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Biomedical subjects

G Gettinby

Publications and source records attributed to G Gettinby.

At least 19 recordsLinked to original sources

Examination of serum total IgG1 concentration in atopic and non-atopic dogs.

In this study, serum immunoglobulin G1 (IgG1) concentrations were examined in atopic and non-atopic dogs receiving different levels of parasite control. Significantly lower serum total IgG1 concentrations were found in non-atopic dogs receiving stringent parasite control than in atopic dogs or non-atopic dogs receiving less stringent parasite control. Examination of serum total IgG1 concentrations of atopic dogs after six months of allergen specific immunotherapy (ASIT) showed a significant increase in serum total IgG1 concentrations. It is proposed that serum total IgG1 concentrations are affected by parasitism, atopic dermatitis and ASIT.

Allergens↗

Potential use of vaccination in cattle or badgers to control bovine tuberculosis.

The application of regular herd testing to identify and remove infected animals has proved to be a highly successful method of controlling bovine tuberculosis (TB) in many parts of the world. However, in some countries, notably the United Kingdom, Ireland and New Zealand, the disease has continued to pose a significant problem, despite intensive herd testing. Persistence of disease in these countries is associated with the presence of wildlife reservoirs of infection. Attempts to control bovine TB by culling of wildlife have been, at best, only partially successful and have proved difficult to sustain. This has led to considering of vaccination either of wildlife or cattle as a potential control measure. However, there are a number of obstacles that need to be overcome before vaccination can be considered a practical option. Vaccine efficacy, methods used for vaccine delivery in wildlife, potential interference of vaccination with diagnostic tests for cattle and appropriate design of field trials are among the issues that need to be addressed.

Animals↗

Identifying epidemiological factors affecting sea lice Lepeophtheirus salmonis abundance on Scottish salmon farms using general linear models.

The variation in Lepeophtheirus salmonis sea lice numbers across 40 Scottish salmon farm sites during 1996 to 2000 was analysed using mean mobile abundance for 3 important 6 mo periods within the production cycle. Using statistical regression techniques, over 20 management and environmental variables suspected to have an effect on controlling lice populations were investigated as potential risk factors. The findings and models developed provide a picture of mobile L. salmonis infestation patterns on Scottish farm sites collectively. The results identified level of treatment, type of treatment, cage volume, current speed, loch flushing time and sea lice levels in the preceding 6 mo period to be key explanatory factors. Factors such as stocking density, site biomass, water temperature and the presence of neighbours, previously cited to be important correlates of sea lice risk from analysis of individual sites over time, were not found to be important. Variation in mobile abundance in the first half of the second year of production could be adequately explained (adjusted R2 between 55 and 72%) by the recorded data, suggesting that there is scope for management to control L. salmonis abundance, though much of the variation remains unexplained.

Animals↗

Studies of serum total immunoglobulin E concentrations in atopic and non-atopic dogs.

The serum total immunoglobulin E (IgE) concentrations of two groups of atopic dogs and three groups of non-atopic dogs were compared. There was a wide range of concentrations with a high degree of overlap between the groups. The serum total IgE concentrations of a group of 15 non-atopic racing greyhounds were significantly higher than those of all the other groups. Atopic and non-atopic dogs receiving stringent parasite control treatments could not be differentiated on the basis of their serum total IgE concentrations. In the non-atopic dogs there was no correlation between their serum total IgE concentrations and the number of allergen-specific positive results obtained in an ELISA, or between their serum total IgE concentrations and their age.

Aging↗

A comparison of epidemiological patterns of salmon lice, Lepeophtheirus salmonis, infections on farmed Atlantic salmon, Salmo salar L., in Norway and Scotland.

This paper examines two large national data sets collected over several years and contrasts the patterns of sea lice, Lepeophtheirus salmonis (Krøyer, 1837), infections, the use of treatments and the occurrence of chalimus peaks between Norwegian and Scottish farms. Infection levels in Scotland were significantly higher in general over the period under study. For the chalimus stage group in the first quarter of the year, Norwegian mean abundance stayed below 10 lice per m2 while Scottish means reached 45 lice per m2 of fish skin per m3 of water. Both countries had more chalimus in summer than at other times of year, but in the last 3 months of the year Scottish fish had, on average, two to four times as many chalimus as Norwegian fish. Peaks of chalimus abundance were more frequent in Scotland, particularly in winter, but the most prominent peaks occurred in summer in both countries. In Scotland a marked mid-year build-up of mobile pre-adult and adult stages was seen, and both countries showed a tendency for mobile counts on the second year fish to increase towards the end of the year. Scottish fish carried, on average, three times as many mobile lice per m2 of skin as Norwegian fish in the last 3 months of the year. The difference in lice loads was reflected in the greater use of veterinary medicines on Scottish farms. The higher infection levels in Scotland may be due to shallower and more enclosed water bodies used for farming, smaller and shallower pens, differences in sea water temperatures or in access to appropriate medication. The results highlight the importance of ensuring that effective veterinary medicines are available in the UK for the control of infection.

