0.4% Dimeticone spray,a novel physically acting household treatment for control of cat fleas

The cat flea, Ctenocephalides felis, is the most important ectoparasite of cats and dogs worldwide as a cause of irritation and health problems. Most products to control these pests in the household environment rely upon a combination of neurotoxic insecticides and insect growth regulators to inhibit development of flea eggs and larvae into adults. However, some of these are affected by problems of insecticide resistance as well as public concerns about their potential for toxicity in domestic use. Heavy synthetic oils, like the siloxane dimeticone, are currently widely used to treat human ectoparasite infestations, acting by a physical mode of action, and have been used in a variety of presentations for killing all life stages of fleas. We have investigated the activity of low concentrations of high molecular weight dimeticone in a volatile silicone base for ability to immobilise flea life stages without asphyxiating them. We found that cat flea adults and larvae were immobilised by a surface film of dimeticone that inhibited movement of cuticular joints, apparently forming an effective sticky trap. When cocoons were treated the fleas continued to develop within the pupae but failed to emerge. An aerosol spray incorporating 0.4% concentration of dimeticone, for use as a residual household treatment, showed no significant difference in knock down capability compared with that of a widely used pyriproxifen/permethrin spray in a repeat challenge test, with effects persisting to inhibit adult flea emergence in the test arena area for more than 3 weeks after application.     

Age- and position-related heterogeneity of equine tendon extracellular matrix composition

The digital flexor tendons of the neonate and adult horse have been compared with respect to variation in extracellular matrix composition along their length. Two pepsin-sensitive, acetic acid soluble proteins, molecular weight (Mr) 52 kD (np 52) and Mr 54 kD (np 54), were prominent throughout the length of neonatal tendons. In adult tendon, np 52 and np 54 were less abundant and restricted to the cannon (metacarpal) region. In contrast, a single pepsin- and collagenase-resistant protein of Mr 55 kD (fp 55) was exclusive to the fetlock (metacarpophalangeal joint) region regardless of age, although more distinct in the adult. Pepsin extracted fp 55 precipitated at 2.0 M sodium chloride: 0.5 M acetic acid and was further purified to homogeneity by bacterial collagenase digestion. Analysis of fp 55 amino acid composition revealed the presence of a large proportion of glycine residues (379 of 1001), suggesting a possible homology with the collagen family. These data demonstrate that the composition of equine digital flexor tendons varies with age, is heterogeneous along its length, and suggests that variation in tendon extracellular matrix composition is influenced by functional requirements.     

Cryopreservation ofTheileria-infected lymphoblastoid cells with functional assessment of viability

Summary Bovine lymphoblastoid cell cultures infected withTheileria annulata were frozen to −60°C in a programmable cooling apparatus using continuous cooling rates of 1°C/min, 10°C/min and 120°C/min and a two-step cooling rate with an equilibration period of 20 min at −30°C. The cryopreservative was DMSO at concentrations of 5, 10 and 15%. Aliquots of cryopreserved material were stored in the vapour phase of a liquid nitrogen refrigerator and resuscitated by rapid thawing in a 40°C water bath. The efficiency of the freezing methods was compared by assessing the viability and plating efficiency of cells after resuscitation, dilution and equilibration in cell culture medium. A significant correlation was recorded between the results obtained by these two methods which showed that the two-step method yielded cells with viability of 95 to 97% and a plating efficiency equal to that of unfrozen cells. It was concluded that such a freezing method would be ideal for the cryopreservation and storage of banks ofTheileria annulata-infected cells for vaccine purposes.

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Resumen Se congelaron a −60°C cultivos de células linfoblast bovinas infectadas conTheileria annulata. El proceso se llevó a cabo en un aparato enfriador programable, usando tasas de enfriamiento continuo de 1°C/min, 10°C/min y 120°C/min, y una tasa de enfriamiento de dos etapas, con un período de equilibración de 20 minutos a −30°C. El criopreservativo fue DMSO a concentraciones de 5, 10 y 15%. Se guardaron aliquotas del material criopreservado, et la fase vaporosa de un refrigerador de nitrógeno líquido, siendo resucitadas mediante el descongelamiento rápido en ba?o de maría a 40°C. La eficiencia de los métodos de congelamineto, se comparó evaluando la viabilidad y eficiencia de crecimiento en cultivos despues del descongelamiento, la equilibración y dilución en medios para el cultivo celular. Se obtuvo asi, una correlación significativa, entre los resultados provenientes de estos dos métodos, los cuales mostraron que el de dos etapas produjo células con una viabilidad de 95–98% y una eficiencia de crecimiento en cultivos, igual a las de las células sin congelar. Se concluyé, que este método de congelación sería ideal para la criopreservación y almacenamiento en bancos, de células linfoblastoides infectádas conTheileria annulata, para la producción de vacuua.

