Experimental quantification of the transmission of Sarcoptes scabiei var. suis among finishing pigs

In this study, the rate of S. scabiei var. suis transmission among finishing pigs was quantified in a contact transmission experiment. Forty piglets originating from a mange free farrow-to-finish herd were randomly allocated to three groups and one S. scabiei var. suis infested finishing pig was subsequently added to each of these groups. After 35 days, the three seeder pigs were removed from the groups and the remaining 40 pigs were re-allocated to five pens. Ear scrapings, to be examined for mites, were collected from each pig on days 1, 14, 28, 42, 56, and 84 of the experiment. Blood samples, to be tested for antibodies against S. scabiei, were collected from each pig on days 0, 14, 28, 42, 56, 70, 84 and 112 after the introduction of the seeder pigs.From the results of the ear scrapings and the blood samples the number of susceptible (not infested) and infested pigs was derived at the time of each sample collection and the number of new infestations in the intervals between the sample collections. From these data the infestation rate parameter beta (average number of new infestations per infested pig per day) was estimated by use of a Generalised Linear Model (GLM) and accordingly, beta was estimated at 0.056 (95% CI: 0.037-0.085) infestations per infested pig per day.Next, by use of beta, the transmission of S. scabiei was simulated in a population of 100 finishing pigs for 100 days after the introduction of a single infested pig. For this purpose, 500 simulations were done. The 90% confidence interval of the number of infested pigs at day 100 ranged from 12 to 88 (median: 63). It was concluded that transmission of S. scabiei among finishing pigs is slow. Due to the presumed lower contact rate between sows as compared to finishing pigs, it is anticipated that transmission of S. scabiei among sows will even be slower than among finishers These findings are of particular interest for the development of surveillance programmes for S. scabiei free herds.     

Validation of ELISAs for the detection of antibodies to Sarcoptes scabiei in pigs

An Enzyme-linked ImmunoSorbent Assay (ELISA) was developed for the detection of antibodies to Sarcoptes scabiei. This 'Animal Health Service'-ELISA (AHS-ELISA) was compared with a commercial test (Checkit(R) Sarcoptest) using experimental and field sera. The experimental study was a contact infestation experiment. Eighty piglets were randomly divided between the experimental and control group. After introduction of three Sarcoptes scabiei var. suis infested pigs in the experimental group, both groups were monitored by determining scratching indices, taking ear scrapings and blood samples in Weeks 0, 2, 4, 6, 8, 12 and 16. Four pigs in the control group were immunised with either Dermatophagoides pteronyssinus (Dp) antigens (n=2), or Acarus siro (As) antigens (n=2). In the control group all (non-immunised) pigs were negative in all tests. In the experimental group only slightly elevated scratching indices were observed, with a maximum in Week 8. After 2 weeks for the first time an ear scraping was positive (2.5%). In Week 8 the highest number of positive ear scrapings were found (25.0%). Positive results in the Sarcoptest were first obtained in Week 12 (10.5% positive), while eventually 29.0% of the finishing pigs were positive after 16 weeks. The AHS-ELISA first detected a serological response after 6 weeks (5. 0% positives), increasing until after 16 weeks a large proportion (74.2%) of the finishing pigs were seropositive, making the AHS-ELISA the most sensitive test. In the AHS-ELISA one As-immunised pig remained seronegative, but the other hyper-immunised pigs crossreacted. In the Sarcoptest, only Dp-immunised pigs had elevated Optical Densities (OD's) albeit below the cut-off level. Although hyper-immunisation is not a representation of field conditions, it cannot be excluded that the AHS-ELISA is not 100% specific.Field samples were taken from 20 sows in 30 herds, classified as mange-free, suspect, or infested. On a herd level there was high agreement among the ELISAs. Both serological tests were suitable to distinguish mange-free herds from infested herds. In one infested herd the decline of maternal antibody in piglets was studied by sampling 40 piglets from 20 different litters. The lowest average OD using the AHS-ELISA was found at 5 weeks of age, followed by a significant increase at 7 weeks. The average OD with the Sarcoptest was at a minimum level at 3 weeks, but no increase was found later. For screening of herds, interference of maternal antibodies is avoided by sampling at an age of 7 weeks or older.     

Identification of a blue photoluminescent composite material from a combinatorial library

A quaternary combinatorial masking strategy was used in conjunction with photolithography to generate compositionally diverse thin-film phosphor libraries containing 1024 different compositions on substrates 2.5 centimeters square. A parallel imaging system and scanning spectrophotometer were used to identify and characterize compositions in the library with interesting luminescent behavior. Optimal compositions were identified with the use of gradient libraries, in which the stoichiometry of a material was varied continuously. This process led to the identification of an efficient blue photoluminescent composite material, Gd3Ga5O12/SiO2. Experimental evidence suggests that luminescence in this material may arise from interfacial effects between SiO2 and Gd3Ga5O12.     

