DUPLEX-ULTRASONOGRAPHIC EVALUATION OF THE COMMON CAROTID ARTERY IN THE RESTING, SEDATED AND ANESTHETIZED HORSE

The aim of this study was to determine the blood flow in the carotid artery during halothane anaesthesia by means of duplex-sonography. Seventeen warm blood horses were evaluated in dorsal and lateral recumbency and the results were compared with the values of the same horses resting and under sedation. The cross sectional area of the vessels, the time-averaged maximal blood velocity, time-averaged maximal blood flow and the resistance index were determined and the flow profile was evaluated. During halothane anesthesia the total blood flow shows a significant increase which is not dependent on the positioning of the horse. Mean blood velocity is decreased by sedation and significantly increased during anesthesia. Reduced peripheral resistance is expressed by a decline of the resistance index. After sedation and during recumbency there is an increase in diameter of the carotid artery.     

The antimicrobial activity of honey against common equine wound bacterial isolates

Delayed healing associated with distal limb wounds is a particular problem in equine clinical practice. Recent studies in human beings and other species have demonstrated the beneficial wound healing properties of honey, and medical grade honey dressings are available commercially in equine practice. Equine clinicians are reported to source other non-medical grade honeys for the same purpose. This study aimed to assess the antimicrobial activity of a number of honey types against common equine wound bacterial pathogens. Twenty-nine honey products were sourced, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys, and honeys from local beekeepers. To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. Eight products were effective against all 10 bacterial isolates at concentrations varying from <2% to 16% (v/v). Overall, the Scottish Heather Honey was the best performing product, and inhibited the growth of all 10 bacterial isolates at concentrations ranging from <2% to 6% (v/v).Although Manuka has been the most studied honey to date, other sources may have valuable antimicrobial properties. Since some honeys were found to be contaminated with aerobic bacteria or fungi, non-sterile honeys may not be suitable for wound treatment. Further assessment of gamma-irradiated honeys from the best performing honeys would be useful.     

Schwefel-Eintrag aus der Atmosphäre in Schleswig-Holstein

Atmospherical sulfur deposition in Schleswig-Holstein In order to quantify the atmospherical sulfur deposition and to investigate factors for the depositions variability during 1983 precipitation samples from five meteorological stations in Schleswig-Holstein were collected. Using the bulk-sample method dry and wet deposition were recorded together. In the year of the investigation sulfur-deposition was 20 kg/ha S in List on Sylt, 19 in Schleswig, 11 in Kiel, 14 in Lübeck and 17 in Quickborn near Hamburg. There was no correlation between sulfur concentration and pH value of the samples. In contrast sulfur-concentration showed a close relation to amount of weekly precipitations. On many soils sulfur is only added by atmospherical deposition, which is sometimes not sufficient to meet the requirements of agricultural crops in Schleswig-Holstein. Having a negative sulfur balance in soils an increase of sulfur deficiency is expected in the future.     

Viruses in the northern potato-producing regions of Saudi Arabia

Agar double diffusion tests and, later, ELISAs were used to detect viruses associated with potato in 242 samples collected in 16 trips to Tabuk and Hail, northern regions of Saudi Arabia, in four consecutive growing seasons (autumn 1989, spring and autumn 1990 and spring 1991). Eleven different viruses were detected in Tabuk and 12 in Hail. The viruses detected in Tabuk were alfalfa mosaic (AMV), cucumber mosaic (CMV), tobacco mosaic (TMV), potato leaf roll (PLRV), tomato spotted wilt (TSWV), tobacco ringspot (TRSV) and potato A, M, S, X and Y. The same viruses, plus potato yellow dwarf (PYDV), were detected in Hail. AMV was most frequently and CMV least frequently detected in Tabuk, whereas in Hail the most and least common were PVA and PLRV respectively.     