Animals↗

In vitro and ex vivo effects of the phosphodiesterase 4 inhibitor, rolipram, on thromboxane production in equine blood.

Phosphodiesterase 4 (PDE4) inhibitors have been shown to inhibit equine neutrophil function in vitro and may be of benefit in recurrent airway obstruction (RAO), an allergy-based respiratory disease characterized by inflammatory cell recruitment and activation within the lungs following exposure of susceptible horses to allergens in mouldy hay. The aim of this study was to evaluate the inhibitory effects of the PDE4 inhibitor, rolipram, in an in vitro assay of thromboxane (Tx) production. The assay was then used to monitor the activity of this compound in vivo in normal and RAO-affected horses. Rolipram and the structurally distinct PDE4 inhibitor, denbufylline, attenuated both lipopolysaccharide (LPS)-induced and unstimulated Tx production in blood from normal horses. Thromboxane production appeared to involve a calcium-dependent interaction between leucocytes and platelets (LPS-induced Tx production = 2.3 +/- 0.4, 4.5 +/- 1.1 and 20.8 +/- 3.6 ng/mL for platelets, leucocytes and blood, respectively) and rolipram-inhibited Tx production via an effect on leucocytes. Inhibition of ex vivo LPS induced Tx production was detected after intravenous administration of rolipram (5 microg/kg) to normal ponies. This dose did not significantly affect either lung function or neutrophil accumulation when administered to three horses with clinical signs of RAO. This study suggests that inhibition of Tx production in equine blood can be used to measure PDE4 activity. However, PDE4 inhibitors with improved therapeutic profiles are required for evaluation in RAO.

3',5'-Cyclic-AMP Phosphodiesterases↗

Veterinary Products Committee working group report on feline and canine vaccination.

* The working group was set up by the Veterinary Products Committee in response to current concern in both the public domain and in the scientific community about possible health risks related to the routine vaccination of cats and dogs. The working group concluded that vaccination plays a very valuable role in the prevention and control of the major infectious diseases in cats and dogs. Although adverse reactions to vaccination, including lack of efficacy, occasionally occur, the working group concluded that the overall risk/benefit analysis strongly supports their continued use. * Although for some diseases there is evidence of a longer duration of immunity following vaccination than the one year which is typically recommended on the product literature, there is currently insufficient information to propose revaccination intervals other than those proposed by the manufacturer and approved by the regulatory process. * Notwithstanding this, in view of the occasional occurrence of adverse reactions, the working group recommends that the product literature indicates that the regime for booster vaccinations is based on a minimum duration of immunity rather than a maximum. The working group further recommends that the product literature should state that a risk/benefit assessment should be made for each individual animal by the veterinary surgeon in consultation with the owner with respect to the necessity for each vaccine and the frequency of its use. * The evidence suggests that cats appear to be susceptible to the occasional development of sarcomas at sites of injection and there is some further evidence to suggest that, although other products may be involved, this may be more associated with the use of vaccines containing aluminium-based adjuvants. The working group therefore recommends that a generic warning to this effect should appear on the product literature for all feline vaccines administered by injection. The working group also highlighted the need for professional and educational bodies in the UK to bring to the attention of veterinary practitioners appropriate methods for prevention, diagnosis and treatment of this serious condition. * The working group considered in depth the monitoring of adverse reactions, including the advantages and disadvantages of surveillance schemes. A range of options for carrying out further epidemiological (analytical) studies was also considered. However, the working group emphasised that surveillance schemes, and the UK Veterinary Medicines Directorate (VMD) Suspected Adverse Reaction (SAR) Surveillance Scheme in particular, provided a very valuable resource. The large database within the VMD scheme (collected since 1985) was analysed as part of this report. Figures were derived in terms of incidence (reporting rate) of certain clinical signs per 10,000 doses, and risk factors as identified by statistical analysis. However, due to a number of constraints, the analysis was not fully comprehensive and the interaction of possible risk factors was not determined. * Product-related control charts were developed in order to detect changes in incidence rates of adverse reactions (per 10,000 doses sold) both within and between different vaccines. Such charts provide a powerful way to detect changing trends in incidence and, when used in conjunction with product characteristics, they may identify possible causes. In general, the data showed that the incidence of adverse reactions to cat and dog vaccines per 10,000 doses of product sold was relatively low. Although under-reporting is a feature of such surveillance schemes, it does appear that, overall, vaccination of cats and dogs should be considered safe and effective. * Finally, the working group was conscious, while preparing this report, of the extensive media coverage that has been given to the issue of the safety of human vaccines, in particular the mumps, measles and rubella (MMR) vaccine. The working group emphasises that the conclusions and recommendations included in this report relate only to the vaccines used in cats and dogs. The issues identified are specific to the diseases and species examined and no attempt should be made to draw analogous conclusions in relation to vaccines administered to humans.

