Molecular Epidemiology of Contagious Bovine Pleuropneumonia in Tanzania Based on Amplified Fragment Length Polymorphism and Pulsed‐field Gel Electrophoresis Analysis

The genetic diversity of 60 field strains of Mycoplasma mycoides ssp. mycoides, small colony type (M. mycoides SC), comprising 56 isolates from cattle in Tanzania, one from Kenya, two from Botswana and one from Portugal, as well as the type (PG1^T) and vaccine (T₁‐SR49) strains, was investigated. The strains were analysed for variations in the EcoRI and Csp6I restriction sites in the genomic DNA using the amplified fragment length polymorphism (AFLP) technique, and variations in the BamHI restriction sites using pulsed‐field gel electrophoresis (PFGE). Six AFLP types were detected among the analysed strains. The AFLP profiles of the type and vaccine strains were indistinguishable from each other. Indistinguishable AFLP profiles were found for 55 Tanzanian field strains, one of them isolated in 1990 and the other 54 isolated in 1998/1999, although one strain isolated in 1999 showed a different profile. Strains from different countries revealed different AFLP profiles. Six PFGE types were detected among the analysed strains, with all the 56 Tanzanian field strains displaying indistinguishable PFGE profiles. Strains from different countries revealed different PFGE profiles, and so did the type and vaccine strains. The strong genomic homogeneity among M. mycoides SC strains associated with outbreaks of contagious bovine pleuropneumonia in different regions of Tanzania suggests that the outbreaks of the disease in the 1990–99 period might have been caused by a single epidemic clone. Moreover, this study has demonstrated that AFLP and PFGE are potential tools for molecular epidemiological studies of M. mycoides SC infections.     

Potential for production of ‘mini-mussels’ in Great Belt (Denmark) evaluated on basis of actual and modeled growth of young mussels Mytilus edulis

The present study is a first step towards evaluation of the potential for line-mussel production in the Great Belt region between the Kattegat and Baltic Sea, Denmark. We present experimental results for actual growth rates of juvenile/adult mussels Mytilus edulis in suspended net bags in terms of shell length and dry weight of soft parts during extended periods (27–80 days) in the productive season in the first 6 series of field experiments, including 4 sites in Great Belt and 2 sites in Limfjorden, Denmark. Data were correlated and interpreted in terms of specific growth rate (μ, % day^?1) as a function of dry weight of soft parts (W, g) by a previously developed simple bioenergetic growth model μ = aW ^?0.34. Results were generally in good agreement with the model which assumes the prevailing average chlorophyll a concentration at field sites to essentially account for the nutrition. Our studies have shown that M. edulis can grow from settlement in spring to 30 mm in shell length in November. We therefore suggest line farming of 30 mm ‘mini-mussels’ during one growth season, recovering all equipment at the time of harvest and re-establishing it with a new population of settled mussel larvae at the beginning of the next season, thus protecting the equipment from the damaging weather of the Danish winter season. The growth behavior during the fall–winter season was recorded in an additional 7th series of mussel growth experiments on farm-ropes to show the disadvantage of this period.     

Accelerated extractions of North Atlantic cod and herring, 1520–1790

We propose the concept of Accelerated Marine Extraction to signify two periods when rapidly increasing cod (Gadus morhua, Gadidae) and herring (Clupea harengus, Clupeidae) fisheries, c.1540–1600 and c. 1730–1790, exceeded human demographic growth. Total landings vastly exceeded previous assessments and more than doubled between 1520 and 1620 from about 220,000 metric tonnes (t) to 460,000 t. Supplies of cod and herring to the European market peaked in 1788 at more than 1 million t before the unrest connected with the French Revolution brought many fisheries to a temporary halt. Accelerated Marine Extractions increased European food security at times of human demographic growth by almost doubling the supplies of fish protein per capita. While herring was the most important species by 1520, cod dominated through the period 1540–1790, and the trajectories of cod and herring extractions differed significantly. Cod landings increased almost ten-fold between 1520 and 1790, driven by strong and sustained landings in the Northwest Atlantic. Herring landings remained stable through the 16th century but declined severely through the next 150 years. However, from 1750, herring landings quadrupled, largely because of Swedish west coast fisheries. The results fundamentally shift our understanding of the scale of Atlantic fisheries in the past and underline the role of marine resources for European societies.     