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Résumé Des cultures de cellules lymphoblasto?des bovines infectées parTheileria annulata ont été congelées à −60°C dans un appareil de congélation programmable, à des vitesses de 1°C/min, 10°C/min et 120°C/min et un rythme en deux temps avec une période d’équilibrage de 20 min à −30°C. Le cryopréservative était DMSO en concentrations de 5, 10 et 15%. Des échantillons aliquotes du matériel cryopréservé ont été conservés dans la phase gazeuse d’un congélateur à azote liquide et réanimés par décongélation rapide dans un bain-marié à 40°C. L’efficacité des méthodes de congélation a été jugée par l’estimation de la viabilité et de l’aptitude à coloniser des cellules après réanimation, dilution et équilibrage dans le milieu de culture cellulaire. On a obtenu une corrélation significative entre les résultats obtenus par les deux méthodes, le rythme en deux temps donnant des cellules dont la viabilité était de 95–97% et l’aptitude à coloniser égale à celle des cellules non congelées. Il a été conclu que cette méthode de congélation était idéale pour la cryopréservation et la conservation des banques de cellules infectées parT. annulata en vue de la préparation de vaccins.

     

Use of embryonating eggs for isolation of Campylobacter species from intestines of swine with proliferative enteritis

Intestinal tissues from swine affected with proliferative enteritis were ground, filtered through a 0.65-micron pore membrane filter, diluted, and injected into 7-day-old embryonated hens' eggs via the yolk sac. At 2, 4, and 7 days later, yolk sac swab specimens taken from live embryos were cultured for Campylobacter species. Campylobacter hyointestinalis was recovered from eggs injected with tissues of swine with acute hemorrhagic proliferative enteritis at dilutions up to 10(-4). Campylobacter mucosalis was recovered from eggs injected with tissues of swine with chronic proliferative enteritis at dilutions up to 10(-6). Campylobacter coli was recovered from several specimens without lesions of proliferative enteritis and also from some specimens with lesions of proliferative enteritis. Two previously undescribed hemolytic Campylobacter species designed as hemolytic number 1 and hemolytic number 2 were recovered from normal and experimentally inoculated swine tissues. Few contaminating organisms grow in eggs and these were usually recovered at dilutions of 10(-2) or less. Recovery of Campylobacter species by use of these techniques was seldom successful in tissues stored at -70 C for more than 6 months.     

The control of the level of staphylococcal contamination of the bovine udder by shed management

The role of tocopherol in animal health, and its inter-relationship with selenium and polyunsaturated fatty acids, are reviewed.     

Feline hyperthyroidism — A review

The efficacy of selenium dioxide (SeO₂) was similar to sodium selenate (Na₂SeO₄.10H₂O), in terms of increasing and maintaining blood Se concentrations. when administered orally twice daily to give 0.64 rng of Se/dav to grazing dairy cows for 56 days.     

Passive surveillance (1987 to 2004) of United Kingdom bats for European bat lyssaviruses

Passive surveillance for European bat lyssaviruses (eblvs) in the uk began in 1987, and between 1987 and 2004, 4,883 bats of European origin (4,871 belonging to 17 UK resident species and 12 belonging to seven non-uk resident species) were tested. The proportions and numbers of each species submitted from different regions varied considerably, partly owing to inherent biases in the passive surveillance, and there were seasonal variations in the numbers, sex and age of the bats. Contact with cats was reported in approximately 30 per cent of the bats submitted. Daubenton's bat (Myotis daubentonii) was the only species found to be positive for lyssavirus infection, with four cases of eblv type 2 identified, in 1996, 2002, 2003 and 2004. No active infection with eblv type 1 was recorded.