Preliminary investigation of the causal agent(s) of a disease causing leaf curl of tobacco in South Africa

A high incidence (86%) of potyvirus infection was noted in tobacco plants exhibiting a form of leaf curl in South Africa. Despite leaf curl being reported in the literature to be of geminiviral aetiology, no geminiviruses were detected. Furthermore, no other virus particles were detected by virus purification, TEM and serology. Twelve species of dsRNA were consistently isolated from these tobacco plants, but were absent from other forms of leaf curl-affected and healthy tobacco. Aphid and mechanical inoculation demonstrated that the purified potyvirus(es) did not cause leaf curl symptoms, but rather mild mottle and mosaic symptoms in tobacco. Partial characterization of the potyvirus preparation showed a possible relationship to a South African strain of potato virus Y. Because potyvirus-inoculated plants did not manifest leaf curl symptoms, and because leaf curl symptoms were noted in some plants not infected with a potyvirus, it was concluded that the potyvirus is not involved in the leaf curl aetiology, but causes a latent infection, the symptoms of which are masked. The pattern of the dsRNA banding, induction of enations and lack of mechanical and seed transmission are common to plant reoviruses. The possibility of a phytoreovirus involvement in this form of leaf curl is currently being investigated. The results from this study suggest that tobacco leaf curl disease worldwide, with regard to geminiviruses, be re-evaluated.     

Cardiovascular effects of dexmedetomidine,with or without MK-467, following intravenous administration in cats

Objective

To characterize the cardiovascular effects of dexmedetomidine, with or without MK-467, following intravenous (IV) administration in cats.

Evaluation of the infectivity of Trichinella papuae and Trichinella zimbabwensis for equatorial freshwater fishes

The discovery of Trichinella species infecting poikilotherm vertebrates has opened new possibilities in the epidemiology of this parasite group. The aim of the present work was to investigate the infectivity of the two non-encapsulated species of Trichinella infecting both mammals and reptiles, Trichinella papuae and Trichinella zimbabwensis, for equatorial freshwater carnivore fishes. To this end, two species of piranhas, four Serrasalmus nattereri and four Serrasalmus rhombeus, were each inoculated per os with the two species of Trichinella larvae. Six days post infection (p.i.), one fish of each species inoculated with one of the two species of Trichinella was sacrificed. The intestines and celomatic cavities were searched for worms using dissection microscopy, and the presence of muscle larvae was evaluated by artificial digestion. The other 4 inoculated fish were sacrificed 60 days p.i. and similarly searched for the presence of worms. No larva or adult worms were detected in any organ or tissue at 6 or 60 days p.i. The lack of infectivity of T. papuae and T. zimbabwensis for fish suggests that the entozoic habitat of this animal does not represent a suitable environment for these two Trichinella species. More importantly, these data indicate that freshwater fishes, one of the food resources for crocodiles, caimans and alligators, are unlikely to play a role in the epidemiology of the known species of the genus Trichinella.     

Spatial epidemiology of the Asian honey bee mite (Varroa destructor) in the North Island of New Zealand

We describe the spatial epidemiology of Varroa destructor infestation among honey bee apiaries in the greater Auckland area of the North Island of New Zealand. The study population was comprised of 641 apiaries located within the boundaries of the study area on 11 April 2000. Cases were those members of the study population declared Varroa-infested on the basis of testing conducted between April and June 2000. The odds of Varroa was highest in apiaries in the area surrounding transport and storage facilities in the vicinity of Auckland International Airport. A mixed-effects geostatistical model, accounting for spatial extra-binomial variation in Varroa prevalence, showed a 17% reduction in the odds of an apiary being Varroa infested for each kilometre increase in the squared distance from the likely site of incursion (95% Bayesian credible interval 7–28%). The pattern of spatially autocorrelated risk that remained after controlling for the effect of distance from the likely incursion site identified areas thought to be ‘secondary’ foci of Varroa infestation initiated by beekeeper-assisted movement of infested bees. Targeted investigations within these identified areas indicated that the maximum rate of local spread of Varroa was in the order of 12 km/year (interquartile range 10–15 km/year).     

Acceptance and digestibility of some selected browse feeds with varying tannin content as supplements in sheep nutrition in west Africa

In 1994 and 1995 leaves from 10 selected West African trees and shrubs with varying tannin content were tested to determine their suitability as an alternative and supplementary browse feed for West African dwarf sheep to improve productivity in small-scale holdings in Benin. Dry matter intake per kg metabolic body weight (DM g/kg W0.75) varied between the different browse feeds and between the different trials and ranged from zero (Leucaena leucocephala) up to 26.7 DM g/kg W0.75 (Margaritaria discoidea). The digestibility of the organic matter varied between 58.9% (L. leucocephala) and 68.2% (Mallotus oppositifolius). Agelaea obliqua showed the highest levels of total phenols (10.2%), tannin phenols (8.8%) and extractable condensed tannins (8.0%). Leaves from various browse feeds are a good and protein-rich supplementary fodder in addition to the grass Panicum maximum. However, feeding of A. obliqua and Cnestis ferruginea should be avoided due to toxic components.