Outbreak-specific monovalent/bivalent vaccination to control and eradicate virulent ovine footrot

Footrot is a contagious disease of small ruminants which is caused by the bacterium Dichelobacter nodosus. In its virulent form there are severe economic losses and a very significant animal welfare issue. Sheep and goats can be vaccinated for treatment and prevention of the disease. There are 10 different serogroups of D. nodosus (A–I and M) and immunity is serogroup-specific. When all 10 serogroups are presented together in a vaccine, protection persists for only a few months due to “antigenic competition”. Consequently we evaluated the use of sequential monovalent or bivalent vaccines to control/eliminate/eradicate virulent footrot in a longitudinal intervention study on 12 commercial farms in southeast Australia with flock sizes of approximately 1200–4200 sheep. Overall, virulent footrot was eradicated from 4 of the flocks, 2 of which had 2 serogroups, and the others 4 or 5 serogroups. Where there were only 1 or 2 serogroups (3 farms) the clinical response was rapid and dramatic; prevalence was reduced from 45 to 50% before vaccination to 0% (2 farms) or 0.4% (1 farm) after one round of vaccination. In the remaining 9 flocks there were more than 2 serogroups and successive bivalent vaccines were administered leading to eradication of virulent footrot on 2 farms over 4 years and control of the disease on all but 3 of the others. Of the latter farms, 1 discontinued, and 2 initially had poor response to vaccine due to misdiagnosis of serogroup ‘M’, which was previously unknown in Australia. Control was achieved after administration of a serogroup M vaccine. These results provide clear evidence for control, elimination and eradication of virulent footrot by outbreak-specific vaccination in Australia.     

PREFERENCES FOR THE NORMATIVE BASIS OF HEALTH CARE PRIORITY SETTING: SOME EVIDENCE FROM TWO COUNTRIES

The present paper concerns the criteria people would prefer for prioritising health programmes. It differs from most empirical studies as subjects were not asked about their personal preferences for programmes per se. Rather, they were asked about the principles that should guide the choice of programmes. Four different principles were framed as arguments for alternative programmes. The results from population surveys in Australia and Norway suggest that people are least supportive of the principle that decision makers should follow the stated preferences of the public. Rather, respondents expressed more support for decisions based upon health maximisation, equality and urgency. Copyright © 2012 John Wiley & Sons, Ltd.     

Effects of maximal static apnea on antioxidant defenses in trained free divers

PURPOSE: To investigate the effects of maximal static apnea on plasma antioxidant status, oxidative stress, and antioxidant enzyme activities in trained free divers. METHODS: Blood was taken from apnea-trained (Tr) and control (Con) subjects at baseline (B) and after one (A1), three (A3), and five (A5) apneas. Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of plasma (FRAP), uric acid, and bilirubin assays assessed plasma antioxidant status and malondialdehyde (MDA) quantified the oxidative stress response. The activities of erythrocyte antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were determined at baseline and after the fifth apnea. RESULTS: TEAC was significantly higher in divers versus controls after A1 (P < 0.05). A group effect of SOD activity indicated higher activity throughout the protocol in Tr (mean +/- SD; Con, 43.2 +/- 10.1 U.g Hb; Tr, 50.1 +/- 7.3 U.g Hb; P = 0.04). With no other group differences, the groups' data were combined. Apnea significantly increased SOD (B, 44.1 +/- 11.1 U.g Hb; A5, 48.1 +/- 7.5 U.g Hb; P < 0.05) and GPx activity (B, 60.5 +/- 14.9 U.g Hb; A5, 70.1 +/- 16.0 U.g Hb; P = 0.02); however, CAT activity decreased (B, 5.25 +/- 0.59 U.mg Hb; A5, 5.00 +/- 0.53 U.mg Hb; P = 0.03). MDA was unaffected by apnea (P = 0.32). CONCLUSIONS: Trained free divers have increased SOD activity during apnea; however, there is little difference in their antioxidant and oxidative stress responses compared with controls. In both groups, acute changes in antioxidant enzyme activities suggest that they may protect from excessive antioxidant depletion and oxidative stress during apnea.     

Down-regulation of urea transporters in the renal inner medulla of lithium-fed rats

BACKGROUND: Lithium is commonly used to treat bipolar psychiatric disorders but can cause reduced urine concentrating ability. METHODS: To test whether lithium alters UT-A1 or UT-B urea transporter protein abundance or UT-A1 phosphorylation, rats were fed a standard diet supplemented with LiCl for 10 or 25 days, and then compared to pair-fed control rats. To investigate another potential mechanism for decreased urea transport, inner medullary collecting duct (IMCD) suspensions from lithium-fed or control rats were incubated with 32P-orthophosphate to measure the phosphorylation of UT-A1. RESULTS: In lithium-fed rats (25 days), UT-A1 abundance was reduced to 50% of control rats in IM tip and to 25% in IM base, and UT-B abundance was reduced to 40% in IM base. Aquaporin-2 (AQP2) protein abundance was reduced in both IM regions. Vasopressin (100 pmol/L) increased UT-A1 phosphorylation in IMCD suspensions from control but not from lithium-fed rats; a higher vasopressin concentration (100 nmol/L) increased UT-A1 phosphorylation in control and lithium-fed rats. CONCLUSIONS: Decreases in UT-A1, UT-B, and AQP2 protein abundance, and/or vasopressin-stimulated phosphorylation of UT-A1, can contribute to the reduced urine concentrating ability that occurs in lithium-treated rats.     

Effects of High Intensity Training by Heart Rate or Power in Recreational Cyclists

Technological advances in interval training for cyclists have led to the development of both heart rate (HR) monitors and powermeters (PM). Despite the growing popularity of PM use, the superiority of PM-based training has not been established. The aim of the present study was to investigate the relative effectiveness of HR-based versus PM-based interval training on 20 km time trial (20km TT), lactate threshold (LT) power, and peak aerobic capacity (VO₂max) in recreational cyclists. Participants (n =20; M age=33.9, SD =13) completed a baseline 20km TT to establish their VO₂max and LT and were then randomly assigned to either HR-determined or PM-determined training sessions. Over a period of up to 5 weeks participants completed 7.2 (± 1.1) interval training sessions at their specific LT for their respective interval training method. Repeated measures analyses of variances (ANOVAs) showed that both HR-based and PM-based training groups significantly improved their LT power (F(1,16) = 28., p < 0.01, eta² = 0.63) and 20km TT time (F(1,16) = 4.92, p = 0.04, eta² = 0.24) at posttest, showing a 17 watt increase (9.8%) and a near 3-and-a-half minute improvement (7.8%) in 20km TT completion time. There were no significant group (HR vs. PM) x time (baseline vs. posttest) interactions for 20km TT completion time, LT power, or VO₂max ratings. Our results coincide with the literature supporting the effectiveness of interval training for endurance athletes. Furthermore, our findings indicate that there is no empirical evidence for the superiority of any single type of device in the implementation of interval training. This study indicates that there are no noticeable advantages to using PM to increase performance in the average recreational cyclist, suggesting that low cost HR monitor are equally capable as training devices.

Key points

• Interval training improves performance for recreational cyclists as measure by changes in lactate threshold watts and 20km time trial time
• No evidence of superiority of either heart monitor training and power meter training
• Low cost heart rate monitors are equally capable as training devices

Key words: Power, hear rate, training