Animal Welfare↗

The efficacy of Salenvac, a Salmonella enterica subsp. Enterica serotype Enteritidis iron-restricted bacterin vaccine, in laying chickens.

The protective effect of two vaccination regimes using Salenvac, a commercially available iron-restricted Salmonella enterica subsp. Enterica serotype Enteritidis PT4 bacterin vaccine, was verified in laying birds. Immunization was intramuscular at 1 day old and again at 4 weeks of age (V2), or at 1 day and 4 weeks with a third dose at 18 weeks of age (V3). Challenge S. Enteritidis (5 to 7.5); x 10(7) colony forming units) was given intravenously at 8, 17, 23, 30 and 59 weeks of age. For all age groups, both vaccination regimes reduced significantly the number of tissues and faecal samples that were culture positive for the challenge strain. For laying birds, fewer eggs (P < 0.001) were culture positive for S. Enteritidis after challenge from vaccinated laying birds (56/439 batches of eggs) than unvaccinated birds (99/252 batches). The data give compelling evidence that the vaccine is efficacious and may contribute to the reduction of layer infection and egg contamination.

Animals↗

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya.

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.

Age Factors↗

Sentinel practice-based survey of the management and health of horses in northern Britain.

Details of the management, feeding, level of activity and routine health care of horses in Scotland and the five northernmost counties in England were recorded through a stratified random sample of horse owners who had responded to a previous survey. Sixty-eight per cent of the horses were kept where their owners resided, and 32 per cent were kept away from the owner's home. More than 99 per cent were turned out to grazing for at least part of the year and 81 per cent were stabled for at least part of the time, most commonly bedded on straw (50 per cent) or shavings (34 per cent). Hay was fed to 87 per cent, sugar beet pulp to 64 per cent and commercially prepared concentrate mixes to 60 per cent of the horses. Hacking was the most popular activity (52 per cent of horses) followed by riding/pony club events (28 per cent) and showing (21 per cent). The majority of the horses were involved in more than one activity. There were an estimated 0.88 veterinary visits per horse per year and 29 per cent of the horses were reported to suffer from at least one permanent or recurrent health disorder. The median annual numbers of administrations of vaccines (influenza and tetanus) and anthelmintics were one and seven respectively per horse, and each horse was shod a median seven times. There were significant differences in the management of horses kept in different types of premises and in areas of different human population density.

Animal Feed↗

Serum alpha-tocopherol concentrations in German shepherd dogs with chronic degenerative radiculomyelopathy.

The concentration of serum alpha-tocopherol was measured in German shepherd dogs with chronic degenerative radiculomyopathy, and in German shepherd dogs and dogs of other breeds unaffected by the condition. The mean concentration was significantly higher in German shepherd dogs with the condition than in other breeds of dog unaffected by it, but it was not significantly higher than in unaffected German shepherd dogs. Estimates of components of variance indicated that the concentration varied more widely in individual affected dogs than in unaffected dogs, irrespective of breed. These results suggest that chronic degenerative radiculomyopathy in German shepherd dogs is unlikely to be due to uncomplicated vitamin E deficiency.

Animals↗

Correlations of measurements of subclinical claw horn lesions in dairy cattle.

Measurements were made of the extent of sole and white line lesions on the claws of 115 Holstein-Friesian cows on at least three and at most 16 occasions, and some cows were followed up to their third lactation. All the measurements were made between 12 weeks before calving and 45 weeks after calving. In total, 1016 repeated observations were made. Correlations were calculated between pairs of claws, between types of lesion (sole and white line), and between pairs of the different measurements (number of lesions, proportion of the claw affected, maximum severity score and proportion of the claw affected weighted for severity). The outer hind claws had the greatest extent of lesions of both types. Spearman correlation coefficients and confidence intervals measured the strength of the association. All the associations between claws were positive, suggesting that the lesions did not occur in isolation. Sole and white line lesions were not associated at individual observation points. Lesions on the left and right claws were markedly similar, except for sole lesions on the two inner hind claws, and for white line lesions on the two outer hind claws.

