Determination of prevalence and risk factors of infection with Babesia in small ruminants from Greece by polymerase chain reaction amplification

A total of 124 blood samples were collected from 92 sheep and 32 goats from 21 randomly selected herds located in two regions of Greece. Data on the characteristics of the animals (species, gender, age, tick burden, presence of haemoglobinuria, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. Nineteen animals (15%) produced the DNA fragment specific for Babesia of which 16 were sheep and three were goats. Nucleotide sequence of PCR products revealed 100% homology with Babesia ovis 18S rRNA gene. Nine farms (43%) were found positive for B. ovis. The percentage of positive animals in each farm varied between 10 and 61%. The relative risk of the presence of ticks in sheep and goats (p<0.01) and farm dogs (p<0.01) for PCR-positive results for B. ovis in sheep and goats was found 6.63 and 4.14, respectively.     

Inheritance of associated ocular and skeletal dysplasia in Labrador retrievers

A breeding colony was established to investigate the inheritance of associated ocular and skeletal dysplasia in Labrador Retrievers; 124 pups were produced. These pups were evaluated for the presence of ocular lesions, including cataracts, vitreous strands, persistent hyaloid remnants, retinal folds, retinal dysplasia, peripapillary hyperreflectivity, and rhegmatogenous retinal detachments, and skeletal abnormality, which was recognized by shorter than normal forelimbs and an abnormal morphologic appearance of the radius and ulna. Analysis of the distribution of lesions in pups indicated that the syndrome is caused by one abnormal gene, which has recessive effects on the skeleton and incompletely dominant effects on the eye. This would suggest that suspect carrier dogs could be identified by test matings with a known homozygote.     

Carbon distribution and losses: erosion and deposition effects

Because of concerns about the eventual impact of atmospheric CO₂ accumulations, there is growing interest in reducing net CO₂ emissions from soil and increasing C storage in soil. This review presents a framework to assess soil erosion and deposition processes on the distribution and loss of C in soils. The physical processes of erosion and deposition affect soil C distribution in two main ways and should be considered when evaluating the impact of agriculture on C storage. First, these processes redistribute considerable amounts of soil C, within a toposequence or a field, or to a distant site. Accurate estimates of soil redistribution in the landscape or field are needed to quantify the relative magnitude of soil lost by erosion and accumulated by deposition. Secondly, erosion and deposition drastically alter the biological process of C mineralization in soil landscapes. Whereas erosion and deposition only redistribute soil and organic C, mineralization results in a net loss of C from the soil system to the atmosphere. Little is known about the magnitude of organic C losses by mineralization and those due to erosion, but the limited data available suggest that mineralization predominates in the first years after the initial cultivation of the soil, and that erosion becomes a major factor in later years. Soils in depositional sites usually contain a larger proportion of the total organic C in labile fractions of soil C because this material can be easily transported. If the accumulation of soil in depositional areas is extensive, the net result of the burial (and subsequent reduction in decomposition) of this active soil organic matter would be increased C storage. Soil erosion is the most widespread form of soil degradation. At regional or global levels its greatest impact on C storage may be in affecting soil productivity. Erosion usually results in decreased primary productivity, which in turn adversely affects C storage in soil because of the reduced quantity of organic C returned to the soil as plant residues. Thus the use of management practices that prevent or reduce soil erosion may be the best strategy to maintain, or possibly increase, the worlds soil C storage.     

A comparison of the antinociceptive effects of xylazine, detomidine and romifidine on experimental pain in horses

