Uptake of drugs from topically applied anti-inflammatory preparations applied to racing animals

Objective To determine whether a drug detected in the blood or urine of a racing animal could have penetrated through the skin from a topically applied preparation.
Design Blood and urine of dogs and horses were analysed after topical administration of three common nonsteroidal anti-inflammatory preparations.
Experimental method Dimethylsulphoxide was analysed using a gas chromatograph with a flame photometric detector. Phenylbutazone, its metabolites and lignocaine were analysed using a gas chromatograph with a mass selective detector.
Results Dimethylsulphoxide, phenylbutazone and ligno-caine were detected in dog urine after muliple applications of the preparations. The maximum concentration of dimethyl-sulphoxide in dog urine correlated with the concentration of dimethylsulphoxide in the preparation. Phenylbutazone penetrated the skin more effectively from the cream than from the solution or gel preparations. This penetration was independent of the concentration of dimethylsulphoxide.
Conclusion The superior penetration of phenylbutazone from the cream can be explained by it being present as a neutral molecule in an hydrophobic medium. It is proposed that phenylbutazone penetrates the skin of greyhounds most effectively by a hydrophobic lipid route which is likely to be different from the path by which dimethylsulphoxide penetrates the skin.     

Cardiomyopathy of ruminants induced by the litter of poultry fed on rations containing the ionophore antibiotic, maduramicin. I. Epidemiology, clinical signs and clinical pathology.

The epidemiological, clinical and clinical pathological findings in 20 cattle and 4 sheep from 15 outbreaks of poultry litter toxicity in South Africa over the past 6 years are documented. In 6 outbreaks, the litter emanated from batteries where maduramicin had been incorporated into rations of broilers. According to circumstantial evidence the litter involved in the 9 other outbreaks was also derived from broilers which had been fed on rations containing an ionophore. The litter was fed ad libitum to the affected stock or constituted 30-80% by volume of their rations. The principal sign manifested was sudden mortality of up to 70% of the herd or flock, usually within 20-40 days of commencement of feeding of poultry litter. A few cattle developed signs of congestive heart failure, and stiffness was commonly seen in sheep. In a dosing trial with poultry litter involving 1 steer and 6 sheep, the steer and a sheep died suddenly and a second sheep was destroyed in extremis. Tachycardia and/or cardiac arrythmia were recorded in 5 sheep, and the activity of aspartate transaminase (AST) and/or lactate dehydrogenase (LD) in the sera of 4 was elevated. Since the cardiac lesions in field cases were similar to those of ionophore poisoning and broiler rations containing maduramicin was a common factor in several outbreaks, toxic litter from some of these outbreaks were tested for the presence of this compound. Analysis by high performance liquid chromatography of litter from 2 specimens of outbreaks revealed that they contained 2.5 ppm and 6.1 ppm maduramicin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Some wild hosts of the Karoo paralysis tick, Ixodes rubicundus Neumann, 1904 (Acari: Ixodidae)

A variety of mammal and bird species in the Mountain Zebra National Park, eastern Cape Province, were examined for Ixodes rubicundus. In addition, caracal (Felis caracal) from the park and its vicinity as well as from the Graaff-Reinet region of the Karoo were examined. Amongst the animals collected, the red rock rabbit (Pronolagus rupestris) was a preferred host of the immature stages of the tick. Caracal were moderately good hosts of these stages and, with mountain reedbuck (Redunca fulvorufula) and eland (Taurotragus oryx), are the preferred hosts of adult ticks.     

Prevalence and clonal diversity of Campylobacter jejuni from dairy farms and urban sources

AIM: To investigate the role of free-living animals such as spar- rows, rodents and flies as potential reservoirs of Campylobacter spp on a dairy farm, and to assess the genetic diversity among Campylobacter isolates from the farm and an urban source.

METHODS: A total of 290 samples (bovine, passerine and ro- dent faeces, and whole flies) were collected from a large com- mercial dairy farm in the Manawatu district in New Zealand, and from faeces from urban sparrows in a nearby city. Other samples collected from the dairy farm included five from silage, two from aprons worn by workers during milking, two from workers' boots and two from water in troughs in a paddock. Isolates of thermophilic Campylobacter spp were identified mor- phologically and phenotypically and further characterised mo- lecularly using pulsed-field gel electrophoresis (PFGE) and the restriction enzyme SmaI.

RESULTS: Campylobacter jejuni was the only Campylobacter species isolated from all samples. The highest prevalence was found in faeces from dairy cows (54%), followed by faeces from sparrows from the urban area (40%) and the farm (38%), and from rodents (11%) and whole flies (9%). Other samples from the farm environment such as silage, trough water, and work- ers' aprons and boots were also positive for C. jejuni. Of the 22 restriction patterns obtained, seven were common to more than one source.

