monetary values damaged. Recent datasets suggest that the phenomenon is becoming more frequent in central Belgium, because of land consolidation, urban sprawl and expansion of row crops, sown in spring, at the expense of winter cereals. The huge costs induced by muddy floods justify the installation of erosion control measures. It is suggested to install a grassed buffer strip at the downslope edge of cultivated hillslopes to protect houses and roads. In small and medium catchments, it is preferred to install a grassed waterway and earthen dams in the thalweg.     

The other side of the coin: A case study on the impact of financial autonomy on irrigation management performance in the Philippines

The paper assesses the impact of the removal of operating subsidies to the Philippine National Irrigation Administration on the management performance of a small canal irrigation system in Southern Luzon. It shows that in this case the creation of financial autonomy of the agency did not fully engender the often assumed positive effects regarding both accountability relationships and irrigation management performance. The conclusions specify a number of issues related to the theory of financial autonomy which require further study.