Objective To study the analgesic potency of the α₂‐agonist romifidine in the horse using both an electrical current and a mechanical pressure model for nociceptive threshold testing. In addition, a comparison was made with doses of detomidine and xylazine that produce equivalent degrees of sedation. Study design Randomized, placebo‐controlled, blinded cross‐over study. Animals Six adult Swiss warmblood horses, one mare and five geldings, weighing from 530 to 650 kg and aged 6–15 years. Methods Nociceptive thresholds were measured using an electrical stimulus applied to the coronary band and using a pneumatically operated pin pressing on the cannon bone. Measurements were made immediately before and every 15 minutes for 2 hours after IV injection of the test substances. Lifting of the foot indicated the test end point. Results The three α₂‐agonists caused a temporary increase in nociceptive thresholds with a maximal effect within 15 minutes and a return to baseline levels within 1 hour. Using electrical current testing nociceptive thresholds were significantly different from placebo (mean ± SD) for detomidine at 15 minutes (from control 5.8 ± 0.9 to 23.3 ± 3.9 mA, p = 0.0066) and 30 minutes (from control 6.6 ± 1.1 to 18.8 ± 3.3 mA, p = 0.0091). The difference was significant for romifidine at 15 minutes only (from control 5.8 ± 0.9 to 18.7 ± 3.8 mA, p = 0.0066). With mechanical pressure testing nociceptive thresholds were significantly different from control for detomidine at 15 minutes (from 3.2 ± 0.2 to 6.2 ± 0.5 N, p = 0.00076) and 30 minutes (from 3.2 ± 0.7 to 5.7 ± 0.8 N, p = 0.0167). The difference was significant for xylazine at 15 minutes (from control 3.2 ± 0.2 to 5.6 ± 0.7 N, p = 0.0079). At 15 minutes the order of magnitude of the measured antinociceptive effect was significantly different between the two pain tests for both romifidine and detomidine, but not for xylazine. For romifidine, the increase of mean thresholds compared to placebo was 4.0 ± 1.3 times placebo levels with the electrical current test compared to 1.3 ± 0.3 times for the mechanical pressure test (p = 0.037). For detomidine, the increase of mean thresholds compared to placebo was 5.4 ± 1.7 times control levels with the electrical current test compared to 2.0 ± 0.2 times for the mechanical pressure test (p = 0.040). This represents a 2.7 (romifidine) and 3.4 times (detomidine) greater increase in thresholds using electrical current testing compared to the use of mechanical pressure testing. Conclusion and clinical relevance This study demonstrates the analgesic potential of α₂‐agonists in the horse for somatic pain and that they can have quantitatively different antinociceptive effects according to the antinociceptive test used.     

The scale Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in Greece

The phenology and natural enemies of Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in infesting Abies cephalonica, were studied in Greece during 1998–1999. This oviparous species develops one generation per year in Central Greece (Attica) and overwinters as 2^nd instar nymph. Young adult females appear by the end of July, and the first instar nymphs by the middle of August. By the middle of October, the whole population of the scale is recorded as 2^nd instar nymphs. The parasitoids Coccophagus lycimnia (Walker), Coccophagus Westwood sp., Aphycoides Mercet sp. and the predator Exochomus quadripustulatus L. (Coleoptera: Coccinellidae), were observed as natural enemies of the scale. The average fecundity of N. graniformis was 188.4 eggs.     

Engineering of a Single Chain Variable Fragment Antibody Specific for the Citrus tristeza virus and its Expression in Escherichia coli and Nicotiana tabacum

Citrus tristeza virus (CTV) is one of the most destructive citrus virus diseases in the world. The construction of an engineered antibody, EMBL accession number AJ278109, able to specifically recognize its antigen, i.e. the coat protein of CTV, directly on infected plant material without any purification or manipulation of the entire woody plant. The potential uses of this engineered antibody are discussed.     

Application of an enzyme-immunoassay (EIA) for rapid screening of 5 alpha-pregnane-3,20-dione (DHP) in blood plasma of the Asian elephant, Elephas maximus.

Populations of African (Loxodonta Africana) and Asian Elephants (Elephas maximus) in zoos and safari parks are at risk due to their low reproductive success. To extend the limited knowledge of their reproductive physiology, the development of easy and practical methods for the analysis of the relevant reproductive hormones is essential to support e.g. assisted reproduction. For the measurement of 5 alpha-pregnane-3,20-dione (DHP), the predominant ovarian gestagen in both species, an enzyme-immunoassay (EIA) based on commercial reagents was applied. Advantages of this EIA are the small volume of plasma needed for evaluation (5 microliters) and the possibility of direct processing without an extraction stage. The lower limit of detection was 0.16 ng/ml, the mean recovery was 101% and the mean coefficients of variation were 7.3% (intra-assay) and 9.9% (inter-assay). In Asian elephants, DHP levels reached 15 ng/ml during the luteal phase and up to 21 ng/ml during pregnancy. Estrous cycle lengths based on the lowest DHP concentrations varied from 12 to 20 weeks (mean 15.4 +/- 2.3). In two Asian elephant cows a calf was still-borne. Thereafter, the animals reassumed ovarian activity after approximately 8 and 13 weeks, respectively. In one animal estradiol implants for hormonal contraception caused a down regulation of the ovarian function as demonstrated by an irregular pattern of DHP secretion over a period of 48 weeks. We propose the direct DHP-EIA as a suitable method for reproductive monitoring in elephants, as it can be easily established in laboratories.     