CONCLUSIONS: Cattle, sparrows, rodents and flies are po- tential reservoirs of C. jejuni on dairy farms. Identical clones of C. jejuni carried by cattle, sparrows, flies and rodents prob- ably indicate a common source of infection. The high level of asymptomatic carriage of C. jejuni by healthy dairy cows could be sufficient to maintain infections within the dairy farm sur- roundings via environmental contamination.     

Evaluation of the grazing potential of grass species in Tarchonanthus veld of the northern cape 1

Abstract

The grazing value of the seven most prominent grass species in Tarchonanthus‐limeveld was investigated from 1977 to 1981.

The frequency of utilization of Chrysopogon serrulatus was exceptionally high (93%), while Sporobolus fimbriatus, Themeda triandra and Digitaria seriata were intermediate (50–60%) followed by Cymbopogon plurinodis (34%). Eragrotis lehmanniana and Fingerhuthia africana were poorly grazed (12 to 16%). The utilization of species was influenced by stocking rate. Statistical differences between species indicated a relatively high biomass production (600 to 740 g DM/m² per year) for E. lehmanniana, C. plurinodis and T. triandra, while F. africana, S. fimbriatus and D. seriata were intermediate (320 to 420 g DM/m² per year). E. lehmanniana, C. plurinodis and T. triandra produced the highest above‐ground phytomass, but had a lower crude protein content (2,9 to 7,4%) and digestibility (46,1 to 61,3%) than the other four species (3,8 to 9,7% crude protein and 50,5 to 68,4% digestibility).     

Veldtoestand en neiging in Kalahari‐duineveld onder ‘n ekstensiewe veeboerderystelsel

Uittreksel

Plantopnames is gedurende 1970 tot 1985 in die Kalahari‐duineveld (Acocks, 1975; Veldtipe no. 16a4) op die proefboerdery‐eenheid Massakloutjie in Noordwes‐Kaapland onderneem. Reënval het gedurende die proefperiode gewissel tussen 111 mm (1982–83) en 593 mm (1973–74). Die totale basale plantebedekking het gevarieer van 2,39 % (1983) tot 6,17 % (1977). Die voorkoms van periodes met hoë en lae reënval word weerspieël in die botaniese samestelling van die duineveld.

Groep A spesies (afnemers/hooggewenstes) vorm die dominante komponent (tot 90 %) gedurende ‘n droë siklus, weens ‘n groter droogtebestandheid. In ‘n nat siklus vermeerder die Groep B, C en D spesies (toenemers/minder gewenstes en onge‐wenstes) vinniger as die Groep A spesies en maak tot soveel as 50 % van die botaniese samestelling uit. Weens die sikliese aard van die botaniese samestelling (relatiewe bedekking) vorm absolute bedekking van spesiegroepe ‘n meer betroubare maatstaf van relatiewe veldtoestand as botaniese samestelling. Geskikte plantopnametegnieke vir die Kalahari‐duineveld word be‐spreek. Daar is aangetoon dat onder ‘n realistiese veelading ‘n ekonomies vatbare veeboerdery in die duineveld bedryf kan word, sonder dat die hulpbron beskadig word.     

The Relative host status of rock elephant shrews Elephantulus myurus and Namaqua rock mice Aethomys namaquensis for economically important ticks

Several tick species of medical and veterinary importance occur in the southern Orange Free State. The purpose of the present study was to determine the host status of rock elephant shrews ( Elephantulus myurus) and Namaqua rock mice ( Aethomys namaquensis) for these ticks. Infestation levels were used as a criterion. The seasonal abundances of the ticks as well as the effects of landscape topography and sex of the host on infestation levels were also investigated. Incidental observations were made on the pouched mouse (Saccostomys campestris). No adult ticks were recovered from any of these small mammals. Seven tick species were found on the elephant shrews of which only Ixodes rubicundus and Rhipicephalus punctatus occurred in high numbers on a large proportion of the animals. Both these ticks cause paralysis in domestic stock. The Namaqua rock mice harboured eight tick species. Only Haemaphysalis leachi/spinulosa and R. punctatus had a relative abundance exceeding 15%. Three of the 10 pouched mice examined were infested with small numbers of ticks. The 132 rock elephant shrews examined harboured a mean total burden of 121 immature ticks compared to four on each of the 321 Namaqua rock mice. The larvae and nymphs of I. rubicundus occurred mainly in the colder months (April to September), while those of H. leachi/spinulosa preferred the warmer months (October to March). Large numbers of larvae of R. punctatus were present from December to July and nymphs from August to October. Infestation levels of I. rubicundus were consistently higher on animals trapped on southern slopes than on those trapped on northern slopes. The sex of the hosts seemed to have little effect on infestation levels.     

