Antifungal agents of use in animal health--practical applications

The purpose of this paper is to provide an overview of antifungal agents currently in use in veterinary medicine. The practical applications and the therapeutic regimens that have proved successful in the treatment and prevention of fungal infections in dogs and cats, cattle and sheep, horse, pig, poultry and other birds, rodents, rabbits and fur animals are summarized.     

Efficacy of non-acaricidal containing otic preparations in the treatment of otoacariasis in dogs and cats

Eighty-nine cats and 38 dogs naturally infested with the ear mite Otodectes cynotis were randomly allocated into two treatment groups. One group was treated with a product containing miconazole nitrate, polymyxin B sulphate and prednisolone acetate, the other with a combination of diethanolamine fusidate, framycetin sulphate, nystatin and prednisolone. The treatment (five drops in each ear) was applied twice daily for 14 days, and its efficacy was evaluated on days 7, 14 and 21 on the basis of an otoscopic examination of the external ear canal, a microscopical examination of scrapings for the presence of ear mites and clinical signs of pruritus, pain, erythema and/or exudate. Both treatments were highly effective, and there were no significant differences between the two products, either in efficacy or in the clinical improvements observed. Apart from an allergic reaction in one cat treated with the second product, no adverse effects were observed.     

Effects of ketanserin on hypergranulation tissue formation, infection, and healing of equine lower limb wounds

The objective of this multicentre, randomized, controlled field study was to determine the efficacy of ketanserin gel in preventing exuberant granulation tissue formation (hypergranulation) and infection in equine lower limb wounds. Horses and ponies (n = 481) with naturally occurring wounds were randomized to either topical treatment with ketanserin gel (n = 242) or a positive control (Belgium, Germany: ethacridin lactate solution, n = 120; France, United Kingdom: malic, benzoic, and salicylic acid [MBS] cream, n = 119). Treatment continued until the wound healed (success), formed hypergranulation tissue (failure), or became infected (failure). Treatment was terminated after 6 months in all remaining animals. Ketanserin was successful in 88% of cases. Wounds treated with ketanserin were 2 and 5 times more likely to heal successfully than were those treated with MBS or ethacridin lactate, respectively. Ketanserin gel is thus more effective than these standard treatments in preventing hypergranulation tissue and infection of equine lower limb wounds.     

The value of a bulk-tank milk ELISA and individual serological and faecal examination for diagnosing (sub)clinical Dictyocaulus viviparus infection in dairy cows

To test the value of a recently developed bulk-tank milk (BTM) ELISA for diagnosing (sub)clinical Dictyocaulus viviparus infection in lactating dairy herds under field conditions, bulk milk samples were collected from farms with or without clinical symptoms suspected to be caused by lungworm infection. Results of the BTM ELISA were compared against individual examinations for lungworm larvae in faeces and lungworm antibodies in serum from up to 20 heifers (parity 1) and up to 20 cows (parity ≥ 2) on the same farms. This also allowed, for the first time, to examine the value of individual faecal and serological examinations in the diagnosis of (sub)clinical lungworm infections. In total, 33 farms participated. Of these, 16 reported clinical symptoms possibly related to lungworm infection (defined as a suspected positive clinical status or CS(+)) and 17 reported having no such symptoms (CS(-)). In total, 503 heifers and 649 cows were sampled. Of all faeces samples positive for lungworm larvae, 94 were from heifers (18.9% of all heifers) and 75 from cows (11.7% of all cows) (P<0.001). Of all sera positive for lungworm antibodies, 130 were from heifers (26.1% of all heifers) and 113 from cows (17.5% of all cows) (P<0.001). Of the CS(-) farms 41% had at least one heifer or cow shedding larvae and 71% had at least one seropositive heifer or cow. Of the CS(+) farms this was 81% and 94%, respectively. There were only 4 farms, all CS(-), where none of the animals were found shedding larvae and all animals tested seronegative. This implies that on 76% of the CS(-) farms lungworm infection circulated unnoticed. On all CS(+) farms the suspicion that lungworm caused the respiratory symptoms was confirmed by the individual faecal and serological examinations, whereas the BTM ELISA confirmed presence of lungworm on half of the CS(+) farms. The latter in particular occurred on farms with the more severe outbreaks. Overall, of 32 available BTM samples 10 tested positive (8 of 15 CS(+) and 2 of 17 CS(-) farms). For diagnosing suspected lungworm disease it was concluded that testing a BTM sample might suffice in case of moderate to severe outbreaks. However, in case of a mild outbreak with just a few animals coughing, examining individual animals has to be preferred over testing a BTM sample. The likelihood to detect lungworm infection is higher if heifers are sampled compared to cows. Sensitivity of the BTM ELISA was 35.7% if the presence of at least one seropositive and/or one larvae shedding animal in the herd was used to define lungworm positive farms. On average, at least 30% of the herd had to be seropositive before the BTM ELISA was found positive for lungworm antibodies. Results indicate that the BTM ELISA in its current form does not appear to be suitable for surveys on the prevalence of lungworm presence on farms. However, this BTM ELISA might be used in large-scale surveys to detect, for instance, annual changes in percentage positive farms, as long as it is recognized that positivity is more closely related to incidence of lungworm disease than to prevalence of lungworm infection.     

