Toxin types of Clostridium perfringens isolated from free-ranging,semi-domesticated reindeer in Norway

Samples of faeces were taken from 166 healthy domesticated reindeer (Rangifer tarandus tarandus) from three flocks in different reindeer husbandry districts in northern Norway and examined bacteriologically for the presence of Clostridium perfringens. The organism was isolated from 98 (59 per cent) of the reindeer. The isolates were classified into C perfringens toxin types by PCR analysis specific for the genes encoding the four major toxins (alpha, beta, epsilon and tau) and were subclassified by the detection of the genes encoding C perfringens beta2-toxin and enterotoxin. All the isolates belonged to C perfringens toxin type A. In addition, 15 of the 98 isolates were PCR-positive for the beta2-toxin gene, and two of the isolates had the the gene encoding for enterotoxin.     

The Effects of Replacing Dicalcium Phosphate with Busumbu Rock Phosphate on Performance and the Mechanical Properties of Bone in Growing Chicks

Three hundred, day-old broiler chicks, with an average initial weight of 41.8±1.79 g, were used in a 15-day study (10 birds per battery cage) to characterize their performance and fluorine status when dicalcium phosphate (DCP) was replaced by Busumbu rock phosphate (BRP) as the source of phosphorus in the chicks' ration. The treatments comprised a standard ration with BRP replacing 0, 25%, 50%, 75% or 100% of DCP. Replacing DCP with BRP significantly reduced the final weight of the chicks (p<0.01), feed intake (p<0.01), weight gains (p<0.01) and dry matter digestibility (p<0.05) but increased (p<0.05) the feed-to-gain ratio. True phosphorus absorption and the percentage of phosphorus in the tibia were not affected by increasing amounts of BRP in the diet. Increasing levels of BRP in the diet linearly reduced (p<0.01) the percentage bone ash, calcium, Ca:P ratio, ultimate breaking force, bending moment, stress, and modulus of elasticity. Leg stiffness, lameness, reduced feed intake, and a decline in general health were recorded in 10–40% of the chicks on 75% and 100% BRP, respectively. These results suggest that excessive ingestion of fluorine from the BRP caused the reduction in the chicks' performance.     

The Control of Rinderpest in Tanzania between 1997 and 1998

In January 1997, Tanzania requested international assistance against rinderpest on the grounds that the virus had probably entered the country from southern Kenya. Over the next few months, a variety of attempts were made to determine the extent of the incursion by searching for serological and clinical evidence of the whereabouts of the virus. At the clinical level, these attempts were hampered by the low virulence of the strain, and at the serological level by the lack of a baseline against which contemporary interpretations could be made. Once it became apparent that neither surveillance tool was likely to produce a rapid result, an infected area was declared on common-sense grounds and emergency vaccination was initiated. The vaccination programme had two objectives, firstly to prevent any further entry across the international border, and secondly to contain and if possible eliminate rinderpest from those districts into which it had already entered. On the few occasions that clinical rinderpest was subsequently found, it was always within this provisional infected area. Emergency vaccination campaigns within the infected area ran from January to the end of March 1997 but were halted by the onset of the long rains. At this time, seromonitoring in two districts showed that viral persistence was still theoretically possible and therefore a second round of emergency vaccination was immediately organized. Further seromonitoring then indicated a large number of villages with population antibody prevalences of over 85%. These populations were considered to have been `immunosterilized'. Although no clinical disease had been observed in them, it was decided to undertake additional vaccination in a group of districts to the south of the infected area. Serosurveillance indicated that rinderpest could have been present in a number of these districts prior to vaccination. Serosurveillance in 1998 suggested that numerous vaccinated animals had probably moved into districts outside the infected and additional vaccination areas, but did not rule out the continued presence of field infection.     

Study of the plasma pharmacokinetics and faecal excretion of the prodrug olsalazine and its metabolites after oral administration to horses

Olsalazine sodium (Dipentum*) has been used therapeutically against inflammatory bowel disease in human medicine as an alternative to sulphasalazine over the past 20 years. Bacteria in the colon split this prodrug into two molecules of the locally effective 5-aminosalicylic acid (5-ASA). Considering the potential therapeutic use in equine colitis, the pharmacokinetics of olsalazine (OLZ) after single oral administration to six horses at a dosage of 30 mg/kg was investigated. Plasma concentrations of OLZ, 5-ASA, and its main metabolite N-acetyl-5-aminosalicylic acid (Ac-5-ASA) were analysed by high-performance liquid chromatography methods. Evaluation of the plasma pharmacokinetics revealed a rapid, but low extent of absorption of OLZ (peak concentrations around 1 microg/mL at 0.5-1.5 h), and a delayed minimal absorption of 5-ASA (concentrations < 0.2 microg/mL, at 11-35 h), which is immediately metabolized to Ac-5-ASA. As indicators of the local availability in the colon, high faecal water concentrations of 5-ASA and Ac-5-ASA (mean C(max) about 300 and 130 microg/mL, respectively), but only traces of OLZ were found in faeces excreted 18-50 h after dosing. Of the administered OLZ dose 26% could be recovered from faeces, almost completely as 5-ASA and Ac-5-ASA. Routine clinical examination of the horses and assay of standard haematological and serum chemistry parameters before and after OLZ administration confirmed that a single dosage of 30 mg/kg was well tolerated. To estimate the systemic availability of 5-ASA liberated from OLZ, 5-ASA was administered i.v. at a dosage of 1.5 mg/kg to four horses and plasma concentrations of 5-ASA and Ac-5-ASA were determined. The pharmacokinetic evaluation showed a very low bioavailability of 2.4% for 5-ASA, released from orally administered OLZ. Furthermore, in an in vitro experiment, the metabolic transformation of 5-ASA to Ac-5-ASA mediated by bacteria in the caecal content of horses was determined at 38 degrees C for 31 h and compared with the metabolism data of the in vivo study. The markedly lower degree of acetylation in vitro supports the assumption that biotransformation of 5-ASA in vivo occurs not only by colonic bacteria, but also at other sites.