Lunar Fe and Ti abundances: comparison of lunar prospector and clementine data

The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region.     

Report on the 43rd Annual Meeting of the DPG-Working Group Nematology

Journal of Plant Diseases and Protection -     

Comparison of Two Doses of the GnRH Antagonist, Acyline, for Pregnancy Termination in Bitches

Gonadotropin-releasing hormone (GnRH) antagonists are particularly useful when a rapid inhibitory effect on the gonadal axis is required. The aim of this study was to test the efficacy and clinical safety of a low and high dose of the third generation GnRH antagonist, acyline, on pregnancy termination in female dogs. The effect of the antagonist on the progesterone (P₄) serum concentration was also described. Twenty-one mid-pregnant bitches were randomly assigned to a single subcutaneous (SC) dose of a placebo (PLACE; n = 7), a low (ACY-L; 110 μg/kg; n = 6) or high (ACY-H; 330 μg/kg; n = 8) dose of acyline. The animals were followed up for 15 days. All ACY treated but no placebo-treated animals terminated their pregnancy by abortion (p < 0.01). The ACY-L and ACY-H groups interrupted their pregnancy 7 ± 1.9 and 6.4 ± 1.3   days after treatment, respectively (p = 0.7). A significant interaction between treatment and day was found (p < 0.01) for P₄ serum concentrations when PLACE was compared with both ACY groups. No difference was found for this hormone between both ACY groups (p > 0.05) where P₄ diminished throughout the study. The decreasing rate varied among animals and was closely related to the time of abortion when P₄ reached basal concentrations. In PLACE animals, gestation progressed normally and P₄ did not change throughout the study (p > 0.05). None of the bitches presented side effects. It was concluded that acyline safely terminated mid-pregnancy by permanently decreasing P₄ serum concentrations.     

Reproductive Performance of Rabbit Does Artificially Inseminated via Intravaginal Administration of [des-Gly 10, d-Ala6]-LHRH Ethylamide as Ovulation Inductor

This study was aimed to evaluate the reproductive performance of rabbit does artificially inseminated (AI) with a GnRH analogue [des‐Gly10, d ‐Ala6]‐LHRH. ethylamide to induce ovulation by intravaginal administration, delivered in the seminal dose. In a preliminary experiment, 39 does were divided into three groups (n = 13) that, at the time of AI, received the following ovulation induction treatments: (i) control group: 20 μg of gonadorelin administered intramuscularly; (ii) 25 μg of the GnRH analogue added to the seminal dose; (iii) 30 μg of the GnRH analogue added to the seminal dose. Fertility did not differ between the three groups (control: 80.6%, group 2: 82.8%, group 3: 73.3%). In a second experiment, a large‐scale field trial was conducted to test the use of 25 μg of the GnRH analogue [des‐Gly10, d ‐Ala6]‐LHRH ethylamide delivered in the seminal dose (n = 270) against 20 μg of gonadorelin administered intramuscularly. Fertility was higher (p < 0.05) when ovulation was induced by intravaginal administration of the GnRH agonist (91.1% vs 85.6%). Prolificacy or mortality at birth was never affected by the ovulation induction treatments. In a third experiment, two groups of does [control group (n = 39): ovulation was induced using 20 μg of gonadorelin administered intramuscularly; treatment group (n = 40): ovulation was induced using 25 μg of [(des‐Gly10, d ‐Ala6)‐LHRH ethylamide added to the seminal dose] were inseminated at 42‐day intervals for five successive AI cycles, to test the response to the GnRH agonist after repeated intravaginal administration to the same animals. Fertility and prolificacy were not influenced by the ovulation induction treatment neither there was an interaction between treatment and parity. The last experiment was aimed to determine whether it could be possible to add the GnRH agonist to the semen in the AI Center, just after semen collection and dilution, or it would have to be added in the farm, immediately before AI. Kindling rates did not significantly differ when ovulation was induced by intramuscular injection of gonadorelin (84.5%) or when the GnRH agonist was added to the seminal dose just at the moment (93.8 %) or 24 h before AI (90.4 %), but it was significantly lower when the hormone was added to the semen 32 h before AI (76.3 %). Prolificacy, however, was not influenced by the ovulation induction treatment.     

Use of Cholesterol‐Loaded Cyclodextrin in Donkey Semen Cryopreservation Improves Sperm Viability but Results in Low Fertility in Mares

The use of cholesterol‐loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S‐MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10⁶ spermatozoa. Semen was frozen, and thawed samples were evaluated by computer‐assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen‐thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC‐treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC‐treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC‐treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S‐MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S‐MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.