Development of Purkinje cells in the ovine brain

Purkinje cells are involved in many vital functions within the body. Twenty ovine fetuses ranging from 2 to 5 months of gestation, two lambs in the first week after birth and three adult sheep were studied. Sections of the cerebellum were stained with haematoxylin and eosin, cresyl violet and Klüver-Barrera. This study indicates that Purkinje cells began to appear after the 15(th) week of gestation. There were varying degrees of development of Purkinje cells in different zones of the cerebellum. Our findings in sheep fetuses suggest that the maturation of Purkinje cells starts in the caudal regions of the cerebellum and that the process begins in the vermis before it does in the cerebellar hemispheres. The alignment of Purkinje cells was found to be very regular in the caudal regions of the cerebellum. A partial absence of Purkinje cells in the rostral regions of the cerebellum was observed in both sheep fetuses and adult sheep. In the first post-natal week, some ectopic Purkinje cells were found in the white matter of the cerebellum.     

Effect of mitratapide on body composition, body measurements and glucose tolerance in obese Beagles

The objective of this study was to confirm that weight loss after treatment with mitratapide (Yarvitan®) is loss of adipose tissue. Obese dogs were treated with the recommended treatment schedule of mitratapide. Dual-energy X-ray absorptiometry (DEXA) was done before and after the treatment schedule. Body weight, feed consumption and pelvic circumference were recorded and a glucose tolerance test was performed. Dual-energy X-ray absorptiometry measurements showed an impressive loss of fat tissue, corresponding to a mean loss of approximately 41.6% of the body fat mass recorded before treatment. After treatment with mitratapide, the mean body fat percentage had returned within the normal range. At the end of the study, the dogs had lost on average 14.2% of their body weight and 15.2% of their pelvic circumference compared to baseline. The results also suggest that losing weight with mitratapide might help to reverse insulin resistance.     

Polyunsaturated Fatty Acids of Marine Macroalgae: Potential for Nutritional and Pharmaceutical Applications

As mammals are unable to synthesize essential polyunsaturated fatty acids (PUFA), these compounds need to be taken in through diet. Nowadays, obtaining essential PUFA in diet is becoming increasingly difficult; therefore this work investigated the suitability of using macroalgae as novel dietary sources of PUFA. Hence, 17 macroalgal species from three different phyla (Chlorophyta, Phaeophyta and Rhodophyta) were analyzed and their fatty acid methyl esters (FAME) profile was assessed. Each phylum presented a characteristic fatty acid signature as evidenced by clustering of PUFA profiles of algae belonging to the same phylum in a Principal Components Analysis. The major PUFA detected in all phyla were C₁₈ and C₂₀, namely linoleic, arachidonic and eicosapentaenoic acids. The obtained data showed that rhodophytes and phaeophytes have higher concentrations of PUFA, particularly from the n-3 series, thereby being a better source of these compounds. Moreover, rhodophytes and phaeophytes presented “healthier” ∑n-6/∑n-3 and PUFA/saturated fatty acid ratios than chlorophytes. Ulva was an exception within the Chlorophyta, as it presented high concentrations of n-3 PUFA, α-linolenic acid in particular. In conclusion, macroalgae can be considered as a potential source for large-scale production of essential PUFA with wide applications in the nutraceutical and pharmacological industries.     