Scientific critique of the paper “Climatic distribution of citrus black spot caused by <Emphasis Type="Italic">Phyllosticta citricarpa</Emphasis>. A historical analysis of disease spread in South Africa” by Martínez-Minaya et al. (2015)

The global distribution of citrus black spot (CBS) disease, caused by Phyllosticta citricarpa, is climatically constrained, which is evident from its occurrence in citrus growing areas with warm, summer rainfall and its absence from areas with cooler, Mediterranean-type winter rainfall. Various epidemiological and modelling studies have supported this observation, predominantly estimating unsuitability for P. citricarpa in Mediterranean type climates, with no more than marginal suitability estimated at a few localities within some regions with Mediterranean type climates. The study by Martínez-Minaya et al. (European Journal of Plant Pathology, 143, 69–83, 2015), describes an historic sequence of recorded CBS occurrence in parts of South Africa, conducts an autocorrelation analysis and a correlative analysis with Köppen-Geiger climate zones and makes observations about the occurrence of certain Köppen-Geiger climate zones in the European Union. The study suggests that significant portions of the European Union and the broader Mediterranean basin are climatically similar to warm, summer rainfall areas in South Africa where P. citricarpa persists and causes CBS disease and concludes that the potential distribution of P. citricarpa is less constrained by climatic factors than spatial contagion. However, in this critique we expose methodological shortcomings in the Martínez-Minaya et al. (European Journal of Plant Pathology, 143, 69–83, 2015) study and conclude that the study grossly overestimated the extent of the geographical area that could support P. citricarpa, thereby rendering the findings scientifically unreliable.     

The use of adjuvants to improve spray deposition and Botrytis cinerea control on Chardonnay grapevine leaves

Spray adjuvants have the potential to improve deposition by effecting uniform distribution of the active ingredient on plant surfaces. In order to study whether such a qualitative improvement of spray deposition would lead to improved disease control, a laboratory experiment was conducted on artificially inoculated grapevine (cv. Chardonnay) leaves. Prior to inoculation with Botrytis cinerea conidia in a spore settling tower, leaves were sprayed to pre-runoff with 1 mL of a mixture of fenhexamid, a fluorescent pigment, and one of 15 selected commercial adjuvants to manipulate the deposition quality of a specific quantity of spray. Following an incubation period of 24 h at high relative humidity, leaf discs were plated onto Petri dishes with paraquat-amended water agar and rated for development of B. cinerea from isolated leaf discs 11 d later. Spray deposition on leaves was assessed with a spray assessment protocol using fluorometry, photomicrography and digital image analyses. B. cinerea incidences on the upper and lower surfaces of water-sprayed leaves averaged 90.4% and 95.8%, respectively. Despite full spray cover of leaves, applications with fenhexamid alone did not completely prevent infection and resulted in 34.6% and 40.8% B. cinerea incidences on the upper and lower surfaces of leaves, respectively. Through the addition of certain adjuvants, B. cinerea incidences were significantly reduced (incidences of 2.9–17.1% and 10.0–30.8%, respectively), while some adjuvants did not differ from the fungicide only treatment, even though they might have improved spray deposition. In a histopathology study using epifluorescence microscopy, distinct differences were observed in conidium mortality (20.5% vs. 31.2%), germination (60.4% vs. 51.4%) and germ tube lengths (27.8 μm vs. 19.7 μm) between Hydrosilicote and Solitaire in combination with fenhexamid, even though both adjuvants effected similar quantitative and qualitative spray deposition. The study clearly demonstrated the potential of adjuvants to improve the bio-efficacy of a fungicide directly through improved deposition on grapevine leaf surfaces, although bio-efficacy might be influenced by adjuvant mode of action in some cases.     

Photometric application of the MTT- and NRR-assays as biomarkers for the evaluation of cytotoxicity ex vivo in Eisenia andrei

In soils, the toxicity of noxious substances such as metals is determined by a number of different factors of chemical, physical, biological, and environmental origin. Addressing these factors as a sum of different parameters, we studied these effects in soil-dwelling indicator species by using ‘sub-cellular’ biomarkers, to see if they can provide an early stage response to environmental disturbances. ‘Sub-cellular’ biomarkers such as the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and the Neutral Red Retention (NRR) assays are well established for the assessment of cytotoxicity of toxicants on cell cultures. Both assays can be carried out in 96-well microplates and evaluated photometrically. To be able to assess the risk potential of contaminated soils using these assays, without changing the soils chemically or physically to accommodate cell cultures, the assays were adapted for ex vivo use. The assays were performed on coelomic liquid extracted from exposed earthworms. Eisenia andrei was exposed in a standardized laboratory soil substrate (OECD soil) spiked with cadmium at a range of concentrations known to be cytotoxic to earthworms. Earthworms were also exposed to ultramafic soils as field-relevant soil substrates, containing high concentrations of a mixture of metals of natural origin such as chromium, cobalt, manganese, and nickel. A significant response was measured with both assays in the coelomocytes of the earthworms exposed to the Cd-spiked OECD soil as well as to the ultramafic soils. It was shown that as biomarkers for the assessment of ‘sub-cellular’ toxicity, the photometrical application of the MTT and the NRR assay promised to be rapid, objective, and easily conductible tools.