Isolation of viral haemorrhagic septicaemia virus from mummichog, stickleback, striped bass and brown trout in eastern Canada

Viral haemorrhagic septicaemia virus (VHSV) was isolated from mortalities occurring in populations of mummichog, Fundulus heteroclitus, stickleback, Gasterosteus aculeatus aculeatus, brown trout, Salmo trutta, and striped bass, Morone saxatilis, in New Brunswick and Nova Scotia, Canada. The isolated viral strains produced a cytopathic effect on the epithelioma papillosum cyprini cell line. Serum neutralization indicated the virus was VHSV and sequencing identified the rhabdovirus isolates as the North American strain of VHSV. Phylogenetic analysis indicated that the isolates are closely related and form a distinguishable subgroup of North American type VHSV. To our knowledge, this is the first report of VHSV in mummichog and striped bass.     

Titres of precocene ii (6, 7-dimethoxy-2, 2- dimethylchromene) and its metabolites in the haemolymph of larvae of the african armyworm Spodoptera exempta (walker) following topical treatment with the compound

No precocious metamorphosis or other morphogenetic effects were seen following topical treatment of fifth instar Spodoptera exempta with pre- cocene II. [3H]-Precocene II penetrated the larvae rapidly following topical application. An uptake of 47% was recorded in the first hour and an average of 27% for the first 3 h. Radioactivity in the haemolymph reached a maximum 4 h after treatment at 6–8% of the applied dose. A maximum titre of precocene of 1.1 × 10^?4 _M was observed 2 h after treatment and a biological half-life of around 1 h was recorded for the first 6 h. The metabolite precocene 11–3, 4-dihydrodiol appeared in the haemolymph with a maximum titre of 1.1 × 10^?4 _M at 4 h suggesting metabolism via the 3, 4-epoxide. At the same time an unidentified metabolite was observed possibly corresponding to the 6- and 7-(O)-desmethylated products described by others. Very large quantities of highly polar materials were observed in the haemolymph throughout the experiment and it is thought that these corresponded to conjugates. The evidence suggests that peripheral detoxication mechanisms do not operate sufficiently rapidly to prevent the establishment of a high titre of precocene. This, however, did not affect the corpora allata in this insect, whereas in a sensitive species that has been studied by other workers, necrosis of the glands would have resulted. Alternative explanations for insensitivity are discussed.     

Epidemiology and simulation of population development of Sitobion avenae in winter wheat

The epidemiology ofSitobion avenae and its natural enemies in winter wheat was studied in 1975, 1976 and 1977. Immigration was important until the end of flowering. The alate immigrants had apterous offspring. These became the driving force in population growth. Their offspring were mostly alatae which usually left the field. A model of the epidemic was developed. Quantitative relations between the aphids and their environment were obtained from literature or established in laboratory trials. The model simulated population development and population composition from the beginning of June till the population peak at the end of June or early in July. Because quantitative data on relations between aphids and their natural enemies and pathogens are scarce, and since the knowledge on wing formation is still limited, the population collapse could not be predicted. In the future, prognosis over a period of three weeks seems possible.Samenvatting De toenemende betekenis van graanbladluizen (vooralSitobion avenae) gepaard gaande met een sterke toename van het gebruik van insecticiden op granen maakte verbetering van de prognose over het schadelijk optreden wenselijk. Door gedetailleerde tellingen in het veld (Fig. 1–7) werden gegevens verkregen over het verloop van de epidemie en het optreden van natuurlijke vijanden in 1975, 1976 en 1977.Een immigratieperiode tot in de bloei kon worden vastgesteld. Daarna lijkt de aantrekkelijkheid van het gewas voor alate luizen te verminderen. De alate immigranten krijgen aptere nakomelingen. Deze vormen de stuwende kracht van de populatiegroei. De nakomelingen van apteren zijn merendeels alaat. Zij verlaten het gewas.Een model van de populatieontwikkeling gedurende de epidemie werd opgesteld. De relatiediagrammen Fig. 9 en 10 laten groei en ontwikkeling vanS. avenae en een predator (Syrphus corollae) zien. Kwantificering van de betrekkingen werd mogelijk door literatuurgegevens en laboratoriumexperimenten.Met het model kon de populatieontwikkeling vanS. avenae vanaf begin juni tot aan de populatiepiek in 1975, 1976 en 1977 vrij goed worden gesimuleerd (Fig. 12). Ook de populatieopbouw kon worden gesimuleerd (Fig. 14). De teruggang van de populatiedichtheid blijkt moeilijker te voorspellen door het ontbreken van gegevens over natuurlijke vijanden.Het lijkt waarschijnlijk dat in de toekomst met het model een prognose over de piek van de bladluispopulatie circa 3 weken tevoren mogelijk zal zijn.