Phosphoryl transfer and calcium ion occlusion in the calcium pump

A tight coupling between adenosine triphosphate (ATP) hydrolysis and vectorial ion transport has to be maintained by ATP-consuming ion pumps. We report two crystal structures of Ca2+-bound sarco(endo)plasmic reticulum Ca2+-adenosine triphosphatase (SERCA) at 2.6 and 2.9 angstrom resolution in complex with (i) a nonhydrolyzable ATP analog [adenosine (beta-gamma methylene)-triphosphate] and (ii) adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2+ ions to form an aspartyl-phosphorylated intermediate state (Ca2-E1 approximately P). The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2+, thereby preventing backflow before Ca2+ is released on the other side of the membrane.     

Mycoplasma canis and urogenital disease in dogs in Norway

Mycoplasmas identified as Mycoplasma canis were isolated from nine dogs with clinical signs of urogenital disease in Norway over a period of 20 months. Some of the dogs had been treated unsuccessfully with antibiotics, and three were euthanased as a result of severe persistent disease. Seven of the dogs had a urinary tract infection, one had chronic purulent epididymitis and one had chronic prostatitis. Overt haematuria was frequently observed among the dogs with cystitis. M canis was isolated in pure culture from seven of the dogs and in mixed culture from the other two. In three cases the mycoplasma was cultivated only from urinary sediment, and it was typically obtained in smaller numbers than would be considered indicative of a urinary tract infection. In contrast with most mycoplasmas, the M canis isolated from all the dogs grew on ordinary blood agar plates used for routine bacteriological cultivation. Specific mycoplasma media were not used and the presence of other Mycoplasma or Ureaplasma species cannot be excluded.     

Mycoplasma suipneumoniae isolated in Denmark

Though several agents may be involved in the etiology of enzootic pneumonia of pigs, recent investigations seem to indicate that the great majority of cases are caused by a Mycoplasma species — called M. suipneumoniae in Britain (Goodwin et al 1965) and M. hyopneumoniae in the U.S.A. (Maré & Switzer 1965).     

Life history characteristics of Lumbricus terrestris and effects of the veterinary antiparasitic compounds ivermectin and fenbendazole

Earthworms in pastureland may be exposed to residues of veterinary medicines excreted in the faeces of treated cattle. Possible sub-lethal effects of these drugs on life history characteristics are critical to earthworm populations, but there are no internationally accepted guidelines for the laboratory testing that is essential as a supplement to field studies. In the laboratory, Lumbricus terrestris were kept in artificial soil and offered dung collected from cattle with sustained-release boluses of ivermectin or fenbendazole, or from untreated cattle (control). Earthworms were therefore exposed to drug residues in concentrations excreted naturally by treated cattle. Furthermore, worms were exposed to the drug in the natural way, i.e. by ingestion. A matrix model based on survival and reproductive rates as functions of life-stages was used to quantify the population dynamics of L. terrestris. There were no adverse effects of either ivermectin or fenbendazole on the individual survival and growth of L. terrestris. Mature worms produced on average 2-3 cocoons per worm per month irrespective of drug treatment, and about 50% of these cocoons hatched successfully. The median time to hatching (incubation time) depended on the age of the parent worms and was significantly lower for cocoons in the ivermectin group compared to controls, as the worms became older. The incubation time varied considerably in all groups; even within a batch of cocoons produced during 1 month by one pair of worms, the period sometimes varied by more than 1 year. The intrinsic rate of natural increase (r≈0.0044 d⁻¹) was not affected by either drug treatment. The methods and the model developed in this study are suitable for long-term studies on L. terrestris and give ecologically relevant information on population dynamics. There were no negative effects of ivermectin and fenbendazole on life history characteristics of L. terrestris and it is unlikely that earthworm populations will be affected in the field following normal use of sustained-release boluses in cattle. Finally, the matrix model points to adult survival rate and cocoon viability as the most important variables to be included in future ecotoxicological tests on L. terrestris.     

Factors associated with suckling piglet average daily gain

Low piglet weight at weaning implies a loss of income for the farmer and might influence the welfare of the affected animals negatively. The objective of our cohort study was to identify risk factors in the farrowing section associated with average daily weight gain (ADG) of piglets from birth to weaning. The study was done in 3 Danish farrow-to-finish herds and included 581 sows, 277 pens, 814 farrowings, and 8241 piglets. The data were analysed with a linear mixed model where the response was ADG, and sow and litter were random effects. Piglet treatments for arthritis (-38 g per day), diarrhoea (-8 g per day) and other infections (-21 g per day) were the major infectious contributors to lower ADG. Forelimb-skin abrasions on a piglet (-5 g per day), weak pasterns of sows on concrete slats (-34 g per day), suckling a sow with poor milking 3 weeks after farrowing (-14 g per day), low birth weight (-8.4 g per day per 100 g), male compared to female (-4 g per day) also were associated with lower ADG in the suckling period.