Animal Husbandry↗

A quantitative risk assessment for the occurrence of campylobacter in chickens at the point of slaughter.

A quantitative risk assessment model investigating the risk of human infection with campylobacter from the consumption of chicken meat/products is currently being formulated. Here such an approach is used to evaluate the probability that a random bird, selected at slaughter from Great Britain's national poultry flock, will be campylobacter-positive. This is determined from the probability that a flock chosen at random contains at least one colonized bird and the within-flock prevalence of such a flock at slaughter. The model indicates that the probability bird chosen at random being campylobacter-positive at slaughter is 0.53. This probability value has associated uncertainty, the 5th percentile being 0.51 and the 95th percentile 0.55. The model predicts that delaying the age at first exposure to campylobacter can have a significant impact on reducing the probability of a bird being campylobacter-positive at slaughter. However, implementation of current biosecurity methods makes this difficult to achieve.

Animals↗

Development of a technique for the in vivo assessment of flatulence in dogs.

OBJECTIVE: To develop a noninvasive method for the in vivo assessment of flatulence in dogs. ANIMALS: 8 adult dogs. PROCEDURE: Rectal gases were collected via a perforated tube held close to each dog's anus and attached to a monitoring pump fitted with a sensor that recorded hydrogen sulfide concentrations every 20 seconds. Patterns of flatulence were monitored for 14 hours after feeding on 4 days, and within- and between-dog variation was assessed over 4 hours on 4 consecutive days. Rate of hydrogen sulfide production (flatulence index) and frequency and number of emissions were evaluated as potential indicators of flatus characteristics. An odor judge assigned an odor rating to each flatulence episode, and the relationship between that rating and hydrogen sulfide concentration was determined. RESULTS: Flatulence patterns varied within and between dogs. Variation was most pronounced for flatulence index; mean coefficients of variance within dogs over time and between dogs on each day were 75 and 103%, respectively. Flatus with hydrogen sulfide concentrations > 1 parts per million could be detected by the odor judge, and severity of malodor was highly correlated with hydrogen sulfide concentration. Odor ratings were accurately predicted by use of the equation 1.51 X hydrogen sulfide concentration(0.28). CONCLUSIONS AND CLINICAL RELEVANCE: The technique described in this report appears to provide sensitive, reliable, and relevant data and will enable further studies of the factors that influence flatulence in dogs. Use of this technique also has the potential to aid in investigations of colonic physiology and pathology.

Animals↗

Using a Bayesian belief network to aid differential diagnosis of tropical bovine diseases.

The examination of presenting signs has always played an important role in the diagnosis of diseases in animal populations. In the case of diseases of tropical cattle, such expertise is often scarce and confined to those experts with many years of experience. To capture, conserve and disseminate such valuable expert knowledge remains a key challenge to the application of knowledge-based systems in veterinary medicine. In this communication, we explore the use of a Bayesian belief network to quantify expert opinion with a view to estimating the likelihood of various diseases in the presence and absence of certain signs. Information was elicited from a panel of 44 experienced veterinarians to provide the response matrix of 27 signs associated with 20 commonly occurring diseases in sub-Saharan cattle. Using this prior information, estimates of the probability of certain signs occurring with each disease were calculated from which the Bayesian belief network was able to propagate the posterior probability of each of the diseases based on the observed signs. The method as an aid in making diagnosis is discussed. It is recognised that such an approach is but one strand in the process of arriving at a diagnosis. For ease of use and accessibility, the approach has been converted into the software program CaDDiS (Cattle Disease Diagnosis System) which is available for consultation on the World Wide Web.

Animals↗

Pathogenesis and diagnosis of infections with Mycobacterium bovis in cattle. Independent Scientific Group on Cattle TB.

In last week's Veterinary Record, members of the Independent Scientific Group on Cattle TB discussed the approach they are adopting in attempting to develop sustainable strategies for controlling bovine tuberculosis in cattle (VR, February 19, pp 207-210). In this second, complementary article, they consider the extent to which efforts to control the disease may be constrained by limitations in current testing procedures.

Animals↗

Bovine tuberculosis: towards a future control strategy.

The Independent Scientific Group on Cattle TB was appointed by the Government in 1998 to implement and develop the research recommendations of the 1997 Krebs report on bovine tuberculosis in cattle and badgers. In this article, members of the group discuss the approach they are adopting in attempting to ensure that future control strategies are scientifically based. In a second article, to be published in next week's Veterinary Record, the group will consider the extent to which efforts to control the disease in cattle may be constrained by limitations in current testing procedures.

Animals↗