Prevalence and risk factors for Coxiella burnetii (Q fever) in Dutch dairy cattle herds based on bulk tank milk testing

Despite cattle herds can harbor Coxiella burnetii, risk factors for C. burnetii presence in dairy cattle herds are largely unknown. Therefore, C. burnetii herd prevalence and risk factors for bulk tank milk (BTM) positivity were investigated. In this cross-sectional study, a questionnaire was filled out by the farmer and BTM from 301 farms was tested by ELISA for presence of C. burnetii antibodies and PCR for presence of C. burnetii DNA. Risk factors were identified by univariable and multivariable logistic regression analyses. Antibodies to C. burnetii were detected in 81.6% (CI: 77.2–85.9) and C. burnetii DNA in 18.8% (CI: 14.4–23.1) of the BTM samples. Herd size (OR = 1.1 per 10 cows), cleaning the bedding of the cubicles at most every other day (OR = 2.8) and purchase of cattle from at least two addresses (OR = 3.1) showed a significant and positive association with ELISA positivity and use of an automatic milking system a negative association (OR = 0.3). Risk factors for PCR positivity were purchase of cattle from at least two delivery addresses (OR = 3.2), presence of cows with ticks (OR = 2.0), use of an automatic milking system (OR = 0.2) and presence of goats or sheep on the farm (OR = 0.4). Biosecurity and general hygiene seem associated with introduction and spread of C. burnetii in dairy herds.     

A world soils and terrain digital database (SOTER) — An improved assessment of land resources

The soil is a natural resource, non renewable in the short term or very difficult to renew and expensive either to reclaim or to improve following erosion, physical degradation or chemical pollution. The increasing pressure on land and water resources, leading to degradation and pollution of those resources, and a reduced productive capacity calls for a system which can store detailed information on natural resources of all kinds in such a way that these data can be accessed, combined and analyzed from the point of view of potential use, in relation to food requirements, environmental impact and conservation. Such a system is a prerequisite for policy formulation, development planning at all levels, efficient use of both internal and external resources, and for implementation of development programmes.

In a typical case such a system would consist of:

1. (1) A computerised database containing all available information on topography, soils, climate, vegetation and land use. It should be complemented with compatible databases of socio-economic factors.

2. (2) Geographical Information System or GIS, which links each item of information to its precise geographical location, but which can display each type of information as a separate layer, or overlay.

3. (3) A set of crop yield models which can calculate the level of production which could be obtained from each and any combination of soil and climate in the region or country, at a number of different input levels or management systems.

4. (4) Various environmental impact models, which, for example, allow the calculation of rates of erosion for a given land unit, use, and production system.

Development of computerized natural resource inventory and land evaluation systems especially for use in developing countries has been carried out by FAO since the early nineteen-seventies, notably under the Agro-Ecological Zones programme. In 1987, the International Soil Reference and Information Centre (ISRIC), based in Wageningen, the Netherlands, undertook at the request of UNEP and in close cooperation with the ISSS, FAO and the Land Resources Research Centre in Canada, to develop a Methodology for a World Soils and Terrain Digital Database (SOTER).

This land resource information system was tested in three pilot areas involving five countries (Argentina, Brazil, Uruguay, USA and Canada), using local data and training national staff in operation. Though further up-grading and improvement will continue, this system can now be established as an almost routine operation which mainly involves the provision of equipment, and training.

Most developing countries are quite acutely aware of the need, and many are already attempting to establish computerised natural resource databases of one kind or another. Furthermore, all donors and aid agencies, particularly those such as the World Bank, which seek comprehensive solutions, will TIF become aware that such systems are an essential tool for development, and are also very cheap in comparative terms.

A long term commitment from these agencies is needed so that SOTER can rapidly provide the key soil and terrain attributes, which are needed to assess the potential productivity of the land, the status, risk and rate of soil degradation, to develop action to conserve or rehabilitate the land, and to improve our understanding in global change.